JP2604772B2 - Chlorinated ethylene-propylene copolymer composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chlorinated ethylene-propylene copolymer composition having excellent mechanical properties. More specifically,
The present invention relates to a chlorinated ethylene-propylene copolymer composition having not only excellent wear resistance, but also excellent flexibility and compression set, and excellent heat resistance.

[Conventional technology]

Chlorinated polyethylene, especially amorphous chlorinated polyethylene rubber, has a chemically saturated structure and is a crosslinked product (vulcanized product) based on a chlorine-containing polymer substance.
Has good physical properties such as weather resistance, flame retardancy, chemical resistance, electrical properties and heat resistance, so it is molded into a wide range of products such as wire coating, electrical parts, hoses, building materials, automobile parts, packing, sheets, etc. Is used in various industrial fields.

However, unlike the general-purpose rubber (for example, a rubber containing butadiene as a main component), the chlorinated polyethylene has a chemically saturated structure as described above, so that it can be vulcanized using sulfur or a sulfur donor as a vulcanizing agent. Have difficulty. Therefore, a method of crosslinking using an organic peroxide as a crosslinking agent is generally used. However, when a hose, a sheet, a tube, or the like is extruded and then crosslinked using a vulcanizing can generally used in the rubber industry, it is difficult to properly crosslink the resulting crosslinked product. Therefore, the crosslinked product obtained is inferior in tensile strength, heat resistance and the like.

Therefore, vulcanization using sulfur or a sulfur donor has been proposed (for example, JP-A-55-71742).
Publication specification). Some of the present inventors have found that vulcanization can be achieved by blending a sulfur thiourea compound, a metal salt of dithiocarbamate, and magnesium oxide and / or lead oxide as an acid acceptor with sulfur and / or a sulfur donor. A vulcanizable chlorinated polyethylene-based composition which is possible and has excellent various mechanical properties (for example, tensile strength) has been proposed (JP-A-61-209244).

However, this composition has the disadvantage that the vulcanizability is not always satisfactory and therefore the flexibility and compression set are not sufficient and the heat resistance is also poor.

In addition, the problems are discussed in detail for each of the commonly used thermoplastic elastomers.

Styrene-butadiene copolymer rubber (SBR) and acrylonitrile-butadiene copolymer rubber (NBR) have excellent oil resistance, cold resistance and flex resistance,
Since it has a double bond in structure, weather resistance, ozone resistance and heat aging resistance are inferior in long-term retention even when a relatively large amount of an antioxidant, an antioxidant or the like is added. Also, ethylene-propylene-diene terpolymer rubber (EPDM) has excellent cold resistance, flex resistance, ozone resistance and heat aging resistance. However, it does not have excellent properties in oil resistance. Further, chloroprene rubber (CR) exhibits excellent properties in oil resistance, cold resistance and flex resistance. However, since it has a double bond like SBR and NBR, the weather resistance and ozone resistance in a short time can be improved by adding a relatively large amount of an antioxidant. However, these properties are degraded with prolonged use. Further, under severe temperature conditions of 120 ° C. or more, heat aging resistance is low. Furthermore, for chlorosulfonated polyethylene, oil resistance, cold resistance,
Flex resistance, ozone resistance and weather resistance have excellent properties.

In addition, it has excellent properties in heat aging resistance up to 120 ° C. However, when subjected to severe conditions of 120 ° C. or more, the heat aging resistance decreases.

[Problems to be Solved by the Invention] From the above, the present invention does not have these disadvantages (problems), that is, not only good heat resistance, oil resistance and weather resistance, but also tensile strength and wear resistance Another object of the present invention is to obtain a composition having excellent properties such as modulus and modulus, and to obtain a composition in which the disadvantages of the thermoplastic elastomer generally used as described above are improved.

[Means and actions for solving the problem]

According to the present invention, these problems are as follows: (A) The propylene content is 15 to 40% by weight, and the melt flow index (measured under the condition of 14 according to JIS K7210, hereinafter referred to as "MFR") Is 0.01 to 5.0 g / 10 min, the melting peak measured by a differential scanning calorimeter is 80 ° C. or more, the crystallinity measured by X-ray is 3% or more,
Moreover, is it a weight average molecular weight, which is an index of the molecular weight distribution measured by gel permeation chromatography?
▼) / The chlorine content obtained by chlorinating an ethylene-propylene copolymer having a number average molecular weight (▲ ▼) of 4 or more is 20 to 45% by weight, and the Mooney viscosity (ML _{1 + 4} (100 ° C.) is 10 to 150 parts by weight, and (B) a chlorinated ethylene-propylene type copolymer composition comprising 10 to 150 parts by weight of carbon black. can do. Hereinafter, the present invention will be described specifically.

(A) Chlorinated ethylene-propylene copolymer In producing the chlorinated ethylene-propylene copolymer used in the present invention, ethylene-
The propylene content of the propylene-based copolymer is 15 to 40% by weight, preferably 18 to 40% by weight, and particularly preferably 20 to 38% by weight. When chlorination is performed using an ethylene-propylene copolymer having a propylene content of 15% by weight, the resulting chlorinated ethylene-propylene copolymer has poor rubber-like elasticity, and is rather plastic-like in products. And does not exhibit the rubbery properties of the resulting composition. On the other hand, when chlorination is performed using an ethylene-propylene-based copolymer exceeding 40% by weight, the particles of the chlorinated ethylene-propylene-based copolymer obtained during chlorination increase, and the particles are aggregated in the reaction system. This is not preferred.

The ethylene-propylene copolymer has an MFR of 0.0
1 to 5.0 g / 10 min, preferably 0.02 to 5.0 g / 10 min, and particularly preferably 0.05 to 5.0 g / 10 min. If chlorination is performed using an ethylene-propylene copolymer having an MFR of less than 0.01 g / 10 minutes, the resulting chlorinated ethylene-propylene copolymer has poor processability. On the other hand, when chlorination is performed using an ethylene-propylene copolymer exceeding 5.0 g / 10 minutes, the reaction efficiency during the production of the chlorinated ethylene-propylene copolymer is poor, and the chlorinated product is strongly aggregated. .

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the ethylene-propylene copolymer is usually from 10 to 180, preferably from 10 to 170, and particularly preferably from 10 to 150. If the propylene-based copolymer is chlorinated, the chlorinated product is strongly agglomerated during the chlorination. On the other hand, when an ethylene-propylene copolymer exceeding 180 is used, the mechanical properties of the obtained chlorinated product are excellent, but the rubber-like elasticity is poor and it is rather plastic-like.

The ethylene-propylene-based copolymer is usually used as a differential scanning calorimeter (DSC).
The melting peak measured in C) is 80 ° C. or more, and the crystallinity measured by X-ray is 5% or more, preferably 80 to 125 ° C., particularly preferably 85 to 125 ° C. If the melting peak is lower than 80 ° C., the chlorinated ethylene-propylene copolymer becomes bulky when producing the chlorinated ethylene-propylene copolymer, which is not preferable because a uniform chlorinated product cannot be obtained.

The ethylene-propylene-based copolymer has a crystallinity of 3% or more as measured by X-ray, preferably 3 to 50%, and more preferably 3 to 45%. This crystallinity is 3
When chlorination is performed using less than 5% of an ethylene-propylene-based copolymer, the chlorination takes place at the chlorination stage, and a uniform chlorinated product cannot be obtained.

Further, the ethylene-propylene-based copolymer has a weight-average molecular weight (▲ ▼) / index of a molecular weight distribution measured by gel permeation chromatography (GPC).
The number average molecular weight (▲) is 4 or more, preferably 4 to 8. It is not preferable to use an ethylene-propylene-based copolymer having ▼ / ▼ of less than 4, because the resulting chlorinated product has poor processability.

In order to produce the chlorinated ethylene-propylene copolymer of the present invention, the ethylene-propylene copolymer is suspended in an aqueous medium. In order to maintain this aqueous suspension, it is preferable to add a small amount of an emulsifier and a suspending agent. At this time, if necessary, a radical generator such as benzoyl peroxide, azobisisobutyronitrile and hydrogen peroxide, a defoaming agent such as light silicone oil, and other additives may be added.

In producing the chlorinated ethylene-propylene copolymer of the present invention, it is desirable to chlorinate the above aqueous suspension by the following three methods.

The first method uses the ethylene-
At least 25 ° C lower than the melting point of the propylene-based copolymer, but at a temperature higher than 50 ° C, the total chlorination amount
20 to 60% is chlorinated, and in the second stage, the temperature is 10 ° C. or more higher than the chlorination temperature in the first stage, but 5 to 15 ° C. higher than the melting point of the ethylene-propylene copolymer.
This is a method of performing the remaining chlorination at a low temperature.

In addition, the second method is at least 25% lower than the melting point of the ethylene-propylene-based copolymer used in the first step.
Although the temperature is lower than 20 ° C., at a temperature higher than 50 ° C., 20 to 60% of the total chlorinated amount is chlorinated, and in the second stage, the temperature is raised to a temperature 1 to 7 ° C. higher than the melting point of the ethylene-propylene copolymer. At a temperature of 2 to 25 ° C. lower than the melting point of the ethylene-propylene copolymer in the third step, in a third step. is there.

Further, the third method is at least lower than the melting point of the ethylene-propylene copolymer used in the first step.
Although the temperature is 25 ° C. lower, but chlorinates 20 to 60% of the total chlorination amount at a temperature higher than 50 ° C., the second stage is a temperature 10 ° C. or higher than the chlorination temperature in the first stage, At least 30% of the remaining amount of chlorination at a temperature 5 to 15 ° C. lower than the melting point of the ethylene-propylene copolymer, 60 to 90% of the total chlorination by this stage;
Then, in the third step, the chlorination is carried out at a temperature lower than the melting point of the ethylene-propylene copolymer but lower than the melting point by 2 ° C. or less.

The chlorine content of the chlorinated ethylene-propylene copolymer used in the present invention thus obtained is 20.
-45% by weight (preferably 20-42% by weight, suitably 25%
~ 42% by weight). If the chlorine content of the chlorinated ethylene-propylene copolymer is less than 20% by weight, there is a problem in recovering and purifying the obtained chlorinated ethylene-propylene copolymer. Moreover, the flame resistance is poor. On the other hand, when the content exceeds 45% by weight, a chlorinated ethylene-propylene-based copolymer produced is not preferred because the thermal stability and heat resistance are significantly reduced.

The Mooney viscosity of a large rotor at a temperature of 100 ° C. is 10 to 150 points, preferably 10 to 120 points, and more preferably 15 to 100 points.

Furthermore, the melt flow index (JIS K-7210
According to the conditions, measured under the condition 7, hereinafter referred to as "FR")
Generally, it is 1 to 100 g / 10 minutes, preferably 3 to 50 g / 10 minutes, and particularly preferably 5 to 30 g / 10 minutes.

(B) Carbon Black The carbon black used in the present invention generally has a non-surface area of a low-temperature nitrogen adsorption method.
²⁰ to 1800 m ² / g as measured by the BET method and a pore volume of 1.5 to 4.0 cc / g as measured by the mercury intrusion method in the range of a pore radius of 30 to 7500 ° (3 to 750 nm), and particularly a specific surface area. Is 600-1
Those with 200 m ² / g are effective.

As the carbon black, channel black,
Thermal black, acetylene black and carbon black produced by the furnace black method. About these carbon blacks, "Carbon Black Handbook" edited by the Carbon Black Association (Book Publishing Company, published in 1972), "Handbook, Rubber / Plastic Compounding Chemicals" edited by Rubber Digest (Rubber Digest, published in 1974) , Said "Synthetic Rubber Handbook"
Their production methods and physical properties are well known. Of these carbon blacks, conductive carbon black racks and acetylene black (generally having a specific surface area of 600 to 1200 m ² / g) obtained by the acetylene method are not suitable because they have high conductivity and high modulus. In addition, channel black obtained by the channel method (generally, specific surface area of 50
(-1200 m ² / g) is used for special purposes, but is not suitable as carbon black for use in the present invention because of its acidic pH. On the other hand, thermal black and furnace black obtained by the thermal method and the furnace method have reinforcing properties, flexibility, abrasion resistance, heat resistance, oil resistance and alkaline properties (as pH) with respect to chlorinated polyethylene. Therefore, it is preferable because high characteristics can be imparted with a relatively small blending amount.

(C) Composition Ratio The composition ratio of carbon black to 100 parts by weight of the chlorinated ethylene-propylene copolymer is from 10 to 150 parts by weight, preferably from 10 to 120 parts by weight, particularly preferably from 10 to 100 parts by weight.
Parts by weight are preferred. The composition ratio of carbon black to 100 parts by weight of the chlorinated ethylene-propylene copolymer is 1
If less than 0 parts by weight, the effect of blending carbon black is poor, that is, the tensile strength of the resulting composition, heat resistance,
The wear resistance, modulus, etc. are not sufficient. on the other hand,
If the amount is more than 150 parts by weight, the flexibility of the composition is reduced.

(D) Mixing method, vulcanization method, molding method, etc. The composition (mixture) of the present invention can be obtained by uniformly blending the above substances, but further, fillers generally used in the rubber industry, Sulfur, sulfur donor, vulcanization accelerator, vulcanization accelerator, organic peroxide,
Crosslinking aids, plasticizers, additives such as oxygen, ozone, heat and light (ultraviolet) stabilizers, lubricants and colorants, and dehydrochlorination inhibitors may be added according to the intended use of the composition. .

When the composition of the present invention is manufactured, the compounding (mixing) method may be compounded using a mixer generally used in the art, such as an open roll, a drive render, a Banbury mixer, and a kneader. Among these mixing methods, in order to obtain a more uniform composition, two or more of these mixing methods may be applied (for example, after mixing by a drive render in advance, the mixture is mixed using an oven roll). how to). If the mixing method is performed at a relatively high temperature during melt kneading, a part or all of the chlorinated ethylene-propylene copolymer used may be crosslinked. For this reason, it is usually necessary to carry out at 70 ° C. or lower.

The composition thus obtained is formed into a desired shape using an extrusion molding machine, an injection molding machine, a compression molding machine, a transfer molding machine or the like generally used in the general rubber industry.

In the case of vulcanization or cross-linking, the vulcanization or cross-linking is usually carried out during molding to a temperature range of 100 to 200 ° C., or by a steam can, an air bath or the like. The vulcanization or crosslinking time depends on the vulcanization or crosslinking temperature, but is generally between 0.5 and 120 minutes.

[Examples and Comparative Examples]

Hereinafter, the present invention will be described in more detail with reference to examples.

In Examples and Comparative Examples, the hardness test was JIS.
Using a hardness tester (Shore A), test specimens are JIS K6301
JIS No. 3 dumbbells were manufactured according to the method described above, and three of these dumbbells were overlapped and measured. The tensile strength (hereinafter referred to as “T _B ”) and elongation (hereinafter referred to as “E _B ”) are JIS
It was measured using a Shopper type tester according to K6301.
Furthermore, the heat resistance test was left at a temperature of 130 ° C. for 72 hours,
The residual ratio of tensile strength and residual ratio of elongation (elongation)
Measured according to 1. In the abrasion resistance test, the amount of abrasion (cc) was measured using an AKRON-type abrasion tester under the conditions of a load of 3 kg and a rotation speed of 1,000 times.

The chlorinated ethylene-propylene copolymer used in Examples and Comparative Examples, carbon black, an acid acceptor, a cross-linking agent, a vulcanizing agent, a cross-linking aid, a vulcanization accelerator and a plasticizer, respectively. Physical properties are shown below.

[(A) Chlorinated ethylene-propylene copolymer]

As a chlorinated ethylene-propylene-based copolymer, an ethylene-propylene-based copolymer having a propylene content of 22% by weight in an aqueous suspension and having a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 115 [ MFR 1.0 g / 10 min, melting point 120 ° C, below `` E
PR (1) "] 10 kg, 50-90 with stirring
In the temperature range of ° C., the copolymer was chlorinated until the chlorine content of the copolymer reached 18.2% by weight (first stage chlorination). Next, the temperature of the reaction system was raised to 121 to 125 ° C., and introduction of chlorine was stopped in this temperature range, and annealing was performed for 30 minutes (second stage annealing). Then, cool the reaction system,
The chlorine content is 35.4% by weight in the temperature range of 95 to 118 ° C.
Chlorinated (third stage chlorination), and the resulting Mooney viscosity (ML _{1 + 4} , 100 ° C.) is 42.0, a chlorinated ethylene-propylene copolymer [MFR 10.0 g / 10 min.
(A) ") and 10 kg of the EPR (1) were charged in the same manner as above, and chlorinated with stirring at a temperature in the range of 50 to 90 DEG C. until the chlorine content of the copolymer reached 18.2% by weight. (First stage chlorination). The reaction was then heated to 105-115 ° C. and chlorinated in this temperature range until the chlorine content was 27.1% by weight (second stage chlorination). Then 11
Chlorination in the temperature range of 8 to 120 ° C until the chlorine content becomes 35.2% by weight (third stage chlorination), Mooney viscosity (ML _{1 + 4} 1
A chlorinated ethylene-propylene-based copolymer (FR 11.0 g / 10 minutes, hereinafter referred to as "CIEPR (B)") having a C.I.

[(B) carbon black]

Further, as the carbon black, carbon black manufactured by the furnace method (manufactured by Showa Cabot Co., Ltd., trade name: Show Black FEF, average particle diameter 51 mm, specific surface area 41 m ² / g, FEF, hereinafter referred to as “CB-1”) ) And carbon black produced by the same method (Asahi Carbon Co., Ltd., trade name: Asahi Thermal, average particle diameter 118 microns, specific surface area 19 m ² / g, S
RF, hereinafter referred to as “CB-2”).

[(C) acid acceptor]

Further, as an acid acceptor, tribasic lead sulfate (produced by Koseisha,
Trade name TS, average particle diameter 2.0 μm, density about 7.0 g / cm ³ , hereinafter referred to as “Tribase”) and magnesium oxide (Kyowa Chemical Co., trade name Kyowa Mag 150, 100 mesh pass,
The specific surface area was 150 m ² / g, hereinafter referred to as “MgO”).

[(D) Crosslinking agent, vulcanizing agent]

Further, n-butyl-bis (tertiary-butylperoxy) valerate (hereinafter referred to as "V") was used as a crosslinking agent, and trithiocyanuric acid (hereinafter referred to as "triazine") was used as a vulcanizing agent.

[(E) Crosslinking aid, vulcanization accelerator]

Further, triallyl isocyanurate (hereinafter referred to as "TAIC") is used as a crosslinking aid, and 2-vulcanization accelerator is used as a vulcanization accelerator.
Mercaptobenzothiazolehexylamine salt (hereinafter referred to as "MDCA") and sodium salt of pentamethylene dithiocarbamate (hereinafter referred to as "PMTC") were used.

[(F) plasticizer]

Trioctyl trimellitate (hereinafter referred to as "TOTM") was used as a plasticizer.

Examples 1 to 10 and Comparative Examples 1 to 4 Chlorinated ethylene-propylene copolymers (hereinafter referred to as “CI-EP
R "), carbon black (hereinafter" CB "), an acid acceptor and a vulcanization accelerator, and Examples 1-4.
In Examples 8 and 10, and in Comparative Example 1, 4 parts by weight of V and 3
2 parts by weight of TAIC in Examples 5 to 9 and Comparative Examples 2 to 4.
0 parts by weight of triazine (0.2 parts by weight in Example 8) and 30 parts by weight of TOTM in Examples 1 to 10 and Comparative Examples 1 and 2 are kneaded with an oven roll at room temperature (about 20 ° C.) for 20 minutes. Each was formed into a sheet. The temperature of each obtained sheet is 165 ° C using a compression molding machine.
And vulcanized or cross-linked while vulcanizing or cross-linking under the conditions of 200 kg / cm ² for 30 minutes. Each of the obtained vulcanized products and crosslinked products was tested or measured for tensile strength, elongation, hardness, heat resistance and abrasion resistance. Table 2 shows the results.

In Comparative Example 4, a good sample could not be prepared because dehydrochlorination occurred.

From the results of the above Examples and Comparative Examples, the chlorinated ethylene-propylene copolymer composition of the present invention is excellent not only in tensile strength (T _B ) and abrasion resistance but also in heat resistance. Is obvious.

〔The invention's effect〕

The chlorinated ethylene-propylene copolymer composition of the present invention exhibits the following effects (features).

(1) Good mechanical strength (for example, tensile strength).

(2) The dimensional accuracy of the molded product is excellent.

(3) Good chemical resistance and weather resistance with respect to rubber having a double bond.

(4) Good compression set.

(5) The vulcanizate or crosslinked product has excellent vulcanizability or crosslinkability.

(6) Good oil resistance.

(7) Excellent permanent elongation.

(8) Good heat resistance.

The chlorinated ethylene-propylene copolymer composition of the present invention can be used in various fields in order to exhibit the above effects. Representative applications are shown below.

(1) Various rubber parts for automobiles (for example, packing and hose) (2) Electric wire coating (3) Parts of electrical equipment and electronic equipment (4) Various packings and sheets (5) Hose (6) Various building materials Parts (7) Roofing, bond liner

Claims (1)

(57) [Claims] (1) a content of (A) propylene of 15 to 40% by weight;
And the melt flow index is 0.01 to 5.0 g / 1
0 minutes and the melting peak measured by a differential scanning calorimeter is 80
Ethylene-propylene having a degree of crystallinity of 3% or more as measured by X-ray and a weight average molecular weight / number average molecular weight of 4 or more as an index of molecular weight distribution measured by gel permeation chromatography. The chlorine content obtained by chlorinating the copolymer is 20
~ 45% by weight and Mooney viscosity (ML _{1 + 4} , 100 ℃)
A chlorinated ethylene-propylene-based copolymer composition comprising 100 parts by weight of a chlorinated ethylene-propylene-based copolymer having a molecular weight of 10 to 150 and (B) 10 to 150 parts by weight of carbon black.