JPH03166247A - Vibration damping composition - Google Patents

Abstract

PURPOSE:To obtain a vibration damping composition, composed of a specific block copolymer and isobutylene-based polymer and capable of exhibiting excellent vibration damping performance within a wide temperature range. CONSTITUTION:A vibration damping composition obtained by blending (A) a block copolymer, containing (A1) blocks, having 2500-40000 number-average molecular weight, composed of a vinyl aromatic monomer (e.g. styrene) and linked to (A2) blocks composed of isoprene or an isoprene-butadiene mixture and having 10000-200000 number-average molecular weight and >=40wt.% content of 3,4 and 1,2-bonds and peaks of the main dispersion of tandelta at >=0 deg.C or partially hydrogenated blocks in the form of A1-(A2-A1)n or (A1-A2)n (n is >=1) and having 30000-300000 molecular weight with (B) an isobutylene-based polymer at (95/5)-(30/70) weight ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a thermoplastic damping composition that exhibits excellent damping performance over a wide temperature range.

[Conventional technology]

In recent years, with the development of transportation such as automobiles, noise and vibration caused by this have become a major social problem. Furthermore, high-level requirements such as low vibration and low noise are now required inside automobiles. Furthermore, office equipment such as copying machines and printers has come to be widely used in general households, and reducing the noise and vibration generated by these equipment has become an important issue.

Furthermore, due to changes in lifestyles, household electrical appliances are becoming larger, and quietness through low vibration and noise reduction of vibrating equipment such as refrigerators, washing machines, and vacuum cleaners is an important performance factor for products. It has become one. Conventionally, various springs, anti-vibration rubber, etc. have been used to reduce this vibration and noise, but these have become unable to meet the various demands described above. This method reduces the generation of vibrations and noise by blocking the transmission of vibrations, but a separate method called vibration damping, which suppresses vibration itself, has become widespread. This is a method of suppressing vibration by attaching or sandwiching these various viscoelastic materials to a vibrating object. Until now, the damping materials used for this purpose have been polyester-based (Japanese Patent Laid-Open No. 6
A large number of examples have been proposed, including polyamide systems (Japanese Patent Publication No. 56-159160), epoxy resin systems (Japanese Patent Publication No. 58-23426), etc. However, these methods require complicated operations during molding and construction, such as using an organic solvent solution, molding a fluid compound by casting, or gluing molded objects with adhesive. While this was necessary, there were also cases in which it became a health and safety issue. In addition, the obtained damping material has good adhesion to the target equipment when used, and exhibits sufficient elasticity to have sufficient shapeability when molded after lamination. There is also a need. Currently, there is no material that has sufficient vibration damping performance and satisfies all of the requirements, including workability during construction and formability after lamination. As a result of intensive studies on materials that meet the above-mentioned requirements, the present inventors found that a block copolymer consisting of a block consisting of a diene monomer having a certain ξ-chloro structure and a block consisting of an aromatic vinyl monomer, It has been found that this material has the above characteristics and is an excellent material for vibration damping materials (Japanese Patent Application No. 63-254657).

However, the temperature range in which such a block copolymer exhibits vibration damping performance is relatively narrow, and when it is actually used, it may not exhibit sufficient vibration damping performance due to changes in ambient temperature.

[Problem to be solved by the invention]

The present inventor has conducted further studies aimed at creating a vibration damping material that can exhibit sufficient vibration damping performance over a wide temperature range, and as a result has arrived at the present invention.

[Means to solve the problem]

According to the present invention, the above problem is solved when the number average molecular weight is 2500 to
A block of 40,000 vinyl aromatic monomers (
A) and isoprene or isoprene-butadiene mixtures with a number average molecular weight of 10,000 to 200,000.
and the content of 3.4 bonds and 1.2 bonds is 40% or more, and the block has a peak of janδΦ main dispersion above O'C, or at least a part of the carbon-carbon double bonds in the chain is It is composed of hydrogenated block (B), and the bonding form of the block is A-(B-A)n or (A
-B) Solved by a combination consisting of a block copolymer represented by n (n is an integer of 1 or more) and having a molecular weight of 30,000 to 300,000, and an isobutylene polymer. The block copolymer used in the present invention exhibits sufficient strength without undergoing a crosslinking reaction because the vinyl aromatic block (A) forms pseudo-crosslinking points, and the block copolymer consisting of isobrene or an isoprene-butadiene mixture ( Since B) has excellent elasticity, it has sufficient strength even when it is molded after being pasted together. In addition, this block copolymer has thermoplasticity and can be molded using photomelt, making molding extremely easy.

Furthermore, by combining isobutylene polymers, it becomes possible to sufficiently widen the temperature range in which vibration damping properties are exhibited, further widening the range of applications.

The present invention will be explained in more detail below. The first component of the block copolymer used in the present invention includes vinyl aromatic monomers such as styrene, α-methylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene,
Examples include -methylstyrene, 4-probylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-pendylstyrene, 4-(phenylbutyl)styrene, and the most preferred is styrene.

Further, as the second component of the block copolymer used in the present invention, it is suitable to use isoprene or a combination of isoprene and butadiene.

When other monomers are used, for example, butadiene alone, even if the 3,4 bond and 1,2 bond contents are increased, the temperature at which vibration damping performance is exhibited is below O''C, so it is not actually used. It cannot function at temperatures as high as
It can exhibit vibration damping performance in a practical temperature range up to around 100°C, and can be used in a wide range of applications, making it extremely meaningful from a practical standpoint. When using isoprene-butadiene together, if the proportion of isoprene is 40% or more, 0
Demonstrates vibration damping performance at temperatures above °C. The form of the block (B) when used together may be random, block, or tapered.

3 and 4 of the block portions of the block copolymer of the present invention, which are excluded from isoprene or a mixture of isoprene and butadiene.
The bond and 1,2 bond content is 40% or more (100%
%) is used.

If the content of 3,4 bonds and 1,2 bonds is less than 40%, sufficient vibration damping performance cannot be obtained in the normal operating temperature range, which is not preferable.

In addition, t obtained by measuring the viscoelasticity of the block copolymer
It is necessary that the temperature of the peak of the main dispersion of an δ (loss tangent) is 0°C or higher. If there is a peak only at a temperature lower than 0°C, sufficient damping performance cannot be obtained in a normal temperature range. In addition, 3 and 4 of the isoprene block
When the bond and 1,2 bond content is 100%, tan δ
Since the absorption temperature of is approximately 60°C, the possible upper limit is approximately 60°C. The molecular weight of block (B) consisting of isoprene or isoprene-butadiene is 10
A value in the range of 000 to 200,000 is used. If the molecular weight is smaller than the above range, the elastic properties will be impaired, which is not preferable. Moreover, if it is too large, the fluidity of the block polymer will deteriorate, which is not preferable.

The molecular weight of the vinyl aromatic block is 2500-40000
If the molecular weight is less than 2,500, the mechanical properties will deteriorate, and if it exceeds 40,000, the melt viscosity will become too high and thermoplasticity will be impaired, which is not preferable.

The block (B) consisting of isobrene or isobrene-butadiene may be one in which at least a portion of the carbon-carbon double bonds in the block are hydrogenated. The hydrogenation rate is determined depending on the required levels of heat resistance and weather resistance. If high durability is required, increase the hydrogenation rate to 5.
The content is preferably 0 mol% or more.

Further, the proportion of the block (A) consisting of vinyl aromatic group in the block copolymer is generally in the range of 5% by weight to 50% by weight. If the proportion of block (A) is less than 5% by weight, the mechanical properties of the block copolymer will be insufficient;
On the other hand, if it exceeds 50% by weight, the viscosity becomes extremely high, making processing difficult, and vibration damping performance also decreases.

The molecular weight of the block copolymer obtained is 30,000 to 30
Must be in the range 0000. Molecular weight is 30
If it is less than 000, the mechanical properties such as strength and elongation at break of the block copolymer itself will decrease. Also, 30,000
If it exceeds 0, workability will deteriorate. From this point of view, the molecular weight of the block copolymer is more preferably 80,000 to 2,500.
It is good that it is in the range of 00.

The block morphology of the block copolymer of the present invention is A(BA
)n, (AB)n are used. Here, n is an integer of 1 or more, and the upper limit thereof is not particularly limited, but is preferably a value of approximately 20 or less.

The block copolymer of the present invention can be obtained by the following various methods.

First, the block copolymer is polymerized by sequentially polymerizing a vinyl aromatic compound, isoprene, or isoprene-butadiene using an alkyllithium compound as an initiator, or by polymerizing a vinyl aromatic compound and then isoprene or an isoprene-butadiene mixture. Examples include a method of coupling with a coupling agent, or a method of sequentially polymerizing isoprene or an isoprene-butadiene mixture and then a vinyl aromatic compound using a diliutium compound as an initiator. Examples of alkyllithium compounds include alkyl compounds in which the alkyl residue has 1 to 10 carbon atoms, with methyllithium, ethyllithium, bentyllithium, and butyllithium being particularly preferred. As the coupling agent, dichloromethane, dibromomethane, dichloroethane, dibromoethane, dibromobenzene, etc. are used. Examples of dilithium compounds include naphthalene dilithium, dilithiohexylbenzene, and the like. The amount to be used is determined by the desired molecular weight, but approximately 0.01 to 0.00 parts by weight of each initiator per 100 parts by weight of all monomers used for polymerization. 2 parts by weight,
The coupling agent is used in an amount of about 0.04 to 0.8 parts by weight.

In order to make the microstructure of the block (B) consisting of isoprene or isoprene-ptadiene mixture have 40% or more of 3.4 bonds and 1.2 bonds, and a main dispersion peak of tan δ above O'C. Lewis bases are used as cocatalysts in the polymerization of isobrene or isoprene-butadiene mixtures. 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”-tetramethylethylene diane (TH
EDA). Examples include amine compounds such as N-methylmorpholine. The amount of these Lewis bases used is approximately 0.0% based on the number of moles of lithium in the polymerization catalyst. It is used in a range of 1 to 1000 times.

It is preferable to use a solvent during polymerization to facilitate control. As the solvent, an organic solvent inert to the polymerization catalyst is used. In particular, aliphatic, alicyclic, and aromatic hydrocarbons having 6 to 12 carbon atoms are preferably used. Examples include hexane, heptane, cyclohexane, methylcyclohexane, benzene, and the like.

Regardless of the polymerization method, the polymerization is carried out at a temperature range of 0 to 80'C for a period of 0.5 to 50 hours.

When block (B) is hydrogenated, a known method is used. A method is preferably used in which molecular hydrogen is reacted with a known hydrogenation catalyst in a state where it is dissolved in a solvent inert to the hydrogenation reaction and the hydrogenation catalyst. The catalyst used is Raney nickel or PL+Pdr Ru,
Heterogeneous catalysts such as metals such as Rh and Ni supported on carbon, alumina, diatoms, etc., or
A Ziegler series catalyst or the like consisting of a combination of a transition metal, an alkyl algo compound, an alkyl lithium compound, etc. is used. The reaction is carried out at a hydrogen pressure of normal pressure to 200 k
g/cm'', the reaction temperature is room temperature to 250°C, and the reaction time is 0.1 to 100 hours.

The block copolymer after the reaction can be produced by coagulating the reaction solution with methanol or the like and then drying it by heating or under reduced pressure, or by pouring the reaction solution into boiling water to remove the solvent by azeotropic distillation, and then drying it by heating or under reduced pressure. can get.

Another important aspect of the present invention, the isoptylene polymer, will be explained. Examples of the polymer used here include a homopolymer of inbutylene, a copolymer of isobutylene and n-butene, and a copolymer of isobutylene and conjugated diene. In the case of a copolymer, the proportion of other monomers is preferably approximately 20 mol% or less. The molecular weight of the isobutylene polymer is not particularly limited, but one in the range of 200 to 1,000,000 is used.

There is no particular restriction on the mixing ratio of the block copolymer and isobutylene polymer, but it is more preferable to use a weight ratio in the range of 95/5 to 30/70 from the viewpoint of temperature and vibration damping performance. ．． By mixing this isobutylene polymer, it becomes possible to exhibit vibration damping properties even in a low temperature range other than the temperature range in which the block copolymer originally exhibits vibration damping properties.

The kumiaimono of the present invention has thermoplasticity, can be processed into a shape using hot melt, and has excellent workability. That is, methods such as melt-kneading under heating using a molder or the like, coating while melting, or molding using a press, etc., or molding using an extruder, etc. are employed. In any of these methods, reactions such as crosslinking are not required, and by cooling after molding, a molded product exhibiting sufficient strength can be obtained.

The composition according to the present invention may be used by adding various additives as necessary. Examples include tackifying resins such as rosin, tempel, and petroleum resins, plasticizers such as DOP, DOA, and process oils, reinforcing agents such as carbon black, silica, calcium carbonate, and mica, fillers, and colorants. It will be done. Among these, mica is particularly preferably used because it improves vibration damping performance. The amounts of these compounding agents used are preferably in the range of IO to 300 parts by weight for the tackifier resin, 20 to 250 parts by weight for the reinforcing agent and filler, and 20 parts by weight or more for the strength.

Further, depending on the case, it is also possible to blend and use other polymers to the extent that the spirit of the present invention is not impaired. In this case, styrene-ethylene butylene-styrene block copolymer, styrene-ethylene propylene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, ethylene-vinyl acetate copolymer Combination etc. are more preferably used. The blending ratio of these polymers is preferably 30% by weight or less. The assembled bottom product of the present invention can be used as it is as a pre-shaped product, or by being coated on or sandwiched between metal, plastic, or other plates.

The composite according to the present invention can be used not only as a base, but also by blending it with various plastics. Examples of particularly preferred plastics include polyolefins, polyamides, styrene plastics,
Examples include polyester, ABS plastic, and polycarbonate. It is preferable that the blend ratio of these plastics is 50% by weight or less.

Blending with these plastics is carried out by conventional methods. By blending the block copolymer according to the present invention with various plastics, it is possible to impart vibration damping performance to them, and they are preferably used for housings, various parts, etc.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

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

Molecular weight was determined by GPC.

The microstructure was determined by measuring the NMR spectrum and was found to be 64.8 p.
The contents of 3,4 bonds and 1,2 bonds were calculated from the ratio of the peak of 3.4 bonds and 1,2 bonds at 65.8 ppm and the peak of 1,4 bonds at 65.3 ppm.

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

The peak temperature of tan δ was determined by measuring the viscoelastic spectrum using a Rheovibrone (manufactured by Orientech Co., Ltd.).

The loss coefficient (η), which indicates vibration damping performance, is determined by applying vibration to a steel plate with a thickness of 1++n and applying the compound to it using an exciter.
The resonance method was used to measure the degree of resonance of the object being tested.

The measurement frequency was 500 Hz, and the measurement temperature was 40
, 20, O''C, and was used as an index of the breadth of the temperature range showing vibration damping properties.

Example 1, Comparative Example 1 In a pressure-resistant reactor that was dried and purged with nitrogen, 7600 mj2 of cyclohexa was added as a solvent and n-
BuLiO. 2mf, THEDA 0 as vinylation agent
．． After adding 2 ml and raising the temperature to 50°C, styrene monomer 7-5mj2, isoprene monomer 120mj2, and styrene monomer 5rnf were added in this order and polymerized.

The copolymer was recovered by treating the polymerization liquid with methanol. By vacuum drying the obtained copolymer,
A block copolymer (1) was obtained.

The molecular weight of the obtained polymer was 165,000, the molecular weight of the polystyrene block was 9,800, the molecular weight of the polyisoprene block was 145,000, and the total amount of 3.4 bonds and 1.2 bonds was 79.8%.

Moreover, the peak temperature of tan δ was 39.8%.

The obtained copolymer and various isobutylene-based polymers include isobutene and butene-1 copolymers (isobutene/butene-1).
1-butene = approx. 85/15 (wt/wt), molecular weight 1450; Polybutene HV-300 manufactured by Nippon Oil & Chemicals Co., Ltd.), polyisobutylene (Molecular Box 35000, Vistanex LM manufactured by Nippon Petrochemical Co., Ltd.), butyl rubber (isoprene content 1.6 mol %, molecular weight: approximately 350,000 (manufactured by Borisar), and the formulation shown in Table 1 was used to prepare the formulation, and the loss factor was measured. As shown in the results shown in Table 1, when only the block copolymer is used, although it shows high damping performance at 40'C, the loss coefficient is small at 20°C and O''C, and the damping performance is insufficient. It shows that.

In contrast, it can be seen that the assembly of the present invention has a sufficiently high loss coefficient at any temperature and has damping performance over a wide temperature range.

Example 2 A block copolymer (II ) was obtained.

The molecular weight of this product was 120,000, the molecular weight of the polystyrene block was 8,000, the molecular weight of the polyisoprene block was 100,000, the total amount of 3,4 bonds and 1,2 bonds was 73.4%, and the hydrogenation rate was 78.2%. Ta. tanδ
The peak temperature was 36.8°C.

A blend of the copolymer and polyisobutylene (Vistanex LM) was prepared and its loss factor was measured. The results shown in Table 2 indicate that the composition of the present invention exhibits vibration damping performance over a wide temperature range.

Margins below [Effects of the Invention] The present invention provides a vibration damping material that exhibits sufficient vibration damping performance over a wide temperature range.

Claims (1)

[Claims] 1) A block (A) consisting of a vinyl aromatic monomer with a number average molecular weight of 2,500 to 40,000, and isoprene or an isoprene-butadiene mixture, with a number average molecular weight of 10,000 to 200,000, 3,4 bonds and 1,
2 bond content is 40% or more, tan δ is higher than 0℃
or a block (B) in which at least a part of the carbon-carbon double bonds in the chain is hydrogenated, and the bonding form of the block is A.
- Molecular weight is 30,000 to 30,000, expressed as (B-A^)_n or (A-B)_n (n is an integer of 1 or more)
1. A vibration damping composition comprising a block copolymer of 0.0 and an isobutylene polymer.