KR20090039036A - Rubber modifier and modified acrylonitrile-butadiene rubber - Google Patents

Abstract

A rubber modifier is provided to improve heat resistance and mechanical property while not degrading oil resistance of acrylonitrile butadiene rubber. A rubber modifier has a core-shell structure containing a crosslinking reaction site. The core is a polymer which is formed by polymerizing a monomer mixture consisting of an acrylic monomer, hydrophilic monomer and crosslinkable monomer having the crosslinking reaction site and is included in the amount of 50-95 weight% based on the total content of core-shell latex. The shell is a methacrylic polymer and is included in the amount of 5-50 weight% based on the total content of core-shell latex.

Description

Rubber Modifier and Modified Acrylonitrile-Butadiene Rubber

The present invention relates to a rubber modifier and a modified acrylonitrile-butadiene-based rubber (NBR) including the same, more specifically, heat resistance and mechanical properties without lowering the oil resistance of the acrylonitrile-butadiene-based rubber (NBR) It relates to a rubber modifier that can improve the back and the like and modified acrylonitrile-butadiene-based rubber (NBR) including the same.

Recently, as the domestic and overseas automobile and machinery industries have developed rapidly, the demand for rubber products that require oil resistance is continuously increasing. Currently, most commonly used oil-resistant rubbers include acrylonitrile butadiene rubber (NBR), epichlorohydrin rubber (ECO), and chlorinated rubber (CR).

The NBR is prepared by copolymerizing acrylonitrile and butadiene by batch or continuous low temperature emulsion polymerization, having a strong nitrile group and having a solubility parameter of 9 or more, which is resistant to petroleum solvents and is the most representative oil-resistant rubber. It is said to be excellent in compatibility with vinyl chloride resin, nitrocellulose, phenol resin and the like.

In addition, NBR is not only excellent in oil resistance than natural rubber and styrene-butadiene rubber (SBR), but also has good abrasion resistance and aging resistance, low gas permeability, and strong cohesion.

Therefore, the NBR is widely used in oil-resistant hoses, belts, rollers, tank linings, adhesives, shoe soles, tubes, sealers, packing agents, and the like.

However, NBR has a limit on its use temperature (about 80 ℃) because of its low heat resistance (Korea Patent Publication: 2004-0057839), so the parts that require both oil resistance and heat resistance are ACM (acrylic rubber), EAM (ethylene acrylic rubber), FKM (fluroelastomer) is used, ACM (acrylic rubber) has a problem that requires a lot of cross-linking energy and cross-linking time in the manufacturing (US Patent Publication: 2005-0250913), EAM (ethylene acrylic rubber) lacks oil resistance And, FKM (fluroelastomer) has a problem that the price is expensive.

As a method for improving the heat resistance of the NBR, a method of producing HNBR by hydrogenating the NBR has been disclosed. However, since it requires a lot of cost during manufacture, it has to be blended with other low-cost resins to meet the product cost. (US Patent Publication: 2006-0270783, Korean Patent Publication: 2005-0112751).

Therefore, it is urgent to develop NBR which is excellent in both oil resistance and heat resistance.

In order to solve the problems of the prior art as described above, the present invention is a rubber modifier that can improve the heat resistance and mechanical properties, etc. without reducing the oil resistance of acrylonitrile-butadiene-based rubber (NBR) and modified acrylic including the same It is an object to provide a ronitrile-butadiene rubber (NBR).

It is another object of the present invention to provide a method for producing the modified acrylonitrile-butadiene rubber (NBR).

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention has a core-shell structure having a crosslinking reaction site, the core is polymerized a monomer mixture comprising an acrylic monomer, a hydrophilic monomer and a crosslinkable monomer having a crosslinking reaction site 50 to 95% by weight, based on the total content of the core-shell latex as the polymer formed, wherein the shell is a methacryl-based polymer including 5 to 50% by weight based on the total content of the core-shell latex, and the like. Modified acrylonitrile-butadiene based rubber (NBR) is provided.

The present invention also provides a method for producing the modified acrylonitrile-butadiene rubber (NBR).

As described above, according to the present invention, a rubber modifier capable of improving heat resistance and mechanical properties without reducing oil resistance of acrylonitrile-butadiene-based rubber (NBR) and a modified acrylonitrile-butadiene including the same It is effective to provide a system rubber (NBR) or the like.

Hereinafter, the present invention will be described in detail.

The inventors have found that when the acrylonitrile-butadiene rubber (NBR) is modified with a core-shell structured acrylic rubber modifier having a crosslinking reaction site, the heat resistance and mechanical properties are improved without oil resistance being lowered. On the basis of this, the present invention has been completed.

The rubber modifier of the present invention has a core-shell structure having a crosslinking reaction site, and the core is a polymer formed by polymerizing a monomer mixture comprising an acrylic monomer, a hydrophilic monomer and a crosslinking monomer having a crosslinking reaction site. The shell latex is included in an amount of 50 to 95% by weight, and the shell is a methacrylic polymer, characterized in that it is included in an amount of 5 to 50% by weight, based on the total content of core-shell latex.

The rubber modifier is a material used to modify the properties of the rubber, particularly preferably used as a rubber modifier to improve the oil resistance, heat resistance and mechanical properties of the acrylonitrile-butadiene-based rubber (NBR).

The acrylic monomer is not particularly limited as long as it has 5 to 20 carbon atoms.

Preferably, the acrylic monomer is included in an amount of 45 to 99 parts by weight based on 100 parts by weight of the core. Within this range, the rubber modifier has an effect of improving heat resistance and mechanical properties while maintaining oil resistance of the rubber to be modified. .

The hydrophilic monomer is 1 selected from the group consisting of 2-methoxyethyl (meth) acrylate, (meth) acrylic acid, hydroxylethyl (meth) acrylate, acrylonitrile, itaconic acid and maleic acid. It is preferable that it is a species or more.

Preferably, the hydrophilic monomer is included in an amount of 0.5 to 50 parts by weight based on 100 parts by weight of the core. Within this range, the rubber modifier has an effect of improving oil resistance while maintaining heat resistance and mechanical properties of the rubber to be modified. .

The crosslinking reaction site refers to a site capable of causing a crosslinking reaction with the rubber to be modified, and does not participate in the polymerization reaction when preparing the rubber modifier.

The crosslinkable monomer is a group consisting of allyl (meth) acrylate, cyclopentyl (meth) acrylate, norbornene (meth) acrylate, glycidyl (meth) acrylate, vinyl chloroacetate and 2-chloroethylvinyl ether It is preferable that it is at least 1 sort (s) selected from.

Preferably, the crosslinkable monomer includes 0.5 to 5 parts by weight based on 100 parts by weight of the core. Within this range, the rubber modifier has an effect of improving oil resistance and heat resistance of the rubber to be modified.

The core is preferably from 50 to 95% by weight based on the total content of the core-shell latex, within this range the rubber modifier is excellent in the cohesive properties, there is an effect to improve the physical properties of the rubber to be modified.

The shell is not particularly limited as long as it is a methacrylic polymer prepared from a methacrylic monomer having 5 to 10 carbon atoms, but 5 to 99 parts by weight of the methacrylic monomer, 0.5 to 90 parts by weight of the acrylic monomer, and 100 parts by weight of the total cell; It is preferable that it is a methacryl-type polymer superposed | polymerized from 0.5-5 weight part of crosslinkable monomers which have a crosslinking reaction site.

The shell is preferably 5 to 50% by weight based on the total content of the core-shell latex, within this range the rubber modifier is excellent in the cohesive properties, there is an effect to improve the physical properties of the rubber to be modified.

The modified acrylonitrile-butadiene rubber of the present invention is characterized in that the rubber modifier and acrylonitrile-butadiene rubber (NBR) are crosslinked.

The acrylonitrile-butadiene rubber (NBR) has a weight average molecular weight of 200,000 to 2000,000, an acrylonitrile content of 20 to 50% by weight, and preferably a gel content of 5% by weight or less, within this range. Has the effect of expressing the mechanical properties and oil resistance peculiar to NBR.

The modifier preferably has a weight average molecular weight of 500,000 to 3000,000 and a gel content of 5% by weight or less. Within this range, the modifier has an effect of exhibiting excellent processability, moldability, mechanical properties, heat resistance and oil resistance. have.

The crosslinking method is not particularly limited, but after blending, flocculating and drying the modifier and acrylonitrile-butadiene rubber (NBR), carbon black, anti-aging agent, zinc oxide (ZnO), stearic acid, metal soap ), A vulcanization activator and sulfur are preferably kneaded.

The carbon black serves to improve mechanical properties such as wear resistance and tensile strength as a rubber filler reinforcement.

The anti-oxidant is deteriorated to prevent the aging of the double bonds present in the butadiene-based rubber, but is generally limited if used for kneading of the rubber, it is preferable to use an amine-based or phenol-based antioxidant.

The zinc oxide (ZnO) forms a complex during processing with stearic acid to serve as a vulcanization promoter.

The stearic acid not only facilitates rubber processing as a processing aid, but also forms a complex with zinc oxide (ZnO) to serve as a vulcanization promoter.

The metal soap serves as a processing aid and a vulcanization accelerator, and is mainly used in acrylic rubber processing. As a specific example, sodium stearate, potassium stearate, and the like may be used.

The vulcanization activator (activator) is a vulcanization reaction occurs uniformly in the rubber reaction site, and serves to improve the vulcanization efficiency and reaction speed, specific examples of thiazole (thiazole), thiuram (thiuram), It may be at least one selected from the group consisting of thiourea-based, guanine-based and thiocarbamate-based activators.

Sulfur is used as a rubber crosslinking agent, in addition to peroxide, but generally sulfur crosslinking system is widely used.

The rubber modifier is 0.5 to 99.5 parts by weight, and the acrylonitrile-butadiene rubber (NBR) is preferably 0.5 to 99.5 parts by weight.

The rubber modifier is preferably prepared by emulsion polymerization.

By adjusting the composition, morphology, gel content, molecular weight and the like of the rubber modifier, acrylonitrile-butadiene-based rubber (NBR) has the effect of improving heat resistance and mechanical properties without deteriorating oil resistance.

Method for producing a modified acrylonitrile-butadiene-based rubber of the present invention comprises the steps of blending, agglomeration and drying the rubber modifier and acrylonitrile-butadiene-based rubber (NBR) to prepare an acrylonitrile-butadiene-based rubber composition; And prescribing and kneading the rubber composition with carbon black, an antioxidant, zinc oxide (ZnO), stearic acid, metal soap, a vulcanization activator, and sulfur.

The rubber modifier is 0.5 to 99.5 parts by weight, and the acrylonitrile-butadiene rubber (NBR) is preferably 0.5 to 99.5 parts by weight.

The rubber modifier preferably has a weight average molecular weight of 500,000 to 3000,000 and a gel content of 5% by weight or less. The acrylonitrile-butadiene-based rubber (NBR) modified within this range has excellent processability or formability. It works.

The acrylonitrile-butadiene rubber (NBR) has a weight average molecular weight of 200,000 to 2000,000, an acrylonitrile content of 20 to 50% by weight, and preferably a gel content of 5% by weight or less, within this range. Acrylonitrile-butadiene-based rubber (NBR) modified at has an effect of having excellent processability or formability.

The anti-aging agent is a thermal degradation to prevent the aging of the double bonds present in the butadiene-based rubber, but is not usually limited as long as it is used in rubber kneading, it is preferable to use an amine-based or phenol-based antioxidant.

The vulcanization activator (activator) is a vulcanization reaction occurs uniformly in the rubber reaction site, and serves to improve the vulcanization efficiency and reaction speed, specific examples of thiazole (thiazole), thiuram (thiuram), It may be at least one selected from the group consisting of thiourea-based, guanine-based and thiocarbamate-based active agents.

Hereinafter, preferred examples are provided to help the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and various changes and modifications within the scope and spirit of the present invention are apparent to those skilled in the art. It is natural that such variations and modifications fall within the scope of the appended claims.

EXAMPLE

Example  One

<Core Polymerization>

A four-necked flask reactor equipped with a stirrer, a thermometer, a nitrogen inlet, and a circulation condenser was prepared, where 80 parts by weight of deionized water (DDI water), 0.15 parts by weight of NaHCO ₃ , and 0.02 parts of ferrous sulfate were added. Parts by weight, and 0.27 parts by weight of disodium ethylenediaminetetraacetate were added thereto, and the inside temperature of the reactor was raised to 35 ° C. under a nitrogen atmosphere. 40 parts by weight of deionized water, 0.40 parts by weight of sodium dodecylbenzenesulfonate (SDBS), 58.0 parts by weight of ethyl acrylate (EA), 2-methoxyethylacrylic acid when the temperature inside the reactor reached 35 ° C Monomer preemulsion consisting of 20 parts by weight of 2-methoxyethylacrylate (MEA) and 2 parts by weight of 2-chloroethylvinylether (CEV) and 0.12 parts by weight of an initiator paramentane peroxide, an activator 0.3 parts by weight of formaldehyde sodium sulfoxylate was added simultaneously at 35 ° C. for 7 hours to proceed with the reaction. After adding all of the monomer preemulsion, 0.05 parts by weight of paramentane peroxide and 0.05 parts by weight of formaldehyde sodium sulfoxylate were further added and aged for 1 hour to prepare a rubbery core latex.

The rubber core latex prepared had a polymerization conversion of 99%, an average particle diameter of 150 nm, and a total solid content (TSC) of 39% by weight.

<Cell polymerization>

The reactor containing the prepared rubbery latex was maintained at 45 ° C., 15 parts by weight of ion-exchanged water, 0.15 parts by weight of sodium dodecylbenzenesulfonate, 14.5 parts by weight of methylmethacrylate (MMA), ethyl A monomer preemulsion consisting of 5 parts by weight of acrylate and 0.5 parts by weight of 2-chloroethyl vinyl ether, 0.05 part by weight of an initiator paramentan peroxide, and 0.10 part by weight of an active formaldehyde sodium sulfoxylate for 2 hours The reaction was advanced. After all the monomer preemulsion was added, 0.015 parts by weight of paramentane peroxide and 0.03 parts by weight of formaldehyde sodium sulfoxylate were further added and aged for 1 hour to prepare a final core-shell latex.

The prepared core-shell latex (E1) had an average particle diameter of 160 nm and a total solid content of 40 wt%.

Example  2

40 weight part of deionized water, 0.40 weight part of sodium dodecylbenzenesulfonate (SDBS), 38.0 weight part of ethyl acrylates (ethylacrylate; EA), butyl acrylate (BA) when manufacturing a core in Example 1 20 parts by weight, 2-methoxyethylacrylate (MEA) 20 parts by weight and 2-chloroethylvinyl ether (CEV) 2 parts by weight of the monomer pre-emulsion was prepared except It carried out in the same manner as in Example 1.

Example  3

40 weight part of deionized water, 0.40 weight part of sodium dodecylbenzenesulfonate (SDBS), 58 weight part of butyl acrylates (butylacrylate; BA) at the time of manufacturing a core in Example 1, and 2-methoxyethyl acrylate ( 20 parts by weight of 2-methoxyethylacrylate (MEA) and 2 parts by weight of 2-chloroethylvinylether (CEV) were added, except that a monomer preemulsion was prepared in the same manner as in Example 1.

Comparative example  One

<Above Example  Preparation of Copolymer Having the Same Composition as 1, but Having No Core-Shell Structure>

A four-necked flask reactor equipped with a stirrer, a thermometer, a nitrogen inlet, and a circulation condenser was prepared, including 80 parts by weight of deionized water (DDI water), 0.15 parts by weight of NaHCO ₃ , and 0.02 parts of ferrous sulfate. Parts by weight, and 0.27 parts by weight of disodium ethylenediaminetetraacetate were added thereto, and the inside temperature of the reactor was raised to 35 ° C. under a nitrogen atmosphere. 55 parts by weight of deionized water, 0.55 parts by weight of sodium dodecylbenzenesulfonate (SDBS), 63.0 parts by weight of ethyl acrylate (EA), methylmethacrylate when the internal temperature of the reactor reached 35 ℃ MMA) 14.5 parts by weight, monomer preemulsion consisting of 20 parts by weight of 2-methoxyethylacrylate (MEA) and 2.5 parts by weight of 2-chloroethylvinylether (CEV) and initiator paramen 0.17 parts by weight of tantalum peroxide (paramenthane peroxide), 0.40 parts by weight of formaldehyde sodium sulfoxylate (activator) was added to the reaction at the same time for 9 hours. After adding all of the monomer preemulsion, 0.05 parts by weight of paramentane peroxide and 0.05 parts by weight of formaldehyde sodium sulfoxylate were further added and aged for 1 hour to prepare a copolymer latex (C1) having no core-shell structure. .

The prepared copolymer latex (C1) had a polymerization conversion of 99%, an average particle diameter of 160 nm, and a total solid content (TSC) of 39 wt%.

Comparative example  2

40 weight part of deionized water, 0.40 weight part of sodium dodecylbenzenesulfonate (DBS), 78.0 weight part of ethylacrylates (EA), and 2-chloroethyl vinyl ether (2) -Chloroethylvinylether: CEV) 2 parts by weight was prepared in the same manner as in Example 1, except that the monomer preemulsion was prepared.

Comparative example  3

40 weight part of deionized water, 0.40 part by weight of sodium dodecylbenzenesulfonate (SDBS), 60.0 part by weight of ethyl acrylate (ethylacrylate; EA) and 2-methoxyethyl acrylate when preparing the core in Example 1 20 parts by weight of 2-methoxyethylacrylate (MEA) was prepared in the same manner as in Example 1 except that a monomer preemulsion was prepared and 15.0 parts by weight of methylmethacrylate (MMA) was used for cell polymerization.

The weight average molecular weight and gel content of the polymers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1 together with the composition and content of the monomers used in the polymerization.

Furtherance Example 1 (E1) Example 2 (E2) Example 3 (E3) Comparative Example 1 (C1) Comparative Example 2 (C2) Comparative Example 3 (C3) core EA 58 38 63 78 60 BA 20 58 MEA 20 20 20 20 20 CEV 2 2 2 2.5 2 Cell MMA 14.5 14.5 14.5 14.5 14.5 15 EA 5 5 5 5 5 CEV 0.5 0.5 0.5 0.5 Weight average molecular weight (g / mol) 850,000 950,000 900,000 102 million 990,000 870,000 Gel content 0.5% or less

Example  4 to 8

The core-shell latexes (E1 to E3) and NBR latex (TSC 25%, AN content 42%) prepared in Examples 1 to 3 were blended to the contents shown in Table 2 below, and ion-exchanged water was added to the latex mixture. The solids content was lowered to 10% by weight. Thereafter, the latex mixture was heated to 35 ° C., and a 2 wt% MgSO ₄ aqueous solution was added thereto while stirring to prepare a coagulation slurry by coagulating the polymer particles.

The flocculation slurry was heated to 70 ° C., aged for 20 minutes and then cooled. This was washed 2-3 times with ion-exchanged water to remove residual monomer, and then dehydrated using a filter to prepare a rubber crumb.

The rubber crumb was dried at 100 ° C. for 2 hours using a hot air dryer to prepare a dry rubber.

100 parts by weight of the dry rubber, 40 parts by weight of HAF carbon black, 2 parts by weight of antioxidant, 3 parts by weight of ZnO, 1 part by weight of stearic acid, 0.3 parts by weight of potassium stearate, 1.0 parts of sodium stearate (metal soap) After the addition, 1.5 parts by weight of tetramethylthiuramdisulfide and 1.0 parts by weight of sulfur were kneaded at 50 ° C. and 50 rpm using a Hake mixer, followed by a roll mill. After preparing a rubber sheet (sheet) at 2 minutes and 50 ℃ condition using a 16 minutes press at 180 ℃ to prepare a vulcanized specimen.

Comparative example  4 to 6

Examples 4 to 8 except that the polymers prepared in Comparative Examples 1 to 3 (C1 to C3) and NBR latex (TSC 25%, AN content 42%) was blended to the contents shown in Table 2 below. It carried out in the same way.

Comparative example  7

Except for using only NBR latex (TSC 25%, AN content 42%), and the blending step was not carried out in the same manner as in Examples 4 to 8.

[ Test Example ]

The properties of the modified NBR prepared in Examples 4 to 8 and Comparative Examples 4 to 7 were measured by the following method, and the results are shown in Table 2 below.

* Hardness: Measured according to Korean Industrial Standard KSM 6518 2-6.

* Tensile strength: measured according to Korean Industrial Standard KSM 6518 2-4.

* Heat resistance: Measured according to Korean Industrial Standard KSM 6518 2-7 (158 ± 2 ℃, 72 hours).

* Oil resistance: measured by volume change rate (%) after immersion for 72 hours in ASTM # 3 oil at 150 ℃.

* Compressive permanent shrinkage: measured according to the Korean Industrial Standard KSM 6518 2-10 (100 ± 2 ℃, 72 hours).

division Example Comparative example 4 5 6 7 8 4 5 6 7 NBR AN42% 75 50 25 75 75 75 75 75 100  Rubber modifier E1 25 50 75 E2 25 E3 25 C1 25 C2 25 C3 25 Mechanical properties Hardness (shore A) 75 82 88 72 71 73 75 72 70 Tensile Strength (kgf / cm ² ) 125 156 187 118 109 120 120 95 100 % Elongation 385 372 355 390 395 375 365 320 420 Heat resistance Hardness change rate (%) +10 +7 +4 +12 +11 +24 +11 +15 +25 Tensile Strength Change (%) -13 -12 -5 -14 -13 -37 -12 -13 -55 Elongation rate of change (%) -8 -5 -6 -9 -11 -46 -10 -15 -45 Oil resistance Volume change rate (%) +12 +17 +15 +15 +18 +13 +55 +57 +66 Permanent Compression Shrinkage (%) 15 18 17 16 16 25 16 17 18

As shown in Table 2, NBR (Examples 4 to 8) modified using the rubber modifier of the present invention has all mechanical properties, heat resistance and oil resistance, etc., compared to NBR (Comparative Example 7) without using the rubber modifier. It was confirmed that the excellent, the composition and content of the rubber modifier of the present invention, but NBR (Comparative Example 4) modified by using a rubber modifier that does not have a core-shell structure is significantly lowered in heat resistance, NBR (Comparative Example 5) modified by using a rubber modifier without introducing a hydrophilic monomer was significantly inferior in oil resistance, and NBR (Comparative Example 6) modified using a rubber modifier without introducing a core-shell structure or a crosslinkable monomer. It was confirmed that the mechanical properties and oil resistance both significantly decreased.

Claims (15)

Has a core-shell structure with a crosslinking reaction site, The core is a polymer formed by polymerizing a monomer mixture including an acrylic monomer, a hydrophilic monomer, and a crosslinkable monomer having a crosslinking reaction site, and is included in an amount of 50 to 95 wt% based on the total content of the core-shell latex, The shell is a methacrylic polymer, characterized in that it comprises 5 to 50% by weight relative to the total content of the core-shell latex Rubber modifiers. The method of claim 1, The monomer mixture is characterized in that it comprises 45 to 99 parts by weight of the acrylic monomer, 0.5 to 50 parts by weight of the hydrophilic monomer and 0.5 to 5 parts by weight of the crosslinking monomer having a crosslinking reaction site with respect to 100 parts by weight of the core. Rubber modifiers. The method of claim 1, The shell is a methacryl polymer polymerized from 5 to 99 parts by weight of a methacryl monomer, 0.5 to 90 parts by weight of an acrylic monomer and 0.5 to 5 parts by weight of a crosslinkable monomer having a crosslinking reaction site with respect to 100 parts by weight of the cell. Characterized by Rubber modifiers. The method of claim 1, The hydrophilic monomer is selected from the group consisting of 2-methoxyethyl (meth) acrylate, (meth) acrylic acid, hydroxylethyl (meth) acrylate, acrylonitrile, itaconic acid and maleic acid. It is characterized by one or more Rubber modifiers. The method of claim 1, The crosslinkable monomer is composed of allyl (meth) acrylate, cyclopentyl (meth) acrylate, norbornene (meth) acrylate, glycidyl (meth) acrylate, vinyl chloroacetate and 2-chloroethylvinyl ether At least one member selected from the group Rubber modifiers. The method of claim 1, The rubber modifier is acrylonitrile-butadiene rubber (NBR) modifier, characterized in that Rubber modifiers. The modifier according to claim 1 and acrylonitrile-butadiene rubber (NBR) are crosslinked. Modified acrylonitrile-butadiene-based rubbers. The method of claim 7, wherein The modifier is 0.5 to 99.5 parts by weight, the acrylonitrile-butadiene rubber (NBR) is characterized in that 0.5 to 99.5 parts by weight Modified acrylonitrile-butadiene-based rubbers. The method of claim 7, wherein The acrylonitrile-butadiene rubber (NBR) has a weight average molecular weight of 200,000 to 2000,000, an acrylonitrile content of 20 to 50% by weight, and a gel content of 5% by weight or less. Modified acrylonitrile-butadiene-based rubbers. The method of claim 7, wherein The modifier is a weight average molecular weight of 500,000 to 3000,000, characterized in that the gel content is 5% by weight or less Modified acrylonitrile-butadiene-based rubbers. The method of claim 7, wherein The crosslinking may be performed by blending, coagulating and drying the modifier and acrylonitrile-butadiene-based rubber (NBR), followed by carbon black, antioxidant, zinc oxide (ZnO), stearic acid, metal soap, and vulcanization activator. activator and sulfur, characterized in that the kneading Modified acrylonitrile-butadiene-based rubbers. Preparing a acrylonitrile-butadiene rubber composition by blending, flocculating and drying the modifier according to claim 1 with acrylonitrile-butadiene rubber (NBR); And prescribing and kneading the rubber composition with carbon black, an antioxidant, zinc oxide (ZnO), stearic acid, metal soap, metal vulcanization activator, and sulfur.  Method for producing modified acrylonitrile-butadiene rubber. The method of claim 12, The modifier is 0.5 to 99.5 parts by weight, the acrylonitrile-butadiene rubber (NBR) is characterized in that 0.5 to 99.5 parts by weight Method for producing modified acrylonitrile-butadiene rubber. The method of claim 12, The acrylonitrile-butadiene rubber (NBR) has a weight average molecular weight of 200,000 to 2000,000, an acrylonitrile content of 20 to 50% by weight, and a gel content of 5% by weight or less. Method for producing modified acrylonitrile-butadiene rubber. The method of claim 12, The modifier, the weight average molecular weight is 500,000 to 3000,000, the gel content is characterized in that 5% by weight or less Method for producing modified acrylonitrile-butadiene rubber.