JP3311052B2 - Damping material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a novel damping material.
More particularly consists of a specific block copolymer, is excellent in vibration damping properties, heat resistance, relates to the weather resistance, damping material having excellent adhesion properties.

[0002]

2. Description of the Related Art Conventionally, for the purpose of preventing the vibration of structural members such as ships, vehicles, automobile parts, home appliances, various machines, building materials, and audio equipment, and the accompanying noise,
2. Description of the Related Art A material having a vibration damping property has been applied to or adhered to the surface or inside of a structural member. Further, in the acoustic diaphragm, it is customary to use a material having a vibration damping property in order to increase the elastic modulus and the internal loss. Materials with vibration damping properties include rubber, asphalt,
Various synthetic resin emulsions and latexes, synthetic resins, etc., as well as graphite, mica,
Carbon black, hillstone, calcium carbonate, talc,
Powders such as clay and those containing natural or synthetic fibers have been used.

[0003]

However, many of the above-mentioned conventional vibration damping materials have a very narrow temperature range for exhibiting the vibration damping property, even if they have a vibration damping property near room temperature. Due to inferior heat resistance, mechanical properties are extremely deteriorated at high temperatures, and there is a drawback that the range of use is limited due to inferior weather resistance.

[0004]

Under such circumstances, the present inventors have conducted intensive studies to develop a vibration-damping material free from the above-mentioned disadvantages. As a result, they have found that a block copolymer represented by the following formula and having a specific glass transition temperature is a damping material having physical properties suitable for the purpose. The present invention has been completed based on such findings. That is, the present invention provides a compound of the formula AB (I) wherein A is styrene, a styrene derivative,
Acrylic acid esters of alcohols, methacrylic acid esters of alcohols having 1 to 3 carbon atoms, acrylamide,
A polymer or copolymer of at least one monomer selected from the group consisting of acrylamide derivatives, methacrylamides, methacrylamide derivatives and vinyl esters of fatty acids having 1 to 12 carbon atoms, wherein B is an acrylate ester, It shows a polymer or copolymer of at least one monomer selected from the group consisting of acrylate derivatives, methacrylate esters and methacrylate derivatives. ), And provides a vibration damping material comprising a block copolymer in which the glass transition temperature of component A is 50 ° C or higher and the glass transition temperature of component B is 30 ° C or lower. is there. In this specification, the glass transition temperature is defined as the value at the center of the bent portion of the glass transition point when the temperature is increased at 10 ° C./min using 10 mg of a sample in differential calorimetry.

[0005] The block copolymer of the present invention basically comprises a component A (polymer portion represented by A) and a component B (polymer portion represented by B) as represented by the above formula (I). ). Here, the A component is styrene,
Styrene derivatives, (meth) of alcohols with 1 to 3 carbon atoms
A (co) polymer of one or more monomers selected from acrylates, (meth) acrylamides, (meth) acrylamide derivatives and vinyl esters of fatty acids having 1 to 12 carbon atoms. Specific examples of the monomer include, for example, styrene; p-methylstyrene; methyl (meth) acrylate; ethyl (meth) acrylate;
N-propyl (meth) acrylate; i-propyl (meth) acrylate; (meth) acrylamide; N, N-dimethyl (meth) acrylamide; N-butyl- (meth) acrylamide; Nt-octylacrylamide; formic acid Vinyl; vinyl acetate; vinyl propionate; vinyl pivalate; vinyl versatate and the like. The component A may be a polymer of one kind of monomer selected from these or a copolymer of two or more kinds of monomers, and it is essential that the glass transition temperature is 50 ° C. or more, It is preferably at least 70 ° C, most preferably at least 90 ° C. The upper limit of the glass transition temperature of the component A is not particularly limited.
50 ° C. or less. If the glass transition temperature of component A is too low than 50 ° C., the mechanical strength of the coating film or sheet of damping materials is lowered, unfavorably also remarkably deteriorated heat resistance.

The component A is a (co) polymer of one or more monomers selected from the above-mentioned monomers. Examples of the component A include polystyrene, a copolymer of styrene and methyl methacrylate, and polymethacrylate. Methyl acrylate is most preferred in terms of mechanical strength and weather resistance of the obtained vibration damping material. The component A is basically a (co) polymer composed of the above-mentioned monomers, but it is difficult to include a small amount of a monomer other than the above as a component of the (co) polymer. There is no particular problem if the amount is about mol% or less. Examples of such monomers include olefins such as ethylene and propylene, halogen-containing monomers such as vinyl chloride, vinyl ether, monomers having a carboxyl group or a salt thereof, quaternary ammonium base-containing monomers, and sulfones. And monomers having an acid or a salt thereof. Above all, it is necessary to copolymerize a small amount of anionic groups such as carboxyl groups and sulfonic acid groups, and to introduce metal cations in the form of salts or coordination compounds into these polymers. It is preferable because the mechanical strength is improved without substantially impairing the vibration.

The method of introducing a cation into a polymer is not particularly limited, but generally, a method of copolymerizing an ionic group in the form of a salt or a method of introducing a ionic group by copolymerization and then introducing a metal Simple substance, formate, acetate, carbonate, sulfate,
Sulfonate, fluoride, chloride, bromide, hydroxide,
Examples include a method in which a metal compound such as an oxide, sulfide, methoxide, or ethoxide is reacted with a polymer in a molten state, in an emulsion, or in a solution. The metal used is not particularly limited, but may be a monovalent metal such as Na, K, Li, or Rb, or may be Mg, Ca, Zn, Cu, Cr, Mn, or F.
Polyvalent metals such as e, Co, Ni, Cd, Pb, and Al have a strong ionic bonding force and are particularly preferable in terms of mechanical strength and heat resistance of the obtained vibration damping material. In addition, ammonium ions can be used in the same manner as metals. The molecular weight of the component A is not particularly limited, but from the viewpoint of the mechanical strength of the obtained vibration damping material, the number average molecular weight (Mn) is 1000 to 5000.
00, preferably 2,000 to 200,000, more preferably 5,000 to 100,000.

On the other hand, the component B of the block copolymer is
A (co) polymer of one or two or more monomers selected from (meth) acrylates and (meth) acrylate derivatives, specific examples of these monomers include Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n- (meth) acrylate
Butyl, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate,
Examples thereof include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate. The component B may be a polymer of one monomer selected from these monomers or a copolymer of two or more monomers, and the glass transition temperature must be 30 ° C. or lower. Is essential, preferably -70 ° C to 10 ° C, most preferably -70 ° C to 0 ° C. The lower limit of the glass transition temperature of the component B is not particularly limited, but is usually -200 ° C or higher. B
If the glass transition temperature of the component is too high than 30 ° C. is not preferable because the vibration damping property of the coating film or sheet of damping materials is reduced.

The component B is a (co) polymer of one or more monomers selected from the above monomers, and the monomers constituting the component B include methacrylates and derivatives thereof. In comparison, acrylic esters and derivatives thereof are more preferable in terms of the vibration damping properties and mechanical strength of the obtained vibration damping material. From such a viewpoint, as the component B, particularly, polyethyl acrylate, n-propyl polyacrylate, i-propyl polyacrylate, and n-butyl polyacrylate are the most preferable components. The component B is basically a (co) polymer composed of the above-mentioned monomers. However, it is difficult to include a small amount of a monomer other than the above as a component of the (co) polymer. There is no particular problem if the amount is about mol% or less. Examples of such a monomer include olefins such as ethylene and propylene, styrenes such as styrene and p-methylstyrene, halogen-containing monomers such as vinyl chloride, vinyl ether, and monomers having a carboxyl group or a salt thereof. ,
Examples include a quaternary ammonium base-containing monomer, a monomer having a sulfonic acid or a salt thereof, and vinyl esters. Among them, copolymerizing a small amount of an anionic group such as a carboxyl group or a sulfonic acid group, and further introducing a metal cation to the polymer in the form of a salt or a coordinator,
It is preferable because the mechanical strength is improved without substantially impairing the damping properties of the obtained damping material.

The method of introducing a cation into a polymer is not particularly limited, but generally, a method of copolymerizing an ionic group in the form of a salt, or a method of introducing a ionic group by copolymerization and then introducing a metal Simple substance, formate, acetate, carbonate, sulfate,
Sulfonate, fluoride, chloride, bromide, hydroxide,
Examples include a method in which a metal compound such as an oxide, sulfide, methoxide, or ethoxide is reacted with a polymer in a molten state, in an emulsion, or in a solution. The metal used is not particularly limited, but may be a monovalent metal such as Na, K, Li, or Rb, or may be Mg, Ca, Zn, Cu, Cr, Mn, or F.
Polyvalent metals such as e, Co, Ni, Cd, Pb, and Al have a strong ionic bonding force and are particularly preferable in terms of mechanical strength and heat resistance of the obtained vibration damping material. In addition, ammonium ions can be used in the same manner as metals. The molecular weight of the component B is not particularly limited, but the vibration damping properties of the obtained vibration damping material,
From the viewpoint of mechanical strength and adhesive strength to a substrate, the number average molecular weight (Mn) is 5,000 to 1,000,000, preferably 100.
00 to 500,000, more preferably 20,000 to 10
0000.

The block copolymer used in the present invention comprises:
As represented by the above formula (I), it is composed of an A component and a B component, and the A component and the B component may be directly bonded,
Alternatively, a form bonded via a sulfur atom, for example, the formula
A-S-B may be used.

There are various methods for producing such a block copolymer, and there is no particular limitation. For example, when radical-polymerizing either one of the components A and B (for example, the monomer of the component A), thiolcarboxylic acid or 2-acetylthioethylthiol,
-Polymerized in the presence of a compound containing a thioester and a thiol group in a molecule such as acetylthiodecanethiol,
The obtained polymer is treated with an alkali such as sodium hydroxide or ammonium to give a polymer having a thiol group at one end, and in the presence of this polymer, a monomer of the other component (for example, Monomer) to obtain the desired block copolymer by radical polymerization is simple and highly efficient,
Most preferred. In this case, a block copolymer in which the component A and the component B are bonded via a sulfur atom is obtained.

In the present invention, the above-mentioned block copolymer alone exerts sufficient performance as a vibration damping material. However, if necessary, rubber, asphalt, various kinds of synthetic resin emulsions and latexes, etc. Or a powder such as graphite, mica, carbon black, hillite, calcium carbonate, talc, clay, or natural or synthetic fiber, glass fiber, metal fiber, or the like. It is also possible to add a plasticizer. Damping materials of the present invention, it is brushing the structural member as unconstrained damping material, or applied by spraying or the like, may be affixed to those formed into a sheet or film shape. Further, it can be used as an intermediate layer between members as a constrained vibration damping material. The thickness of the damping material layer is
There is no particular limitation, and it is appropriately selected according to the purpose. Examples of the base material include various steel plates, metal plates such as aluminum plates and copper plates, plywood, gypsum boards, cement concrete plates, cement mortar plates, slate plates, fiber reinforced resin (FRP) plates, and plastic plates. And the like.

[0014]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. Further, “parts” and “%” represent “parts by weight” and “% by weight” unless otherwise specified.

Example 1 Ethyl acrylate was subjected to radical polymerization in the presence of polystyrene having a thiol group at one end and having a number average molecular weight of 15,000, whereby a block copolymer of a poly (ethyl acrylate) component having a number average molecular weight of 73,000 was obtained. (Copolymer I) was produced. Table 1 shows the properties of the block copolymer. Next, this block copolymer was dissolved in ethyl acetate to obtain a solution having a concentration of 15%. 200 mm
× 200mm 0.8mm thick cold-rolled steel plate brushed,
After drying at room temperature for one day, it was dried in a hot air dryer at 100 ° C. for one hour. The vibration damping properties of the obtained test pieces were 0 ° C, 20 ° C, 50
Evaluation was made by measuring the vibration acceleration level (VAL) at the time of impact vibration at each of the temperatures of ° C and 120 ° C. In other words, two points of the test piece are hung with a thread, and a steel ball collides with the center of the test piece to generate vibration, and the magnitude of the vibration at this time is detected by a pickup fixed to the lower end of the test piece. , Read through a vibration level meter. The difference between the value of the vibration acceleration level and the value of the vibration acceleration level of only the cold-rolled steel sheet was ΔVAL (dB), which was used as a measure of the vibration reduction effect. That is, vibration reduction effect ΔVAL (dB) = VAL of steel sheet only
(DB)-VAL (dB) of the test piece coated with the damping material The results are shown in Table 2.

Examples 2 to 5 Tests were performed in the same manner as in Example 1 except that the block copolymer used was changed to the block copolymer shown in Table 1. Table 2 also shows the results.

Example 6 When dissolving the block copolymer shown in Table 1 in ethyl acetate, 1.5 parts of zinc acetate (carboxyl contained in the polymer) was added to 100 parts of the block copolymer. The test was conducted in the same manner as in Example 1 except that Zn ^{2+ (} about 1.0 equivalent to the amount of the group) was added at the same time, and the ^mixture was heated and stirred at 60 ° C. for 2 hours. Table 2 also shows the results.

Example 7 Instead of the block copolymer used in Example 1,
Using 100 parts of the block copolymer shown in Table 1 and 1.3 parts of calcium oxide (approximately 1.0 equivalent of Ca ²⁺ based on the amount of carboxyl groups contained in the polymer), and a roll at 180 ° C. The test was conducted in the same manner as in Example 1 except that the kneading was carried out for 10 minutes. Table 2 also shows the results.

Comparative Examples 1 to 3 Tests were carried out in the same manner as in Example 1 except that the polymers or copolymers shown in Table 1 were used instead of the block copolymers. Table 2 also shows the results.

Examples 8 to 12 Using the block copolymers shown in Table 1, a thickness of 0.2 m was used.
m, and the film was sandwiched between two cold-rolled steel sheets having a thickness of 0.6 mm, and was hot-pressed at a temperature of 120 ° C. to be integrated to produce a restrained damping steel sheet. With respect to this steel sheet, the loss factor was measured at 20 ° C. and 50 ° C. by the vibration lead method (cantilever beam, resonance method). The results are shown in Table 3.

Example 13 The same procedure as in Examples 8 to 12 was carried out except that the block copolymer shown in Table 1 was replaced with a block copolymer in which Zn ²⁺ was introduced in the same manner as in Example 6. Tested. Table 3 also shows the results.

Example 14 The same procedure as in Examples 8 to 12 was carried out except that the block copolymer shown in Table 1 was replaced with a block copolymer in which Ca ²⁺ was introduced in the same manner as in Example 7. Tested. Table 3 also shows the results.

Comparative Examples 4 to 6 A vibration-damping steel sheet was prepared in the same manner as in Example 5 except that the polymers or copolymers shown in Table 1 were used instead of the block copolymer. In Comparative Examples 4 and 5, the polymer flowed out during hot pressing, and no damping steel sheet was obtained. In Comparative Example 6, a damping steel sheet could be obtained, but the steel sheet did not show sufficient damping properties.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

The vibration damping material of the present invention has excellent vibration damping properties, and
Its industrial meaning is extremely large because it has a wide temperature range showing vibration damping properties, and is excellent in heat resistance, adhesion to substrates, and weather resistance.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hitoshi Maruyama 1621 Sazu, Kurashiki City, Okayama Prefecture Inside Kuraray Co., Ltd. Inventor Shinya Ishikawa 1-13-13-112 Haramachida, Machida-shi, Tokyo (56) References JP-A-63-314223 (JP, A) JP-A-56-67380 (JP, A) (58) Fields investigated Int.Cl. ⁷ , DB name) C08F 293/00 F16F 15/02

Claims (2)

(57) [Claims] 1. A formula AB wherein A is styrene, a styrene derivative, and has 1 to 3 carbon atoms.
Acrylic acid esters of alcohols, methacrylic acid esters of alcohols having 1 to 3 carbon atoms, acrylamide,
A polymer or copolymer of at least one monomer selected from the group consisting of acrylamide derivatives, methacrylamides, methacrylamide derivatives and vinyl esters of fatty acids having 1 to 12 carbon atoms, wherein B is an acrylate ester, It shows a polymer or copolymer of at least one monomer selected from the group consisting of acrylate derivatives, methacrylate esters and methacrylate derivatives. ), Wherein the component A has a glass transition temperature of 50 ° C. or higher and the component B has a glass transition temperature of 30 ° C. or lower . 2. The vibration damping material according to claim 1, comprising a block copolymer in which the component A and the component B are bonded via a sulfur atom .