JP2558337B2 - Acoustic housing composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel acoustic housing composition. More specifically, the present invention relates to an acoustic housing composition having high specific gravity, excellent acoustic characteristics, high strength, good scratch resistance and color development properties, and suitable for colored colored acoustic products. It is a thing.

[Prior Art] For housing materials of acoustic products such as speaker boxes, boomboxes, players, cassette halves,
Excellent acoustic properties, excellent mechanical properties such as tensile strength and impact resistance, less likely to be damaged when dropped or transported, excellent in scratch resistance, and surface damage due to collision between housings and friction It is required to have properties such as that whitening and whitening hardly occur, and that color products have excellent coloring and gloss.

Conventionally, as a housing material of the acoustic product, impact-resistant polystyrene containing an inorganic filler is often used because it is inexpensive and has relatively good moldability, mechanical properties, and acoustic properties. There is. However, although this material has relatively good mechanical properties and acoustic properties, it has a problem that scratch resistance, color development, glossiness, etc. are not necessarily sufficient.

As described above, as a housing material for an acoustic product, a material that can sufficiently satisfy all of price, moldability, acoustic property, mechanical property, scratch resistance, color developability and glossiness has not been found yet. Is the current situation.

[Problems to be Solved by the Invention] Under these circumstances, the present invention is inexpensive and has a balance of characteristics such as moldability, acoustic characteristics, mechanical characteristics, scratch resistance, color development and gloss. The purpose of the present invention is to provide an excellent acoustic housing composition.

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies to develop an acoustic housing composition that is inexpensive and has an excellent balance of the above properties, and as a result, general-purpose polystyrene (GP-PS) has been obtained. ) And impact-resistant polystyrene (HI-PS) in specific proportions, mixed with zinc oxide, rubber-like elastic body, silicone oil, specific dispersant and colorant in predetermined proportions. It was found that the above-mentioned components can meet the purpose, and the present invention has been completed based on this finding.

That is, the present invention relates to (A) general-purpose polystyrene (GP
-PS) and impact-resistant polystyrene (HI-PS) in a weight ratio of 5
35 to 60% by weight of mixed polystyrene resin contained in the ratio of 0:50 to 80:20, (B) 40 to 65% by weight of zinc oxide powder having an average particle size of 3 μm or less, and (C) 2 to 6% of rubber-like polymer. %
(D) 1 to 3 parts by weight of silicone oil, (E) at least one dispersant selected from higher calcium, its calcium salt and magnesium salt to 0.1 to 100 parts by weight of a resin composition containing 0.7 parts by weight and (F) colorant 0.5
The present invention provides an acoustic housing composition containing about 10 parts by weight.

 Hereinafter, the present invention will be described in detail.

In the composition of the present invention, GP-PS and HI-PS are used as the matrix resin of the component (A) in a weight ratio of 50:50 to 80:50.
A mixed polystyrene resin containing 20 parts is used. If the content of GP-PS in the mixed polystyrene resin is less than 50% by weight, the tensile strength of the composition is not sufficient, and 80% by weight
If it exceeds, impact resistance tends to decrease.

The GP-PS is obtained by polymerizing a styrene monomer, has excellent moldability, good dimensional accuracy, and good water resistance and rigidity, but has the drawback of being poor in impact resistance. . On the other hand, HI-PS is improved by adding synthetic rubber or rubber latex during the polymerization of styrene monomer so that the impact strength is 5 to 10 times that of GP-PS. It has the disadvantage of poor rigidity. In the present invention, by mixing GP-PS and HI-PS having such characteristics in the above proportions, a mixed polystyrene resin that covers the drawbacks of each polystyrene resin is used as a matrix resin.

In the composition of the present invention, zinc oxide powder having an average particle diameter of 3 μm or less is used as the component (B). This zinc oxide powder has the function of making the composition dense and having excellent acoustic characteristics. When the average particle size of the zinc oxide powder exceeds 3 μm, impact resistance tends to decrease. In the composition of the present invention, a rubbery polymer is used as the component (C). The type of the rubber-like polymer is not particularly limited, and examples thereof include natural rubber, butadiene polymer (BR), butadiene-styrene copolymer (SB
R), butadiene-acrylonitrile copolymer (NBR),
Styrene-butadiene-acrylonitrile copolymer, butadiene-based synthetic rubber such as chloroprene polymer (CR), isoprene polymer rubber (synthetic natural rubber), isobutylene-isoprene copolymer rubber (butyl rubber, IIR) acrylonitrile-isoprene copolymer Rubber, isobutylene polymer rubber, ethylene-propylene copolymer rubber, ethylene-vinyl acetate copolymer rubber, chlorinated polyethylene, chlorosulfonated polyethylene, urethane rubber, silicone rubber, fluororubber, acrylic rubber, epichlorohydrin rubber, propylene oxide Rubber or the like is used. These rubber-like elastic bodies may be used alone or in combination of two or more. This rubber-like elastic material is used to further improve the impact resistance of the composition.

In the composition of the present invention, the above-mentioned component (A), (B)
The content ratio of the component and the component (C) is 35 to 60% by weight, preferably 40 to 55% by weight, and 40 to 65% by weight, preferably 40 to 65% by weight, for the total amount thereof. 45 to 60% by weight, the component (C) is selected in the range of 2 to 6% by weight, preferably 3 to 5% by weight. The content of the component (A) is 35% by weight
If it is less than 60% by weight, the color developability is not sufficient, and if it exceeds 60% by weight, the density tends to be small and the acoustic characteristics tend to be deteriorated.
If the content of the component (B) is less than 40% by weight, the density is low and the acoustic properties may be inferior. If it exceeds 65% by weight, the tensile strength tends to be low and the color development tends to be poor. . If the content of the component (C) is less than 2% by weight, the impact resistance is not sufficient, and if it exceeds 6% by weight, the scratch resistance and the color development tend to be deteriorated.

In the composition of the present invention, silicone oil is the total amount of the components (A), (B) and (C) as the component (D).
It is blended in a ratio of 1 to 3 parts by weight with respect to 100 parts by weight.
This silicone oil has the function of improving the compatibility between the zinc oxide powder and the matrix resin and improving the scratch resistance of the composition. If this amount is less than 1 part by weight, the scratch resistance is not sufficient, and if it exceeds 3 parts by weight, the color developability tends to decrease.

The type of silicone oil used as the component (D) is not particularly limited, and examples thereof include dimethyl silicone oil, phenylmethyl silicone oil, methyl hydrogen silicone oil, amino-modified silicone oil, fluoropropyl group-substituted silicone oil, and the like. These may be used alone or in combination of two or more.

Further, in the composition of the present invention, the dispersant as the component (E) is the total amount of the components (A), (B) and (C) 10
It is used in a proportion of 0.1 to 0.7 parts by weight with respect to 0 parts by weight.
This dispersant has the effect of improving the dispersibility of the zinc oxide powder in the matrix resin and making the tensile strength and color development sufficient, and if the content is less than 0.1 parts by weight, color development is poor. Moreover, the tensile strength is not sufficient, and if it exceeds 0.7 parts by weight, mechanical properties such as tensile strength and impact strength tend to be deteriorated.

In the present invention, the dispersant is a higher fatty acid,
Calcium salts and magnesium salts thereof, for example, higher fatty acids such as palmitic acid, stearic acid and behenic acid and their calcium salts and magnesium salts are used. These dispersants may be used alone or in combination of two or more.

Furthermore, in the composition of the present invention, the colorant as the component (F) is the total amount of the components (A), (B) and (C).
0.5 to 10 parts by weight, preferably 1.0 to 5 per 100 parts by weight
Used in proportions by weight. If this amount is less than 0.5 part by weight, the scratch resistance and color developability may be poor, and if it exceeds 10 parts by weight, there is no adverse effect, but the effect is not improved relative to the amount. The colorant is not particularly limited, and any one of inorganic pigments and organic pigments conventionally used for coloring plastics can be selected and used. Examples of the inorganic pigments include white oxides such as titanium oxide, zinc white, lead white, lithopone-precipitating barium sulfate and calcium carbonate, black pigments such as carbon black and lamp black, zinc dust, lead suboxide, and slate powder. Gray pigments, cadmium red, cadmium mercury red, silver vermilion, red iron oxide, red pigments such as molybdenum red, red lead, amber, iron oxide-based brown pigments, cadmium yellow, barium yellow, strontium yellow, zinc yellow, loess, titanium Yellow pigments such as yellow, green pigments such as pyridian, chrome oxide green, cobalt green, cobalt chrome green, chrome green, blue pigments such as ultramarine blue, navy blue, cobalt blue, cerulean blue, and purple pigments such as manganese purple and mars purple. Furthermore, metal powder pigments and the like can be mentioned.

On the other hand, examples of the organic pigments include azo pigments, nitroso pigments, nitro pigments, basic dye lakes, acidic dye lakes, mordant dye lakes, and hithalocyanine pigments. These colorants may be used alone,
You may use it in combination of 2 or more type.

The density of the composition of the present invention is 1.5 g / cm ³ or more, preferably 1.
It is desirable to be 7 g / cm ³ or more. This density is 1.5 g / cm ³
If it is less than the above range, the acoustic characteristics may be deteriorated, which is not preferable.

In the composition of the present invention, as long as the object of the present invention is not impaired, other thermoplastic resins, other metal-based fillers, inorganic fillers, fillers such as organic fillers, and coupling agents, as desired. , Modified polyolefins, and various additives usually used in resin compositions, such as lubricants, stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants,
A plasticizer or the like can be added.

The acoustic housing composition of the present invention comprises a required amount of each of the components (A), (B), (C), (D), (E), and (F), and various fillers used as desired. And additives can be prepared by melt-kneading and compounding in a conventional manner. Melt kneading can be performed by, for example, a method using a Henschel mixer, a single-screw or twin-screw extruder, a Banbury mixer, a roll or the like, and other conventional methods, but particularly, using a Henschel mixer, an extruder, a Banbury mixer. Is preferred.

The thus prepared acoustic housing composition of the present invention is used for colored acoustic products having excellent acoustic properties and mechanical properties, and good scratch resistance and color development, for example, by an injection molding method or the like. The housing can be obtained.

[Examples] Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

 The following physical properties of the molded product were obtained.

(1) Density (g / cm ³ ) (2) Tensile strength (kg / cm ² ) Determined according to ASTM D-638.

(3) Izod impact strength (kg · cm / cm) Determined according to ASTM D-156 (with notch).

(4) Internal loss (tan δ) Frequency of 30 with a vibron measuring machine (manufactured by Toyo Bold Co., Ltd.)
Tan δ was measured under the conditions of 0 Hz and temperature of 25 ° C. The larger tan δ, the better the acoustic characteristics, and the preferable tan δ is a value larger than 0.04.

(5) Scratch resistance 1 x 100 x 100 x 3.2 mm with wrinkled plates on top of each other
After rubbing 50 times under load, the appearance was visually evaluated.

◯: No abnormality Δ: Slightly whitened X: Scratched and whitened overall The shape of the grain is shown in FIG.

(6) Color development The wrinkled plate of (5) was visually evaluated.

◯: Dark color Δ: Slightly white color x: Overall white In addition, the following components were used.

・ HI-PS: Idemitsu Petrochemical Co., Ltd., HT-51 ・ GP-PS: Idemitsu Petrochemical Co., Ltd., HH-30 ・ Zinc Oxide: Shodo Kagaku Co., Ltd., Zinc Hua No. 1 ・ Rubber Polymer: Shell Chemistry SBS, MI = 50g / 10min (200 ℃, 5kg) ・ Silicon oil: Shin-Etsu Silicon Co., viscosity 100cSt ・ Dispersant a: Calcium stearate b: Stearic acid d: Zinc stearate e: Sodium stearate ・Pigment f: Carbon black (black) g: Titanium oxide (white) h: Red iron oxide (vermilion) i: Cobalt blue (blue) Examples 1 to 24, Comparative Examples 1 to 16 At
After mixing at 20 to 100 ℃ for 15 to 20 minutes, use a twin-screw extruder (Nakatani Machinery Co., Ltd., 50mmφ), temperature 200 to 230 ℃, 100k
Pelletized under the condition of g / hr.

Next, a test piece was prepared from the pellet with an injection molding machine (FS-160) manufactured by NISSEI PLASTIC INDUSTRIAL CO., LTD., And each physical property was determined.
The results are shown in Table 1.

[Advantages of the Invention] The acoustic housing composition of the present invention has high specific gravity and excellent acoustic characteristics, has good mechanical characteristics such as tensile strength and impact strength, and has little damage when dropped or during transportation. Since it has excellent scratch resistance, it is extremely unlikely that the surface will be scratched or whitened due to collision or friction between the housings, and in addition, it has excellent color development and glossiness, and is also inexpensive. It is suitable for housing colored products such as speaker boxes, boomboxes, players, and cassette halves.

[Brief description of drawings]

FIG. 1 is a diagram showing the shape of a wrinkle provided on a test piece in order to evaluate the scratch resistance of the composition in Examples and Comparative Examples.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H04R 1/02 101 H04R 1/02 101A 7/02 7/02 D // (C08L 25/00 51 : 04 21:00 83:04) (72) Inventor Hideo Okawa 1 277 Izumicho, Kanda, Chiyoda-ku, Tokyo Within Calpe Industry Co., Ltd. (56) References JP-A-55-69638 (JP, A) JP-A-SHO 62-91550 (JP, A)

Claims (2)

(57) [Claims] 1. A mixed polystyrene resin, which comprises (A) general-purpose polystyrene and impact-resistant polystyrene in a weight ratio of 50:50 to 80:20, and (B) an average particle diameter of 3 μm or less. 1 to 3 parts by weight of (D) silicone oil and (E) higher fatty acid to 100 parts by weight of a resin composition containing 40 to 65% by weight of zinc oxide powder and 2 to 6% by weight of (C) a rubber-like polymer. An acoustic housing composition comprising 0.1 to 0.7 parts by weight of at least one dispersant selected from calcium salts and magnesium salts thereof and 0.5 to 10 parts by weight of (F) a colorant. 2. The composition according to claim 1, which has a density of 1.5 g / cm ³ or more.