JPH01207346A - Composition having rubber elasticity - Google Patents

Abstract

PURPOSE:To obtain a composition having excellent mechanical properties, water resistance, oil resistance and rubber elasticity, by blending a hydrogenated block copolymer of a vinyl aromatic compound and an olefinic compound and/or a modified material thereof with acrylic rubber. CONSTITUTION:(A) 1-99 pts.wt. A1: hydrogenated block copolymer having <=20% degree of unsaturation of olefinic compound polymer block, obtained by hydrogenating a block copolymer which consists of one or more, preferably two or more vinyl aromatic compound polymer blocks and one or more olefinic compound polymer block and has 20,000-500,000 number-average molecular weight and <=10 molecular weight distribution and/or A2: modified material obtained by adding <=20 pts.wt. unsaturated carboxylic acid (derivative) to 100 pts.wt. component A1 is blended with (B) 99-1 pt.wt. acrylic rubber and optionally 0.05-10 pts.wt. based on 100 pts.wt. total amounts of the components A and B of a vulcanizing agent to give a rubber elastic composition.

Description

[Detailed Description of the Invention] <Industrial Application Field> The invention is based on the invention by blending a hydrogenated block copolymer and/or its modified product with acrylic rubber, resulting in high mechanical properties, water resistance, and oil resistance. This composition has rubber elasticity and excellent chemical resistance.

<Conventional technology> In recent years, automobile engine system parts and plant piping parts? 4
! Rubbers with excellent heat resistance and oil resistance, such as special rubbers such as silicone rubber, acrylic rubber, fluororubber, and nitrile rubber, are used in the field of parts after scattering.
Among these, acrylic rubber is widely used because it has excellent heat resistance, weather resistance, oil resistance at high temperatures, and is inexpensive.

In addition, thermoplastic elastomers such as polystyrene elastomers, polyolefin elastomers 1. T? Various types of elastomers are useful, such as lJ ester elastomers, polyurethane elastomers, and polyvinyl chloride elastomers. Among these, styrene-butadiene block copolymers (e.g. 8BS)
and styrene-isoprene/block copolymers (e.g. SI
S) is highly flexible and has good rubber elasticity at room temperature, and in particular, these hydrogenated products are widely used because they have excellent weather resistance and mechanical properties.

However, each of the above-mentioned rubbers and thermoplastic nidistomers has drawbacks. Acrylic imes have the disadvantage of poor cold resistance, water resistance, mechanical properties, etc., and hydrogenated block copolymers have the disadvantages of poor oil resistance and heat resistance. Various proposals have been made to solve these drawbacks. For example, for acrylic rubber, USP -3,488+341. J, Po
Lymer Sci 15.

520 (1955), etc., discloses a method of introducing a polar group into the alkyl group of an acrylic acid alkyl ester, that is, a technique of copolymerizing those having a sulfide or ether bond, and further containing fluorine. Regarding hydrogenated block copolymers, for example,
37<518, Japanese Patent Publication No. 56-44102, Japanese Patent Publication No. 6
No. 2-20551, etc., proposes blending a hydrogenated block copolymer with a resin having high oil resistance or a resin having high heat resistance. However, even with these proposed methods, the sufficient number H of the various drawbacks mentioned above remains.
The current situation is that no improvement effect has been obtained.

<Problems to be Solved by the Invention> The present invention has been made in view of the above points, and by combining acrylic rubber and a hydrogenated block copolymer or a modified product thereof, the drawbacks of both components can be mutually overcome. In addition, it is water resistant and oil resistant. It is an object of the present invention to provide a composition having improved cold resistance, mechanical strength, and rubber elasticity.

According to the present invention, (a) a block consisting of at least one vinyl aroma-bearing compound polymer block A and at least one olefin compound production block B; A block copolymer in which the degree of unsaturation and fO of block B does not exceed 20%, and/or a block copolymer in which a carboxylic acid group or a derivative group thereof (I-absorbing molecular unit is bonded to the block copolymer) Modified block copolymer containing 1 to 99'sti parts (b) 99 to 1 parts by weight or more of acrylic rubber (aJ (1)) and optionally blended with additives such as fillers and softeners. A composition having rubber elasticity is provided.

The present invention will be described in detail below.

The block copolymer before hydrogenation of the hydrogenated block copolymer used as component (a) of the present invention includes at least one vinyl aromatic compound polymer block, preferably two or more blocks, and a conjugated diene compound. It contains at least one polymer block mainly composed of. Here, the polymer block mainly composed of conjugated diene has a weight ratio of vinyl aromatic compound to conjugated diene compound of 0/100 to 501.
50, preferably a polymer block consisting of a composition range of O/100 to 40/60, and the distribution of vinyl aromatic compounds in this block is a random taper (monomer component increases or decreases depending on molecular weight). , partially block-shaped, or any combination thereof.

In the block copolymer before hydrogenation, the weight ratio of the vinyl aromatic compound content to the conjugated diene compound content is preferably in the range of 10/90 to 90/10 cD, and when rubber-like properties are required, A range of 15/85 to 60/40 is preferred.

The vinyl aromatic compounds constituting the block copolymer before hydrogenation include styrene, α-methylstyrene 1,1-
One or more types are selected from diphenylethylene, paramethylstyrene, vinyltoluene, etc., and styrene is particularly preferred. The conjugated diene compound is selected from one or more of butadiene, imprene, 1,3-pentadiene, etc., and butadiene 2 and/or imprene are particularly preferred.

The above block copolymer has a number average molecular weight of 20.000 to
In the range of 500,000, the molecular weight distribution (ratio of weight average molecular weight to number average molecular weight) is preferably in the range of 10 or less. Furthermore, when butadiene is used as a conjugated diene compound in the block copolymer before hydrogenation, the amount of 1.2 bonds in the microstructure of the butadiene moiety is 10 to 80%.
A range of 20% to 50% is particularly preferred.

When the block copolymer before hydrogenation contains two or more blocks mainly composed of vinyl aromatic compound blocks or conjugated diene compounds, each block may have the same structure, or may have different structures. It may be. Further, the molecular structure of the hydrogenated block copolymer may be linear, branched, radial, or a combination thereof.

The hydrogenated block copolymer used in the present invention may be obtained by any production method as long as it has the above-described structure. For example, the special public interest public corporation Sho 40-237
A vinyl aromatic compound-conjugated diene compound block copolymer is synthesized in an inert solvent using a lithium catalyst or the like by the method described in No. 98, and then by a known method such as Japanese Patent Publication No. 42-8704 or Japanese Patent Publication No. By hydrogenating in an inert solvent in the presence of a hydrogenation catalyst according to the method described in No. 61-33132, not more than 20 aromatic double bonds of the vinyl aromatic compound block A and A hydrogenated block copolymer in which at least 80% of the aliphatic double bonds of the conjugated diene compound block B are hydrogenated is synthesized.

The degree of unsaturation of block B in the present invention refers to the proportion of carbon-carbon double bonds contained in block B, and this is determined by nuclear magnetic resonance absorption spectrum (NMR), infrared absorption spectrum (IR). It is measured by instrumental analysis such as, chemical analysis such as iodometry.

Further, as component (a), a hydrogenated block copolymer described above with a molecular unit containing a carboxylic acid group or a derivative thereof bonded can also be used.

Examples of unsaturated carboxylic acids or derivatives thereof added to such hydrogenated block copolymers include maleic acid, halogenated maleic acid, itaconic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, −cis-bicyclo [
2,2,1)-5-heptene-2,3-dicarboxylic acid, etc., anhydrides, esters, amides, imides, etc. of these dicarboxylic acids, and acrylic acid, methacrylic acid, crotonic acid, etc., and esters of these monocarboxylic acids, Examples include derivatives such as methyl methacrylate, glycidyl methacrylate, and amides. Among these, maleic anhydride and glycidyl methacrylate are particularly preferred.

When mixing a hydrogenated block copolymer component with a rubber component that has a polar functional group in its side chain, such as acrylic rubber, using a modified hydrogenated block copolymer will improve the dispersibility of both components. A rubber composition having improved and even better mechanical properties is obtained.

The amount of the carmenic acid group or its derivative group added to the block copolymer is 20 parts by weight or less, preferably 10 parts by weight or less, per 100 parts by weight of the hydrogenated copolymer.

Even if a large amount added exceeding this value is used, the effect of improving adhesion will reach a plateau. Such a placed-injection hydrogenated block copolymer may be used in combination of one or two or more parts, and may also be used in combination with a rice-and-wheat hydrogenated block copolymer.

Next, the acrylic rubber used as component (1) of the present invention is a rubber with improved mechanical properties such as water resistance, oil resistance, and cold resistance by blending it with the hydrogenated block copolymer of component (a). It is an essential component that provides the elastic composition vlJ, and the acrylic rubber used as component (b) mainly includes ethyl acrylate, ethyl acrylate/butyl acrylate, ethyl acrylate/dityl acrylate/methoxyethyl acrylate, ethylene/methyl acrylate, etc. halogen-containing monomers such as 2-chloroethyl vinyl ether, monochlorovinyl acetate, and allyl chloroacetate, and epoxy-containing monomers such as glycidyl methacrylate and allyl glycytyl ether as active groups for crosslinking. Examples include those containing a small amount of reactive monomers such as diene monomers such as ZEN.

The ratio of component (a) and component (b) is (aJ/(b)=9
It ranges from 9/1 to 1/99, and can be appropriately selected depending on the required physical properties. For example, if you require high mechanical properties, high water resistance, etc. (select a composition with a high Al content), if you require high heat resistance and high oil resistance (1), select a composition with a high content of Al components. All you have to do is select something.

In the present invention, (a) and (b) a mixture of both components 100
The vulcanizing agent can be used in an amount of 0.05 to 10 parts by weight. If the composition of the present invention is used as a Kinnetsucho plastic nidistomer composition, the vulcanizing agent may not be used, or it may be used in a small amount to the extent that fluidity is not impaired.
When used as a vulcanized rubber composition, a commonly used vulcanizing agent may be used. A preferred composition when used as a thermo-oT plastic nidistomer composition is (al/
(b+ is 20/80 or more, more preferably 4
It is 0/60 or more. When used as a rubber composition for vulcanization, the preferred composition is (a)/(b) of 80/20 or less, more preferably 60/40 or less.

If the composition is outside these ranges, the physical properties of the thermoplastic nidistomer composition or the physical properties of the vulcanizable rubber composition after vulcanization will deteriorate, making it undesirable.

As specific examples of additives used in the present invention, various additives such as sulfur-based, peroxide-based, and amine-based additives can be used. Examples of sulfur-based compounds include sulfur, morpholine disulfide, alkylphenol disulfide, and thiuram polysulfide-based compounds; examples of peroxide-based compounds include dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, and 2,5-
Bis(t-butylperoxy)2,5-dimethylhexane, 2,5-dimethyl-2,5-zo(penzoylperoxy)hexane, t-butylperbenzoate, sheet t
-butyl peroxide, α,α′-bis(1-butylperoxy)diisopropylbenzene, 1,1-bis(
(t-butylperoxy)-6,5,5-trimethylcyclohexane, t-butylperoxyisopropyl carbonate, etc., and amines include hexamethylenediamine carbamate, hexamethylenetetramine, triethyltrimethylenetriamine, 2- Examples include mercaptoimidacillin, ammonicum bendeeate, dimethyldithiocarbamate salt, guanidine, methylenecyaniline, and the like.

The composition of the present invention is composed of (aJ acid component (b) component or these and a vulcanizing agent, but in addition to these, additives such as a thermoplastic resin, a filler, a softener, etc.) may preferably be blended. Thermal 0T plasticity (!f) is useful for improving the fluidity, mechanical strength, etc. of the composition of the present invention, especially of compositions exhibiting thermoplastic properties.The thermoplastic resin is preferably a polyolefin resin. Resins such as polyethylene, polypropylene, polybdenum, block copolymers and random copolymers of propylene and α-olefins such as ethylene or 1-butene can be used. The amount used should be kept within a range that does not impair the flexibility of the composition having rubber elasticity, but as a general guideline, (a
) (b) About 0 to 80 g per 100 parts by weight of the composition including both components. Furthermore, inorganic fillers can be added to the composition of the present invention. The inorganic filler is useful for increasing the hardness of the resulting composition having rubber elasticity and for improving economic efficiency as an extender. Examples of the S optical agent include calcium carbonate, Merck, clay, synthetic silicon, titanium oxide, Cargin black, 4JA
Paricum t-acid and the like can be used. The amount of inorganic filler used should be kept within a range that does not impair the flexibility of the resulting rubber-elastic composition. The amount is about 0 to 100 parts by weight per 100 parts by weight of the blended composition.

Furthermore, other additives such as a vulcanization accelerator, a crosslinking aid, a lubricant, a coloring agent, an oxidative deterioration inhibitor, a flame retardant, an anti-static agent, an anti-blocking agent, etc. may be appropriately added to the composition of the present invention. good.

The method of mixing the composition of the present invention includes an extruder, a roll,
Pampa +) - Methods used for mixing ordinary rubber or thermoplastic elastomers such as mixers can be used. Molding processing methods include extrusion molding, calendar molding, compression molding, glow molding, injection molding, etc. is applicable.

<Examples> Some examples will be shown below, but the present invention is not limited to these examples.

The physical properties measured in the Examples and Comparative Examples were conducted using the following test methods.

(1) Tensile strength (hours/cIIL'') A compression press sheet with a thickness of 2 m was used as a No. 3 test piece according to JIS-K-6301.

Measurement is based on JIS-K-6301.

(2) Elongation (ch) Based on JIS-K-6301 (3) Compression set (%) Based on JIS-K-6501. Measurement conditions were 70℃,
25% deformation, 22 hours (4) Hardness JIS-K-6301A type (5) Oil resistance and water resistance test (H) Measure volume change according to JIS-K 6301 (6
) Brittleness temperature ('0) Based on JIS-K 6501 ゛The hydrogenated block copolymer as component (a) used in Examples and Comparative Examples is described in I-1. Furthermore, the acrylim used as the component (b) is listed in Table 2.

Examples 1 to 6, Comparative Examples 1 and 2 Hydrogenated block copolymers selected from Table 1, unvulcanized acrylim selected from Table 2, naphthenic oil (pw
-380: manufactured by Idemitsu Kosan Co., Ltd.), polypropylene (Asahi Boripro E-1100: Asahi Kaseisha IA), and calcium carbonate were blended in the composition shown in Table 6, and 2,6- Add a 1.5 mi lid of sheet tert-butyl-4-methylphenol (thermal stabilizer) and 0.1 part by weight of erucic acid amide, granulate it with a twin screw extruder, and form it into a sheet with a roll. 150X150X with press
2 (mz) flat plate samples were prepared, and various physical properties were measured using predetermined methods. However, the acrylic rubber used in Examples 5 and 6 was 40 parts by weight of HAF black (Carzan black) and 1 part by weight of stearic acid per 100 parts by weight of un/111@rubber.
Naragard 445 (anti-aging agent manufactured by Uniroyal)
2 parts of ammonium benzonite and 0.8 parts of ammonium benzonite were mixed together, kneaded with a roll, and then vulcanized at 170°C for 10 minutes.
The sample was heat-treated at ℃ for 2 hours.

As shown in Examples 1 to 6, the composition of the present invention is a thermoplastic elastomer composition with excellent oil resistance and mechanical properties, especially one in which the acrylime component is lightly vulcanized,
It can be seen that when a hydrogenated block copolymer modified with a carboxylic acid derivative is used, the thermoplastic elastomer composition has particularly excellent compression set in addition to the above-mentioned physical properties.

The conventional composition shown in Comparative Example 1.2, in which no acrylic rubber component is added, exhibits poor oil resistance and poor compression set.

Examples 7 to 11, Comparative Examples 6 and 4 The hydrogenated block copolymer selected from Ibara-1 and the acrylim selected from Table-2 were blended into the composition shown in Table-4, and the blend 100 To the weight part, 50 parts by weight of HAF black, 1 part by weight of stearic acid, 1 mmg of roboguchi, and 2.5 it parts of ammonium benzony were added, mixed with a roll, and then pressed at 170'O for 1.0 minutes. , and further heat treated at 140'C for 6 hours.

As shown in Examples 7 to 11, the composition of the present invention is a vulcanized rubber composition with a low embrittlement temperature and excellent acid resistance and alkali resistance, especially a hydrogenated block modified with a carboxylic acid derivative. It can be seen that when a copolymer is used, the dispersibility with acrylim improves, resulting in a vulcanized rubber composition with excellent mechanical properties such as elongation and tensile strength. Comparative examples 3 and 4
The ordinary sulfurized acrylic rubber shown in Figure 1 has a low embrittlement temperature and is a composition with poor acid resistance and alkali resistance.

<Effects of the Invention> By cleverly combining a hydrogenated block copolymer and an acrylic rubber, the composition of the present invention has excellent water resistance and oil resistance, which does not compensate for the shortcomings of the two. It is a composition with a good balance of properties and rubber elasticity with improved mechanical properties and low-temperature properties, and is useful in the fields of various packings, marine-related sealing materials, automotive engine parts, house parts, etc. It is widely used and has great significance.

Patent applicant Asahi Kasei Industries closed company

Claims (2)

[Claims] (1) (a) A block copolymer consisting of at least one vinyl aromatic compound polymer block A and at least one olefin compound polymer block B, wherein the degree of unsaturation of block B is 20 1 to 99 parts by weight of a block copolymer or/and a modified block copolymer in which a molecular unit containing a carboxylic acid group or a derivative group thereof is bonded to the block copolymer (b) Acrylic rubber 99 to 1 A composition having rubber elasticity consisting of parts by weight. (2) A composition comprising 0.05 to 10 parts by weight of a vulcanizing agent based on 100 parts by weight of the composition according to claim 1.