JP2000198901A - Acrylic rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition having improved handleability by including an acrylic polymer having an active halogen at a terminal of the main chain with a crosslinking agent. SOLUTION: This composition is obtained by compounding 100 pts.wt. acrylic polymer having at least one active halogen of the formula:-CH2C(R1)(R2)X at a terminal of the main chain, which is obtained by an atom transfer radical polymerization process in the presence of a catalyst being a complex of a metal selected from among copper, nickel, ruthenium, and iron and has a number- average molecular weight of 1,000-500,000, molecular weight distribution (weight- average molecular weight/number-average molecular weight ratio) of 1.8 or below, desirably, 1.7 or below, and an alkyl acrylate or alkoxyalkyl acrylate content of 50-100 wt.%, desirably, 70-100 wt.% with 0.01-10 pts.wt., desirably, 0.05-5 pts.wt. crosslinking agent selected from among aliphatic polyamines. In the formula, R1 and R2 are each a hydrogen atom or a monovalent organic group originated from the group bonded to the vinyl group of the vinyl monomer constituting the main chain; and X is chlorine, bromine, or iodine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an acrylic rubber composition. More specifically, the present invention relates to an acrylic rubber composition comprising an acrylic polymer having an active halogen as a crosslinkable group and a crosslinking agent.

[0002]

2. Description of the Related Art A halogen-containing acrylic rubber is synthesized by copolymerizing an alkyl acrylate and / or an alkoxyalkyl acrylate as a main component and an active halogen-containing monomer as a crosslinking component. The crosslinked product is used as a rubber having good oil resistance, heat resistance, weather resistance, ozone resistance and compression set, as a sealing material including a packing, a gasket, and various molded products.

[0003] Conventional halogen-containing acrylic rubbers are produced by so-called free radical polymerization such as bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, and bulk-suspension polymerization using a polymerization initiator. Since it is manufactured by a free radical polymerization method, the active halogen-containing monomer serving as a cross-linking point is almost randomly introduced into the molecular chain.
In order to obtain a rubber with low modulus and high elongation while securing a crosslinking point, it is inevitable to increase the molecular weight. Therefore, when adding various compounding materials to high-viscosity acrylic rubber because of its high molecular weight, it is inevitable to use an open roll or a kneader, etc., for compounding, and it cannot be said that handling is easy. . In fact, it is very difficult to improve the handling properties by lowering the viscosity by reducing the molecular weight.

[0004]

DISCLOSURE OF THE INVENTION In view of the above-mentioned situation, the present inventors have found that an acrylic polymer having an active halogen represented by the following general formula (1) at the terminal of the main chain is crosslinked with a crosslinking agent. As a result, the present inventors have found that an acrylic rubber composition having good handleability can be obtained, and arrived at the present invention.

[0005]

SUMMARY OF THE INVENTION Namely, the present invention provides the following two components; (A) an acrylic polymer having at least one active halogen in a main chain terminal represented by the general formula (1), -CH ₂ —C (R ¹ ) (R ² ) (X) (1) (wherein, R ¹ and R ² are the same or different and are derived from a group bonded to a vinyl group of a vinyl monomer constituting a main chain. It represents a hydrogen atom or a monovalent organic group, and X represents chlorine, bromine or iodine.) An acrylic rubber composition containing (B) a crosslinking agent.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the acrylic rubber composition of the present invention will be described in detail. [Acrylic Polymer of Component (A)] The acrylic polymer having at least one active halogen at the terminal of the main chain represented by the general formula (1) in the present invention is preferably prepared by an atom transfer radical polymerization method. It is obtained by (co) polymerizing at least one vinyl monomer such as alkyl acrylate and / or alkoxyalkyl acrylate. —CH ₂ —C (R ¹ ) (R ² ) (X) (1) (wherein R ¹ and R ² are the same or different and are bonded to a vinyl group of a vinyl monomer constituting a main chain) Represents a hydrogen atom or a monovalent organic group derived from X. X represents chlorine, bromine or iodine.)

The acrylic polymer having at least one active halogen at the terminal of the main chain represented by the general formula (1) is crosslinked by reacting with the crosslinking agent of the component (B).
It becomes a rubber-like cured product. If the average number of active halogens represented by the general formula (1) is less than one in one molecule, a sufficient cured product cannot be obtained. In order to obtain a sufficient cured product, the active halogen represented by the general formula (1) preferably has an average of 1.1 to 4 in one molecule, and preferably has an average of 1.2 to 2 in one molecule. More preferred.

The acrylic polymer as the component (A) may be a homopolymer or a copolymer.
In the case of a homopolymer, it is obtained by using one selected from alkyl acrylate and alkoxyalkyl acrylate. In the case of a copolymer, it is obtained by copolymerizing two or more selected from alkyl acrylate and alkoxyalkyl acrylate, or is selected from alkyl acrylate and alkoxyalkyl acrylate. It is obtained by copolymerizing at least one species with a monomer other than these.

In the present invention, the vinyl monomer constituting the main chain is a radically polymerizable monomer having an ethylenically unsaturated bond, including alkyl acrylate, alkoxyalkyl acrylate and other monomers. Examples of the alkyl acrylate in the present invention include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic acid-
t-butyl, acrylic acid-n-pentyl, acrylic acid-
n-hexyl, cyclohexyl acrylate, -n-heptyl acrylate, -n-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, and the like. Particularly, ethyl acrylate and n-butyl acrylate are preferred. These alkyl acrylates may be used alone or in combination of two or more.

Examples of the alkoxyalkyl acrylate include methoxymethyl acrylate, ethoxymethyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-propoxyethyl acrylate, acrylic acid -2-butoxyethyl, 3-methoxypropyl acrylate, (meth) acrylic acid-
Examples thereof include 4-methoxybutyl and the like, and particularly preferred are 2-methoxyethyl acrylate and 2-ethoxyethyl acrylate. These alkoxyalkyl acrylates may be used alone or in combination of two or more.

Further, vinyl monomers other than alkyl acrylates and alkoxyalkyl acrylates (hereinafter also referred to as "other monomers") include, for example, halogen-containing saturated carboxylic acids such as vinyl chloroacetate, allyl chloroacetate and the like. Alcohol esters; alkyl (meth) acrylate halides such as chloromethyl (meth) acrylate and 2-chloroethyl (meth) acrylate; unsaturated halogen-containing compounds such as chloromethyl vinyl ether and 3-chloropropyl allyl ether; Ethers; halogen-containing unsaturated ketones such as 2-chloroethyl vinyl ketone and 3-chloropropyl vinyl ketone; 2- (chloroacetoxy) ethyl (meth) acrylate, 3- (chloroacetoxy) acrylate ) (Meta) such as propyl
Halomethyloxy acrylates; halomethyl group-containing aromatic vinyl compounds such as p-chloromethylstyrene and p-chloromethyl α-methylstyrene; vinyl monomers having an active halogen capable of participating in a crosslinking reaction;
Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate , Cyclohexyl methacrylate, -n-heptyl methacrylate, -n-methacrylic acid
Alkyl methacrylates such as octyl, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate and stearyl methacrylate; phenyl (meth) acrylate, toluyl (meth) acrylate, and benzyl (meth) acrylate , 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid-
2-hydroxypropyl, glycidyl (meth) acrylate, 2-aminoethyl (meth) acrylate, γ- (methacryloyloxypropyl) trimethoxysilane, ethylene oxide adduct of (meth) acrylic acid, (meth)
Trifluoromethylmethyl acrylate, 2-trifluoromethylethyl (meth) acrylate, 2-perfluoroethylethyl (meth) acrylate, 2-perfluoroethyl-2- (meth) acrylate , 2-perfluoroethyl (meth) acrylate, perfluoromethyl (meth) acrylate, (meth)
Diperfluoromethylmethyl acrylate, 2-perfluoromethyl-2- (perfluoromethyl-2-methyl) acrylate, 2-perfluorohexylethyl (meth) acrylate, 2-perfluoro (meth) acrylate (Meth) acrylic acid monomers excluding alkyl acrylates such as decylethyl, (meth) acrylic acid-2-perfluorohexadecylethyl and (meth) acrylic acid, alkoxyalkyl acrylates and alkyl methacrylates; styrene, vinyltoluene Styrene monomers such as α-methylstyrene, chlorostyrene, styrenesulfonic acid and salts thereof; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; vinyltrimethoxysilane, vinyltriethoxysilane and the like Including silicon Vinyl monomers; maleic anhydride, maleic acid, monoalkyl and dialkyl esters of maleic acid; fumaric acid, monoalkyl and dialkyl esters of fumaric acid; maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide Octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide, and other maleimide monomers; acrylonitrile, methacrylonitrile, and other nitrile group-containing vinyl monomers; acrylamide, methacrylamide, and other amide group-containing vinyl monomers; vinyl acetate , Vinyl esters such as vinyl propionate, vinyl pivalate, vinyl benzoate and vinyl cinnamate; ethylene and propylene Alkenes; conjugated dienes such as butadiene and isoprene; vinyl chloride;
Examples thereof include vinylidene chloride, allyl chloride, and allyl alcohol. These may be used alone or 2
More than one species may be used in combination.

When the acrylic polymer of the above component (A) is obtained by copolymerizing an alkyl acrylate and / or an alkoxyalkyl acrylate with another monomer, the alkyl acrylate and the acrylic acid in the monomer mixture are used. The content of alkoxyalkyl is usually 50 to 100%, preferably 70 to 100%.
The content of other monomers is usually 0 to 50%. When a vinyl monomer having an active halogen is used, its content is usually 0 to 10%.

The number average molecular weight of the acrylic polymer (A) having at least one active halogen at the terminal of the main chain is not particularly limited, but is preferably in the range of 1,000 to 500,000. When the molecular weight is 1000 or less, it is difficult for the acrylic polymer to exhibit its original properties,
If it is more than 500,000, handling becomes difficult.

The molecular weight distribution of the acrylic polymer (A) having at least one active halogen at the terminal of the main chain, that is, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is particularly important. Not limited. However, it is preferable that the molecular weight distribution is narrow in order to keep the viscosity of the rubber composition before cross-linking low and to facilitate the handling, and to obtain sufficient cured physical properties. The value of the molecular weight distribution is preferably less than 1.8, more preferably 1.7 or less,
In addition, it is preferably 1.6 or less, more preferably 1.5 or less, particularly preferably 1.4 or less, and most preferably 1.3.
It is as follows. Most commonly, the molecular weight distribution is measured by gel permeation chromatography (GPC). Chloroform or THF is used as the mobile phase, and a polystyrene gel column is used as the column, and the number average molecular weight and the like can be determined by values in terms of polystyrene.

The "atom transfer radical polymerization method" is a method of polymerizing a vinyl monomer using an organic halide or a sulfonyl halide compound as an initiator, and using a transition metal complex as a catalyst. It is a radical polymerization which is difficult to control because a termination reaction due to coupling or the like is likely to occur, but a termination reaction hardly occurs and a polymer having a narrow molecular weight distribution (Mw / Mn is about 1.1 to 1.5) is obtained. In addition, the molecular weight can be freely controlled by the charging ratio of the monomer and the initiator. The polymerization terminal has an active halogen represented by the general formula (1).

The atom transfer radical polymerization method is described in, for example, Matyjaszewski et al., Journal of
American Chemical Society (J. Am. Che
m. Soc. 1995, 117, 5614, Macromolecules.
1995, 28, 7901, Science (Sci.
ence) 1996, 272, 866, WO96
/ 30421, WO97 / 18247, W
O98 / 01480, WO98 / 40415, or Sawamoto et al., Macromolecules 1995, 28.
Volume, page 1721.

Examples of the initiator in the "atom transfer radical polymerization method" include organic halides, especially organic halides having a highly reactive carbon-halogen bond, and sulfonyl halide compounds. Examples of the organic halide having a carbon-halogen bond having a particularly high reactivity include a carbonyl compound having a halogen at the α-position and a compound having a halogen at the benzyl position. These may be used alone or in combination of two or more.

The transition metal complex used as a catalyst in the above "atom transfer radical polymerization method" is not particularly limited.
For example, a complex having a central metal of Group 7, 8, 9, 9, or 11 of the periodic table can be used. Preferred examples include one or more selected from the group consisting of zero-valent copper, monovalent copper, divalent ruthenium, divalent iron, and divalent nickel complexes. Among them, a copper complex is more preferable. The above transition metal complexes may be used alone or in combination of two or more.

The monovalent copper compound is not particularly restricted but includes, for example, cuprous chloride, cuprous bromide, cuprous iodide,
Cuprous cyanide, cuprous oxide, cuprous perchlorate and the like can be mentioned. When a copper compound is used, 2,2′-bipyridyl and its derivatives, 1,2
A ligand such as 10-phenanthroline and a derivative thereof, a polyamine such as tetramethylethylenediamine, pentamethyldiethylenetriamine, and hexamethyltris (2-aminoethyl) amine can be added.

In addition, tristridium divalent ruthenium chloride
Phenylphosphine complex (RuCl_Two(PPh_Three )_Three )
Are also suitable as catalysts. Ruthenium compound as catalyst
If used, aluminum alkoxy
Sides can be added. Furthermore, divalent iron screws
Triphenylphosphine complex (FeCl_Two (PPh_Three )
_Two ) Bistriphenylphosphine complex of divalent nickel
Body (NiCl_Two (PPh _Three )_Two ) And divalent nickel
Bistributylphosphine complex (NiBr_Two(PB
u_Three )_Two ) Are also suitable as catalysts.

The above polymerization reaction can be carried out without a solvent or in various solvents. The solvent is not particularly limited and includes, for example, hydrocarbon solvents such as benzene and toluene;
Ether solvents such as diethyl ether and tetrahydrofuran; halogenated hydrocarbon solvents such as methylene chloride and chloroform; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; methanol, ethanol, propanol, isopropanol, n-butyl alcohol, tert Alcohol solvents such as -butyl alcohol; nitrile solvents such as acetonitrile, propionitrile and benzonitrile; ester solvents such as ethyl acetate and butyl acetate; carbonate solvents such as ethylene carbonate and propylene carbonate. . These may be used alone or in combination of two or more. The above "atom transfer radical polymerization method"
Can be performed in the range of 0 to 200 ° C. Preferably, it is in the range of room temperature to 150 ° C.

In order to obtain an acrylic polymer having at least one active halogen at the end of the molecular chain by using the "atom transfer radical polymerization method", an organic halide having two or more starting points is used as an initiator. Alternatively, a sulfonyl halide compound or the like is preferably used. The organic halide or the sulfonyl halide compound having two or more starting points is not particularly limited, and examples thereof include the following compounds.

Specific examples thereof include o-, m-, p-XCH_Two -C₆ H_Four -CH_Two X, o
-, M-, p-CH_Three C (H) (X) -C₆ H_Four -C
(H) (X) CH_Three , O-, m-, p- (CH_Three )_TwoC
(X) -C₆ H_Four -C (X) (CH_Three )_Two (However, in the above formula, C₆ H_Four Represents a phenylene group.
X represents chlorine, bromine, or iodine) RO_Two CC (H) (X)-(CH_Two )_n -C (H)
(X) -CO_Two R, RO_TwoCC (CH_Three ) (X)-
(CH_Two )_n -C (CH_Three ) (X) -CO_Two R, RC
(O) -C (H) (X)-(CH_Two )_n -C (H)
(X) -C (O) R, RC (O) -C (CH_Three ) (X)
− (CH_Two )_n -C (CH_Three ) (X) —C (O) R (wherein R is an alkyl group having 1 to 20 carbon atoms, aryl)
Or an aralkyl group. n is an integer from 0 to 20
X represents chlorine, bromine or iodine.) XCH_Two -C (O) -CH_Two X, H_Three CC (H)
(X) -C (O) -C (H) (X) -CH_Three , (H_Three 
C)_Two C (X) -C (O) -C (X) (CH_Three )_Two , C
₆ H_Five C (H) (X)-(CH_Two )_n -C (H) (X)
C₆ H_Five (In the above formula, X represents chlorine, bromine or iodine, and n is
XCH represents an integer of 0 to 20) XCH_Two CO_Two − (CH_Two )_n -OCOCH_Two X, CH
_Three C (H) (X) CO_Two− (CH_Two )_n -OCOC
(H) (X) CH_Three , (CH_Three )_Two C (X) CO_Two −
(CH_Two )_n -OCOC (X) (CH_Three )_Two In the above formula, n represents an integer of 1 to 20. XCH_Two C (O) C (O) CH_Two X, CH_Three C (H)
(X) C (O) C (O) C (H) (X) CH_Three , (CH
_Three )_Two C (X) C (O) C (O) C (X) (CH_Three)
_Two , O-, m-, p-XCH_Two CO_Two -C₆ H_Four -OC
OCH_Two X, o-, m-, p-CH_Three C (H) (X) C
O_Two -C₆ H_Four -OCOC (H) (X) CH_Three, O-,
m-, p- (CH_Three )_Two C (X) CO_Two -C₆ H_Four -O
COC (X) (CH_Three )_Two , O-, m-, p-XSO_Two 
-C₆ H_Four -SO_Two X In the above formula, X represents chlorine, bromine, or iodine. Is raised
I can do it. These may be used alone or in combination of two or more.
May be.

[Crosslinking Agent of Component (B)] The crosslinking agent of component (B) (also referred to as “vulcanizing agent”) used in the present invention is as follows.
At least one active halogen which is a crosslinkable group is added to the terminal of the main chain.
It reacts with the active halogen atom of the acrylic polymer to have a bond between the above-mentioned acrylic polymer molecules, and a crosslinking agent usually used for halogen-containing acrylic rubber can be used.

Examples of such a crosslinking agent include aliphatic polyamines such as ethylenediamine monohydrate, trimene base, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and hexamethylenediamine; and the above-mentioned fatty acids such as hexamethylenediaminecarbamate. Carbamates of group III polyamines; metal salts of fatty acids such as sodium laurate, potassium laurate, sodium stearate and potassium stearate; and ammonium salts of organic carboxylic acids such as ammonium benzoate, but are not limited thereto. Among them, aliphatic polyamines or carbamates of aliphatic polyamines are preferred.

The amount of the crosslinking agent (B) is usually
It is 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the acrylic polymer as the component (A). If the amount is less than 0.01 part by weight, the crosslinking speed and the degree of crosslinking may decrease. If the amount exceeds 10 parts by weight, the crosslinking density may become too high.

[0027] In addition to these crosslinking agents, a sulfur accelerator used in halogen-containing acrylic rubbers can be blended. Examples of such a vulcanization accelerator include dibasic phosphates such as dibasic lead phosphate; thioureas such as diethylthiourea and diphenylthiourea; dipentamethylenethiuram tetrasulfide and tetramethylthiuram disulfide. , Thiuram sulfides such as tetrabutylthiuram disulfide; dithiocarbamate salts such as zinc dimethyldithiocarbamate, zinc dibutyldithiocarbamate, and copper dimethyldithiocarbamate;
Examples include sulfur, but are not limited thereto.

The combination of the crosslinking agent and the vulcanization accelerator is not particularly limited, but a combination of a carbamate of an aliphatic polyamine and a dibasic phosphate, a combination of a fatty acid metal salt and a thiuram sulfide, or a combination of a fatty acid metal salt and sulfur is preferred. .

The acrylic rubber composition of the present invention can be used with the acrylic polymer (A) and the crosslinking agent (B) especially when the acrylic polymer (A) having an active halogen at the main chain terminal has a plurality of active halogens. ) May be used, or may be a composition further blended with a conventional halogen-containing acrylic rubber obtained by copolymerizing an active halogen-containing monomer. The amount added at this time is not particularly limited.
0 parts by weight, preferably 1 to 5000 parts by weight, more preferably 10 to 1000 parts by weight.

The acrylic rubber composition of the present invention may contain a filler, a plasticizer, an antioxidant, an ultraviolet absorber, a light stabilizer, if necessary, for the purpose of adjusting various properties of the rubber composition or the crosslinked product. Agents, scorch inhibitors, crosslinking retarders, processing aids, lubricants, adhesives, lubricants, flame retardants, anti-dripping agents, fungicides, antistatic agents, coloring agents, adhesion promoters, weatherability improvers, You may mix | blend a mechanical property modifier and the like. Further, other rubbers, elastomers or resins can be blended as long as the properties of the acrylic rubber composition are not impaired.

The filler is not particularly restricted but includes, for example, reinforcing fillers such as fumed silica, precipitated silica, silicic anhydride, hydrous silicic acid and carbon black; calcium carbonate, magnesium carbonate, diatomaceous earth,
Fillers such as calcined clay, clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, zinc oxide, activated zinc white and shirasu balloon;
Fibrous fillers such as glass fibers and filaments are included. In order to obtain a high-strength cured product with these fillers, fumed silica, precipitated silica, silicic anhydride, hydrous silicic acid, carbon black, surface-treated fine calcium carbonate, calcined clay, clay and activated zinc are mainly used. A filler selected from flowers and the like can be added. When it is desired to obtain a cured product having low strength and large elongation, a filler selected mainly from titanium oxide, calcium carbonate, talc, ferric oxide, zinc oxide, shirasu balloon and the like can be added. These may be used alone or in combination of two or more.

Examples of other rubbers and elastomers include olefin elastomers, styrene elastomers, vinyl chloride elastomers, polyester elastomers, polyamide elastomers, polyurethane elastomers, polysiloxane elastomers, fluorine elastomers, natural rubbers, Examples include, but are not limited to, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and chloroprene rubber. These may be used alone or in combination of two or more.

The conditions for curing the acrylic rubber composition of the present invention are such that the heating temperature is usually 150 ° C. or higher, preferably 150 to 200 ° C. The heating method is not particularly limited, and methods such as press heating, steam heating, oven heating, and hot air heating are possible. Further, post-crosslinking by post-heating may be performed.

The acrylic rubber composition of the present invention can be used in a wide range of fields such as transportation machines such as automobiles, general equipment, devices, electricity, electronics and construction, in addition to sealing materials such as O-rings, oil seals and bearing seals. It is useful as cushioning material, protective material, wire covering material, industrial belts, hoses and sheets.

[0035]

EXAMPLES The present invention will be described below with reference to examples.
It is not limited to the following embodiment. In the following Examples and Comparative Examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively. In the following examples, "number average molecular weight"
And "molecular weight distribution (ratio of weight average molecular weight to number average molecular weight)" was calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC). However, a GPC column filled with a polystyrene crosslinked gel and chloroform as a GPC solvent were used.

(Production Example 1) Poly (acrylic acid ester) having bromine groups at both ends
Synthesis Example of Polymer CuBr (36.0 g, 0.251 mol) was charged into a 10-L separable flask equipped with a reflux tube and a stirrer, and the inside of the reaction vessel was purged with nitrogen. Acetonitrile (61
8 mL) and stirred for 15 minutes at 70 ° C. in an oil bath. To this, butyl acrylate (0.322 kg, 2.5
1 mol), ethyl acrylate (0.463 kg, 4.
62 mol), 2-methoxyethyl acrylate (0.3
79 kg, 2.91 mol), diethyl 2,5-dibromoadipate (151 g, 0.419 mol), pentamethyldiethylenetriamine (2.18 mL, 1.81)
g, 0.0105 mol) (hereinafter triamine) was added to start the reaction. While heating and stirring at 70 ° C., butyl acrylate (1.29 kg, 10.0 mol
l), ethyl acrylate (1.85 kg, 18.5 mol)
l), 2-methoxyethyl acrylate (1.52 kg,
(11.7 mol) was continuously dropped over 210 minutes.
During the dropping of the monomer, triamine (7.63 mL, 6.
(35 g, 0.0366 mol). The reaction was terminated 270 minutes after the start of the reaction. The reaction mixture was diluted with toluene and passed through an activated alumina column to remove the polymerization catalyst. Toluene is distilled off, and poly (butyl acrylate) having bromine groups at both ends (polymer [1])
I got The number average molecular weight of the obtained polymer is 18185,
The molecular weight distribution was 1.13.

Example 1 100 parts of commercially available active chlorine-based vulcanized acrylic rubber (unvulcanized product; number average molecular weight 290000, molecular weight distribution 3.3, chlorine content 0.36%), Production Example 1
Was dissolved in toluene (500 mL), and the toluene was distilled off to obtain a uniform resin. 100 parts of the obtained resin, 1.0 part of sodium stearate, and 0.6 part of sulfur were mixed well with a kneader. Compared with Comparative Example 1, the viscosity of the resin was lower. The mixture was heated at 170 ° C. for 30 minutes using a press molding machine to perform primary vulcanization. The sheet was further heated at 180 ° C. for 2 hours and subjected to secondary vulcanization to obtain a sheet-like cured product having rubber elasticity. The cured product obtained in Comparative Example 1 showed higher elongation.

(Comparative Example 1) 100 parts of the commercially available active chlorine-based vulcanized acrylic rubber used in Example 1, 1.0 part of sodium stearate, and 0.6 part of sulfur were thoroughly mixed in a kneader.
The mixture was heated at 170 ° C. for 30 minutes using a press molding machine to perform primary vulcanization. The sheet was further heated at 180 ° C. for 2 hours and subjected to secondary vulcanization to obtain a cured sheet having rubber elasticity.

(Example 2) 100 parts of the commercially available active chlorine-based vulcanized acrylic rubber used in Example 1 and 30 parts of the polymer obtained in Production Example 1 were heated to 150 ° C by a kneader, Kneaded. A composition was obtained by kneading 100 parts of the resin obtained by kneading and 1 part of triethylenetetramine at room temperature. The composition was press-molded at 180 ° C. for 10 minutes, and further heated at 180 ° C. for 1 hour to obtain a sheet-like cured product. A No. 2 (1/3) type dumbbell test piece was punched from the sheet-shaped cured product, and a tensile test was performed using an autograph manufactured by Shimadzu (measurement conditions: 23 ° C., 200 mm / mi).
n). The breaking strength was 1.6 MPa and the breaking elongation was 82%. Workability was improved as compared with Comparative Example 2, and a uniform sheet was obtained. Further, the strength of the cured product was also increased.

(Comparative Example 2) 100 parts of the commercially available active chlorine-based vulcanized acrylic rubber used in Example 1 and 1.0 part of triethylenetetramine were thoroughly mixed in a kneader to obtain a composition.
Press molding at 180 ° C for 10 minutes,
Heated for an hour, but cured during insufficient melting. A No. 2 (1/3) dumbbell test piece was punched out of the obtained sheet-shaped cured product, and a tensile test was performed using an autograph manufactured by Shimadzu (measurement conditions: 23 ° C., 200 mm / mi).
n). The breaking strength was 1.1 MPa and the breaking elongation was 92%.

[0041]

As described above, the acrylic rubber composition of the present invention has the above-mentioned constitution, so that it can provide a crosslinked body having good handleability and good characteristics.

Claims (7)

[Claims] (A) an acrylic polymer having at least one active halogen represented by the general formula (1) at an end of a main chain, —CH ₂ —C (R ¹ ) (R ² (X) (1) (In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom or a monovalent organic group derived from a group bonded to a vinyl group of a vinyl monomer constituting a main chain.) X represents chlorine, bromine or iodine.) (B) An acrylic rubber composition comprising (B) a crosslinking agent. 2. The acrylic rubber composition according to claim 1, wherein the molecular weight distribution of the acrylic polymer (A) is less than 1.8. 3. The acrylic rubber composition according to claim 1, wherein the method for producing the acrylic polymer as the component (A) is an atom transfer radical polymerization method. 4. A catalyst for the atom transfer radical polymerization method, wherein copper,
The acrylic rubber composition according to claim 3, which is a complex of a metal selected from the group consisting of nickel, ruthenium, and iron. 5. The acrylic rubber composition according to claim 4, wherein the catalyst for the atom transfer radical polymerization method is a copper complex. 6. The acrylic rubber composition according to claim 1, wherein the crosslinking agent as the component (B) is an aliphatic polyamine. 7. The acrylic rubber composition according to claim 1, wherein the crosslinking agent (B) is an aliphatic polyamine carbamate.