JPWO2011114990A1 - Rubber composition, cross-linked rubber composition, and highly attenuated laminate - Google Patents

Abstract

An object of the present invention is to provide a rubber composition or a crosslinked rubber composition capable of achieving both improvement in damping performance or grip performance and rigidity, and a high-damping laminate using at least one of them. 100 parts by mass of two or more crosslinkable rubber components, 10 to 100 parts by mass of an inorganic filler having a silanol group, 0.1 to 30 parts by mass of a polylactic acid resin, and 0.1 to 10 parts of polypropylene A rubber composition containing parts by mass, a crosslinked rubber composition containing a crosslinked rubber and polypropylene obtained by crosslinking the rubber composition, and the rubber composition or the crosslinked rubber composition and a hard plate A high attenuation laminate obtained by alternately laminating and is provided.

Description

  The present invention relates to a rubber composition, a crosslinked rubber composition, and a high damping laminate.

In recent years, anti-vibration devices, vibration isolation devices, seismic isolation devices, and the like are rapidly spreading as vibration energy absorbing devices. In such an apparatus, a rubber composition having vibration energy damping performance is used.
For example, laminated rubber for seismic isolation used in bridge bearings and building seismic isolation devices has high damping (attenuates vibration energy by converting vibration into more heat) and has a desired rigidity. It is required to be expressed.
As a rubber composition used for such a seismic isolation laminated rubber, the present applicant described in Patent Document 1 “100 parts by mass of a diene rubber, 40 to 75 parts by mass of carbon black, and 5 to 35 parts by mass of silica. , A rubber composition for a high attenuation laminate including 5 to 55 parts by mass of an inorganic filler and 5 to 50 parts by mass of a petroleum resin.

  On the other hand, with respect to the formation of polypropylene fibrils randomly dispersed in a vulcanized diene-containing rubber matrix, a vulcanized rubber comprising a vulcanized diene-containing rubber in which polypropylene fibrils are randomly dispersed. In the matrix, the polypropylene fibrils form a blend of (1) (a) a polymer alloy containing polypropylene and (b) an unvulcanized rubber material, wherein the polypropylene is in the blend from about 5 to about Present in an amount in the range of 25 phr; and (2) vulcanizing the rubber stock in the blend after orienting the polypropylene by applying heat and flowing the rubber stock through a molding cavity Thus, the vulcanized rubber matrix formed on the spot is proposed (patented) Document 2).

JP 2006-143849 A JP 7-90129 A

However, the inventors of the present application have found that, when the conventional rubber composition for a high-damping laminate is improved in its damping property, its rigidity is lowered and the composition becomes soft.
Accordingly, the present invention provides a rubber composition or a crosslinked rubber composition for a highly attenuated laminate that can achieve both improvement in damping properties and rigidity, and a highly attenuated laminate using at least one of these. For the purpose.

As a result of intensive studies to solve the above-mentioned problems, the present inventor formulated a specific amount of an inorganic filler having a silanol group, a polylactic acid resin, and polypropylene with respect to two or more types of crosslinkable rubber components. It has been found that a rubber composition and a crosslinked rubber composition obtained by crosslinking the rubber composition can achieve both improvement in damping property and rigidity.
The inventor of the present application also provides a rubber composition in which a specific amount of an inorganic filler having a silanol group, a polylactic acid resin, and polypropylene are blended with two or more kinds of crosslinkable rubber components, and a crosslinked rubber obtained by crosslinking the rubber composition. The present inventors have found that the composition can simultaneously improve the grip performance and rigidity of the tire, and have completed the present invention.
That is, this invention provides the following 1-18.

1. 100 parts by mass of two or more kinds of crosslinkable rubber components, 10-100 parts by mass of an inorganic filler having a silanol group, 0.1-30 parts by mass of a polylactic acid resin, and 0.1-10 parts by mass of polypropylene, Containing a rubber composition.
2. 2. The rubber composition as described in 1 above, wherein the rubber component is a diene rubber.
3. The rubber composition according to 1 or 2 above, wherein the rubber component includes rubber A and rubber B, and the rubber A and the rubber B are incompatible.
4). The rubber component includes rubber A and rubber B, the rubber A is at least one selected from the group consisting of natural rubber and polyisoprene, and the rubber B is selected from the group consisting of polybutadiene and a butadiene copolymer. 4. The rubber composition according to any one of the above 1 to 3, which is at least one kind.
5. 5. The rubber composition as described in 3 or 4 above, wherein a mass ratio of the rubber A and the rubber B (rubber A / rubber B) is 90/10 to 10/90.
6). 6. The rubber composition according to any one of 1 to 5, further containing 5 to 50 parts by mass of a petroleum resin with respect to 100 parts by mass of the rubber component.
7). 7. The rubber composition according to any one of 1 to 6 above, further containing 5 to 55 parts by mass of an inorganic filler other than the inorganic filler having a silanol group with respect to 100 parts by mass of the rubber component.
8). 8. The rubber composition according to any one of 1 to 7, wherein the polylactic acid resin has a melting point of 180 ° C. or lower.
9. The rubber composition according to any one of 1 to 8 above, wherein the polylactic acid resin has a number average molecular weight of 1,000 to 200,000.
10. Any one of 1 to 9 above, wherein a mass ratio of the inorganic filler having a silanol group and the polylactic acid resin (inorganic filler having a silanol group / polylactic acid resin) is 1/1 to 10/1. The rubber composition as described in 2.
11. Furthermore, the rubber composition in any one of said 1-10 which contains carbon black and the quantity of the said carbon black is 10-90 mass parts with respect to 100 mass parts of said rubber components.
12 Furthermore, the rubber composition in any one of said 1-11 which contains a silane coupling agent and the quantity of the said silane coupling agent is 1-10 mass parts with respect to 100 mass parts of inorganic fillers which have the said silanol group. object.
13. The rubber composition according to any one of 3 to 12, wherein the polypropylene forms a continuous phase in the rubber component.
14 A crosslinked rubber composition containing a crosslinked rubber, obtained by crosslinking the rubber composition according to any one of 1 to 13 above.
15. A rubber composition for a high attenuation laminate, wherein the rubber composition according to any one of 1 to 13 or the crosslinked rubber composition according to 14 is used for a high attenuation laminate.
16. A rubber composition for a pneumatic tire, wherein the rubber composition according to any one of 1 to 13 or the crosslinked rubber composition according to 14 is used for a pneumatic tire.
17. 16. A high attenuation laminate obtained by alternately laminating the rubber composition for a high attenuation laminate according to 15 and a hard plate.
18. A pneumatic tire formed using the rubber composition for a pneumatic tire described in 16 above.

The rubber composition of the present invention and the crosslinked rubber composition of the present invention can achieve both improvement in damping property or grip performance and rigidity.
The highly attenuated laminate of the present invention has both excellent attenuation and excellent rigidity.
The pneumatic tire of the present invention combines excellent grip performance and excellent rigidity.
In the present specification, the rigidity of the high-damping laminate and the rigidity of the tire are the same in the sense that they are difficult to deform.

FIG. 1 is a schematic cross-sectional view of a highly attenuated laminate that represents an example of an embodiment of the laminate of the present invention. FIG. 2 is a schematic side view of a sample for a lap shear type shear test. FIG. 3 is a graph showing an example of a hysteresis curve obtained by a lap shear type shear test. FIG. 4 is a graph showing the relationship between damping property and rigidity obtained in the example of the present invention. FIG. 5 is a cross-sectional view of a rubber composition schematically showing an example of the morphology that the rubber composition of the present invention can have. FIG. 6 is a photograph of one example of the morphology of the rubber composition of the present invention observed with a scanning probe microscope (SMP).

The present invention is described in detail below.
The rubber composition of the present invention comprises two or more kinds of crosslinkable rubber components 100 parts by mass, 10 to 100 parts by mass of an inorganic filler having a silanol group, 0.1 to 30 parts by mass of a polylactic acid resin, and polypropylene. It is a rubber composition containing 0.1-10 mass parts.
In the present specification, the rubber composition of the present invention can be used as a rubber composition for a high-damping laminate and a rubber composition for a pneumatic tire.

<Crosslinkable rubber component>
The rubber component contained in the rubber composition of the present invention is not particularly limited as long as it is a rubber component that can be crosslinked with a sulfur compound or a peroxide. Specific examples thereof include a diene rubber and a heat having a double bond. Examples thereof include a plastic elastomer.

Specific examples of the diene rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), vinyl-cis butadiene rubber (VCR), and styrene-butadiene copolymer rubber (SBR). ), Acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR) and the like.
Specific examples of the thermoplastic elastomer having a double bond include ethylene-propylene-diene rubber (EPDM), styrene-butadiene-styrene block copolymer (SBS), and hydrogenation (hydrogenation) thereof. Product (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-isoprene-styrene block copolymer (SIS), styrene-isobutylene-styrene block copolymer (SIBS), and the like.

  In the present invention, among these crosslinkable rubber components, the resulting rubber composition of the present invention has good physical properties such as tensile strength after vulcanization and elongation at break, and the rubber composition of the present invention. In the high attenuation laminate of the present invention (hereinafter also referred to as “laminate of the present invention”) obtained by alternately laminating and hard plates, a rubber composition and a hard plate (for example, general structural steel plate, A diene rubber is preferred because it has good adhesion to a hot rolled steel sheet and the like and is excellent in repeated deformation as a pneumatic tire.

In the present invention, two or more types of crosslinkable rubber components can be used as a rubber component containing two or more types of crosslinkable rubber. As one of preferred embodiments of the present invention, a case where the rubber component contains rubber A and rubber B can be mentioned.
And it is preferable that rubber | gum A and rubber | gum B are incompatible from a viewpoint that the improvement of damping property or grip performance and rigidity can be made to make compatible further.

Examples of the rubber A include at least one selected from the group consisting of natural rubber and polyisoprene.
Examples of the rubber B include at least one selected from the group consisting of polybutadiene and butadiene copolymers. Examples of the butadiene copolymer include styrene butadiene copolymer and vinyl-cis butadiene rubber.

  The mass ratio of rubber A and rubber B (rubber A / rubber B) can improve both damping performance and grip performance and rigidity, and can ensure rigidity with a small amount of polypropylene and durability. From the viewpoint of superiority, it is preferably 90/10 to 10/90, and more preferably 70/30 to 30/70.

Among these, it is preferable that the rubber A contains natural rubber and the rubber B contains vinyl-cis butadiene rubber from the viewpoint that both improvement in damping property and rigidity can be achieved and the damping property at low temperature is excellent. .
Further, from the viewpoint that both the improvement of the damping property and the rigidity can be achieved and the damping property at a low temperature is excellent, when the rubber A is a natural rubber and the rubber B is a vinyl-cisbutadiene rubber, The mass ratio with the rubber B (rubber A / rubber B) is preferably 90/10 to 10/90, and more preferably 70/30 to 70/90, from the viewpoint that both the damping property and the rigidity can be improved. More preferably, it is 30/70.

Here, vinyl - and cis-butadiene rubber, in an inert organic solvent mainly composed of C ₄ fraction, polybutadiene rubber composite comprising the cis-1,4 polymerization and syndiotactic-1,2 polymerization It is.
Specific examples of the vinyl-cis butadiene rubber include, for example, 97 to 80% by mass of cis-1,4-polybutadiene rubber having a cis 1,4-bond content of 90% or more, and syndiotactic-1,2-polybutadiene. Examples include composites composed of 3 to 20% by mass.

  In the present invention, as such a vinyl-cis butadiene rubber, for example, a commercially available product such as UBEPOL-VCR manufactured by Ube Industries, Ltd. can be used.

In addition, for the combination of rubber A and rubber B, rubber A contains natural rubber, and rubber B can be improved in both grip performance and rigidity, and excellent in grip performance at low temperatures. It preferably contains a styrene butadiene copolymer.
In addition, from the viewpoint that the improvement in grip performance and rigidity can be achieved at the same time and the grip performance at low temperature is excellent, when rubber A is natural rubber and rubber B is a styrene butadiene copolymer, The mass ratio with the rubber B (rubber A / rubber B) is preferably 20/80 to 80/20, more preferably 30/70 to 80/20 from the viewpoint that both improvement in grip performance and rigidity can be achieved. More preferably, it is 70/30.

  The styrene butadiene copolymer preferably has a styrene content of 5 to 40% by weight and more preferably 5 to 30% by weight from the viewpoint that both improvement in grip performance and rigidity can be achieved. .

<Inorganic filler having silanol group (silanol group-containing inorganic filler)>
The inorganic filler having a silanol group contained in the rubber composition of the present invention is not particularly limited as long as it is an inorganic filler having a silanol group (Si—OH) on at least a part of the surface.
Examples of the inorganic filler having a silanol group include silica, clay, talc and the like, and these may be used alone or in combination of two or more.

Specific examples of silica include fumed silica, calcined silica, precipitated silica, pulverized silica, fused silica, and colloidal silica.
Silica preferably has an average aggregate particle diameter of 5 to 50 μm, more preferably 5 to 30 μm.
The BET specific surface area of silica is preferably 50 to 300 m ² / g from the viewpoints of reinforcement and high damping properties and excellent tire grip.

  The clay is not particularly limited as long as it is a white powder product that is industrially purified from natural ore containing hydrous aluminum silicate as a main component. Specific examples of the clay include T-clay, kaolin clay, wax stone clay, sericite clay, calcined clay, and silane-modified clay. Further, for example, those forming an aggregate of fine particles of clay minerals such as pyrophyllite, kaolinite, halloysite, sericite, montmorillonite can be used. In addition, aggregates of quartz and kaolinite, diatomaceous earth, and the like can be used.

  When silica and clay are used in combination as the silanol group-containing inorganic filler, the amount ratio of silica and clay is 25 to 150 parts by mass with respect to 100 parts by mass of silica from the viewpoint of excellent mixing. It is preferable that it is 25 to 100 parts by mass.

In the present invention, the content of the inorganic filler having a silanol group is 10 to 100 parts by mass with respect to 100 parts by mass of the two or more types of crosslinkable rubber components described above. From the standpoint of improving durability and low temperature performance (for example, damping property and grip performance at low temperature), it is more preferably 10 to 90 parts by mass, and more preferably 10 to 80 parts by mass. More preferably, it is part.
When the rubber composition of the present invention is used for a high-damping laminate, the content of the inorganic filler having a silanol group can achieve both improvement in damping property and rigidity, and durability and low-temperature performance ( For example, from the viewpoint of excellent attenuation at low temperatures, the amount is preferably 10 to 60 parts by mass, and preferably 15 to 50 parts by mass with respect to 100 parts by mass of the two or more cross-linkable rubber components described above. More preferably, it is 20-40 mass parts.
When the rubber composition of the present invention is used for a pneumatic tire, the content of the inorganic filler having a silanol group can achieve both improvement in grip performance and rigidity, durability and low temperature performance (for example, From the viewpoint of excellent grip performance at low temperature), it is preferably 20 to 90 parts by weight, more preferably 20 to 80 parts by weight, based on 100 parts by weight of two or more kinds of crosslinkable rubber components. More preferably, it is 30-70 mass parts.

<Polylactic acid resin>
The polylactic acid resin contained in the rubber composition of the present invention is a homopolymer of lactic acid and / or a copolymer of lactic acid.
Here, the homopolymer of lactic acid is polylactic acid.
The lactic acid copolymer is a copolymer of lactic acid and one kind of monomer selected from the group consisting of hydroxy acids other than lactic acid, lactones and diene compounds copolymerizable with lactic acid.

Specific examples of hydroxy acids other than lactic acid include hydroxyacetic acid (glycolic acid), hydroxybutyric acid, malic acid, citric acid, ricinoleic acid, shikimic acid, salicylic acid, and coumaric acid.
Specific examples of the lactone include ε-caprolactone, α-methyl-ε-caprolactone, ε-methyl-ε-caprolactone, γ-valerolactone, δ-valerolactone, β-butyrolactone, γ-butyrolactone, β -Propiolactone and the like are exemplified.
Specific examples of the diene compound copolymerizable with lactic acid include butadiene and isoprene.
The copolymer of these and lactic acid may be a block copolymer, a random block copolymer, a random copolymer, or a graft polymer as long as lactic acid is a main component. Preferably there is.

In the present invention, among such polylactic acid-based resins, the resulting rubber composition of the present invention has excellent melting properties, such as tensile strength after vulcanization, elongation at break, etc., so that the melting point is 180 ° C. or less. However, it is preferably 160 ° C. or lower, and more preferably 135 ° C. or lower.
For the same reason, the number average molecular weight is preferably 1,000 to 200,000, more preferably 1,000 to 100,000.
Here, the melting point is a value measured at a heating rate of 10 ° C./min by differential scanning calorimetry (DSC-Differential Scanning Calorimetry).
The number average molecular weight is a number average molecular weight (polystyrene conversion) measured by gel permeation chromatography (GPC). Tetrahydrofuran (THF), N, N-dimethylformamide (DMF) is used for measurement. ), Chloroform is preferably used as a solvent.

  Moreover, in this invention, content of the said polylactic acid-type resin is 0.1-30 mass parts with respect to 100 mass parts of 2 or more types of crosslinkable rubber components mentioned above, and it has damping property or grip performance. From the standpoint that both improvement in rigidity can be achieved and excellent durability, the amount is more preferably 1 to 20 parts by mass, and further preferably 3 to 15 parts by mass.

  Furthermore, in the present invention, as such a polylactic acid resin, for example, LACEA H-440 (melting point: 155 ° C., number average molecular weight: 78000, weight average molecular weight: 150,000) manufactured by Mitsui Chemicals, Shimadzu Corporation Commercially available products such as Lacti # 1012 (melting point: 170 ° C., number average molecular weight: 180000) can be used.

In the present invention, by containing the above-described inorganic filler having a silanol group and a polylactic acid resin within the above-described content range, the rubber composition of the present invention obtained is excellent in processability, The laminate of the invention has a high damping property, and the rubber obtained using the rubber composition of the invention has excellent grip performance and good rigidity.
Although the detailed mechanism is unknown, the inorganic filler having a silanol group forms a crosslink by a siloxane bond, and due to the interaction between the remaining silanol group or the siloxane bond and the ester bond of the polylactic acid resin, This is probably because the polylactic acid resin collects around the crosslinked filler and crystallizes.

In the present invention, the processability of the resulting rubber composition of the present invention becomes better, the damping property of the laminate of the present invention is higher, and the rubber obtained using the rubber composition of the present invention has grip performance. The mass ratio between the inorganic filler having a silanol group and the polylactic acid resin (silanol group-containing inorganic filler / polylactic acid resin) is 1/1 to 10 because / 1 is preferred.
Further, in the present invention, when the rubber composition of the present invention is used for a high attenuation laminate, the processability of the resulting rubber composition of the present invention becomes better, and the attenuation of the laminate of the present invention is also improved. Is higher and the rigidity is better, the mass ratio (silanol group-containing inorganic filler / polylactic acid resin) of the inorganic filler having a silanol group and the polylactic acid resin described above is 1/1 to It is preferably 10/1, and more preferably 8/1 to 4/1.
In the present invention, when the rubber composition of the present invention is used for a pneumatic tire, the processability of the resulting rubber composition of the present invention becomes better, and the rubber composition of the present invention is used. Because the resulting rubber has excellent grip performance and better rigidity, the mass ratio of the above-mentioned inorganic filler having a silanol group to the polylactic acid resin (silanol group-containing inorganic filler / polylactic acid resin) is 1/1 to 8/1 is preferable, and 2/1 to 7/1 is more preferable.

<Polypropylene>
The polypropylene contained in the rubber composition of the present invention (for example, for high damping laminates, pneumatic tires, etc.) is not particularly limited as long as it is a homopolymer or copolymer obtained from a monomer containing propylene. For example, a conventionally well-known thing is mentioned.
Of these, a propylene homopolymer and a polypropylene copolymer containing 50 mol% or more of a propylene monomer are preferable from the viewpoint of being able to achieve both improvement in damping property or grip performance and rigidity, and excellent durability.
Polypropylene is not particularly limited for its production. For example, a conventionally well-known thing is mentioned. Polypropylenes can be used alone or in combination of two or more.

In this invention, the quantity of a polypropylene is 0.1-10 mass parts with respect to 100 mass parts of 2 or more types of crosslinkable rubber components. In such a range, it is possible to achieve both improvement in damping performance or grip performance and rigidity, satisfy high breaking elongation required for a rubber composition for a high damping laminate, and excellent durability. . When the amount of polypropylene exceeds 10 parts by mass with respect to 100 parts by mass of the rubber component, the horizontal rigidity is increased, but the damping property or grip performance is not improved so much, and is required for a rubber composition for a high attenuation laminate. Thus, the elongation at break of 550% or more cannot be obtained, and it tends to break before exhibiting high damping performance or to be fatigued during repeated deformation.
The amount of the polypropylene is 0.5 to 8 with respect to 100 parts by mass of the rubber component from the viewpoint that it is possible to further improve the damping property or the grip performance and the rigidity, and is excellent in durability and high in elongation at break. It is preferable that it is a mass part, and it is more preferable that it is 1-5 mass parts.

<Petroleum resin>
The rubber composition of the present invention preferably contains a petroleum resin from the viewpoint of improving physical properties such as tensile strength after vulcanization and elongation at break and improving the damping property of the laminate of the present invention. preferable.
As the petroleum resin, conventionally known ones can be used, for example, C5 aliphatic unsaturated hydrocarbon polymer, C9 aromatic unsaturated hydrocarbon polymer, C5 aliphatic unsaturated polymer. Copolymers of saturated hydrocarbons and C9 aromatic unsaturated hydrocarbons can be used.

Specific examples of the C5 aliphatic unsaturated hydrocarbon include, for example, 1-pentene, 2-pentene, 2-methyl-1-butene contained in a C5 fraction obtained by thermal decomposition of naphtha, Olefinic hydrocarbons such as 3-methyl-1-butene and 2-methyl-2-butene; 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, 3-methyl-1 , 2-olefin hydrocarbons such as 2-butadiene;
These can be polymerized or copolymerized in the presence of a suitable catalyst. Here, the C5 aliphatic unsaturated hydrocarbon polymer is a co-polymer of a single C5 aliphatic unsaturated hydrocarbon homopolymer and two or more C5 aliphatic unsaturated hydrocarbons. It refers to any polymer.

Specific examples of the C9 aromatic unsaturated hydrocarbon include, for example, α-methylstyrene, o-vinyltoluene, m-vinyltoluene, p contained in a C9 fraction obtained by thermal decomposition of naphtha. -Vinyl-substituted aromatic hydrocarbons such as vinyltoluene.
These can be polymerized or copolymerized in the presence of a suitable catalyst. Here, the C9 aromatic unsaturated hydrocarbon polymer is a co-polymer of a single C9 aromatic unsaturated hydrocarbon homopolymer and two or more C9 aromatic unsaturated hydrocarbons. It refers to any polymer.

In addition, a copolymer of a C5 aliphatic unsaturated hydrocarbon and a C9 aromatic unsaturated hydrocarbon is a C9 aromatic unsaturated hydrocarbon in that the softening point of the copolymer is high. What a unit is 60 mol% or more is preferable, and what is 90 mol% or more is more preferable.
A copolymer of a C5 aliphatic unsaturated hydrocarbon and a C9 aromatic unsaturated hydrocarbon can be copolymerized in the presence of a suitable catalyst.

  The petroleum resin affects the physical properties of the aforementioned crosslinkable rubber component (particularly diene rubber) because its molecular weight and double bond reactivity have an effect, so the softening point (JIS K2207) is 100 ° C. or higher. The thing of 120 degreeC or more is more preferable.

  In the present invention, the content in the case of containing a petroleum resin as desired makes the physical properties such as tensile strength after vulcanization and elongation at break good, and the viewpoint of increasing the damping property of the laminate of the present invention. Therefore, the amount is preferably 5 to 50 parts by mass, and more preferably 10 to 45 parts by mass with respect to 100 parts by mass of the crosslinkable rubber component described above.

<Inorganic filler>
The rubber composition of the present invention has a higher damping property of the laminate of the present invention, more excellent grip performance of rubber obtained by using the rubber composition of the present invention, and from the viewpoint of better rigidity. It is preferable to further contain an inorganic filler other than the inorganic filler having a silanol group described above.
Specific examples of such inorganic fillers include calcium carbonate, heavy calcium carbonate, magnesium carbonate, aluminum hydroxide, and barium sulfate.

  In the present invention, among these inorganic fillers, they are calcium carbonate and heavy calcium carbonate because they can maintain particularly high damping properties and stability against long-term shear deformation and improve workability. Is preferred.

  In the present invention, when an inorganic filler other than the inorganic filler having a silanol group is optionally contained, the content of the inorganic filler other than the inorganic filler having a silanol group is determined by the attenuation of the laminate of the present invention. From the viewpoint of making the grip performance of the rubber obtained using the rubber composition of the present invention higher, and improving the rigidity, the amount of the crosslinkable rubber component described above is 5 to 100 parts by mass. The amount is preferably 55 parts by mass, more preferably 10 to 50 parts by mass, and still more preferably 15 to 40 parts by mass.

  In the present invention, the total amount of the inorganic filler having a silanol group and the inorganic filler other than the inorganic filler having a silanol group is higher in the attenuation of the laminate of the present invention, and the rubber composition of the present invention. From the viewpoint of improving the grip performance of the rubber obtained using the product and improving the rigidity, it is preferably 20 to 75 parts by mass with respect to 100 parts by mass of the crosslinkable rubber component described above. 30 to 65 parts by mass is more preferable. When the total amount is in such a range, the rubber composition with a good balance (high damping laminate) that has higher damping performance and grip performance, and more stable damping performance and rigidity against long-term repeated shear deformation. For body and pneumatic tire).

  The mass ratio of the inorganic filler having a silanol group and the inorganic filler other than the inorganic filler having a silanol group (inorganic filler having a silanol group / inorganic filler other than an inorganic filler having a silanol group) is: The ratio is preferably 1/1 to 1 / 2.5, more preferably 1/1 to 1 / 2.0. When the mass ratio is within this range, good workability can be obtained.

<Carbon black>
The rubber composition of the present invention has good physical properties such as tensile strength after vulcanization and elongation at break, higher damping properties of the laminate of the present invention, and the rubber composition obtained using the rubber composition of the present invention. From the viewpoint of improving grip performance and improving rigidity, it is preferable to further contain carbon black.

In the present invention, carbon black having a CTAB adsorption specific surface area of 100 m ² / g or more is preferably used, and carbon black of 110 to 370 m ² / g is more preferably used.
When the CTAB adsorption specific surface area is in the range of 100 m ² / g or more, the damping property of the obtained laminate of the present invention can be maintained higher, and the grip performance of the rubber obtained by using the rubber composition of the present invention. Can be made more excellent.
Here, the CTAB adsorption specific surface area is a value obtained by measuring the surface area that carbon black can be used for adsorption with rubber molecules by adsorption of CTAB (cetyltrimethylammonium bromide).
Examples of such carbon black include SAF, ISAF, and HAF. The CATB adsorption specific surface area can be measured by the method described in ASTM D3765-80.

In the present invention, it is possible to maintain the damping property of the laminate of the present invention higher, and to improve the grip performance of the rubber obtained using the rubber composition of the present invention. from the viewpoint, (specific surface area by nitrogen adsorption method) N ₂ AB of the carbon black is preferably a 110~370m ² / g, and more preferably 150~350m ² / g.
Examples of such carbon black include SAF class, ISAF class, and HAF class carbon blacks.

Further, in the present invention, when carbon black is optionally contained, the carbon black content can maintain the damping property of the obtained laminate of the present invention higher, and the rubber composition of the present invention is used. From the viewpoint that the grip performance of the rubber obtained can be made more excellent, it is preferably 10 to 90 parts by mass, and 10 to 75 parts by mass with respect to 100 parts by mass of the crosslinkable rubber component described above. Part is more preferable, and 20 to 75 parts by mass is even more preferable.
In the present invention, when carbon black is optionally contained, the content of the carbon black can be crosslinked as described above from the viewpoint that the resulting laminate of the present invention can maintain a higher attenuation. The amount is preferably 10 to 90 parts by mass, more preferably 10 to 75 parts by mass, and still more preferably 20 to 75 parts by mass with respect to 100 parts by mass of the rubber component.
Further, in the present invention, when carbon black is optionally contained, the content of the carbon black is a viewpoint that the grip performance of the rubber obtained using the rubber composition of the present invention can be further improved. Therefore, the amount is preferably 10 to 90 parts by weight, more preferably 10 to 75 parts by weight, and still more preferably 20 to 75 parts by weight with respect to 100 parts by weight of the crosslinkable rubber component. .

<Metal compound>
The rubber composition of the present invention promotes the decomposition (hydrolysis) of the polylactic acid-based resin described above, and increases the number of sites where the polylactic acid-based resin and the inorganic filler having a silanol group interact with each other. It is preferable to contain.
As said metal compound, a zinc compound, an aluminum compound, a copper compound etc. are mentioned, for example.
Of these, zinc compounds are preferable, and specifically zinc oxide, organic zinc phosphate, and fatty acid zinc are more preferable. Of these, zinc oxide is more preferable.

  In the present invention, the content in the case of containing a metal compound as desired is 0 with respect to 100 parts by mass of the crosslinkable rubber component described above from the viewpoint of excellent dispersion of the metal compound and mechanical strength of the crosslinked product. It is preferable that it is 1-10 mass parts, and it is more preferable that it is 0.1-3 mass parts.

<Silane coupling agent>
The rubber composition of the present invention preferably contains a silane coupling agent from the viewpoint of improving physical properties such as tensile strength after vulcanization and elongation at break of the rubber composition of the present invention to be obtained.
Specific examples of the silane coupling agent include bis- [3- (triethoxysilyl) -propyl] tetrasulfide, bis- [3- (trimethoxysilyl) -propyl] tetrasulfide, and bis- [ 3- (triethoxysilyl) -propyl] disulfide, mercaptopropyl-trimethoxysilane, mercaptopropyl-triethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercapto Benzothiazole tetrasulfide, triethoxysilylpropyl-methacrylate-monosulfide, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl-tetrasulfide and the like may be mentioned, and these may be used alone. It may be used in combination with more species.

In the present invention, when a silane coupling agent is optionally contained, the content of the silane coupling agent is 0.1 of the content of the inorganic filler having a silanol group described above from the viewpoint of excellent mechanical strength. It is preferable that it is 10 mass%, and it is more preferable that it is 1-8 mass%.
Further, when the rubber composition of the present invention is used as a rubber composition for a pneumatic tire, the content of the silane coupling agent is an inorganic material having a silanol group described above from the viewpoint of excellent balance between grip performance and rolling resistance. The content of the filler is preferably 0.1 to 10% by mass, and more preferably 1 to 8% by mass. The amount of the silane coupling agent can be 5% by mass or more of the silanol group-containing inorganic filler.

<Other additives>
The rubber composition of the present invention can contain other additives as necessary within a range not impairing the object of the present invention.
Examples of the additive include a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a plasticizer, a softening agent, a vulcanization aid, a flame retardant, a weathering agent, and a heat resistance agent. The rubber composition of this invention can contain the additive which the rubber composition for high attenuation | damping laminated bodies and the rubber composition for pneumatic tires can contain generally, for example.
Specific examples of the vulcanizing agent include sulfur; organic sulfur-containing compounds such as TMTD; organic peroxides such as dicumyl peroxide; and the like.
Specific examples of the vulcanization accelerator include sulfenamides such as N-cyclohexyl-2-benzothiazole sulfenamide (CBS); thiazoles such as mercaptobenzothiazole; tetramethylthiuram monosulfide and the like. Thiurams; stearic acid; and the like.
Specific examples of the antiaging agent include ketone / amine condensates such as TMDQ; amines such as DNPD; monophenols such as styrenated phenol; and the like.
Specific examples of the plasticizer include phthalic acid derivatives (for example, DBP, DOP and the like), sebacic acid derivatives (for example, DBS and the like) monoesters, and the like.
Specific examples of the softening agent include paraffinic oil (process oil), aroma oil, stearic acid, and wax.

  The method for producing the rubber composition of the present invention is not particularly limited. For example, a method of producing a rubber composition (for a high-attenuation laminate or for a pneumatic tire) by kneading an unvulcanized rubber composition containing at least the above-described essential components can be mentioned. Further, for example, an unvulcanized rubber composition containing the above-described components can be prepared by kneading using a known method and apparatus (for example, a Banbury mixer, a kneader, a roll, etc.).

The vulcanization conditions (primary crosslinking) of the rubber composition of the present invention are not particularly limited, and vulcanization can be performed under conventionally known vulcanization conditions using a sulfur compound or a peroxide.
In the present invention, the primary crosslinking temperature is preferably 130 to 200 ° C. from the viewpoint of being more excellent in rigidity (for example, horizontal rigidity).

In the present invention, it is preferable to heat-treat the rubber composition of the present invention that has undergone primary crosslinking.
The temperature condition of the heat treatment is not particularly limited as long as it is the same temperature as the primary crosslinking temperature, but is preferably in the range of a temperature 10 ° C. to 10 ° C. higher than the temperature of the primary crosslinking. More preferably, the temperature is in the range of 5 ° C. to 5 ° C., more preferably in the range of 2 ° C. to 2 ° C. higher than the temperature of primary crosslinking.

The heat treatment time is obtained from a vulcanization curve obtained from a rheometer torque defined in JIS K6300-2: 2001 using the rubber composition of the present invention before primary crosslinking (unvulcanized). Is preferably 0.5 to 3 times, more preferably 0.5 to 2 times.
Here, the vulcanization curve is based on JIS K6300-2: 2001 “How to obtain vulcanization characteristics by vibration vulcanization tester”, using a rotorless vulcanization tester as a rheometer at a predetermined test temperature. The obtained torque is on the vertical axis and the vulcanization time is on the horizontal axis. The rheometer test temperature is the above-described primary crosslinking temperature.
In such a vulcanization curve, when the torque is clear that you have reached the maximum value M _H from the minimum value M _L is required vulcanized start until the torque reaches 95% of the width of the minimum and maximum values The vulcanization time is T95.
When the torque continues to increase as the vulcanization time elapses and does not show a clear maximum value _MH , JIS K6300-2: 2001 states that “the vulcanization curve continues to rise and the vulcanization curve has a stable slope. Therefore, in the present invention, t _c (max) = 30 minutes from the time listed as the specific time, and the torque at that time is expressed as _MH . To do.

  By performing such heat treatment, the damping property of the laminate of the present invention can be further improved, and excellent vibration damping properties can be secured in a wide temperature range, which is obtained using the rubber composition of the present invention. The grip performance of the obtained rubber can be made more excellent. This is because the polylactic acid-based resin described above is decomposed (hydrolyzed) during vulcanization, for example, by moisture in the system, so that the polylactic acid-based resin after decomposition and an inorganic filler having a silanol group interact with each other. It is thought that it can be done.

The morphology of the rubber composition of the present invention (for example, for high-attenuation laminates and pneumatic tires) will be described below with reference to the accompanying drawings.
In the present invention, polypropylene has a continuous phase in the rubber component (especially when rubber A and rubber B are incompatible with each other) from the viewpoint that both the damping property and the improvement in grip performance and rigidity can be achieved. One preferred embodiment is to form a network.
FIG. 5 is a cross-sectional view of a rubber composition schematically showing an example of the morphology that the rubber composition of the present invention (for example, for a high-damping laminate and for a pneumatic tire) can have.
In FIG. 5, the rubber composition 100 of the present invention has rubber A (reference numeral 10) as a matrix, rubber B (reference numeral 20) as a domain, and polypropylene (reference numeral 30). The rubber A10 and the rubber B20 form a sea-island structure (that is, the rubber A and the rubber B are incompatible), and the polypropylene 30 is added to the rubber A10 and the rubber B20 by adding a small amount of the polypropylene 30 thereto. The rubber composition 100 forms a continuous phase (network) 30 of polypropylene 30 in the rubber composition 100. The continuous phase 30 can form a substantially continuous continuous phase. The inventors of the present application infer that the continuous phase 30 of the polypropylene 30 hardens the rubber composition 100 in an appropriate range, and as a result, the rigidity (shear elastic modulus, horizontal rigidity) is improved. Such a continuous phase of polypropylene also applies to the crosslinked rubber composition of the present invention, the highly attenuated laminate of the present invention, and the pneumatic tire of the present invention. In addition, the said mechanism is a presumption of this inventor to the last, and it is in the scope of the present invention even if the mechanism is other than the above.

  Applications of the rubber composition of the present invention include, for example, a rubber composition for a high damping laminate, a rubber composition for a pneumatic tire, a damping industrial belt, and the like.

The crosslinked rubber composition of the present invention will be described below.
The crosslinked rubber composition of the present invention is a crosslinked rubber composition containing a crosslinked rubber obtained by crosslinking the rubber composition of the present invention. The crosslinked rubber composition of the present invention can contain polypropylene in addition to the crosslinked rubber.

The crosslinked rubber composition of the present invention is not particularly limited as long as it uses the rubber composition of the present invention as a raw material. Examples of the vulcanization conditions include the same as described above.
In the crosslinked rubber composition of the present invention, the contained polypropylene is contained in the crosslinked rubber (especially rubber A and rubber B are incompatible with each other) from the viewpoint that both the damping property and the improvement in grip performance and rigidity can be achieved. Forming a continuous phase (network) is a preferred embodiment.

The rubber composition of the present invention or the crosslinked rubber composition of the present invention can achieve both improvement in damping property or grip performance and rigidity. Therefore, according to the rubber composition of the present invention or the crosslinked rubber composition of the present invention. For example, it is possible to reduce the size of the high attenuation laminate required to obtain the same characteristics (for example, attenuation).
Applications of the crosslinked rubber composition of the present invention include, for example, a rubber composition for a high damping laminate, a rubber composition for a pneumatic tire, a damping industrial belt, and the like.

The highly attenuated laminate of the present invention will be described below.
The high damping laminate of the present invention is obtained by alternately laminating the rubber composition of the present invention (the rubber composition for a high damping laminate of the present invention) or the crosslinked rubber composition of the present invention and a hard plate. It is a laminate.
The highly attenuated laminate of the present invention (hereinafter sometimes referred to as “the laminate of the present invention”) is formed by alternately laminating the above-described rubber composition of the present invention or the crosslinked rubber composition of the present invention and a hard plate. It is a high-damping laminate obtained by the above, and is a structure used for bridge support and building base isolation.

  In FIG. 1, the cross-sectional schematic of the high attenuation | damping laminated body showing an example of the embodiment of the laminated body of this invention is shown. In FIG. 1, the code | symbol 1 represents a high attenuation | damping laminated body (seismic isolation laminated body), the code | symbol 2 represents a hard board, and the code | symbol 3 represents the rubber composition (rubber composition for high attenuation | damping laminated bodies) of this invention.

As shown in FIG. 1 as an example, the high attenuation laminate 1 of the present invention includes a rubber composition (rubber composition for a high attenuation laminate) 3 of the present invention and a hard plate 2 (for example, a general structural steel plate, Cold rolled steel sheets and the like) are alternately laminated.
The high attenuation laminate 1 may be configured by providing an adhesive layer between the rubber composition (rubber composition for a high attenuation laminate) 3 of the present invention and the hard plate 2. You may comprise by vulcanizing directly, without providing.

In FIG. 1, the high attenuation laminate 1 of the present invention shows a state in which the rubber composition (rubber composition for a high attenuation laminate) 3 of the present invention and hard plates 2 are alternately laminated. However, the rubber composition (rubber composition for high attenuation laminate) 3 may have a structure in which two or more layers are laminated.
FIG. 1 shows an example of a total of 13 layers including 6 layers for the rubber composition (rubber composition for high attenuation laminate) 3 of the present invention and 7 layers for the hard plate 2. The number of laminations of the rubber composition (rubber composition for high attenuation laminate) 3 of the present invention and the hard plate 2 of the damping laminate 1 is not limited to this, depending on the application used, required characteristics, etc. Can be set arbitrarily.
Further, the size and overall thickness of the high attenuation structure 1 of the present invention, the layer thickness of the rubber composition (rubber composition for high attenuation laminate) 3 of the present invention, the thickness of the hard plate, etc. It can be arbitrarily set according to the intended use, required characteristics, and the like.

  In order to produce the laminate of the present invention, the rubber composition of the present invention (rubber composition for highly attenuated laminate) is molded into a sheet and then vulcanized to obtain a sheet-like rubber composition. A layer containing an adhesive may be provided and alternately laminated with a hard plate, or an unvulcanized rubber composition of the present invention (a rubber composition for a high attenuation laminate) is formed into a sheet shape in advance, After alternately laminating with the hard plate, heating and vulcanization and adhesion may be performed simultaneously.

Since the laminated body of the present invention uses the above-described rubber composition of the present invention, it has an effect of high damping and excellent rigidity.
Specifically, the equivalent damping constant (Heq), which is an index of damping performance measured by a lap shear shear test described later, is 0.21 or more, and the stiffness (Geq) measured similarly is 0.78 to 0.96. Can be.

The equivalent damping constant (Heq) and stiffness (Geq) are measured by a lap shear shear test.
FIG. 2 is a schematic side view of a sample for a lap shear type shear test. In FIG. 2, the code | symbol 4 represents the sample for a lap shear type shear test, the code | symbol 5 represents the rolled unvulcanized rubber composition, and the code | symbol 6 represents a steel plate.
The unvulcanized rubber composition 5 is an unvulcanized rubber composition of the rubber composition of the present invention that has been rolled to a size of 25 mm wide × 25 mm long × 5 mm thick. The steel plate 6 is a steel plate (width 25 mm × length 100 mm × thickness 20 mm) having a surface sandblasted and coated with a metal adhesive.
The sample 4 for lap shear type shear test is obtained by placing (stacking) the unvulcanized rubber composition 5 and the steel plate 6 as shown in FIG. 2 and then press vulcanizing at 130 ° C. for 120 minutes.

The lap shear shear test is performed under the following conditions using a vibrator (manufactured by Saginomiya), an input signal oscillator, and an output signal processor.
Using the lap shear type shear test sample prepared as described above, each time when a 175% strain was applied 10 times at a deformation frequency of 0.5 Hz by a biaxial shear tester at a measurement temperature of 23 ° C. Obtain the average shear characteristic value.
Specifically, the equivalent damping constant (Heq) and stiffness (Geq) are calculated according to the following equations (1) and (2) using Xmax and Qmax indicated by the hysteresis curve obtained in the lap shear type shear test. . FIG. 3 shows an example of a hysteresis curve obtained by a lap shear type shear test.

In equation (1), ΔW is the area of the hysteresis loop (the shaded area in FIG. 3).
In the formula (2), Keq is represented by the following formula (3), H represents the total thickness of the rubber layer laminated in the high attenuation laminate, and A is the cross-sectional area of the rubber layer.

Since the high damping laminate of the present invention is formed by using the rubber composition of the present invention (rubber composition for a high damping laminate) or the crosslinked rubber composition of the present invention, both the damping property and the rigidity are improved. Therefore, according to the high attenuation laminate of the present invention, the size of the high attenuation laminate required to obtain the same characteristic (eg, attenuation) can be reduced.
The use, application conditions, and the like of the high attenuation laminate are not particularly limited as long as the high attenuation laminate is used as a vibration energy absorber. Among these, since it has the above-described excellent characteristics, it is preferably used as a vibration energy absorption device for buildings. For example, various vibration energy absorption devices for vibration isolation, vibration isolation, vibration isolation, etc. Is suitably used for, for example, support of road bridges, basic isolation of bridges and buildings, seismic isolation of detached houses, metal bearings, and replacement of bearings.

The pneumatic tire of the present invention will be described below.
The pneumatic tire of the present invention is a pneumatic tire formed using the rubber composition of the present invention.
If the rubber composition used when forming the pneumatic tire of this invention is a rubber composition of this invention, it will not restrict | limit in particular. By forming the pneumatic tire of the present invention using the rubber composition of the present invention, both the grip performance and the rigidity can be improved. For example, a tread part, a side part, and a belt part of a pneumatic tire can be formed using the rubber composition of the present invention.
The pneumatic tire of the present invention is not particularly limited except that the rubber composition of the present invention is used for a pneumatic tire, and can be produced, for example, according to a conventionally known method. Moreover, as gas with which a tire is filled, inert gas, such as nitrogen, argon, helium other than the air which adjusted normal or oxygen partial pressure, can be used.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely according to an Example, this invention is not limited to the following Example.

<Manufacture of rubber composition (for high damping laminate)>
Each compound was blended so as to have the composition shown in Table 1 below (unit: parts by mass), kneaded for 5 minutes with a B-type Banbury mixer, and an unvulcanized rubber composition (rubber composition for high attenuation laminate) ) Was manufactured.

<Manufacture of highly attenuated laminate and crosslinked rubber composition>
The unvulcanized rubber composition obtained as described above was rolled into a size of 25 mm width × 25 mm length × 5 mm thickness.
An unvulcanized rubber composition after rolling (5 in FIG. 2) and a steel plate (25 mm wide × 100 mm long × 20 mm thick, 6 in FIG. 2) coated with a metal adhesive by sandblasting the surface. After placing (lamination) as shown in the side view of the lap shear type shear test sample 4 in FIG. 2, a high-attenuation laminate (crosslinked rubber composition) was produced by press vulcanization at 130 ° C. for 120 minutes. The obtained high attenuation laminate was used as a sample for a lap shear type shear test.

<Lap shear test>
The lap shear type shear test sample obtained as described above was subjected to a lap shear shear test using a vibrator (manufactured by Saginamiya), an input signal oscillator, and an output signal processor. The number of lap shear type shear test samples used in each example was ten.
Specifically, the shear characteristics of each time when 175% strain was applied 10 times at a deformation frequency of 0.5 Hz by a biaxial shear tester and a measurement temperature of 23 ° C. with respect to the lap shear type shear test sample. The average of the values was obtained.
Using Xmax and Qmax indicated by the hysteresis curve obtained by this lap shear shear test, average shear characteristic values (Heq, Geq) were determined according to the above formulas (1) and (2). The results are shown in Table 1 as damping constants and horizontal stiffness constants. The results of the damping constant and the horizontal stiffness constant are indicated by an index with Comparative Example 1 as a reference (100).

<Elongation at cutting, rigidity>
In accordance with JIS K6251: 2004, the rubber composition of the present invention after vulcanization was cut into 2 mm-thick dumbbell-shaped test pieces (dumbbell strip No. 3 shape), and the elongation at break [%] at 23 ° C. was measured. The results are shown in Table 1.

  In Comparative Example 1, the value of the horizontal stiffness constant [rigidity (Geq)] was 0.75, and the value of the damping constant [equivalent damping constant (Heq)] was 0.18.

The details of each component shown in Table 1 are as follows.
・ Rubber A1: Natural rubber, TSR20, manufactured by SIAM INDO RUBBER ・ Rubber B1: Vinyl-cisbutadiene rubber, UBEPOL-VCR412, Ube Industries, Ltd. ・ Rubber B2: Styrene-butadiene copolymer, Nipol 1502, manufactured by Nippon Zeon Carbon black 1: Diamond black I, manufactured by Mitsubishi Chemical Co., Ltd. Silanol group-containing inorganic filler 1: Silica, nip seal VN3, manufactured by Tosoh Silica, BET specific surface area 215 m ² / g
Silanol group-containing inorganic filler 2: Clay, SUPREX PLAY, manufactured by Kentucky Tennessee Clay Company, Ltd. Inorganic filler not containing silanol group 1: Calcium carbonate Inorganic filler not containing silanol group 2: Magnesium carbonate Petroleum resin 1 : High Resin # 120S (softening point 120 ° C, manufactured by Toho Chemical Co., Ltd.)
-Metal compound 1: Zinc oxide, Zinc Hana No. 3, manufactured by Shodo Chemical Industry Co., Ltd.-Polylactic acid 1: LACEA H-440 (melting point: 155 ° C, number average molecular weight: 78000, weight average molecular weight: 150,000, manufactured by Mitsui Chemicals, Inc. )
Polylactic acid 2: NatureWorks 4060D (softening point 81 ° C., weight average molecular weight 180000, manufactured by NatureWorks)
Polypropylene 1: Propylene homopolymer, trade name E-333GV, manufactured by Prime Polymer Co., Ltd. Polypropylene 2: Propylene homopolymer, trade name E-2900H, manufactured by Prime Polymer Co., Ltd. Polyethylene 1: Low density polyethylene (Homo polymer), trade name YF30, manufactured by Nippon Polyethylene Co., Ltd. ・ Sulfur 1: powder sulfur, manufactured by Hosoi Chemical Co., Ltd. ・ Vulcanization accelerator 1: Noxeller CZ, manufactured by Ouchi Shinsei Chemical Co., Ltd.

As is clear from the results shown in Table 1 and attached FIG. 4 (FIG. 4 is a graph showing the relationship between damping property and rigidity obtained in the example of the present invention), in Comparative Example 1, The rubber compositions (Comparative Examples 2 and 3) in which a polylactic acid resin was added to the prepared rubber composition for highly attenuated laminates showed improved rigidity as compared with Comparative Example 1, but reduced rigidity. Although the comparative example 4 which does not contain a polypropylene and contains polyethylene instead also improved the damping property as compared with the comparative example 1, the rigidity was lowered, and it was impossible to achieve both the damping property and the improvement in rigidity.
When too much polypropylene is blended, the horizontal rigidity is increased, but the elongation at break of 550% or more required for the rubber composition for a high-damping laminate cannot be obtained, and it breaks before exhibiting high damping performance. Further, fatigue was easily caused during repeated deformation, and the durability was poor (Comparative Example 5).
In contrast, the rubber compositions (rubber compositions for highly attenuated laminates) produced in Examples 1 to 10 have higher damping properties than Comparative Example 1, and the rigidity is improved without decreasing the rigidity. I understood that.
As described above, the rubber composition of the present invention (the rubber composition for a high-damping laminate) has a high damping property, and accordingly the rigidity is improved without decreasing the stiffness. Can be improved at the same time. Moreover, the rubber composition for highly attenuated laminates of the present invention is excellent in damping property, rigidity and durability at low temperature (23 ° C.), and excellent in low temperature performance.

<Manufacture of rubber composition (for pneumatic tire)>
In accordance with the formulation shown in Table 2 below (units for use amount of each component are parts by mass), components other than sulfur and a vulcanization accelerator are kneaded with a base at a rubber discharge temperature of 150 ° C. using a 16 L Banbury mixer. A kneaded paste was obtained. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 5 minutes at 70 ° C. using an open roll to obtain an unvulcanized rubber composition.
<Manufacture of pneumatic tires>
The unvulcanized rubber composition obtained as described above was molded into a tread shape, and bonded together with other tire members, placed in a tire mold at 170 ° C., and press vulcanized for 15 minutes to produce a pneumatic tire. Obtained.

<Evaluation>
Using the rubber composition (for pneumatic tire) and pneumatic tire obtained as described above, hardness, 100% modulus, and grip properties were evaluated by the following methods. The results are shown in Table 2.
(hardness)
A test piece of a predetermined size is cut out from the tread rubber of the pneumatic tire manufactured as described above, and is measured at room temperature with a spring type A according to JIS K 6253 “Testing method for hardness of vulcanized rubber and thermoplastic rubber”. Hardness was measured. When the hardness is large, the rigidity tends to increase. In the present invention, the hardness is used as an index of the stiffness of the pneumatic tire.
(100% modulus)
In accordance with JIS K6251: 2004, a dumbbell-shaped test piece having a thickness of 2 mm is obtained from a vulcanized rubber obtained by press-vulcanizing the unvulcanized rubber composition obtained as described above for 45 minutes at 148 ° C. ( Dumbbell strip No. 3) was cut out, and 100% modulus (M ₁₀₀ ) [MPa] at 23 ° C. was measured using this. It was to evaluate the rigidity from M _100.
(Grip performance)
The braking torque of the pneumatic tire manufactured as described above was measured with a drum testing machine, and the result was expressed as an index value with the braking torque value of Comparative Example 6 corresponding to a conventional pneumatic tire as 100, and the grip Performance was evaluated. The greater this value, the better the braking / driving performance (grip performance).

Details of the components shown in Table 2 are as follows.
Rubber B3 (SBR): Styrene butadiene rubber (SBR), N9520 manufactured by Nippon Zeon Co., Ltd. (bonded styrene content: 35.0% by weight)
Carbon black 2: Dia Black SA manufactured by Mitsubishi Chemical Corporation (N ₂ SA: 137 m ² / g)
Silanol group-containing inorganic filler 3 (silica): Silica, Ultraseal VN3 (BET: 175 m ² / g) manufactured by Degussa
Silane coupling agent 1: bis- [3- (triethoxysilyl) -propyl] tetrasulfide, trade name: Si69, manufactured by DEGGASA ・ Aroma oil 1: Process X-140 manufactured by Japan Energy Co., Ltd.
・ Stearic acid: manufactured by Nippon Oil & Fats Co., Ltd. ・ Metal compound 2 (zinc flower): Zinc flower, manufactured by Mitsui Mining & Smelting Co., Ltd. ・ Wax: Ozoace 0355 manufactured by Nippon Seiwa Co., Ltd.
Anti-aging agent 1: Antigen 6c (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical Co., Ltd.
Sulfur 2: manufactured by Tsurumi Chemical Co., Ltd. In addition, rubber A1, polylactic acid 1, polypropylene 1, and vulcanization accelerator 1 in Table 2 are the same as those used in Table 1.

As is apparent from the results shown in Table 2, Comparative Examples 6 and 7 not containing polypropylene had 100% modulus, low hardness and poor rigidity, and low grip performance.
In contrast, Examples 11 and 12 had 100% modulus, high hardness and excellent rigidity, and were able to achieve both grip performance and rigidity.

The morphology of the rubber composition of the present invention will be described below with reference to the accompanying drawings.
FIG. 6 is a photograph of one example of the morphology of the rubber composition of the present invention observed with a scanning probe microscope (SMP).
The rubber composition sample (unvulcanized) used in FIG. 6 is composed of 61 parts by mass of rubber A1 (NR) shown in Table 1 and rubber shown in Table 1 as two or more types of crosslinkable rubber components. 36 parts by mass of B1 (BR) and polypropylene 1 (3 parts by mass) shown in Table 1 are contained.
Measurement with a scanning probe microscope was performed at 23 ° C. The obtained photograph is an enlarged cross section of the sample 3500 times. It is considered that the phase portion of the same color reflects the same hardness in the measurement result by the scanning probe microscope.
In FIG. 6, the rubber composition 60 has a soft phase 61 as a matrix, and has a hard phase 63 that is elongated in the matrix.
Since the hardest of the rubber component and polypropylene contained in the sample is polypropylene, the phase 63 that is elongated in the phase 61 is considered to be polypropylene.
Thus, the results of FIG. 6 are believed to suggest that polypropylene forms a continuous phase (network) of polypropylene in the rubber composition.
Moreover, although the polypropylene in the sample has only 3 parts by mass, the phase 63 in FIG. 6 occupies a relatively wide part and forms a substantially continuous continuous phase. This is believed to prove that polypropylene is unevenly distributed at the interface between incompatible rubber A and rubber B to form a continuous phase of polypropylene in the rubber composition, as shown in FIG. .

1 High attenuation laminate (Seismic isolation laminate)
2 Hard plate 3 Rubber composition of the present invention (rubber composition for highly attenuated laminate)
4 Sample for lap shear type shear test 5 Rolled unvulcanized rubber composition 6 Steel plate 10 Rubber A
20 Rubber B
30 Polypropylene (continuous phase)
60 Rubber composition 61, 63 Phase 100 Rubber composition of the present invention (crosslinked rubber composition) (rubber composition for highly attenuated laminate)

As is apparent from the results shown in Table 2, Comparative Examples 6 and 7 not containing polypropylene had 100% modulus, low hardness and poor rigidity, and low grip performance.
In contrast, Reference Examples 1 and 2 had 100% modulus, high hardness and excellent rigidity, and were able to achieve both grip performance and rigidity.

Claims (18)

  100 parts by mass of two or more kinds of crosslinkable rubber components, 10-100 parts by mass of an inorganic filler having a silanol group, 0.1-30 parts by mass of a polylactic acid resin, and 0.1-10 parts by mass of polypropylene, Containing a rubber composition.   The rubber composition according to claim 1, wherein the rubber component is a diene rubber.   The rubber composition according to claim 1, wherein the rubber component includes rubber A and rubber B, and the rubber A and the rubber B are incompatible.   The rubber component includes rubber A and rubber B, the rubber A is at least one selected from the group consisting of natural rubber and polyisoprene, and the rubber B is selected from the group consisting of polybutadiene and a butadiene copolymer. The rubber composition according to claim 1, which is at least one kind.   The rubber composition according to claim 3 or 4, wherein a mass ratio of the rubber A and the rubber B (rubber A / rubber B) is 90/10 to 10/90.   The rubber composition according to any one of claims 1 to 5, further comprising 5 to 50 parts by mass of a petroleum resin with respect to 100 parts by mass of the rubber component.   The rubber composition according to any one of claims 1 to 6, further comprising 5-55 parts by mass of an inorganic filler other than the inorganic filler having a silanol group with respect to 100 parts by mass of the rubber component.   The rubber composition according to claim 1, wherein the polylactic acid resin has a melting point of 180 ° C. or lower.   The rubber composition according to any one of claims 1 to 8, wherein the polylactic acid resin has a number average molecular weight of 1,000 to 200,000.   The mass ratio of the inorganic filler having a silanol group and the polylactic acid resin (inorganic filler having a silanol group / polylactic acid resin) is 1/1 to 10/1. A rubber composition according to any one of the above.   The rubber composition according to any one of claims 1 to 10, further comprising carbon black, wherein the amount of the carbon black is 10 to 90 parts by mass with respect to 100 parts by mass of the rubber component.   The rubber according to claim 1, further comprising a silane coupling agent, wherein the amount of the silane coupling agent is 1 to 10 parts by mass with respect to 100 parts by mass of the inorganic filler having the silanol group. Composition.   The rubber composition according to claim 3, wherein the polypropylene forms a continuous phase in the rubber component.   A crosslinked rubber composition containing a crosslinked rubber, which is obtained by crosslinking the rubber composition according to claim 1.   A rubber composition for a high damping laminate, wherein the rubber composition according to any one of claims 1 to 13 or the crosslinked rubber composition according to claim 14 is used for a high damping laminate.   A rubber composition for a pneumatic tire, wherein the rubber composition according to any one of claims 1 to 13 or the crosslinked rubber composition according to claim 14 is used for a pneumatic tire.   A high attenuation laminate obtained by alternately laminating the rubber composition for a high attenuation laminate according to claim 15 and a hard plate.   A pneumatic tire formed using the rubber composition for a pneumatic tire according to claim 16.