JP7380012B2 - rubber composition - Google Patents

Description

The present invention relates to a new rubber composition containing butyl rubber in combination with at least a specific aliphatic monomer polymeric resin and an aromatic monomer polymeric resin, and in particular, it relates to a rubber composition containing a combination of at least a specific aliphatic monomer polymeric resin and an aromatic monomer polymeric resin. The present invention relates to a novel rubber composition that can exhibit excellent vibration damping performance in the field, and a vibration damping material made from the same.

2. Description of the Related Art Vibration damping rubber has conventionally been used in the fields of automobiles, railway vehicles, housing equipment, etc. to prevent unnecessary vibrations.

In the automobile field, it is used as a mount material to suppress vibrations from the engine.In recent years, engines and exhaust pipes generate higher heat due to the trend toward higher efficiency, and these also need to be controlled at high temperatures. Vibration performance is required.

As a composition that satisfies such requirements, for example, a composition in which a hydrogenated terpene phenol resin is blended with a rubber component consisting of an isobutylene-isoprene copolymer and a thermoplastic elastomer (see, for example, Patent Document 1), and A thermoplastic elastomer consisting of an isobutylene-isoprene copolymer and a polystyrene-vinyl polyisoprene block copolymer is blended with at least one selected from terpene resin, C5 petroleum resin, or fully hydrogenated petroleum resin. , a vibration damping rubber that can be used in a wide temperature range (for example, see Patent Document 2), and furthermore, a material oil with an indene content of 60 to 90% is free-formed in the presence of a phenol compound for an ethylene copolymer. A vibration damping material containing an aromatic petroleum resin polymerized using a Dell-Crafts catalyst and having a softening point of 80 to 115°C and exhibiting excellent damping performance at 25 to 40°C (for example, see Patent Document 3). ), etc. have been proposed.

Japanese Patent Application Publication No. 2018-203894 JP2010-254923A JP-A-6-9853

However, none of the compositions proposed in Patent Documents 1 to 3 have been able to exhibit stable vibration damping performance over a wide temperature range under the usage environment that has become more demanding in recent years, especially in high temperature ranges. The emergence of materials that exhibit better vibration damping performance is expected.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a novel rubber composition that solves the above problems and has excellent vibration damping performance in a high temperature region, particularly in a high temperature region of 50° C. or higher.

As a result of intensive research in order to solve the above problems, the present inventors have discovered that high temperature The present inventors have discovered that a new rubber composition exhibits excellent vibration damping performance in the high temperature range, particularly in the high temperature range of 50° C. or higher, and have completed the present invention.

That is, the present invention provides at least 5 to 100 parts by weight of an aliphatic monomer polymeric resin (B) having an aromatic monomer residue component of less than 30 wt%, based on 100 parts by weight of butyl rubber (A), The present invention relates to a rubber composition characterized in that it contains 5 to 100 parts by weight of an aromatic monomer polymeric resin (C) in which the group monomer residue component is 70 wt% or more.

The present invention will be explained in detail below.

In the rubber composition of the present invention, at least 5 to 100 parts by weight of an aliphatic monomer polymeric resin (B) containing less than 30 wt% of an aromatic monomer residue component per 100 parts by weight of butyl rubber (A). , a novel rubber composition containing 5 to 100 parts by weight of an aromatic monomer polymerized resin (C) having an aromatic monomer residue component of 70 wt% or more, and further containing an inorganic filler (D), etc. It may include.

The rubber composition of the present invention uses butyl rubber, and by using butyl rubber, it becomes possible to easily provide a novel rubber composition that has excellent vibration damping performance in a high temperature range. The butyl rubber in this case may be any one that belongs to the category called butyl rubber, such as polyisobutylene rubber, isobutylene-isoprene rubber, chlorinated butyl rubber with halogen introduced, brominated butyl rubber, used butyl tube, etc. Examples include butyl recycled rubber manufactured using rubber as a raw material. These may be used alone or in combination. In particular, isobutylene-isoprene rubber is preferred because it provides a rubber composition with excellent vibration damping properties.

The aliphatic monomer polymerized resin (B) constituting the rubber composition of the present invention is an aliphatic monomer polymerized resin containing less than 30 wt% of aromatic monomer residue components, and has an aromatic monomer residue component of less than 30 wt%. It may be a homopolymer resin of monomer or an aliphatic monomer-aromatic monomer copolymer resin. Note that the aliphatic monomer polymerized resin may be in the category commercially referred to as (aliphatic) petroleum resin. Here, when the aromatic monomer residue component is 30 wt% or more, the compatibility with the rubber component is poor, it is difficult to impart vibration damping properties in a low temperature range, and the rubber composition has a wide temperature range. It becomes difficult to make it into an object.

The aliphatic monomer constituting the aliphatic monomer polymerized resin (B) may be any one that belongs to the category called aliphatic monomers, such as chain-like monomers such as isoprene and piperylene. Aliphatic: Cyclic aliphatic such as cyclopentadiene, methylcyclopentadiene, dicyclopentadiene, methyldicyclopentadiene, and dimethyldicyclopentadiene. Further, these may be used alone or in combination. Furthermore, there may be mentioned a fraction with a boiling point range of 20 to 110° C. (sometimes referred to as a C5 fraction) obtained by thermal decomposition of petroleum.

In addition, when the aliphatic monomer polymerized resin (B) is an aliphatic monomer-aromatic monomer copolymer resin, the aromatic monomer is referred to as an aromatic monomer. Examples thereof include styrenes such as styrene, vinyltoluene, α-methylstyrene and β-methylstyrene; indenes such as indene and methylindene. Further, these may be used alone or in combination. Furthermore, there may be mentioned a fraction (sometimes referred to as a C9 fraction) having a boiling point range of 140 to 280° C. obtained by thermal decomposition of petroleum.

The amount of the aliphatic monomer polymerized resin (B) is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, based on 100 parts by weight of the butyl rubber (A). Here, if the amount is less than 5 parts by weight, the resulting composition will be poor in improving damping properties. On the other hand, if it exceeds 100 parts by weight, the resulting composition will have poor processability.

The aliphatic monomer polymerized resin (B) has a softening point of 90 to 120°C, particularly 90 to 110°C, because it has an excellent effect of improving damping properties in a particularly wide temperature range. Preferably, it is an aliphatic monomer polymeric resin. In addition, those having a weight average molecular weight (sometimes referred to as Mw) of 500 to 6000, especially 600 to 4000, when measured as a standard polystyrene equivalent value using gel permeation chromatography (sometimes referred to as GPC). preferable.

The aromatic monomer polymerization resin (C) constituting the rubber composition of the present invention is an aromatic monomer polymerization resin in which the aromatic monomer residue component exceeds 70 wt%. It may be a homopolymer resin of monomer or an aliphatic monomer-aromatic monomer copolymer resin. Note that the aliphatic monomer-aromatic monomer copolymer resin may be in the category commercially referred to as (aromatic) petroleum resin. Here, if the aromatic monomer residue component is 70 wt% or less, it is difficult to impart vibration damping properties in a high temperature range, and it is difficult to provide a rubber composition with excellent vibration damping properties in a high temperature range. becomes.

As the aromatic monomer and aliphatic monomer constituting the aromatic monomer polymeric resin (C), the same ones as exemplified above for the aliphatic monomer polymeric resin (B) may be mentioned. I can do it.

The amount of the aromatic monomer polymerized resin (C) is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, based on 100 parts by weight of the butyl rubber (A). Here, if the amount is less than 5 parts by weight, the resulting composition will be poor in improving damping properties. On the other hand, if it exceeds 100 parts by weight, the resulting composition will have poor processability.

The aromatic monomer polymerized resin (C) is an aromatic monomer polymer having a softening point of 100 to 140°C, particularly 110 to 140°C, since it has an excellent effect of improving vibration damping properties at high temperatures. A monomer polymeric resin is preferred. Further, it is preferable that the Mw is 500 to 8,000, particularly 1,000 to 6,000 when measured as a standard polystyrene equivalent value using GPC.

The rubber composition of the present invention is obtained by blending the aliphatic monomer polymer resin (B) and the aromatic monomer polymer resin (C) into the butyl rubber (A). , it exhibits excellent vibration damping properties in a high temperature region, particularly in a high temperature region of 50° C. or higher.

Note that any method may be used for producing the aliphatic monomer polymerized resin (B) and the aromatic monomer polymerized resin (C), and the above-mentioned aliphatic monomers, aromatic Examples include a method in which a polymerization reaction is carried out using a polymerization catalyst using group monomers, mixtures thereof, and the like. The polymerization catalyst in this case is not particularly limited, and examples thereof include aluminum trichloride, aluminum tribromide, boron trifluoride, and complexes thereof.

The rubber composition of the present invention further contains an inorganic filler (D) in addition to an aliphatic monomer polymeric resin (B) and an aromatic monomer polymeric resin (C) to the butyl rubber (A). Can be blended.

The rubber composition of the present invention preferably contains an inorganic filler (D) because it has excellent strength, durability, and processability. Examples of the inorganic filler in this case include those commonly added to rubber, such as carbon black, silica, calcium carbonate, talc, clay, mica, alumina, aluminum hydroxide, etc. . Further, these inorganic fillers may be used alone or in combination of two or more. In this case, the amount of the inorganic filler (D) to be blended is preferably 5 to 300 parts by weight, particularly 10 to 200 parts by weight, based on the butyl rubber (A).

Furthermore, the rubber composition of the present invention may contain a crosslinking agent. The crosslinking agent in this case is not particularly limited, and examples thereof include sulfur, alkylphenol resins, quinoid crosslinking agents, thiuram crosslinking agents, and the like. Further, a crosslinking accelerator can be blended with the crosslinking agent, and the crosslinking accelerator is not particularly limited, and examples include thiazole type, thiuram type, thiourea type, sulfenamide type, dithiocarbamate type, and guanidine type. and crosslinking accelerators such as mixtures thereof.

The rubber composition of the present invention may further contain compounding agents commonly used in the rubber industry, such as softeners, anti-aging agents, zinc oxide, magnesium oxide, stearic acid, etc., in the usual amounts. It can be used within the range of

The rubber composition of the present invention comprises the above-mentioned butyl rubber (A), aliphatic monomer polymeric resin (B), aromatic monomer polymeric resin (C), and optionally an inorganic filler (D). If necessary, various compounding agents selected as appropriate may be blended and mixed using a mixing method such as a Banbury type mixer, a pressure kneader, or an open roll. Furthermore, the obtained unvulcanized compound can be manufactured into a vulcanized rubber composition by, for example, molding it into a sheet using a calendar, roll, extruder, etc., and then crosslinking it in a heat medium. I can do it.

According to the present invention, an aliphatic monomer polymeric resin containing less than 30 wt% of an aromatic monomer residue component and an aromatic monomer polymerization resin containing 70 wt% or more of an aromatic monomer residue component, based on butyl rubber. By blending specific amounts of each polymeric resin, it is possible to provide a rubber composition for vibration damping materials that exhibits excellent vibration damping performance in high temperature regions, particularly in high temperature regions of 50°C or higher. Become.

EXAMPLES The present invention will be explained in more detail below using Examples and Comparative Examples, but the present invention is not limited to these Examples. The raw materials, analysis, and test methods used in the Examples and Comparative Examples are as follows.

1. Raw materials 1) Resin raw material dicyclopentadiene: Fuji Film Wako Pure Chemical reagent.
Styrene: Fujifilm Wako Pure Chemical reagent.
Indene: Fuji Film Wako Pure Chemical reagent.
Toluene: Fujifilm Wako Pure Chemical reagent, super dehydration grade.
Pentane: Fuji Film Wako Pure Chemical reagent.
Isoprene: Fujifilm Wako Pure Chemical reagent.
Piperylene: Reagent manufactured by Fuji Film Wako Pure Chemical Industries.
Dicyclopentadiene: Reagent manufactured by Fuji Film Wako Pure Chemical Industries.
Raw materials used for polymerization were prepared to have a predetermined composition. The composition of the raw materials is shown in Tables 1 and 2. Note that DCPD in Table 2 is an abbreviation for dicyclopentadiene.
Cyclopentadiene was used by thermally decomposing dicyclopentadiene at 200°C.
Polymerization catalyst: boron trifluoride butanol (manufactured by Stella Chemifa).
Polymerization catalyst: boron trifluoride phenol (manufactured by Stella Chemifa).

2) Rubber composition raw material butyl rubber: manufactured by JSR (trade name) BUTYL268.
Carbon black: Manufactured by Asahi Carbon Co., Ltd. (Product name) Asahi #70.
Calcium carbonate: Made by Maruo Calcium Co., Ltd., heavy calcium carbonate.
Process oil: Manufactured by Idemitsu Kosan Co., Ltd. (trade name) Diana Process Oil AH-16.
Zinc oxide: Manufactured by Sakai Chemical Industry.
Stearic acid: Manufactured by Kishida Chemical Co., Ltd.
Sulfur: Manufactured by Tsurumi Chemical Industry Co., Ltd. (Product name) Sulfax 5.
Vulcanization accelerator (MBTS): Manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. (Product name) Noxela DM-P.
Vulcanization accelerator (TMTD): Manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. (Product name) Noxeler TT-P.

2. Analysis method <Aromatic monomer residue component content in aliphatic monomer-aromatic monomer copolymer resin>
The amount of monomer in the oil before and after polymerization was measured using gas chromatography in accordance with JIS K-0114 (2000), the copolymer composition was calculated from the monomer conversion rate, and the aromatic monomer residue component was calculated. I did it.

<Softening point>
Measured according to JIS K-2207.

<Average molecular weight>
The number average molecular weight (Mn) and weight average molecular weight (Mw) were measured by gel permeation chromatography using standard polystyrene as a standard substance.

<Vibration damping>
Tan δ was measured at a frequency of 10 Hz using a viscoelasticity measuring device (manufactured by UBM, (trade name) Rheogel E-4000), and the values at 50° C. and 75° C. were used as an index of damping performance. It was determined that the larger this value was, the better the damping properties were.

Production example 1 (preparation of raw material oil)
Aromatic oil A is prepared as a mixture of aromatic monomers (mixed oil), aromatic oil B is prepared as a mixture of aromatic monomers (mixed oil) using commercially available raw materials, and aliphatic oil is prepared as a mixture of aliphatic monomers (mixed oil). A, aliphatic oil B was prepared. The compositions of aromatic oils A and B are shown in Table 1. The compositions of aliphatic oils A and B are shown in Table 2.

Production Example 2 (Production of aliphatic monomer homopolymer resin, aromatic monomer homopolymer resin, aliphatic monomer-aromatic monomer copolymer resin)
By the method shown below, using aromatic oil A, aromatic oil B, aliphatic oil A, and aliphatic oil B, aliphatic monomer homopolymer resin A (hereinafter referred to as resin A), aliphatic monomer body-aromatic monomer copolymer resins B to D, F, G (hereinafter simply referred to as resins B to D, F, G), aromatic monomer homopolymer resin E (hereinafter referred to as resin E). ) were manufactured.

A glass autoclave with an internal volume of 2 liters was charged with 500 g of aliphatic oil A shown in Table 2. Next, after heating to 85° C. in a nitrogen atmosphere, 0.8 parts by weight of boron trifluoride butanol complex (manufactured by Stella Chemifa) as a Friedel-Crafts catalyst was added to 100 parts by weight of the raw oil to give 40 parts by weight. Polymerization was carried out at ℃ for 2 hours. After adding aqueous caustic soda solution, the aqueous phase was removed.

Then, 400 g of the obtained oil phase was added to a 0.5 liter separable flask equipped with a nitrogen introduction tube, a thermometer, and a degassing tube. Nitrogen was introduced from the nitrogen introduction tube at a flow rate of 7 ml/min, and the temperature was raised to 220° C. over 30 minutes, followed by further heating for 30 minutes to remove unreacted oil by distillation to obtain Resin A. Table 4 shows the physical properties of the resin A obtained.

Resins B to G were prepared in the same manner as Resin A, except that the blending ratios of aromatic oil A, aromatic oil B, aliphatic oil A, and aliphatic oil B and the polymerization conditions were as shown in Table 3. Got each. Table 4 shows the physical properties of each.

Example 1
To 100 parts by weight of butyl rubber, 50 parts by weight of resin A, 30 parts by weight of resin B, 40 parts by weight of carbon black, 10 parts by weight of calcium carbonate, 10 parts by weight of process oil, 3 parts by weight of zinc oxide, 1 part by weight of stearic acid, and a Banbury mixer. (Toyo Seiki (trade name) BR600) was used for kneading. Subsequently, 1.5 parts by weight of sulfur and 1 part by weight of a vulcanization accelerator (MBTS) were added, and after finishing kneading, sheeting was performed using an 8-inch roll to obtain an unvulcanized rubber composition.

Further, a vulcanized rubber composition was prepared by vulcanization using a steam heating press at a vulcanization temperature of 150° C. and a vulcanization time of 30 minutes, and a viscoelasticity test (vibration damping test) was conducted. The results are shown in Table 5.

Examples 2 to 5
An unvulcanized rubber composition and a vulcanized rubber composition were produced and evaluated in the same manner as in Example 1, except that the ingredients and amounts of the rubber composition were as shown in Table 5. Ta. The results are shown in Table 5.

Comparative examples 1 to 3
An unvulcanized rubber composition and a vulcanized rubber composition were produced and evaluated in the same manner as in Example 1, except that the ingredients and amounts of the rubber composition were as shown in Table 5. Ta. The results are shown in Table 5.

The obtained rubber composition had poor vibration damping properties in the high temperature range of 50°C to 75°C.

The novel rubber composition of the present invention has excellent vibration damping performance in a high temperature range of 50° C. or higher, and can be suitably used for products and members in fields where vibration damping performance is required.

Claims (6)

Based on 100 parts by weight of butyl rubber (A), at least 10 to 80 parts by weight of an aliphatic monomer polymeric resin (B) containing less than 30 wt% of aromatic monomer residues, aromatic monomer residues It is a rubber composition containing 10 to 80 parts by weight of an aromatic monomer polymeric resin (C) whose component is 70 wt% or more, and the butyl rubber (A) is an isobutylene-isoprene rubber, an aliphatic monomer polymeric resin ( B) is an aliphatic petroleum resin with a softening point of 90 to 120°C and a weight average molecular weight of 500 to 6,000, and aromatic monomer polymerized resin (C) is an aliphatic petroleum resin with a softening point of 100 to 140°C and a weight average molecular weight of 500 to 8,000. A rubber composition characterized in that it is an aromatic petroleum resin . The rubber composition according to claim 1, wherein the aliphatic monomer polymerized resin (B) is an aliphatic petroleum resin having a softening point of 90 to 110°C and a weight average molecular weight of 600 to 4,000 . The rubber composition according to claim 1 or 2, wherein the aromatic monomer polymerized resin (C) is an aromatic petroleum resin having a softening point of 110 to 140°C and a weight average molecular weight of 1000 to 6000. . The rubber composition according to any one of claims 1 to 3, further comprising 5 to 200 parts by weight of an inorganic filler (D) based on 100 parts by weight of the butyl rubber (A). 5. The method according to claim 4, wherein the inorganic filler (D) is at least one selected from the group consisting of carbon black, silica, calcium carbonate, talc, clay, mica, alumina, and aluminum hydroxide. Rubber composition. A damping material characterized by using the rubber composition according to any one of claims 1 to 5.