WO2017094201A1

WO2017094201A1 - Composite material and method for improving damping property thereof

Info

Publication number: WO2017094201A1
Application number: PCT/JP2015/084459
Authority: WO
Inventors: Andrei A. GUSEV; Peter J. HINE; Anthony P. UNWIN; Ian M. Ward; Masato Fujita; Eiji Tanaka
Original assignee: Mitsubishi Chemical Holdings Corporation; Eth Zurich; University Of Leeds
Priority date: 2015-12-02
Filing date: 2015-12-02
Publication date: 2017-06-08
Also published as: WO2017094266A1

Abstract

The present invention has allowed to provide a composite material including three components of at least two types of resin and a filler, which has realized compatibility between damping property and stiffness, the usually mutually exclusive properties, by increasing the peak value and peak temperature of the loss factor (tan δ) as a result of determining a specific contents of the two types of resin and of using a filler with an aspect ratio of less than 50.

Description

DESCRIPTION

COMPOSITE MATERIAL AND METHOD FOR IMPROVING DAMPING

PROPERTY THEREOF

TECHNICAL FIELD

[0001]

The present invention relates to a composite material having damping property. In particular, the invention relates to a composite material preferably used in the field of construction, civil engineering, vehicles, transportation, home electronics, information devices, sporting goods, toys, and so forth, and particularly used as a constituent material of a component requiring damping property, such as components of transport aircrafts, precision electronic equipment, audio equipment. Further, the invention relates to a method for improving the damping property of the composite material.

BACKGROUND ART

[0002]

Molded articles of thermoplastic resin are widely used for construction and civil engineering materials, cars and vehicles, components of home electronics and information devices, sporting goods, commodities, toys, and so forth. As molded articles of thermoplastic resin have moldability well-balanced with physical properties and excellent cost performance, they are used for a wide range of applications. Such molded articles are manufactured as articles from one type of resin, composite articles from two or more types of resins, or composite articles combined with components such as particles, dyes, pigments, plasticizers, and stabilizers, in a composition designed according to their intended use.

[0003]

In recent years, while reducing weight of vehicles and transports such as cars is demanded in order to improve energy efficiency, lowering noise and vibration therein are also demanded. Although it is demanded to replace steel plate with resin in order to reduce weight, reducing weight and lowering noise and vibration are difficult to be compatible with each other, and vibration control of resin composite materials is expected as a countermeasure. Lowering noise and vibration is achieved by suppressing vibration that is an origin of noise. Similarly, reducing noise and vibration resulting from office machines and home electronic appliances that have gotten bigger, reducing sound generated in buildings such as standard homes and offices, and external noise are demanded. In addition, audio equipment requires reproducing clear sound by lowering the vibration of the housing and relevant components thereof.

[0004]

In order to answer to these demands, there are proposed, as a material having damping property, a block copolymer containing vinyl bonds (Patent Document 1), a conjugated diene compound based copolymer (Patent Document 2), a polyphenylene ether based resin composition (Patent Document 3), a resin composition in which main components are polyamide and polyphenylene to which is added a conjugated diene-aromatic compound polymer (Patent Document 4), a composition including cross-copolymerized olefin-aromatic vinyl compound-diene copolymer (Patent Document 5), a resin composition including a cross-linked polyurethane resin (Patent Document 6), a composition including a styrene based resin (Patent Document 7), and so forth.

A composition in which a resin composition contains filler is also proposed (Patent Documents 8 to 13).

Further, a discussion is disclosed on the loss factor behavior of a numerical model in which a spherical additive having a coating layer consisting of a

viscoelastic polymer is combined into a solid polymer (Non-Patent Document 1). [0005]

On the other hand, even for materials having damping property, when they are utilized, for example, as construction materials, stiffness is also an important factor, and the development of a material having sufficient damping property, as well as stiffness sufficient to be used in construction, is required.

PRIOR ART REFERENCES

Patent Documents

[0006]

PD 1: Japanese Laid-open Patent Publication No. H5-279543

PD 2: Japanese Laid-open Patent Publication No. H6-41443

PD 3: Japanese Laid-open Patent Publication No. 2006-57107

PD 4: Japanese Laid-open Patent Publication No. H9-279012

PD 5: Japanese Laid-open Patent Publication No. 2002-265722

PD 6: Japanese Laid-open Patent Publication No. H9- 188766

PD 7: Japanese Laid-open Patent Publication No. HI 0-67901

PD 8: Japanese Laid-open Patent Publication No. H7-97493

PD 9: Japanese Laid-open Patent Publication No. 2000-109711

PD 10: Japanese Laid-open Patent Publication No. H7-118448

PD 11: Japanese Laid-open Patent Publication No. H9-40812

PD 12: Japanese Laid-open Patent Publication No. H9-40840

PD 13: Japanese Laid-open Patent Publication No. H2012-25830

Non-Patent Documents

[0007]

NPD 1: Macromolecules.vol.42, No 14, 2009. P5372-5377

DISCLOSURE OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION [0008]

The present invention has been conducted in view of the above description, and is intended to provide a composite material in which damping property and stiffness, the usually mutually exclusive properties, are compatible with each other. MEANS FOR SOLVING THE PROBLEMS

[0009]

The inventors have discovered, after intensive investigations to resolve the above described issues, that a composite material of three components including at least two types of resins combined with a filler, the content of the two types of resins being determined to be specific, and the filler having an aspect ratio of less than 50, can implement a sufficiently high stiffness of the composite material, and increase the peak value of loss factor (tan δ) at a target temperature. In addition, it has been found that in spite of increase in the peak value of the loss factor (tan δ), the stiffness has not been reduced in comparison to the stiffness of the main resin component, and the present invention has been achieved.

[0010]

Thus, the summary of the present invention is as follows:

(1) A composite material comprising at least three components of a component A, a component B, and a component C,

the component A being a thermoplastic resin,

the component B being an elastomer having a glass transition temperature (Tg) different from a glass transition temperature (Tg) of the component A, and

the component C being a filler with an aspect ratio of less than 50,

wherein a volume ratio of the component A and the component B in the composite material fulfills A > B,

the component B is contained in the composite material in an amount of less than 10% by volume and does not form a continuous phase,

the component C is contained in the composite material in an amount of not less than 15% by volume,

a peak value of an enhanced loss factor (tan δ), with the latter defined as the difference between the values of the loss factor (tan δ) of the composite material and the loss factor (tan δ) of the component A alone, is not less than 0.04, and

a peak temperature of the enhanced loss factor (tan δ) is higher by not less than 15°C than the glass transition temperature of the component B.

(2) A composite material comprising at least three components of a component A, a component B, and a component C,

the component A being a thermoplastic resin,

the component C being a filler with an aspect ratio of less than 50,

there are two peaks of a loss factor (tan δ) originated from the component B of the composite material such that a peak temperature at higher temperature is larger by not less than 15°C than a peak temperature at lower temperature. (3) The composite material according to (1) or (2), wherein the component A is an amorphous resin.

(4) The composite material according to any one of (1) to (3), wherein the component C is a filler with an aspect ratio of less than 5.

(5) The composite material according to any one of (2) to (4), wherein a change rate of shear modulus (G') taken at the higher peak temperature of the loss factor (tan δ) originated from the component B of the composite material is not less than 90% from that of the component A alone taken as the same temperature.

(6) The composite material according to any one of (1) to (5), wherein the component B is submicron-dispersed into the component A in the composite material.

(7) The composite material according to any one of (1) to (6), wherein at least a portion of the component C is coated with component B.

(8) A method for improving damping property of a composite material including a component A, a component B and a component C, the method comprising the step of

mixing the component A which is a thermoplastic resin, the component B which is an elastomer having a glass transition temperature (Tg) different from a glass transition temperature (Tg) of the component A, and the component C which is a filler with an aspect ratio of less than 50,

wherein, a volume ratio of the component A and the component B in the composite material fulfills A > B,

the component B is contained in the composite material in an amount of less than 10% by volume and does not form a continuous phase, and

the component C is contained in the composite material in an amount of not less than 15% by volume.

EFFECT OF THE INVENTION [0011]

The present invention can provide a composite material in which high level damping property and high stiffness, mutually exclusive properties, are compatible with each other, and which is industrially extremely valuable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]

Figure 1 is a graph depicting temperature change in the loss factor (tan δ) of the composite materials of Examples 1 to 4, and Comparative Example 1.

Figure 2 is a TEM image of the composite material where the component B is submicron-dispersed into the component A (Photograph).

MODE FOR CARRYING OUT THE INVENTION

[0013]

Although embodiments of the present invention will now be explained in detail, the present invention is not limited to the illustrations and embodiments and so forth described below, and any modification can be made without departing the scope of the spirit of the present invention.

[0014]

The composite material according to the present embodiments is a composite material including at least a component A, a component B, and a component C, as will be explained in detail below, and at an operating temperature region of the composite material, the peak value of an enhanced loss factor (tan δ), with the latter defined as a difference between the values of loss factor (tan δ) of composite material and the loss factor (tan 6) of the component A alone, is not less than 0.04, the peak temperature of the enhanced loss factor (tan δ) shifts to a temperature region higher by not less than 15°C than the glass transition temperature of the component B due to a composite effect of the component C.

Also, the composite material according to the present another embodiments is a composite material including at least a component A, a component B, and a component C, as will be explained in detail below, and at an operating temperature region of the composite material, the peak value of an enhanced loss factor (tan δ), with the latter defined as a difference between the values of the loss factor (tan δ) of the composite material and the loss factor (tan δ) of the component A alone, is not less than 0.04, there are two peaks of an enhanced loss factor (tan δ) that a peak temperature at higher temperature is higher by not less than 15°C than the glass transition temperature of the component B due to a composite effect of the component C.

In addition, in the step of blending of the component A, the component B and the component C, the component B is submicron-dispersed into the component A in the composite material by the inclusion of the specific component C in not less than 15% by volume. Accordingly, the composite material according to the present embodiments can render damping property and stiffness, the usually mutually exclusive properties, compatible with each other.

The components A to C composing the composite material according to the present embodiments will now be explained in sequence.

[0015]

In the present invention, when the component A and the component B include two or more types of resins, these resins may be included as simple mixtures, or as a copolymer produced by the polymerization of the monomers consisting of each of the resins. This copolymer may be any one of a block copolymer, a random copolymer, and a graft copolymer. Two or more types of the same resin with different properties such as molecular weights, branching structures can also be used in combination.

[0016]

The component A is a thermoplastic resin, and a component that mainly gives stiffness to the composite material according to the present embodiment. As will be described later, due to the volume ratio of component A > component B in the composite material, it is a component that plays the role of matrix in the composite material. Therefore, a thermoplastic resin can be selected so that the composite material has a stiffness appropriate to a demanded case, and the resin can be used without any particular limitation.

As thermoplastic resins, many crystalline or non-crystalline resins are used for various use purposes, which include addition-polymerized polymers, such as polyolefins (polyethylene (PE), polypropylene (PP)), polystyrene (PS), polyvinyl chloride, acrylic polymers, ABS resins (acrylonitrile-butadiene-styrene), and fluororesins, condensation polymers including general-purpose engineering plastics, such as polyesters, polyamides (PAs), polyurethanes (PUs), polycarbonates (PCs), polyacetals, and denatured PPEs (polyphenyl ethers). For example, PP, ABSs, PAs, PUs, and so forth are often used as materials for automobile use. Notably, polyolefins are representatively used, and specifically include polymers or copolymers of olefin, and more specifically, polyethylene, polypropylene, polymethylpentene, and polybutene. Obviously, other thermoplastic resins can also be used.

[0017]

The component A is composed of one type of single polymer of thermoplastic resin or copolymer of two or more types of monomer of thermoplastic resin. For the case of copolymer, any methods including graft copolymerization, random copolymerization, and block copolymerization can be used.

Further, the component A may be an amorphous resin.

[0018]

The composite material according to the present embodiment is envisioned to be used as a material for construction, automobile, or other use, in which the component A preferably has a high stiffness. For example, the storage shear modulus (Storage Modulus) G' of the component A may be 0.5 GPa or more, 1.0 GPa or more, 1.5 GPa or more at 50°C, and the value can be selected on demand.

The storage shear modulus G' can be measured by the method as will be described below.

[0019]

The molecular weight of the thermoplastic resin of the component A is, depending on the structure and the molding method thereof, usually 10,000 or more as a number average molecular weight, and may be 15,000 or more, or 20,000 or more. Further, it is usually 2,000,000 or less, and may be 1 ,000,000 or less, or 700,000 or less. The molecular weight within these ranges is preferable in that the resin has a good moldability, and a sufficient strength as a molded article.

[0020]

The content of the component A in the composite material according to the present embodiment is usually 20% or more by the volume ratio to the composite material, and may be 25% or more, or 30% or more, and is usually 90% or less, and may be 80% or less, 70% or less, or 60% or less.

Further, in connection with the component B as will be described below, the volume ratio of the material fulfills A > B, and the component A functions as a matrix in the composite material. When such a component ratio is fulfilled, a composite material with an excellent stiffness can be realized. [0021]

In the present embodiment, the component B is an elastomer having the glass transition temperature (Tg) different from the glass transition temperature (Tg) of the component A.

The elastomer in the present invention represents a polymer having rubberlike elasticity (entropy elasticity) in a specific temperature range (for example, at least one temperature from -30°C to 80°C). In the present embodiment, selected is an elastomer having appropriate peak temperature of the loss factor (tan δ) depending on the operating temperature of a composite material. For example, if the operating temperature of a composite material is near the room temperature, used are elastomers having a peak temperature of the loss factor (tan5) from -30°C to near the room temperature. When the peak temperature is out of this temperature range, a sufficient damping property cannot be obtained. When the operating temperature of a composite material is 0°C or lower, elastomers having a peak temperature of the loss factor (tan6) of 0°C or lower can also be used, while when the working temperature of the composite material is the room temperature or higher, elastomers having a peak temperature of the loss factor (tan6) being the room temperature or higher can be used.

Polymers having properties of such elastomers include, typically, a conjugated diene polymer, a copolymer of addition polymerized monomers copolymerizable with a conjugated diene or the like. The conjugated diene includes, for example, butadiene, isoprene or the like, and the copolymerizable addition polymerized monomers include aromatic alkenyl compounds (such as styrene), acrylic ester monomers, and/or methacrylic acid ester monomers and other monomers. Polymers cross-linked with these polymers can also be used. Further, urethane elastomers, silicon elastomers and fluorine elastomers or the like can also be used. Among the above-mentioned, elastomers having an appropriate peak temperature of the loss factor (tan6) according to the operating temperature of the composite material are selected. In obtaining the composite material of the present embodiment by using the elastomers above, the polymers are not necessarily used alone, but the polymers in the form of being conjugated with other polymers can also be used for the purpose of easiness of conjugating operation and improving dispersibihty. In that case, what is called a thermoplastic elastomer is a typical example thereof.

[0022]

Specific examples of the thermoplastic elastomer include styrene-isoprene block copolymers, styrene-butadiene block copolymers, polystyrene thermoplastic elastomers such as partially hydrogenated copolymers of the aforementioned copolymers, polyolefin-based thermoplastic elastomers in which ethylene-propylene- diene rubber (EPDM) has been fine dispersed in polypropylene and the EPDM is partially or entirely cross-linked, and polyurethane-based thermoplastic elastomers obtained from reaction of polyester or polyether with isocyanate. In addition, vinyl- chloride-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers can be used. These elastomers may be prepared by any polymerization method, (such as emulsion polymerization, solution polymerization, bulk polymerization) with any catalyst (for example, a peroxide, trialkylaluminum, lithium halide, a nickel catalyst, a Ziegler - Natta catalyst and a metallocene catalyst).

Further, usable polymers also include those having various degrees of cross- linkage, diene-based polymers having microstructures of various ratios (such as cis structure, trans structure, and a vinyl group). As for copolymers, various copolymers such as random copolymers, block copolymers consisting of an aromatic alkenyl compound (such as styrene) and a diene-based monomer and graft copolymers obtained by radical polymerizing an aromatic alkenyl compound (such as styrene), an acrylic acid ester monomer and/or a methacrylic acid ester monomer in the presence of a diene polymer, are all usable. In addition, a partially modified rubberlike substance, such as hydroxyl or carboxy terminally-modified polybutadiene, may be used. Like polyolefin-based thermoplastic elastomers, it is also possible to prepare elastomers by kneading two or more polymers. The composite material according to the present embodiment, as will be described in detail, is characterized in that the peak temperature of the loss factor (tan δ) shifts to the temperature side higher than the peak temperature of the loss factor (tan δ) of the component B alone due to a composite effect of the component C, and the peak value increases. Therefore, the component B has to be an elastomer having the glass transition temperature (Tg) different from the glass transition temperature (Tg) of the component A.

[0023]

In the composite material according to the present embodiment, the

component B is contained in the composite material in an amount of less than 10% by volume, and does not form a continuous phase. Further, as above described, the relation of the volume ratio between the component A and the component B fulfills A > B. For example, as depicted in Figure 2, while the component A forms a matrix as a continuous phase, the component B having a lower volume ratio does not form a continuous phase as a result of dispersing into the component A. Thus, the component B is submicron-dispersed into the component A in the composite material. Due to such a structure, a composite material can be realized that sufficiently exhibits the stiffness property possessed by the component A and has an improved damping property. The term "submicron-dispersed" herein means a dispersed state in which the size in the axial direction along which the domain of the component B is the smallest is less than 1 μηι. Accordingly, a fiber form of equal to or longer than 1 μπι in one axial direction, and a lamella form wider than or equal to 1 μηι in two axial directions are considered to be submicron-dispersed so long as they are shorter than Ιμιη in the other axial directions. The submicron-dispersion of the component B into the component A causes the increase in the peak temperature of the loss factor (tan δ) of the component B of which circumference is constrained within a thickness of less than 1 μηι, and simultaneously, the increase in the boundary area between the component A and the component B, and the efficiency of vibrational absorption in the composite material is expected to be improved.

When the component B is contained in the composite material in an amount of 10% by volume or more, the stiffness at temperatures equal to or higher than the glass transition temperature (Tg) of the component B in composite material significantly deteriorates. In particular, when the component B is a non-crystalline polymer material, the deterioration of stiffness at a temperature equal to or higher than the glass transition temperature (Tg) is particularly large, and the compatibility of damping property with stiffness to be realized by the present invention is impossible. Accordingly, lowering the volume ratio of the component B is effective in order to keep the stiffness of the composite material as high as possible at temperature regions equal to or higher than glass transition temperature (Tg) of the component B.

[0024]

In order to obtain a composite material having damping property at an ambient temperature by using the above described elastomer, it is preferable to use a copolymer having a segment with a glass transition temperature (Tg) equal to or less than the ambient temperature and a segment with a glass transition temperature (Tg) equal to or higher than the ambient temperature. Block copolymerized elastomers having an acryl-based, polyurethane-based, polystyrene-based, polyester-based, or polycarbonate-based segment and a gum-based segment are preferably used in view of their superior cost balance of the composite material.

[0025]

The component B is composed of a mixture including one type or two or more types of these polymers, and also a mixture including, for example, two or more types of polymers having different molecular weights and branching structures while their monomelic forms are the same.

[0026]

The molecular weight of the elastomer used as the component B is not particularly limited. In addition, in order for the component B not to form a continuous phase, it is preferable that the difference the melt viscosity between the component A and the component B at their mold temperatures is large.

[0027]

The elastomer of the component B usually has at least one glass transition temperature (Tg) lower than the operating temperature region of the composite material. The glass transition temperature (Tg) of the component B higher than the temperature at which the composite material according to the present embodiment is used may result in an insufficient damping property. The glass transition temperature (Tg) of the component B is preferably lower by more than 15°C than the main operating temperature. For example, when used at 120°C, the elastomer of the component B may have at least one glass transition temperature (Tg) at or below 105°C, when used at 65°C, it may have at least one glass transition temperature (Tg) at or below 50°C, when used at 45°C, it may have at least one glass transition temperature (Tg) at or below 30°C, and when used at 25°C, it may have at least one glass transition temperature (Tg) at or below 10°C.

[0028]

On the other hand, the lower limit value of the glass transition temperature (Tg) is not particularly limited, and may be usually -60°C or more, -40°C or more, or -20°C or more.

In addition, an elastomer having at least one glass transition temperature (Tg) is acceptable, and a co-polymerize¾ resin Having at least two glass transition temperatures (Tg) is also acceptable. Moreover, a resin having a different glass transition temperature (Tg) may be used in combination.

[0029]

The component B is a component that gives damping property to the composite material, and is characterized in that a peak of the loss factor (tan δ) in viscoelastic behavior exists. The peak of loss factor (tan δ) usually exists at almost the same position as the glass transition temperature (Tg).

Specifically, the component preferably has a peak of the loss factor (tan δ) within the range of the operating temperature of the composite material, and when the loss factor (tan δ) originated from the component B of the composite material, that is an enhanced loss factor (tan δ), at the peak temperature is 0.04 or more, preferably 0.05 or more, more preferably 0.07 or more, still more preferably 0.08 or more, and in particular 0.1 or more, an excellent damping property is realized. In addition, although the upper limit of the enhanced loss factor (tan δ) is not defined, it is usually 2 or less, and may be 1.6 or less in the resins generally used as raw materials. When the loss factor (tan δ) exceeds 2, the balance between the strength and the damping property of the composite material may be disrupted, and in particular, the deterioration of the strength may significantly narrow the range of use as a material.

The enhanced loss factor (tan δ) can be measured by the method of the examples as will be described below.

[0030]

In order to realize a structure in which the component B is submicron- dispersed into the component A in the composite material, it is important that the content of the component B in the composite material according to the present embodiment fulfills the volume ratio of A > B in relation to the component A, and is contained the composite material in an amount of less than 10% by volume of the composite material. In addition, the component B is at the volume ratio to the composite material of usually 0.1% or more by volume, and may be 0.2% or more, 0.4% or more, and 8% or less, 7% or less, or 5% or less. When the content of the component B is not less than 10% by volume, the degradation of the stiffness of the composite material at temperature regions equal to or higher than the glass transition temperature (Tg) of the component B becomes large, resulting in incompatibility between damping property and stiffness. When the volume ratio of the component B to the composite material is as small as less than 10%, less than 8%, and in particular, less than 7% by volume, the component B can be submicron-dispersed into the component A with the aid of the component C as will be described later. As a result, not only the peak temperature of the loss factor (tan δ) of the composite material shifts, due to a composite effect of the component C, from the peak temperature of the loss factor (tan δ) of the component B alone to the higher temperature side, but also the peak value increases in proportion to the volume fraction of component C, which can improve the damping property of the composite material and realize the compatibility between the damping property and the stiffness.

[0031]

In the present embodiment, the component C is a filler having an aspect ratio of less than 50, and it may be a plate-like, cylindrical, or spherical shape, or indefinite shape such as an amorphous shape. In order for the surface of the composite material to be smooth, the aspect ratio of the filler of the component C is preferably less than 30. Moreover, the aspect ratio is preferably less than 5, or may be less than 4, less than 3, or less than 2. In this manner, when the filler having an aspect ratio of less than 50 is contained in the composite material, not only the peak temperature of the loss factor (tan δ) of the composite material shifts from the peak temperature of the loss factor (tan δ) of the component B alone to the higher temperature side, but also the peak value increases in proportion to the volume ratio of component C, which can significantly improve the damping property of the composite material.

[0032]

As the filler of the component C, any known materials which have an aspect ratio of less than 50 can be used. The fillers include inorganic fillers such as glass (soda glass, highly refractive index glass (BaTi glass)), silica, calcium carbonate, titanium oxide, barium sulfate, alumina, aluminum hydroxide, zeolite, molecular sieve, mica, kaolin, talc, clay, carbon black, and cross-linked organic fillers such as styrene-based beads, acryl-based beads, melamine-based beads. One of these fillers may be used alone or two or more may be used in any combination of any appropriate ratio.

The filler may also be surface-treated by known surface modifiers. In addition, hollow fillers having a cavity therein, shell core fillers having another component therein, or porous fillers may be used.

[0033]

The average particle diameter of the filler (usually the average particle diameter of the primary particle and for a clumpy shaped filler, the average particle diameter of the secondary particle) is not particularly limited, and usually 1 μιη or more, and may be 10 μπι or more, may be 15μπι or more, or 20μπι or more, and is usually ΙΟΟΟμπι or less, and may be 500μπι or less, or ΙΟΟμηι or less.

When the particle diameter of the filler is too small, the vibration control effect of the present invention tend to be small due to the excessive smallness, and when the diameter is too large, not only insufficient damping property is obtained, but also the composite material tends to be brittle.

The average particle diameter of the filler is measured by using a laser diffraction/scattering particle size analyzer according to JIS Z8825-l(2001).

Specifically, for example, ParticaLA-950V2, the laser diffraction/scattering particle size analyzer from HORIBA, Ltd. is used. Using the 50 % integral value (based on volume) of the distribution of equivalent particle diameter of the measured particles, the average particle diameter (d50) is defined. For a bar-like filler, such as glass fiber and whisker, of which average particle diameter based on similar measurements was not described, in the case that the major and minor diameters were clearly determined, for example, from the aspect ratio, cylindrical shape was supposed in order to obtain its volume, from which shape the diameter of a supposedly exact sphere was calculated by using the formula V^d³/6, and the diameter d was defined as the average particle diameter. For example, in the case of glass fiber with a diameter of ΙΟμηι and an aspect ratio of 20, the average particle diameter is determined to be 31μπι.

[0034]

The content of the component C in the composite material of the present embodiment is usually 15% or more by volume ratio, and may be 20% or more, 25% or more, or 30% or more. On the other hand, the upper limit is not particularly limited, and the damping property of the composite material improves, although the combination of a larger amount of the filler of the component C into the composite material tends to be brittle. The content is 90% or less by volume ratio, and may be 80% or less, 70% or less, or 50% or less. In the case of high volume ratios above 70%, in which brittleness is a concern, lamination of a layer with a volume ratio less than or equal to 30 % or another material can improve the brittleness.

[0035] In the present embodiment, the circumference of the filler of the component C may coated with the component B. The filler surface may be partially or entirely coated. As a coating method, known methods can be used such as a method of blending component B and component C, or a method of coating the component C, by using a method such as the spray method, with the component B liquefied by heating or dispersing.

[0036]

In the composite material according to the present embodiment, within in the spirit of the present invention, anti-weathering agents, light-resistant agents, antistatic agents, lubricants, light-blocking agents, antioxidants, fluorescent brightening agents, thermal stabilizers, flame retardants, ultraviolet absorbers, plasticizers, surfactants, and coloring agents such as dyes and pigments may be combined.

[0037]

The composite material according to the present embodiment including at least above described component A, the component B, and the component C has an excellent damping property, i.e., the peak value of an enhanced loss factor (tan δ), with the latter defined as the difference between the values of the loss factor (tan δ) of the composite material and the loss factor (tan δ) of the component A alone, is not less than 0.04 at operating temperature regions of the composite material, and the peak temperature of the enhanced loss factor (tan δ) is higher by not less than 15°C than the glass transition temperature of the component B.

Also, the composite material according to the present another embodiment including at least above described component A, the component B, and the component C has an excellent damping property, i.e., the peak value of the enhanced loss factor (tan δ), with the latter defined as the difference between the values of the loss factor (tan δ) of the composite material and the loss factor (tan δ) of the component A alone, is not less than 0.04 at operating temperature regions of the composite material, there are two peaks of an enhanced loss factor (tan δ) such that a peak temperature at higher temperature is larger by not less than 15°C than a peak temperature at lower temperature.

The term "peak value of an enhanced loss factor (tan δ)" means the difference between the peak value of the loss factor (tan δ) of the composite material and the value of the loss factor (tan δ) of the component A taken at the same temperature. That is, "peak value of an enhanced loss factor (tan δ)" means peak value of a loss factor (tan δ) originated from the component B, not originated from other

components, and the peak exists in a higher temperature region relative to the peak temperature of component B. The term "peak temperature of the (enhanced) loss factor (tan δ)" means a temperature indicating the peak of the (enhanced) loss factor (tan δ).

Thus, it is intended that combining the component C leads to increase in the peak temperature and the peak value of the loss factor (tan δ) of the component B combined in order to exhibit damping property. Accordingly, the composite material according to the present embodiment shows an effect improving its performance as a composite material by combining the component C.

In the case that two or more peaks of the enhanced loss factor (tan δ) of the composite material exist, it is enough that at least one peak satisfies the above requirement.

[0038]

For example, in the comparative example in Figure 1 which does not contain any filler, a single peak of the loss factor (tan δ) exists in a region somewhat higher than the glass transition temperature (Tg) of the component B. However, in the examples with the fillers, the peaks of the loss factor (tan δ) shift to the higher temperature side, and the peak values of the loss factor (tan δ) increase. The peak value of an enhanced loss factor (tan δ) is a value calculated from this shifted peak to the higher temperature.

[0039]

The inventors speculate that the reason of the excellent damping property of the composite material according to the present embodiment is as follows.

By adding a relatively minor amount of component B to the component A which functions as a matrix, adding a relatively large amount of the filler of component C of 15% by volume, and well kneading them using a twin screw extruder, the component B is submicron-dispersed into the component A. As a result of designing such a miscibility between the component A and the component B and the kneading condition, an anomalous structure in which the component B is submicron-dispersed contributes to the novel emergence of an additional peak of the loss factor (tan δ) in the higher temperature side, with increased peak value of the loss factor (tan δ), which is not proportional to the content ratio of the component B.

Figure 2 shows a TEM image of the composite material where the component B is dispersed to form small-flat domains (a thickness of the domain is sub-micron scale) into the component A (matrix) located near the component C (particle). The domains are indicated by arrows in Figure 2.

[0040]

In the operating temperature region of the composite material, the peak value of the enhanced loss factor (tan δ) may be 0.05 or more, 0.06 or more, 0.07 or more, or 0.08 or more.

In addition, the peak temperature of the loss factor (tan δ) originated from the component B of the composite material may be higher by 15°C or more, 17.5°C or more, or 20°C or more than the peak temperature of the loss factor (tan δ) of the component B alone.

Further, a change rate of storage shear modulus (G') taken at the higher peak temperature of the loss factor (tan δ) originated from the component B of the composite material may be not less than 90%, not less than 100%, not less than 110%, or not less than 120% from that of the component A alone taken at the same temperature.

Also, a change rate of storage shear modulus (G') taken at the peak

temperature of the enhanced loss factor (tan δ) may be not less than 90%, not less than 100%, not less than 110%, or not less than 120% from that of the component A alone taken at the same temperature.

In this case, storage shear modulus (G') of the enhanced loss factor (tan δ) and storage shear modulus (G') of the component A should be taken at the same temperature.

[0041]

Production methods for the composite material according to the present embodiment are not particularly limited. For example, the material can be produced by a method which includes a step of mixing component A, component B and component C to obtain a mixture and a step of melting and kneading the mixture at a temperature at which melting and kneading can be performed, and a method which includes a step of blending component B and component C to obtain a mixture, or a step of coating the component C, by a method such as the spray method, with the component B liquefied by heating or dispersing to obtain a coated material, and a step of melting and kneading the mixture or the coated material and the component A at a temperature at which melting and kneading can be performed.

Specifically, for example, the material can be produced by a method for improving the damping property of the composite material including the component A, component B and component C, including a step of blending the component A being a thermoplastic resin, the component B being an elastomer having a glass transition temperature (Tg) different from the glass transition temperature (Tg) of the component A, and component C being a filler with an aspect ratio of less than 50, such that the volume ratio thereof in the composite material fulfills A > B, the component B is contained in the composite material in an amount of less than 10% by volume, and the component C is contained in the composite material in an amount of not less than 15% by volume, wherein the component B does not form a continuous phase in the composite material.

[0042]

For melting and kneading of component A, component B, and component C, all of the components can be simultaneously added for blending, or a blending sequence for each of the components can be determined. For blending the components to be mixed, tumblers, mixers, blenders can be used, and as for kneading tools used in melting and kneading, single- or twin-screw melt extruders, kneading rolls can be used.

Temperature for melt and knead is not particularly limited so long as it is a temperature at which melting and kneading can be performed.

Kneading is preferably performed under a condition that the component B is sheared so that it is submicron-dispersed into the component A in the composite material. For this purpose, it is effective that the component C is contained in the composite material in an amount of not less than 15% by volume. In addition, as for the knead temperature, it is preferable that kneading is performed at a

temperature at which both the component A and the component B are melted, and moreover, kneading is performed in temperature regions higher than a temperature at which the melt viscosity of the component B is higher than that of the component A.

[0043]

The composite material obtained by melting and kneading can be molded in any desired forms by extrusion molding, injecting molding, press molding, calendar molding, mill roll shaping, etc. The composite material according to the present embodiment can be used as-is as a molded article, but the molded article can also be used as a vibration controlling material attached to or sandwiched between steel plates, glasses, or other plastic articles.

[0044]

The vibration controlling material obtained by molding the composite material according to the present embodiment can be used for various use

applications, as building material including wall material, floor material, ceiling material having vibration controlling, sound controlling, and sound insulating effects, as a material for enhancing quietness by lowering vibration and lowering noise, used in partitions for dividing room, refrigerators, washing machines, driers, cleaners, air- conditioning equipment, etc., as a material for enhancing quietness for use in vehicles such as cars, ships, and aircrafts, and as a vibration isolating material used for mattings or housings of vibrating electronic equipment, office machines, and general machineries.

EXAMPLES

[0045] The present invention will now be described more specifically by examples, but the present invention is not limited by the following examples so long as the subject does not depart the spirit of the invention.

[0046]

The methods for measuring the properties of the components used in the following sections are as follows.

This is measured by using a laser diffraction/scattering particle size analyzer according to JIS Z8825- 1 (2001 ). In the examples, measurement data from individual suppliers were used.

With reference to JIS Rl 670:2006, this was calculated by using SEM images. <Glass transition temperature (Tg) of component B>

According to JIS K7121:1987, this was obtained by measuring with a differential scanning calorimetry tool (DSC).

With reference to ASTM D5279, RDS II from Rheometrics, Inc., the dynamical viscoelasticity measurement tool, was used for the measurement in which torsion was periodically applied at a frequency of 1 Hz to a sample of 10 mm in width, 1.4 mm in thickness and 55 mm in length within the temperature range from -60°C to 100°C.

[0047]

< Examples 1 to 4, and Comparative Example 1 : component A/B ratio 90/10>

The component A: polystyrene (BASF, molecular weight (Mw): 274,000 g/mol), and the component B: styrene /isoprene block copolymer (Kuraray Co., Ltd., Tg=8°C) were blended in 90:10 based on volume ratio, the component C: Ti/Ba glass sphere-like filler (Union Co., Ltd., average particle diameter = 42μπι, aspect ratio 1) was added in 18% by volume, 33% by volume, 39% by volume, 44% by volume of the total amount of the composite material, which was then mixed well by a mixer, and kneaded in a twin screw kneader set at 220°C, cooled to room temperature to yield a pellet of composite material (Examples 1 to 4). The resulting pellet was shaped into a plate of 1.4 mm in thickness by hot press at 180°C. This plate was cut into an arbitrary size, and used as a sample piece for the physical property

measurement. The composite material without the component C was prepared as Comparative Example 1.

[0048]

The composite materials of Examples 1 to 4 and Comparative Example 1 are also summarized in Table 1. The behavior of the values of the loss factor (tan δ) is also depicted in the Figure 1.

As can be seen from the Figure 1, in the Comparative Example 1 with a matrix alone in which the component A/B ratio is 90/10, tan δ has only a peak near 10°C, but in the Examples 1 to 4 in which fillers were added, the peak temperatures shifted to higher temperatures, and surprisingly, the peak values of tan δ significantly rose in proportion to the content ratios by volume of the fillers.

[0049] Table 1: Component A/B ratio 90/10

[0050]

The above described component A and component B were fixed in a ratio of 97:3 based on volume, and the above described component C was added in 29% by volume and 45% by volume of the total amount of the composite material, which was then mixed well by a mixer, and kneaded in a twin screw kneader set at 220°C, cooled to room temperature to the composite material (Examples 5 to 6). The resulting pellet was shaped into a plate of 1.4 mm in thickness by hot press at 180°C. This plate was cut into an arbitrary size, and used as a sample piece for the physical property measurement. The composite material without the component C was prepared as Comparative Example 2.

[0051]

The composite materials of Examples 5 to 6 and Comparative Example 2 are also summarized in Table 2 similar to the Table 1.

In the Examples 5 to 6 in which filler were added, the peak temperatures shifted to high temperature portions, and surprisingly, the peak values of tan δ significantly rose in proportion to the content ratios by volume of the fillers. [0052]

Table 2: Component A/B ratio 97/3

[0053]

A composite material was obtained which contains the above described component A and component B: polyurethane (DIC Corporation, Tg = 49°C), and the above described component C in the volume ratio described in Table 3. In Example 7 to 16, the water-dispersed component B was well mixed into the component C fluidized in a spray-coater, and the mixture was then dried, and well remixed with the component A in a mixer. A composite material was also obtained which contains, in the volume ratio described in the Table 4, the component A: polypropylene (BP PLC, Tg = -10°C), and the. component B and the component C which were used in the Example 7 (Example 17). Then, it was kneaded in a twin screw kneader set at 220°C, cooled to room temperature to yield a composite material (Examples 7 to 17). The resulting pellet was shaped into a plate of 1.4 mm in thickness by hot press at 180°C. This plate was cut into an arbitrary size, and used as a sample piece for the physical property measurement.

[0054]

The composite materials of the Examples 7 to 17 are also summarized in the Table 3 similar to the Table 1. As references of stiffness change, storage shear moduli G' at peak temperature, the rates of change of storage shear modulus G' at peak temperature from the component A alone are also summarized in the Table 3.

In the Examples 7 to 17 in which fillers were added, the peak temperatures shifted to higher temperatures, and surprisingly, the peak values of tan δ significantly rose.

[0055]

Table 3

[0056]

A composite material which contains, in the volume ratio described in Table 4, the component A which is used in the Comparative Example 1, and the component B: styrene-isoprene block copolymer (Kuraray Co., Ltd, Tg = 8°C), and component C: calcium carbonate (Toyo Fine Chemical Co., Ltd, average particle diameter =

20μιη, aspect ratio = 4.1) was obtained (Example 18). The production method is same as that in the Example 1.

A composite material which contain milled glass fiber (Asahi Fiber Glass Co., Ltd., average fiber diameter = ΙΟμπι, aspect ratio = 20) as the component C in the volume ratio described in the Table 4 were also obtained (Examples 19).

A composite material which contains, in the volume ratio described in the Table 4, the component A and the component C which were used in the Example 7, and polyurethane (DIC Corporation, Tg = 7°C) instead of the component B, was obtained (Example 20). The composite material in examples 19 and 20 were obtained by a similar method as that of the Example 7.

The resulting pellet was shaped into a plate of 1.4 mm in thickness by hot press at 180°C, which plate was cut into an arbitrary size, and used as a sample piece for the physical property measurement.

[0057]

The composite materials of the Examples 18 to 20 are also summarized in the Table 4 similar to the Table 1.

In the Examples 18 to 20 in which fillers were added, the peak temperatures shifted to high temperature portions, and surprisingly, the peak values of tan δ significantly rose.

[0058] Table 4

[0059]

A material of 100% by volume of the component A used in the Example 1 (Comparative Example 3), a composite material containing the component A and the component B which were used in the Example 1 in the volume ratio of 70:30 (Comparative Example 4), a material of 100% by volume of component B used in the Example 1 (Comparative Example 5), a material of 100% by volume of the component A used in the Example 17(Comparative Example 6) are also summarized in Table 5 similar to the Table 1.

[0060]

Table 5

INDUSTRIAL APPLICABILITY

[0061]

The composite material according to the present invention can be used for various use applications requiring materials having effects of lowering vibration, lowering noise and cutting noise, as building material including wall material, floor material, ceiling material having vibration control sound control sound insulating effects, as a material for enhancing quietness by lowering noise and for preventing degradation of component by lowering vibration, used for professional-use and home-use equipment such as partitions for dividing room, refrigerators, washing machines, driers, cleaners, air-conditioning equipment, etc., as material for enhancing quietness for use in vehicles such as cars, and as vibration isolating materials used for mattings of vibrating electronic equipment, office machines, and general machineries, and also in audio equipment for reproducing clear sound by lowering the vibration of the housing and relevant components thereof.

Claims

1. A composite material comprising at least three components of a component A, a component B, and a component C,

the component A being a thermoplastic resin,

the component C being a filler with an aspect ratio of less than 50,

2. A composite material comprising at least three components of a component A, a component B, and a component C,

the component A being a thermoplastic resin,

the component C being a filler with an aspect ratio of less than 50,

wherein a volume ratio of the component A and the component B in the composite material fulfills A > B, the component B is contained in the composite material in an amount of less than 10% by volume and does not form a continuous phase,

there are two peaks of an enhanced loss factor (tan δ) such that a peak temperature at higher temperature is larger by not less than 15°C than a peak temperature at lower temperature.

3. The composite material according to claim 1 or 2, wherein the component A is an amorphous resin.

4. The composite material according to any one of claims 1 to 3, wherein the component C is a filler with an aspect ratio of less than 5.

5. The composite material according to any one of claims 2 to 4, wherein a change rate of storage shear modulus (G') taken at the higher peak temperature of the loss factor (tan δ) originated from the component B of the composite material is not less than 90% from that of the component A alone taken at the same temperature.

6. The composite material according to any one of claims 1 to 5, wherein the component B is submicron-dispersed into the component A in the composite material.

7. The composite material according to any one of claims 1 to 6, wherein at least a portion of the component C is coated with component B.

8. A method for improving damping property of a composite material including a component A, a component B and a component C, the method comprising the step of