JPH11217500A - Polymer blend - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymer blend excellent in the balance among chemical resistance, toughness, and low-temp. flexibility by melt blending a vinyl or vinylidene halide polymer with a polyamide in the presence of a specific ethylene polymer as a compatibilizer. SOLUTION: The compatibilizer for a halide polymer and a polyamide is an ethylene polymer having carbon monoxide and/or carboxyl functionality. In the polymer blend, the wt. ratio of the polyamide to the halide polymer is about 1.5 to about 2; and the ethylene polymer is present in an effective amt., not higher than about 80 wt.% of the halide polymer. The ethylene polymer pref. has both carboxyl groups and carbon monoxide, an example being an ethylene-alkyl methacrylate-carbon monoxide copolymer. Polyvinyl chloride is pref. as the halide polymer. Nylon MPMD 6 and nylon MPMD 12 are pref. as the polyamide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This application claims the benefit of pending US patent application Ser. No. 08 / 955,724, filed Oct. 22, 1997, which was disclaimed. Claims of U.S. Patent Application Serial No. 08 / 701,519 (filed August 22, 1996)
U.S. Patent Application No. 60 / 022,851
No. (filed August 28, 1995).

The present invention relates to blends of vinyl halide or vinylidene halide polymers, polyamides, and compatibilizing polymers, the components of which are suitable for wire and cable jacketing and chemical resistant liners. It is blended in a ratio such that a tough, flexible, chemically resistant composition is obtained.

[0003]

2. Description of the Related Art U.S. Pat. No. 5,352,735 (Hofmann)
(Incorporated herein by reference)
The discovery that vinyl halide or vinylidene halide polymers and polyamides can be melt blended under certain conditions that result in relatively low melting halide polymers that do not undergo degradation and that provide useful blend products. The method of U.S. Pat. No. 5,352,735 discloses that the halide polymer and the polyamide are combined in the presence of an effective amount of an ethylene polymer having carbon monoxide and / or carboxyl functionality to compatibilize the halide polymer and the polyamide. Are melt blended together at a temperature of less than about 220 ° C., provided that the polyamide is melt processable at the temperature of melt blending.

[0004]

SUMMARY OF THE INVENTION U.S. Pat. No. 5,352,735
The article also teaches compositions containing these polymer components, but does not teach or suggest the chemical resistance of the resulting compositions. The patent teaches that the ratio of the halide polymer to the polyamide can vary widely (5 to 95% by weight for each 100% by weight of the two polymers). In all examples, the polyamide is present in the blend in a weight of PVC polymer.
It is present in 1.3 times the amount.

[0005]

SUMMARY OF THE INVENTION The present invention provides an improved composition comprising a vinyl halide or vinylidene halide polymer, a polyamide, and a compatibilizing ethylene polymer having carbon monoxide and / or carboxyl functionality. Including discovery. These compositions exhibit an excellent balance of properties including chemical resistance, toughness and low temperature flexibility.

[0006] In particular, the composition of the present invention comprises a fuel C at room temperature.
(Fuel C) (including a 50/50 mixture of isooctane and toluene) after 7 days of immersion, including those with a residual tensile strength greater than about 60% and a volume swelling of less than about 20%. The polyamide of the present invention is present in the composition in an amount of 11/2 to 2 times the amount of halide polymer in the blend, and the ethylene polymer having carbon monoxide and / or carboxyl functionality has a halide polymer content. Is present in an amount up to 80% by weight with respect to

[0007]

DETAILED DESCRIPTION OF THE INVENTION Plasticized polyvinyl chloride (PVC)
Is the only largest volume electrically insulating material currently in use. This not only has good electrical properties,
Has very good abrasion and moisture resistance. Soft (f
lexible) PVC insulation is used for construction wires, power cables,
It is applied to wiring of electric appliances, wiring of automobiles, and wiring for communication.

[0008] Underwriters Laboratory (Unde
rwriters Laboratory), THHN structure (THHN const
A particularly high performance insulation, defined as ruction, is typically a 15 mil (0.38 mm) flexible PVC insulation layer covered with a 4 mil (0.10 mm) polyamide jacket (sheath or jacket). Become. This insulating layer must meet the minimum electrical standards, and the main role of the polyamide jacket is chemical resistance, wear resistance and toughness.

For the production of such a two-component structure,
It is necessary to use two melt extrusion operations. In the first melt extrusion operation, the bare wire is coated with a soft PVC insulation layer. After this, the second extrusion operation is performed,
Here, a polyamide is coated on the soft PVC layer previously deposited.

[0010] For waste or reclaimed structures, it is necessary to peel off the polyamide layer from the flexible PVC insulation for recycling and to peel off the PVC layer from the wire for recycling. Cross-contamination of incompatible polyamide in recycled PVC material and PVC in recycled polyamide material is a serious problem and is considered to be useless, and landfill waste (lan
It often results in material being dumped as dfill waste).

The present invention eliminates the need for a two-layer structure by using the composition of the present invention, so that the two extrusion operations can be reduced to a single extrusion operation, thus reducing the extrusion process. Can be greatly simplified.

A second advantage is that the need for separating the polyamide jacket from the flexible PVC insulation layer during the recycling operation has been eliminated.

A third advantage is that it eliminates intercontamination between the polyamide jacket material and the soft PVC material during recycling, thereby reducing the amount of material dumped as landfill waste. is there.

A wide variety of compositions comprising a vinyl halide, a polyamide having a melting point of less than about 220 ° C., and an ethylene polymer having carbon monoxide and / or carboxyl functionality, provided that the ethylene polymer comprises the halide polymer and the ethylene polymer. Added to compatibilize with polyamide)
Has been found to impart most of the required physical properties to wire (cable) and cable insulation. Over a wide range of compositions, they provide toughness as measured by a notched Izod and flexibility as measured by the point of brittleness.

However, it has now surprisingly been found that good chemical resistance as measured by exposure to fuel C (50/50 mixture of isooctane and toluene) (immersion at room temperature for 7 days) indicates that the halide polymer It has been found that this is only achieved if the ratio of ethylene polymer to polyamide is maintained at a relatively limited ratio. In particular, the composition must be relatively rich in polyamide.

[0016] A variety of structures can be made, including coatings of the compositions of the present invention. For example, the composition may be coated on a wire substrate, which may be manufactured as a sheeted membrane, and a pipe liner.
Or may be used as a thermoformed container
ainers).

The polyamide present in the composition of the present invention may comprise about 1.% (by weight) of the halide polymer present.
It should be present in 5 to about 2 times, preferably about 1.75 to 2 times. These compositions must also contain an ethylene polymer to compatibilize the polyamide / halide polymer blend.

The amount of ethylene polymer incorporated in the melt blend depends on the halide polymer and the polyamide.
(one with the other) should be in an amount effective to make it compatible. Typically, this amount will be in the range of up to about 80% by weight, based on the weight of the halide polymer. When a high melting polyamide such as nylon 6 is included in the blend, to obtain an effectively compatibilized blend,
Preferably, large amounts (ie 20-80%, preferably 40-60% by weight, based on the weight of the halide polymer) of ethylene polymer should be used. MPMD, 6 and MPMD, 12
If a low melting polyamide such as nylon is included in the blend, a small amount (i.e., 1-40%, preferably 1-20% by weight, based on the weight of the halide polymer) of ethylene polymer should be effective. is there. Also, a preferred composition can be obtained when some of the polyamide and halide polymers together with the ethylene polymer are present at a level of from about 20 to about 50% by weight based on the weight of the halide polymer.

A particularly preferred composition comprises a blend of a polyamide, a halide polymer, and an ethylene copolymer (and stabilizers and other additives used in the art), wherein the polyamide (based on the total weight of the polymer). Compositions that make up more than about 45%). These compositions achieve a volume swell value of less than about 20% with a residual tensile strength of greater than about 60%. Compositions consisting of these three polymers, containing less than about 45% polyamide (based on total polymer weight), absorb fuel C in very large amounts (typically more than 30%) and only about 55%
% Or less of the tensile strength. A preferred composition consisting of these three polymers (and their stabilizers and additives) comprises about 65% by weight (based on polymer weight)
The following polyamide components are contained.

The vinyl halide or vinylidene halide polymer preferably contains chlorine as the halogen moiety. Polyvinyl chloride (PVC) is the most widely used chlorine polymer as wire insulation and is therefore preferred in the present invention. PVC is a homopolymer of vinyl chloride or a copolymer of vinyl chloride with a small amount (eg, up to 20% by weight) of another copolymerizable comonomer (eg, vinyl acetate or ethylene) that does not alter the essential properties of the homopolymer. Can be PVC is typically about 80
It has a glass transition temperature (Tg) of 100 ° C and is usually itself melt processed at a temperature of 180-200 ° C. Polyvinylidene chloride has a high melt processing temperature but is slightly less temperature stable than PVC. According to the present invention (where other polymer components are present), the halide polymer can withstand high melt processing temperatures for a limited period of time, at which time the halide polymer is clearly recognized or Sufficient time to achieve melt blending without detectable degradation.

[0021] The polyamide component is a component that can be melt processed at a temperature below about 220 ° C. Some polyamides can be melt processed at temperatures below about 200 ° C. The melt processing temperature of the polyamide is the temperature at which the viscosity of the polyamide is low enough that the polyamide can deform and compress into a single, essentially void-free mass. This is not a specific melt viscosity, but a melt viscosity range in which these results can be obtained, which allows for performing melt processing of the composition of the present invention. In the case of crystalline polyamides, this viscosity is achieved by melt processing temperatures above the melting point (measured by differential scanning calorimetry (DSC)). In the case of an amorphous polyamide, which may also include a crystalline polyamide phase, this viscosity is achieved at a temperature above the Tg of the polyamide, at which temperature the polyamide imparts the desired viscosity for melt blending Softens sufficiently. This relatively low melt processing temperature of the polyamide used in the present invention opens the door to the possibility of melt blending the halide polymer with the polyamide without undergoing decomposition. Polyhexamethylene adipamide (nylon 66), the most common polyamide melting at 255 ° C,
Cannot be used due to its high melting point. Examples of polyamides having a sufficiently low melt processing temperature are polydodecamethylene dodecanoamide (nylon 1212) with a melting point of 184 ° C, polycaprolactam (nylon 6) with a melting point of about 215 ° C, 18
Polydodecanolactam (nylon 12) that melts at 0 ° C,
Polyhexamethylene dodecanoamide (nylon 6,12) melting at 210 ° C, polydecamethylene sebacamide (nylon 10,10) melting at 216 ° C, polyundecanoamide (nylon 11) melting at 185 ° C, Poly 2-methylpentamethylene adipamide (MPMD, 6) melting at 180 ° C, 16
Poly 2-methylpentamethylene dodecanoamide (MPMD, 12) melting at 0 ° C, and polyhexamethylene sebacamide (nylon 6,10) melting at 215 ° C, and two bases such as adipic acid and isophthalic acid An amorphous polyamide produced by copolymerization (condensation polymerization) of a mixture of an acid and hexamethylenediamine is exemplified.

In spite of the fact that some of these polyamides have a higher melting point compared to the halide polymers, the halide polymers are not subject to decomposition and can be combined together at the high melt processing temperatures required for the polyamides. It has been found that melt blending is possible.

The third component of the melt blend, a functionalized ethylene polymer, promotes melt blending due to its presence in the melt blend. This allows
The ability of the halide polymer and the polyamide to completely disperse with each other without appreciable degradation of the halide polymer is improved. Ethylene polymers also help intimately mix other polymer components by reducing the melt viscosity of the melt blend.

Preferably, the ethylene polymer is miscible with the halide polymer during the melt blending process, so that under a microscope, the melt blend (under cooling) will have two visible phases, namely a hydride polymer phase. It only has a polyamide phase. When the halide polymer and the polyamide are present in approximately equal amounts, it is the complete blend of the continuous phase of these polymers that results from the melt blending, otherwise, the melt blending produces only the higher amount. Fine dispersion of the other polymer in the matrix of the polymer. The miscibility of the ethylene polymer with the halide polymer depends on the halide polymer as a matrix or continuous phase, depending on the amount of ethylene polymer present, even if the amount of polyamide is somewhat greater than the amount of halide polymer. Promote.

[0025] The effect of compatibilization of the ethylene polymer is the close, essentially void-free contact between the halide polymer phase and the polyamide phase of the melt blend, and consequently of the product fabricated therefrom. , And higher toughness than either the halide or polyamide components.

The ethylene polymer is compatibilized with the carboxyl or carbon monoxide functionality of the ethylene polymer to effect the interaction with the halide polymer and the polyamide;
By preferably mixing, a part of the compatibilizing effect is achieved. It is believed that the carboxyl (COO-) and carbon monoxide functionality are covalent and hydrogen bonded to the polyamide, respectively. Preferably, the ethylene polymer is
It has both a carboxyl group and a carbon monoxide group.

Examples of carboxyl-functionalized ethylene polymers include copolymers of ethylene and C ₃ -C ₁₂ ethylenically unsaturated monocarboxylic acids, C ₁ -C ₁₈ alkyl of ethylenically unsaturated C ₃ -C ₁₂ monocarboxylic acids. Esters and vinyl esters of C ₃ -C ₁₈ saturated carboxylic acids. More specific examples include ethylene / vinyl acetate copolymers, ethylene / vinyl acetate copolymers.
An alkyl (meth) acrylic acid copolymer (provided that the alkyl group has 1 to 8 carbon atoms). Such ethylene polymers include copolymers of ethylene with methyl acrylate, propyl acrylate, n-butyl acrylate, hexyl acrylate or n-butyl acrylate and / or the corresponding free acid. For these polymers, the proportion of ethylene is 10
Usually about 30 to 60% by weight, based on 0% by weight, wherein the carboxyl functionality is about 40 to 70% by weight.

Preferably, the ethylene polymer is also functionalized with carbon monoxide, so that the small amount of acetate, acrylate or acrylate comonomer used is combined with the polyamide required for compatibilization. Hydrogen bond can be obtained. A preferred such polymer is an ethylene / alkyl (meth) acrylate / carbon monoxide copolymer, where the alkyl group can have the same meaning as described above. Ethylene / vinyl acetate / carbon copolymers are also preferred. Generally, for these copolymers, the proportion of ethylene is about 50-70% by weight, based on 100% by weight of the total ethylene polymer, and the acid,
The ratio of acrylate or acetate is about 24 ~
40% by weight and the proportion of carbon monoxide is about 5 to 15% by weight.

[0029] The ethylene carboxyl and / or carbon monoxide functional copolymer is also preferably modified with an anhydride (ie, containing carboxylic anhydride groups pendent to the polymer backbone). Anhydride modification is typically accomplished by grafting the preformed copolymer with maleic acid or maleic anhydride to form succinic anhydride groups on the copolymer by conventional procedures. . Typically, the amount of anhydride modification is from about 0.1 to 5% by weight, based on the weight of the copolymer. The most preferred ethylene polymer is an ethylene / alkyl acrylate / carbon monoxide copolymer modified with succinic anhydride, wherein the alkyl group has 1 to 4 carbon atoms, and preferably n-butyl acrylate. .

Modification of the functionalized ethylene polymer with an anhydride results in good bonding to the polyamide phase, which is believed to be caused by a chemical reaction between the anhydride groups and the polyamide.

The melt blending of the three components can be carried out using a conventional apparatus such as an extruder or an extrusion screw of an injection molding machine. Preferably, these components are pre-blended, for example, by dry mixing with the halide polymer (in powder form) using typical halide polymer stabilizers. Subsequently, the stabilized halide polymer powder is melt-blended with polyamide and ethylene polymer. The polyamide and ethylene polymer are typically in the form of shaped granules.
Conventional additives, such as antioxidants, can also be present in the melt blend.

[0032] Melt blending is typically performed in conventional plastic melt compounding equipment such as batch mixers, twin screw extruders and single screw kneaders (kneaders).

The melt blends of the compositions of the present invention can be prepared by conventional methods (eg, extrusion and injection molding) by wire coating, tube, pipe (tube) inner,
It can be melt fabricated into a wide variety of products, such as sheets, films, and molded products (eg, containers).

[0034]

EXAMPLES In the following examples of the present invention, parts and percentages are by weight unless otherwise indicated.

Example 1 In a series of experiments included in this example, the PV used was
C is the internal viscosity of 0.74 (ASTM1243 method) and Tg of about 80 ° C
VISTA5305 having the following formula: This PVC powder is combined with the following stabilizer: 2.7% butyl tin mercaptin (butyl ti
n mercaptin) (MARK 1900), 0.9% thioester (SEENOX 412S) and 0.9% hindered phenol (IRGANOX 1098) in a powder mixer (WELEX). This PVC powder mixture is further combined with a wax release agent (HOECHST WAX E) 2.7% and a flame retardant additive (THER
MOGUARD CPA) 4.4% was added. All figures are PV
C:% by weight based on the total weight of the powder blend. The polyamide used is available as RILSAN AESNO TL
Nylon 12 with a melting point of 180 ° C. Ethylene polymer is 60% by weight ethylene and 30% by weight acrylic n
-Butyl acrylate, 10% by weight of which is grafted with 0.9% by weight of succinic anhydride groups, carbon monoxide, available as FUSABOND MG-175D.

The composition was prepared in a 46 mm Buss Kneader with a length to diameter ratio of 16: 1.
The kneader is equipped with two feeds, the first feed being at the upstream end of the machine as usual and the second feed from the first feed about 1/2 of the device. It is located downstream about 8 times the distance or diameter. Nylon pellets and ethylene polymer pellets were fed together through a first feed, and a PVC powder blend was fed through a second feed.

The production rate of the final composition is about 50 per hour.
The ingredients were weighed to the pound. The temperature of the molten polymer component was controlled by the kneader barrel heater and screw speed (RPM). The set point temperature between the first and second feeds was set at a downhill temperature profile starting at about 275 ° C and decreasing to about 170 ° C. This facilitates rapid melting and homogenization of the nylon and ethylene polymer added to the first supply port.

The melt was also cooled sufficiently to about 180 ° C. until it reached the second feed port. This allowed the PVC powder blend to be safely introduced from the second supply port without exposing the heat sensitive PVC to excessive temperatures. The remaining kneader length was heated to about 150 ° C. and the resulting homogeneous ternary polymer blend was developed at a melting temperature below 200 ° C. or not exceeding 200 ° C.

The screw speed is typically 310 RPM,
The screw temperature was 150 ° C.

The molten blend discharged from the kneader is
It was introduced into a low-shear, relatively cool (about 約 160 ° C.) single-screw extruder, which pumps the melt through a four-hole die. The strands of the resulting blend were quenched in a water bath and then cut into pellets.

Table 1 shows that polyamide (nylon 12) in a blend of PVC with an ethylene copolymer compatibilizer.
) Shows the results when the level was gradually increased.

The test pieces were compression molded from the pellets on a bath kneader. The tensile strength, elongation, and resistance to fuel C were measured (Table 1).

[0043] Table 1 A B C D PVC 56.2 47.0 38.0 27.6 Nylon 12 18.7 23.5 38.0 55.1 ethylene polymer 18.7 23.5 19.1 13.8 stabilizers and additives 6.4 6.0 4.9 3.5 Fuel C, 7 days volume swell (%) 39 44 31 6.3 Residual rate of tensile strength (%) 56 50 56 92 Residual rate of elongation rate (%) 192 87 51 83 Initial tensile strength (MPa) 20.8 19.1 26.1 30.7 Initial elongation rate (%) 131 274 353 316 Approx. At the following polyamide levels (samples AC), the chemically aggre
It is very evident that the swelling of fuel S in fuel C exceeds 30%. Simultaneously with this volume increase, a decrease in tensile strength of about 40% or more occurs. In contrast, the polyamide level of 57% (based on the whole polymer), ie PV
At the polyamide level of twice the weight of C 2, the volume swell is only 6% and the tensile strength is reduced by only 8%,
Chemical resistance has also been improved by a factor of five.

Table 3 I J PVC 27.9% 21.7% Nylon MPMD, 12 55.7% 65.4% EnBACO-g-MAH 13.9% 10.9% Stabilizer and additives 2.5% 2.0% Tensile strength at break, MPa 39.3 29.6 at break Elongation,% 312 250 Notched Izod, J / m No break 320 Fuel C, 7 days Volume swelling (%) 2.5-Residual tensile strength (%) 106-Residual elongation (%) 100-Table From Table 3, the tensile strength at break, the elongation and the notched Izod impact strength were measured in Sample I (in this sample, the polyamide was twice as much (weight) as the amount (weight) of the halide polymer).
Is better. Percent volume swell and residual tensile strength were also exceptional. In sample J, the polyamide is present in an amount (weight) that is three times the amount (weight) of the halide polymer. Sample J was not further tested as unacceptable tensile strength (ie, 30 MPa or less), elongation, and notched Izod results were obtained.

Example 2 In a series of experiments included in this example, the PV used was
C is an internal viscosity of 0.68 (ASTM1243 method) and a Tg of about 80 ° C.
VISTA5265 having the following formula: This PVC powder is combined with the following stabilizer: 3.7% butyltin mercaptin (MARK 190
0), 1.0% thioester (SEENOX 412S) and 1.
Blended with 0% hindered phenol (IRGANOX 1098) in a powder mixer (WELEX). To this PVC powder mixture, a wax release agent (HOECHST WAX E) 2.8 was added.
% Was added. All figures are percentages by weight based on the total weight of the PVC powder blend.

The composition was prepared by adding the ethylene copolymer, polyamide (dried) to a Haake 90 mixer. The set temperature of the mixer is 18
The temperature was set to 0 ° C., and the number of revolutions (rpm) was set to 50. After all ingredients have been added (less than 1 minute), the mixer temperature is increased to 205 ° C.
And the number of revolutions (rpm) was increased to 200. Mixing was continued until the mixture melted homogeneously, which occurred in about 8 minutes at about 200 ° C. Next, the set temperature was reduced to 185 ° C., and the number of revolutions (rpm) was reduced to 75. The mixture temperature was reduced to about 205 ° C (about 3 minutes). The PVC was then added and the composition was mixed for about 5 minutes or until uniformity was found.
During this time, the temperature was adjusted to 205 by adjusting the rotation speed (rpm).
C. or less. The sample was taken out and quenched with dry ice. A test piece was compression molded from a composition prepared with a Haake mixer, and the notched Izod impact strength, elongation,
The tensile strength and resistance to fuel C were tested.

[0047] Table 2 E F G H PVC 27.9 32.4 27.9 32.4 Nylon 12 55.7 48.5 nylon MPMD, 6 55.7 48.5 ethylene polymer 13.9 16.2 13.9 16.2 stabilizers & additives 2.5 2.9 2.5 2.9 Fuel C, 7 days volume swell (%) 12 18 6.2 16 Residual rate of tensile strength (%) 79 65 84 75 Residual rate of elongation rate (%) 114 106 125 112 Initial tensile strength (MPa) 47.2 46.6 42.3 39.9 Initial elongation rate (%) 262 273 275 298 Notched Izod, J / m No break No break
No break No break Samples G and H (Table 2)
It is clear that MPMD, 6 is also very resistant to Fuel C, equal to or higher than the comparative blend of Nylon 12 (Samples E and F). These blends, consisting of about 50% (or more) polyamide, have a fuel C volume swell value of less than 20% and retain a tensile strength of greater than about 65%. These compositions prove to be very tough as indicated by the absence of breakage as measured by the notched Izod test.

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Claims (5)

[Claims] A composition comprising a vinyl or vinylidene halide polymer, a polyamide, and an ethylene polymer having carbon monoxide and / or carboxyl functionality for compatibilizing the halide polymer and the polyamide during melt blending. Wherein the polyamide is present in an amount (weight) of about 1.5 to about 2 times the amount (weight) of the halide polymer, and the ethylene polymer is present in an effective amount of up to about 80% by weight of the halide polymer. A composition characterized in that it is present. 2. The composition of claim 1 wherein said polyamide is present in an amount (weight) of about 1.75 to about 2 times the weight (weight) of said halide polymer. 3. The composition according to claim 1, wherein said halide polymer is polyvinyl chloride. 4. The composition according to claim 1, wherein said polyamide is nylon MPMD, 6 or nylon MPMD, 12. 5. A structure comprising a coating of the composition of claim 1 on a wire substrate.