JPH0361695B2 - - Google Patents

Description

[Detailed description of the invention]

Blends of ethylene copolymers and halogenated vinyl polymers that are crosslinked during or after shaping into shaped articles are known, as detailed in French Patent No. 2,148,496. However, molded articles produced from these compositions have the disadvantage that they are thermosetting due to the high degree of crosslinking that occurs and therefore cannot be reprocessed or remolded. Elastomeric thermoplastic compositions based on partially crosslinked incompatible blends of polypropylene and ethylene/vinyl acetate copolymers are also known, as detailed in US Pat. No. 4,232,132.
This incompatibility results in a multiphase system consisting of a crosslinked elastomeric phase and a non-crosslinked hard phase. However, the elastomeric properties (eg, % permanent elongation) of these compositions are inferior compared to the compositions of the present invention. The present invention relates to thermoplastic, essentially melt-processable elastomeric compositions based on partially crosslinked compatible blends of ethylene copolymers and vinyl halide or vinylidene polymers. The melt processability of these compositions allows molded articles to be formed therefrom without the need for the time-consuming vulcanization steps required in conventional rubbers. More particularly, the present invention provides (a) 95 to 25 weight percent ethylene and one or more ethylenically unsaturated organic monomers selected from the group consisting of carbon monoxide and sulfur dioxide, based on the blend; and (b) from 5 to 75 weight percent, based on the blend, of a vinyl halide or vinylidene polymer, wherein the comonomer content is such that the copolymer is a vinyl halide or vinylidene polymer. An amount such as to represent compatibility with the copolymer, except that if the copolymer is a binary copolymer of ethylene and an organic monomer, the organic monomer content is 45% by weight based on the weight of the copolymer. Thermoplastic elastomer compositions consisting of partially crosslinked blends of greater than 50%. Ethylene copolymers useful in the practice of this invention include, for example, bipolymers having the formulas E/X and E/Y, and terpolymers having the formula E/X/Y, where X is an ethylenically unsaturated organic monomer and Y is carbon monoxide or sulfur dioxide. Examples of organic monomers are unsaturated mono- or dicarboxylic acids of 3 to 20 carbon atoms, acid groups of 2 to 18
Vinyl esters of saturated carboxylic acids having carbon atoms, vinyl alkyl ethers in which the alkyl group has 1 to 18 carbon atoms, vinyl halides or vinylidene, acrylonitrile, methacrylonitrile, norbornene, 3 to 12 carbon atoms alphaolefins, and vinyl aromatic compounds. Suitable organic monomers include methyl acrylate, butyl acrylate and vinyl acetate. Of course, more than one of these organic monomers can be copolymerized with ethylene to produce ethylene copolymers useful in the practice of this invention. The melt index range for these copolymers is 0.1
~1000 (ASTM D-1238), preferably 1-100
It is. Ethylene copolymers useful in the practice of this invention must be copolymerized with sufficient comonomer to exhibit compatibility with vinyl halide and vinylidene polymers, as described below. Generally speaking, when an ethylene copolymer is represented by the formula E/X, interpolymers having a comonomer content greater than 45 percent based on the weight of the copolymer are useful in the practice of the present invention; and When an ethylene copolymer is represented by the formula E/X/Y, a substantially lower comonomer content indicates compatibility with vinyl halide and vinylidene polymers, i.e., both based on the weight of the polymer. The ethylene content in these terpolymers ranges from 40 to 85 percent;
The organic monomer content can be from 1 to 60 percent and the carbon monoxide or sulfur dioxide content from 1 to 30 percent. E/X type copolymers require such a high comonomer content compared to E/X/Y type copolymers in order to exhibit compatibility with vinyl halide or vinylidene polymers. Therefore, for the purpose of the present invention, these E/
Particularly preferred are copolymers of the X/Y type. When using ethylene copolymers that are not sufficiently compatible with vinyl halide or vinylidene polymers, molded articles molded from the blend are opaque, exhibit stress whitening when stretched, and are considered elastomers. lacks the necessary recovery. A more detailed explanation of the compatibility of these ethylene copolymers with halogenated vinyl and vinylidene polymers, as well as a discussion of the preparation of the copolymers, can be found in "Polymer-Polymer Mixability", O. Olabisi. ,
Robeson (LMRobeson) and Schillot (MT
Show), Academic Press New York,
New York, 1979, US Pat. No. 3,684,778 and US Pat. No. 3,780,140. 5 to 75, preferably based on the blended composition according to the invention, of the above ethylene copolymers.
Blend with 20 to 60 weight percent of vinyl halide or vinylidene polymers, including the group consisting of vinyl esters, acrylonitrile, acrylic esters, vinylidene chloride, vinyl chloride, esters of unsaturated carboxylic acids, and vinyl ethers. This includes those produced by copolymerization with comonomers selected from Polyvinyl chloride having an inherent viscosity (ASTM D-1243) of, for example, 0.30 to 1.4 is generally useful in the practice of this invention. Blending of the ethylene copolymer and the vinyl halide or vinylidene polymer may be carried out by any of a number of conventional methods, for example using a Banbury mixer, a two roll mill or an extruder. I can do it. For proper blending, this blending is carried out at a temperature high enough to soften the polymer, but not so high as to degrade the vinyl halide or vinylidene polymer. Generally, the blending temperature is in the range of 140-200°C and the blending is carried out for a sufficient time to uniformly mix both components. An important feature of the invention is the partial crosslinking of compatible blends. This can be accomplished using one or more of the known crosslinking methods including electron beam irradiation, gamma irradiation and free radical vulcanizing agents such as peroxides. Crosslinking of the polymer blends of the invention may be carried out prior to or simultaneously with blending with vinyl halide or vinylidene polymers, or after such blending if crosslinking is achieved using radiation methods. be able to. If the ethylene copolymer in the blend contains carbon monoxide, diamines such as methylene dianiline or p-phenylene diamine can be used to achieve the desired crosslinking. When the ethylene copolymer is ethylene/vinyl acetate/carbon monoxide, a sulfur vulcanizing agent can be used, as detailed in US Pat. No. 4,172,939. For crosslinking of ethylene copolymers with carboxylic acid functionality, ionic crosslinking is suitable in the practice of the invention, and various metal oxides or hydroxides, such as ZnO and NaOH, are used. or using Arii metal compounds such as chromium acetylacetone, as detailed in US Pat. No. 4,304,887. The term "partially crosslinked" refers to the conversion of blends of ethylene copolymers and vinyl halide or vinylidene polymers, as detailed above, into thermoplastic elastomeric blends of the present invention. A sufficient degree of crosslinking is meant. To quantify the degree of crosslinking, a sample of the crosslinked polymer must be heated at 23°C.
The undissolved material, i.e. the cross-linked heavy Measure the amount of coalescence. Subtract the weight of components soluble in tetrahydrofuran, such as plasticizers, from the initial weight, and subtract components insoluble in tetrahydrofuran, such as pigments, fillers, etc., from both the initial and final weights. Pull. Record the recovered insoluble polymer as percent gel content. This method is based on conventional methods for quantifying the degree of crosslinking, which are more fully detailed in US Pat. No. 3,203,937. For purposes of the present invention, the polymer blend is partially crosslinked so as to have a gel content of 5 to 90 percent, preferably 10 to 70 percent, based on total polymer. It is necessary. The conditions for carrying out such crosslinking, ie, the type and amount of crosslinking agent, crosslinking time and temperature, to arrive at a composition with a gel content within this practical range can be determined empirically. If a chemical crosslinking agent is used, it is preferred that it be substantially consumed during the crosslinking process. When polyvinyl chloride (PVC) is used as the vinyl halide polymer in the practice of this invention, spectroscopic evidence indicates that the gel fraction separated from the partially crosslinked polymer blend is a crosslinked ethylene copolymer. Contains only coalescence and can be detected
Indicates that PVC is not present. Therefore,
It is theorized that essentially no crosslinking of the PVC occurs. Although not essential ingredients of the compositions of the present invention, various amounts of a number of conventional fillers or compounding agents can be mixed. Examples of such ingredients are various carbon blacks, clays, silica, alumina, calcium carbonate, titanium dioxide, antioxidants, antidegradants, tackifiers, processing aids such as lubricants and waxes, and , processing aids such as dialkyl phthalates, trialkyl phthalates, and polyester oligomers. The amount used depends, at least in part, on the nature of the other ingredients in the composition and the properties desired for the composition. Additionally, the cost or properties of the composition can be reduced by adding relatively small amounts of other saturated and unsaturated polymers, such as alpha-olefins. The compositions of this invention can be melt processed using conventional plastics processing equipment. Articles molded from our unique thermoplastic elastomer composition exhibit properties generally associated only with vulcanized rubber. For example, these compositions have resistance to compression set of about 20 to 70 percent (70 to 100°C); and elongation at break of 150 to 600 percent without substantial permanent elongation (i.e., less than about 15 percent). have. Various uses for these compositions include wire coatings, seals and gaskets, automotive parts, seat backings, and packaging films. These compositions can be used to coat textiles, industrial belts and various hard surfaces such as polyester, polyamide, polyimide or metal fibers or textile reinforcements by extrusion coating. They find use in adhesives and sealants, and for the modification of other polymeric systems. Additionally, compositions within the scope of the invention may be used for laboratory use,
It can be processed into tubes for medical and industrial use. Such a tube can also be used as the inner tube of a reinforced hose, in which case it may be applied as a spiral to the extruded tube, or
Cover with braided or braided wire or fiber cord. In some cases, a polymeric coating may be applied over the reinforced tube (extruded or spiral-wound calender sheet) to provide protection from working environment and mechanical abuse. Compositions within the scope of the invention can be used as protective coatings for reinforced tubes of similar or different compositions. The invention may be understood in more detail with reference to the following examples. Example 1 Unless otherwise indicated, the percentages given in all examples herein are based on weight percent. The intrinsic viscosity (iv) given for polyvinyl chloride (PVC) is determined at 25° C. on a solution of 0.2 g of polymer in 100 ml of cyclohexane. The melt index (MI) of ethylene copolymers is measured at 190°C according to ASTM D-1238. The following formulations were blended as follows.
Due to its thermal instability, PVC was dry mixed with the following stabilizer package (percentages based on the weight of PVC) as is typical in PVC formulations: Ingredients % "Marked" from Argus Chemical Company Ba/Cd laurate available as WS 2.5 “Paraplex” from Rohmendhaas
Epoxidized soybean oil available as G62 8.2 Liquid phosphite chelator available as “Mark” 517 from Argus Chemical Company 0.8 “Acryloid” from Rohm and Haas Company
Acrylic melting aid available as K120N
2.5 Polyethylene wax available as "Allied" 6A from Allied Chemical Company 3.3 Stearic acid 0.3 Batches A, B and C were blended in a Banbury internal mixer for 6 minutes at 180°C and then dried on a conventional two roll machine. I separated it out. Batch E is 200℃
The mixture was blended in a 28 mm twin-screw co-rotating self-wiping extruder with a barrel temperature of 10 Kg/hr, using a final extrusion rate of 10 Kg/hr. The blended composition is discharged from the extruder through a strand die,
Cut into 0.5 cm (3/16 inch) pellets.
Batches D and F are heated at 160-170℃ after crosslinking as described below.
Batch C and E were prepared directly from batches C and E, respectively, by addition of carbon black on a two-roll rubber roll machine. Ethylene copolymer/
Electron beam crosslinking of the PVC blends was carried out at room temperature under atmospheric conditions with a high energy electron beam (dose rate, 3.0 Mrad/min) using a 2 MeV general electric resonance transformer at 0.3 mA. The dose was adjusted by the time the blend was irradiated. Blend is 15cm x 15
In the form of cm x 0.3 cm (6" x 6" x 1/8") flat plates (batches C and D) or as a layer of 0.5 cm (3/16") pellets (batches A, B, E and F). ). The degree of crosslinking was monitored by observing the change in melt index as the dose was increased. Irradiation was stopped when the melt index approached or reached no flow (no measurable melt index).

【table】

Table: After blending and crosslinking, each batch was placed in a mold at room temperature and heated to 200°C to demonstrate that these compositions were melt processable.
Pressure was applied in a Pasadena hydraulic press with upper and lower heating platens preheated to . Pressure about 1.3MPa (200psig)
and held for 5 minutes. The pressure was then gradually increased to 276 MPa (40,000 psig) over a period of 3 minutes, and then
I kept it for a minute. The press was then rapidly cooled to room temperature and the molded product was removed. The results of physical property measurements made on each sample are shown in the table below and indicate that these samples exhibit the properties of vulcanized rubber. The molded product could be melt processed again.

Table: Example 2 The following formulations were blended as follows (numbers are in weight percentages and the PVC was stabilized as in Example 1):

【table】

【table】

Table: Batches A and B were blended by adding all ingredients except the vulcanizing agent to a Banbury internal mixer at 150°C for 7.0 minutes. The crosslinking agent was then added with high speed mixing followed by partial crosslinking by raising the temperature to 190°C and holding at that temperature for 4 minutes. Then apply the composition to 0.6 cm (1/
The compositions were extruded into tubes at 190°C using a Brabender extruder equipped with a 4" tubing die. Thereby, these compositions were shown to have thermoplastic processability. Blends can also be readily injection molded at high speeds, as exemplified by the following method: The composition is heated to 170°C in all areas of the barrel and the mold is heated to 25°C. Using a screw rotation speed of 144 revolutions per minute and an injection pressure of 1200 psi, the molten material was charged into the flat mold cavity in 15 seconds, followed by 10 seconds. After cooling for a few seconds, the mold was opened and the finished product was injected. Batch C was blended in a Herkeleocord test mixer as follows: PVC and E/
The MA polymer was added into the mixer at 145 °C and at high speed (64
The temperature was raised to 180° C. and held for 2 minutes while mixing at a rotational speed of 180° C. (rpm/min). After the blend was allowed to cool to below 125°C, the crosslinker was added. The temperature was increased to 180°C while mixing at high speed and the mixture was held at temperature for about 2 minutes to allow partial crosslinking to occur. Batch D is 28mm with barrel temperature of 200℃
from beginning to end in a twin-screw co-rotating self-wiping extruder.
It was prepared by blending PVC and ethylene polymer using an extrusion rate of 10Kg/hour. The blended composition was discharged from the extruder through a strand die and cut into 0.5 cm (3/16 inch) pellets. Partial crosslinking is achieved using Brabender test mixture (Plasticord) as follows:
The polymer blend was added to the mixer and the temperature was stabilized at 110 °C at low speed (32 revolutions/min), then the crosslinker was added and the mixing was increased to high speed (64 rpm).
Raise the temperature to 155 °C while mixing at
After keeping it for 15 minutes, it was removed. Batch E was prepared in a Banbury mixer at 180°C.
Blend for a minute. The blend was then transferred into a Brabender mixer (Plasticord) and the crosslinker was added. The mixture was held in a mixer at 170°C for 5 minutes to allow crosslinking to occur. Samples of each batch were compression molded as in Example 1. The physical properties of the molded product are shown in the table below.

Table Example 3 To illustrate the use of other crosslinking agents, the following formulation was used: wt% E/30% n-BA/10% CO 54 PVC ¹ 29 Dioctyl phthalate 16.6 LiCl.3MDA ² 0.4 1 “Thermolite” from M&T Chemicals
PVC stabilized with 2PHR tin thioglycolate available as 133 2 Complex of lithium chloride and 4,4'-diaminodiphenylmethane E/n-BA/CO melted at 190 °C
Add slowly to the PVC and mix the composition uniformly on a two roll mill. Then dioctyl phthalate and
LiCl.3MDA was added and the composition was kneaded at 190°C for 5 minutes. The composition was then removed from the roll and compression molded into a flat plate. Its physical properties are shown in the table below. Compressive strain B (%) ¹ 22.5 Volumetric expansion (%) 36.2 1 22 hours at 70°C Example 4 This example is to demonstrate the effect of crosslinker concentration on gel content. In these formulations, stabilized PVC ¹ was first mixed with trioctyl trimellitate in a dry blending operation. The entire formulation was then blended and simultaneously crosslinked in a 28 mm twin screw co-rotating, self-wiping extruder as in Example 1. The degree of crosslinking was determined by measuring the percent gel content in tetrahydrofuran (16 hours, 23°C) as described above. Sample A, which contains no vulcanizing agent and therefore is not crosslinked, contains only traces of gel (insoluble matter). All samples were compression molded as in Example 1.

Table The usefulness of the compositions of the present invention in many aspects is illustrated below: Profile Extrusion Batch C of Example 4 in the form of pellets was prepared in 15:
The sample was fed into a 1 1/2 inch (4.8 cm) diameter Royle extruder with a single stage plastic shaft having a length:diameter ratio of 1. Extruder at 50 rpm, 130
It was operated at temperatures designed to give melt temperatures of 163-170°C and 180-193°C. 3
The entire temperature range was extruded through a feathered edge profile die known as a Garvey die. The profile extrusion experiments described above demonstrate that compositions within the scope of the present invention can be manufactured into complex profiles at relatively low melt temperatures using standard extruders with length/diameter ratios common to the rubber industry. This shows that it can be extruded as Such extruded profiles can be used as gaskets or various mechanical parts. Continuous Extrusion Coating of Metal Wire Formulation C of Example 4 cut into pellets or granules was coated with a 1 1/4 inch (3.2 cm) diameter Brabender extruder. This extruder has a melt temperature of 197℃ and a temperature of 20~100℃.
At a speed of feet (0.6-30m)/min
It has a crosshead die sized to provide a 0.050 inch (0.13 cm) thick coating on 12 AWG aluminum wire. The metal wire coating tests described above and the physical and electrical properties measured thereafter indicate that compositions within the scope of the present invention can be used as coatings, either as low voltage primary insulation or as armor or semiconductive coatings in high voltage structures. It shows that it can be used for the production of electric wires and cables. Rolled and calendered sheet Formulation C of Example 4 in pellet form at 1.2:1
It was kneaded and banded on an 8 x 20 inch (0.2-0.5 m) two-roll rubber roll machine with a roll surface speed ratio of .
270〓 (132℃) of band-shaped polymer from a roll machine
The kneaded product was cut at a temperature of 100 mL and transferred to a three-roll rubber calender. All 3 rolls from 260 yen
Thickness by keeping at 275〓(127~135℃)
A reasonably smooth sheet of 0.015 cm (0.04 cm) was produced that peeled easily when cut from the central calendar roll. Similar results were obtained when 20 phr vaporized silica and 100 phr dioctyl sebacate were incorporated into the polymer band on a rubber roll machine prior to calendering. The above roll kneading and calendering tests are
It has been shown that compositions within the scope of the present invention can be melted and further compounded on a rubber roll machine and then processed into sheets on a standard rubber calender using moderate processing temperatures. . The sheets produced in this way can be used without support as elastomeric packaging films, or on textiles or for roofing materials, hole and pond covers, stamped gaskets, diaphragms, conveyor belts and for general use. Calendering can be carried out onto fabrics or onto webs of one or more layers of reinforcing cord for use in coated textile applications.

Claims (1)

Claims: 1. (a) Based on the blend, 95 to 25 percent by weight of ethylene and one or more co-organic monomers selected from the group consisting of ethylenically unsaturated organic monomers, carbon monoxide and sulfur dioxide; a copolymer of a polymerizable comonomer; and (b) from 5 to 75 weight percent, based on the blend, of a vinyl halide or vinylidene polymer, where the comonomer content in (a) is such that the ethylene copolymer is in an amount compatible with the vinyl halide or vinylidene polymer, provided that if the copolymer is a binary copolymer of ethylene and an organic monomer, the organic monomer content is based on the weight of the copolymer. Partially crosslinked blends having a weight percent greater than 45. 2. Patents containing one or more members of the group consisting of carbon black, clay, silica, alumina, calcium carbonate, titanium dioxide, dialkyl phthalates, trialkyl mellitates, polyester oligomers and saturated and unsaturated polymers. A blend according to claim 1. 3. The blend of claim 1 having a gel content of 5 to 90 percent based on total polymer weight. 4. The blend of claim 1 having a gel content of 10 to 70 percent based on total polymer weight. 5. The blend of claim 1 having a gel content of 20 to 40 percent based on total polymer weight. 6. The blend of claim 1, wherein (b) is polyvinyl chloride. 7. The blend according to claim 2, wherein (b) is polyvinyl chloride. 8. The blend of claim 3, wherein (b) is polyvinyl chloride. 9. The blend of claim 4, wherein (b) is polyvinyl chloride. 10. The blend of claim 5, wherein (b) is polyvinyl chloride. 11 Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, wherein the copolymer (a) is a copolymer of ethylene and an ethylenically unsaturated organic monomer.
Blends listed in section. 12 Organic monomers include unsaturated mono- or carboxylic acids having 3 to 20 carbon atoms, esters of such unsaturated mono- or dicarboxylic acids, vinyl esters of saturated carboxylic acids whose acid group has 2 to 18 carbon atoms, and alkyl groups. Claims selected from the group consisting of vinyl alkyl ethers having 1 to 18 carbon atoms, vinyl or vinylidene halides, acrylonitrile, methacrylonitrile, norbornene, alphaolefins having 3 to 12 carbon atoms, and vinyl aromatics. The blend according to item 11. 13. The blend of claim 11, wherein the organic monomer is selected from the group consisting of methyl acrylate, butyl acrylate, vinyl acetate, and maleic acid monoethyl ester. 14. Claims 1, 2, 3, 4 and 5, wherein the copolymer (a) comprises ethylene, a copolymerizable ethylenically unsaturated organic monomer, and a member of the group consisting of carbon monoxide and sulfur dioxide. ,6,7,8,
The blend according to item 9 or 10. 15 The organic monomer is an unsaturated mono- or dicarboxylic acid having 3 to 20 carbon atoms, an ester of the unsaturated mono- or dicarboxylic acid, a vinyl ester of a saturated carboxylic acid having an acid group of 2 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms. selected from the group consisting of vinyl alkyl ethers having carbon atoms, vinyl halides or vinylidene, acrylonitrile, methacrylonitrile, norbornene, alpha olefins having 3 to 12 carbon atoms and vinyl aromatic compounds. Blend according to item 14. 16. The blend of claim 14, wherein the organic monomer is selected from the group consisting of methyl acrylate, butyl acrylate, and vinyl acetate. 17 Organic monomers range from 1 to 60 based on the copolymer.
carbon monoxide or sulfur dioxide is present in the copolymer in an amount of 1% by weight based on the copolymer.
15. The blend of claim 14, wherein the blend is present in an amount of ~30 weight percent. 18 Organic monomers range from 1 to 60 based on the copolymer.
carbon monoxide or sulfur dioxide is present in the copolymer in an amount of 1% by weight based on the copolymer.
16. The blend of claim 15, wherein the blend is present in an amount of ~30 weight percent. 19 Claims 1, 2, 3, 4, 5, wherein the copolymer (a) is a copolymer of a member of the group consisting of ethylene, carbon monoxide, and sulfur dioxide.
The blend according to item 6, 7, 8, 9 or 10. 20. The blend of claim 19, wherein the carbon monoxide or sulfur dioxide is present in the copolymer in an amount greater than 15 weight percent based on the copolymer.