JPH04209657A - Blow molding composition - Google Patents

Abstract

PURPOSE:To prepare the title compsn. giving a blow molded article excellent in rigidity and quality by compounding a plastic material with a specified amt. of a fibrous material having specified sizes. CONSTITUTION:The title compsn. comprises a plastic material and 1-30wt.% (based on the plastic material) fibrous material having a diameter of 2--100mum and a length of 1-30mm. The fibrous material is not limited specifically, though glass fiber is esp. pref. The plastic material is also not limited specifically, examples being polyethylene, polypropylene, nylon, polyethylene terephthalate, ABS, polycarbonate, and polyphenylene oxide.

Description

[Detailed description of the invention]

[00011

[Industrial Field of Application] The present invention relates to a novel composition for blow molding, and more particularly to a composition for obtaining fiber-reinforced plastics. [0002] [Prior art] Fiber reinforced thermosetting plastic (FRP)
is a plastic material to a fiber material, such as glass fiber,
By mixing carbon fiber or Keplerian fiber, it adds rigidity and elasticity to the lightness of plastic. [0003]

[Problems to be Solved by the Invention] However, attempts to produce this type of reinforced plastic by blow molding have had little success. That is, in the case of blow molding, it is difficult to expand the parison even with short fibers;
In the case of such long fibers, it was extremely difficult to mold them even if the mixing ratio was 1% or less. Therefore, it has been almost impossible to improve the rigidity of blow-molded products by using the tensile strength of the fibers. Therefore, there has been a need for a method of manufacturing blow-molded products of high rigidity and excellent quality by incorporating long fibers. [0004]

[Means for Solving the Problems] The present inventors have discovered that when a plastic material contains an appropriate amount of fiber material of a certain size range and is molded by blow molding, the fiber material is oriented in a certain direction and has extremely high strength. The inventors have discovered that a plastic molded product with high corrosion resistance can be obtained, and have completed the present invention. That is, the present invention provides plastic materials with a diameter of 2μ to
100μ, length 1-30mm, preferably diameter 5μ-1
1 to 30% by weight of fiber material with a diameter of 5 μm and a length of 5 to 15 mm;
The present invention provides a blow molding composition containing preferably 5 to 10% by weight. [00051 The fibrous material that can be contained in the composition of the present invention is normally selected as appropriate from the types used in the production of reinforced plastics. Such fiber materials include glass fibers, carbon fibers and Kepler fibers. After mixing an appropriate amount of the fiber material in the above size range with the plastic material for blow molding and stirring if desired,
When a parison is formed and molded with a mold, a plastic molded article is obtained in which fiber material oriented in a certain direction is evenly distributed. The molded product thus obtained has excellent rigidity and can be used for various purposes. [00061 Although the present invention is not limited to particular fiber materials, glass fibers are particularly preferred. The base plastic material is appropriately selected from those used for blow molding, and includes, but is not limited to, polyethylene, polypropylene, nylon, polyethylene terephthalate, ABS, polycarbonate, and polyphenylene oxide. [0007] Equipment and molding conditions for blow molding are known to those skilled in the art, and the compositions of the present invention are applicable to any equipment and method. However, high-pressure pouring using a rapid compression die that applies pressure to the tip of the die is preferred because the fibers are sufficiently oriented within the plastic material. Usually 50-150 kgf/cm2
apply pressure. In addition, to improve the orientation of the fibers, pinch the lower part of the parison with a suitable device and pull it for about 14 minutes.
It is desirable to stretch it 1 to 1.3 times. However, even if the parison is stretched by its own weight, the orientation is good. [0008]

[Action] The composition of the present invention has a diameter of 2 liters to 100 μ,
Since it contains an appropriate amount of long fiber material with a length of 1 to 30 m, when it is subjected to blow molding, the fibers are uniformly distributed and oriented in a certain direction (vertical direction). Therefore, the parison does not easily expand in the lateral direction and prevent molding, and because the fibers are highly oriented, extremely rigid plastic molded products can be obtained. The flexural modulus of molded products obtained using the composition of the present invention containing glass fibers is higher than that of molded products obtained using conventional short glass fibers, and the strain under bending load of the molded product is reduced by about 2/3. It can be suppressed to ~3/4. [0009] In addition, in the case of pipes, the conventional
When 15% of glass fibers with a short length of m are mixed, if the original parison diameter becomes less than 1/3 of the pipe diameter, the parison has poor elongation and blow molding is difficult, but according to the present invention,
Since the glass fibers are well oriented in the longitudinal direction, pipes of arbitrary shapes can be manufactured without such problems. [00101 Examples] In the examples, measurements of the flexural modulus of molded articles were made according to plastic material testing methods known to those skilled in the art. [00111 That is, a test piece with a thickness of 2.4 mm, a width of 25 mm, and a length of 100 mm was prepared, and both ends were connected with a span of 80 m.
m supporting point, and the center of the test piece was moved at a speed of 4.1 mm.
The flexural modulus of elasticity is calculated according to the following formula by pressing with a "wedge" that descends at a rate of /mm. EB (kg/cm2) = L'' m/4bc13 In the above formula, each abbreviation has the following meaning. EB: Bending modulus of elasticity, L: Distance between fulcrums (cm), b
: Width of test piece (cm), d : Length of test piece (c
m), m: Inclination of initial straight section (kg/cm) [0012] Example 1 Bumper reinforcement (
Automotive bumper beam) 1) Based on polypropylene with a weight ratio of 6% and a length of 3~
Glass fibers of 8 mm were mixed in, and the pajason was extruded to a length of 120 cm at a pressure of 100 kgf/cm2 using a rapid compression die that applied pressure to the tip of the die. After stretching the lower part of the parison between pre-pinch plates and stretching it to about 1.3 times, the mold was tightened and blow molding was performed into a bumper reinforcement while blowing air into the parison. 2) A bumper reinforcement was blow molded under similar conditions, but the lower part of the parison was stretched by its own weight without being pulled. 3) For comparison, a short glass fiber (approximately Q, 5mm
) under the same conditions. Table 1 shows the flexural modulus of the molded product thus obtained. [0013] Table-1 Molded product ``l-m=91-----Each piece has the same longitudinal force.
Approximately 30,000 Approximately 24,000 1h15,00
0 Same as in the horizontal direction Approximately 14,000 Approximately 15,000 Approximately 14,000 Unit: kgf/cm" Longitudinal direction - direction parallel to the molding direction Lateral direction: direction perpendicular to the molding direction [00141 Bumper rain obtained in Example 1 When the hosement is attached to a car and a load is applied to the entire surface, compared to a product mixed with normal 0.5mm glass fiber,
The resulting distortion was about 2/3 to 3/4. [0015] Example 2 Glass fibers with a length of 3 to 10 mm are mixed at a weight ratio of 15% based on all-braided polypropylene, and 100 parisons are formed at a pressure of 150 kgf/cm2 using a rapid compression die that applies pressure to the tip of the die.
cm extruded. Next, the mold was tightened, and the parison was blow-molded into an all-blade shape while blowing air into the parison. The direction of the mold was set so that the upper part was the blade part and the lower part was the pipe part, so the bending elastic modulus of the upper part, where the parison was stretched a lot, was 45,000 kgf/cm2 vertically and 20,00 kgf/cm2 horizontally.
00kgf/cm”, the bending elastic modulus of the lower pipe section is
Vertical 40,000kgf/cm2 and horizontal 23,000k
gf/cm2. [00161 In the case of the all-blade of this example, the weight required to leak a product having the same stiffness as a product mixed with normal 0.5 mm glass fibers was reduced by about 2/3. [0017] [Effect 1] According to the present invention, a plastic product with excellent rigidity can be easily manufactured. Further, according to the present invention, weight reduction can be achieved without reducing the strength of the product, and furthermore, it has become easier to manufacture reinforced pipes, which was difficult in the past.

Claims (4)

[Claims] Claim 1: For plastic material, diameter 2μ to 1
A blow molding composition containing 1 to 30% by weight of a fiber material having a diameter of 00μ and a length of 1 to 30 mm. Claim 2: The fiber material has a diameter of 5 μm to 15 μm and a length of 5 μm to 1 μm.
The composition of claim 1, which is 5 mm. 3. The composition according to claim 1 or 2, wherein the fiber material is glass fiber. 4. The blow molding plastic material is selected from polyethylene, polypropylene, nylon, polyethylene terephthalate, ABS, polycarbonate and polyphenylene oxide.
3. The composition of any one of 3.