JPH0762307B2 - Fiber molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fiber molding suitable as a ceiling material for automobiles.

(Prior Art) Light weight, rigidity, heat resistance, sound absorption,
Materials with excellent performance such as shapeability are required.

As a material of this type, for example, Japanese Patent Application Laid-Open No. 60-83832 discloses an automobile ceiling material in which a synthetic resin layer such as polyethylene is laminated on both surfaces of an inorganic fiber layer such as glass fiber. However, such a laminated molded product has a particularly low sound absorbing property and a small bending strength, and is insufficient as a ceiling material for automobiles, which is problematic.

(Problems to be Solved by the Invention) The present invention is to solve the above-mentioned problems, and an object of the present invention is to provide lightweight, rigidity, heat resistance, shapeability, sound absorption and bending strength. It is intended to provide a fiber molded article which is excellent in and suitable for a ceiling material for automobiles.

(Means for Solving the Problems) The fiber molded product of the present invention is a non-woven fiber mat-shaped molded product in which inorganic fibers are partially bonded by a binder and have a large number of voids throughout. As a result, a large number of pores communicating with the internal voids are formed on both surfaces of the molded body, and the binder is distributed more densely on both surface portions of the molded body than the inside and the porosity is high. It is characterized by being made low, which achieves the above objectives.

Examples of the inorganic fibers include, for example, glass fibers, rock wool, ceramic fibers, carbon fibers, etc., and the length thereof is preferably 10 to 200 mm from the viewpoint of the formability of a mat-like molded body, and 50 mm or more is 70 weight. % Or more is more preferable. Further, the thickness is preferably 3 to 30 μm, more preferably 5 to 20 μm, since the mechanical strength decreases as the thickness decreases, and the bulk density decreases as the thickness increases.

The binder may be any one that can bind the inorganic fibers to each other, and examples thereof include thermoplastic resins such as polyethylene, polypropylene, saturated polyester, polyamide, polystyrene, polyvinyl butyral, and polyurethane, unsaturated polyester, and phenol resin. Examples include thermosetting resins.

The form of the binder may be any form such as fiber, powder, solution, suspension, emulsion, film,
It is used in a suitable form depending on the method for producing the fiber molded article of the present invention.

The ratio of the inorganic fiber and the binder is less the binding portion when the amount of the binder is small, the mechanical strength of the molded article is reduced, and conversely when the amount is large, the porosity is reduced, so the weight ratio is 1: 4.
~ 4: 1 is preferred.

The fiber molded product of the present invention is a non-woven fiber mat-shaped molded product in which the above-mentioned inorganic fibers are partially bonded by a binder, and has a large number of voids throughout, and its density becomes heavier and heavier, If it becomes smaller, the mechanical strength will decrease, so 0.01 to 0.
2 g / cm ³ is preferable, and the total porosity is preferably 70 to 98%.

In addition, a large number of pores communicating with internal voids are formed on both surfaces of the molded body, but the pore diameter is mostly 2 to 50 μm.
However, the pore density is preferably 1 to 10 holes / cm ² .

Furthermore, the binder that binds the above-mentioned inorganic fibers is more densely distributed in the surface portion than the inside of the molded body, and the porosity of the surface portion is made lower than the inside, but It is preferable that the porosity is 50 to 95% and the internal porosity is 85 to 99%.

The thickness of the molded body may be appropriately determined depending on the application, but is generally 4 to 200 mm, and preferably 4 to 12 mm when used as a ceiling material for automobiles.

Although the constitution of the fiber molded body of the present invention is as described above, it is adhered to the surface of the molded body so that a film, a foam sheet, a metal plate or the like is laminated on the molded body or the molded body is easily adhered to other articles. Agents or adhesive layers may be laminated, and foams or non-woven fabrics such as polyethylene foam, polypropylene foam, polyurethane foam, rubber foam, etc. having closed or open cells, woven cloth, vinyl chloride leather, etc. You may laminate a cosmetic skin material.

An example of the method for producing the fiber molded body of the present invention will be described below.

First, in order to obtain a mat-shaped molded product, inorganic fibers are supplied to a card machine and defibrated to form a mat. At this time, if a fibrous binder is mixed, it becomes easy to form a mat. Therefore, it is preferable to add 10 to 30% by weight of the fibrous binder in the molded product.

Also, may be strained facilities needle punching in order to improve the mechanical strength of the mat-like molded body, a needle punch is 1 cm ²
It is preferable to carry out at 1 to 3 places.

Further, a powdery binder may be mixed when defibrating to uniformly bind the inorganic fibers, or a powdery binder or an emulsion of the binder, after matting or after needle punching, You may spray suspension etc.

Next, a thermoplastic resin sheet, which is a binder, is laminated on both surfaces of the obtained mat-like molded body, the laminate is heated to the melting temperature of the thermoplastic resin sheet, and compressed while keeping this temperature. This compression pressure is 0.1-5 kg / cm ² , compression time is 1-30
A range of seconds is preferred.

Finally, the above temperature is maintained to release the compression, the thickness of the non-woven fiber mat is restored by the elasticity of the inorganic fibers, and then the non-woven fiber mat is cooled. If this recovery amount is insufficient or it takes a long time,
The thickness may be forcibly restored by blowing heated air into the interior or separating both surfaces by vacuum adsorption.

In the above process, the thermoplastic resin sheet is melted, compressed, and impregnated into the inside of the non-woven fiber mat-shaped molded product.
When the inorganic fibers are mixed with a fibrous or powdery binder, these binders are also melted to bond the inorganic fibers.

At this time, if the compression is released before the molten resin of the thermoplastic resin sheet is uniformly impregnated to the inside by controlling the compression pressure and the compression time, the above-mentioned molten resin is more densely impregnated in the surface portion than in the inside. , The inorganic fibers are firmly bonded to each other at the crossing portion with the melt of the above-mentioned binder, and a large number of pores are formed on the surface, and the fiber molding of the present invention having a large number of voids throughout is formed. can get.

Further, as described above, instead of laminating the thermoplastic resin sheet on both surfaces of the non-woven fiber mat-like molded article, a thermosetting resin such as unsaturated polyester resin or phenol resin thickened with a thickener such as silica is used. It is also possible to obtain the fiber molded product of the present invention by applying the composition and then heating and compressing the applied product in the same manner as described above.

Although it may be shaped during the above heating and pressing, when the binder is a thermoplastic resin, it is formed into a plate during the above heating and pressing and is heated again when used. You may press and shape. In particular, when used as a ceiling material for automobiles, it is preferable that it is formed as a plate-like body, and a foam or a cosmetic skin material is laminated and supplied to a metal mold for deformed shape, heat-bonded and shaped.

(Function) In the fiber molded product of the present invention, the inorganic fibers, the binder binding the inorganic fibers, and a large number of voids are present, and moreover, the binder is densely distributed on both surface portions and the void ratio is higher than the inside. Is low, it is lightweight, has excellent rigidity, heat resistance, and shapeability, and in particular, significantly improves bending strength.

Also, due to the presence of pores on both surfaces, a large number of voids, and inorganic fibers, when sound is incident, there is little reflection, and the sound enters almost all the voids inside. Then, the inorganic fibers vibrate, absorb sound wave energy and convert it into heat energy, and significantly improve sound absorption.

(Example) Next, the Example and comparative example of this invention are shown.

Example 1 450 g of glass fiber (diameter 10 μm, length 50 mm) and high-density polyethylene fiber (diameter 30 μm, length 50 mm, melting point 135 ° C.) 150
g was mixed, defibrated with a card machine to form cotton, and needle punched to obtain a non-woven fiber mat with a thickness of 8 mm and 1 m ² .

A high density polyethylene sheet (thickness 100 μm, melting point 135 ° C.) was laminated on both sides of this non-woven fiber mat,
After heating at 0 ° C. for 3 minutes, it was pressed into a flat plate at a pressure of 1 kg / cm ² with a press at 200 ° C. At this time, the thickness of the laminate is 2 mm
Met.

Then, the clearance of the press was raised to 6 mm and cooled to obtain a flat plate-shaped fiber molded body having a thickness of 6 mm. The average porosity of this fiber molding is 90%, the porosity of the surface part is 70%, the porosity of the central part is 95%, the surface pore density is 5 / cm ² , and the pore diameter is 2-100 μm, and most of them are Was 30 to 40 μm. Bending test according to JIS K 7221 for this fiber molding (sample width
50 mm, length 150 mm), and the sound absorption coefficient was measured by the vertical incidence method according to JIS A 1405. The results are shown in Table 1.

Comparative Example 1 The high-density polyethylene sheet (thickness 100 μm, melting point 135 ° C.) used in Example 1 was laminated on both sides of the non-woven fiber mat (thickness 8 mm, 1 m ² ) used in Example 1, and this lamination was performed. 200 ℃
After heating for 3 minutes at 25 ° C, press machine at a clearance of 6 m
A pressure was applied at m, and the state was maintained and cooled to obtain a laminated molded body having a thickness of 6 mm in which high density polyethylene sheets were laminated and adhered to both surfaces of the non-woven fiber mat.

The bending test and the sound absorption coefficient by the normal incidence method were measured for this laminated molded body in the same manner as in Example 1. The results are shown in Table 1.

(Effects of the Invention) Since the fiber molding of the present invention is configured as described above, it is lightweight and excellent in rigidity, heat resistance, shapeability, and sound absorption. In particular, it is remarkably excellent in sound absorption and bending strength,
It is suitable as a ceiling material for automobiles.

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

Claims (1)

[Claims] 1. A non-woven fiber mat-shaped molded product, comprising inorganic fibers partially bonded with a binder, and having a large number of voids throughout, the inner surface of which is formed on both surfaces of the molded product. A fibrous molded article characterized in that a large number of pores communicating with voids are formed, and a binder is more densely distributed than in the interior on both surface portions of the molded article, and the porosity is low.