JP3447904B2 - Pole for blocking rod - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pole for a shutoff rod used for railroad crossings, roads, various gates, and the like, and more particularly to a pole for a shutoff rod that is small in displacement away from the base.

[0002]

2. Description of the Related Art Bamboo rods, wooden rods, metal pipes, etc. have been conventionally used as poles for barrier rods such as railroad crossings, roads, and various other gates, but recently they are light, have corrosion resistance and have appropriate strength. It is made of reinforced plastic.

For example, there is disclosed a railroad crossing blocking pole in which a laminated member having a reflection function composed of a metal foil and glass beads is laminated and fixed to a pole in which a pigment is mixed in a glass fiber reinforced resin at appropriate intervals ( Actual fair 3-4909
No. 4).

However, the glass fiber reinforced resin as described above does not always have sufficient adhesiveness between the glass fiber and the resin, for example, polyolefin, and the impact resistance is improved although the rigidity is improved by increasing the blending amount of the glass fiber. Is reduced. On the other hand, when the blending amount of glass fiber is reduced, the rigidity is lowered. In particular, with a long pole such as a pole for a shutoff rod, the downward displacement of the tip becomes large when the pole is horizontal, which makes it impractical. Further, although the specifications have not been determined in particular, many of the FRP cutoff poles on the market have a large displacement of 500 mm or more at the tip at a length of 6 m. Therefore, there has been a demand for a pole for a shutoff rod which has improved rigidity, improved displacement of the pole tip, and improved strength, durability and productivity.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pole for a shutoff rod which is improved in rigidity without impairing strength and durability and is improved so that displacement of a long pole tip becomes small. is there.

[0006]

As a result of intensive studies in view of the above problems, the present inventors have found that a specific glass fiber reinforced polypropylene composition is profile extrusion molded and has a rib in the longitudinal direction and a specific cross-sectional shape in the width direction. The present inventors have found that the pole can reduce the displacement of the tip of the pole without impairing the strength, and arrived at the present invention.

That is, the pole for the blocking rod of the present invention is
( 1 ) 79.9 to 30 wt% polypropylene having a melt flow rate of 1 to 50 g / 10 min, ( 2 ) 0.1 to 10 wt% modified polypropylene, and ( 3 ) 20 to 20 glass fibers.
A resin composition comprising 60 wt%, the ratio of the thickness of the pole is 1 to 10 mm, the maximum inner diameter of less and widthwise sectional outer diameter of 80 mm (a) and the minimum inside diameter (b) (b) /
(A) = 0.5~1 (however, (a) represents at most 78mm.) It is of.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Polypropylene which is a raw material of a resin composition for forming a pole for a blocking rod of the present invention includes homopolypropylene or propylene copolymer, preferably propylene-ethylene block copolymer. Among them, homopolypropylene is preferable from the viewpoint of rigidity. Also, the melt flow rate of polypropylene (230 ° C, load 2.16 kg, hereinafter referred to as MFR)
Is 1 to 50 g / 10 minutes, preferably 5 to 40 g / 10
Minutes. If the MFR is less than 1 g / 10 min, the extrusion moldability is insufficient, while if it exceeds 50 g / 10 min, the strength of the molded product decreases.

Another modified polypropylene used as a resin raw material is polypropylene, preferably homopolypropylene or highly crystalline homopolypropylene, and an unsaturated carboxylic acid or its derivative or a specific glycidyl compound having an acrylamide group and an epoxy group. Graft-polymerized.

Examples of the unsaturated carboxylic acid or its derivative include acrylic acid, maleic anhydride, hymic acid anhydride, glycyl methacrylate and the like. In addition, as a specific glydyl compound, "AXE" manufactured by Kanegafuchi Chemical Co., Ltd. and the like can be mentioned. Among these,
Maleic anhydride is preferred in terms of workability and economy.

The method for producing a modified polypropylene comprises the steps of modifying the polypropylene with the modifying compound and a radical generator,
For example, benzoyl peroxide, di-tert-butyl peroxide, tert-butyl peroxypiperate, 2,5
It is obtained by adding an organic peroxide such as dimethyl-2,5-ditertiary butyl peroxyhexyne and dicumyl peroxide, dry-blending in advance, and then heat-melting and kneading with an extruder or the like. The modified polypropylene obtained has an acid addition rate of preferably 0.1 to 10% by weight, more preferably 0.3 to 6% by weight, and an MFR of preferably 1 to 500 g / 10 minutes, more preferably 10
~ 200 g / 10 minutes.

Further, the glass fiber has an average fiber diameter of 6 to
11 μm (measured by electron microscope), average fiber length is about 3 mm
And chopped strands having a weight loss on heating of 0.2 to 8% by weight are preferable.

In the resin composition for forming the pole for the blocking rod of the present invention, the above ( 1 ) polypropylene is 30 to 79.9.
% By weight, preferably 52.5-74% by weight, 0.1-10% by weight of ( 2 ) modified polypropylene, preferably 0.1.
5 to 8% by weight and ( 3 ) glass fiber 20 to 60% by weight, preferably 25 to 40% by weight.

( 1 ) If the polypropylene content is less than 30% by weight, the moldability of the pole tends to deteriorate, while if it exceeds 79.9% by weight, the rigidity of the obtained pole decreases, and the tip of the long pole is largely displaced. If ( 2 ) the modified polypropylene is less than 0.1% by weight, the adhesion between the glass fiber and the polypropylene will be insufficient and the strength of the pole will be reduced. On the other hand, if it exceeds 10% by weight, there will be no improvement effect corresponding to the increase in the amount. Not economical. Further, (3) If the glass fiber content is less than 20% by weight, the rigidity of the pole is insufficient and the displacement of the pole tip becomes large, while if it exceeds 60% by weight, the strength such as impact resistance decreases. In addition, carbon black as a colorant, a pigment, and other additives such as a light stabilizer, a heat stabilizer, and an antioxidant may be added to the resin composition, if necessary.

The shape of the pole for the blocking rod of the present invention has the following cross-sectional shape and length shape in the width direction.

The cross-sectional shape in the width direction has reinforcing ribs continuous in the longitudinal direction on the inside or outside of the pole. The cross-sectional shape of the pole having the reinforcing rib in the width direction may be circular or elliptical as shown in FIGS. 2 (a) to 2 (f). Among these, displacement resistance and formability are preferable. 2 (a) is a cross section in which hollow ribs project above and below the circular pole from above, and FIG. 2 (b) is a cross section in which solid ribs project above and below the inside of the circular pole.

The wall thickness of the pole is 1 to 10 mm, preferably 2 to 5 mm. If the wall thickness is less than 1 mm, the strength is insufficient. On the other hand, if it exceeds 10 mm, the weight of the pole becomes large and the displacement of the tip of the pole becomes large, which is not economical. The outer diameter of the pole is 80 mm or less, preferably 30 to 60 mm. If the outer diameter of the pole exceeds 80 mm, the weight becomes large and the practicability such as operability is lacking. Further, the cross-sectional shape of the pole in the width direction is such that the ratio (b) / (a) of the maximum inner diameter (a) and the minimum inner diameter (b) of the pole is 0.5 to
1 is oval or circular. However, (a) is 78 mm
It is the following. If (b) / (a) is less than 0.5, the pole becomes an elliptical shape and is easily bent, which is not practical.

Next, regarding the length and shape of the pole, one having the same thickness from the fixed position to the tip and one having a plurality of pieces connected so that the thickness becomes thinner gradually toward the tip as shown in FIG. can give. In addition, the length of the pole is normally about 1.5 to 10 m in consideration of practicality, but when connecting the plurality of poles mentioned above, the length of one pole is 1
It is preferable that the poles having different thicknesses of ˜4 m are connected to each other so as to become thinner toward the tip and have a length of about 2 to 10 m. The connection of the poles may be, for example, fitted with the reinforcing ribs in the same direction as a fishing rod, but may be further fixed with an adhesive or mechanically.

Further, the pole having the above-mentioned cross-sectional shape is manufactured by dry-blending a glass fiber reinforced resin composition containing polypropylene, modified polypropylene and glass fiber in advance, and then extruding a deformed die having each cross-sectional shape. It can be obtained by supplying the mixture to a machine, melt-kneading, and extruding.

The above-mentioned pole for a blocking rod of the present invention is as follows:
It is composed of a composition containing polypropylene, modified polypropylene and glass fiber, and has the above-mentioned rib and cross-sectional shape. Therefore, the adhesiveness between polypropylene and glass fiber is excellent, so that it is lightweight and excellent in strength and rigidity. In particular, when the pole is horizontal from the fixed position, the displacement of the tip from the horizontal line can be 500 mm or less at the position of 6 m.

[0021]

The present invention will be described in detail with reference to the following specific examples. Examples 1 to 4, Comparative Example 1 MFR 20 g / 10 min homopolypropylene (hereinafter P
P), maleic anhydride modified polypropylene (acid addition rate 0.5% by weight, MFR 100 g / 10 minutes, hereinafter CMP)
And glass fibers (average fiber diameter 9 μm, average fiber length 3 m
m, loss on ignition of 0.5% by weight, hereinafter referred to as GF) in the proportions shown in Table 1, 0.3 parts by weight of carbon black was added to 100 parts by weight of this composition, and dry blending was performed in advance. It was followed, fed to the extruder with a profiled mold cross-section in FIG. 2 (b), as shown in Table 1 in the same cross-sectional shape by extrusion molding by melt kneading, the two having different diameters that can be spliced Got each pole of the seed.

Each of the obtained poles having a large diameter was cut to 3 m, leaving a fixed margin. Further, each pole having a small diameter was cut into 3 m, leaving a margin. Next, as shown in FIG. 1, each pole 2 having a large diameter is fixed to the fixing portion 1, and each pole 3 having a small diameter is inserted and fitted into the inner diameter of this pole so that the pole has a total length of 6 m and is horizontal. The displacement distance A of the tip shown in FIG. 1 at that time was evaluated and shown in Table 1.

[0023]

[Table 1] As is clear from Table 1, the resin composition used in the present invention has high rigidity. Therefore, the displacement of the 6 m tip of each pole is less than 500 mm. On the other hand, the pole of the comparative example has a lower rigidity than that of the present invention, and therefore, the displacement at the tip of 6 m is 1,070 mm, which is about twice as large as that of the present invention.

[0024]

The pole for the blocking rod of the present invention is made of PP, CM.
Since it is composed of P and GF and has the specific cross-sectional shape, it is lightweight and has excellent strength and rigidity. Therefore, the displacement of the tip of the pole is small. In addition, since the production can be performed by extrusion using a deformed die, the production efficiency is good.

[Brief description of drawings]

FIG. 1 is a schematic side view of a pole according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX in FIG.

[Explanation of symbols]

Fixed part of 1 pole 2 diameter thick pole 3 diameter thin pole 4 Reinforcing rib A Tip displacement distance

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Miyasaka Kenji Miyasaka 3-1, Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan Polychem Co., Ltd., Kawasaki Technical Center (56) Reference JP-A-7-300072 (JP, A) ) JP-A-10-100903 (JP, A) JP-A-10-44999 (JP, A) JP-A-5-278616 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B61L 29/04 E01F 13/00

Claims (3)

(57) [Claims] 1. A melt flow rate of 1 to 5
79.9-30% by weight of polypropylene, 0 g / 10 minutes,
( 2 ) Modified polypropylene containing 0.1 to 10 wt% and ( 3 ) glass fiber 20 to 60 wt%
A pole for a blocking rod made of, the thickness of the pole 1
-10 mm, outer diameter of 80 mm or less, and ratio (b) / (a) of maximum inner diameter (a) and minimum inner diameter (b) of cross section in width direction =
0.5 to 1 (however, (a) is 78 mm or less . ) A pole for a blocking rod. 2. The cross section in the width direction of the pole is (b) /
2. The pole for a blocking rod according to claim 1, wherein (a) = 1, and a hollow rib protruding upward and downward on the outside or a solid rib protruding upward and downward on the inside is provided. 3. The length of the pole for the blocking rod is 1 to 4 m.
3. The pole for a blocking rod according to claim 1 or 2, wherein at least two poles of 2 are connected to each other so that the thickness thereof becomes thinner toward the tip.