JPS614745A - Rubber composition - Google Patents

Abstract

PURPOSE:A rubber composition which has excellent processability and mechanical strength, and is low-cost, suitable for automobile hoses, a waterproof sheet, a belt, etc., and prepared by using an ethylene-alpha-olefin-diolefin copolymer rubber having specified molecular characteristics. CONSTITUTION:A rubber composition prepared by incorporating 150-450pts.wt. filler and 60-250pts.wt. softening agent into 100pts.wt. ethylene-alpha-olefin-diolefin copolymer rubber which is made from 3-12C alpha-olefin, and has a weight ratio of ethylene/alpha-olefin of 80-65/20-35, a content of bonded diolefin units in terms of iodine value of 5-25, a Mooney viscosity ML1+8 at 120 deg.C of 60-280, an insoluble matter in cyclohexane at 30 deg.C of 15wt% or less, and a weight-average molecular weight/number-average molecular weight (Q value) of not less than A and not more than B, respectively calculated by formulas I and II, where C is the Mooney viscosity (ML1+8, 180 deg.C) of the copolymer rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a rubber composition with excellent mechanical strength and processability.

"Conventional technology" Ethylene-α-olefin-diolefin copolymer rubber has excellent weather resistance and heat aging resistance, so it is widely used in automotive parts, waterproof sheets, plastic modification, electric wires, etc. It's been a long time. Furthermore, ethylene-α-
Compared to natural rubber, styrene/butadiene rubber, etc., olefin-diolefin copolymer rubber has a relatively slow decline in mechanical strength even when filled with carbon black, softeners, etc., so it has high filling properties. Being superior has also been cited as one of its major characteristics.

However, in recent years, there has been an increasing demand for higher loadings of inexpensive fillers and softeners from the viewpoint of resource and energy conservation. In addition, workability during kneading, grain workability,
The required performance, mainly related to workability, such as the compound being fed into the extruder, the consistency of the compound after kneading, the smoothness of the surface of the compound applied to a roll, and the smoothness of the extruded surface, are the same as before, and of course, However, the requirements for the mechanical strength of vulcanizates are also becoming more stringent.

It has been known that polymers with high molecular weight, high ethylene content, and sharp molecular weight distribution are good as polymers that exhibit less deterioration in physical properties when highly filled.

However, processability, especially the cohesion of the compound after kneading, deteriorates. Furthermore, problems such as increased energy consumption during kneading remain unsolved.

In addition, it has been proposed to widen the molecular weight distribution in order to obtain polymers with good processability, but these do not have sufficient vulcanizable physical properties and have good processability when used in highly filled formulations. Polymers are not proposed.

"Problems to be Solved by the Invention" In order to reduce the cost of vulcanizate products, the present inventors have reduced the amount of relatively expensive ethylene-α-olefin-diolefin copolymer rubber used, and As a result of intensive studies to obtain a copolymer rubber with excellent properties and vulcanizable properties, it was discovered that an ethylene-α-olefin-diolefin copolymer rubber having specific molecular properties could be used, leading to the completion of the present invention. Ta.

That is, the present invention provides an ethylene-α-olefin-diolefin copolymer rubber 1 that satisfies the following conditions (1) to (4).
00 parts by weight: 150 to 450 parts by weight of filler;
and a softener in an amount of 60 to 250 M parts (1) The α-olefin has a carbon number of 3 to 12, and the weight ratio of ethylene/α-olefin is 80 to 65/20.
35. The bonding amount of diolefin units is 5 to 25° in terms of iodine value (2) Copolymer rubber Tsukuni viscosity is ML 1+8.12
60-280 at 0'C.

(3) When the copolymer rubber is dissolved in cyclohexane at 30°C, the amount of insoluble matter (cyclohexane insoluble matter) is 15.
ii or less.

(4) Weight average molecular weight/number average molecular weight (Q
value) is greater than or equal to A value and less than B value calculated by the following formula A=0.042 xC-2,34 B=0.042 xc+0.48 C: Mooney viscosity of copolymer rubber (ML 1+8.120 °C).

The copolymer rubber used in the present invention must satisfy all of the conditions (1) to (4) above. Even if a copolymer rubber lacking these conditions is used, a highly filled vulcanizate with excellent processability and physical properties cannot be obtained.

“Means to solve Ma Zhao” (and “action”) ■
The ethylene content relative to the total amount of ethylene component and α-olefin component in the copolymer rubber is 80 to 65 m<:1%,
Preferably it is 75 to 70% by weight. For example, even if other conditions are met, if the ethylene content exceeds 80% by weight, fluidity deteriorates and wasteful energy is required during kneading.

Further, processing problems such as deterioration of biting into rolls and extruders occur.

Furthermore, if a copolymer rubber having an ethylene content of less than 6 swt% is used, the strength of the vulcanizate will be insufficient.

In addition, if the amount of diolefin unit bonding in the copolymer rubber is expressed by the iodine value, it is 5 to 25. If the iodine value is less than 5, it is not possible to cope with high-speed vulcanization that accompanies energy saving in the dispensing process. If it exceeds this, it will not be possible to satisfy the originally required requirements such as weather resistance, as well as the requirements such as scorch resistance.

■Mooney viscosity of the copolymer rubber used in the present invention is M
L 1+8.1 It is necessary to be 60 to 280 at 20°C, and p is preferably 65 to 240. If the Mooney viscosity is less than 60, the strength of the vulcanizate will be insufficient, and if it exceeds 280, there will be crosstalk.
Difficulties arise in processability during molding. These copolymer rubbers may also be used as oil-extended rubbers containing a softener.

(2) The content of cyclohexane insoluble matter in the copolymer rubber at 30° C. is 15 Jlt% or less, preferably 10% by weight or less.

The cyclohexane insoluble content is mainly composed of crystalline components that are hard to form long chain bonds of ethylene.
If it exceeds 5% by weight, the same processing problems as when the ethylene content is 80 mt% or more arise due to deterioration of fluidity.

■ The purpose of the present invention is to provide a highly filled composition with excellent processability and additive properties.To achieve this, it is necessary to use a specific copolymer rubber as described above.
Furthermore, Mooney viscosity and molecular weight distribution must satisfy the following conditions. That is, the weight average molecular weight/number average molecular weight (Q value) of the copolymer rubber is greater than or equal to value A and less than value B, which is calculated using the following formula.

A=0.042 xC-2,34 B=0.042 xc10.48 C: Mooney viscosity of copolymer rubber (ML 1+8. tzo℃) If the Q value of the copolymer rubber exceeds the B value, high filling If the physical properties of the vulcanizate in the formulation are not sufficient, and on the other hand, the A value is less than
Mainly, the various workability mentioned above deteriorates.

The copolymer rubber that satisfies the conditions (1) to (4) above is cylindrical.

It can be obtained by copolymerizing ethylene-α-olefin-diolefin in the presence of a catalyst consisting of a combination of an organometallic compound of Groups 1 to 1 of the Periodic Table and a nonadium compound.

The α-olefin used as a monomer for copolymerization is an α-olefin having 3 to 12 carbon atoms.Specific examples include propylene, butene-1,4-methylpeyte:y-1+hexene-1, octane/-1, etc. It is. Preferred is propylene or butene-1. These α-olefins can be used alone or in combination of two or more types.

The diolefins include the following, and one or more of these can be used in combination.

dicyclopentadiene, tricyclopentadiene, 5.
-Methyl-2,5-norbornadiene, 5-methylene-
2-norbornene, 5-ethylidene-2-norbornene, 5-impropylidene-2-norbornene, 5-improbenyl-2-norbornene, 5-(1-7'tenyl)-2-norbornene, cyclooctadiene, vinylcyclohexene , 1.5.9-cyclododecatriene, 6
-Methyl-4,7,8,9-tetrahydroindene.

2.2'-dicyclopentenyl, trans-1,2-divinylcyclobutane, 1-4-hexadiene.

2-methyl-1,4-hexadiene, 1,6-octadiene, 1,7-octadiene, 1,8-nonadiene, 1
, 9-decadiene, 3,6-dimethyl-1,7-octadiene, 4,5-dimethyl-1,7-octadiene, 1
, 4,7-octatriene, 5-methyl-1,8-nonadiene.

Among these non-conjugated diolefins, 5-ethylidene-
2-norbornene and/or dicyclopentadiene are preferred.

In the present invention, the filler is the ethylene-α-olefin of the present invention ~
150 to 100 parts by weight of diolefin copolymer rubber
450 parts by weight, preferably 160 to 350 parts by weight.

If it is less than 150 parts by weight, the mechanical strength will not be sufficient (・45
If it exceeds 0 parts by weight, processability will deteriorate.

The filler used here is carbon black.

Inorganic fillers such as white carbon (silicate compound), calcium carbonate, talc, and clay; organic fillers such as no-styrene resin, coumaron-indene resin, phenol resin, lignin, modified melamine resin, and 90% oil resin. . Among these, inorganic fillers are particularly preferably used.

In the present invention, the softener is the ethylene-α-olefin of the present invention.
Diolefin XX combination 6 for 100JijL part
0 to 250 parts by weight, preferably 100 to 200 parts by weight.

If the weight is less than 60 parts, the processability will not be sufficient, and if the weight exceeds 250 parts, mechanical strength will decrease and the problem of bleeding of the softener will occur, which is disadvantageous.

Softeners used here include process oils, lubricating oils, petroleum-based softeners such as Halafin, liquid paraffin, petroleum asphalt, and petroleum jelly; coal tar-based softeners such as coal tar pitch; castor oil, Fatty oil-based softeners such as linseed oil, rapeseed oil and coconut oil; tall oil; sub; four types such as beeswax, carnauba, and lanolin; ricinoleic acid, palmitic acid, and barium stearate.

Examples include fatty acids and fatty acid salts such as calcium stearate and zinc laurate; synthetic polymeric substances such as petroleum resins;

In particular, petroleum-based softeners and process oils are preferably used. These softeners are ethylene-α-olefin-
It may be blended in the manufacturing process of diolefin copolymer rubber.

In addition, a vulcanizing agent, a vulcanization accelerator, and a dispersing agent as required.

Plasticizer, tackifier, 9 colorants, 2 blowing agents, 1 blowing aid.

A lubricant, an anti-aging agent, and other additives can be used and mixed together.

Vulcanizing agents used for compounding vulcanized rubber include peroxide and
Sulfur, - sulfur compounds such as sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide - selenium dimethyldithiocarbamate.

Examples include metal compounds such as magnesium oxide, zinc white, and red lead. Among these, sulfur or peroxide is preferred. When performing sulfur vulcanization, the amount of sulfur is usually 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the rubber component.
It is used in a proportion of 5 to 5 parts by weight. Additionally, a vulcanization accelerator can be used if necessary. As a vulcanization accelerator, N-
Cyclohexyl-2-benzothiazole-sul7enamide.

N-oxydiethylene-2-penzothiazole-sulfenamide, N-N-diisopropy/l/-2-benzothiazole-sulfenamide/2-mercaptobenzothiazole, 2-(2,4-dinitrophenyl) ) Mercaptobenzothiazole-2-(2,6-diethyl-4-
Thiazoles such as morpholinothio) benzothiazole and benzothiaziludisulnide; guanidines such as diphenylguanidine, triphenylguanidine-di-ortho-tolylguanidine, orun-trilubiguanide, and diphenylnaedine phthalate; acetaldehyde- Aniline reactants Nibutyraldehyde-aniline condensates; aldehyde amines or aldehyde-ammonia systems such as hexamethylene natamine, acetaldehyde ammonia; imidacillin systems such as 2-mercaptoimidacillin; thiocarbanilide, diethylthiourea t diptylthionilia , trimethylthiourea, diorthotolylthiourea, and other thioureas; tetramethylthiuram monosulfide, tetramethylthiuram monosulfide, ζtetraethylthiuram disulfide, tetrabutylthiuram disulfide.

Thiuram series such as dipentamethylenethiuram tetrasulfide; zinc dimethyldithiocarbamate.

Dithioate salts such as zinc diethylthiocarbamate, zinc di-n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate; diptyls Examples include xanthate compounds such as zinc xanthate;

These vulcanization accelerators are usually 0.1 to 20 parts, preferably 0.2 to 10 parts per 100 parts of the rubber component.
Used in parts by weight.

Peroxides used in peroxide vulcanization include dicumyl peroxide, l.1'-di(t-butylperoxy)-
3,3,5-trimethylcyclohexane-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane,
Examples include 2,5-dimethyl-2,5-di(t-butylperoxy)hexy7.

In addition, as a vulcanization aid at that time, sulfur, a sulfur compound such as dipentamethylene thiuram tetrasulfide, and a polyfunctional compound such as ethylene dimethacrylate, dipinylbenzene diallyl phthalate, metaphenylene bismaleimide, and toluylene bismaleimide are used. oxime compounds such as p-quinone dioxime and p.p'-dibenzoylquinone oxime can be used alone or in combination.

Examples of plasticizers include 7 tar acid esters, adipate esters, sebacic acid esters, and phosphoric acid esters.

Tackifiers include coumaron indene resin, terpene-phenol resin, xylene and formalin resin.

Colorants include inorganic and organic pigments.

Foaming agents include sodium bicarbonate/ammonium carbonate, N@N'N ditrosopentamethylenetetramine, azocarbonamide, azobisisobutyronitrile, and benzenesulfonyl hydroxide.

Toluenesulfonyl hydrazide, calcicum azide, para-toluenesulfonyl azide, etc.

As the foaming aid, salicium A/Shun, phthalic acid, urea, etc. can be used.

Depending on the application, other rubber materials such as other ethylene may also be used.
α-olefin rubber, styrene-butashare fA,
Natural rubber, isoprene rubber, polyphtadiene rubber, butyl rubber, halogenated butyl rubber.

A mixture of recycled rubber may be used.

In particular, for waterproof sheet applications, 7 parts of butyl rubber and/or halogenated butyl rubber are added to 10011 parts of the ethylene-α-olefin-diolefin copolymer rubber of the present invention.
By blending 0x@ parts or less, preferably 5 oIrJ parts or less, desirable properties for use in waterproof sheets can be achieved.

The rubber composition of the present invention can be prepared by using the commonly used raw materials.
For example, it can be obtained by kneading using a Banbury mixer or a roll mill. Furthermore, it can be molded into any desired shape using an extruder or calendar roll, and after vulcanization, it can be used in various applications in which ethylene-propylene-diolefin copolymers are generally used.

Example F” The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited to the following embodiments unless the gist thereof is exceeded.

The cyclohexane insoluble content of the copolymer rubber used in the present invention was measured as follows.

Raw material rubber 3I, which does not contain compounding agents, is cut into pieces with a side length of 1 mvn or less, immersed in lOOmJ cyclohexane, and cooled for 48 hours in a thermostat. The insoluble condensate was dried for 1 hour in vacuum at 105° C. and weighed. The weight of the insoluble condensate divided by the weight of the raw rubber was defined as the cyclohexane insoluble content (% by weight).

The Q value was measured as follows.

(1) Using standard polystyrene of known molecular weight (monodispersed polystyrene manufactured by Toyo Soda Co., Ltd.), 2 molecular weights M and its G
PC (Gel Permeation Chrome)
a-tograph) count and 2 molecular weight M
A correlation diagram (calibration curve) between EV (Elution Volume) and EV (Elution Volume) is plotted. The concentration at this time is 0.02 wt%.

The standard polystyrene calibration curve is corrected to the EPDM calibration curve using the universal method.

(Take the GPC pattern of the sample using the 21 GPC measurement method and find out M using the above (1). The sample preparation conditions and GPC measurement conditions at that time are as follows.

Sample preparation (a) Anti-aging agent 2,6- in 0-dichlorobenzene solvent
0.08 weight t of sheet tert-butyl-p-cresol
Add and dissolve.

(b) Aliquot the sample into an Erlenmeyer flask together with o-dichlorobenzene solvent.

(c) Heat the Erlenmeyer flask to 120°C and stir for about 60 minutes to dissolve.

) Apply GPCFc to the solution. In addition, it is automatically passed through a 0.5μ sintered filter in the GPC device.

GPC measurement conditions (a) Equipment i Waters ff150c type (b)
Column Toyo Soda Co., Ltd. H type (c) sample i
500 μm) Temperature: 120°C (e) Flow rate: 1+aJ/m1n (f) Column number of plates: 1×10 to 2×10− (measured value with acetone) Mooney viscosity ('ML 1+9・120°C) was preheated for 1 minute, then measured. Measured for 8 minutes at a temperature of 120℃.

Propylene content (wt%) was measured by infrared absorption spectrum.

Iodine value is measured by titration method.

Tensile stress, tensile strength, elongation, hardness/tear strength (Type B) were measured based on JISK-6301.

The processability of the compounded rubber in a Banbury mixer was evaluated by visually evaluating the state of the compound after discharge from the Banbury, the mixing state of fillers, and the gloss and cohesion of the compound. The results are shown as excellent, good, fair/poor/failed.

The roll processability of the compounded rubber was determined by rolling the unvulcanized compound with a 10-inch roll at a roll temperature of 50°C to 5°C.

Wrapping around a roll with a nip width of 2 mm (tie) K was evaluated based on the length of time required to wind the film and whether the winding state was tight or not. The results are shown as excellent, good/fair, poor, or poor.

After the roll processability test, the surface condition of the sheet sample was evaluated based on the smoothness, gloss, etc. of the surface surface, and the results were rated as excellent, good/fair, poor, or poor.

Examples 1 to 3/Comparative Examples 1 to 3 Rubber compounds were prepared using the copolymer rubbers shown in Table 1 and according to the formulations shown in Table 1-2. The preparation method is to knead the component (a) in Table 2 using a BR type Banbury mixer at a rotor rotation speed of 5 Q rpm + 30°C for 3 minutes, and then knead the component (a) in Table 2 using a 10 inch roll maintained at 50°C. The middle ingredient (b) was mixed for 3 minutes.

The roll rotation speed is 22/28 rp for the front and rear rolls respectively.
It was m. The vulcanization conditions were 160° C. for 30 minutes, and the properties of the obtained vulcanizate are shown in Table 4 along with processability.

As is clear from Table 11 and Table 4, in Examples 1 to 3, t
It exhibits good processability and physical properties with a high loading of 429.2 parts of otal.

On the other hand, in Comparative Example 1, the Q value exceeds the B value, and therefore sufficient vulcanized physical properties cannot be obtained. In Comparative Example 2, on the other hand, the Q value is smaller than the A value, so the workability is significantly deteriorated. Furthermore, in Comparative Example 3, the cyclohexane insoluble content exceeded 15% by weight, resulting in poor processability.

Examples 4-6. Comparative Examples 4 to 6 Comparative Examples 1 to 3 were carried out in the same manner as in Examples 1 to 3, except that the formulation was changed to Table 3 and the vulcanization conditions were changed to 150°C and 25 minutes.

Table-1 (Characteristics of ethylene-α-olefin-diolefin copolymer rubber) Table-2 Blending recipe A: Part vulcanization accelerator N-cyclohexyl-2-benzothiazyl Table-3 Blending recipe B: Part vulcanization accelerator "Effects of the Invention" As is clear from the above, if the rubber composition of the present invention is used,
It is possible to obtain a product that is inexpensive and has excellent workability and mechanical strength, and its industrial value is great. Taking advantage of its effects, the rubber composition of the present invention can be suitably used for automobile parts such as hoses and weather strips, as well as waterproof sheets, belts, and the like.

Claims (1)

[Claims] 1. Ethylene-α that satisfies the following conditions (1) to (4)
- A rubber composition characterized in that 150 to 450 parts by weight of a filler and 60 to 250 parts by weight of a softener are blended with respect to 100 parts by weight of olefin-diolefin copolymer rubber (1) α-olefin The number of carbon atoms is 3 to 12, and the weight ratio of ethylene/α-olefin is 80 to 65/20.
35, the bonding amount of diolefin units is 5 to 25 in terms of iodine value, (2) the Mooney viscosity of the copolymer rubber is ML_1_+_8_
,_1_2_60-280 at 0_℃, (3) The insoluble amount (cyclohexane insoluble portion) when the copolymer rubber is dissolved in cyclohexane at 30℃ is 15% by weight or less, (4) The weight average molecular weight of the copolymer rubber/ Number average molecular weight (Q
value) is greater than or equal to the A value and less than the B value calculated by the following formula A = 0.042 x C - 2.34 B = 0.042 x C + 0.48 _1_2_0_℃) 2. Claim 1, characterized in that 70 parts by weight or less of butyl rubber and/or halogenated butyl rubber is blended with 100 parts by weight of the ethylene-α-olefin-diolefin copolymer rubber. Rubber composition described