JPH07331015A - Plasticizr for acrylic rubber - Google Patents

Abstract

PURPOSE:To provide a plasticizer for acrylic rubber which comprises a specific polyether plasticizer and a linear polyester plasticizer and can be formulated in acrylic rubber to be used as a packing for vehicles because it is excellent in compatibility, processability, moldability and resistances to heat, coldness and oil. CONSTITUTION:This plasticizer for acrylic rubber comprises (A) a polyether plasticizer of a condensate of a polyoxyethylene monoalkyl ether prepared by addition reaction of 4-8 moles, on the average, of ethylene oxide to a monoalkyl alcohol of 6-18 carbon atoms such as n-hexanol with an aliphatic dicarboxylic acid such as adipic acid and (B) a linear polyester plasticizer of 800-1,600 number average molecular weight which is prepared by polycondensation reaction of an aromatic ring-free aliphatic glycol with an aliphatic dicarboxylic acid and terminating the polymer chain with an alkyl monoalcohol or monocarboxylic acid. The weight ratio of the component A/the component B is preferably in the range of (30-70)/(70-30).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for industrial parts such as packings for vehicles, O-rings, oil seals, fuel hoses, belts, diaphragms, etc., which are required to have heat resistance, cold resistance and oil resistance. The present invention relates to a plasticizer for acrylic rubber that is blended with the acrylic rubber.

[0002]

2. Description of the Related Art Nitrile rubber (NBR) is a functional rubber that has been most often used for special purposes such as industrial parts. However, with the recent sophistication of required properties, when properties that cannot be obtained with nitrile rubber are required, it is necessary to use a functional rubber with improved heat resistance inherent to rubber such as acrylic rubber if it has heat resistance. Don't However, acrylic rubber has a drawback that it is inferior in kneading property, moldability and processing property of a compounding agent as compared with nitrile rubber and the like.

For this reason, compounding agents which have been conventionally compounded with acrylic rubbers such as plasticizers, carbon, lubricants, and anti-aging agents have been studied in order to improve the defects, and packings for vehicles, O
-Has been used as industrial parts such as rings, oil seals, fuel hoses, belts, and diaphragms. However, improvement with these compounding agents has not been satisfied.

Further, as plasticizers that have been conventionally used in acrylic rubber, ether ester based dibutoxyethoxyethyl adipate and dibutoxyethoxyethoxyethyl glutarate (Japanese Patent Publication No. 54-44695) and dioctyl are mainly used. Phthalates such as phthalates (DOP), trioctyl trimellitate (TO
TM) and other trimellitic acid triesters,
These plasticizers have a problem in heat resistance. On the other hand, adipic acid-based polyester or the like having good heat resistance has a problem in cold resistance.

Recently, a special polyether ester system as reported in JP-A-3-59045 and JP-A-5-230288 has been used as a plasticizer capable of providing heat resistance and cold resistance. ing. However, these have not been satisfactory in terms of kneadability, moldability and processing characteristics which are problems of acrylic rubber.

[0006]

The object of the present invention is to achieve a good balance between kneading, moldability and processability, which is a problem of acrylic rubber, because it is well compatible with acrylic rubber for these problems. Another object of the present invention is to provide a plasticizer for acrylic rubber which can improve and maintain the heat resistance, cold resistance and oil resistance which are the unique properties of acrylic rubber.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a polyether plasticizer obtained by condensing an acrylic rubber with an aliphatic polycarboxylic acid and an alkoxypolyoxyethylene alcohol. It has been found that the problem can be solved by blending (A) and the linear polyester plasticizer (B) containing no aromatic ring, and has completed the present invention.

That is, the present invention comprises (A) a polyether plasticizer obtained by condensing an aliphatic polycarboxylic acid with an alkoxypolyoxyethylene alcohol, and (B) a linear polyester plasticizer containing no aromatic ring. The present invention provides a plasticizer for acrylic rubber, which preferably has a carbon number of 6 to 18 as a plasticizer to be blended with acrylic rubber.
A polyether plasticizer obtained by a condensation reaction of a polyoxyethylene monoalkyl ether obtained by adding 4 to 8 moles of ethylene oxide to a monoalkyl alcohol which is an alkyl dicarboxylic acid and an aliphatic dicarboxylic acid having 5 to 10 carbon atoms (A )
And an aliphatic glycol having 3 to 6 carbon atoms and 5 to 10 carbon atoms
Of the linear polyester plasticizer (B) having a number average molecular weight of 800 to 1600, which is obtained by condensing the aliphatic dicarboxylic acid with a monoalkyl alcohol or a monoalkyl carboxylic acid as a terminating agent. ) /
(B) = 30 to 70/70 to 30 (% by weight), a plasticizer for acrylic rubber and a composition thereof. Furthermore, by blending the plasticizer for acrylic rubber of the present invention with acrylic rubber, kneading, moldability and workability, which are problems of acrylic rubber, are improved in a well-balanced manner, and heat resistance which is a unique property of acrylic rubber is improved. The present invention has led to the provision of a plasticizer for acrylic rubber that can improve and retain the properties, cold resistance and oil resistance.

(Structure) The plasticizer for acrylic rubber of the present invention is a polyether plasticizer (A) obtained by condensing an aliphatic dicarboxylic acid with an alkoxypolyoxyethylene alcohol.
And a linear polyester plasticizer containing no aromatic ring (B)
It is a mixture with.

The polyether plasticizer (A) is preferably obtained by a condensation reaction of a polyoxyethylene monoalkyl ether obtained by adding 4 to 8 mol of ethylene oxide on average to a monoalkyl alcohol, and an aliphatic dicarboxylic acid. .

The monoalkyl alcohol which can be used as the polyether plasticizer (A) constituting the plasticizer for acrylic rubber of the present invention is preferably an alcohol having one hydroxyl group in the molecule and having 6 to 18 carbon atoms. For example, n-hexanol, isohexanol, n-heptanol, isoheptanol, n-octanol, isooctanol, 2-ethylhexanol, n-nonanol,
Linear or branched alcohols such as isononanol, n-decanol, isodecanol, isoundecanol, lauryl alcohol, tridecanol, cetyl alcohol and stearyl alcohol and mixtures thereof can be preferably used.

The polyether type plasticizer (A) of the present invention is
These monoalkyl alcohols are preferably obtained by condensation reaction of polyoxyethylene monoalkyl ether having 4 to 8 mol of ethylene oxide added on average and an aliphatic dicarboxylic acid. It is inferior in properties, and if it exceeds 8 moles, it solidifies and is difficult to use.

The aliphatic dicarboxylic acid referred to herein is preferably an aliphatic dicarboxylic acid having 5 to 10 carbon atoms,
Examples thereof include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. If the carbon number is larger than 10, a bleeding problem occurs, and if it is smaller than 4, cold resistance becomes problematic, which is not preferable. Particularly technically and economically, the use of adipic acid and / or glutaric acid is preferred.

The linear polyester plasticizer (B) constituting the acrylic rubber plasticizer of the present invention is preferably a condensation product of an aliphatic glycol and an aliphatic dicarboxylic acid, and a monoalkyl alcohol or monoalkyl as a terminating agent. It is a condensation reaction of a carboxylic acid. The aliphatic glycol is preferably an aliphatic glycol having 2 to 6 hydroxyl groups in the molecule and having 3 to 6 carbon atoms.
-Propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl -1,5-pentanediol,
1,6-hexanediol and the like can be mentioned, and one or more of them can be used.

The aliphatic dicarboxylic acid is preferably an aliphatic dicarboxylic acid having 5 to 10 carbon atoms, such as glutaric acid, adipic acid, pimelic acid, suberic acid,
Azelaic acid and sebacic acid are mentioned, and one or more of them can be used. The terminator for setting the molecular weight of the linear polyester is preferably a monoalkyl alcohol or a monoalkylcarboxylic acid, and examples of the monoalkyl alcohol include isohexanol, isoheptanol, n-octanol, 2-ethylhexanol, Examples thereof include isononanol, and examples of the aliphatic dicarboxylic acid include acetic acid, octylic acid, 2-ethylhexoic acid, isodecanoic acid, neodecanoic acid, and lauric acid, and one or more of these can be used.

The linear polyester plasticizer (B) of the present invention
Is preferably a polyester plasticizer having a number average molecular weight of 800 to 1600, which is obtained by condensation of the above-mentioned aliphatic glycol and aliphatic dicarboxylic acid and condensation reaction of the above-mentioned monoalkyl alcohol or monoalkylcarboxylic acid as a terminating agent. And can be obtained by a condensation reaction.
If the number average molecular weight is less than 800, the heat resistance and oil resistance of the acrylic rubber will be poor, and if it is more than 1600, the cold resistance will be poor.

The plasticizer for acrylic rubber of the present invention can be obtained by mixing the polyether plasticizer (A) obtained from these materials with the linear polyester plasticizer (B). The ratio is preferably (A) / (B) = 30-
70/70 to 30 (% by weight).

The acrylic rubber to which the plasticizer for acrylic rubber of the present invention can be blended is generally a polymer using one or more of alkyl acrylate and / or alkoxyalkyl acrylate, and alkyl acrylate and / or
Or 2- or more of one or more alkoxyalkyl acrylates
It is a copolymer of chloroethyl vinyl ether or acrylonitrile, and a copolymer of one or more of alkyl acrylate and / or alkoxyalkyl acrylate, such as vinyl acetate and ethylene. The alkyl component of the alkyl acrylate that constitutes the acrylic rubber is an alcohol residue such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butyl alcohol. As the alkoxyalkyl component of the alkoxyalkyl acrylate, methoxymethanol, ethoxymethanol,
2-methoxyethanol, 2-ethoxyethanol, 2
-It means an alcohol residue such as butoxyethanol.

The acrylic rubber to which the plasticizer for acrylic rubber of the present invention can be blended is in the molecule of the polymer and / or copolymer mainly containing these alkyl acrylates and / or alkoxyalkyl acrylates. A rubber elastomer having a chlorine group, an active chlorine group, an epoxy group, an unsaturated group, a carboxyl group or the like, which can usually serve as a crosslinking point. These acrylic rubbers are commercially available from rubber manufacturers such as Nippon Synthetic Rubber Co., Ltd., Nippon Zeon Co., Ltd., Nippon Mektron Co., Ltd., Toa Paint Co., Ltd., Showa Denko / Dupont Co., Ltd., and Denki Kagaku Kogyo Co., Ltd.

The plasticizer of the present invention is preferably added to the acrylic rubber in an amount of 1 to 30 parts by weight. If it is less than 1 part by weight, it is difficult to plasticize, and if it is more than 30 parts by weight, bleeding is not preferable.

In addition to the plasticizer of the present invention, many compounding agents are usually compounded in the acrylic rubber. The plasticizer for acrylic rubber of the present invention is preferably compounded together with these compounding agents, and as a general compounding agent other than the plasticizer, a rubber reinforcing agent such as carbon, an antioxidant, a rubber vulcanizing agent is used.・ There are cross-linking agents, vulcanization accelerators, vulcanization acceleration aids, scorch inhibitors, UV inhibitors, mastication accelerators, fillers, lubricants, etc. These are "Handbook rubber and plastic compound chemicals" issued by Rubber Digest. (Revised second edition: October 30, 1993) ", which can be used in the present invention.

The plasticizer for acrylic rubber of the present invention is blended at the same time with acrylic rubber and its compounding agent to prepare packings for vehicles, O-rings, oil seals, fuel hoses, belts,
It can be used for molding industrial parts such as diaphragms, which have features.

[0023]

EXAMPLES The present invention is described in detail below with reference to examples, but "parts" and "%" in the text are based on weight.

[Synthesis Example 1: Synthesis Example of Polyether Plasticizer (Prototype-1)] Hexaoxyethylene-2-ethylhexyl ether (trade name; Blaunon EH-6: Aoki Yushi Industrial Co., Ltd.) 946 g, adipic acid 146 g, 33 g of toluene, and 0.1 g of tetraisopropyl titanate (TiPT) are weighed and set in a 3 liter four-necked flask, heated to 230 ° C., decantation gradually removes generated water, and esterified. A condensation reaction is performed, and when the acid value becomes 2.0 or less, decompression is started, and at 230 ° C., the pressure is reduced to 5 mmHg or less, and toluene and unreacted alcohol are removed. When the effluent disappeared, the reduced pressure was released, the temperature was lowered, and the mixture was filtered through diatomaceous earth and taken out to obtain a yield of 1010 g. This synthetic product is referred to as prototype-1.

Example 1 Prototype-1 obtained in Synthesis Example 1 and Polycizer W-1510 (linear polyester plasticizer, number average molecular weight 1500: Dainippon Ink and Chemicals, Inc.) were mixed at 50/50 (% by weight). The plasticizer of the present invention mixed in the above) is referred to as prototype-4.

[Synthesis Example 2: Synthesis Example of Polyether Plasticizer (Prototype-2)] 734 g of tetraoxyethylene-2-ethylhexyl ether (trade name; Blaunon EH-4: Aoki Yushi Industrial Co., Ltd.), adipic acid 146 g, 26 g of toluene, and 0.1 g of tetraisopropyl titanate (TiPT) are weighed and set in a 3 liter four-necked flask, heated to 230 ° C., decantation gradually removes generated water, and esterified. A condensation reaction is performed, and when the acid value becomes 2.0 or less, decompression is started, and at 230 ° C., the pressure is reduced to 5 mmHg or less, and toluene and unreacted alcohol are removed. When the effluent disappeared, the reduced pressure was released, the temperature was lowered, and diatomaceous earth was filtered out to obtain 820 g of a yield. This synthetic product is referred to as prototype-2.

Example 2 Prototype-1 obtained in Synthesis Example 2 and Polycizer W-1510 (linear polyester plasticizer, number average molecular weight 1500: Dainippon Ink and Chemicals, Inc. product) were mixed at 50/50 (% by weight). The plasticizer of the present invention mixed in)) is referred to as prototype-5.

[Synthesis Example 3: Synthesis Example of Polyether Plasticizer (Prototype-3)] Pentaoxyethylene Mixed Alkyl (C12-13) Ether (Brandon DAL)
-5: Aoki oil and fat industrial product) 996 grams, adipic acid 1
46 g of toluene, 34 g of toluene, and 0.1 g of tetraisopropyl titanate (TiPT) were weighed in a 3 liter four-necked flask, heated to 230 ° C., and gradually dewatered to remove the produced water to carry out an esterification condensation reaction. When the acid value becomes 2.0 or less, the pressure reduction is started, and the pressure is reduced to 5 mmHg or less at 230 ° C. to remove toluene and unreacted alcohol. When the effluent disappeared, the reduced pressure was released, the temperature was lowered, and diatomaceous earth was filtered to take out, and a yield of 1055 g was obtained. This synthetic product is referred to as prototype-3.

Example 3 Prototype-1 obtained in Synthesis Example 3 and Polycizer W-320 (linear polyester plasticizer,
The number average molecular weight of 1000: Dainippon Ink and Chemicals Inc. product) was mixed at 50/50 (% by weight), and the plasticizer of the present invention is designated as Prototype-6.

[Compounding Example] In the comparative evaluation of the plasticizer for acrylic rubber of the present invention, an active chlorine type cold acrylic type commercial acrylic rubber having the slowest roll cohesion (compatibility) was used as the acrylic rubber, and this compounding was used. It shows in Table 1.

[0031]

[Table 1]

The explanation of (1) to (6) in Table 1 is as follows. (1) AREX210: Activated chlorine-based acrylic rubber (product of Nippon Synthetic Rubber Co., Ltd.) (2) Seast 116: MAF carbon (product of Tokai Carbon Co., Ltd.) (3) Nocrac CD: Antiaging agent (product of Ouchi Shinko Co., Ltd.) (4) Nonsar SN-1: Sodium stearate (Nippon Yushi Co., Ltd. product) (5) Nonsar SK-1: Potassium stearate (Nippon Yushi Co., Ltd. product) (6) Salfax PMC: Sulfur (Tsurumi Chemical Industry Co., Ltd. product)

Examples 4 to 6 and Comparative Examples 1 to 6 Acrylic rubber and its compounding agent shown in Table 1 and the plasticizer of the present invention were kneaded at room temperature using two rolls having a diameter of 6 inches. The cohesion time (compatibility) and the roll kneading homogenization time were measured.

[0034]

[Table 2]

From Table 2, it can be seen that the plasticizer for acrylic rubber of the present invention has a good cohesion time (compatibility) on a roll and a uniform kneading time, and is excellent in workability.

The explanation of (7) to (14) in Table 2 is as follows. (7) Prototype-4: The plasticizer produced in Example 1 as a trial. (8) Prototype-5: The plasticizer produced as a trial in Example 2 above. (9) Prototype-6: The plasticizer produced as a trial in Example 3 above. (10) DOP: Dioctyl phthalate (product of Dainippon Ink and Chemicals) (11) Monosizer W-700: Trioctyl trimellitate (product of Dainippon Ink and Chemicals) (12) Monosizer W-260: adipic acid Dibutyl diglycol (Product of Dainippon Ink and Chemicals, Inc.) (13) Monosizer W-262: Polyethylene glycol 300 dioctoate (Product of Dainippon Ink and Chemicals, Inc.) (14) RS-735: Polyetherester plasticizer (Asahi Denka Co., Ltd. Industrial product)

[Examples 7 to 9 and Comparative Examples 7 to 11] With respect to the unvulcanized sheets kneaded in Table 2, the plastic coder (P
The rubber vulcanization characteristics were measured with L-2000 type: manufactured by Brabender. The measurement was carried out under the conditions of 170 ° C. and 30 rpm,
57 g of unvulcanized sheet was charged, and the time from the start of kneading to the start of vulcanization and the time from the start of vulcanization to the 80% vulcanization point were measured.

[0038]

[Table 3]

From Table 3, by incorporating the plasticizer for acrylic rubber of the present invention, the molding time (pot life) from the start of kneading to the start of vulcanization is long, and the time from the start of vulcanization to 80% vulcanization is It turns out that it is effective in shortening.

The explanation of (15) to (17) in Table 3 is as follows. (15) Prototype-1: The polyether plasticizer obtained in Synthesis Example 1 above. (16) Prototype-2: The polyether plasticizer obtained in Synthesis Example 2 above. (17) Trial product-3: The polyether plasticizer obtained in Synthesis Example 3 above.

[Examples 10 to 12, Comparative Examples 12 to 14]
The unvulcanized sheet that was roll-kneaded in Table 2 was heated to 170 ° C. × 20
Minutes (press primary vulcanization), 175 ° C. × 4 hours (second oven vulcanization), and the physical properties of the vulcanized sheet were evaluated.

[0042]

[Table 4]

[Evaluation test] Heat resistance: JISK-6380 Reference "Air heating aging test (175 ° C x 336 hours)" Oil resistance: JISK-6380 "No. 3 oil immersion test (1)
50 ° C x 70 hours) "Cold resistance: JISK-6301" low temperature torsion test "

[Evaluation] ○: Good, Δ: A little bad, ×: Poor, XX: Very bad From Table 4, the plasticizer for acrylic rubber of the present invention shows good results such as heat resistance, cold resistance and oil resistance. It turns out that

The explanation of (18) in Table 4 is as follows. (18) Polycizer W-320: linear adipic acid polyester plasticizer, number average molecular weight 1000 (product of Dainippon Ink and Chemicals, Inc.)

[0046]

INDUSTRIAL APPLICABILITY The plasticizer for acrylic rubber of the present invention is excellent in compatibility with acrylic rubber (collecting time on a roll) and processability / moldability (molding time / pot life). Also, when used in combination with the compounding agent thereof, the performance of the acrylic rubber having better heat resistance, cold resistance, oil resistance and the like can be obtained.

Claims (8)

[Claims] 1. An acrylic resin comprising (A) a polyether plasticizer obtained by condensing an alkoxy polyoxyethylene alcohol with an aliphatic dicarboxylic acid, and (B) a linear polyester plasticizer containing no aromatic ring. Plasticizer for rubber. 2. The polyether plasticizer (A) comprises a polyoxyethylene monoalkyl ether obtained by adding 4 to 8 mol of ethylene oxide on average to a monoalkyl alcohol, and an aliphatic dicarboxylic acid having 5 to 10 carbon atoms. The plasticizer for acrylic rubber according to claim 1, which is produced by a condensation reaction. 3. The plasticizer for acrylic rubber according to claim 2, wherein the monoalkyl alcohol of the polyether plasticizer (A) has 6 to 18 carbon atoms. 4. The polyester-based plasticizer (B) is characterized by condensing an aliphatic glycol and an aliphatic dicarboxylic acid and subjecting a monoalkyl alcohol or a monoalkylcarboxylic acid as a terminator to a condensation reaction. The plasticizer for acrylic rubber according to claim 1. 5. The plasticizer for acrylic rubber according to claim 1, wherein the polyester plasticizer (B) has a number average molecular weight of 800 to 1600. 6. The plasticizer for acrylic rubber according to claim 4, wherein the aliphatic glycol of the polyester plasticizer (B) has 3 to 6 carbon atoms. 7. The plasticizer for acrylic rubber according to claim 4, wherein the aliphatic dicarboxylic acid of the polyester plasticizer (B) has 5 to 10 carbon atoms. 8. The mixing ratio of the polyether plasticizer (A) and the polyester plasticizer (B) is (A) / (B) = 3.
It is 0-70 / 70-30 (weight%), The plasticizer for acrylic rubbers of Claim 1 characterized by the above-mentioned.