JPH01281923A - Glass fiber reinforced composite body for molding airtight product - Google Patents

Abstract

PURPOSE:To obtain a molded item with simple composition which has airtightness and high strength by a method wherein 35-60wt.% of mat-like glass fibers to total weight is impregnated with resin mainly consisting of crystalline ethylene-propylene random copolymer, the ethylene content of which is 2-6wt.%. CONSTITUTION:A mat-like glass fiber, which is reproduced by heaping up strands binding glass fibers, each consisting of single yarns of 3-30mum in diameter, in almost un-orientated state and shaping in the form of a mat by needle punching, is prepared. Next, the glass fiber mat is impregnated with crystalline ethylene-propylene random copolymer, which is produced by compolymerizing propylene and ethylene. The especially favorable ethylene content in ethylene- propylene copolymer is 2-6wt.%. The content of the mat-like glass fiber is set to be 35-60wt.%. Thus, a molded item, which has simple composition and airtightness and high strength, can be obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a glass fiber reinforced composite for molding airtight products, and is particularly suitable for compression molding of products that require airtightness, such as sleeves for communication cable connections. The present invention relates to a glass fiber reinforced composite.

(Prior Art) A composite material in which matte long glass fibers are impregnated with a thermoplastic resin is used as a base plate for mechanical stamping presses, a so-called stampable sheet.

Stampable sheets of this type that use polypropylene resin as thermoplastic resin are being considered for use in various press-formed products due to their light weight, chemical resistance, impact resistance, and low cost. ing.

However, it is unclear whether such conventionally known polypropylene composite materials have sufficient mechanical strength and impact resistance.
When a press-molded product is used in a sealed state from the outside, such as in a sleeve for a communication cable connection, there is a problem with airtightness.

For this reason, when obtaining molded products that require performance such as gas sealing or moisture proofing, the base plate is matte glass fiber with 10 to 20% by weight of talc or mica.
(JP-A No. 61-1.8501.9), impregnated with polypropylene resin containing modified polypropylene (JP-A No. 62-68823), or during molding, a metal plate or a Method of pasting non-breathable materials such as metal foil (Japanese Patent Application Laid-Open No. 61-86245
) have been proposed, but all of these original plates or methods have the technical problems described below.

(Problem to be solved by the invention) In other words, although the airtightness is satisfied with the first original plate, the content of glass fiber is about 25% by weight due to the addition of about 15% by weight of talc or mica. hand,
It has a disadvantage of lower bending strength and tensile strength than ordinary stampable sheets with a glass fiber weight content of 40%, and is unsatisfactory in terms of strength as a connecting sleeve for cables buried directly in the soil. be. On the other hand, with the second original plate using modified polypropylene, if the molten modified polypropylene resin adheres to the impregnating and pressing device made of metal during the manufacturing process of the original plate, the original plate will adhere to the impregnating and pressing device, causing operational problems. The third method of attaching a metal plate or metal foil during molding requires lamination of an adhesive layer to the metal plate or metal foil or pre-compression molding prior to compression molding. Therefore, there are problems such as an increase in the number of steps or the need to place the surface metal plate in a fixed position during molding, requiring a peripheral clamping device, which complicates the manufacturing process.

The present invention has been made in view of the above-mentioned problems, and includes:
The purpose is to provide a glass fiber-reinforced composite that has a simpler composition than known glass fiber-reinforced composites and can provide molded products with airtightness and high strength.

(Structure of the Invention) The structure of the present invention for achieving the above object 1 is that in a glass fiber-reinforced composite made of glass fibers and synthetic resin, mat-like glass fibers constitute 35 to 60% by weight of the total weight. It is characterized in that it is impregnated with a resin whose main component is a crystalline ethylene-propylene random copolymer having an ethylene content of 2 to 6% by weight.

To explain in more detail, the mat-like glass fibers that can be used in the present invention are formed by needle-punching strands of glass fibers with a single diameter of 3 to 3 CJm, which are assembled in a substantially non-oriented manner. It is a thing,
It may be a glass fiber mat in which glass fiber rovings are arranged in parallel and arranged on the strands and punched in order to give directionality to the glass fibers if necessary.

The crystalline ethylene-propylene random copolymer to be impregnated into the glass fiber mat is a copolymer of propylene and ethylene, and in the present invention, the ethylene content in the ethylene-propylene random copolymer is 2 to 6% by weight. Those within the range are preferably used.

If the ethylene content is less than 2% by weight, the airtightness of the molded product cannot be ensured, and if it exceeds 6% by weight, the physical properties and heat distortion temperature will decrease.

In addition, the content of the above-mentioned matte glass fiber is 35 to 60
If it is less than 35% by weight, the physical properties such as bending strength will be insufficient, and if it is more than 60% by weight, glass fibers will protrude on the surface of the molded product, resulting in surface defects or poor airtightness. becomes.

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

・Example 1 A mat made by layering J lath fiber strands with a single yarn diameter of about 23) nn in a spiral shape was needle-punched at a rate of about 25 times per c♂. A crystalline ethylene-propylene random copolymer (manufactured by Ube Industries, Ltd.: RF-355) with 4% by weight is supplied in a molten state from a melt extruder, and the same pre-formed crystalline ethylene-propylene copolymer is supplied above and below the glass fiber mat. Approximately 0.5mm thick using propylene random copolymer
The fiberglass pine is supplied as an overlay and heated under pressure on a pair of upper and lower steel conveyors.・After impregnating the resin, it is subsequently cooled and solidified to obtain a glass fiber content of 40% by weight and an eyelid I'44.
A glass fiber-reinforced composite original plate having a weight of 00'g/I and a thickness of 3.7 mm was obtained.

The original plate of this Nojlas Fiber Navy 1 reinforced composite is 200X200
A blank cut into 1/2 mm size was heated until the internal resin temperature reached 200°C, and then heated for 3
The sheets were piled up, fed to a compression molding machine, and pressure molded at a mold clamping force of 12 tons, a mold cooling time of 60 seconds, and a mold temperature of 80'C, resulting in a length of 380 nu++ and an outer diameter of 130 mm.

A semi-cylindrical container with a wall thickness of 6 mm and flanges with a width of 20++o11 and a thickness of 10 mm was formed on both sides.

The airtightness of the obtained semi-cylindrical container was confirmed by the following method.

Two of the above-mentioned semi-cylindrical containers were prepared, their flanges were butted against each other with rubber gaskets interposed therebetween, and the containers were pressed at multiple locations with clamps to assemble into a sealed container.

15 kg/kg from the waste supply port previously set up inside.
This was immersed in a water tank while applying air pressure of c♂, and the presence or absence of leakage of the pressurized air inside was determined by visually inspecting the presence or absence of air bubbles on the surface of the semi-cylindrical container. During the 24-hour test, no air bubbles were observed. Also, while assembled, heat from -300C to 80oC.
After performing the heat cycle 10 times, a test was conducted under the same conditions as above, but as above, no air bubbles were observed.

On the other hand, the physical properties of the molded products were measured by the following methods. Tensile strength ASTM D638, bending strength ASTM D7
9o1 Izot impact strength ASTM D256, heat distortion temperature RA STMD 648 (load 18.6kg
) The measurement results obtained by these methods are summarized in Table 1.

Comparative Example 1 Using the same glass fiber mat as the glass mat in Example 1, using a homopolymer of polypropylene resin as the overlay and melt thermoplastic resin,
Example] A glass fiber reinforced composite (manufactured by the applicant: Azdel P11378K) was obtained in the same manner as in [Example]-, and this was compression molded to obtain a semi-cylindrical container.

When this semi-cylindrical container was tested for airtightness in the same manner as in Example 1, it was found that the container was unsuitable for molded products requiring airtightness due to the presence of air bubbles on the surface of the container.

・Comparative example 2 No J lath fiber mat with a basis weight of 540 g/d was used.
The overlay sheet resin used was the same crystalline ethylene-propylene random copolymer (A) as in Example 1 with 20% by weight of talc added, and the melt resin was prepared using the above (A) and h-tal. Crystalline ethylene-propylene random polymerized post-ethylene-propylene block copolymer with an ethylene content of 5.5% by weight (
B) 0.5 parts each of γ-methacryloxypropyltrimethoxysilane and t-butylperoxybenzoate per 100 parts by weight of the block copolymer10
．． Modified polypropylene (C) obtained by adding 25 parts and heat-treating at 220°C and talc (D) were mixed into A:C:D=2:
The glass content is 25% by using the mixture kneaded in 2.1.
An original plate of a fiber-reinforced composite of % by weight was prepared, and compression molding was performed in the same manner as in Example 1 using this original plate. As shown in Table 1, the molded product of this comparative example had excellent airtightness, but was poor in bending strength, tensile strength, and Izod impact strength.

In addition, in this comparative example, during the manufacturing process of the original plate, there was a problem in which the modified polypropylene of the melt protruded from the edge of the original plate and landed on the conveyor.

Normally, in a molded product having a rib shape, about half of the height (depth) of the rib is not filled with glass fibers, and the tip becomes resin-rich, causing a problem of cracking.

Therefore, using each original plate of Example 1 and Comparative Example 1,
Thickness: 3n+m, Width: 150++++11. length 200
A test piece with a rib having a +on+ flat plate part and a rib with a width of 4 mm and a height of 20 mm at the center of its - side was prepared, and this was placed in an atmosphere of -30'C with a tip radius of 2.5 m.
A falling ball impact test was conducted using a falling ball of 50 m.
When molded using the original plate of Comparative Example 1 with an energy of 0 kg-cm, cracks occurred at the tips of the ribs.

On the other hand, in the original plate of Example 1, no cracks were generated due to the impact of the falling ball.

In addition, the ribbed test piece above is -30'C to 80°C.
The heat cycle test of Example 1 was repeated 10 times.
No cracks were observed in the rib portions of the original plates used, confirming that they had sufficient cold resistance.

Table 1 (effects) It is not clear why the use of crystalline ethylene-propylene lander 1 copolymer with an ethylene content of 2 to 6% by weight improves airtightness, or when heated during compression molding. When the crystalline ethylene-propylene random copolymer is cooled and solidified in the mold after hot blank compression molding, the crystallization speed of the crystalline ethylene-propylene random copolymer is relatively slow, resulting in better adhesion between the glass fiber and the resin, making it better than conventional products. This seems to be because it prevents gas from leaking around the glass fibers.

In addition, the composite of the present invention has an increased content of long fiber glass fiber mat without adding inorganic fillers such as talc, so mechanical properties can be improved.
Since the resin has cold resistance and impact resistance, it is suitable for molded products having rib shapes.

The glass fiber reinforced composite for molding airtight products of the present invention is extremely useful for molding sleeves for communication cable connections, which require airtightness and high strength.

Claims (1)

[Claims] (1) In a glass fiber reinforced composite made of glass fiber and synthetic resin, a crystalline ethylene-propylene random copolymer with an ethylene content of 2 to 6% by weight is added to 35 to 60% by weight of the total weight of matted glass fibers. A glass fiber reinforced composite for molding airtight products, characterized by being impregnated with resin as the main component.