Yamaha Corporation

Nippon Steel Chemical Co., Ltd.

Yamaha Fine Technologies Co., Ltd.

Yasutaka Nakamura

Hideo Suzuki

Kunio Hiyama

Rento Tanase

Atsushi Yoshida

Masao Imanishi

Masaru Matsushita

Takayuki Endo

Masuhiro Okada

Kenji Ito

Emiko Suzuki, Legal Representative

Akira Kaneko

Yutaka Hamada

Toshiyuki Suzuki

Kazuhiro Muneta

Katsutoshi Oda

It is an object of the present invention to provide a resin composition for FRP, an FRP sheet and a molded product that enable inhibition of the whitening in and between fiber bundles. A resin composition for FRP according to an embodiment of the present invention is a resin composition with which a fibrous reinforcement sheet is to be impregnated for formation of FRP, and contains methyl methacrylate as a principal component, a methyl methacrylate polymer, a polymerization initiator, and at least one of dendrimer (meth)acrylate and glycidyl (meth)acrylate, as a monomer. An FRP sheet according to another embodiment of the present invention includes a matrix and a fibrous reinforcement sheet in the matrix. The matrix contains the hardened resin composition for FRP.

Resin composition for FRP, FRP sheet and molded product

A sound absorbing structure is constituted of a vibration plate and a rear air layer and is installed in a luggage compartment or trunk which is separated from a cabin in a vehicle. Sound waves entering into the luggage compartment drive the vibration plate to vibrate so that acoustic energy is converted into mechanical energy and is consumed by way of vibration of the vibration plate. By appropriately setting parameters and dimensions, the sound absorbing structure efficiently absorbs low-frequency sound such as road noise occurring due to friction of wheels of the vehicle traveling on a road.

Sound absorbing structure built into luggage compartment of vehicle

A sound absorbing structure is constituted of a housing having a hollow portion and an opening and a vibration member composed of a board or diaphragm. The vibration member is a square-shaped material having elasticity composed of a synthetic resin and is bonded to the opening of the housing, thus forming an air layer closed inside the sound absorbing structure by the housing and the vibration member. In the sound absorbing structure, when the lateral/longitudinal dimensions of the air layer and characteristics of the vibration member (e.g. a Young's modulus, thickness, and Poisson's ratio) are set such that the fundamental frequency of a vibration occurring in a bending system falls within 5% and 65% of the resonance frequency of a spring-mass system, a vibration mode having a large amplitude occurs in a frequency band lower than the resonance frequency of the spring-mass system, this improving the sound absorption coefficient.

Sound absorbing structure and vehicle component having sound absorbing property

A diaphragm for use in a speaker is manufactured using a plurality of thin wooden boards having flat rectangular shapes. The thin wooden boards are impregnated with a resin; then, a plurality of cutouts, which are elongated along wooden fiber directions or which are elongated in directions crossing wooden fiber directions, are formed in the thin wooden boards. Instead of the cutouts, it is possible to form a plurality of folded portions elongated in directions crossing wooden fiber directions. The thin wooden boards are integrally laminated together in such a way that the wooden fiber directions thereof mutually cross with a prescribed angle therebetween. The thin wooden boards integrally laminated together are subjected to thermal pressing so as to form a wooden vibrator serving as the diaphragm. Thus, it is possible to easily produce the diaphragm having a high strength and superior acoustic characteristics without causing defects.

Diaphragm for speaker and manufacturing method therefor

In order to provide a sound-absorbing panel and a production method of the same which has excellent freedom of design and have small differences in the maximum sound-absorbing coefficients among products, a sound-absorbing panel is adopted which is characterized by a panel main body which is constituted by arranging both a porous veneer of 0.02-0.5 mm thickness with multiple pierced apertures of 0.1 mm or smaller aperture diameters or 0.2 mm or smaller aperture diameters and a porous sound-absorbing base material set at a backside of the porous veneer so as to be overlapped, and is characterized by having a value of airflow resistance in a range of 0.1-1.0 Pa.

Sound-absorbing panel and production method of the same

In order to provide a sound-absorbing body which has both a thin thickness and improved sound-absorption characteristics with regard to a low tone range sounds, the sound-absorbing body () includes: an organic hybrid sheet () constituted from an organic low-molecular material which is spread in a matrix polymer; and a gastight air cell () which is closely provided at a backside () of the organic hybrid sheet, wherein the organic hybrid sheet indicates both a sound-absorption peak of a random incidence sound-absorption coefficient at a frequency band of 400 Hz or lower and another sound-absorption peak when the organic hybrid sheet is vibrated by applying air vibration caused by sound, because of adhering the organic hybrid sheet to the gastight air cell.

Sound absorbing body

A sound absorbing material which comprises a base layer 1 having a porosity of 5 to 50% by volume and a decorative layer 3 having a porosity of 5 to 50% by volume integrally, and which is obtained by sprinkling inorganic particles 4 containing colored particles in an amount of at least 1% by volume which are coated with a weather-resistant transparent resin so as to form a first particle layer which is to form the decorative layer 3 in the sound absorbing material, sprinkling uncolored inorganic lightweight particles 2 which are coated with a thermosetting resin on the first particle layer so as to form a second particle layer which is to form the base layer 1 in the sound absorbing material, and carrying out thermal compression integral molding of the first particle layer and the second particle layer simultaneously, is lightweight and inexpensive, and is provided with an attractive external stone-grain-like appearance, without impairing the sound absorbing ability of the material. In addition, by placing a reinforcing layer material on the top surface, bottom surface, or both surfaces of the second particle layer, and carrying out thermal compression integral molding of the first particle layer, the second particle layer, and the reinforcing layer material(s) simultaneously, it is possible to provide a sound absorbing material which is provided with rigidity to enable the material to be free-standing, without impairing the above advantages and the sound absorbing ability of the material.

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Hamamatsu, Japan

Yasutaka Nakamura