JP2015013973A - Acrylic rubber composition and vulcanized molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic rubber composition and a vulcanized molded product capable of preventing deterioration in physical properties and improving non-adhesiveness.SOLUTION: An acrylic rubber composition is a polymer of α-olefin represented by the general formula: CH=CHR, where R represents an alkyl group having a carbon number of 3 to 12. In the acrylic rubber composition, with respect to 100 pts.wt. of acrylic rubber, 0.5 to 10 pts.wt. of an α-olefin oligomer having a number average molecular weight of 250 to 2000 is added. It is preferable that Tg of the acrylic rubber be -15°C or less.

Description

  The present invention relates to an acrylic rubber composition and a vulcanized molded product, and more particularly to an acrylic rubber composition and a vulcanized molded product that can improve non-stickiness.

  Since acrylic rubber (ACM) is excellent in heat resistance and oil resistance, it is widely used as a sealing material, a hose material, etc., for example, in the field of automobiles.

  However, in ACM, adhesion to a sealed kneader or an open roll, and adhesion between fabrics and products (vulcanized molded products) are likely to occur.

  In order to improve the adhesion to the kneader or the like, usually, a measure of adding ester wax, paraffin wax, or silicon oil processing aid is used.

  However, the addition of these processing aids does not sufficiently solve the various adhesive problems of ACM, and also leads to a decrease in physical properties, in particular, a permanent compression that affects the durability of rubber parts. Distortion is reduced (Comparative Examples 2, 3, and 4). In addition, many processing aids with relatively small physical properties are expensive, and when used, the unit cost of the dough increases. In actual use, there is also a concern about cost.

  Patent Document 1 says that good non-adhesiveness can be obtained by a combination of a specific ACM and an amine compound. However, since the specific ACM must be used, it cannot be said to be general-purpose.

  In addition, it is conceivable to reduce adhesion problems by using ethylene-acrylic rubber (AEM) excellent in non-adhesiveness to metal surfaces, or by partially blending, but as described in Patent Document 1. In addition, since AEM may be inferior in oil resistance as compared with ACM, it may not be able to sufficiently meet the demand for oil resistance.

  Conventionally, anti-sticking agents such as talc are applied to fabric adhesive, and silicone oil is applied to product adhesive, which may cause molding defects and foreign matter contamination during molding. There is room for improvement because it will increase the number.

  On the other hand, in order to solve the problem of special sticking that occurs when AEM and EPDM are blended under specific conditions, the present applicant has been based on 100 parts by weight of AEM. , Containing 1 to 40 parts by weight of α-olefin oligomer (Patent Document 2). This solved the problem of special sticking that occurs when AEM and EPDM are blended under specific conditions.

JP 2003-221383 A WO2006 / 132225

  The applicant further studied the possibility of α-olefin oligomers, and when blended with acrylic rubber (ACM), the applicant has a wide range of effects on various adhesive defects regardless of polymer, filler, and crosslinking system. It was found that it can be demonstrated.

  As described in Patent Document 2, the α-olefin oligomer itself was recognized to rather deteriorate the adhesion with a kneader or a roll, but surprisingly, when blended with acrylic rubber, It was found that the α-olefin oligomer bleeded on the compound surface during kneader discharge or roll kneading reduces adhesion with the kneader or roll. In addition, it was found that the physical property deterioration at that time was extremely small as compared with conventionally used processing aids, and there was almost no influence on other physical properties such as oil resistance.

  Furthermore, it has been found that the same effect can be obtained in the kneaded dough and the molded product, and the adhesion between the dough and the products can be prevented.

  Therefore, an object of the present invention is to provide an acrylic rubber composition and a vulcanized molded product that can prevent deterioration of physical properties and improve non-adhesiveness.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

1. For 100 parts by weight of acrylic rubber,
An α-olefin polymer represented by the general formula CH ₂ ═CHR (wherein R represents an alkyl group having 3 to 12 carbon atoms) and having a number average molecular weight of 250 to 2000 An acrylic rubber composition added with 0.5 to 10 parts by weight.

  2. 2. The acrylic rubber composition as described in 1 above, wherein Tg of the acrylic rubber is −15 ° C. or lower.

  3. 3. The acrylic rubber composition according to 1 or 2, wherein the acrylic rubber contains an alkoxyalkyl acrylate.

  4). 4. The acrylic rubber composition as described in any one of 1 to 3, wherein the acrylic rubber contains a carboxyl group.

  5. A vulcanized molded product obtained by vulcanizing and molding the acrylic rubber composition according to any one of 1 to 4 above.

  6). 6. The vulcanized molded product according to 5 above, wherein the α-olefin oligomer contained in the acrylic rubber composition has a number average molecular weight of 250 or more and 1400 or less.

  According to the present invention, it is possible to provide an acrylic rubber composition and a vulcanized molded product that can prevent deterioration of physical properties and improve non-stickiness.

  Below, the form for implementing this invention is demonstrated.

  The acrylic rubber composition of the present invention is obtained by adding a specific α-olefin oligomer to the acrylic rubber. Thereby, the fall of the physical property of an acrylic rubber composition is prevented, and the effect which can improve non-adhesiveness is acquired.

  The vulcanized molded product of the present invention is a product obtained by vulcanizing and molding the above acrylic rubber composition. Thereby, the fall of the physical property of a vulcanization molding can be prevented, and the effect which can improve non-adhesiveness is acquired.

(Α-olefin oligomer)
The α-olefin oligomer used in the present invention comprises one or more α-olefins represented by the general formula CH ₂ ═CHR (where R represents an alkyl group having 3 to 12 carbon atoms). Polymerized polymer.

  The addition amount of the α-olefin oligomer is in the range of 0.5 to 10 parts by weight, preferably in the range of 2 to 6 parts by weight with respect to 100 parts by weight of the acrylic rubber.

  The α-olefin oligomer of the present invention has a number average molecular weight Mn in the range of 250 to 2000, preferably 1400 or less, more preferably 1000 or less, and still more preferably 700 or less.

  The number average molecular weight can be determined by gel permeation chromatography (GPC).

  In the present invention, if the number average molecular weight is 2000 or less, the bleed is further promoted due to poor compatibility with the acrylic rubber composition or the vulcanized molded product thereof, and the compound surface is removed during kneader discharge or roll kneading. The α-olefin oligomer that is bleed is remarkable in reducing the adhesion to the kneader and roll.

  In addition, the viscosity of the α-olefin oligomer is not particularly limited as long as the number average molecular weight Mn is in a range naturally specified by the range of 250 to 2000.

  The kinematic viscosity at 100 ° C. of the α-olefin oligomer is, for example, preferably 100 cSt or less, more preferably 50 or less, still more preferably 20 or less, and most preferably 10 or less.

  In the present invention, the α-olefin oligomer may be prepared by mixing two or more α-olefin oligomers having different number average molecular weights or viscosities. In the present invention, since the non-adhesive property that is expressed may vary depending on the number average molecular weight or viscosity of the α-olefin oligomer, the advantages of each other can be obtained by mixing various α-olefin oligomers. Taking advantage of this, it will be possible to exhibit better non-adhesiveness.

  For example, an α-olefin oligomer having a high molecular weight (for example, a number average molecular weight of 1500 or more) or a high viscosity (for example, a kinematic viscosity of 50 cSt or more) is used for a medium / low molecular weight (for example, a number average molecular weight of 1400 or less) or a medium / low viscosity (for example, a kinematic viscosity). It is also preferable to use a mixture with an α-olefin oligomer of 20 cSt or less).

  The non-tackiness brought about by the present invention is mainly due to the fact that an α-olefin oligomer having poor compatibility with an acrylic rubber composition or a vulcanized molded product thereof is bleed from the composition or the vulcanized molded product. Can be expressed. Therefore, by adjusting (controlling) the bleed of the α-olefin oligomer, it is possible to adjust the timing at which non-adhesiveness is exhibited. The adjustment of the bleed may include, for example, a case where the bleed amount is controlled over time.

  The method for adjusting the bleed is not particularly limited, and can be adjusted by the amount of α-olefin oligomer added, for example. In the present invention, a particularly preferable method for adjusting the bleed is to use the fact that the α-olefin oligomer is a polymer, for example, by appropriately setting the molecular weight of the monomer and the degree of polymerization, thereby adjusting the molecular weight (viscosity) of the α-olefin oligomer. To adjust and thereby adjust the bleed.

  According to the present invention, since the α-olefin oligomer is a polymer, its molecular weight (viscosity) can be set appropriately and easily, and this has the effect of increasing the degree of freedom of the timing to exhibit non-adhesiveness. Is done.

  According to the present invention, by setting the molecular weight (viscosity) of the α-olefin oligomer as appropriate, or by blending those having different molecular weights (viscosity), for example, a point effect is imparted to a point where processability is desired to be improved. It becomes possible.

  From the above, as one aspect, the present invention imparts non-adhesiveness to the rubber composition or the vulcanized molded product by bleeding the non-adhesive component from the rubber composition or the vulcanized molded product. When adjusting the molecular weight or viscosity of the non-adhesive component, or by combining multiple non-adhesive components with different molecular weights or viscosities, the bleeding can be adjusted to control the expression of non-adhesiveness. More preferably, it can also be said that the non-adhesive component is a polymer, so that the molecular weight or viscosity can be set easily and appropriately.

(Acrylic rubber)
The acrylic rubber (also referred to as ACM polymer) in the present invention is a rubber obtained by copolymerizing one or a plurality of acrylic esters and a crosslinking point monomer as a main component monomer, and what is called ethylene-acrylic rubber (also referred to as AEM polymer). Differentiated.

  In the present invention, by using acrylic rubber, the non-adhesive improvement effect brought about by the α-olefin oligomer is widely exhibited for various adhesive defects regardless of the polymer, filler, and crosslinking system. It becomes like this. Such an effect is difficult to obtain when acrylic rubber is not used as the rubber (for example, in the case of Patent Document 2 described above). In order to achieve the effect of the present invention, EPDM blend as in Patent Document 2 is not necessary.

  Preferred examples of the acrylic rubber used in the present invention include those obtained by copolymerizing alkyl acrylate or alkoxyalkyl acrylate, butyl acrylate, and a crosslinking point monomer.

  Examples of the alkyl acrylate include ethyl acrylate (EA).

  Examples of the alkoxyalkyl acrylate include methoxyethyl acrylate (MEA), methoxybutyl acrylate, ethoxyethyl acrylate, ethoxybutyl acrylate, and the like.

  In the present invention, the acrylic rubber is particularly preferably one obtained by copolymerizing an alkoxyalkyl acrylate, butyl acrylate, and a crosslinking point monomer.

  As the crosslinking point monomer, those containing an active chlorine group, those containing a carboxyl group, and the like can be preferably used as the crosslinking point, and those containing a carboxy group are particularly preferred.

  Examples of the crosslinking point monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, 2-pentenoic acid, maleic acid, fumaric acid, itaconic acid, maleic acid monoalkyl ester, fumaric acid monoalkyl ester, itaconic acid mono Examples include alkyl esters.

  Examples of the crosslinking point monomer having a chlorine group (including an active chlorine group) include 2-chloroethyl vinyl ether, 2-chloroethyl acrylate, vinyl benzyl chloride, vinyl chloroacetate, and allyl chloroacetate.

  In the present invention, the glass transition temperature (Tg) of the acrylic rubber is preferably −15 ° C. or lower. When it is -15 ° C or lower, the low-temperature sealability is excellent, and when it exceeds -15 ° C, the low-temperature sealability is poor.

  The ACM polymer of the present invention can be obtained as a commercial product, and examples of the commercial product include “NOXITE PA522”, “NOXITE PA401”, and “NOXITE PA404K” manufactured by Unimatec.

(Other ingredients)
If the acrylic rubber composition of the present invention contains an acrylic rubber and an α-olefin oligomer, the effects of the present invention are exhibited. In addition to the above, the effects of the present invention can be obtained even when an acrylic rubber composition further containing other compounding agents is used.

  Other compounding agents are not particularly limited, but rubbers such as carbon black, vulcanizing agent (crosslinking agent), vulcanization accelerator (crosslinking accelerator), processing aid, acid acceptor, anti-aging agent, plasticizer, etc. The compounding agent generally used by industry can be mentioned.

  The compounding amount of the carbon black is preferably in the range of 40 to 100 parts by weight, more preferably in the range of 50 to 90 parts by weight with respect to 100 parts by weight of the acrylic rubber.

  Examples of commercially available carbon black that can be preferably used in the present invention include “N330 carbon black” manufactured by Showa Cabot Corporation.

  Further, silica may be used in combination with carbon black or in place of carbon black. Silica can be produced by the pyrolysis method of halogenated silicic acid or organosilicon compounds, dry silica produced by heat reduction of silica sand and air oxidation of vaporized SiO, etc., produced by pyrolysis method of sodium silicate, etc. An amorphous silica can be preferably used, and a commercially available product such as “Nippil (nip seal) LP” manufactured by Tosoh Silica Industry Co., Ltd. can be used. When silica is used, it is also preferable to use a silane coupling agent in combination.

  As the vulcanizing agent (crosslinking agent) and the vulcanization accelerator (crosslinking accelerator), those capable of forming a crosslinking structure with a crosslinking point monomer component of acrylic rubber or those capable of promoting the formation thereof are used. Depending on the type of point, it can be selected as appropriate.

  For example, when an acrylic rubber contains an active chlorine group as a cross-linking point, as an example, sulfur or the like is preferably used as a vulcanizing agent (cross-linking agent).

  When the acrylic rubber contains a carboxyl group as a cross-linking point, as an example, an alkylene diamine or the like is preferably used as a vulcanizing agent (cross-linking agent), and a guanidine compound as a vulcanizing accelerator (cross-linking accelerator). Is preferably used.

  The alkylene diamines may be aliphatic or aromatic. For example, hexamethylene diamine, hexamethylene diamine carbamate, N, N′-dicinnamylidene-1,6-hexane diamine, 4,4′- Methylene bis (cyclohexylamine) carbamate, 4,4′-methylenedianiline, 4,4′-oxyphenyldiphenylamine, m-phenylenediamine, p-phenylenediamine, 4,4′-methylenebis (o-chloroaniline), 4, 4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4 '-(m-phenylenediisopropylidene) dianiline, 4,4'-(p-phenylenediisopropylidene) dianiline, 2,2'-bis [4- (4-Aminophenoxy) phenyl] pro 4,4′-diaminobenzanilide, 4,4′-bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, hexamethylenediamine-cinnamaldehyde adduct and hexamethylenediamine Examples thereof include dibenzoate salts.

  In the present invention, among these, hexamethylenediamine carbamate, N, N′-dicinnamylidene-1,6-hexanediamine, 4,4′-methylenebis (cyclohexylamine) carbamate, and 4,4′-diaminodiphenyl ether are preferable. The product can be used as it is. For example, a commercial product of hexamethylenediamine carbamate is Diak No. No. 1 (manufactured by DuPont Dow Elastomer Co., Ltd.), and a commercial product of N, N′-dicinnamylidene-1,6-hexanediamine is Diak No. 3 (manufactured by DuPont Dow Elastomer Co., Ltd.), and a commercial product of 4,4′-methylenebis (cyclohexylamine) carbamate is Diak No. 4 (manufactured by DuPont Dow Elastomer Co., Ltd.), and a commercial product of 4,4′-diaminodiphenyl ether is DADPE (manufactured by Sun Chemical Co., Ltd.).

  Examples of the guanidine-based compound include 1,3-diphenylguanidine, 1,3-dioltolylguanidine (other name: ditolyl-o-guanidine), tetramethylguanidine, dibutylguanidine, and the like. Processing aids composed of such guanidine compounds can be obtained as commercial products, and examples of the commercial products include “Noxeller DT” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

  Preferred examples of the processing aid include fatty acids such as stearic acid and palmitic acid or metal salts thereof.

(Kneading)
The acrylic rubber composition of the present invention can be kneaded using a kneading apparatus such as a sealed kneader (pressure kneader) or an open roll.

  According to the acrylic rubber composition of the present invention, adhesion to an apparatus (particularly a kneader or a roll) can be suitably prevented during kneading. Thereby, not only the productivity is improved, but also the work that the operator has performed for the adhesion to the kneader or the roll can be reduced, and the effect of further improving the safety can be achieved.

(Vulcanization)
When the acrylic rubber composition of the present invention is vulcanized (crosslinked), the acrylic rubber composition containing components necessary for vulcanization (crosslinking) is heated. The heating temperature is not particularly limited and can be appropriately set. For example, the heating temperature is preferably 130 to 220 ° C, more preferably 140 to 200 ° C, still more preferably 150 to 200 ° C, and the vulcanization (crosslinking) time. Is preferably 30 seconds to 5 hours, more preferably 3 minutes to 60 minutes.

  As a heating method, a method used for crosslinking of rubber such as press heating, steam heating, oven heating, hot air heating and the like may be appropriately selected.

  In addition, secondary crosslinking may be performed after the primary crosslinking in order to ensure crosslinking to the inside of the crosslinked product. The secondary crosslinking varies depending on the heating method, crosslinking temperature, shape, etc., but the heating temperature is preferably 150 to 250 ° C., and the heating time is preferably 0.5 hours to 24 hours. As the heating method, oven heating or the like may be selected as appropriate.

  The acrylic rubber composition of the present invention exhibits the effects of the present invention even in a vulcanized molded product after vulcanization molding of the acrylic rubber composition.

  The method for molding the rubber composition of the present invention is not particularly limited. Any method such as compression molding, injection molding, transfer molding or extrusion molding can be used.

  In the present invention, an injection molding machine, a compression molding machine, a vulcanizing press, or the like may be used, either a method of simultaneously performing molding and crosslinking, or a method of performing crosslinking after molding.

  If it is the acrylic rubber composition thru | or vulcanized molding of this invention, the effect excellent in the mold release property from the metal mold | die used at the time of shaping | molding is also show | played.

  Although the use of the vulcanized molded product of the present invention is not particularly limited, it can be suitably used as a sealing part such as a sealing material for fixing (gasket) or a sealing material for exercise (packing). Moreover, when an O-ring is formed from the vulcanized molded product of the present invention, it can be suitably used as a gasket or packing.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
<Blend ingredients and blending amounts>
-ACM1 (Unimatec "NOXITE PA522") 100 parts by weight-N330 carbon black 60 parts by weight-4,4'-bis (α, α-dimethylbenzyl) diphenylamine (anti-aging agent) 1 part by weight-Poly-α- 2 parts by weight of olefin (medium viscosity) 2 parts by weight of stearic acid 0.6 parts by weight of hexamethylenediamine carbamate 2 parts by weight of di-o-tolylguanidine

  ACM1 is a carboxyl group-containing ACM, and the polymer Tg is −31 ° C.

  The poly-α-olefin (medium viscosity) has a kinematic viscosity at 100 ° C. of 7.8 cSt, and the number average molecular weight Mn (polystyrene conversion) determined by gel permeation chromatography (GPC) is 630.

<Evaluation method>
-Creation of a test piece The various compounding which concerns on the said Example 1 was knead | mixed in the normal procedure using the sealed kneading machine and the open roll, and the unvulcanized material was produced.
For normal value measurement, air heat aging test and immersion test, unvulcanized dough was press vulcanized at 180 ° C. for 8 minutes in a 2 mm thick sheet molding die, and then for 10 hours in an atmosphere at 175 ° C. By performing secondary vulcanization, a 2 mm thick vulcanized sheet as a test piece was obtained.
The compression set O-ring for compression set had an inner diameter of 24.4 mm and a wire diameter of 3.1 mm, and was obtained by molding using a dedicated mold under the same conditions as the 2 mm sheet.

・ Evaluation of workability [kneader discharge] (3-level evaluation)
After kneading in a sealed kneader, the dischargeability when discharged from the kneader was evaluated according to the following criteria.
○: The dough can be discharged as a whole, and there is no dough residue or dirt in the discharged tank.
Δ: The dough can be discharged as a whole, but there is dough residue and dirt in the tank.
X: The dough cannot be discharged as a whole. The dough sticks and cannot be discharged smoothly. Furthermore, dough residue and dirt are conspicuous in the tank after discharge.

[Roll adhesiveness] (3 step evaluation)
When kneading with an open roll, non-adhesiveness to the roll was evaluated according to the following criteria.
○: There is no adhesion to the roll, and kneading (turning, rounding, dispensing, etc.) can be performed without any problem regardless of the thickness of the dough.
Δ: Kneading can be carried out without problems if the thickness of the dough is thick, but when the thickness of the dough is thin, a sticky feeling is felt.
X: The dough sticks to the roll, and kneading is extremely difficult by a normal method.

[Fabric non-adhesiveness] (4-level evaluation)
The dough immediately after kneading with an open roll was layered, and the non-adhesiveness when peeled off in a sufficiently cooled state was evaluated according to the following criteria. In addition, weight was not used but the cloth adhesion only by the weight of the cloth was evaluated.
(Double-circle): It does not adhere at all.
○: There is almost no sticky feeling and can be easily peeled off.
Δ: Although there is a sticky feeling, it can be peeled off.
X: It adheres strongly and cannot be removed. Alternatively, one fabric is integrated with the other fabric and cannot be peeled off at the original interface.

[Mold releasability] (4 step evaluation)
Using a mold with 12 O-rings with an inner diameter of 24.4 mm and a wire diameter of 3.1 mm, the mold releasability is evaluated according to the following criteria based on the mold release time without using a release agent and when using an air gun. did.
(Double-circle): The mold release is possible and the mold release time is also within 3 seconds.
○: Integrated release is possible, and the release time is more than 3 seconds and within 10 seconds.
Δ: Can be released as a single unit, but cannot be released with air alone, and needs some assistance. The mold release time is within 30 seconds.
X: Unable to release integrally, O-ring and burrs stick to the mold. The mold release time is 30 seconds or more.

[Non-adhesiveness of molded products] (3 stage evaluation)
Two molded 2 mm thick sheets were bonded together, and the non-adhesiveness at the time of peeling was evaluated according to the following criteria.
○: There is no sticky feeling and can be easily peeled off.
Δ: Although there is a sticky feeling, it can be peeled off.
X: It adheres strongly and cannot be removed. Or even if it peels off, an adhesive surface becomes rough or a sheet | seat deform | transforms with the force to peel off.

-Normal state physical property measurement About the obtained 2 mm thickness vulcanized sheet, rubber hardness Hs, breaking strength (tensile strength) Tb (MPa), and breaking elongation Eb (%) were evaluated by the following methods.
Rubber hardness Hs; Hs hardness was measured according to JIS K6253 (1997) DuroA (instantaneous).
Breaking strength (tensile strength) Tb (MPa); measured according to JIS K6251 (2010).
Elongation at break Eb (%): Measured according to JIS K6251 (2010) (23 ± 3 ° C.).

-Compression set test About the obtained compression set O-ring, the compression set was measured according to JIS K6262 (2006) at a compression rate of 25%, a test temperature of 175 ° C, and a test time of 70 hours.

-Air heat aging test About the obtained 2 mm thickness vulcanization | cure sheet | seat, based on JISK6257 (2010), the normal state physical property change (rate) after a 175 degreeC x 70-hour heating was evaluated. Specifically, the rubber hardness Hs was determined as a change from the normal physical properties. Moreover, about the breaking strength (tensile strength) Tb and breaking elongation Eb, the change rate from the said normal state physical property was calculated | required.

・ Immersion test About the obtained 2 mm thick vulcanized sheet, the rubber hardness Hs after the immersion test (condition: the sample was immersed in JIS No. 3 oil at 150 ° C. for 70 hours) in accordance with JIS K6258 (2003), rupture The strength (tensile strength) Tb, the breaking elongation Eb and the volume are measured, and the rubber hardness Hs is a change from the above-mentioned normal physical properties, and the breaking strength (tensile strength) Tb and the breaking elongation Eb is the above-mentioned normal physical properties. The rate of change was determined by comparing the rate of change with the value before and after immersion. The smaller these changes are, the more preferable as the present invention.

  The results are shown in Table 1.

<Content of poly-α-olefin>
(Example 2)
In Example 1, except that 2 parts by weight of the poly-α-olefin (medium viscosity) was changed to 6 parts by weight, a vulcanized molded product was similarly molded and evaluated in the same manner, and the results are shown in Table 1.

Example 3
In Example 1, except that 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 10 parts by weight, a vulcanized molded product was molded in the same manner and evaluated in the same manner, and the results are shown in Table 1.

Example 4
In Example 1, except that 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 0.5 parts by weight, a vulcanized molded product was molded and evaluated in the same manner, and the results are shown in Table 1. It was.

(Comparative Example 1)
In Example 1, except that 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 0 parts by weight, a vulcanized molded product was molded in the same manner and evaluated in the same manner, and the results are shown in Table 1.

(Comparative Example 2)
In Example 1, 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 0 parts by weight, and 2 parts by weight of silicone processing aid (“WS280” manufactured by SCHILL & SEILACHER) was added as a processing aid. Similarly molded vulcanized products and evaluated in the same manner, and the results are shown in Table 1.

(Comparative Example 3)
In Example 1, 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 0 parts by weight, and a vulcanized molded product was similarly formed except that 2 parts by weight of paraffin wax was added as a processing aid. Evaluation was conducted in the same manner, and the results are shown in Table 1.

(Comparative Example 4)
In Example 1, 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 0 part by weight, and a vulcanized molded product was molded in the same manner except that 2 parts by weight of sodium stearate was added as a processing aid. The results were similarly evaluated, and the results are shown in Table 1.

(Evaluation)
From Table 1, it can be seen from the comparison between Examples 1 to 4 and Comparative Example 1 that the non-adhesiveness can be improved without reducing each physical property by adding the α-olefin oligomer to the acrylic rubber.

  In particular, in Examples 1 and 2 and the like in which the addition amount of the α-olefin oligomer is 2 to 6 parts by weight, it can be seen that the prevention of deterioration of physical properties and the improvement of various non-adhesive properties are suitably achieved.

  Moreover, compared with Examples 1-3 and Comparative Examples 2-4, compared with the addition of ester wax, paraffin wax, and silicon oil type processing aids that have been conventionally used for improving tackiness, α-olefins are used. It was clearly proved that the addition of oligomers was more effective in improving non-tackiness. Furthermore, the physical property fall accompanying non-adhesive improvement was not seen.

<Viscosity of poly-α-olefin>
(Example 5)
In Example 1, except that 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 2 parts by weight of poly-α-olefin (low viscosity), a vulcanized molded product was molded and evaluated in the same manner, The results are shown in Table 2.

  The poly-α-olefin (low viscosity) has a kinematic viscosity at 100 ° C. of 3.9 cSt, and the number average molecular weight Mn (polystyrene conversion) determined by GPC is 440.

(Example 6)
In Example 1, except that 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 2 parts by weight of poly-α-olefin (high viscosity), a vulcanized molded product was molded and evaluated in the same manner, The results are shown in Table 2.

  The poly-α-olefin (high viscosity) has a kinematic viscosity at 100 ° C. of 100 cSt, and the number average molecular weight Mn (polystyrene conversion) determined by GPC is 2000.

(Evaluation)
In Examples 1, 5 and 6, when the viscosity of the poly-α-olefin was changed, it was confirmed that the non-adhesive property to be expressed changed. When a low-viscosity poly-α-olefin is used, its non-tackiness is particularly effective for fabric adhesion, and when a high-viscosity poly-α-olefin is used, its non-tackiness is particularly gold. It turns out that it is effective for mold release.

  In addition, in the case of using a low-viscosity poly-α-olefin, the effect of improving the non-adhesiveness is widely exhibited for various adhesion defects including adhesion to a kneader and a roll. I understand.

  Furthermore, it is clear from the comparison between Example 6 and Comparative Example 1 using a high-viscosity poly-α-olefin that the deterioration of physical properties can be prevented and non-adhesiveness can be improved. It was shown that non-adhesiveness can be significantly improved by using a medium-low viscosity poly-α-olefin together with a high-viscosity poly-α-olefin in terms of other than mold release.

<Diversity of ACM polymer>
(Example 7)
In Example 1, 60 parts by weight of N330 carbon black was changed to 60 parts by weight of nip seal LP, which was silica, and vulcanization molding was similarly performed except that 1 part by weight of γ-aminopropyltriethoxysilane was added as a silane coupling agent. Articles were molded and evaluated in the same manner, and the results are shown in Table 3.

(Example 8)
In Example 1, 100 parts by weight of ACM1 was 100 parts by weight of ACM2, 2 parts by weight of stearic acid was 3 parts by weight of sodium stearate, 0 parts by weight of hexamethylene carbamate and di-o-tolylguanidine, and 0. Except for adding 5 parts by weight, a vulcanized molded product was molded and evaluated in the same manner. The results are shown in Table 3.

  Here, ACM2 (corresponding to “NOXITE PA401” manufactured by Unimatec) is an active chlorine group-containing ACM, and the polymer Tg is −17 ° C.

Example 9
In Example 1, 100 parts by weight of ACM1 is 100 parts by weight of ACM3, 2 parts by weight of poly-α-olefin (medium viscosity) is 4 parts by weight, 2 parts by weight of stearic acid is 3 parts by weight of sodium stearate, hexamethylene Vulcanized moldings were similarly molded and evaluated in the same manner except that 0 parts by weight of carbamate and di-o-tolylguanidine and 0.5 parts by weight of sulfur were added. The results are shown in Table 3.

  Here, ACM3 (corresponding to “NOXITE PA404K” manufactured by Unimatec) is an active chlorine group-containing ACM, and the polymer Tg is −44 ° C.

(Comparative Example 5)
In Example 1, 60 parts by weight of N330 carbon black was changed to 60 parts by weight of nip seal LP which was silica, 1 part by weight of γ-aminopropyltriethoxysilane was added as a silane coupling agent, and poly-α-olefin (medium viscosity) was added. Except for changing 2 parts by weight to 0 parts by weight, a vulcanized molded product was molded in the same manner and evaluated in the same manner. The results are shown in Table 3.

(Comparative Example 6)
In Example 1, 100 parts by weight of ACM1 was 100 parts by weight of ACM2, 2 parts by weight of stearic acid was 3 parts by weight of sodium stearate, 0 parts by weight of hexamethylene carbamate and di-o-tolylguanidine, and 0. A vulcanized molded product was molded in the same manner except that 5 parts by weight was added and 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 0 part by weight, and evaluated in the same manner. The results are shown in Table 3. .

(Comparative Example 7)
In Example 1, 100 parts by weight of ACM1 is 100 parts by weight of ACM3, 2 parts by weight of stearic acid is 3 parts by weight of sodium stearate, 0 part by weight of hexamethylene carbamate and di-o-tolylguanidine, and 0. A vulcanized molded product was molded in the same manner except that 5 parts by weight was added and 2 parts by weight of poly-α-olefin (medium viscosity) was changed to 0 part by weight, and evaluated in the same manner. The results are shown in Table 3. .

(Evaluation)
As can be seen from the comparison between Examples 7 to 9 and Comparative Examples 5 to 7, regardless of the type of ACM (for example, polymer type), the composition of the composition (for example, filler type), and the crosslinking system, α -It was confirmed that the effect of the present invention was achieved by the addition of the olefin oligomer.

Claims (6)

For 100 parts by weight of acrylic rubber,
An α-olefin polymer represented by the general formula CH ₂ ═CHR (wherein R represents an alkyl group having 3 to 12 carbon atoms) and having a number average molecular weight of 250 to 2000 An acrylic rubber composition added with 0.5 to 10 parts by weight.   The acrylic rubber composition according to claim 1, wherein the acrylic rubber has a Tg of −15 ° C. or lower.   The acrylic rubber composition according to claim 1 or 2, wherein the acrylic rubber contains an alkoxyalkyl acrylate.   The acrylic rubber composition according to claim 1, wherein the acrylic rubber contains a carboxyl group.   A vulcanized molded product obtained by vulcanizing and molding the acrylic rubber composition according to any one of claims 1 to 4. The vulcanized molded product according to claim 5, wherein the α-olefin oligomer contained in the acrylic rubber composition has a number average molecular weight of 250 or more and 1400 or less.