JPH0677937B2 - Method of forming soundproofing material for automobiles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for forming a soundproofing material applied to an automobile dash part, and can realize weight reduction without impairing soundproofing characteristics such as sound absorption and sound insulation. The present invention relates to a method for forming a soundproof material for automobiles.

2. Description of the Related Art Conventionally, in order to prevent noise generated in the engine room of an automobile from entering the vehicle interior side, various soundproofing measures have been taken, for example, on the vehicle interior side of a dash panel. As one of them, a soundproof material in which a skin and a porous material are integrated is applied, but the conventional skin has almost the same thickness regardless of the distance from the engine.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, from the viewpoint of energy saving, it is required to reduce the weight of the vehicle body, and thus to reduce the weight of each component, and to reduce the weight of the soundproofing material. Was wanted.

Means for Solving the Problems Therefore, the present inventors can efficiently exhibit the performances such as sound insulation and sound absorption of the soundproof material composed of the skin and the porous material, without impairing the soundproof property at all, As a result of earnest research to develop a soundproofing material that can reduce the weight, if the skin of the upper part is thinner than that of the lower part, and the lower part is thinner than the steering part, the soundproofing characteristics are not affected at all. The inventors of the present invention have found that the weight can be reduced for the thinned portion, and have arrived at the present invention.

The present invention relates to a method of forming using a mold of a soundproof material in which a porous material and a skin which are provided on the interior side of a car dash portion are integrated, in which a recess for skin formation is made deeper in a lower portion as compared with an upper portion, and steering is performed. The soundproofing for automobiles is characterized by injecting the undiluted solution for the skin into a mold with a deeper part, forming the lower part thicker than the upper part and the steering part thicker than the lower part, and then integrating with the porous material. A method of forming a material is provided.

Next, the present invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 shows a soundproof material 1 for a dash portion of an automobile, which comprises an upper portion 2 far from the engine, a lower portion 3 close to the engine, and a steering portion 4 having many holes. Reference numeral 5 is a through hole for a steering shaft, a wire and the like.

The dash soundproof material 1 is composed of a porous material 7 and a skin 8.

The porous material 7a of the upper portion 2, the porous material 7b of the lower portion 3 and the porous material 7c of the steering portion 4 are all formed to have the same thickness, but the skins corresponding to them are the upper portions. The skin 8b of the lower portion 3 is thicker than the skin 8a of No. 2 and the skin 8c of the steering portion 4 is thicker than this.

A molding die is used to form the soundproofing material, and the skin to be injected into the molding die and molded contains a binder such as a synthetic resin, rubber, and a bituminous substance, and a filler.

Examples of the synthetic resin include urethane resin, petroleum resin, polyethylene resin, polypropylene resin, ethylene-vinyl acetate copolymer resin, and rubber components such as natural rubber, polybutadiene, ethylene-butadiene rubber, butyl rubber, neoprene rubber, and chloroprene rubber. Examples of the synthetic rubber and the bituminous material include one kind or a mixture of two or more kinds such as straight asphalt, blown asphalt, and semibron asphalt.

Other fillers contained as main components are talc, clay,
It is preferable to use calcium carbonate, waste fiber defibrated material, fibrous material such as slug wool, scaly material such as mica and mica, and any inorganic filler such as silicone, or a mixture thereof, together with an organic filler. When used, synthetic resin powder, synthetic fiber scraps, etc. are used.

Examples of the porous agent integrated with the skin include bulky nonwoven fabric and urethane foam material. The bulky non-woven fabric is formed by forming a fleece having a predetermined thickness by mixing a discontinuous fiber material and a thermosetting resin as a binder,
Examples of the discontinuous fiber material include synthetic resin fibers such as viscose rayon, acetate, acrylic, nylon, polyester and vinyl chloride, and animal and vegetable fibers include wool, cotton and hemp. Examples of the mineral fiber include fiber materials such as glass wool, rock wool and asbestos fiber. Needless to say, a fiber material obtained by opening industrial waste such as fluff, cotton fluff, and fiber waste can also be preferably used.

A bulky nonwoven fabric is formed by using these fiber materials, a binder, an epoxy resin as a moldability-imparting resin, a urethane resin, a phenol resin, a thermosetting acrylic resin, and the like.

The manufacturing process in the case of manufacturing a bulky nonwoven fabric may be a conventionally known process, and as an example, the fiber material is first opened with a bale feeder to form a web of a considerable thickness with a wrapper, and the formed web is formed. Disperse the thermosetting resin powder component with a resin spraying machine, open the fiber again with a beater in the homing machine and mix with the resin powder again and make a fleece with a desired thickness again with a wrapper and sequentially flow on the net conveyor of the heating furnace. Go. The obtained fleece may be heated and pressed by a molding machine as it is, or heated in a heating furnace for easy handling and taken out in a semi-cured state in which a part of the mixed resin powder is cured and heated and pressed. Alternatively, the mixed resin powder may be sufficiently cured to be taken out as a felt-like material having excellent elasticity and looseness.

For urethane foam material, inject urethane stock solution into the mold,
Although it is formed by foaming, the undiluted solution is prepared by reacting a polyisocyanate compound and a polyol as a main component with an auxiliary agent such as a foaming agent, a catalyst, a foam stabilizer and a crosslinking agent. Furthermore, it is also preferable to add asphalt or rubber to these stock solution components in order to improve the soundproofing effect.

As the polyisocyanate component, tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), 1,5
-Naphthylene diisocyanate (NDI), hexamethylene diisocyanate (HDI), hydrogenated TDI, hydrogenated MDI, isophorone diisocyanate (IPDI), lysine isocyanate (LDI), isopropylidene bis (4-cyclohexyl isocyanate) (IPCI), etc. Any of the above diisocyanates can be used.

As the polyol, polyether polyol, polyester polyol, polymer polyol, polycarbonate diol and the like can be used.

As the catalyst, it is preferable to use an organometallic compound such as an organotin compound or an organolead compound and triethylenediamine in combination with other amine compounds, or to use alone, and particularly, a tin salt of a carboxylic acid or an organotin salt. It is preferable to use an organotin compound and a tertiary amine compound.

The foaming agent to be blended is, for example, trichlorofluoromethane,
Dichlorodifluoromethane, methylene chloride, other halogenated hydrocarbons and water can be used. It is also possible to use a foam stabilizer such as an organic silane compound together with the foaming agent.

As other additives, cross-linking agents such as diethanolamine and triethanolamine, flame retardants, colorants, stabilizers and the like can be used.

The soundproofing material forming method of the present invention can be realized by using a molding die in which the recess of the skin molding die is deeper in the lower portion than in the upper portion and the steering side is deeper.

The molding of the soundproof material skin is performed by making the concave part of the mold deepest in the steering part, then making the lower part and the upper part shallower in this order, thickening the steering part, making the lower part thinner than this,
Since the upper part can be made the thinnest, the skin nearer to the engine is thicker and the soundproofing effect is exhibited as much as necessary, and even if it is thin, the place that can be thinned can be thinned,
The overall weight can be reduced.

Example An example will be described below with reference to FIGS. 2 and 3.
Naturally, the invention is not limited to the following examples.

First, in order to form the skin 8 shown in FIG. 2, 100 parts by weight of polyether polyol as a polyol component and ethylene glycol as a cross-linking material are used in an injection molding die in which a lower portion is deeper than an upper portion and a steering portion is deeper than an upper portion. 1
5 parts by weight, 2 parts by weight of triethylenediamine as a catalyst,
0.5 parts by weight of dibutyltin dilaurer as a metal catalyst and 80 parts by weight of modified MDI as an isocyanate component were injection-molded in a mold.

The resulting weight of the epidermis, the upper portion 2.5 kg / m ² lower part 3.5 kg / m ^2, a steering part 5 kg / m ^2, the total weight was 3.6 kg.

On the skin, 100 parts by weight of polyether polyol and 3 parts of water
A urethane foam stock solution consisting of 1 part by weight, 0.3 parts by weight of amine catalyst, 1 part of foam stabilizer, 3 parts by weight of diethanolamine and 30 parts by weight of crude MDI is injected and foamed to form the porous materials 7a, 7b, 7c shown in FIG. Then, these were integrated with the epidermis 8.

Comparative Example A skin having the same composition as in the example was injection-molded in an injection-molding die having the same depth of the recess as conventionally used. The obtained skin weight was 4.0 kg as a whole.

Onto the surface skin, the same urethane foam material stock solution components as in Example were injected and foamed to be integrated.

Next, the soundproofing effect was investigated by the following method.

Test method Fig. 2 A dashboard 1a with nothing attached, a soundproof material of the example bonded to this dashboard, and a soundproof material of the comparative example bonded to the dashboard in the same manner Is mounted on the actual vehicle, and the frequency of 100 to 500 is obtained when the vehicle is fully accelerated in the third gear.
The noise level of 0 Hz was measured as an average value by a 1/3 octave analyzer, and from the noise level of the state, the state,
The noise level difference from the reference state was obtained by subtracting each noise level of each state, and this was expressed as a soundproofing effect in the unit dB in the graph of FIG. The solid line is for the example of the state, and the dotted line is for the comparative example of the state.

From the results of FIG. 3, it can be seen that the higher the soundproofing effect is, the larger the numerical value is, and therefore the soundproofing effect of the example is superior to that of the comparative example.

EFFECTS OF THE INVENTION According to the present invention, the porous material and the skin are integrally molded by using a molding die, and at this time, the thickness of the skin is made thicker in the order of the steering portion, the lower portion, and the upper portion, so that the molding can be performed. It is possible to provide a soundproofing material that can optimally prevent the sound of the engine at the position where it is received, and also to reduce the weight of the thinned skin portion, thereby contributing to energy saving.

[Brief description of drawings]

FIG. 1 is a front view of a dash portion of an automobile using a soundproof material according to an embodiment of the present invention, and FIG. 2 is a soundproof material of FIG.
A sectional view and FIG. 3 are measurement graphs of the soundproof effect of this soundproof material and the comparative example. In the figure, 1 is soundproof material for dash part, 2 is upper part, 3 is lower part, 4 is steering part, 7 is porous material, 8 is skin, 8a is skin of upper part, 8b is skin of lower part, 8c is a skin of the steering section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuyasu Nakamura 1-4-1 Chuo, Wako-shi, Saitama, Honda R & D Co., Ltd. (72) Inventor Hiroshi Suzuki 2-12-19 Nitta, Adachi-ku, Tokyo No. (72) Inventor Hideo Fujii 450-4 Kuzume, Washinomiya-cho, Kitakatsushika-gun, Saitama Prefecture

Claims (1)

[Claims] 1. A method of forming using a mold of a soundproof material, which comprises a porous material and a skin, which are provided on the vehicle interior side of an automobile dash, wherein a recess for skin formation is made deeper in a lower portion as compared with an upper portion, For automobiles characterized by pouring the stock solution for skin formation into a mold with a deeper steering section to form a thicker lower section than the upper section and a thicker steering section than the lower section, and then integrating it with a porous material Soundproofing material formation method.