JPS6343405B2 - - Google Patents

Description

[Detailed description of the invention]

Summary of the invention The present invention relates to a method for modifying an ethylene polymer,
Specific density of approximately 0.87 to approximately 0.93gr./cc and approximately
A particulate ethylene polymer having a pore volume of 0.1 to about 1 c.c./gr. is reacted with a gaseous chlorosulfonating agent in the absence of a solvent or diluent to a pressure of about 2000 psi.
This type of modification process produces particulate elastomerol sulfonated polymers having a tensile modulus of less than (141 Kg/cm ² ) and a crystallinity of less than about 10%. The elastomeric polymers thus produced can be cured into crosslinked products useful in the manufacture of film materials such as extrusion coatings around wires and cables and base polymers for flame retardant compositions. BACKGROUND OF THE INVENTION Elastomeric chlorosulfonated ethylene polymers are commercially attractive because they possess a number of desirable properties. Desirable characteristics include:
(a) Chemical solvent resistance, (b) Ozone resistance, (c) Abrasion resistance, (d)
(e) Excellent service temperature, that is, flexibility over a temperature range of about -20°C to about 120°C. Accordingly, cured chlorosulfonated ethylene polymers and compositions based on the polymers having the above-mentioned properties can be used in films such as extrusion coatings around wires and cables or as base polymers in flame retardant compositions. It has applications in a variety of fields including material manufacturing. Traditionally, the production of chlorosulfonated ethylene polymers has been carried out by a solution method in which the polymer is reacted with a chlorosulfonating agent in a solvent. So-called solution processes require that the solvent be removed from the chlorosulfonated polymer upon completion of the reaction, generally by heating the reaction system to a temperature high enough to evaporate the solvent. However, at the temperatures employed for solvent removal, chlorosulfonated polymers tend to aggregate and become difficult to handle and process. It has also been proposed to chlorosulfonate ethylene polymers by a process that involves reacting the polymer with a gaseous chlorosulfonating agent. This process did not appear to be particularly successful because the ethylene polymer was heterogeneously chlorosulfonated. As pointed out in US Pat. No. 3,347,835, cured products obtained from this type of chlorosulfonated ethylene polymer had poor properties. DETAILED DESCRIPTION OF THE INVENTION The present invention enables the chlorosulfonation of ethylene polymers in a manner that avoids the use of solvents and diluents and their associated disadvantages, as evidenced by their excellent balanced properties. This results in the production of a homogeneously chlorosulfonated, granular, elastomeric ethylene polymer. Additionally, the chlorosulfonated ethylene polymer of the present invention is easy to handle and process due to its granular nature. The results of the present invention, in the absence of diluents and/or solvents, have a density of about 0.87 to about 0.93 gr./cc, preferably a density of about 0.89 to about 0.91 gr./cc, and a density of about 0.1 to about 1 c. c./gr, usually about 0.1 to about 0.5cc/
gr., preferably having a pore volume of about 0.2 to about 0.4 cc/gr., is reacted with a gaseous chlorosulfonating agent to provide a tensile modulus of less than about 2000 psi (141 Kg/cm ² ) and about 10% This is accomplished by producing a particulate elastomerol sulfonated polymer, which is a chlorosulfonated polymer having a crystallinity of: The chlorosulfonated ethylene polymers thus produced are homogeneously chlorosulfonated and "elastomeric" and are comparable to commercially available solution-produced chlorosulfonated ethylene polymers. It has excellent balanced characteristics. Ethylene polymers suitable for the purposes of the present invention having the densities and pore volumes described above are disclosed in U.S. Pat.
4302565 and U.S. Patent Application No. 480296 filed March 29, 1983, ethylene-C ₃ - obtained by reacting ethylene with at least one alpha monoolefin under low pressure. It is a _C3 alpha olefin polymer. Particularly desirable ethylene polymers for purposes of the present invention have densities and pore volumes as described above, and from about 50 to
about 99, preferably about 75 to about 96 mole % ethylene and about 1 to about 50, preferably about 4 to about 25 mole % of at least one _C3 - _C8 alpha monoolefin such as propylene, butene-1, Penten
Includes such as 1,4-methylpentene-1, hexene-1, heptene-1 and octene-1. More preferred ethylene polymers to be chlorosulfonated in accordance with the present invention have a molecular weight of about 200 to about 1500,
Preferably an average particle size of about 300 to about 1000 microns, a bulk density of about 10 to about 30, preferably about 15 to about 24, about 0.1 to about 1, usually about 0.1 to about 0.5, preferably about 0.2 to about Pore volume of 0.4cc/gr., and from about 0.87 to about
0.93, preferably about 0.89 to about 0.91 gr./cc. The treatment time with gaseous chlorosulfonating agent is
having a tensile modulus of less than about 2000 psi (141 kg/cm ² ) and a crystallinity of less than about 10%, preferably from 0 to about 5%, and from about 5 to about 55% by weight, preferably from about 15 to Total chlorine content of about 40% by weight and about 0.1~
The time is sufficient to obtain a chlorosulfonated ethylene polymer having a sulfur content of about 10% by weight, preferably from about 0.5% to about 5% by weight. This treatment is believed to cause the replacement of hydrogen atoms on the main chain of the ethylene polymer by Cl and SO ₂ Cl groups. The actual time of processing generally ranges from about 3 hours to about 10 hours depending on the particular ethylene polymer being chlorosulfonated, the chlorsulfonating agent being used and the temperature and pressure employed. change between. Generally, suitable temperatures range from about 50°C to about 130°C,
Preferably the temperature ranges from about 50°C to about 100°C. The pressure at which the reaction is carried out is from atmospheric pressure to approximately 1000psi (70Kg/
It can be changed by the pressure in cm ² ). Provided, however, that neither the reactants nor the by-products condense under the reaction conditions employed. Typically,
The higher the temperature and pressure, the shorter the reaction time. In carrying out the reaction, the amount of chlorsulfonating agent used, such as sulfuryl chloride or a mixture of sulfur dioxide and chlorine, is from about 10 to about 200% by weight, based on the weight of the ethylene polymer being treated, preferably about 20 to about 100% by weight. In examples using a mixture of SO ₂ and Cl ₂ as reactants or modifiers, the molar ratio of Cl ₂ to SO ₂ is approximately 5:1.
~10:1, preferably about 5:1. If desired, an inert gas such as nitrogen can be used in conjunction with the gaseous modifier as a fluidizing agent, diffusion aid, and heat dissipation. The properties described herein were measured using the test methods described below. Density (gr./cc) ASTM-D-1505-Circular samples were prepared and adjusted to approach equilibrium crystallinity at 100°C for 1 hour. Density measurements were then carried out using a density gradient column. Pore volume (cc/gr.) ASTM-C-699-108 (45) Average particle size (μ) Using a 500gr. sample,
Calculated from sieve analysis data measured according to ASTM-D-1921 Method A. Calculations were based on the weight fraction retained on the screen. Bulk Density (lb/ft ³ , gr/cc) Polymer was poured into a 100 ml graduated tube through a 9.5 mm diameter funnel to 100 ml without shaking the tube. The bulk density is
It was determined based on the weight difference between unfilled and filled pipes. Crystallinity (%) duPont with pressure DSC cell
Measured by differential scanning calorimetry (DSC) using a 990 analyzer. Tensile modulus (psi) 4 inches x 4 inches x
A 0.020 inch (10 cm x 10 cm x 0.5 mm) film was compression molded at a temperature of 130°C to 150°C, and its 1% secant modulus was measured according to ASTM-D-638. Tensile Strength (psi) Films prepared as described for tensile modulus testing were
Tested according to ASTM-D-638. Percent Elongation at Break Films prepared as described for the tensile modulus test
Tested according to ASTM-D-638. EXAMPLES The following examples are set forth to illustrate the invention and are not intended to limit the invention. Unless otherwise indicated, the ethylene polymers used as starting materials in the examples were prepared by the method described in U.S. Patent Application No. 480,296, filed March 29, 1983. Polyethylene polymer in a 2-liter glass-lined stainless steel or Hastelloy (55% Nickel, 17% Molybdenum, 16% Chromium, 6% Iron, and 4% Tungsten) reactor equipped with a thermocouple and a motor-actuated U-shaped Hastelloy stirrer. Chlorosulfonated. A Hastelloy dip tube (2 cm diameter) was used to feed the gaseous modifier into the reactor. Unreacted modifier and HCl were vented into a collection trap containing 25% aqueous NaOH. The gaseous modifier is approximately 15~
Under a pressure of approximately 450 psi (1.0-32 Kg/cm ² ), at a rate of 8-15 gr./hr for Cl ₂ and 2-15 gr./hr for SO ₂
It was supplied at a rate of 3 gr./hr. About 200 to about 1000 gr. of the polymer to be treated was placed in a reactor and heated by an external heater. No catalyst was used in carrying out these examples. After the polymer was added to the reactor and heated to the desired reaction temperature, the polymer was stirred with a stirrer and the gaseous modifier was fed. During the modification process, samples of the modified polymer were removed from the reactor and tested for sulfur and chlorine content and percent crystallinity. At the end of the reaction, the flow of gaseous modifier is stopped and unreacted SO ₂ and/or Cl ₂ and HCl are removed.
The product was allowed to cool within the reactor while purging the reaction vessel with nitrogen to remove by-products. Three particulate low density ethylene-butene-1 copolymers A, B, and C were chlorosulfonated according to the present invention. The polymer had the following properties.

【table】

[Table] Ethylene polymer is heated at a temperature of 60℃ to 100℃ to approx.
Chlorosulfonation by reaction with a gaseous mixture of SO ₂ and Cl ₂ for ˜10 hours produced a chlorosulfonated polymer with the properties listed in Table 1. Polymer A was made according to the method disclosed in US Pat. No. 4,302,565.

TABLE The data in this table shows that the elastomers produced according to the present invention have properties comparable to commercially available chlorosulfonated polymers. To further illustrate the need for an ethylene polymer with the density and pore volume mentioned above, 0.935gm/
A control test was conducted using a particulate ethylene-butene-1 copolymer having a density of cc and a pore volume of about 0.3 cc/gm. This copolymer was chlorosulfonated in the manner described above in Example 1 using a mixture of gaseous sulfur dioxide and chlorine. Chlorsulfonation was carried out at a temperature of about 80°C to 100°C for a period of 8 hours. At the end of the 8 hour period, the chlorosulfonation product was analyzed and its properties determined. Control 2 Chlorine % 20 Sulfur % 0.3 Crystallinity % 37 Tensile Modulus psi 30000 (Kg/cm ² ) (2100) However, it was not an elastomeric product. Control 2 polymer was prepared according to the method disclosed in US Pat. No. 4,302,565. The chlorosulfonated ethylene polymer of the present invention is
US Patent No. 24, 1970
No. 3,542,746 to form cross-linked products.

Claims (1)

[Claims] 1. Density of 0.87 to 0.93 gr./cc and 0.1 to 1 c.c./cc.
A granular ethylene polymer with a pore volume of gr.
A process for the chlorosulfonation of an ethylene polymer, characterized in that it produces an elastomeric particulate chlorosulfonated ethylene polymer having a tensile modulus of elasticity of less than Kg/cm ² ) and a crystallinity of less than 10%. 2. The chlorsulfonation method according to claim 1, wherein the chlorsulfonation agent is gaseous sulfuryl chloride. 3. The chlorosulfonation method according to claim 1, wherein the chlorosulfonation agent is a gaseous mixture of sulfur dioxide and chlorine. 4. The chlorosulfonation method according to claim 1, wherein the ethylene polymer is a granular ethylene- _C3 to _C8 alpha olefin polymer having a pore volume of 0.1 to 0.5 cc/gr. 5. The chlorosulfonation process according to claim 4, wherein the ethylene polymer has a density of 0.89 to 0.91 gr./cc and a pore volume of 0.2 to 0.4 cc/gr. 6. The chlorsulfonation method according to claim 4, wherein the chlorsulfonation agent is gaseous sulfuryl chloride. 7. The chlorosulfonation method according to claim 4, wherein the chlorosulfonation agent is a gaseous mixture of sulfur dioxide and chlorine. 8 Ethylene polymer is ethylene and butene-1
The chlorosulfonation method according to claim 4, wherein the chlorosulfonation method is a polymer of 9. The chlorosulfonation method according to claim 4, which is carried out at a temperature of 50°C to 130°C. 10. The chlorosulfonation process according to claim 4, wherein the ethylene polymer has an average particle size of 200 to 1500 microns and a bulk density of 10 to 30.