JPH0833095A - Speaker edge material - Google Patents

Abstract

PURPOSE:To develop speaker edge material of a polyurethane foam which is provided with both weather resistance and moisture resistance which are more excellent than conventional ones and is capable of providing the tone quality which is almost the same as that of a polyester system soft polyurethane foam. CONSTITUTION:The weather resistance and the moisture resistance which are more excellent than those of conventional speaker edge material of a polyurethane foam can be satisfied at the same time, by using 25 to 85 weight % of the polyether polyester polyol characterized by obtained by reacting the compound selected from the group composed of the dielectric having polyoxyethylene polyol and a hydroxyl radical with the compound having aromatic polycarboxylic acid anhydride and cyclic ether radical, as main material polyor, for all polyors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for an edge of a diaphragm for a speaker used in various audio equipments and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, as an edge material for speaker diaphragms used in these, woven cloth coated or impregnated with resin such as SBR or NBR, or polyester-based or polyether-based soft polyurethane foam is used. Many are used.

However, in the case of the woven cloth coated or impregnated with the resin such as SBR or NBR, the humidity and heat resistance are weak, and the linearity of the amplitude with respect to the input is poor, so that the minimum resonance at the time of high input is obtained. There is a drawback that the frequency (fo) is greatly reduced. Flexible polyurethane foams are superior in this respect. But,
In the case of this flexible polyurethane foam, polyester-based flexible polyurethane foam also has weak moisture resistance, while in the case of polyether-based flexible polyurethane foam, its moisture resistance is strong, but its weather resistance is weak. Therefore, there is a drawback that pinholes are easily generated. or,
Generally, the polyether flexible polyurethane foam tends to be inferior in sound quality to that of the polyester flexible polyurethane foam. It is presumed that this is because the elasticity of the material is large, so that reverse resonance is likely to occur.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies on the above problems, the present invention provides a polyurethane foam which has excellent weather resistance and moisture resistance and can provide sound quality comparable to that of a polyester-based flexible polyurethane foam. The present invention was achieved by developing a speaker edge material.

[0005]

That is, the gist of the present invention is a speaker edge material of polyurethane foam obtained by mixing a polyol, an organic diisocyanate, a foaming agent, a foam stabilizer, a catalyst, etc. used as main raw materials. Therefore, 25% by weight or more and 85% by weight or less of the polyol in the raw material is a compound selected from the group consisting of polyoxyalkylene polyol and its derivative having a hydroxyl group, which is an aromatic polycarboxylic acid anhydride and a cyclic ether. The present invention relates to a speaker edge material of polyurethane foam, which is a polyether polyester polyol (Japanese Patent Publication No. 48-10078) obtained by reacting a compound having a group.

Preferably, the polyether polyester polyol is a polyether polyester polyol obtained by ring-opening polymerization of polyoxypropylene triol with phthalic anhydride and propylene oxide.

More preferably, the foam stabilizer is an active hydrogen-containing organosilicon compound. Examples of the active hydrogen-containing group include a carboxyl group, a hydroxyl group, an amino group and a methoxy group, and among them, a carboxyl group and a hydroxyl group are preferable. As the structure of the active hydrogen-containing organosilicon compound, the following structural formula is recommended.

[0008]

Embedded image m: integer of 1 to 200 n: integer of 1 to 50 R: divalent organic group containing polyoxyethylene and polyoxypropylene

Further, it is preferable to improve the weather resistance by adding 0.4% by weight or more of carbon black to all polyols.

In the present invention, 25% by weight of the above polyether polyester polyol is used as the polyol.
It is necessary to use not less than 85% by weight, but examples of the polyol that can be used as the polyol to be used in combination include glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, ethylenediamine, diethylenetriamine, diethylene glycol, dipropylene glycol. There are polyether polyols obtained by ring-opening polymerization of such polyhydroxyl compounds with propylene oxide, ethylene oxide and the like using an alkali catalyst, and those having a viscosity of 5000 cp or less are preferable. Further, a graft polyol obtained by graft-polymerizing polystyrene or polyacrylonitrile with a polyether polyol or a polyether ester polyol can also be used.

When the content of the polyether polyester polyol is 25% by weight or less of the total polyol, it is difficult to obtain the effect described later, and when it is 85% by weight or more, the viscosity of the foaming machine becomes high and the raw materials are uniformly mixed. It will be difficult.

The polyisocyanate that can be used is an aromatic polyisocyanate containing two or more isocyanate groups in the same molecule, an aliphatic polyisocyanate or a modified product thereof. Diisocyanate, diphenylmethane diisocyanate,
Examples thereof include isophorone diisocyanate and xylene diisocyanate.

Usually, in order to make weather resistance strong and discoloration less noticeable, carbon black is added to the polyurethane foam speaker edge material at the time of foaming, but this is also effective in the present invention. When 0.4% by weight or more of carbon black is added to the polyol, good weather resistance is obtained, and discoloration due to ultraviolet rays is not noticeable.

[0014]

[Action]

(1) Obtained by reacting a compound selected from the group consisting of polyoxyalkylene polyol and its derivative having a hydroxyl group as a main raw material polyol with an aromatic polycarboxylic acid anhydride and a compound having a cyclic ether group. By using the polyether polyester polyol characterized by the above in an amount of 25 to 85% by weight based on the total weight of the polyol, it is possible to satisfy both the weather resistance and the moisture resistance, which are superior to the conventional speaker edge material of polyurethane foam.

For example, a conventional polyester type flexible polyurethane foam has relatively high weather resistance but weak moisture resistance. On the other hand, the conventional polyether-based flexible polyurethane foam has high moisture resistance but weak weather resistance. In contrast,
A polyurethane foam using the above polyether polyester polyol as a raw material can obtain weather resistance comparable to that of polyester polyurethane foam and moisture resistance comparable to that of polyether polyurethane for the following reasons. Weather resistance: Since there is a polyester portion in the raw material polyol molecule, the number of polyether bonds that are easily oxidized by ultraviolet rays is reduced, and therefore weather resistance is increased. Moisture resistance: The reason why the polyester polyurethane foam has low moisture resistance is that there are aliphatic ester bonds that are easily hydrolyzed in the raw material polyol molecules, but all ester bonds in the above polyether polyester polyol are aromatic ester bonds. Therefore, it is difficult to hydrolyze.

(2) In particular, as the above-mentioned polyether polyester polyol, a polyether polyester polyol obtained by ring-opening polymerization of polyoxypropylene triol with phthalic anhydride and propylene oxide,
Average molecular weight 2000-5000, preferably 2500
When 4000 is used, a flexible polyurethane foam having good mechanical properties can be easily foamed by using the conventional compounding formula of polyether-based flexible polyurethane foam (foaming agent, catalyst, surfactant, isocyanate, etc.). can get.

(3) Since the above polyether polyester polyol contains an aromatic ester bond in the molecule,
The viscosity is extremely high, and when foaming polyurethane foam, it is not easy to mix with other raw materials when used alone.
Therefore, it is preferably used in an amount of 85% by weight or less based on the total polyol, and the remaining 15% by weight or more is preferably mixed with another low-viscosity polyol. As a commercially available product, 3P56B (manufactured by Takeda Pharmaceutical Co., Ltd.) in which the above polyether polyester polyol and a general-purpose polyether polyol for a flexible polyurethane foam having a molecular weight of 3000 are premixed in a ratio of 3: 1 and the like are preferably used. On the other hand, when the content of the above polyether polyester polyol is 25% by weight or less based on the total raw material polyol, the features of the above polyol are not utilized in the weather resistance and moisture resistance of the product polyurethane foam.

(4) The sound quality is further improved by using an active hydrogen-containing organosilicon compound as the foam stabilizer. (5) The polyurethane foam speaker edge material manufactured in this manner has good sound quality, and particularly has the feature of extending the sound in the middle frequency range. Although the reason for this is not clear, the present inventors presume that the aromatic ester molecules in the material make it difficult for the material to undergo reverse resonance because of large energy loss inside the material.

[0019]

【Example】

[Example 1] A polyether polyester polyol having an average molecular weight of 3000 and a hydroxyl value of 56, which was obtained by ring-opening polymerization of phthalic anhydride and propylene oxide with polyoxypropylene triol having an average molecular weight of 2000 of a glycerin-propylene oxide adduct. And 100 parts by weight of a polyol in which polyoxypropylene triol of glycerin-propylene oxide (average molecular weight 3000, hydroxyl value 56) was previously mixed in a 75:25 weight ratio, and 0.3 parts of a 33% dipropylene glycol solution of triethylenediamine, Stanna octoate 0.3
Parts, 1.0 parts of general-purpose silicone surfactant for flexible polyurethane foam, 3.2 parts of water, 1.0 carbon black
And 45 parts of TDI (T-65) were rapidly mixed to obtain a polyurethane foam.

Example 2 In the above Example 1, the general-purpose silicone surfactant for flexible polyurethane foam 1.
Carboxyl group-containing silicone surfactant (Toray Dow Corning Silicone, SF291
A polyurethane foam was obtained with exactly the same formulation except that 4) was used in the same part.

Example 3 Polyoxypropylene triol having an average molecular weight of 2000 of glycerin-propylene oxide adduct was subjected to ring-opening polymerization of phthalic anhydride and propylene oxide to obtain a poly (oxyethylene) having an average molecular weight of 3000 and a hydroxyl value of 56. 100 parts by weight of a polyol in which an ether polyester polyol and polyoxypropylene triol of glycerin-propylene oxide (average molecular weight 3000, hydroxyl value 56) were mixed in advance in a ratio of 50:50 by weight, and a 33% dipropylene glycol solution of triethylenediamine in an amount of 0. 3 parts, stanas octoate 0.3 part, carboxyl group-containing silicone surfactant (SF2914) 1.0 part, water 3.2 parts, carbon black 1.0 part, and TDI (T-65) 45 parts And mix rapidly Obtaining a urethane foam.

Comparative Example 1 Polyoxypropylene triol having an average molecular weight of 2000 of glycerin-propylene oxide adduct was subjected to ring-opening polymerization of phthalic anhydride and propylene oxide to obtain a poly (average molecular weight of 3000) and a hydroxyl value of 56. 100 parts by weight of a polyol in which an ether polyester polyol and polyoxypropylene triol of glycerin-propylene oxide (average molecular weight 3000, hydroxyl value 56) were mixed in advance at a ratio of 20:80 by weight, and a 33% dipropylene glycol solution of triethylenediamine was used. 3 parts, stanna octoate 0.3 part, general purpose silicone surfactant for flexible polyurethane foam 1.0 part, water 3.2 parts, carbon black 1.0 part, and TDI (T-65) 45 parts Polyureta mixed rapidly Give a foam.

Comparative Example 2 100 parts by weight of a polyester polyol (average molecular weight 2200, hydroxyl value 60) obtained by polycondensing adipic acid-diethylene glycol-trimethylolpropane, 3 parts of a general-purpose silicone surfactant for soft polyurethane, N -Methylmorpholine 2
Parts, stanas octoate 0.3 parts, water 3.5 parts, carbon black 1 part, and TDI-80 45 parts were rapidly stirred to obtain a polyurethane foam.

Comparative Example 3 100 parts by weight of polyoxypropylene triol of glycerin-propylene oxide (average molecular weight 3000, hydroxyl value 56) and triethylenediamine 33% dipropylene glycol solution 0.1.
3 parts, general-purpose silicone surfactant for flexible polyurethane foam 1.5 parts, stanna octoate 0.3 parts, water 3
Parts, carbon black 1 part and TDI (T-80) 40
A polyurethane foam made by rapidly mixing parts.

The above Examples 1 to 3 and Comparative Examples 1 to 3
In order to compare and evaluate the durability (weather resistance, moisture resistance) of each polyurethane foam created in 1.
m into a sheet shape, and this is cut with an air pressure press to 200
Thermoforming was performed at 30 ° C. for 30 seconds to prepare a sheet-shaped speaker edge material having a thickness of 1 mm.

The evaluation test method for the weather resistance of the material for the speaker edge was carried out at a black panel temperature of 63 ° C. using an ultraviolet long-life fade meter (Suga Test Instruments Co., Ltd., model FAL-5). A 100 mm x 60 mm sheet-shaped sample for evaluation was placed in the fade meter and taken out with time to obtain JIS K6.
The tensile strength was measured by the tensile test of 301.

The moisture resistance was evaluated by measuring the durability in steam at 120 ° C. using an autoclave. The evaluation sample is JIS K630 in advance.
The punched out No. 1 and No. 1 dumbbell shape is installed in the autoclave and taken out over time, according to JIS K63
The tensile test of No. 01 was performed to measure the tensile strength.

The sound quality was evaluated by the following test. Each of the foam materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was sliced into a sheet having a thickness of 7 mm, and heat was applied to a roll edge shape having a thickness of 0.7 mm and an outer diameter of 160 mm at 220 ° C. for 22 seconds. Molded. The speaker edge obtained in this way is used as a speaker (Nation
17PLO2A manufactured by al., JIS C553
The program source was reproduced using the standard closed box and driving amplifier specified in 1-4.2 and 4.4, and the sound quality was confirmed.

In the sound quality confirmation by the above-mentioned audibility, in Examples 2 and 3, a clean sound quality was reproduced with a very stable volume. (Table 1 ⊚ display) Although the sound quality of Example 1 was similar to that of Examples 2 and 3, the sound in the middle range was weaker than that of Example 1. (Table 1
(Display) Comparative Examples 1 and 3 were inferior to Example 1 and Comparative Example 2 in sound quality, and the sound in the middle frequency range was also weak. (Table 1
△ display)

At the same time, the output characteristics were measured based on the same JIS C5531. As a result, Example 2 and Comparative Example 2
And the output characteristic of 3 causes edge reverse resonance 500
The 1000 Hz portion is shown in FIG. Comparative Example 3 shows the largest drop due to reverse resonance, then Comparative Example 2 and Example 2 show the result with the smallest drop due to reverse resonance. This indicates that the speaker output of Example 2 has stabilized the output characteristics of the speaker.

Table 1 shows the results of comparative evaluation of the above-mentioned weather resistance, moisture resistance and sound quality by the above-mentioned hearing test.

[0032]

[Table 1]

[0033]

As is clear from Table 1 above, as the main raw material polyol, a compound selected from the group consisting of polyoxyalkylene polyol and its derivative having a hydroxyl group is added with an aromatic polycarboxylic acid anhydride. By using 25 to 85% by weight of the polyether polyester polyol, which is obtained by reacting with a compound having a cyclic ether group, based on the total polyol, excellent weather resistance is obtained as compared with the conventional speaker edge material of polyurethane foam. And moisture resistance can be satisfied at the same time. Further, the sound quality is improved by using the active hydrogen-containing organosilicon compound as the foam stabilizer.

[Brief description of drawings]

FIG. 1 is a graph comparing output characteristics of Example 2 and Comparative Examples 2 and 3 at a portion of 500 to 1000 Hz where edge reverse resonance occurs.

Claims (3)

[Claims] 1. A speaker edge material of polyurethane foam obtained by mixing a polyol, an organic diisocyanate, a foaming agent, a foam stabilizer, a catalyst and the like, wherein 25% by weight or more and 85% by weight or less of the polyol in the raw material. A polyether polyester polyol obtained by reacting a compound selected from the group consisting of polyoxyalkylene polyols and their derivatives having a hydroxyl group with an aromatic polycarboxylic acid anhydride and a compound having a cyclic ether group. Polyurethane foam speaker edge material. 2. The speaker edge of polyurethane foam according to claim 1, wherein the polyether polyester polyol is a polyether polyester polyol obtained by ring-opening polymerization of polyoxypropylene triol with phthalic anhydride and propylene oxide. Material. 3. The speaker edge material of polyurethane foam according to claim 1, wherein the foam stabilizer is an active hydrogen-containing organosilicon compound.