JPH05247810A - Fiber composite material - Google Patents

Abstract

PURPOSE:To provide a fiber composite material having excellent compression strength and flexural strength. CONSTITUTION:The objective composite material is a mat-shaped material having a thickness of 4mm and composed of three-dimensionally oriented glass fibers partially bonded with each other with a polyethylene in a state to hold a number of voids throughout the whole material. Glass fibers of 1mm long account for 5wt.% of the glass fibers of the composite material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber composite preferably used as a ceiling material for automobiles.

[0002]

2. Description of the Related Art Generally, a ceiling material for an automobile is lightweight,
Materials with excellent properties such as rigidity, heat resistance, sound absorption, and moldability are required.

Conventionally, as a material of this type, a porous fiber composite as disclosed in, for example, JP-A-1-156562 is known. That is, this fiber composite is one in which a mat-like material mainly composed of inorganic fibers is impregnated with a thermoplastic resin and the strength is exhibited by adhering and fixing the inorganic fibers adjacent to each other. A large number of pores communicating with voids inside are formed on both surfaces of the body, and both surface layer portions of the fiber composite have a thermoplastic resin more densely distributed than the inside and have a low porosity. It is a thing. Usually, the mat-like material used here has a large number of inorganic fibers oriented in the thickness direction by needle punching in order to develop the strength in the thickness direction of the product. Then, when this fiber composite was used as a ceiling material for automobiles, the whole body was heated again to a temperature equal to or higher than the melting point of the thermoplastic resin and shaped into a predetermined shape using a press molding method.

[0004]

However, when the above-mentioned conventional fiber composite is used as an automobile ceiling material, there arises a disadvantage that sufficient compressive strength and bending strength that can withstand the mounting process cannot be obtained.

That is, in the above-mentioned fiber composite, a mat-like material of inorganic fibers as a raw material is subjected to needle punching treatment to orient a large number of inorganic fibers in the thickness direction so as to develop compressive strength. In order to improve the compressive strength, it is desirable to sufficiently perform the needle punching treatment, but in this case, the punching treatment causes considerably large holes on the surface of the mat-like material. Then, this hole becomes the starting point of the breakage at the time of bending breakage, and the bending strength is reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a fiber composite having excellent compressive strength and bending strength.

[0007]

In the fiber composite of the present invention for solving the above-mentioned problems, inorganic fibers oriented in a three-dimensional direction are partially bound by a thermoplastic resin, and a large number of them are provided throughout the whole. A mat-like shaped product having a void of 1 to 20% by weight of the inorganic fibers, the short fibers having a length equal to or shorter than the thickness of the shaped product, and the short fibers are molded. It is designed to be oriented in the thickness direction of the body.

As the inorganic fiber used in the present invention, a mat-shaped product mainly composed of the inorganic fiber is used. Examples of the inorganic fiber include glass fiber, rock wool, and the like. When the thickness becomes thin, the mechanical strength decreases, and when the thickness becomes thick, the mechanical density decreases, and the bulk density increases, so 5 to 30 μm is preferable, and more preferable. Is 7-2
It is 0 μm.

As a method for producing the mat-like material, any method may be adopted, and examples thereof include a method of supplying inorganic fibers to a card machine, defibrating and knitting, and producing a mat-like material.

Further, thermoplastic organic fibers such as polyethylene, polypropylene, saturated polyester, polyamide, polyacrylonitrile, etc. may be added in order to bond the inorganic fibers or reduce the bulk density of the mat-like material.

As the fiber length of the inorganic fiber, a length of 30 to 100 mm is suitable from the viewpoint of moldability of the mat-like material, but in order to obtain the fiber composite of the present invention, the fiber to be obtained. Short fibers having a length equal to or less than the thickness of the composite must be added in an amount of 1 to 20% by weight based on the total amount of inorganic fibers. If the amount of the short fibers is less than 1% by weight based on the total amount of the inorganic fibers, the short fibers will not have a sufficient effect. On the other hand, if it exceeds 20% by weight, it becomes difficult to mold the mat-like material, and the effect of the short fibers is saturated, and conversely the resulting fiber composite becomes brittle. Therefore, the blending amount of this short fiber is 1 to 2 of the total inorganic fiber amount depending on the desired fiber composite.
It is preferable to add it by appropriately adjusting it in the range of 0% by weight.

As the short fibers, various kinds of materials can be used similarly to the above inorganic fibers. Further, even if the thickness of the short fiber is used, it is preferable to use a fiber based on the above-mentioned inorganic fiber. However, if the fiber length exceeds the thickness of the fiber composite to be obtained, it becomes difficult to orient in the thickness direction, so the fiber length must be less than this thickness. For example, when a fiber composite is manufactured as an automobile ceiling material, it is preferable to use short fibers having a length of 5 mm or less. Further, in order to express the reinforcing ability by the addition and orientation of short fibers, it is preferable to use one having a length of 0.5 mm or more.

Specifically, as the short fibers, commercially available milled fibers may be used, but it can be said that it is preferable from the viewpoint of product recycling that fine powder obtained by crushing a fiber composite with a crusher is used. Any method may be used for addition, for example, when a mat-like material is manufactured by a card machine, fine powder is dispersed and laminated on each layer of the card-like material constituting the mat-like material by a sprayer. There is a method.
The inorganic fiber and the short fiber may be made of the same material, or may be made of different materials and appropriately mixed and used.

After that, needle punching is preferably performed in order to improve the strength and the thickness recovery of the mat-like material, and the punch density is preferably 10 to 100 points per cm ² . This needle punching treatment is performed in order to increase the compressive strength of the product by orienting a large number of inorganic fiber mat-like products in the thickness direction, in addition to facilitating the handling of the mat-like product by entwining the inorganic fibers.

When the barb of the felt needle used at this time is made relatively large, the inorganic fibers can be shredded and shredded in the needle punching process, and as described above, short fibers are not added. It is possible to include short fibers in the mat-like material.

The thermoplastic resin used in the present invention is not particularly limited as long as it can bind the inorganic fibers and short fibers of the mat-like material to form a fiber composite. For example, thermoplastic resin films of polyethylene, polyamide, polyester, etc. are considered to be suitable.

That is, in order to obtain a fiber composite, first,
A thermoplastic resin film is laminated on both sides of the mat-like material to form a laminate.

Next, the laminate is preheated at a temperature equal to or higher than the melting temperature of the resin film used for this lamination.

Then, the preheated laminate is pressed and compressed by a press or a roll to impregnate the resin film into the mat-like material. At this time, the pressing pressure is 0.1 to
The compression time may be 20 kg / cm ² and the compression time may be 1 to 10 seconds. Further, when the rolls are compressed, it is preferable to set the distance between the rolls to 5% to 20% of the material thickness. When both the press and the roll are compressed, it is preferable that they are heated to a temperature equal to or higher than the melting temperature of the resin used.

When pressure-compressed in this way, the molten thermoplastic resin is impregnated into the inorganic fibers. afterwards,
When the pressure is released, the material tries to recover the original thickness, but the inorganic fiber is bonded to the impregnated resin, so the material thickness is not recovered sufficiently.

Therefore, it is preferable to go through a spreading process such as vacuum suction from above and below. Some of the short fibers contained in the material during this expanding step can be oriented in the thickness direction.

Finally, by keeping this thickness and cooling the whole, a fiber composite is obtained.

The fiber composite of the present invention thus obtained has a structure in which, in addition to the fibers oriented in the horizontal direction, a large number of fibers punched by needle punching and some of the short fibers are oriented in the thickness direction. Become. That is, short fibers having a thickness not more than the thickness of the fiber composite can be oriented in the thickness direction without being disturbed by other inorganic fibers during the expanding step, the compressive strength in the thickness direction is improved, and the bending property is also excellent. Becomes a fiber composite.

To shape the fiber composite of the present invention, reheating to a temperature above the melting temperature of the resin component and compression molding such as pressing may be performed. For example, compression molding is used for a ceiling material for automobiles. At this time, a cosmetic skin material such as vinyl chloride leather or a non-woven fabric may be laminated and shaped.

[0025]

According to the present invention, since the inorganic fibers contain 1 to 20% by weight of short fibers having a length equal to or less than the thickness of the molded product, the short fibers should be oriented in the thickness direction of the molded product. Becomes

[0026]

[Examples] Examples of the present invention and comparative examples for comparison will be shown below to clarify the reason why the present invention is excellent.

[0027]

Example 1 Preparation of Short Fibers Pieces of a fiber composite obtained by impregnating polyethylene into a mat-shaped material containing glass fibers as a main component were supplied to a pulverizer having a 3 mm screen to prepare fine powder. At this time, the average fiber length of the glass fibers in the fine powder was 1 mm. Preparation of mat-like material Glass fiber having a length of 10 to 100 mm and a diameter of 9 to 13 μm and high density polyethylene fiber having a length of 50 mm and a diameter of 30 μm are supplied to a fiber opening machine at a weight ratio of 2: 1 and then supplied to a card machine. The above-mentioned fine powder is spray-laminated with a sprayer on the card-like material created by. 20 layers of this card-like material are laminated to form a mat-like material. At this time, the amount of fine powder to be spray-laminated was 5% by weight of the total glass fiber amount. And 1
7m thick by needle punching 90 points per cm ^2.
A non-woven mat-like product having m and a weight of 450 g / m ² was obtained. Production of Fiber Composite After laminating a high density polyethylene film of MI5 having a thickness of 130 μm on both surfaces of the mat-like material, the whole is sandwiched between Teflon sheets and heated in an oven at 200 ° C. for about 3 minutes, and then at 210 ° C. Using a heated press at 4
It was compressed at a pressure of Kg / cm ² for 4 seconds to impregnate the inside of the mat-like material with the melted film resin. Next, while keeping the material temperature at 180 ° C., the Teflon sheet was vacuumed from both sides to expand the material thickness to 5 mm, and then the whole was cooled.

The sample thus obtained was heated again using an infrared heater until the material temperature reached 200 ° C., and then cold-pressed with a press having a spacer of 4 mm to make a test of a thickness of about 4 mm. I got a sample. Performance evaluation of fiber composites Various parts with different weights are taken from the obtained sample,
The flexural strength, flexural modulus, and compressive strength were measured, and the average value of 10 measurements was obtained. The results are shown in Table 1.

[0029]

Comparative Example 1 A fiber composite was produced in the same manner as in Example 1 except that the fine powder pulverized in Example 1 was not spray laminated. In the same manner, bending strength, bending elastic modulus,
The compressive strength was measured. The results are shown in Table 1.

[0030]

Comparative Example 2 A fiber composite was produced in the same manner as in Example 1 except that the average fiber length of the short fibers contained in the pulverized fine powder in Example 1 was 10 mm. In addition, flexural strength, flexural modulus and compressive strength were measured in the same manner. The results are shown in Table 1.

[0031]

Comparative Example 3 Example 1 except that the amount of short fibers laminated in Example 1 was 25 w / w% of the entire glass fiber.
A fiber composite was produced in the same manner as in. In addition, flexural strength, flexural modulus and compressive strength were measured in the same manner. The results are shown in Table 1.

[0032]

[Table 1]

As shown in Table 1, it can be said that the fiber composite of the present invention containing an appropriate amount of short fibers has improved bending properties and compressive strength.

[0034]

As described above, according to the fiber composite of the present invention, since the short fibers are oriented in the thickness direction of the molded product, the compressive strength and bending strength are improved.

Claims (1)

[Claims] 1. A mat-shaped molded body in which inorganic fibers oriented in a three-dimensional direction are partially bound by a thermoplastic resin and have a large number of voids throughout, A fiber composite characterized in that the inorganic fibers contain 1 to 20% by weight of short fibers having a length equal to or less than a body thickness.