JPS59213743A - Vulcanizable rubber composition - Google Patents

Abstract

PURPOSE:The titled composition, obtained by incorporating chloroprene rubber with a specific halogenated ethylene-alpha-olefin copolymeric rubber in a specific proportion, having improved ozone resistance and cold resistance, and capable of giving vulcanizates suitable for electric wires, automotive industrial parts, etc. CONSTITUTION:A vulcanizable rubber composition obtained by incorporating (A) chloroprene rubber with (B) a halogenated ethylene-alpha-olefin copolymeric rubber having 3-20, preferably 5-10 iodine value, preferably 20-30wt% halogen content and about 40-100 Mooney viscosity at (95/5)-(20/80), preferably (85/15)- (40/60) weight ratio between the components (A) and (B), and adding if necessary a filler or softening agent thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vulcanizable rubber composition, and more particularly to a vulcanizable rubber composition in which the ozone resistance and low-temperature properties of chloroprene rubber are improved.

Chloroprene rubber is widely used as a rubber material with a good balance of strength, heat aging resistance, oil resistance, etc., but it has the disadvantage of poor ozone resistance and cold resistance. Therefore, it is recommended to incorporate anti-aging agents to improve ozone resistance, and various grades with reduced crystallization speed are on the market to improve cold resistance, but none of these are sufficient to solve the problem.

An object of the present invention is to provide a vulcanizable rubber composition that improves the above-mentioned drawbacks without impairing the strength, heat aging resistance, oil resistance, etc. of chloroprene rubber. As a result of various studies, the inventors of the present invention found that this objective was achieved by mixing chloroprene rubber (A), VCC10, halogenated ethylene/α-olefin copolymer rubber (B) at a weight ratio of A/B=9515 to 20/80. He discovered scales and completed the invention.

The production of the chlorinated ethylene/α-olefin copolymer rubber, which is the component CA) of the present invention, can be carried out by, for example, crushing the ethylene/α-olefin copolymer rubber into fine particles, and converting the fine particles into aqueous suspension 1@VCL. In this method, the copolymer rubber is dissolved in a chlorine-stable solvent such as carbon tetrachloride or tetrachlorethylene, and the molecules are dissolved in a uniform solution state. This is done by contacting with chlorine, etc. At this time, if molecular bromine is used instead of molecular chlorine, brominated ethylene and
An α-olefin copolymer rubber is obtained.

Next, the obtained halogenated rubber is preferably heat treated, and the b0 heat treatment is usually 160 to 250 tZ'.

Preferably it is carried out at a temperature of about 170 to 26 OC. At this time, it is preferable that oxygen is not present, for example, in a nitrogen pig enclosure. As the method of heat treatment, ordinary open heating, steam heating, etc. can be used, but continuous heat treatment can also be performed by using a heating mixer such as an extruder and a transfer means. A heat treatment time of about 2 to 60 minutes is generally sufficient.

This heat treatment significantly increases the vulcanization rate, so
Heat treatment is useful in increasing co-vulcanization with chloroprene rubber to a practical level pressure.

Halogenated ethylene φ which is component CB) of the composition of the present invention
The chlorine or bromine content of α-olefin copolymer rubber is 5
It is preferably 65% by weight, more preferably 2% by weight.
It is 0 to 60% by weight. If the halogen content is less than 5% by weight, the compatibility with chloroprene rubber will be low, making it impossible to obtain the desired strength, while if it is more than 65% by weight, the cold resistance will not be sufficiently improved. It has the following drawback.

Next, the iodine value of this halogenated ethylene/α-olefin copolymer rubber is preferably 1 to 20, more preferably 5 to 10. When the iodine number is less than 6, the vulcanization rate is not sufficient, and when the iodine number is more than 20, the effect of improving ozone resistance is not sufficient.

The degree of halogenation can be adjusted by adjusting the amount of halogenating agent used, reaction time, reaction temperature, presence or absence of catalyst or light irradiation, etc.
Although it is possible to some extent, ethylene/α-olefin copolymer rubber (EPDI) containing a non-conjugated diene component as the third component
If) In K, halogen addition occurs preferentially to double bonds, and since the double bond content is low, the double bonds disappear in most cases. Therefore, the above heat treatment is extremely important for the chlorinated or brominated EPDH of the present invention.

Next, the Mooney viscosity [AfL1+l+(100C)] of the halogenated ethylene/α-olefin copolymer rubber is preferably about 20 to about 150, more preferably about 40 to about 100. If the viscosity is too high, the plasticity will be lost, resulting in difficulty in processing, and if the Mooney viscosity is too low, the strength of the vulcanized rubber will be low.

In the present invention, it is most important to use chloroprene rubber (CA) in combination with halogenated ethylene and α-olefin copolymer rubber (CB) in order to achieve the objective. Chloroprene rubber (,4) provides excellent oil resistance to vulcanizates, and halogenated ethylene/α-olefin copolymer rubber CB
) provides ozone resistance and cold resistance to the vulcanizate.

The blending ratio of chloroprene rubber (A) and halogenated ethylene-α-olefin copolymer rubber (B) can be arbitrarily selected depending on the use of the composition of the present invention, but the weight ratio is usually A/
B=9515 to 20/80, preferably 8'
It is 5/15 to 40/60. If the ratio of halogenated ethylene α-olefin copolymer rubber CB) is too small, the original purpose of improving ozone resistance cannot be achieved.
In addition, if it is too large, there will be a problem that the oil resistance, which is an excellent feature of chloropre/rubber, will be impaired.

When obtaining a vulcanizate from the composition of the present invention, the copolymer rubber A
In addition to copolymer rubber B, the types and amounts of rubber reinforcing agents, fillers, and softeners, as well as the types of compounds constituting the vulcanization system such as vulcanizing agents, vulcanization accelerators, and vulcanization aids. and the amount, and the process for producing the vulcanizate are selected as appropriate.

In the present invention, chloroprene rubber CA)
,! : The total amount of halogenated ethylene/α-olefin copolymer rubber CB) is appropriately selected depending on the intended performance and use of the vulcanizate, but is usually over 200 parts by weight, preferably over 255 parts by weight.

The softening agent that can be used in the present invention is usually a softening agent used for rubber, but examples include process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petroleum softeners such as petrolatum, coal tar, coal tar, etc. Coal tar-based softeners such as pitch, fatty oil-based softeners such as castor oil, linseed oil, rapeseed oil, coconut oil, tall oil;
Sub: Waxes such as beeswax, carnauba wax, and lanolin; Fatty acids and fatty acid salts such as ricinoleic acid, palmitic acid, barium stearate, calcium stearate, and zinc laurate; Synthesis of petroleum resins, atactic polypropylene, coumaron-inthene resins, etc. Examples include polymeric substances, ester plasticizers such as dioctyl adipate and dioctyl phthalate, microcrystalline wax, and factice.

The blending amount of these softeners can be appropriately selected depending on the use of the vulcanizate, but the total amount of chloroprene rubber (A) and halogenated ethylene/α-olefin copolymer comb (B) is 100%.
Up to 150 parts by weight, preferably up to 100 parts by weight
Parts by weight are added.

In the present invention, SRF, Gl)F, FEF, llAl? .

I S AFSS AF, F 7'SMT l-Tono force M: /7' Using lac and rubber reinforcing agents such as finely divided silicic acid and fillers such as light calcium carbonate, heavy calcium carbonate, talc, clay, etc. Good too.

The type and amount of these rubber reinforcing agents and light cutting agents are appropriately selected depending on the use, but chloroglene rubber CA)
,! : Halogenated ethylene/α-olefin copolymer rubber (mixed in a proportion of at most 00 parts by weight, preferably at most 200 parts by weight, based on 100 parts by weight of the total amount with ID).

The vulcanizate obtained from the composition of the present invention is prepared by preparing an unvulcanized rubber compound by the method described below, in the same way as when general rubber is usually vulcanized, and then molding the compound rubber into the intended shape. After that, it is manufactured by vulcanization. As a vulcanization method, there are a method of heating using a vulcanizing agent and a method of irradiating with an electron beam.

Examples of the vulcanizing agent used include metal salts, sulfur-based compounds, organic peroxides, and combinations thereof. Examples of metal salts include magnesia, zinc white, higher fatty acid zinc, such as zinc stearate,
Zinc oleate, red lead, resurge, etc. are used. The amount of metal salt to be blended is usually selected to be 5 to 20 parts by weight based on 100 parts by weight of the total amount of chloroprene rubber (CA), halogenated ethylene◆α-olefin copolymer rubber (CB).

Examples of sulfur-based compounds include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfite, tetramethylthiuram disphite, dimethyl moiety selenium carbamate, and the like.

The amount of sulfur compound is chloroprene rubber <A) and halogenated ethylene/α-olefin copolymer rubber CB.
), the ratio is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight.

Examples of organic peroxides used in the vulcanization of the composition of the present invention include dicumyl peroxide, 2,5-dimethyl-2,5-
Di(tert-butylperoxyrahexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2
．． 5-dimethyl-2゜5-diCM-tributylperoxy)
Examples include hexyne-6, di-tert-butyl peroxide, di-tert-butylperoxy-3,3,5-)limethylcyclohexane, and tert-butyl hydroperoxide, among which dicumyl peroxide, di-tert-butyl peroxide, and Tert-butylperoxy-6,3°5-trimethylcyclohexane is preferably used. The amount of organic peroxide used is usually 3X10-' to 5X1 per 100 parts by weight of the total amount of chloroprene rubber (/f) and hyhalogenated ethylene-α-olefin copolymer rubber CB) of the present invention.
0 bemol parts, preferably 1 x 10''3 to 3 x 10
−2 molar parts.

When using a sulfur-incompound with a vulcanizing agent, it is preferable to use a vulcanization accelerator in combination.As a vulcanization accelerator, N-cyclohexyl-2-benzothiazole-sulfenamide is used. , N-oxydiethylene-2-benzothiazole-sulfenamide, N,N-diisopropyl-2-
Benzothiazole sulfenamide, 2-mercaptobenzothiazolepe2-(2,4-di=)rophenyl)mercaptobenzothiazole, 2-(2,6-ethyl-4-morpholinothio)benzothiazole, dibenzothiazyl-disulfide, etc. Thiazole series; diphenylguanidine, triphenylguanidine, thiontril guanidine, orthotolyl e-pi-guanide, diphenylguanidine-phthalate, and other guanidine series: acetaldehyde-aniline reaction product, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde Aldehyde amines or aldehyde-ammonia systems such as ammonia; imidacillin systems such as 2-mercaptoimidacillin; thiourea systems such as thiocarbamic acid, diethylthiourea, dibutylthiourea, trimethylthiourea, and diorntylthiourea; tetra Thiuram-based zinc dimethyldithiocarbamate, zinc diethylthiocarbamate, such as methylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetradrasulfide,
Dithioic acid salts such as zinc di-lupthyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, etc. xanthate such as dibutylxandrozate/zinc acid Examples include systems. The amount of these vulcanization accelerators used is usually 0.1 to 20 parts by weight, preferably 0.1 to 20 parts by weight, based on 100 parts by weight of the total amount of chloroprene rubber (A) and U halogenated ethylene/α-olefin copolymer rubber (B). Return to a proportion of 2 to 10 parts by weight.

When using an organic peroxide as a vulcanizing agent, it is preferable to use a vulcanizing aid in combination. Vulcanization aids and 17 include sulfur, quinone dioximes such as p-quinone dioxime, methacrylates such as polyethylene glycol dimethacrylate, allyls such as diallyl phthalate and triallyl cyanurate, other maleimides, and divinylbenzene. Illustrated. Such a vulcanization aid is used in an amount of 1 to 2 moles, preferably about equal moles, per mole of the organic peroxide used.

Further, by using an anti-aging agent, it is possible to extend the material life of the vulcanizate obtained from the composition of the present invention, as in the case of ordinary rubber. Antioxidants used in this case include aromatic secondary amines such as evaphenylnaphthylamine, N+N'-di-2-naphthyl-p-phenylenediamine, dibutylhydroxytoluene, tetrakis[methylene (6t5-di- Sterically hindered, phenolic stabilizers such as t-butyl-4-hydroxy)hydrocinnamate comethane are used. The usage amount of such anti-aging agent is chloroprene rubber CA)
and halogenated ethylene eα-olefin copolymer rubber CB), usually 0.1 to 5 parts per 100 parts by weight of the total amount.
The proportion is selected to be 0.5 to 6 parts by weight, preferably 0.5 to 6 parts by weight.

Unvulcanized compounded rubber is usually prepared by the following method.

In other words, use a mixer such as a Panbury mixer.
Chloroprene rubber (A), chlorogenated ethylene α-
After kneading the olefin rubber (B), filler and softener at a temperature of 800 to 150C for 6 to 10 minutes, a vulcanizing agent, a vulcanization accelerator or After additionally mixing a vulcanization aid and mixing at a roll temperature of 40 to 80 tT for 5 to 60 minutes,
The compound rubber is prepared in the form of a ribbon or sheet.

The compounded rubber thus prepared is molded into the desired shape using an extruder, calendar roll, or press, and at the same time as the molding or the molded product is introduced into a vulcanization tank and heated at a temperature of 160 to 2°C. A vulcanizate can be obtained by heating for 60 minutes.

This vulcanization step may be performed using a mold or without a mold. When a mold is not used, the molding and vulcanization processes are usually continuous.Heating methods for the vulcanized layer include hot air, glass beads fluidized bed, U, HF (very high frequency electromagnetic waves), steam, etc. Layers can be used.

The vulcanized product produced as described above is useful as such as electric wires, automobile industry parts, civil engineering and construction materials, etc., or a foamed product can be produced by adding a foaming agent to the unvulcanized rubber compound. , it is useful as insulation, cushioning, sealing, etc.

When used as an electric wire, it can generally be used as an insulating material at a voltage of 600V or less. Furthermore, by taking advantage of the heat resistance, bending resistance, etc. of chlorobutene rubber, it can be suitably used as a covering material for electrically insulating materials.

Examples of automotive industrial parts include hose frames such as radiator hoses and fuel hoses, exterior parts such as bumpers and bumper fillers, various weatherst IJ fittings, boots, and ball joint seals. Further, as civil engineering and building materials, it can be used, for example, as construction gaskets, highway joint seals, etc.

Furthermore, in order to produce a foam from the composition of the present invention, a blowing agent and, if necessary, a blowing aid are added.

Blowing agents used include inorganic blowing agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrite; N,N'-dimethyl N, N'-dinitron φ terephthalamide, #
, N'-dinitroso. Nitroso compounds such as pentamethylene/tetramine; azo compounds such as azodicarbonamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate; benzene/sulfonyl hydrazide, toluene/sulfonyl/ Sulfonyl hydrazide compounds such as hydrazide, p,p'-oxybis(benzenesulfonyl hydrazide), diphenylsulfonyl, 3'-disulfonyl hydrazide; calcium azide, 4,4'-diphenyl disulfonyl acid, Examples include azide compounds such as toluene and malhonyl acid.

Among them, nitroso compounds, azo compounds and azide compounds are preferably used. Such a blowing agent is usually 0.5 to 60 parts by weight, preferably 1 to 20 parts by weight, based on the total of 13,100 M parts of chloroprene rubber CA) and halogenated ethylene/α-olefin copolymer rubber CB). By blending, the apparent specific gravity is approximately 0.1 to 1.
．． 0 foam is produced. If necessary, a foaming aid may be used in combination with a foaming agent. A foaming aid is an additive that functions to lower the decomposition temperature of a foaming agent, promote decomposition, and make bubbles uniform. As blowing aids, mention may be made of organic acids such as salicylic acid, heptatalic acid, stearic acid; urea and its rust conductors.

A conventional process for producing a foam from conventional chloroprene rubber can be used to obtain a foam from the composition of the present invention.

The present invention described in detail above will be specifically explained below with reference to Examples.

Reference example 1゜Ethylene-propylene copolymer rubber [ethylene/propylene molar ratio 80/20, ML 1+ll (100c) 40
) 50r was dissolved in 2 tons of carbon tetrachloride, and the solution was charged into a 3-ton glass reactor equipped with a stirrer, a thermometer, and a chlorine gas inlet tube, and while maintaining the temperature at 6°C, the container was heated. At the same time, a 20F daylight color fluorescent light is irradiated from the outside and chlorine gas is injected into the reactor at 2.0? /rttm, and 5
The chlorination reaction was carried out for 0 minutes. Nitrogen gas was then passed through the reactor to remove excess chlorine gas.

Add 0.3 di-t-butylhydroxytoluene to this solution.
1 and 0.61 of calcium stearate were added.

Next, this was concentrated using an evaporator, and the solvent was thoroughly removed using a vacuum dryer at room temperature.

This chlorinated rubber substantially free of unsaturated bonds was heat-treated at 170C for 40 minutes in a constant temperature dryer under a nitrogen gas atmosphere.

The property values of this chlorinated rubber were measured as follows.

MLl-+-q(100C)=JIS K 6300
, Shimadzu MSV-200 model Mooney viscometer Chlorine content: Cylinder combustion method Gel fraction: Make a screen basket with 100 mesh wire mesh, and place about 0.2 tons of chlorinated rubber in it to the nearest 0.1 q. Weigh it and leave it in boiling #P-Xycin 600 for 1 hour. The insoluble matter remaining in the screen basket is dried under 50C1 vacuum for 6 hours, and after cooling to room temperature, it is reduced to 0.1 d unit. It was accurately weighed, and the proportion of insoluble matter was defined as the gel fraction.

Iodine value: First, chlorinated rubber was dissolved in carbon tetrachloride.

Then excess iodine monochloride Add acetic acid solution and store in a cool dark place for 60 minutes It was allowed to react for a while. After that, a large amount of Add potassium iodide solution and The released iodine is added to the starch solution. Sodium thiosulfate solution Titration was performed and the iodine value was calculated. Specific gravity: Toyo Seiki automatic hydrometer The measurement results are shown below.

Mooney viscosity 60 Chlorine content 25 wt Tigel fraction (1rnt Thiiodine value 6 Specific gravity 1.08 Reference example 2゜Ethylene-1-butene copolymer rubber [ethylene/1-butene molar ratio 92/8, ML1+11 (1000) 60]
was mechanically pulverized at room temperature using a Turbo Mill (manufactured by Turbo Kogyo). Copolymer rubber powder 2001, which passed through a 20-mesh wire mesh, and a nonionic surfactant [Product name Kopan 75]
A mixture of 0.11 (manufactured by Dai-Kogyo Seiyaku) and 2 tons of water was placed in a 6-ton glass reactor equipped with a stirrer and a thermometer, and heated to 80C. 2Q from the outside of the reaction vessel
While irradiating with an IF daylight fluorescent lamp, chlorine gas was added to the dispersion of the mixture at a concentration of 2.0? /min, and the chlorination reaction was continued for 70 minutes at a temperature of 80 to 86C. After the reaction, the solid part was taken out and washed 6 times for 1 hour using 2 tons of 60C warm water, and then washed once with cold water.
It was dried under reduced pressure at 0G.

This chlorinated copolymer rubber was heat-treated at 180C for 40 minutes in a dryer at room temperature under an atmosphere of drilling gas, and the properties of the heat-treated chlorinated rubber obtained were measured in the same manner as in Reference Example 1. The results are shown below.

Mooney viscosity 58 Chlorine content 20Wt Thigel fraction (i wt Thiiodine value 6 Specific gravity 1.02 Examples 1 to 6゜Chloroprene rubber Jf40 (Denki Kagaku Kogyo ML 1+
Il (100'C) 4 B, specific gravity 1.23), chlorinated ethylene propylene rubber (chlorine content 25 wt%)
, ML1+nC100'C) 60, specific gravity 1.08, iodine value 6) Rubber reinforcing agent and softener according to the compounding ratios in Tables 1 and 2, using a 4.37 Banbury mixer <OOC type manufactured by Kobe Steel, Ltd.) and kneaded for 6 minutes. The rubber temperature immediately after dumpout was 160C.

Continue using an 8 x 20 inch open roll.
A vulcanizing agent and a vulcanization accelerator were additionally mixed in the proportions shown in Table 1, and kneaded for 5 minutes at a roll temperature of 60 C to obtain a compounded rubber.

Place this compounded rubber in a hot press heated to 150C.
00 Ky/ci! The mixture was heated for 60 minutes under pressure to produce a vulcanized sheet, which was used as a sample for measurement.

The obtained vulcanized sheet was placed in a constant temperature room at 250 °C for 24 hours, and then subjected to a vulcanized rubber test, and the hardness (H8), tensile strength (TB Kq/cr71), and elongation (EB%) were determined according to JIS.
Measured based on K6301.

Next, the degree of swelling △V (%), which is an index of oil resistance, was determined based on the same (JIS K6601).The measurement conditions were JIS
It was immersed in No. I oil at 1ooC for 70 hours. next,
Similarly, the low temperature embrittlement temperature was determined based on JISK6601. Furthermore, a dynamic ozone resistance test was conducted. The measurement conditions were: ozone concentration 5 Qpplun, ambient temperature 40C1, elongation rate 5
The time until crack generation was investigated using the 0 cycle and the elongation cycle (S 0cpz).The results are shown in Table 2.

Table 1 1) Product name Denka Chloroprene #40 (411 manufactured by Ibi Gaku Kogyo Co., Ltd.) 2) t Geast S (manufactured by Tokai Carbon Co., Ltd.) 3
) #AH-16 (manufactured by Idemitsu Kosan Co., Ltd.) 11) Ethylene Thiourea (manufactured by Kawaguchi Kagaku Co., Ltd.) 5) Phenyl 1-naphthylamide (manufactured by Iriuchi Shinko Kagaku Co., Ltd.) Iodine value: First, chlorinated rubber was dissolved in carbon tetrachloride. . Next, an excess iodine monochloride/acetic acid solution was added, and the mixture was allowed to react in a cool, dark place for 60 minutes. Thereafter, a large excess of iodine solution was added, and the liberated iodine was titrated with a thiosulfuric acid solution using a starch solution as a coloring solution.

Comparative Example 1゜In Example 1, the rubber component was chloroprene rubber M40.
It was taken alone.

Comparative Example 2 In Example 1, the rubber component was chlorinated ethylene/α-olefin rubber alone.

Comparative Example 6゜In Example 1, the rubber component was chloroprene rubber, I/4
0.70 parts by weight and 60 parts by weight of ethylene/α-olefin copolymer rubber. The properties of the ethylene/α-olefin copolymer rubber are shown in Table 2.

The properties of the vulcanizates of Comparative Examples 1, 2 and B are shown in Table 2.

Claims (1)

[Claims] (1) Chloroprene rubber CA) and iodine value 6 to 20
Halogenated ethylene α-olefin copolymer rubber CB
) is A/B=9515 or A/B=20/
80. A vulcanizable rubber composition. The vulcanizable rubber composition according to item (1), wherein the halogen content of the (2,1 halogenated ethylene/α-olefin copolymer rubber CB) is 5 to 65% by weight. (3) Mooney viscosity of halogenated ethylene/α-olefin 7 co-M rubber (/J) [: ML 1. (100
C) ] is about 20 to about 150, the vulcanizable rubber composition according to item (1) or item (2). (4) The vulcanizable rubber composition according to any one of items (1) to (3), wherein the α-olefin contains 6 to 10 carbon atoms. (5) The vulcanizable rubber composition according to item (1), wherein the ethylene/α-olefin copolymer rubber before halogenation contains a polyene component having an iodine value of 6 to 30.