JP2010189500A - Rubber composition for fender, and fender using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for a fender having low glass transition temperature, low elastic modulus even in cold climates, and excellent in fuel efficiency; and to provide a fender using the same. <P>SOLUTION: This rubber composition for a fender includes a vulcanizable rubber (A); a linear rubber (B) having a high-cis structure other than (A), and a branched rubber (C) having a high-cis structure. In particular, in the branched rubber (C) having the high-cis structure, the proportion of the 1,4-cis structure is ≥80 mol% and the ratio (Tcp/ML<SB>1+4</SB>) of the 5% toluene solution viscosity (Tcp) to the Mooney viscosity (ML<SB>1+4</SB>) at 100°C is 0.5-2.0. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention applies a ternary rubber consisting of a vulcanizable rubber, a linear rubber having a high cis structure, and a branched rubber having a high cis structure, thereby reducing the glass transition temperature. In addition, the present invention relates to the manufacture of a rubber composition for a fender having a low elastic modulus even in a cold region and excellent fuel efficiency, and a fender using the same.

As for the fenders, the environment in which they are used is always exposed to the sea surface, so the performance of rubber is significantly deteriorated by salt damage. In addition, since the ship is large, not only the load resistance but also the large number and volume of the fenders are required as the required characteristics of the fenders. For this reason, material cost becomes very expensive and initial installation cost is large. In addition, the service life is often not as long as 10 years, leading to an increase in maintenance costs.

As the fender, various types of cushioning functions are known, but among them, a thick solid fender made of an elastic material such as rubber has a simple structure, Because of its buffer function, it is hard to break and is widely used.

As solid-type fenders, various efforts have been made to devise the form and structure (Patent Documents 1 and 2). As a result, it has become possible to create an effect that further enhances the buffer function.

  Furthermore, improvements and efforts have been made with regard to specifications in cold regions, focusing on rubber composition, and rubber elastic materials with less temperature dependence have been developed using a mixture of natural rubber and other rubbers (patents) Reference 3). However, even with these more severe cold specifications, it has become possible to provide fenders with better mechanical properties.

The object of the present invention is to provide a rubber composition for a fender in a cold region, which is considered to be a particularly harsh environment. Further, it has superior elastic properties at low temperatures and a low fuel consumption effect that could not be achieved by the prior art. It is providing the rubber composition which shows this.

JP2000-303431 JP 10-176321 A JP2002-13121

Applying vulcanizable rubber, other terpolymers of linear rubber with a high cis structure and branched rubber with a high cis structure to lower the glass transition temperature and in cold regions The rubber composition for fenders having a low elastic modulus and excellent in fuel efficiency is provided. Furthermore, by using the rubber composition for a fender described above, a fender excellent in a solid type is provided.

The present invention is characterized in that it is a vulcanizable rubber (A), a linear rubber (B) having a high cis structure other than (A), and a branched rubber (C) having a high cis structure. The present invention relates to a rubber composition for a fender.

  The present invention also relates to the rubber composition for fenders described above, wherein the vulcanizable rubber (A) is natural rubber.

Further, according to the present invention, the linear rubber (B) having a high cis structure has a 1,4-cis structure of 80% or more, a 5% toluene solution viscosity (Tcp), and a Mooney viscosity (ML _{1 + 4 at} 100 ° C.). ) (Tcp / ML _{1 + 4} ) is 2.0 to 5.0, and relates to the rubber composition for fenders described above.

In the present invention, the branched rubber (C) having a high cis structure has a 1,4-cis structure of 80% or more, a 5% toluene solution viscosity (Tcp), and a Mooney viscosity at 100 ° C. (ML _{1 + 4} ). And the ratio (Tcp / ML _{1 + 4} ) is 0.5 to 2.0.

  The present invention also relates to a fender that uses the rubber composition for fenders described above.

  A rubber composition for fenders having a low glass transition temperature, a low elastic modulus even in a cold region, and excellent fuel efficiency, and a fender using the same.

(A) Vulcanizable rubber As vulcanizable rubber, natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber (IR), nitrile rubber (NBR), ethylene propylene Examples thereof include rubber (EPM), chloroprene rubber (CR), butyl rubber, urethane rubber, acrylic rubber, and silicon rubber.

  Of these, natural rubber (NR) is particularly desirable.

  The amount of (A) to be blended is 20 to 90 parts by weight, more preferably 30 to 80 parts by weight, particularly preferably 40 to 70 parts by weight of vulcanizable rubber in 100 parts by weight of the total rubber. What to mix | blend is preferable. When blended, it has various physical properties (tensile strength, elongation, tear strength, compression set, etc.) necessary for the compression characteristics of the fender and has sufficient rubber elasticity at low temperatures, which is characteristic of the present invention. Material can be obtained.

(B) Linear rubber having a high cis structure The linear rubber having a high cis structure is selected from rubbers other than those selected from the above-mentioned (A) vulcanizable rubber. The types include natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber (IR), nitrile rubber (NBR), ethylene propylene rubber (EPM), chloroprene rubber (CR), Examples include butyl rubber, urethane rubber, acrylic rubber, and silicon rubber.

  Of these, butadiene rubber (BR) is particularly desirable.

Furthermore, as a necessary condition for a linear rubber having a high cis structure, it is necessary to quantitatively define the following two structures.
(1) High cis structure That is, the rubber microstructure contains a cis structure, and the ratio is generally preferably 80% or more, more preferably 88.0% to 99.8%, and 96.0 to 99.0%. Is more preferable, and 95.0 to 98.9% is particularly preferable.
(2) Ratio (Tcp / ML _{1 + 4} ) of 5% toluene solution viscosity (Tcp), which is an index indicating the degree of branching of the linear structure molecule, and Mooney viscosity (ML _{1 + 4} ) at 100 ° C. is 2.0 to 5 0.0, more preferably 2.1 to 4.0, and particularly preferably 2.2 to 3.0.
Tcp indicates the degree of molecular entanglement in the concentrated solution. In the case of high cis rubber having the same molecular weight distribution, the degree of branching is the same if the molecular weight is the same (ie, ML _{1 + 4} is the same). (The larger Tcp, the smaller the branching degree). Moreover, (the larger Tcp / _{ML 1 + 4,} degree of branching is small) index when Tcp / _{ML 1 + 4} is for comparing the degree of branching of different height Shisugomu of _{ML 1 + 4} is used as a.
In other words, the larger the value of Tcp / ML _{1 + 4} , the more linear it is.

Further, the molecular weight distribution (Mw / Mn) is preferably 1.5 to 5.0, more preferably 2.0 to 4.0, and particularly preferably 2.2 to 3.0.
If the value of the molecular weight distribution is less than 1.5, the processability deteriorates, which is not preferable. On the other hand, if it is larger than 5.0, the destructive properties are adversely affected.

Furthermore, ML _{1 + 4} at 100 ° C. is preferably 30 to 60, more preferably 35 to 55, and particularly preferably 37 to 50. If it is smaller than this value, rubber properties such as fracture characteristics tend to be lowered, and if it is higher, workability is poor and it becomes difficult to knead with the compounding agent. Furthermore, it is required that the gel content is not substantially contained.

  The amount of (B) to be blended is preferably 3 to 90 parts by weight, more preferably 5 to 80 parts by weight, and particularly preferably 7 to 70 parts by weight based on 100 parts by weight of the total rubber. When blended, it has various physical properties (tensile strength, elongation, tear strength, compression set, etc.) necessary for the compression characteristics of the fender and has sufficient rubber elasticity at low temperatures, which is characteristic of the present invention. Material can be obtained.

(C) Branched rubber having a high cis structure The branched rubber having a high cis structure is selected from rubbers other than those selected from the above-mentioned (A) vulcanizable rubber. The types include natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber (IR), nitrile rubber (NBR), ethylene propylene rubber (EPM), chloroprene rubber (CR), Examples include butyl rubber, urethane rubber, acrylic rubber, and silicon rubber.

  Of these, butadiene rubber (BR) is particularly desirable.

Furthermore, the following two structures must be defined quantitatively as necessary conditions for a branched rubber having a high cis structure.
(1) High cis structure In other words, the rubber microstructure contains a cis structure, and the ratio is generally preferably 80% or more, more preferably 88.0% to 99.8%, and 96.0 to 99.0%. More preferably, 95.0 to 98.9% is particularly preferable.
(2) The ratio (Tcp / ML _{1 + 4} ) of 5% toluene solution viscosity (Tcp) and Mooney viscosity (ML _{1 + 4} ), which is an index indicating the degree of branching of the branched structure molecule, is preferably 0.5 to 2.0, More preferably, it is 0.7-1.8, Most preferably, it is 0.8-1.5.
Tcp indicates the degree of molecular entanglement in the concentrated solution. In the case of high cis rubber having the same molecular weight distribution, the degree of branching is the same if the molecular weight is the same (ie, ML _{1 + 4} is the same). (The larger Tcp, the smaller the branching degree). Moreover, (the larger Tcp / _{ML 1 + 4,} degree of branching is small) index when Tcp / _{ML 1 + 4} is for comparing the degree of branching of different height Shisugomu of _{ML 1 + 4} is used as a.
In other words, the smaller the value of Tcp / ML _{1 + 4} , the more branched.

If Tcp / ML _{1 + 4} is larger than the above range, the problem of low-temperature crystallization is likely to occur. Conversely, if Tcp / ML _{1 + 4} is smaller than the above range, the problem of deterioration in fracture characteristics is likely to occur.

  Further, the molecular weight distribution (Mw / Mn) is preferably 1.5 to 9.0, more preferably 2.0 to 5.0, and particularly preferably 2.5 to 4.0.

  If the value of the molecular weight distribution is less than 1.5, the processability deteriorates, which is not preferable. On the other hand, if it is larger than 9.0, it is not preferable because the destructive property is deteriorated.

Furthermore, ML _{1 + 4} at 100 ° C. is preferably 30 to 60, more preferably 35 to 55, and particularly preferably 37 to 50. If the value is smaller than this value, the physical properties of rubber such as fracture characteristics tend to be lowered. Furthermore, it is a requirement that the gel content is not substantially contained.

  The amount of (C) to be blended is preferably 3 to 90 parts by weight, more preferably 5 to 80 parts by weight, and particularly preferably 7 to 70 parts by weight based on 100 parts by weight of the total rubber. When blended, various physical properties (tensile strength, elongation, tear strength, compression set, etc.) necessary for compression characteristics are obtained, and sufficient rubber elastic material is obtained at a low temperature characteristic of the present invention. Can do.

  (A) A vulcanizable rubber, a linear rubber (B) having a high cis structure other than A, and a branched rubber (C) having a high cis structure are within a range in which the object of the present invention is not impaired. If desired, various chemicals usually used in the rubber industry, such as vulcanizing agents, vulcanization accelerators, process oils, anti-aging agents, anti-scorching agents, zinc white, and stearic acid can be contained.

Further, the rubber composition of the present invention is obtained by kneading using a kneader such as an open kneader such as a roll, a closed kneader such as a Banbury mixer, and vulcanized after molding. It can be applied to various rubber products.

All the examples of the present invention are compared with Comparative Example 1 which is a binary rubber configuration of (A) a vulcanizable rubber and a linear rubber having a high cis structure other than (A). It turns out that the elasticity modulus in 30 degreeC has fallen. Furthermore, it can be seen that the crystallization temperatures are all lower than in the comparative example.
Therefore, in the ternary rubber composition in which the rubber of the low cis structure of the present invention is blended, improvement in rubber elasticity at low temperature is seen, suggesting that an excellent rubber for fenders can be provided.

(Tensile modulus)
The tensile modulus M100 was measured according to JIS K6251. The index was calculated with a comparative example of 100. The larger the value, the higher the tensile stress.

(Molecular weight measurement)
The molecular weight and molecular weight distribution were calculated using a standard polystyrene calibration curve using two columns in series using HLC-8220 GPC manufactured by Tosoh Corporation. The column used was Shodex GPC KF-805L column, which was measured by measuring a column temperature of 40 ° C. in THF.

(Differential calorimeter (DSC)
The measurement was performed under a nitrogen atmosphere using a differential calorimeter (DSC). The temperature was raised from 30 ° C to 100 ° C at 10 ° C / min, held at 100 ° C for 10 minutes, and then immediately measured for crystallization from 100 ° C to -70 ° C at a rate of 5 ° C / min. did.

(Mooney viscosity measurement)
The Mooney viscosity (ML _{1 + 4} , 100 ° C.) measurement was performed in accordance with JIS K-6300 standard.

(Vulcanization speed)
The vulcanization speed was measured in accordance with JIS K-6300 standard, and the time required to reach 90% vulcanization degree was measured using JSR Clastometer 2F type.

[Vulcanized physical properties]
(hardness)
The hardness was measured according to a measurement method defined in JIS-K6253.

(Tensile stress)
Tensile stress measured 100% tensile stress according to JIS-K6251. The larger the value, the higher the tensile stress.

(Tensile strength)
For the tensile strength, the tensile strength at break was measured according to JIS-K6251. It shows that it is so favorable that a numerical value is large.

(Elongation at break)
The elongation at break was determined by measuring the elongation at break according to JIS-K6251. It shows that it is so favorable that a numerical value is large.

(Rebound resilience)
The rebound resilience was measured at 23 ° C. according to JIS-K6255. The larger the value, the better the resilience.

(Low fuel consumption (heat generation))
It measured according to the measuring method prescribed | regulated to JISK6265. PS (%) was shown as compression set at the time of dynamic change, and the temperature rise after 25 minutes at a start temperature of 100 ° C. was shown as ΔT. The index was calculated using a comparative example of 100. A larger index indicates better physical properties.

(Low fuel consumption of vulcanizate (tan δ))
Using an EPLEXOR 100N manufactured by GABO under the conditions of a temperature of 70 ° C., a frequency of 10 Hz, and a dynamic strain of 0.3%, Comparative Example 1 was set as 100 and indicated as an index. The larger the index, the better.

(Crystallization temperature)
The crystallization temperature was measured using an EPLEXOR 100N manufactured by GABO under the conditions of a temperature of −30 ° C., a frequency of 10 Hz, and a dynamic strain of 0.3%, and the rise in elastic modulus was obtained from the tangent line between two points. Using temperature, the lower the temperature compared to Comparative Example 1, the better.

(Low temperature storage modulus)
The low-temperature storage elastic modulus (E ′ @ − 30 ° C.) was measured by using EBO LEXOR 100N manufactured by GABO under the conditions of a temperature of −30 ° C., a frequency of 10 Hz, and a dynamic strain of 0.3%. The index is 100, and the larger the value, the lower the elastic modulus at −30 ° C. and the better.

(Rambourn wear evaluation)
Abrasion resistance: 4.5 kg load using a Lambourn Abrasion Tester, sand fall rate of about 15 g / min. The following slip ratio was tested. Slip rate: 20%, sample rotation speed 60 m / min. , Drum rotation speed 48 m / min. Slip rate: 60%, sample rotation speed 60 m / min, drum rotation speed 24 m / min. The amount of wear (cc / min) measured in (1) was obtained, and Comparative Example 1 was taken as 100 and evaluated by an index. The higher the index, the better the wear resistance.

Examples are shown below.
(Example)
Using the polybutadiene of Table 1, in accordance with the formulation shown in Table 2, using a 250 cc closed kneading machine, kneading natural rubber, linear polybutadiene, low cis BR, carbon black, etc., followed by vulcanization accelerator and sulfur Were mixed in an open roll. Next, press vulcanization was performed, and the physical properties were evaluated by the obtained vulcanized test pieces. The results are shown in Table 1.

(Comparative Example 1)
According to the formulation shown in Table 2, a natural rubber, linear polybutadiene, carbon black and the like were kneaded using a 250 cc closed kneading apparatus, and then the vulcanization accelerator and sulfur were mixed with an open roll. Next, press vulcanization was performed, and the physical properties were evaluated by the obtained vulcanized test pieces.
The results are shown in Table 1.

The materials applied in this experiment are as follows.
Natural rubber: RSS # 1 (ML1 + 4, 100 ° C = natural rubber adjusted to 70)
Linear high cis polybutadiene: UBEPOL BR150L manufactured by Ube Industries, Ltd.
Branched high cis polybutadiene: UBEPOL BR150B manufactured by Ube Industries, Ltd.
Carbon Black: Tokai Carbon Seast 9
Aroma oil: Esso Oil # 110
Stearic acid: Asahi Denka Adeka Fatty Acid SA-300
Zinc oxide: Sakai Chemical Industry Sazex No. 1 anti-aging agent: Era Ouchi Nocrack 6C
Vulcanization accelerator: Noxeller NS (N-tert-butyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Sulfur: Sulfur manufactured by Hosoi Chemical Co., Ltd.

Claims (5)

Vulcanizable rubber (A), linear rubber (B) having a high cis structure other than (A), and branched rubber (C) having a high cis structure Rubber composition.   2. The rubber composition for a fender according to claim 1, wherein the vulcanizable rubber (A) is natural rubber. The linear rubber (B) having a high cis structure has a 1,4-cis structure of 80% or more, and a ratio (Tcp) between 5% toluene solution viscosity (Tcp) and Mooney viscosity (ML _{1 + 4} ) at 100 ° C. / ML1 _{+ 4} ) is 2.0-5.0, The rubber composition for fenders in any one of Claim 1 and 2 characterized by the above-mentioned. The branched rubber (C) having a high cis structure has a 1,4-cis structure of 80% or more, a ratio of 5% toluene solution viscosity (Tcp) to Mooney viscosity (ML _{1 + 4} ) at 100 ° C. (Tcp / ML1 _{+ 4} ) is 0.5-2.0, The rubber composition for fenders in any one of Claims 1-3 characterized by the above-mentioned.   An anti-mold material comprising the rubber composition for an anti-mold material according to claim 1.