Stock material or miscellaneous articles – Sheet including cover or casing
Reexamination Certificate
2001-08-08
2003-10-21
Nolan, Sandra M. (Department: 1772)
Stock material or miscellaneous articles
Sheet including cover or casing
C428S296700, C428S308400
Reexamination Certificate
active
06635327
ABSTRACT:
TECHNICAL FIELD
The present invention generally relates to energy conversion compositions, excluding conversion of electrical energy into mechanical energy, which can effectively absorb and damp energy such as dynamic, thermal, and/or electrical energy excluding optical energy.
BACKGROUND ART
There conventionally exists a vibration energy damping material of a soft vinyl chloride resin and a plasticizer.
Such a soft vinyl chloride resin can damp vibration energy on the surface of and/or within the resin by converting the vibration energy into frictional heat, only to a very limited extent.
Japanese Laid-Open Patent Publication No. 5-332047 discloses a liquid material which absorbs or damps vibration energy to a degree. This liquid material or a viscous fluid comprises a glycol as a chief ingredient. Vibration energy or seismic energy generates an electric field in the viscous fluid and changes the viscosity of the fluid, an attempt to efficiently damp the dynamic energy.
A very large amount of liquid material is required to effectively damp huge seismic energy, for instance, from a major earthquake. Due to gradual oxidization of the liquid material, its damping performance gets lowered over time, requiring periodical refreshment of the liquid material. Accordingly, there exists a strong demand for a vibration damping material which with a minimum amount can efficiently damp seismic energy or vibrations over a longer period of time without such refreshment.
A sound or noise absorptive or damping material containing glass wool is known. Glass wool can damp sound or noise by consuming the energy as frictional heat when sound collides with the surface of glass wool fibers and passes therethrough.
The glass wool type sound absorptive material, however, need be prepared relatively thick to provide sufficient sound absorption. The material cannot effectively absorb sound of a low frequency below 1,000 Hz. The material does not function well at a frequency below 500 Hz.
There is an impact absorptive or damping material. Japanese Patent Laid-Open Publication No. 6-300071 discloses an impact absorptive material which comprises short fibers dispersed in a foamed polymer. This impact absorptive material can damp an impact applied against a surface portion of the formed material through the gradual collapse of the structural integration of the formed material. The short fibers dispersed in the foamed material act as a physical binder to promote the tensile strength of the material and prevent its cracking.
This impact absorptive material, however, requires a considerable thickness and volume to provide sufficient impact damping. Accordingly, if there is no sufficient room for installment, this impact absorptive material cannot be conveniently utilized.
There is an electromagnetic shield material as proposed in Japanese Patent Laid-Open Publication No. 5-255521, which can absorb electromagnetic energy to an extent. This material comprises an ultraviolet absorptive compound capable of absorbing or damping ultraviolet rays of a wavelength of 250 to 400 nm through excitation of the molecules of the compound and conversion of the ray energy into thermal energy.
This material need be 10 to 20 mm thick to provide a sufficient absorption of ultraviolet rays. Such a thick sheet hinders visibility. A demand for a material which can provide a thin but effective electromagnetic shield is strong.
Butyl rubber or NBR is conventionally utilized to provide a vibration damping material. Such a rubber material is economical and easy to process as well as possesses a considerable mechanical strength.
Such a rubber material shows an excelled vibration damping property among polymers, however, if a rubber material is used singly, its damping ability is somehow limited. Therefore, a metal plate or core or oil damper is conventionally incorporated in a rubber-type vibration damping material, which is rather complicated and costly to manufacture.
Accordingly, there is a strong demand for a vibration damping material which itself can provide excellent vibration absorption or damping.
Japanese Patent Laid-Open Publication No. 5-5215 discloses an endothermic fiber material. This material is a polymer comprising a straight-chain aliphatic carboxylic acid and straight-chain aliphatic diol, such as polyethyleneadipate, polypentamethyleneadipate, or polytetramethynenglutarate. The polymer absorbs heat as it melts and provides heat damping, though, a large amount of polymer is required to provide sufficient heat absorption.
A viscous fluid mainly composed of a glycol provides a high latent heat medium to be used as a transmission cooler, engine coolant or mold cooler. The cooling property of the fluid is given by the following equation.
(&Dgr;
H−RT
)/
V
=(
SP
)
2
&Dgr;H: latent heat, SP: SP value (solubility parameter). The SP value is an indication of polarity and increases as dipoles increase. Water has the largest SP value, however, use of water is not practical because water tends to corrode metals. Glycol has an excellent rust inhibition property, however, glycol does not provide a high latent heat property.
As described above, conventional energy conversion (damping) materials or compositions have insufficient damping capabilities, or require a considerable thickness or volume to provide a satisfactory damping capability.
The inventors have discovered through a lengthy research on energy conversion compositions that the magnitude of dipole moment of the compositions is directly related to their energy absorption/conversion/damping capability.
The inventors have also found that the dielectric loss factor of the compositions is related with their energy absorption/conversion damping capability.
Accordingly, an object of the present invention is to provide an energy conversion composition, excluding conversion of electrical energy into mechanical energy, which has an excellently improved capability of absorbing/converting or damping energy such as dynamic, thermal, and/or electric energy excluding optical energy. Another object, of the present invention is to provide an energy conversion/damping composition which can provide an excellently improved ability with a minimal thickness or volume.
DISCLOSURE OF THE INVENTION
An energy conversion composition according to this invention can be prepared into, but not limited to, an unconstrained or constrained vibration damping sheet, paint, paper, asphalt material (for automobile flooring), or a vibration damping material for asphalt roads (noiseless roads), or sound or noise absorptive material for sound absorptive sheets, fibers, foam materials, films or molds, or impact absorptive material for training shoe soles, protections, head gears, plaster casts, mats, supporters, handle grips and saddles of bicycles or motorbikes, front forks, grip ends of tennis or badminton rackets, baseball bats, or golf clubs, grip tapes, hammer grips, slippers, gun bottoms, shoulder pads, or bulletproof jackets, or vibration-proof rubber material for earthquake damping rubbers or molds, or electromagnetic shield material for X-ray or ultraviolet shield sheets, or piezoelectric material (excluding ones that convert electrical energy to mechanical energy), or endothermic material for endothermic fibers or pellets, or viscous fluid for earthquake damping apparatus, or polarity liquid for engine mount liquids, shock absorber oils, power supply transmission cooling liquids, engine coolants, floor heater media or solar heat media.
The energy conversion composition according to this invention is characterized in that its base material contains a moment promoter or moment activator which increases or promotes the amount or magnitude of dipole moment in the base material.
Such a base material is not limited to but may be a polymer material such as polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polyvinylidene fluoride, polyisoprene, polystyrene, styrene-butadiene-acrylonitrile copolymer, styrene-acrylonitrile copolymer, acryloni
Hori Mitsuo
Ohira Yasuyuki
Cantor & Colburn LLP
Nolan Sandra M.
Shishiai-Kabushikigaisha
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