JP2604774B2 - 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 strength. More specifically,
Chlorinated ethylene-propylene not only has excellent mechanical strength (for example, tensile strength), but also has good flexibility and compression set, and has excellent heat resistance and abrasion resistance. The present invention relates to a copolymer composition.

[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 drawbacks (problems), that is, it has not only good heat resistance, oil resistance and weather resistance, but also excellent properties such as tensile strength, wear resistance and modulus. It is an object of the present invention to obtain a composition, and moreover, to obtain a composition in which the drawbacks of the thermoplastic elastomers 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, the 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} Chlorinated ethylene-propylene copolymer comprising 100 parts by weight of a chlorinated ethylene-propylene copolymer having a temperature of 100 to 100 ° C, and (B) 10 to 150 parts by weight of an inorganic substance having a Si—O bond. Coalescing composition. 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, if the content exceeds 45% by weight, the chlorinated ethylene-propylene 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) an inorganic substance having an SiO bond Further, the content of SiO ₂ inorganic material having a SiO bond used in the present invention is usually at least 10 wt%, preferably at least 30 wt.%, In particular 50 % By weight or more is preferred. The content of H ₂ O is usually 1.0 to 20% by weight, preferably 1.0 to 15% by weight, and more preferably 1.5 to 15% by weight.
Is preferred. Further, the particle size of the inorganic substance is generally 10
nm to 30 μm, preferably 10 nm to 25 μm, and more preferably an inorganic substance having a particle size of 15 nm to 25 μm.

Representative examples of inorganic substances having a Si-O bond include wet-process white carbon, calcium silicate, colloidal silica, some calcium, aluminum, sodium,
Synthetic silicate-based white carbon containing oxides such as iron, ultrafine magnesium silicate, aluminum silicate (clay), talc, nepheline syenite, mica powder, silica powder, diatomaceous earth, silica sand, etc. can give. These inorganic substances having a Si—O bond can be prepared by the methods described in Rubber Digest, Inc., “Handbook of Rubber / Plastic Compounded Chemicals”) Rubber Digest, published in 1974) pp. 221 to 253, and the like. It describes physical properties and trade names, and is well known.

(C) Composition ratio The composition ratio of the inorganic substance having a Si—O bond to 100 parts by weight of the chlorinated ethylene-propylene copolymer is 10%.
To 150 parts by weight, preferably 10 to 120 parts by weight, particularly preferably 10 to 100 parts by weight. If the composition ratio of the inorganic substance having a Si-O bond to 100 parts by weight of the chlorinated ethylene-propylene copolymer is less than 10 parts by weight, the effect of blending the inorganic substance having a Si-O bond is poor, that is, it is obtained. The tensile strength, heat resistance, abrasion resistance, modulus and the like of the composition are not sufficient. On the other hand, if the amount exceeds 150 parts by weight, the flexibility of the composition decreases.

(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 furthermore, dehydrochlorination generally used in the rubber industry. Inhibitor, sulfur, sulfur donor, vulcanization accelerator, vulcanization accelerator, organic peroxide, crosslinking aid, plasticizer, oxygen, ozone, heat and light (ultraviolet) stabilizer, lubricant and colorant Such additives as described above 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 open 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 120 ° C for 72 hours,
The residual ratio of tensile strength and the residual ratio of tensile elongation (elongation) are JIS
It was measured according to K6301. 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 number of rotations of 1,000.

The chlorinated ethylene-propylene copolymer used in Examples and Comparative Examples, an inorganic substance having a Si-O bond, an acid acceptor, a crosslinking agent, a vulcanizing agent, a crosslinking aid, a vulcanization accelerator and a plasticizer The types and physical properties of the agents 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) Inorganic substance having Si-O bond]

Further, as an inorganic substance having a Si—O bond, ultrafine magnesium silicate (density 2.75 g / cm ² , specific surface area 20 m ² / g,
Particle size from 0.32 to 6 microns, SiO ₂ content of 62.5 wt%, MgO
Content 30.6% by weight, Fe ₂ O ₃ content 1.0% by weight, H ₂ O content 4.99% by weight, hereinafter referred to as “MgO · SiO ₂ ”, silica (density 1.95g / cm ³ , specific surface area 19,000cm ² / g, average particle size 16
Millimicron, SiO ₂ content 86.5% by weight, H ₂ O content 13.0
% By weight, hereinafter referred to as “SiO 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, Comparative Examples 1 to 5 Chlorinated ethylene-propylene copolymers (hereinafter referred to as "Cl-EP
R), an inorganic substance having a Si-O bond (hereinafter referred to as "C.
B. "), an acid acceptor and a vulcanization accelerator and 4 parts by weight of V in Examples 1-4, Examples 8 and 10, and Comparative Example 1.
And 3 parts by weight of TAIC, Examples 5-9 and Comparative Examples 2
In Example 5, 2.0 parts by weight of triazine (however, in Example 8,
(0.2 parts by weight), and in Examples 1 to 10 and Comparative Examples 1 and 2, 30 parts by weight of TOTM were kneaded at room temperature (about 20 ° C.) for 20 minutes using an oven roll, and each was formed into a sheet. Each of the obtained sheet-like materials was vulcanized or cross-linked using a compression molding machine at a temperature of 165 ° C. and a pressure of 200 kg / cm ² for 30 minutes to produce a vulcanized product and a cross-linked product. 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.

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 ℃)
(B) a chlorinated ethylene-propylene copolymer composition comprising 10 to 150 parts by weight of an inorganic substance having a Si-O bond.