JP2836870B2 - Composition with excellent vibration damping properties - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a composition exhibiting excellent vibration damping performance over a wide temperature range and having excellent vibration damping properties.

[Conventional technology]

2. Description of the Related Art In recent years, with the development of transportation such as automobiles, noise and vibration resulting therefrom have become major social problems. In addition, high demands for low vibration and low noise have been demanded inside the automobile. In addition, office equipment such as copiers and printers have been widely used in ordinary households, and reduction of noise and vibration generated by these equipment has become an important issue. Furthermore, household appliances are becoming larger due to changes in lifestyles, and low vibration and low noise of appliances with vibration, such as refrigerators, washing machines, and vacuum cleaners, are also important in terms of quiet performance as a product. It is one.

Conventionally, various springs, vibration-proof rubbers, and the like have been used to reduce the vibration and noise, but cannot meet the various requirements described above. This method is to reduce the generation of vibration and noise by interrupting the transmission of vibration. In addition to this, a method called vibration suppression, which suppresses vibration itself, has become widespread.
This is a method of sticking or sandwiching various viscoelastic bodies to a vibrating object to suppress the occurrence of vibration. As a damping material used for this purpose, there is known a damping material containing polyisoprene containing 3,4 bonds and 1,2 bonds in a proportion of 60% or more (Japanese Patent Publication No. 55-5540). ). However, the temperature range in which such polyisoprene exhibits damping performance is relatively narrow, and there is a risk that the polyisoprene will hardly function if it is out of the temperature range set in advance to exhibit damping performance. May not show sufficient damping performance due to changes in

[Problems to be solved by the invention]

Thus, an object of the present invention is to newly provide a vibration damping material capable of exhibiting sufficient vibration damping performance in a wide temperature range.

[Means for solving the problem]

According to the present invention, the object is to provide a polymer of isoprene or a mixture of isoprene and butadiene having a 3,4 bond and 1,2 bond content of 40% or more and having a main dispersion peak of tan δ at 0 ° C. or more. (But not containing a polymer having a structure having three or more branches), or a composition containing a polymer in which at least a part of the carbon-carbon double bond in the chain is hydrogenated, and an isobutylene-based polymer It is solved by providing things.

The polymer of isoprene or a mixture of isoprene and butadiene used in the present invention or a polymer in which at least a part of the carbon-carbon double bond in the chain is hydrogenated is tan.
It shows excellent vibration damping properties near the peak temperature of the main dispersion of δ. Further, by combining the isobutylene-based polymer, the temperature range exhibiting the vibration damping property can be sufficiently widened, and the application range can be further widened.

 Hereinafter, the present invention will be described in more detail.

In the present invention, a polymer of isoprene or a mixture of isoprene and butadiene, or a polymer in which at least a part of the carbon-carbon double bond in the chain is hydrogenated has 40% or more of 3,4 bonds and It contains 1,2 bonds and has a main dispersion peak of tan δ at 0 ° C. or higher.

In the case where a mixture of isoprene and butadiene is used, if the ratio of butadiene in the mixture becomes too large, the temperature at which the vibration damping performance becomes lower than normal temperature is not practically preferable. In this case, if the proportion of isoprene is 40% or more, the vibration control performance is exhibited at 0 ° C. or more. When a mixture of isoprene and butadiene is used, the form of the polymer may be any of random, block, and tapered.

The polymer of the present invention comprising isoprene or a mixture of isoprene and butadiene has a 3,4 bond and 1,2 bond content of 40.
% Or more (may be 100%). 3,4
When the content of the bond and the 1,2 bond is less than 40%, sufficient vibration damping performance cannot be obtained in a normal use temperature range, which is not preferable.

Further, it is necessary that the peak temperature of the main dispersion of tan δ (loss tangent) obtained by measuring the viscoelasticity of the polymer is 0 ° C. or more. If there is only a peak at a temperature lower than 0 ° C., sufficient vibration damping performance cannot be obtained in a normal temperature range. When the content of 3,4 bonds and 1,2 bonds of the isoprene polymer is 100%, the peak temperature of the main dispersion of tan δ is about 60%.
° C, the possible upper limit is about 60 ° C.

The polymer comprising isoprene or a mixture of isoprene and butadiene may be one in which at least a part of the carbon-carbon double bond in the polymer is hydrogenated.
The hydrogenation rate is determined according to the required levels of heat resistance and weather resistance. When high durability is required, the hydrogenation rate is preferably set to 50 mol% or more.

The number average molecular weight of the polymer comprising isoprene or a mixture of isoprene and butadiene is preferably in the range of 30,000 to 100,000, and more preferably in the range of 80,000 to 800,000.

The polymer comprising isoprene or a mixture of isoprene and butadiene can be obtained by a known anionic polymerization method. For example, using an alkyl lithium compound as an initiator,
A method of polymerizing isoprene or a mixture of isoprene and butadiene can be exemplified. Here, as an example of the alkyl lithium compound, the number of carbon atoms of the alkyl residue is 1 to 10
Of these, methyl lithium, ethyl lithium, pentyl lithium and butyl lithium are particularly preferred. Further, for example, a dilithium compound such as naphthalenedilithium and dilithiohexylbenzene can be used. The amount of the initiator used is determined by the desired molecular weight, but is generally used in the range of 0.01 to 0.2 parts by weight based on 100 parts by weight of the total monomers used in the polymerization.

To make the microstructure of isoprene or a polymer composed of a mixture of isoprene and butadiene contain 40% or more of 3,4 bonds and 1,2 bonds and to have a main dispersion peak of tan δ at 0 ° C or more. Uses a Lewis base as a cocatalyst in the polymerization of isoprene or a mixture of isoprene and butadiene. Examples of Lewis bases include ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran; glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; triethylamine; N, N, N ', N'-tetramethylethylenediamine (TMEDA); Examples include amine compounds such as methylmorpholine. The amount of the Lewis base to be used is generally in the range of 0.1 to 1000 moles per mole of the initiator lithium.

In the polymerization, a solvent is preferably used for easy control. As the solvent, an organic solvent inert to the polymerization catalyst is used. Particularly, aliphatic, alicyclic and aromatic hydrocarbons having 6 to 12 carbon atoms are preferably used. Examples include hexane, heptanecyclohexane, methylcyclohexane, benzene and the like.

The polymerization is carried out in any of the polymerization methods at a temperature in the range of 0 to 80 ° C. for 0.5 to 50 hours.

When the polymer is hydrogenated, a known method is used, but a method of reacting molecular hydrogen with a known hydrogenation catalyst in a state of being dissolved in a solvent inert to the hydrogenation reaction or the hydrogenation catalyst. Is preferably used. The catalyst used is a heterogeneous catalyst such as Raney nickel, or a metal such as Pt, Pd, Ru, Rh, Ni supported on a simple substance such as carbon, alumina, or diatomaceous earth, or a transition metal and an alkyl aluminum compound. , A Ziegler-based catalyst or the like comprising a combination of an alkyllithium compound and the like. The reaction is
Hydrogen pressure is normal pressure to 200 kg / cm ² , reaction temperature is normal temperature to 2
The reaction is performed at 50 ° C. for a reaction time in the range of 0.1 to 100 hours.

The polymer after the reaction is obtained by coagulating the reaction solution with methanol or the like and then heating or drying under reduced pressure, or by pouring the reaction solution into boiling water and removing the solvent by azeotropic distillation, followed by heating or drying under reduced pressure. .

The isobutylene polymer which is another important component in the present invention will be described. Examples of the isobutylene-based polymer used here include a homopolymer of isobutylene, a copolymer of isobutylene and n-butene, and a copolymer of isobutylene and a conjugated diene. In the case of a copolymer, the proportion of other monomers is preferably about 20 mol% or less. The molecular weight of the isobutylene-based polymer is not particularly limited, but is in the range of 200 to 10000000.

The mixing ratio of the polymer and the isobutylene-based polymer is not particularly limited. However, in consideration of the actually used temperature and vibration damping performance, the weight ratio is within the range of the former / the latter 95/5 to 30/70. Preferably, there is.

Since the composition of the present invention contains an isobutylene-based polymer, when a polymer of isoprene or a mixture of isoprene and butadiene is used alone, vibration damping properties are obtained even in a low-temperature region where vibration damping performance is not exhibited. Show.

In many cases, the composition of the present invention needs to be crosslinked with a crosslinking agent in practical use. As the cross-linking agent used for cross-linking, those used in a usual rubber industry are used, but sulfur, peroxide and the like are preferable.

The composition according to the present invention is used by blending various compounding agents as necessary. Examples include rosin, terpenes,
Examples include tackifying resins such as petroleum resins, plasticizers such as DOP, DOA and process oil, reinforcing agents such as carbon black, silica, calcium carbonate, and mica, fillers, and coloring agents. Of these, mica is particularly preferably used because it improves vibration damping performance. The amount of these ingredients used is 10 to 300 parts by weight for the tackifier resin, 2 for the reinforcing agent and 2 for the filler.
It is preferably used in an amount of 0 to 250 parts by weight and mica in an amount of 20 parts by weight or more.

In some cases, other polymers may be blended and used without impairing the gist of the present invention. In this case, natural rubber, isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), styrene-ethylenebutylene-styrene block copolymer, styrene-ethylenepropylene-styrene block copolymer, Styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer and the like are preferably used. The blending ratio of these polymers is preferably used at 30% by weight or less.

The composition of the present invention is a polymer of isoprene or a mixture of isoprene and butadiene, and an isobutylene-based polymer,
If necessary, the composition can be mixed with another compounding agent using an open roll, a Banbury, a kneader, or the like. Further, if necessary, it is used after being molded and cross-linked by extrusion, pressing or the like.

The composition of the present invention is used as it is as a molded product, or in the form of being attached to or sandwiched on a metal or plastic plate.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples.

In addition, each measured value in an Example was calculated | required by the following method.

 The number average molecular weight was determined by GPC.

The microstructure was measured by NMR spectrum, δ 4.8 ppm, δ
5.8 ppm peak corresponding to 3,4 and 1,2 bonds and δ 5.
From the ratio of peaks corresponding to 1,4 bonds of 3 ppm, 3,4 bonds and 1,1 bonds
The content of two bonds was calculated.

The hydrogenation rate was calculated from the ratio of the iodine values of the block copolymer before and after the hydrogenation reaction.

The peak temperature of tan δ was determined by measuring a viscoelastic spectrum with Leo Vibron (manufactured by Orientec).

The loss coefficient (η), which indicates the damping performance, is determined by a resonance method in which a sample, in which a damping composition is adhered to a 1-mm-thick steel sheet, is vibrated by a vibrator and the degree of resonance of the sample is measured. Was. The measurement frequency was 500 Hz and the measurement temperature was 40, 20, 0.
It was used as an index of the range of the temperature range showing the vibration damping performance at ℃.

Example 1, Comparative Example 1 600 ml of hexane as a solvent, 0.2 ml of n-BuLi as a polymerization catalyst, and 0.2 ml of TMEDA as a vinylating agent were added to a pressure-resistant reactor dried and replaced with nitrogen, and the temperature was raised to 50 ° C. After that, 200 ml of isoprene monomer was added for polymerization. The polymer was recovered by treating the polymerization solution with methanol. The obtained polymer was dried under vacuum to obtain an isoprene polymer (I).

The number average molecular weight of the obtained isoprene polymer (I) is 18
The total amount of 0000, 3,4 bonds and 1,2 bonds was 78.5%.

The obtained isoprene polymer (I) and a copolymer of isobutene and 1-butene (isobutene / 1-butene = about 85/15 (wt / wt), molecular weight as various isobutylene-based polymers)
Table 1 shows 1450; polybutene HV-300, manufactured by Nippon Petrochemical), polyisobutylene (molecular weight: 35,000, Vistanex LM; manufactured by Nippon Butyl), and butyl rubber (isoprene content: 1.6 mol%, molecular weight: about 350,000, manufactured by Policer). A vibration damping composition was prepared by blending according to the indicated formulation, and the loss coefficient was measured. As shown in Table 1, only the isoprene polymer (I) shows high damping performance at 40 ° C, but has a small loss coefficient at 20 ° C and 0 ° C, and the damping performance is insufficient. It is shown that. On the other hand, it can be seen that the composition of the present invention has a sufficiently high loss coefficient at any temperature and has vibration damping performance in a wide temperature range.

Example 2 Polymerization was carried out in the same manner as in Example 1 except that the amounts of the isoprene monomer and n-BuLi were changed, followed by hydrogenation using Pd-C as a catalyst to obtain an isoprene polymer (II). The number average molecular weight of the isoprene polymer (II) is 17300
The total amount of 0, 3, 4 bonds and 1, 2 bonds is 73.4%, and the hydrogenation rate is 78.
2%. The peak temperature of tan δ was 36.8 ° C.

The isoprene polymer (II) and polyisobutylene (Vistanex LM) were blended according to the formulation shown in Table 2 to prepare a damping composition, and the loss factor was measured. As can be seen from the results shown in Table 2, the composition of the present invention exhibits vibration damping performance in a wide temperature range.

[Effects of the Invention] The present invention provides a damping material exhibiting sufficient damping performance in a wide temperature range.

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Claims (1)

(57) [Claims] 1. A polymer of isoprene or a mixture of isoprene and butadiene having a content of 3,4 bonds and 1,2 bonds of 40% or more, and having a main dispersion peak of tan δ at 0 ° C. or higher (3 A polymer having at least a portion of a carbon-carbon double bond in the chain thereof, and an isobutylene-based polymer.