JPS62207310A - Ethylene/alpha-olefin copolymer rubber - Google Patents

Abstract

PURPOSE:To obtain an ethylene/alpha-olefin coplymer rubber improved in heat resistance, low-temperature resistance, processability and properties of a vulcanizate, by specifying the composition, properties, etc., of the copolymer. CONSTITUTION:This ethylene/alpha-olefin copolymer rubber has the following characteristics. Namely, (A) it comprises ethylene and a 3-8C alpha-olefin, (B) the ethylene content is 60-30wt% (C) the intrinsic viscosity as measured in xylene at 70 deg.C is 1.6-4.0dl/g, (D) its Q value (weight-average MW/number- average MW)>=4 and (E) the elongation at break EB as measured at 23 deg.C is 90% or above and the green strength index G is in the range of G>=0.8 and GM>=1.3G100. Examples of the alpha-olefins which are particularly preferable include propylene and 1-butene.

Description

[Detailed description of the invention] <Industrial utility field> The present invention provides ethylene, lene/α-olefin copolymer rubber,
Furthermore, the present invention relates to an ethylene/α-olefin copolymer rubber that has a wide molecular weight distribution, unique raw rubber green strength, and good processability.

Ethylene/α-olefin copolymer rubber has excellent heat resistance, cold resistance, and weather resistance, and is used in automobile parts, industrial products, electrical parts, etc.1 For example, socket covers, heat-resistant hoses, electric wires, and capacitor caps.

Heat-resistant belts, vibration-proof rubber, etc. can be used.

<Conventional technology> Generally, ethylene/propylene copolymer rubber.

Ethylene/l-butene combined ffi comb, Ethi L/
1-propylene-polyene ternary copolymer rubber: ethylene-1-butene-polyene ternary copolymer rubber.

Rubber compositions made of ethylene/α-olefin or ethylene/α-olefin/polyene copolymer rubber have excellent weather resistance, heat resistance, ozone resistance, etc., and are useful as building materials,
It is known to be used for electric wire materials, automobile parts, etc.

Among such uses, it is well known that ethylene/α-olefin copolymer rubber, which does not contain polyene, is preferable for uses where heat resistance is particularly required. Also for applications that require cold resistance.

The ratio of ethylene to ethylene and α-olefin is 6
A copolymer rubber with an ethylene content of 0 wt% or less is preferable, and for applications requiring heat resistance and cold resistance, an ethylene/α-olefin copolymer rubber with an ethylene content of 60 wt% or less in the copolymer is preferable. well known.

Further, as properties required of the ethylene/α-olefin copolymer rubber used in such applications, it is desired that the rubber has excellent processability and, at the same time, excellent vulcanization properties.

However, with the technology shown in the conventional literature, ethylene, which has good processability and vulcanizable properties, and has excellent heat resistance and cold resistance,
No means for obtaining α-olefin copolymer rubber was known.

<Problems to be Solved by the Invention> An object of the present invention is to solve these problems and provide a material with excellent heat resistance and cold resistance, as well as excellent processability and vulcanizable properties. An object of the present invention is to provide an ethylene/α-olefin copolymer rubber.

Means to solve problems〉 The present inventors found that processability and vulcanizable properties were good.

It also has excellent heat and cold resistance. This is the result of intensive study on two ethylene/α-olefin copolymer rubbers.

We have discovered an ethylene/α-olefin monolithic rubber that achieves this objective. This ethylene/α-olefin copolymer rubber is characterized by an ethylene content of 60 to 30 wt%.
The Q value of the two molecular weight distribution is 4 or more, and the ethylene content of the high molecular weight portion is higher than the average ethylene content of the copolymer, and as a result, the green strength of the raw rubber is extremely high.

The ethylene/α-olefin copolymer of the present invention is unique from the viewpoint of the conventional ethylene/α-olefin copolymer i1 (in the case of a composite comb, the gun strength of raw rubber decreases as the ethylene content decreases). It can be seen that it is.

In other words, one aspect of the present invention is.

(g) Consisting of ethylene and an α-olefin having 3 to 8 carbon atoms.

B) Ethylene content is 60 to 30 wt%.

Intrinsic viscosity measured at 70°C in 0 xylene is 1.6 to 4.0 dε/y.

DQ value (weight average molecular weight/number average molecular weight) is 4 or more.

The elongation at break of the copolymer rubber measured at 023°C is 90
0% or more, and the green strength index G is G≧0.8,
and G2≧1.3G. . .

It is characterized by This invention relates to an ethylene/α-olefin copolymer rubber that has excellent heat resistance, cold resistance, and good processability.

In addition, the ethylene/α-olefin copolymer rubber according to the present invention has an ethylene content of the high molecular weight component of E++wt%,
When the average ethylene content is expressed as EAwt%.

10≦EB−E≦30 It is preferable to have this relationship.

The α-olefin having 3 to 8 carbon atoms, which is a component of the copolymer rubber of the present invention, includes propylene, 1-)tene, 1-pentene, and 1-hexene.

Examples include 4-methyl-1-pentene, I-octene, and mixtures thereof; propylene, I-octene, etc.
Butene is particularly preferred.

6) Ethylene content in 111 rubber is 60 to 30
selected within the range of wt%. Ethylene content is 60wt%
If the temperature is higher than that, a decrease in cold resistance is observed, which is not preferable.

Further, even if the ethylene content is 30 wt% or less, a decrease in cold resistance is observed.

The ratio of ethylene to α-olefin varies depending on the type of α-olefin, but when the α-olefin is propylene, the ethylene content is in the range of 60 to 30 vt%, preferably 60 to 40 wt%. .

The ethylene content can be determined by measuring C-NMR spectrum or absorbance using an infrared spectrophotometer.

The zero intrinsic viscosity of the copolymer rubber of the present invention is 70 in xylene.
1.6 to 4, as measured by the 3-point method at °C
rt7! /q range is preferred. 1.6 dll f
Below, the vulcanization properties are poor, and at 4, Qdl/f, the kneading process is difficult.

Extrusion processing becomes difficult, which is not preferable.

The molecular weight distribution of the copolymer rubber is an important factor that serves as an indicator of processability.1 In the present invention, G) IQ value (weight average molecular weight/number average molecular weight) is 4 or more, preferably 6 or more. is preferred. If the Q value is less than 4, good workability cannot be obtained.

The Q value was measured as follows in accordance with "Gelpermeen Chromatography" written by Takeuchi and published by Maruzen.

1:': ”:”:: 'l\73Made by Ers 15
0cm column: Showa Denko 5hodex 80MA
Sample amount: 300 μt (polymer concentration 0.2 wt%
) Flow rate: 1 ml/min Temperature: 135°C Solvent: Nitrichlorobenzene The calibration curve was prepared by a conventional method using standard borinutylene manufactured by Toyo Soda ■. Further, data processing was performed using a data processor CP-8 model ■ manufactured by Toyo Soda ■.

The green strength and elongation at break of the copolymer rubber of the present invention are also important indicators of processability and vulcanization properties, and (E) the elongation at break EB measured at 123° C. is 900% or more.

Green intensity index G is G≧0.8 and GM≧1.3
G+aa, more preferably G≧0.9. GM≧1.5
It is necessary to be within the range of G+an.

Here, the green strength index G is expressed as G=G, yen/G100, and Gmo is the stress at 900% elongation r G+on
is the stress at 100% elongation. Moreover, GM indicates breaking strength. The tensile test was conducted using a T-type strograph manufactured by Toyo Seiki under the following Q conditions.

Test piece: JISa dumbbell thickness 21 tensile speed: 50
0 tone/min measurement temperature: 23℃ If the green strength index G is G<0.8, the breaking strength GM is GII (1,3G+oo), and the elongation at break EB is less than 900%, the workability, especially the roll workability, is poor. It is.

Further, the copolymer rubber of the present invention has a relationship between the ethylene content EB of the high molecular weight component and the average ethylene content EA.

Preferably, the following formula is satisfied.

That is, 10≦E knee EA≦30. More preferably, the range is 15≦EB-EA≦30.

If EB-EA<10, the green strength will be low and processability will be poor; if EB-EA>30, the ethylene content in the high molecular weight portion will be high and the cold resistance will be reduced.

Here (this high molecular weight component, the ethylene content of the high molecular weight component E
II+average ethylene content EB is defined as follows.

(2) The copolymer rubber is separated into 16 to 21 fractions by column fractionation. --Ichigin Imadanwa 4
Measure the ethylene content and intrinsic viscosity of each of the nine fractionated 1 liters. The separation conditions are as follows.

(i) Copolymer rubber 302 is coated on 265Of sea sand having a mesh size of 60 to 80.

(Li) Elute at 80°C using a mixed solvent of toluene/isopropyl alcohol for elution mixing.

The first flux was eluted by changing the composition of toluene/isopropyl alcohol into the same bottle into which the elution solution was taken at 8 cc/min for 4 hours. The composition of toluene/isopropyl alcohol is 50/50 (vo1%
), increase the toluene ratio sequentially to 51/49.52/48.53/47, and if necessary, elute the final crackin with 100% toluene.

(2) After concentrating the eluate, it was precipitated in methanol.

The precipitate is dried under vacuum and its weight is measured.

(2) Create a cumulative curve in order of molecular weight of the fractionated products, and divide into two, 20 wt% on the high molecular weight side and 80 wt% on the remaining weight side.

Measure the ethylene content of each. The component on the high molecular weight side is H2, and its ethylene content is 'EBwt%, and the average ethylene content is E Awt%. As a result, EB, EA
is required.

Next, an example of the method for producing copolymer rubber according to the present invention will be described.

A so-called Ziegler-Natsuta catalyst is used as a catalyst for producing the copolymer of the present invention, which requires a combination of an organoaluminum compound and a trivalent to pentavalent vanadium compound soluble in a hydrocarbon solvent.

Examples of the aluminum compounds include alkyl aluminum sesquichloride, triple aluminum sesquichloride, and dialkyl aluminum monochloride.

Alternatively, a mixture thereof is preferable, and the vanadium compound includes vanadium trichloride, vanadium tetrachloride, or V○(OR)nXi-n (o<n≦3,
Preferably, R is a vanadium compound represented by a linear bibranched or cyclic hydrocarbon having 1 to 1 carbon atoms.

At this time, the ratio of the organic aluminum compound to the tohanadium compound is preferably in the range of 6.0 to 2.0. If it is less than 2, a large amount of gel will be formed or the activity will be significantly reduced, and if it is more than 6, the Q value will be small and the copolymer targeted by the present application cannot be obtained. In manufacturing the combination,
The copolymer may be produced in such a way that a high molecular weight component containing an ethylene content higher than the average ethylene content of the copolymer is partially produced. This is more than 2 tanks.

Alternatively, in a two or more stage polymerization method, this can be achieved by controlling the composition and amount of the copolymer produced in the first and second tanks, or the first and second stages, etc. . By this method, ethylene α according to the present invention can be obtained.
- An olefin copolymer rubber is obtained.

The composition of the copolymer rubber can be adjusted by varying the ratio of ethylene to alpha-olefin in one reactor. Also, what is the molecular weight of the copolymer rubber?

Concentration of hydrogen used for molecular weight adjustment 1 heavy metal degree,
and the concentration of ethylene and α-olefin in the reactor. The polymerization temperature is preferably in the range of 35°C to 70°C, more preferably 40°C to 70°C.

If the ethylene copolymer of the present invention is used, in addition to the characteristics of good processability and excellent cold resistance and heat resistance,
By vulcanization with peroxide.

A high-strength vulcanizate is obtained. This vulcanizate is used for automotive parts such as socket covers and hoses, electric wires, capacitor caps, heat-resistant belts, and vibration-proof rubber.

<Examples> The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

Example 1゜ In a 10t SUS autoclave equipped with a stirrer.

7 KI of hexane every hour? , ethylene, and propylene were each fed at a rate of 1.65 kg for 33 hours each. Further, hydrogen was fed at a rate of 0.036 mol%. In addition, ethylaluminum sesquichloride and vanadyl trichloride were used as catalyst components at 2.289 and 0.0% per hour, respectively.
．． The polymerization was carried out at 46° C. by feeding at a rate of 57 y.

The polymerization was continued for 4,+o hours after reaching a steady state, and then ethylene and propylene were added at 0.62θ and 1.61θ, respectively.
Ethylaluminum sesquichloride and vanadyl trichloride were added to the ratio of Kf at 0.682 and 0.682 per hour, respectively.
The ratio was changed to 179%, and one polymerization was continued for an additional 4 hours. The copolymer solution was continuously extracted, demonomerized, washed, and then charged into a separate drum.

After polymerization path T, the copolymer solution in 1- was steam stripped to separate the polymer and dried.

Thus, the ethylene content is: EA = 52 wt%, E =
An ethylene/propylene copolymer having an intrinsic viscosity of 70 wt%, an intrinsic viscosity of 2.39 alt, and a Q value of 8.6 was obtained. When the green strength of this copolymer was measured, G = 1.8.
G,=2,6 G+oo, elongation at break was 940%.

In addition, the roll processability of this copolymer was evaluated, but no so-called bagging occurred.

It had good roll workability.

In addition, the physical properties of the vulcanized product were measured.

300% Monoyulas 53 Kqf/cr
l Breaking strength 130 K9 f/c++i Breaking elongation 580% Hardness (JIS-A) 6] Compression set 32% (-20°C x 22 hours) Heat aging test (175°C x 70 hours, with the gear open)
The breaking strength (retention rate) was 75%, the breaking elongation (-) was 92%, and the hardness (change value) was +12.

In addition, the tensile physical properties were based on JIS-6301.

Also, evaluation of roll processability and preparation of vulcanizate ii.

The following method was used. The same applies to the following Examples and Comparative Examples.

■Blending ■Kneading Mixing compound A was mixed in a BR Banbury, 12 bowls x 5 minutes, added all at once, and started at 70°C. Thereafter, formulation B was added at 8-inotylol to obtain a formulation. Roll temperature 50℃
.

■ Roll: 6 inch roll Roll temperature 50℃ Roll gap 2III11 The wrapping was evaluated in terms of gender.

■ Vulcanization conditions: Futusu vulcanization was performed at 160°C12O.

Example 2゜ Example 1. Polymerization and post-treatment operations were performed in the same manner as above.

However, the polymerization temperature was 40°C. Thus, the ethylene content is: EA=50wt%, Eg=70wt%, intrinsic viscosity 2.76del? , a copolymer with a Q value of 6.7 was obtained. The green strength of this copolymer was measured.

G=0.9. GM = 1.8 x G100, elongation at break was 1500% or more. (At this time, GM is 1500
It is represented by the strength at % elongation. ) Also, when the roll processability of this copolymer blend was evaluated, so-called bagging did not occur.

It had good roll workability.

In addition, the physical properties of the vulcanized product were measured.

300% Monzilas 81KIIf/i Breaking strength 174 hf /c++ [Elongation at break 520% Hardness (JIS-A) 63 Compression set 28% (-20°C x 22 hours) Heat aging test (175°C x 70 hours, gear open) Medium) Breaking strength (retention rate) 71% Breaking elongation (-) 90% Hardness (change value) +11.

Comparative Example 1゜Using the same reactor as in Example 1, 7 to 9 parts of hexane was added every hour.
．． Ethylene, propylene each 0.33Kf, 1.6
It was fed at a rate of 5 odors. Further, hydrogen was fed at a rate of 0.015 mol%. Furthermore, ethylaluminum sesquichloride and vanadyl trichloride were fed as catalyst components at a rate of 2.28 f and 0.57 y per hour, respectively, and polymerization was carried out at 46°C.

After reaching steady state, polymerization was continued for 14 hours.

The copolymer solution was successively fleased, drained, demonomerized, and washed before being charged into the IFFI' drum. After the polymerization was completed, the copolymer solution in the drum was subjected to steam stripping to separate the polymer and dry it.

Thus the ethylene content is: EA = 5 hvt%,
A copolymer having an EB of 60 wt%, an intrinsic viscosity of 2.38 dl/l, and a Q value of 4.6 was obtained. However, when we measured the green strength of this copolymer, we found that G = 0.4
, G-=0.30+o.

(G, 141500% elongation stress adopted) EB>
It was 1500%.

Further, roll processability of this copolymer was evaluated, but so-called bagging occurred and loaf processability was poor.

In addition, the physical properties of the vulcanized product were measured.

300% modulus 70 to 4f/- Breaking strength 128 Kfr 7aa Breaking elongation 510% Hardness (JIS-A) 62 Compression set 30% (-20°C x 22 hours) Heat aging test (175°C x 70 hours, (gear open)
The breaking strength (retention rate) was 78%, the breaking elongation (#) was 90%, and the hardness (change value) was +12.

Comparative example 2゜ Comparative example 1. Polymerization and post-treatment were carried out in the same manner as above.

However, the polymerization temperature was 40° C., and hydrogen was fed at 0.01 mol %. Thus, the ethylene content is *EA=54wt
%.

En = 62wt%, intrinsic viscosity 2.93d7! /r,
A copolymer with a Q value of 3.4 was obtained. When the green strength of this copolymer was measured, the elongation at break was 430%, and the green strength of the copolymer was 430%.
could not be measured. Also GM= 0.35 G+aa
Met.

The roll processability of this copolymer formulation was evaluated, but it resulted in bagging and holes in the sheet.

Roll processability was poor.

Also, what are the physical properties of the vulcanizate?

300% modulus 78Kff/, -,! Breaking strength 168Kqf/crl Breaking elongation 520% Hardness (JIS-A) 65 Compression set 30% (-20℃ x 22 hours) Heat aging test (175℃ x 70 hours, gear open)
The breaking strength (retention rate) was 72%, the breaking elongation (#) was 90%, and the hardness (change value) was +13.

Comparative example 3゜ Comparative example 1. Polymerization and post-treatment were carried out in the same manner as above.

However, the polymerization temperature was 50°C, hydrogen was fed at 0.07 mol%, and ethylene and propylene were each fed at 0.46%/hour.
The feed rate was 9 and 1.41 kg. Furthermore, 5
-ethylidene-2-norbornene at 0.037 Kf/hour
Feed at a rate of Further, as catalysts, ethylaluminum sesquichloride and vanadium oxytrichloride were fed at a rate of 2.52 sr and sr per hour, respectively.

What is the ethylene content of the copolymer thus obtained?

EA-68 wt%, E*=71 wt%, iodine value was 3, intrinsic viscosity was 1.86 at/y, and Q value was 2.7.

The green strength of this copolymer was evaluated.

G=4.4. -GM=8.0G+oo, E-=128
It was 0%.

Further, when the roll processability of the blend of this copolymer was evaluated, the roll processability was found to be good.

However, when we measured the physical properties of the vulcanizate, we found that the low-temperature properties (
Low-temperature compression set) was poor, and heat aging resistance was also poor.

Physical properties of vulcanizate 300% modulus 82Kff, /! Breaking strength: 170 to 9 f/cd Elongation at break: 500% Hardness (JIS-A): 64 Compression set (-20°C x 22 hours) 82% heat aging test (
175'C Compared to other technologies, it has excellent heat resistance and cold resistance, as well as excellent processability and vulcanizable properties. Ethylene/α-olefin copolymer rubber can be provided.

Claims (4)

[Claims] (1) (A) Consisting of ethylene and an α-olefin having 3 to 8 carbon atoms; (B) ethylene content of 60 to 30 wt%; (C) intrinsic viscosity measured in xylene at 70°C of 1.6 to 4.
．． 0 dl/g, (D) Q value (weight average molecular weight/number average molecular weight) is 4 or more, (E) Elongation at break of the copolymer E_B measured at 23°C is 9
00% or more, the green strength index G is G≧0.8, and G_M≧1.3G_1_0_0,
An ethylene/α-olefin copolymer rubber characterized by: (2) (A) α-olefin is propylene, (B
) The copolymer rubber according to claim 1, having an ethylene content of 60 to 40 wt%. (3) The copolymer rubber according to claim 1, wherein the α-olefin (A) is 1-butene. (4) (E) The green strength index G of the copolymer measured at 23°C is G≧0.9, and G_M≧1.5G_1_0
The copolymer rubber according to claim 1, which is _0.