JPS6142738B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vulcanizate of highly fluid ethylene copolymer rubber. Ethylene-propylene copolymer rubber (EPR) or ethylene-propylene-polyene copolymer rubber (EPT) has excellent heat resistance, weather resistance, and low-temperature properties, so it is used in electric wires, automobile parts, construction and civil engineering parts, and industrial products. It is used as a material such as However, the commonly used EPR and EPT
had poor fluidity and was difficult to injection mold into large molded products. Efforts have been made to increase fluidity during processing, such as adding oil or increasing processing temperature, but this can lead to undesirable damage such as deterioration of the physical properties of molded products and occurrence of burns during processing. This phenomenon caused many problems in practical use.
To improve these drawbacks, low molecular weight EPR
It has also been proposed to use vulcanized rubber or EPT, but since vulcanized rubber with high strength cannot be obtained when such rubber is vulcanized, the field of use has been severely restricted. The present inventors searched for a rubber that has high fluidity and can be injection molded, cast molded, or extruded, and also exhibits high breaking strength when vulcanized. As a result, the following ethylene copolymer They discovered that rubber has both of these properties. That is, according to the present invention, (A) is composed of ethylene and an α-olefin having 4 to 10 carbon atoms, and in some cases further contains a polyene, and (B) ethylene/the α-olefin (molar ratio) is
86/14 to 95/5, (C) Intrinsic viscosity [η] measured in decalin at 135°C is 0.1 or more and less than 1.0 d/g, (D) Melt viscosity η _B at 100°C is 1 × 10 ² to 1 ×10 ⁵ poise, (E) Melting point Tm based on differential scanning calorimetry (DSC) thermal analysis is less than 100℃, (F) Weight average molecular weight/number average molecular weight (Q value)
A vulcanized rubber obtained by vulcanizing an ethylene copolymer rubber having a molecular weight of 2.5 or less is provided. In the present invention, ethylene and carbon atoms having 4 to 4 carbon atoms are used.
A copolymer rubber consisting of 10 α-olefins and optionally further polyenes is used. Examples of the α-olefin having 4 to 10 carbon atoms include one or more of 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, and 4-methyl-1-pentene. Among them, 1-butene is a preferred α-olefin. If propylene is used instead of these α-olefins, a vulcanized rubber with high strength cannot be obtained, so it is excluded in the present invention. The polyene component is not essential, and may be absent when vulcanizing with peroxide, for example, but becomes an essential component when vulcanizing with sulfur. Polyene components include 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5
-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene -2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5
- non-conjugated dienes such as isopropenyl-2-norbornene, 2,3-diisopropylidene-5-
norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-
Typical examples include trienes such as 2,5-norbornadiene, 1,3,7-octatriene, and 1,4,9-decatriene. The content of the polyene component is usually 50 or less, preferably 30 or less, expressed as the iodine value of the copolymer rubber. Another factor controlling the strength of the vulcanized rubber is the ethylene/α-olefin molar ratio, which in the case of the copolymer rubber of the present invention must be at least 86/14. However, if the ratio of ethylene is too large, the vulcanized rubber becomes too hard and loses its rubbery properties, so the molar ratio is usually 86/14 to 95/5, preferably 87/13 to 94/6. Vulcanized rubbers with an ethylene ratio smaller than the above range are excluded from the present invention because the strength of the vulcanized rubber is not high. In order for ethylene copolymer rubber to have high fluidity, the intrinsic viscosity measured in decalin at 135°C must be 0.1.
or less than 1.0d/g, preferably 0.2 or less
0.8d/g, also measured with a B-type viscometer
Melt viscosity η _B at 100°C is 1×10 ² to 1×
10 ⁵ poise, preferably 1×10 ² to 5×10 ⁴ poise. If [η] or η _B is larger than the above range, the fluidity is low, so it cannot be said that the molding processability such as extrusion molding, cast molding, injection molding, etc. is good.
Also, if [η] or η _B is smaller than the above range,
This is not preferred because the strength of the vulcanized rubber is too low. The ethylene copolymer rubber used in the present invention must have a low melting point, and the melting point based on DSC thermal analysis is
It should be below 100°C, preferably below 80°C. It is also necessary to have rubber-like softness, and the hardness Hs measured with a JISA spring hardness meter based on JISK6301 is usually less than 95, preferably 90.
less than Other important properties that ethylene copolymer rubber should have are weight average molecular weight/number average molecular weight (Q
value) and must be less than or equal to 2.5. This is because even if a rubber having a Q value larger than 2.5 is vulcanized, a vulcanized rubber with high strength cannot be obtained. The Q value is measured as follows according to "Gel Permeation Chromatography" written by Takeuchi and published by Maruzen. (1) Using standard polystyrene with a known molecular weight (monodispersed polystyrene manufactured by Toyo Soda Co., Ltd.), measure the molecular weight M and its GPC (Gel Permeation Chromatograph) count, and calibrate the correlation diagram between the molecular weight M and EV (Elution Volume). Create a curve. The concentration at this time is 0.02wt%. (2) Obtain a GPC pattern of the sample using the GPC measurement method, and find M using the above (1). The sample preparation conditions and GPC measurement conditions at that time are as follows. <Sample Preparation> (a) Aliquot the sample into an Erlenmeyer flask together with o-dichlorobenzene solvent to a concentration of 0.04 wt%. (b) Add 0.1 wt% of the anti-aging agent 2,6-di-tert-butyl-p-cresol to the polymer solution in the Erlenmeyer flask containing the sample. (c) Heat the Erlenmeyer flask to 140°C and stir for about 30 minutes to dissolve. (d) Then, pass through a 1 μm Millipore filter at 135°C to 140°C. (e) Apply the liquid to GPC. <GPC measurement conditions> Measurement was carried out under the following conditions. (B) Equipment Waters 200 type (B) Column Toyo Soda S-type (Mix type) (C) Sample amount 2ml (D) Temperature 135℃ (E) Flow rate 1ml/min (F) Column total Number of theoretical plates: 2 x 10 ⁴ - 4 x 10 ⁴ (Actually measured value in acetone) Generally, a method of producing a rubbery substance by copolymerizing ethylene and α-olefin tyrene having 3 or more carbon atoms, and in some cases further polyene. It is widely known that in order to produce a low molecular weight rubber, a molecular weight regulator such as hydrogen may be present. However, as mentioned above
In order to obtain an ethylene copolymer rubber that satisfies all conditions (A) to (F), extremely limited catalyst systems and polymerization conditions must be selected. An example of the manufacturing conditions is as follows. First, as a catalyst, VO(OR) _o X _3-o (where R is an aliphatic hydrocarbon group,
Al/ _V ( In the presence of a large amount of hydrogen in a hydrocarbon solvent, maintaining the atomic ratio (atomic ratio) at 5 or more,
At temperatures between 40℃ and 100℃, ethylene and carbon number 4
to 10 α-olefins, or they and polyenes may be continuously polymerized. Specific examples of vanadium compounds represented by the above general formula include VO( _OCH3 ) _Cl2 , VO( _OCH3 ) _2Cl ,
VO( _OCH3 ) ₃ , VO( _{OC2H5 ) Cl2 , VO ( OC2H5 ) 1.5 Cl1.5} , VO( _{OC2H5 ) 2Cl} , VO( _OC2H5 ) ₃ , VO(OC ₂ H ₅ ) _{1.5 Br 1.5} , VO(OC ₃ H ₇ ) Cl _{2 ,} VO(OC ₃ H _{7 ) 1.5} Cl _{1.5 ,} VO(OC ₃ H ₇ ) ₂ Cl , VO( _{OC3H7 ) 3 , VO} (On _- C4H9)Cl2, VO ₍ On- _C4H9 ) _2Cl , VO(O- _{isoC4H9 ) 2Cl} , VO(O- _Examples include _{secC4H9 ) 3 ,} VO( _{OC5H11 ) 1.5Cl1.5} , or _a mixture thereof. Among these, those in which n in the above formula is in the range of 1≦n≦2 are particularly preferred, and vanadium compounds in which R is C ₂ H ₅ are preferably used. These are for example
Reacting VOCl ₃ with alcohol, or
It can be easily produced by reacting _VOCl3 and VO(OR) ₃ . Further, the organoaluminum compounds _represented by the above formula include, for example _, R′AlX ₂ , R′ _1.5 AlX _1.5 , R _{′ 1.5} AlX′ _{1.5 and}
A mixture of R′AlX′ ₂ , a mixture of R′AlX′ ₂ and R′ ₂ AlX′,
These include a mixture _of R′AlX′ ₂ and R _{′ 1.5 AlX} ′ _1.5 and R′ ₂ AlX′. More specifically _{, C2H5AlCl2 ,
( C2H5 ) 1.5AlCl1.5} , _{a mixture of C2H5AlCl2 and} ( _C2H5 ) _{1.5AlCl1.5 in a proportion that} satisfies the above formula;
A mixture _of isoC ₄ H ₉ AlCl ₂ and (isoC ₄ H _{9 ) 1.5 AlCl 1.5} ,
Examples include a mixture of (C ₂ H _{5 )} AlCl ₂ and (isoC ₄ H ₉ ) _{1.5 AlCl 1.5 .} The usage ratio of the vanadium compound and the organoaluminum compound is such that Al/V (atomic ratio) is 5 to 5.
100, preferably in the range of 5 to 50. The hydrocarbon solvent used in the polymerization may be aliphatic, alicyclic or aromatic, but aliphatic solvents are particularly preferred. Specific examples include pentane, hexane, heptane, octane, decane, and kerosene. The polymerization is preferably carried out at 0 to 100°C, particularly preferably at 40 to 90°C, under conditions where the copolymer rubber is dissolved.
It is carried out at a temperature of °C. The polymerization pressure varies depending on the reaction temperature, but is generally 0 to 50 kg/cm ² , preferably 0 to 20 kg/cm ² . The copolymerization is preferably carried out at a concentration of the vanadium compound in the hydrocarbon solvent of 0.01 to 5 mmol/, in particular 0.1 to 4 mmol/. In copolymerization, it is preferable to adjust the intrinsic viscosity of the copolymer rubber by adjusting the amount of hydrogen used. The amount of hydrogen used is usually such that the molar ratio of hydrogen to ethylene in the gas phase of the reactor is 5/95 to 95/5. For the copolymerization, it is preferable to adopt continuous polymerization in which a catalyst, a solvent, a monomer, hydrogen, etc. are continuously supplied, and a polymerization liquid, unreacted raw materials, etc. are continuously discharged. By adopting the above conditions, (A)
A copolymer rubber satisfying ~(F) can be obtained. In the present invention, such a copolymer rubber is preferably blended with a vulcanizing agent, subjected to extrusion molding, cast molding, injection molding, etc., and then vulcanized. Since a copolymer rubber that satisfies (A) to (F) above is used, it has good fluidity during molding, so it can be molded at low temperatures in the same manner as ordinary thermoplastic resins. Vulcanizing agents used in vulcanized rubber compounding include peroxide, sulfur, sulfur monochloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, selenium dimethyldithiocarbamate. Examples include sulfur compounds such as, magnesium oxide, zinc white, red lead, and other metal compounds. Among these, sulfur or peroxide is preferred. When performing sulfur vulcanization, the amount of sulfur is usually 0.1 to 10 parts by weight per 100 parts by weight of the rubber component.
It is used in proportions by weight, preferably from 0.5 to 5 parts by weight. Additionally, a vulcanization accelerator can be used if necessary. As the vulcanization accelerator, N-cyclohexyl-2-benzothiazole-sulfenamide,
N-oxydiethylene 2-benzothiazole-sulfenamide, N,N-diisopropyl-2-
Benzothiazole sulfenamide, 2-mercaptobenzothiazole, 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-
Thiazoles such as (2,6-diethyl-4-morpholinothio)benzothiazole and benzothiazyl-disulfide; guanidines such as diphenylguanidine, triphenylguanidine di-ortho-tolylguanidine, ortho-tolyl Γ biguanite, diphenylguanidine phthalate Acetaldehyde-aniline reaction product: Butyraldehyde-aniline condensate; Aldehyde amine or aldehyde-ammonia systems such as hexamethylenetetramine and acetaldehyde ammonia; Imidazoline systems such as 2-mercaptoimidazoline: thiocarbanilide, diethylthiourea, dibutylthiourea, Methylthiourea, di-ortho-
Thiourea series such as tolylthiourea: Thiuram series such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, dibentamethylenethiuram tetrasulfide; dimethyl Zinc dithiocarbamate,
Dithioate salts such as zinc diethylthiocarbamate, zinc di-n-butylthiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate, and tellurium diethyldithiocarbamate. and xanthate-based compounds such as zinc dibutylxanthate. These vulcanization accelerators are usually 0.1 to 20 parts by weight, preferably 0.2 to 20 parts by weight, per 100 parts by weight of the rubber component.
Used in a proportion of 10 parts by weight. When sulfur vulcanization is performed, an ethylene copolymer rubber containing a polyene component is used. Ethylene copolymer rubbers with or without polyene components can be vulcanized in peroxide vulcanization systems. Peroxides used for this purpose include dicumyl peroxide, 1,1'-di(t
-butylberoxy)3,3,5-trimethylcyclohexane, di(t-butylberoxy)diisopropylbenzene, 2,5-dimethyl-2,5
-di(t-butylberoxy)hexane, 2,5
-dimethyl-2,5-di(t-butylberoxy)hexyne and the like. In addition, as a vulcanization aid at that time, sulfur, sulfur compounds such as dipentamethylenethiuram tetrasulfide, polyesters such as ethylene dimethacrylate, divinylbenzene, diallyl phthalate, metaphenylene bismaleimide, and toluylene bismaleimide are used. Functional monomer, p-quinone dioxime,
Oxime compounds such as p,p'-dibenzoylquinone oxime can be used alone or in combination. When performing the above vulcanization, other additives such as activators, dispersants, fillers, plasticizers, tackifiers, colorants, foaming agents, foaming aids, lubricants, anti-aging agents, and other additives may be added as necessary. Can be used together. Fillers include inorganic fillers such as carbon black, white carbon (silicic acid compounds), calcium carbonate, talc, and clay; organic fillers such as high styrene resin, coumaron indene resin, phenolic resin, lignin, modified melamine resin, and petroleum resin. Mention may be made of fillers. Among these, inorganic fillers are particularly preferably used. Softeners include process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petroleum-based softeners such as petrolatum; coal tar-based softeners such as coal tar and coal tar pitch; castor oil, linseed oil, and rapeseed oil. , fatty oil-based softeners such as coconut oil; tall oil; sub; waxes such as beeswax, carnauba wax, and lanolin; ricinoleic acid,
Fatty acids and fatty acid salts such as palmitic acid, barium stearate, calcium stearate, and zinc laurate; Synthetic polymeric substances such as petroleum resins;
can be mentioned. Plasticizers include phthalate esters, adipate esters, sebacate esters, phosphoric acid, etc. Tackifiers include coumaron indene resin, terpene/phenol resin, xylene/
Colorants such as formalin resin, inorganic and organic pigments, blowing agents such as sodium bicarbonate, ammonium carbonate, N,N'-dinitrosopentamethylenetetramine, azocarbonamide, azobisisobutyronitrile, benzene. Sulfonyl hydrazide, toluenesulfonyl hydrazide, calcium azide, para-toluenesulfonyl azide, etc. As the foaming aid, salicylic acid, phthalic acid, urea, etc. can be used. Vulcanization conditions vary depending on the type of vulcanizing agent, but
Usually 80 to 250℃, preferably 100 to 200℃
for 1 to 60 minutes, preferably 1 to 40 minutes at a temperature of
It is best to do this for a minute. In particular, when performing peroxide vulcanization, the vulcanization time is preferably about four times the half-life of the peroxide. The vulcanized rubber of the present invention has a tensile strength at break of usually 40 Kg/cm ² or more, especially 50 Kg/cm ² or more when measured according to JISK6301 even when no filler is blended. The elongation at break is 200% or more, especially 250% or more. When a filler is added, the properties are further improved. Hereinafter, it will be explained in more detail with reference to Examples. Example 1 A ternary copolymerization reaction of ethylene, 1-butene, and dicyclopentadiene was continuously carried out using 15 stainless steel polymerization vessels equipped with stirring blades. That is, hexane is continuously supplied as a polymerization solvent from the top of the polymerization vessel at a rate of 5 per hour. On the other hand, the polymerization liquid is continuously drawn out from the lower part of the polymerization vessel so that the polymerization liquid in the polymerization vessel is always 5. As a catalyst, (A) a reaction product of vanadium oxytrichloride and ethyl alcohol (prepared in a catalyst preparation container so that the molar ratio of vanadium oxytrichloride to ethyl alcohol was 1/1.5) was added in a polymerization vessel. Also, (B) ethylaluminum sesquichloride [(C ₂ H _{5 ) 1.5} AlCl _1.5 ] and ethylaluminum dichloride [(C _{2 H 5 )} AlCl ₂ ) (the molar ratio of ethylaluminum sesquichloride and ethylaluminum dichloride is 7/
3) were continuously fed into the polymerization vessel from the top of the polymerization vessel so that the concentration of aluminum atoms in the vessel was 10 mmol. Additionally, a mixed gas of ethylene and 1-butene (60 mol% ethylene, 40 mol% 1-butene) is supplied from the top of the polymerization reactor at a rate of 500 mol% per hour, and hydrogen gas is supplied as a molecular weight regulator at a rate of 4.0 mol% per hour. Cyclopentadiene is continuously fed from the top of the polymerization vessel at a rate of 25 g/hour. The copolymerization reaction was carried out at 60°C by circulating hot water through a jacket attached to the outside of the polymerization vessel. In this case, the pressure inside the polymerization vessel was 7.8 Kg/cm ² (gauge). When the copolymerization reaction is carried out under the conditions described above, an ethylene/1-butene/dicyclopentadiene copolymer is obtained in a uniform solution state. A small amount of methanol was added to the polymerization liquid taken out from the bottom of the polymerization vessel to stop the polymerization reaction, and the polymer was taken out by steam stripping treatment, and then heated to 80°C.
It was dried under reduced pressure for one day and night. Through the above operations, an ethylene/1-butene/dicyclopentadiene copolymer was obtained at a rate of 240 g/hour. The ethylene content of the copolymer measured by infrared absorption spectrometry was 91.5 mol%, and the intrinsic viscosity [η] measured in decalin at 135°C was 0.43 d/
g, the melt viscosity at 100℃ measured with a B-type viscometer η _B is
7.1×10 ³ poise, iodine value 10.2, melting point by DSC
Tm was 45°C, and Q value by GPC was 2.0. The copolymer was sulfur vulcanized by the following method. 100 parts by weight of the obtained copolymer, 5 parts by weight of zinc white, 1.0 parts by weight of stearic acid, 1.5 parts by weight of sulfur,
A blend was prepared by kneading 1.0 part by weight of mercaptobenzothiazole, 0.5 part by weight of tetramethylthiuram disulfide, and 0.5 part by weight of dipentamethylenethiuram tetrasulfide for 20 to 30 minutes using two rolls. The obtained compound was press-vulcanized at 130° C. for 40 minutes, and the physical properties of the obtained vulcanizate were measured according to JISK6301. The strength at break of the vulcanizate is
110Kg/cm ² , elongation at break 400%, hardness according to JISA
Hs was 78. The copolymer was also peroxide vulcanized by the following method. Using two rolls, 100 parts by weight of the obtained copolymer, 5 parts by weight of zinc white, 1.5 parts by weight of stearic acid, 2.7 parts by weight of dicumyl peroxide, and 3.5 parts by weight of p,p'-dibenzoylquinone oxime were mixed. te20
A blend was prepared by kneading for ~30 minutes, and press vulcanization was performed at 160°C for 30 minutes. Physical properties of vulcanizate according to JISK6301
Measured by. The strength at break of the vulcanizate is 105
Kg/ ^cm2 , elongation at break 280%, hardness Hs according to JISA
was 78. Examples 2 to 8, Comparative Examples 1 to 4 The same procedure as in Example 1 was conducted except that the polymerization conditions were changed as shown in Table 1. The obtained copolymer was prepared in Example 1.
The same formulation as above was carried out, vulcanization was carried out in the same manner as in Example 1, and the physical properties were measured. The results are shown in Table 2.

【table】

【table】

【table】

[Table] Example 9 In Example 1, instead of dicyclobentadiene, 5-ethylidene-2-
The same operation was repeated except that norbornene was supplied, and a copolymer was obtained at a rate of 250 g/hour. The ethylene content of the copolymer is 91.0 mol%, the intrinsic viscosity [η] is 04d/g, and the melt viscosity η _B is 6.8×10 ³
Poise, iodine value 11.2, melting point Tm 44℃, Q value
It was 1.9. The copolymer was blended in the same manner as in Example 1,
A vulcanization operation was performed and physical properties were measured. In the case of sulfur vulcanization, strength at break is 118 kg/cm ² and elongation at break is 400.
%, Hs was 77. In the case of peroxide vulcanization,
Strength at break 108Kg/cm ² , elongation at break 290%, Hs77
It was warm. Further, a vulcanized product was obtained in the same manner as above, except that 30 parts by weight of carbon black (SEAST H, manufactured by Tokai Electrode Co., Ltd.) was added to the above-mentioned blending and vulcanization operations. Physical property measurements showed that in the case of sulfur vulcanization, the strength at break was 130 Kg/cm ² , the elongation at break was 400%,
It was Hs85. In the case of peroxide vulcanization, the strength at break was 115 Kg/cm ² , the elongation at break was 300%, and Hs was 85.

Claims (1)

[Scope of Claims] 1 (A) consisting of ethylene and an α-olefin having 4 to 10 carbon atoms, and optionally further polyene; (B) ethylene/the above α-olefin (molar ratio);
86/14 to 95/5, (C) Intrinsic viscosity [η] measured in decalin at 135°C is 0.1 or more and less than 1.0 d/g, (D) Melt viscosity η _B at 100°C is 1 × 10 ² to 1 ×10 ⁵ poise, (E) Melting point Tm based on differential scanning calorimetry (DSC) thermal analysis is less than 100℃, (F) Weight average molecular weight/number average molecular weight (Q value)
Vulcanized rubber made by vulcanizing ethylene copolymer rubber of 2.5 or less. 2. The vulcanized rubber according to claim 1, which contains a filler. 3 Breaking point strength of at least 40Kg/ ^cm2 and 200
The vulcanized rubber according to claim 1 or 2, which has an elongation of % or more. 4. The vulcanized rubber according to claim 1, 2 or 3 in the form of an extrusion molded product, a cast molded product or an injection molded product.