JP2001002867A - Center bearing support - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a center bearing support exhibiting an excellently low dynamic-to- static modulus ratio and excellent in durability and ozone resistance by molding a vulcanizate of a chlorinated polyethylene having a Mooney viscosity of a specific value or higher and a chlorine content of a specific value or higher. SOLUTION: There is provided a composition comprising a chlorinated polyethylene having a Mooney viscosity MS1+4 (100 deg.C) of at least 55 and a chlorine content of 25-35 wt.% having incorporated therein a vulcanizing agent, an acid acceptor such as an oxide or a hydroxide of a divalent metal, hydrotalcite or the like, a reinforcing agent or filler such as carbon black, silica or the like, each in a specified amount, and further, if necessary, a plasticizer, an antioxidant, a softening agent, a tackifier and the like. The composition is kneaded and subsequently vulcanization-molded by means of a compression molding machine or the like at a temperature of 140-250 deg.C and a pressure of 2-50 MPa for 1-30 min to give a molded product. As the vulcanizing agent, there can be mentioned organic oxides, trithiocyanurate compounds, thiourea compounds and the like, and the organic peroxides are used jointly with a polyfunctional unsaturated compound such as triallylcyanurate or the like and a crosslinking auxiliary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a center bearing support. More specifically, the present invention relates to a center bearing support excellent in low dynamic magnification, durability, ozone resistance, low-temperature characteristics, and the like.

[0002]

2. Description of the Related Art In recent years, as the output and performance of automobiles have increased, the environment in the vicinity of a center bearing support for vibration-proofing and supporting a propeller shaft (a shaft for transmitting driving force from an engine to a rear wheel differential) has been exposed to high temperatures. There is an increasing demand for improved heat resistance of the materials used for this. In addition, improvements in durability for improving reliability and vibration-proofing for quietness of automobiles are also required.

Conventionally, as a molding material for the center bearing support, natural rubber, natural rubber / SBR blend rubber,
Chloroprene rubber has been used, but in response to recent demands for improved performance of center bearing supports, natural rubber has heat resistance, while natural rubber / SBR blend rubber and chloroprene rubber have durability and ozone resistance. Therefore, it is becoming difficult to satisfy the functions. Furthermore,
Further reduction in dynamic magnification is also required.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide a low dynamic magnification (a small increase in the elastic modulus due to an increase in the deformation speed of rubber), durability (proof strength against destruction by repeated deformation of rubber), and durability. It is an object of the present invention to provide a center bearing support having excellent ozone properties (resistance to deterioration and physical property change of rubber due to ozone).

[0005]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
Achieved by a center bearing support consisting of a chlorinated polyethylene vulcanizate with a Mooney viscosity MS _{1 + 4} (100 ° C.) of 55 points or more and a chlorine content of 25 to 35% by weight.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Chlorinated polyethylene has a Mooney viscosity MS _{1 + 4} (100 ° C.) (based on JIS K-6300) of 55 points or more, preferably about 60 to 100 points, and a chlorine content of 25 points. What is used is -35% by weight, preferably 30-33% by weight. When Mooney viscosity is less than this,
If the tensile strength is not sufficient, and if the tensile strength is more than this, molding as a rubber material becomes difficult. Even with a chlorine content of less than this, molding processing as a rubber material becomes difficult.On the other hand, when a material with a chlorine content of more than this is used, the low-temperature characteristics are reduced and the function as a center bearing support is satisfied. Disappears.

As a vulcanizing agent for chlorinated polyethylene, at least one of organic peroxide, trithiocyanuric acid (mercaptotriazine), thiourea, quaternary phosphonium, etc. is used. In the case of 1,3,5-triazine-2,4-dithiol, it may be used in combination with an organic peroxide (JP-A-62-79247). Further, an organic peroxide is generally used in combination with a polyfunctional unsaturated compound such as triallyl isocyanurate and triallyl cyanurate and a crosslinking aid, and a thiourea vulcanizing agent may be used in combination with thiurams ( JP-A-2-34644).

In addition to the vulcanizing agent, an acid acceptor comprising an oxide or hydroxide of a divalent metal, a hydrotalcite, a reinforcing agent or a filler such as carbon black or silica is added to the chlorinated polyethylene. , And if necessary, a plasticizer,
An anti-aging agent, a softening agent, an anti-adhesive agent and the like are added and used as processing aids for improving material properties, fabric processing and molding.

The above components are kneaded using an open roll, a Banbury mixer, a kneader or the like, and the kneaded material is heated at about 14 ° C. using a heat compression molding machine, an injection molding machine, or an injection molding machine.
It is vulcanized and formed on the center bearing support under the conditions of 0 to 250 ° C, pressure of about 2 to 50 MPa, and time of about 1 to 30 minutes.

[0010]

As described above, the center bearing support according to the present invention has excellent durability at a tensile strength, the number of occurrences of cracks in a dematcher bending test, and an anti-vibration property indicated by a dynamic magnification without substantially impairing the low-temperature characteristics. In particular, excellent improvements are achieved in terms of ozone resistance and the like.

[0011]

Next, the present invention will be described with reference to examples.

Example 1 100 parts by weight of chlorinated polyethylene (Osaka Soda product Daisolak N130) [MS _{1 + 4} (100 ° C.) 60, chlorine content 30%] SRF-HS carbon black (Tokai Carbon Product Seast SVH) 20〃 Magnesium oxide (Kyowa Chemicals Kyomag # 150) 10 〃 Anti-aging agent (Ouchi Emerging Chemicals Nocrack RD) 1 ジ オ Dioctyl sebacate 10 〃 Sulfur 0.1 〃 Organic peroxide (Sanperox TY-1.3 ) 3 〃 Triallyl isocyanurate (Nippon Kasei's product Tyke M60) 3 〃 Knead each of the above ingredients with a kneader.
It was compression molded under the conditions of 0 MPa and 10 minutes.

The following items were measured for the vulcanized product. Normal properties: Conforms to JIS K-6310 Air heating aging test: Changes in normal properties after 70 hours at 100 ° C Compression set: 100 ° C, 70 hours Kd 400 Hz / Kst (dynamic magnification): When the deformation rate is 1% / sec Ratio of the elastic modulus of the material when the deformation rate is 400% / sec to the elastic modulus of the material Kst 80 ℃ / Kst 25 ℃ ： The ratio of the static elastic modulus of the material at 80 ℃ to the static elastic modulus of the material at 25 ℃ de Mattia flex test: crack occurrence frequency measurement Gehman torsion test: T ₁₀₀ value measured ozone resistance test (low temperature properties): ozone concentration 50 pphm, 40 ° C., 0 to 20% deformation, visually cracking time in 1Hz dynamic conditions Measure

Example 2 Chlorinated polyethylene (Daisorac N130) 100 parts by weight SRF-HS carbon black (Seast SVH) 20 〃 Magnesium oxide (Kyomag # 150) 10 〃 Antioxidant (Nocrack RD) 1 〃 Dioctyl sebacate 10 〃 Trithiocyanuric acid (Sankyo Kasei product Disnet OF 100 / 0.7) 2 Vulcanization accelerator (Osaka Soda product M 181 / 0.7) 4 Vulcanization and measurement were carried out in the same manner as in Example 1 using the above components. Was done.

Example 3 In Example 2, as a chlorinated polyethylene, Daisorac N135 [MS _{1 + 4} (100 ° C.) 53, manufactured by Osaka Soda;
5%] was used.

Comparative Example 1 In Example 2, as chlorinated polyethylene, Daisorac RA135 [MS _{1 + 4} (100 ° C.) 32, manufactured by Osaka Soda;
35%] was used.

Comparative Example 2 In Example 2, as chlorinated polyethylene, Showa Denko Eraslen 401A [MS _{1 + 4} (100 ° C.) 100, chlorine content 40
%] Was used.

Comparative Example 3 In Example 2, as chlorinated polyethylene, Showa Denko Eraslen 403A [MS _{1 + 4} (100 ° C.) 50, chlorine content 40]
%] Was used.

Comparative Example 4 The same measurement as in Example 1 was performed on a vulcanized chloroprene rubber material for a center bearing support (180 ° C., 4 minutes).

Comparative Example 5 The same measurement as in Example 1 was performed on a vulcanized product (150 ° C., 10 minutes) of a natural rubber / SBR blend rubber material for a center bearing support.

The measurement results in the above Examples and Comparative Examples are shown in the following table. Table Example Comparative Example Measurement Item Standard Value 1 2 3 1 2 3 4 5 [Normal Physical Property] Hardness (JIS A) 60 to 70 66 67 66 63 69 66 69 64 100% Modulus (MPa) 2.0 to 6.0 2.5 3.8 3.5 2.4 4.0 3.8 4.2 3.7 Tensile strength (MPa)> 18 24.5 22.0 19.6 14.0 21.5 11.0 15.7 17.4 Elongation (%)> 300 430 400 350 240 380 150 390 430 [Air heating aging test] Hardness change (point) Max. + 5 +4 +2 +1 +2 +2 +1 +3 +6 Tensile strength change (%) Max.-20 +20 +10 +7 -1 -3 +4 +2 -8 Elongation change (%) Max. -20 +2 -5 -3 -6 -10 -5 -9 -26 [Permanent set] 100 ° C, 70 hours (%) Max 40 21 30 27 27 22 45 54 36 [Kd400Hz / Kst] Modulus ratio Max 2.5 2.05 1.80 2.33 2.85 3.33 3.80 5.03 2.37 [Kst 80 ° C / Kst 25 ° C] Modulus of elasticity Max 1.5 0.80 0.82 0.83 0.86 0.92 1.10 0.65 0.90 [Dematia bending test] Number of cracks (× 10 ⁴ times)>100>100>100> 100 45> 100 72> 100 <5 [Geman torsion test] T ₁₀₀ (℃) <-40 -43 -43 -40 -38 -34 -32 -44 -53 [Ozone resistance] Visual cracking (time )>100>200>200>200>200>200> 200 70 10

From the above results, the following can be said. Example 1: It is preferable that the value of the number of cracks generated by the tensile strength and the dematcher bending test is large, and that the value of the dynamic magnification of the center bearing support material is small, but this is also a small value. The vulcanization system was changed from a peroxide system to a trithiocyanuric acid system, but rubber material properties such as tensile strength, number of cracks generated by a dematcher bending test, and dynamic magnification showed good values. with 35% the amount of chlorinated polyethylene, ₁₀₀ value T by Gehman torsion test although a slight drop in (low-temperature properties) and dynamic factor is observed, Comparative examples are excellent in balance of the center bearing support member as a whole 1 : When a polymer having a low Mooney viscosity is used, the tensile strength and the number of occurrences of cracks in a dematcher bending test are significantly reduced. When the knee viscosity increases and use of polymers having a high chlorine content, although the tensile strength and crack count by de Mattia flex test show good value, Comparative Example decreases significantly the Gehman torsion test ₁₀₀ value T by (low temperature properties) 3: Mooney viscosity use large polymer decreases also the chlorine content, the tensile strength and not by de Mattia flex test crack number only, Gehman ₁₀₀ value T by a torsion test significant comparative example reduction of (low-temperature characteristics) 4: The chloroprene rubber material generally used as a center bearing support material has a lower tensile strength, a higher dynamic magnification, and an inferior ozone resistance as compared with those of the examples. 5: Natural rubber for center bearing support / SBR
In the case of the blended rubber material, as compared with those of the examples,
In particular, the number of cracks generated by the dematcher bending test and the ozone resistance are poor.

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[Procedure amendment]

[Submission date] July 9, 1999 (1999.7.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art In recent years, as the output and performance of automobiles have increased, the environment in the vicinity of the center bearing support, which supports the propeller shaft (shaft that transmits the driving force from the engine to the rear wheel differential), has become hotter. tend, there is a growing improved heat resistance requirements material used for this. In addition, improvements in durability for improving reliability and vibration-proofing for quietness of automobiles are also required.

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Claims (1)

[Claims] 1. A center bearing support comprising a vulcanized chlorinated polyethylene having a Mooney viscosity MS _{1 + 4} (100 ° C.) of 55 points or more and a chlorine content of 25 to 35% by weight.