JPS6335863A - Fiber sheet molded body - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention is lightweight, high strength, heat resistant, and formable.

This invention relates to a molded article with excellent sound absorption properties, particularly a fiber sheet molded article useful as a ceiling material for automobiles.

(Prior Art) Cardboard and various resin foams are used for molded ceilings, which are one of the interior materials of automobiles.

Cardboard is lightweight and inexpensive, but since the only means of shaping is compression, it has poor formability and cannot be shaped into delicate shapes. Furthermore, it has the disadvantage of poor shape retention due to its hygroscopic properties. For this reason, resin foams are widely used.
No. 4 and Japanese Patent Publication No. 58-2811 disclose molded ceilings using modified polystyrene foam. Such molded bodies are obtained by foaming resin and molded into the desired shape, so they have excellent shapeability, and the molded bodies obtained are relatively strong and lightweight, and have excellent heat insulation and heat resistance. . However, since thermoplastic resin is used, the dimensional stability and strength at high temperatures are poor. moreover.

Since closed-cell foam is used to obtain a heat-insulating effect, sound reflection occurs on the surface, making it impossible to obtain a sufficient sound-absorbing effect.

In order to improve the strength of such molded ceilings, reinforcing materials are laminated, and in order to obtain a sound absorption effect, sound absorbing materials are laminated or through holes are provided in the base material (Japanese Patent Laid-Open No. 5
5-11947, Japanese Patent Application Laid-Open No. 53-14074, and Japanese Patent Publication No. 57-60944).

The manufacturing process becomes complicated and costs increase. Another drawback is that the weight of the molded ceiling itself increases, reducing the fuel efficiency of the vehicle.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional drawbacks, and aims to achieve light weight and high strength.

It has excellent formability, heat resistance, heat insulation and sound absorption properties, as well as strength and dimensional stability at high temperatures.

The object of the present invention is to provide a molded body suitable for molded ceilings of automobiles.

(Means for Solving the Problems) The fiber sheet molded article of the present invention is obtained by heating and compression molding a nonwoven fabric base material in which expandable resin particles are dispersed in fibers mainly composed of inorganic fibers, This achieves the above objective.

The fibers used in the nonwoven fabric serving as the base material of the molded article of the present invention are mainly composed of inorganic fibers, and optionally contain n-type fibers in a proportion of 50% by weight or less. Examples of such inorganic fiber materials include glass and rock wool, and examples of organic fiber materials include polyethylene and polypropylene.

If the content of organic fiber exceeds 50% by weight, the strength of the molded product obtained will decrease. All of these fibers are short fibers with a diameter of 2 to 40 μm and a length of 50 to 200 m1.

If the fiber diameter or fiber length is less than the range specified in 2 above, the strength of the obtained molded product will be insufficient, and the above-mentioned 〒il! If the value exceeds the range, shapeability during molding will be poor.

The expandable resin particles contained in the nonwoven fabric are thermoplastic resin particles impregnated with a blowing agent, and have the property of melting and foaming when heated above the melting point of the thermoplastic resin. As for the thermoplastic resin used.

Examples include polystyrene. As a foaming agent, butane,
A volatile solvent such as pentane 2 freon or carbon dioxide gas is used. Such expandable resin particles.

The particles made of the thermoplastic resin can be obtained, for example, by immersing the particles in the volatile solvent in an autoclave.

When resin particles are immersed under high pressure in an autoclave, volatile solvents enter the resin. Even when the resin particles are returned to normal pressure, the solvent that has entered and become trapped inside the two particles does not substantially volatilize or disappear. The particle size of the expandable resin particles thus obtained is 1. It is up to about Ou+.

Its shape is not particularly limited. The lower limit of the available particle size is usually 0.01 mm, but there is no limit.

When the particle size exceeds 1.0 mm, it becomes difficult to uniformly disperse the particles in the nonwoven fabric that is the base material.

The foaming rate of the expandable resin particles is 10 times or more, preferably 20 times or more.
That's more than double that. If it is less than 10 times, the heating and
The binder function to bond the fibers of the base material to each other during molding is insufficient, resulting in a decrease in the strength of the molded product obtained. Although the upper limit of the expansion rate of the expandable resin particles is not particularly limited, the upper limit of the expansion rate that can be produced by such expandable resin particles is about 80 times. Polymer material, particle size, blowing agent type, blowing agent impregnation amount, etc. are appropriately selected so that the foaming rate of the expandable resin particles is 10 times or more.

Such expandable resin particles account for 20 to 20% of the total fibers used (including inorganic fibers and optionally organic fibers).
It is contained in the base material at a ratio of 120%. If it is too small, the resulting molded product will have insufficient strength, and if it is too large, it will be difficult to prepare the base sheet. The nonwoven fabric that is the base material of the molded article of the present invention is prepared using the above-mentioned inorganic fibers (1) expandable resin particles and, if necessary, organic fibers (2) according to a conventional nonwoven fabric manufacturing method. For example, first, glass fibers commercially available in the form of yarn chops, roving chops, etc. are opened. When using organic fibers, they are similarly opened into filaments, and this glass fiber (inorganic fiber)
2. Expandable resin particles and, if necessary, organic fibers are thoroughly blended using a card machine or the like, and compression molded to obtain a nonwoven fabric.

The porosity of such a nonwoven fabric is 92-99.5%.

If it falls below 92%, it will be used in the heating and molding process described below.

Even when the expandable resin particles are foamed, the molten resin cannot sufficiently penetrate between the fibers, and as a result, the effect of the binder to firmly fuse the fibers together cannot be obtained. In other words,
The strength of the resulting molded product will be insufficient. If the porosity is too high, it will be difficult to maintain the shape of the nonwoven fabric, and the strength of the resulting molded product will also decrease. The thickness of the nonwoven fabric varies depending on the thickness and density of the intended molded product, but is usually 10 to 1.
00mm.

Preferably it is 10-60 mm. If it is less than 10 via, the strength of the molded ceiling as a whole is insufficient,
If the length exceeds 100 m, it will be difficult for heat to be transmitted to the center during heating, which will be described later, and a large amount of heat will be required.

The base material (nonwoven fabric) obtained in this manner is cut to an appropriate size, heated, and pressure-molded using a pair of molds having convex and concave shapes of a desired shape by a conventional method.

The heating temperature is equal to or higher than the melting point of the resin used for the expandable resin particles in the base material. Usually, the temperature is set at about 20 to 150°C higher than the melting point in order to melt and foam in a short time. For example, when the fiber material of the base material is glass and the material of the expandable resin particles is polystyrene, the heating temperature is 100° C. or higher and usually about 200° C. The temperature of the mold is 2 below the melting point of the expandable resin particles 2 and usually from room temperature to about 80°C. The compression force is usually 0.3 to 30 kg/cd, and the compression time is 10 seconds to 5 minutes. In this way,
A molded body compressed to a thickness in the range of 0.05 to 0.7 times the thickness of the original base material is obtained. (The thickness of the molded body is 1 to 20 mm.
).

For example, in the case of ceiling materials for automobiles, the strength is 0.05 to 0.3 times the original thickness at the periphery where strength is particularly required.The periphery does not require sound absorption or cushioning properties. The central part is compressed to 0.2 to 0.7 times its original thickness. The thickness of the peripheral part of such a molded body is about 1 to 3 fl,
The central part is 4-10+++-. When molded to a thickness 0.7 times or more (low density), sufficient adhesion between fibers cannot be obtained due to foaming and assimilation of the expandable resin particles, resulting in insufficient strength of the molded product.

Conversely, if it is 0.05 times or less, there is no particular problem, but it is wasteful because a large force is required for compression. The porosity of the central portion is about 50% or more, and such a molded body has excellent sound absorption properties.

An interior decoration material made of m-cloth, nonwoven fabric, plastic sheet, etc. is adhered to the surface of the molded product for automobile ceilings obtained by such a method. The base material and the interior decorative material may be laminated, heated, and integrally formed.

The molded article of the present invention is prepared, for example, in the following manner. As shown in FIG. 1, spread fibers 11 (inorganic fibers and, if necessary, organic fibers) stored in a fiber supply container 1 are supplied onto a belt conveyor 12 in predetermined amounts. This fiber 1 is supplied to a card machine 2 and thoroughly mixed. A foamable resin particle supply container 3 containing foamable resin particles 31 is connected to the card machine 2, and the foamable resin particles 31 are supplied from the container to the card machine 2, and the fibers 1
1 and thoroughly mixed. This mixture of fibers 11 and expandable resin particles 31 is formed into a continuous nonwoven fabric 120 by a card machine 2 and wound up by a two-winder 4.

The wound nonwoven fabric 120 is cut into a desired size. As shown in FIG.
1 to the heating furnace 5. The laminate 10 heated and foamed in the heating furnace 5 is then compression-molded using a molding die 6 in a conventional manner to obtain a molded body 100.

(Function) The fiber sheet molded article of the present invention is a nonwoven fabric base material in which expandable resin particles are dispersed in fibers mainly composed of inorganic fibers.
Obtained by compression molding. The thermoplastic resin of the expandable resin particles contained in the base material is softened and dissolved in the heating process. As a result, volatile solvents and the like in the two particles are vaporized and foaming occurs. Since the expandable resin particles are uniformly dispersed in the base material, they foam uniformly in the base material. When this base material is compressed with a mold, the melted and foamed resin derived from the expandable resin particles sufficiently penetrates between the fibers of the base material. When the temperature drops, this resin hardens and acts as a binder, binding the fibers together. in this way.

This is because the fibers are fixed to each other by resin.

Excellent strength and shape retention. Due to the use of inorganic fibers, its thermal stability is much higher compared to conventional thermoplastic foams.

The molded article of the present invention is lightweight because it is obtained from a relatively low-density nonwoven fabric base material. The density of the molded body varies depending on the part; for example, the peripheral part of an automobile ceiling has a high density because it is sufficiently compressed and molded, and the central part has a low density because the degree of compression is small.

The high-density part has particularly high strength, and the low-density part has elasticity and a high sound absorption effect.

As described above, the molded article of the present invention has the above-mentioned various excellent properties, so it is a reinforcing material that has been needed in the past.

Sound absorbing materials are not required. Therefore, the process for manufacturing the automobile ceiling is simplified, and the weight of the ceiling itself is also reduced.

(Example) The invention will be explained below with reference to examples.

Preparation of molded body: Fiber glass fiber (diameter 13 μm, fiber length 5-20 cm)
) ・=90 parts by weight polypropylene fiber (diameter 18 μm.

Fiber length 5-20cm)...10 parts by weight Expandable resin particles Nistyropeace (manufactured by Building Blocks Chemicals ■; polystyrene particles impregnated with butane, diameter 0.2-0.8, foaming ratio 30 times).
...50 parts by weight Decorative material for interior: Polyester nonwoven fabric (thickness 1.5 m) The above inorganic fiber (glass fiber), organic fiber (polyester fiber), and foamable resin particles were used.

A rolled nonwoven fabric having a width of 1300 m and a length of 30 m was prepared using the apparatus shown in FIG. The thickness and porosity of this nonwoven fabric are shown in the table below. This nonwoven fabric has a width of 1150 mm.

It was cut to a length of 1,400 squares, the above-mentioned interior decoration material of the same size was laminated thereon, and the two peripheries were pinched with clamps. As shown in Fig. 2, after heating this laminate in a hot air heating furnace at 180°C for 3 minutes, immediately using a mold at a temperature of 30°C,
Compression molding was performed for 1 minute with a compression force of l kg/c++I. The minimum thickness of this mold is 2.9u+.

The maximum thickness part was designed to be 8.0 fins, and the obtained molded product almost corresponded to the shape of this mold.

CB) Performance evaluation of molded body: After the molded body obtained in section (A) was held in a hot air open at 95°C for 4 hrs.

The original thickness of the molded body is 2.9, and the original thickness of the dragon part is 8.
The thickness of the H portion was measured and the rate of change (%) was calculated. Separately, from the molded body obtained in section (A), a thickness of 3 m,
A sample piece with a width of 30 mm and a length of 150 mm was cut out and its bending strength was evaluated. First, the above sample piece was
It is placed on a pair of supports spaced apart by +. Next, force is applied to the center of this sample piece at a speed of 50 m/min. and.

The weight of the sample piece was measured when it was bent. Further, from the molded body obtained in Section 5 (8), a thickness of 8 fins and a width of 50 (bm) was obtained.

A sample piece with a length of 500 μl was cut out and 1
The sound absorption coefficient at 00011z was measured. The respective results are shown in the table below. In the section of bending strength in the table below.

The circle is 10 kg/cI+! Above, Δ is 9.9~
6 kg/cut.

And × is 5.9kg/co! The following is shown. Example 2~
The results of Comparative Examples 7 and Comparative Examples 1 to 6 are also shown in the table below.

1 Execution ± 1 The same as Example 1 except that the expandable resin particles were used at a ratio of 115% based on the weight of the fibers.

x Storm amount The same as Example 1 except that the main expandable resin particles were used at a ratio of 25% based on the weight of the fibers.

The procedure was the same as in Example 1 except that the thickness of the nonwoven fabric base material was 60 mm.

Example 1 Same as Example 1 except that the porosity of the nonwoven fabric base material was 93% and the thickness was 12 m1.

The same as Example 1 except that the porosity of the nonwoven fabric base material was 99.4% and the thickness was 60 mm.

The procedure was the same as in Example 1 except that the weight ratio of glass fiber and polypropylene fiber was 1:l.

This comparison is the same as Example I except that polystyrene particles having the same particle size were used instead of the upwardly expandable resin particles.

Comparison I The same as Example 1 except that the expandable resin particles were used at a ratio of 15% based on the weight of the fibers.

Above comparison ±1 Example 1 except that the porosity of the nonwoven fabric base material was 91%
It is similar to

Comparison ↓ The same as Example 1 except that the porosity of the nonwoven fabric base material was 99.7%.

It is the same as Example 1 except that the thickness of the nonwoven fabric base material is 9 mm.

The procedure was the same as in Example 1 except that the nonwoven fabric base material was prepared using only polypropylene fibers.

(Left below) (Effects of the Invention) According to the present invention, it is lightweight, has high strength, has excellent formability, heat resistance, heat insulation and sound absorption, and has strength and dimensional stability at high temperatures. A fiber sheet molded article with excellent properties can be obtained. Such molded bodies are particularly suitable for automobile ceiling materials.

When the molded article of the present invention is used as an automobile ceiling material, conventionally.

This eliminates the need for reinforcing materials, sound-absorbing materials, etc. required for automobile ceiling materials. Therefore, the manufacturing process is simplified. Since the molded body itself is manufactured using an hour wheel, automobile ceiling materials can be supplied at low cost. Since no reinforcing materials are required, the ceiling itself is lighter, reducing fuel consumption.

The molded product of the present invention can be used not only as a ceiling material for automobiles but also in many fields such as ceiling materials for houses and ships, and building materials for heat insulation.

- Riichizu I! 11-W Kai FIG. 1 is a schematic diagram showing the process of preparing a nonwoven fabric serving as a base material, and FIG. 2 is a schematic diagram showing a process of preparing a molded article using the obtained base material.

1... Fiber supply container, 2... Card machine, 3...
- Expandable resin particle supply container, 5... Heating furnace 26...
Mold.

11... Spread fiber, 31... Expandable resin particles, 1
2...Nonwoven fabric.

100... Molded object.

that's all

Claims (5)

[Claims] 1. A fiber sheet molded product obtained by heating and compression molding a nonwoven fabric base material in which expandable resin particles are dispersed in fibers mainly composed of inorganic fibers. 2. The molded article according to claim 1, wherein the expandable resin particles are thermoplastic resin particles impregnated with a foaming agent. 3. The molded article according to claim 1, wherein the inorganic fiber is glass fiber. 4. The molded article according to claim 1, wherein the fibers contain organic fibers in a proportion of 50% by weight or less. 5. The molded article according to claim 1, which is obtained by laminating an interior decorative material on one side of the base material, heating, and compression molding.