JPS58104949A - Resin composition for molding structural material for acoustic appliance - Google Patents

Abstract

PURPOSE:To prepare the titled composition giving a cured product having excellent acoustic effect such as high internal loss, etc., and suitable especially to speaker box, etc., by compounding a thermosetting resin with aromatic polyamide fibers, inorganic filler, and curing agent. CONSTITUTION:The titled composition (100pts.wt.) is prepared by compounding and kneading (A) 17-40pts.wt. of a thermosetting resin (preferably a polyester resin, etc.), (B) a sufficient amount (50-80pts.wt.) of an inorganic filler having an average particle diameter of 0.2-100mu (e.g. calcium carbonate) to give a specific gravity of the cured resin composition of >=1.8, (C) 3-15pts.wt. of aromatic polyamide fibers (filaments of 2-20mm. length) as fibrous reinforcing material, and (D) a curing agent (e.g. peroxide).

Description

DETAILED DESCRIPTION OF THE INVENTION Misfires ψj occur in birch construction materials, especially resin compositions for molding materials for speaker boxes and record cabinets.

Wooden boards, plywood, aluminum die-casting, etc. have traditionally been used as structural materials for audio equipment, but wood boards and plywood are lightweight and easily vibrate, while aluminum die-casting has low vibration but has low internal loss and damping effect. inferior to

In recent years, so-called composite materials, which are plastics filled with inorganic fillers, have been used to overcome the above-mentioned drawbacks of structural materials for audio equipment.

However, although this laminated material has a well-balanced acoustic effect, it is inferior to wood boards and plywood in terms of internal loss. The appearance of the material is eagerly awaited.

The present inventors have conducted various studies on improving composite materials from this point of view, and found that a structural material molding resin for acoustic equipment containing a thermosetting resin, a curing agent, an inorganic filler, and a fibrous reinforcing material. It has been found that a molded article obtained by curing and molding a resin composition using a specific fibrous reinforcing material, that is, an aromatic polyamide fiber, has the properties listed below. .

(V internal loss is large.

T2 survival is a dog.

Q) It has a large specific gravity and does not easily cause vibration.

The present invention was completed based on the above-mentioned new findings, and an object of the present invention is to provide a resin composition that can be molded into an acoustic equipment structural material with excellent acoustic effects.

That is, the present invention provides a resin composition containing a thermosetting resin, a curing agent, an inorganic filler, and a fibrous reinforcing material, and the use of aromatic polyamide fibers as a paper reinforcing material to form a structural material for audio equipment. The present invention relates to a curing resin composition.

The thermosetting resin used in the present invention may be any resin as long as it can be used for molding structural materials for audio equipment. For example, polyester resin, epoxy resin, and phenolic resin are preferred. Ru.

The blending amount of the thermosetting resin is generally 17 to 10% based on the total composition.
40 weight.

The non-@'r-4 filler is used to lower the specific gravity and increase the rigidity of the structural material for audio equipment, and any known filler is used. Preferred examples of the filler include acid return A silica, barium sulfate, silica, etc.

The average particle size of commonly used inorganic 11 fillers is 02 to io
It is about oμ.

The inorganic fillers may be used alone or in combination.

Further, the inorganic filler can be used after its surface is treated with a silane coupling agent or the like.

The amount of inorganic filler added is sufficient to make the specific gravity of the cured product of the resin composition of the present invention 1.8 or more, and the amount of inorganic filler added to achieve this amount is It varies depending on the type of ridge, but usually □.

It is approximately 50 to 80% by weight based on the entire resin composition.

1’　”　’II:’, l.

In the present invention, the amount of inorganic filler to be added to the composition can be increased by appropriately setting the particle size distribution of the inorganic filler by surface treating the inorganic filler as described above. Details are disclosed in Japanese Patent Publication No. 44-5094.

As the aromatic polyamide fibrous reinforcing material used in the present invention, it is preferable to use filaments with a length of about 2 to 20 W, such as chopped strands. Examples include those obtained by reacting benzene dicarboxylic acids such as terephthalic acid) and aromatic diamines 1 (for example, phemolenediamines such as tj:, p-diaminobenzene), and specifically Kepler. 49
Aramid (trademark) (manufactured by DuPont, USA) is exemplified as a preferred example.

In the present invention, it is preferable to use only a fibrous reinforcing material that is mapped to the aromatic polyamide, but within 50 parts by volume of the total fibrous reinforcing material added (10
Fibers other than aromatic polyamides (for example, glass fibers, vinylon fibers, acrylic fibers, etc.) can be used in combination.

The amount of aromatic polyamide fiber added is 3.0% based on the total composition.
When the additive amount is preferably 3i, t or more, the internal loss of the structural material for sound 111 equipment obtained by completely curing and molding the resin composition of the present invention will be greater. 1
However, in consideration of the moldability of the resin composition of the present invention, the upper limit of the amount of polyamide fiber added (preferably about 15% by weight is 0') and the curing agent used in the present invention should be In the structural material for audio equipment obtained by curing and molding the resin composition of the present invention, It is preferable that the total specific gravity of the resin composition is 1.8 or more.2 If desired, the resin composition of the present invention may contain known additives such as curing accelerators, pigments, and silane coupling agents. May be added.

Therefore, the above-mentioned 1. Total composition standard' and 1. These additions,
It also includes agents.

The resin composition of the present invention is usually prepared as a premix.

To fully mold the structural material for #@' equipment using this resin composition, compression molding is usually employed, but transfer molding or injection molding may be employed in some cases.

The present invention is constructed as described above, and the structural material L1 for acoustic equipment obtained by curing and molding the resin composition of the present invention has high rigidity and can absorb vibration 111' (that is, internal (loss is large) and mechanical strength such as impact resistance is large.

In the examples, 1 part' means parts by weight.

Dicumyl peroxide 0.5 part 0.5
Zinc stearate 1 part 1.0 Calcium carbonate 40 parts 38.3 Barium carbonate
40 parts 38.3-1, ■ Kepler 49 Af(t) 8 parts 7.7(
Average length: 3.2 m) The above compositions were mixed at room temperature in a kneader (7 resin compositions were prepared).

Dicumyl peroxide 0.5 parts 05 Zinc stearate 1.0 parts 1.0 Calcium carbonate 70.0 parts 71.1 Kevlar 49 Aramid■ 10.0 parts 1O12 (average length 3.2
m) The above composition 1 was mixed at room temperature in a kneader to form a resin composition. and unsaturated g used in 2
Rixxf+Tsuki・::、fat 1ripo! J, a) PB-
101o(-・,.

Comparative Example 1 Comparative Example 1 Example 1 except that the aromatic polyamide fiber was not used in Example 1. A resin composition was obtained in the same manner.

Comparative Example 2 In Example 2, the same amount of glass fiber (average length 3.21111) was used in place of the aromatic polyamide fiber. A p-resin composition was prepared in the same manner as in Example 2 except for the use.

Experimental example 1 Implementation? "Jl, using the resin compositions obtained in Example 2, Comparative Example 1 and Comparative Example 2, at 130°C, 39 Ky
/ d, Obtained by heating and press-molding an 8t speaker box under conditions of 5 minutes. A board cut from the speaker box thus obtained (vertical, 15mm, width, 4c111z thickness, 2cvn) .

Table 1 shows the results of characteristic tests using n
In Table 1, the resonance sharpness was measured by holding one end of the plate and using the vibration characteristic measurement method.

(Margin below) Table 1 〉

Claims (3)

[Claims] (1) Structural material molding for audio equipment characterized by using aromatic polyamide fibers as the fibrous reinforcing material in a Kurayoshi resin composition of thermosmoking resin, curing agent, inorganic filler, and fibrous reinforcing material. Resin composition for use. (2) The resin composition according to claim (1), wherein the amount of aromatic polyamide fiber blended is 3 weight or more based on the total composition. (3) The resin composition according to claim (1), wherein the cured product of the resin composition has a specific gravity of 1.8 or more.