JP2005061047A - Form for placing concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recyclable plastic form for placing concrete, excellent in both bending rigidity and impact resistance and lightweight, good in workability, releasability of concrete, and durability. <P>SOLUTION: The form for placing concrete is composed of a propylene-ethylene block copolymer having 0.3-4.0 g/10 min in melt mass flow rate (MFR), a resin compound including a powdery and granular inorganic filler within 1-20 μm in average particle size. The mass ratio ( propylene-ethylene block copolymer/inorganic filler ) of propylene-ethylene block copolymer to the inorganic filler ranges 60/40-95/5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a concrete casting mold made of plastic.

Conventionally, a concrete placement form (hereinafter referred to as “concrete formwork” or simply “formwork”) is made of veneer plywood or the like because it is inexpensive and easy to process such as nailing. A plywood formwork is used in which piers are nailed on the back of the dam plate.
However, such a plywood formwork (i) requires a nailing operation for fixing the pier and joining the formwork, and is poor in workability. (Ii) It is applied to the surface of the nail and the dam plate. Due to the concrete stripping agent, the formwork is fragile and the number of diversions is small (for example, about 5 times). (Iii) If the diversion number is exceeded, it cannot be recycled as wood and must be disassembled and incinerated. , And so on.

As a solution to these problems, a glass fiber reinforced plastic mold that is lightweight, has good workability, does not require a concrete release agent, and has high durability is disclosed in, for example, Japanese Patent Laid-Open No. 2-8459 (Patent Document 1). Has been proposed.
However, this plastic mold has a problem that the glass fiber protrudes from the cut surface or the like, and touching that part causes irritation (tackiness) on the skin, making it difficult to handle. Further, when the glass fiber protrudes from the concrete casting surface, the concrete casting surface becomes rough and the peelability of the concrete deteriorates.

As other plastic molds, corner molds obtained by extruding a resin composition comprising a polyolefin-based resin and an inorganic filler, specifically, homopolypropylene, glass fiber, talc or calcium carbonate was blended as an inorganic filler. A thing is proposed by Unexamined-Japanese-Patent No. 6-294208 (patent document 2).
This plastic mold uses homopolypropylene having excellent bending rigidity (bending elastic modulus) required for the mold, and further contains various inorganic fillers in order to increase bending rigidity. However, homopolypropylene has the worst impact resistance among polypropylenes, and further contains an inorganic filler that lowers the impact resistance, so the resulting plastic mold has a problem with impact resistance. . In concrete placement sites, the formwork is often handled messy, and impact resistance is required. However, if the formwork made of homopolypropylene is thrown away or if the formwork is struck violently, the corners will be sharp. Sometimes chipped or cracked. This problem is particularly likely to occur in cold regions.

In addition, the formwork is often stored outdoors in a wild state. However, polypropylene resin has poor light resistance (weather resistance), and the formwork made of this has a problem that when stored outdoors for a long period of time, bending rigidity and impact resistance are lowered, and the number of diversions is reduced. It was.
Moreover, as a general problem of the formwork, the concrete placement site surrounded by the formwork is dark and the feet are dangerous, so there is a problem that lighting is necessary even in the daytime.
JP-A-2-8459 (page 2-4) JP-A-6-294208 (page 2-4)

Therefore, the object of the present invention is to provide a plastic concrete casting form made of plastic that is excellent in both bending rigidity and impact resistance, is lightweight, has good workability, has good peelability, has high durability, and is recyclable. Is to provide.
Another object of the present invention is to provide a concrete casting mold made of plastic having high light resistance (weather resistance).
Another object of the present invention is to provide a concrete casting form made of plastic with high translucency.

  That is, the concrete casting mold according to the present invention includes a propylene-ethylene block copolymer having a melt mass flow rate (MFR) of 0.3 to 4.0 g / 10 min and an average particle size of 1 μm to 20 μm. It consists of a resin composition containing a certain granular inorganic filler, and the mass ratio of propylene-ethylene block copolymer to inorganic filler (propylene-ethylene block copolymer / inorganic filler) is 60/40 to 95 / It is characterized by being 5.

The resin composition is 0.01 to 2.0 parts by mass of a hindered amine light stabilizer, and 0.01 to 2 with respect to 100 parts by mass in total of the propylene-ethylene block copolymer and the inorganic filler. It is desirable to contain 0.0 part by mass of an ultraviolet absorber.
The inorganic filler is preferably talc.
The average particle size of the inorganic filler is desirably 3 μm to 20 μm.

Also, the concrete placement form of the present invention includes a dam plate portion where one side becomes a concrete placement surface, and a side plate bent at right angles from both side edges of the dam plate portion to the opposite side of the concrete placement surface of the dam plate portion. It is desirable to have a part.
Further, in this concrete casting form, at least one side plate portion is provided with two protruding ridges extending in the vertical direction on the outer surface, and one side surface of the one ridge portion is a dam plate portion. It is desirable to be flush with the concrete placement surface.
Moreover, it is desirable that the dam plate portion and the side plate portion be a hollow panel in which two plates and a plurality of long reinforcing ribs connecting the plates and extending in the vertical direction are integrally formed.
Further, it is desirable that a reinforcing plate portion parallel to the side plate portion is provided on the back surface of the concrete placing surface of the dam plate portion.

  The concrete casting mold of the present invention comprises a propylene-ethylene block copolymer having a melt mass flow rate (MFR) of 0.3 to 4.0 g / 10 min, and a powder having an average particle size in the range of 1 to 20 μm. It consists of a resin composition containing a granular inorganic filler, and the mass ratio of propylene-ethylene block copolymer to inorganic filler (propylene-ethylene block copolymer / inorganic filler) is 60/40 to 95/5. Therefore, it is excellent in both bending rigidity and impact resistance, is lightweight, has good workability, has good peelability of concrete, has high durability, and is recyclable. In addition, the machinability is equivalent to that of a conventional plywood formwork.

The resin composition is 0.01 to 2.0 parts by mass of a hindered amine light stabilizer, and 0.01 to 2 with respect to 100 parts by mass in total of the propylene-ethylene block copolymer and the inorganic filler. If it contains 0.0 part by mass of an ultraviolet absorber, the light resistance (weather resistance) of the mold is greatly improved.
Further, if the average particle size of the inorganic filler is 3 μm to 20 μm, the translucency is improved without lowering the bending rigidity, impact resistance, and cutting workability of the mold, and the periphery is surrounded by the mold. It is possible to incorporate external lights into the concrete placement site.

The present invention will be described in detail below.
The resin composition which is a material for the concrete casting mold of the present invention contains a propylene-ethylene block copolymer and a powdered inorganic filler.
A propylene-ethylene block copolymer is obtained by copolymerizing elastomeric ethylene and propylene after polymerization of propylene or simultaneously with polymerization of propylene, and includes a crystal part (homopolypropylene) and an amorphous part. It is a mixture of (ethylene-propylene copolymer rubber). The propylene-ethylene block copolymer has the highest impact resistance among polypropylenes, and the rigidity is also high after homopolypropylene.

  As the propylene-ethylene block copolymer, those having a melt mass flow rate (MFR) in the range of 0.3 to 4.0 g / 10 min are used. When the melt mass flow rate (MFR) is less than 0.3 g / 10 min, the fluidity at the time of extrusion molding is lowered and the moldability is deteriorated. When the melt mass flow rate (MFR) exceeds 4.0 g / 10 min, the drawdown is reduced. It becomes large and the extrusion moldability deteriorates. Here, the melt mass flow rate (MFR) is a value measured under conditions of a temperature of 230 ° C. and a load value of 2.16 kg in accordance with JIS K6921-2.

  The ethylene content of the propylene-ethylene block copolymer is preferably 1.5 to 20% by mass. If the ethylene content is less than 1.5% by mass, the impact resistance of the mold may be insufficient. If the ethylene content exceeds 20% by mass, the bending rigidity of the mold may be insufficient. is there.

  The inorganic filler in the present invention is a granular material excluding a fibrous material such as glass fiber. Examples of such inorganic fillers include talc, calcium carbonate, mica, and clay. Of these, talc, which has a high effect of improving bending rigidity, is preferably used.

  As the inorganic filler, those having an average particle diameter in the range of 1 μm to 20 μm are used. When the average particle size is less than 1 μm, a large shearing force is required to disperse the inorganic filler in the resin composition, and the resin composition has a high viscosity and fluidity during extrusion molding is reduced. On the other hand, when the average particle size exceeds 20 μm, the impact resistance of the mold becomes insufficient.

When considering the translucency of the formwork, the hiding power by the inorganic filler is important. The hiding power increases as the difference between the refractive index of the inorganic filler and the refractive index of the propylene-ethylene block copolymer serving as the base increases. Inorganic fillers having a high refractive index are not preferred, and talc, calcium carbonate, and mica having a low refractive index are preferably used.
Moreover, the hiding power by the inorganic filler increases as the inorganic filler particles become smaller, and the particle size of the inorganic filler becomes maximum at a half wavelength of visible light (0.2 to 0.4 μm). Therefore, when translucency is required for the mold, the average particle diameter of the inorganic filler is preferably in the range of 3 μm to 20 μm, and more preferably 5 μm to 20 μm.

  The amount of the inorganic filler in the resin composition affects the bending rigidity, impact resistance, translucency and cutting workability of the mold. If the amount of the inorganic filler is kept low, the impact resistance and translucency of the mold will be improved, but the bending rigidity will be insufficient. Also, if the amount of inorganic filler is small, the base propylene-ethylene block copolymer dissolves when the mold is cut with a rotating blade rotating at high speed or when a hole is made in the mold with a drill or the like. , Burrs and the like are likely to occur.

  Therefore, the mass ratio of the propylene-ethylene block copolymer to the inorganic filler (propylene-ethylene block copolymer / inorganic filler) in the resin composition is in the range of 60/40 to 95/5, that is, the propylene-ethylene block. In a total of 100% by mass of the copolymer and the inorganic filler, the propylene-ethylene block copolymer is 60 to 95% by mass, and the inorganic filler is 5 to 40% by mass. When the mass ratio is less than 60/40, the amount of inorganic filler is excessive, and the impact resistance and translucency of the mold are insufficient. On the other hand, when the mass ratio exceeds 95/5, the amount of the propylene-ethylene block copolymer increases, and sufficient bending rigidity as a mold cannot be obtained, and the machinability of the mold deteriorates. It becomes difficult to process a formwork with the same feeling as a conventional plywood.

It is preferable that a hindered amine light stabilizer (HALS) and an ultraviolet absorber are blended in the resin composition.
Examples of hindered amine light stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sepacate, succinic acid and N- (2-hydroxypropyl) -2,2,6,6-tetra. Condensate with methyl-4-hydroxypiperidine, tetrakis (2,2,6,6-tetramethyl-4-piperidyl), 1,2,3,4-butanetetracarboxylate, N, N′-bis (2 , 2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine and 1,2-dibromoethane, bis (2,2,6,6-tetramethylpiperidyl) adipate, bis (2, 2,6,6-tetramethylpiperidyl) fumarate, poly [[6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [(2, 2 , 6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino]] and the like.

  The blending amount of the hindered amine light stabilizer is preferably in the range of 0.01 to 2.0 parts by mass with respect to 100 parts by mass in total of the propylene-ethylene block copolymer and the inorganic filler. If the blending amount is less than 0.01 parts by mass, the light resistance (weather resistance) of the mold may be insufficient. On the other hand, even if the amount exceeds 2.0 parts by mass, the effect of improving the light resistance cannot be expected for the amount added, which is not economical.

  Examples of the ultraviolet absorber include salicylic acid derivatives, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and benzoate-based ultraviolet absorbers. In these, a benzotriazole type ultraviolet absorber and a benzoate type ultraviolet absorber are preferable. Examples of the benzotriazole ultraviolet absorber include 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole and 2- (3,5-di-t-butyl-2. -Hydroxyphenyl) -5-chlorobenzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- ( 2-hydroxy-5-t-octylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole and the like. Examples of benzoate ultraviolet absorbers include 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-t-butyl-4- Examples thereof include hydroxybenzoate.

  The blending amount of the ultraviolet absorber is preferably in the range of 0.01 to 2.0 parts by mass with respect to 100 parts by mass in total of the propylene-ethylene block copolymer and the inorganic filler. If the blending amount is less than 0.01 parts by mass, the light resistance (weather resistance) of the mold may be insufficient. On the other hand, even if the amount exceeds 2.0 parts by mass, the effect of improving the light resistance cannot be expected for the amount added, which is not economical.

Various additives such as an antioxidant, a lubricant and a colorant may be added to the resin composition as long as the object of the present invention is not impaired.
The resin composition in the present invention is prepared by blending a propylene-ethylene block copolymer, an inorganic filler, a hindered amine light stabilizer, an ultraviolet absorber, and various additives as necessary, and kneading these with an extruder or the like. Can be prepared.

The concrete casting mold of the present invention can be molded by, for example, extruding from a mold of the resin composition. In the case of extrusion molding, the length (height) of the mold can be freely set, and it is possible to produce a long mold that does not exist in the conventional plywood mold.
Although the shape of the concrete placement form of the present invention is not particularly limited, for example, a form as shown in FIG. 1 can be exemplified.

  1 and 2 are views showing an example of a concrete casting form according to the present invention. This mold 30 has a hollow dam plate portion 32 whose one surface becomes a concrete placement surface 31, and a hollow bent at right angles from both side edges of the dam plate portion 32 to the opposite side of the concrete placement surface 31 of the dam plate portion 32. Provided on the rear plate 34 of the side plate portion 33, two hollow projecting ridge portions 41, 42 extending in the vertical direction protruding from both side edges of the outer surface 38 of the side plate portion 33, and the dam plate portion 32, It has a general configuration including four hollow reinforcing plate portions 35 parallel to the side plate portion 33.

Here, one side surface of the ridge 41 on the concrete placement surface 31 side is flush with the concrete placement surface 31 of the dam plate portion 32.
In addition, an inclined surface 43 is formed on the side surface of the ridge 42 that faces the ridge 41.

As shown in FIG. 3, the inclined surfaces 43 are arranged in a row so that the plurality of molds 30 are in contact with each other between the protruding ridges 41 protruding from the outer surface 38 of the side plate portion 33 and the protruding ridges 42. At this time, the inclined surfaces 43 of the projecting ridge portions 42 that contact each other face each other to form a groove 44 having a V-shaped cross section.
The groove 44 formed in this manner is used when a drill 51 is used to form a through hole for inserting a separator in a contact portion between the protruding strips 42 when the below-described formwork 30 is installed (built). It serves as a guide groove at the drill tip.

  When the inclined surface 43 is not formed on the ridge 42, the guide groove at the tip of the drill is not formed. Therefore, even if an attempt is made to drill the insertion hole for inserting the separator in the contact portion between the ridges 42 with the drill 45. The tip of the drill is shifted to the left and right from the abutting portion between the ridge portions 42, and the insertion hole for inserting the separator cannot be drilled perpendicularly to the dam plate 32, so that the insertion hole can be drilled. Prone to failure.

  The side plate portion 33 and the reinforcing plate portion 35 are formed of a hollow panel in which two parallel plates 36 and 36 and a plurality of long reinforcing ribs 37 connecting the plates are integrally formed. .

  The dam plate portion 32 is a hollow panel formed by integrally forming two parallel plates 36 and 36 and a plurality of long reinforcing ribs extending between the plates and extending in the vertical direction. The reinforcing ribs of the two plates that form the side plate portion 33 and the reinforcing plate portion 35 at a right angle to the concrete placing surface 31 at the portion where the side plate portion 33 and the reinforcing plate portion 35 are in contact with the dam plate portion 32. The right-angled ribs 46 are formed continuously from 36, and the other portions are inclined ribs 47 that are inclined with respect to the concrete placement surface 31 and formed continuously in a zigzag manner.

The dimensions, such as the thickness, width, and height, of the dam plate portion 32, the side plate portion 33, and the reinforcing plate portion 35 are not particularly limited, and are set to be approximately the same as the dimensions of a conventional plywood formwork, for example.
Further, the thicknesses of the two plates 36, the reinforcing rib 37, the right-angle rib 46, and the inclined rib 47 constituting the dam plate portion 32, the side plate portion 33, and the reinforcing plate portion 35 are not particularly limited, but are translucent and lightweight. For example, 1 to 3 mm is appropriate.

The height of the ridges 41 and 42 is formed in the contact portion of the ridge when overlapped with the ridges 41 and 42 of another mold 30 installed adjacent to the mold 30. It is set as appropriate according to the outer diameter of the separator inserted through the insertion hole. For example, when the outer diameter of the separator is a normal 8 mm, the height of the ridges 41 and 42 is about 7 mm.
Moreover, the width | variety of the protruding item | line parts 41 and 42 should just be made narrower than the width | variety of the side-plate part 33, and is not specifically limited.

Next, the installation (building) of the concrete placement form of the present invention will be described with reference to FIGS.
First, the plurality of molds 30 are arranged in a row so that the outer surfaces 38 of the side plate portions 33 are in contact with each other. Adjacent side plate portions 33 are temporarily fixed using a clip fitting (not shown) having a U-shaped cross section, and as shown in FIG. An insertion hole for inserting a separator is drilled in the portion with a drill 51. A round bar-shaped separator 22 provided with a P-con 21 is inserted into the insertion hole. Next, a fastening fitting 23 (Form Tie (registered trademark)) is attached to the end of the separator 22 protruding from the insertion hole by screwing, and the P-con 21 of the separator 22 and the counter plate 24 at the proximal end of the fastening fitting 23. The width direction of the side plate portion 33 is sandwiched between the two.

  Similarly, the plurality of molds 30 are arranged in a row so that the concrete placement surfaces 31 face each other. At this time, a through hole for inserting a separator is formed in a contact portion between the protrusions 41 and a contact portion between the protrusions 42, and the separator 22 is inserted through the insertion hole. Next, a fastening fitting 23 is screwed onto the end of the separator 22 protruding from the insertion hole, and the side plate 33 is placed between the P-con 21 of the separator 22 and the counter plate 24 at the base end of the fastening fitting 23. The mold 30 is held so as to sandwich the width direction.

  Further, a pair of flat members 25 made of square pipes are arranged above and below the fastening bracket 23, and a washer 26 that supports them and a wedge 27 that stops the washer 26, and the horizontal member 25 is reinforced with the side plate portion 33 and the reinforcement. It fixes in the state contact | abutted to the side surface of the board part 35. FIG. By disposing the laterally flat member 25, the mold frame 30 is prevented from expanding outward due to the pressure of the concrete when placing the concrete.

  In the mold 30 as described above, a propylene-ethylene block copolymer having a melt mass flow rate (MFR) of 0.3 to 4.0 g / 10 min, and an average particle size in the range of 1 μm to 20 μm. It consists of a resin composition containing a certain granular inorganic filler, and the mass ratio of propylene-ethylene block copolymer to inorganic filler (propylene-ethylene block copolymer / inorganic filler) is 60/40 to 95 / Therefore, both the bending rigidity and the impact resistance are excellent, and the machinability is equal to that of the conventional plywood formwork.

The resin composition is 0.01 to 2.0 parts by mass of a hindered amine light stabilizer, and 0.01 to 2 parts by mass with respect to 100 parts by mass in total of the propylene-ethylene block copolymer and the inorganic filler. If 0 part by mass of the ultraviolet absorber is contained, the light resistance (weather resistance) of the mold is greatly improved.
Further, if the average particle size of the inorganic filler is 3 μm to 20 μm, the translucency is improved without lowering the bending rigidity, impact resistance and cutting workability of the mold, and the periphery is surrounded by the mold. It is possible to incorporate external lights sufficiently at the concrete placement site.

Further, since the mold 30 is a plastic concrete casting mold, the mold 30 has good durability and can be recycled as a plastic material after exceeding the number of times of use. Moreover, since the mold 30 is made of plastic, it has good concrete releasability and does not require a concrete release agent.
Further, the mold 30 is made of plastic and has a dam plate portion 32 whose one surface becomes the concrete placement surface 31 and a right angle from both side edges of the dam plate portion 32 to the opposite side of the concrete placement surface 31 of the dam plate portion 32. Therefore, the nailing for fixing the pier is unnecessary, the workability is good, and the durability is not lowered by the nailing. Such a mold 30 has a significantly longer service life than a conventional plywood mold.

Further, in such a mold 30, since the two protruding ridges 41, 42 extending in the vertical direction are projected on the outer surface 38 of the side plate portion 33, when installing the mold 30, An insertion hole for the separator can be formed in the contact portion between the protrusions 41 of the mold 30 and the contact portion between the protrusions 42, and the insertion hole needs to be formed in the barrier plate 32. Absent.
In addition, such a mold 30 receives the clamping pressure by the P-con 21 of the separator 22 and the counter plate 24 at the base end of the clamping bracket 23 in the width direction of the side plate 33, Sufficient strength. Therefore, when the metal fittings for formwork that tends to concentrate pressure on one point such as P-con 21 and fastening metal fittings 23 (form tie (registered trademark)) used for the plywood molds made of conventional veneer plywood, etc. However, the mold 30 is not damaged.

Moreover, in this formwork 30, since the two protruding item | line parts 41 and 42 extended in a perpendicular direction are protrudingly provided in the outer surface 38 of the side-plate part 33, when the formwork 30 is installed, it adjoins. A space 50 surrounded by the side plate portion 33 and the ridge portions 41 and 42 is formed between the mold frames 30 and 30. This space 50 can play a role of collecting concrete leaking from the contact portion between the adjacent protruding strips 41 on the concrete placing surface 31 side, and the concrete does not leak outward from the mold 30.
Moreover, since this mold 30 is the same plane as the concrete placement surface 31 of the dam plate part 32, the one side surface of one convex part 41 is made into the same plane among the two convex parts. It is possible to keep the concrete surface flat without causing the concrete surface placed later to become uneven at the joints of the mold 30.

Moreover, since this formwork 30 is provided with a reinforcing plate portion 35 parallel to the side plate portion 33 on the back surface 34 of the concrete placing surface 31 of the dam plate portion 32, the durability and pressure resistance are further improved. Yes.
The mold 30 has a hollow shape in which a dam plate portion 32, a side plate portion 33 and a reinforcing plate portion 35 are integrally formed with two plates 36 and a plurality of long reinforcing ribs 37 connecting them. Therefore, it is lightweight and has sufficient mechanical strength and translucency. In particular, since the inclined rib 47 is formed in the dam plate portion 32, the bending rigidity is high, and the dam plate portion 32 does not bend due to the pressure of the concrete at the time of placing the concrete.

In addition, the concrete placement form of this invention is not limited to what is shown in FIG.
Moreover, the protruding line part should just be provided in the outer surface of at least one side plate part, and does not necessarily need to be provided in the outer surface of the side plate part of both sides.
Further, the position of the ridge portion is not limited to the position of the illustrated example, and one ridge portion of the two ridge portions extending in the vertical direction is a concrete placement surface whose one side surface is a dam plate portion. If it is made into the same plane, the other protruding item | line part does not need to be provided in the side edge of a side-plate part like the example of illustration.
Moreover, as a separator used in the case of installation of the formwork 30, it is not limited to the round-bar-shaped thing of an example of illustration, For example, well-known separators, such as a flat-plate-like thing, can be used.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Example 1]
70 parts by mass of a propylene-ethylene block copolymer having a melt mass flow rate (MFR) of 0.5 g / 10 min and an ethylene content of 8.5% by mass (in total of 100% by mass of the propylene-ethylene block copolymer and the inorganic filler) , 70% by mass), 30 parts by mass of talc having an average particle size of 10 μm (30% by mass in a total of 100% by mass of propylene-ethylene block copolymer and inorganic filler), 0.25 parts by mass of hindered amine light stabilizer , And 0.25 parts by mass of the ultraviolet absorber were supplied to the extruder and kneaded, and extruded from the mold at an extrusion temperature of 220 ° C. to obtain a mold 30 as shown in FIG.
The mold 30 has a height of 2400 mm, a width of the dam plate portion 32 of 600 mm, a thickness of the dam plate portion 32 of 12 mm, a thickness of the side plate portion 33 and the reinforcing plate portion 35 of 18 mm, a plate forming a hollow panel, and a reinforcement The rib thickness was 2 mm.

A test piece having a predetermined size was cut out from the mold 30 and evaluated by the following method.
(Bending test)
A 1000 mm specimen was cut out from the mold 30 in the height direction. Referring to the Japan Agricultural Standards (JAS) “Bending rigidity test of plywood for concrete formwork”, as shown in FIG. 6, the test body 61 is supported by support bases 62 and 62 so that the bending span is 900 mm. A concentrated line load was applied to the center with the pressure support 63, and the amount of deflection of the specimen was measured. An Instron (manufactured by Shimadzu Corporation) was used as a testing machine, and the test was performed at 23 ° C. and 50% RH at a deflection rate of 6 mm / min at the center. The results are shown in FIG.

(Falling ball impact test)
A 300 mm specimen was cut out from the mold 30 in the height direction. As shown in FIG. 8, the test specimen 71 was placed on the floor, and 1 kg of a steel ball 73 was dropped from the predetermined height in the center under the condition of 23 ° C. to confirm whether the test specimen 71 was damaged. When the height at which the steel ball was dropped was increased from 0.5 m in increments of 0.1 m, no damage was observed up to a height of 1 m.

(Translucency test)
As shown in FIG. 9, the illuminometer 82 was placed in a box 81 (width 50 cm × depth 50 cm × height 60 cm) opened upward. When the brightness in the enclosure 81 was measured outdoors, it was 2000 lux.
Next, the opening of the enclosure 81 was covered with the dam plate portion 32 side of the mold 30. When the brightness in the enclosure 81 was measured outdoors, it was 450 lux.
Furthermore, the opening of the enclosure 81 was covered with a plywood (12 mm thickness) for formwork. When the brightness in the enclosure 81 was measured outdoors, it was 0 lux.
Thus, it was found that the brightness of about 1/4 of the outer side can be secured even on the inner side covered with the mold 30. The brightness of 450 lux is almost equivalent to the brightness at a location 30 cm away from the 60 W incandescent bulb (500 lux).

(Weather resistance test)
A weather resistance test was conducted according to JIS A 1415 “Accelerated exposure test for plastic building materials” (test conditions: black panel temperature 63 ± 3 ° C., spray cycle 120 minutes 18 minutes, bath temperature 43 ± 2 ° C.). Specifically, the material used for the mold 30 was extruded to a width of 40 mm and a thickness of 2 mm, and this was subjected to an accelerated test, then cut into a predetermined size to obtain a test piece, and the tensile strength was measured.
The tensile strength of the test piece after the 500 hour accelerated test was almost equal to the tensile strength of the test piece before the accelerated test.

(Machinability)
When the formwork was cut with a rotary blade for woodworking (round saw), it could be cut without generating burrs.

The concrete casting mold of the present invention is superior in both bending rigidity and impact resistance, and has the same machinability as that of a conventional plywood mold. It can be handled in the same way as the plywood formwork.
Moreover, the concrete casting form of the present invention has good translucency, and external light can be taken into the concrete placing site surrounded by the form.

It is a perspective view which shows an example of the formwork for concrete placement of this invention. It is a top view of the formwork for concrete placement of FIG. It is sectional drawing which shows a mode that the penetration hole for separator penetration is drilled in the contact part of the molds for concrete placement. It is a perspective view which shows an example of the installation form of the formwork for concrete placement of this invention. It is a principal part perspective view which shows an example of the state which made the formwork connected continuously. It is a figure which shows the mode of a bending test. It is a graph which shows the result of a bending test. It is a figure which shows the mode of a falling ball impact test. It is a figure which shows the mode of a translucency test.

Explanation of symbols

30 Formwork (Concrete casting formwork)
31 Concrete Placing Surface 32 Weir Plate Part 33 Side Plate Part 34 Back Side 35 Reinforcement Plate Part 36 Plate 37 Reinforcement Rib 38 Outer Surface 41 Convex Part 42 Convex Part 43 Inclined Surface 46 Right Angle Rib (Reinforcement Rib)
47 Inclined rib (Reinforcement rib)

Claims (8)

A resin composition comprising a propylene-ethylene block copolymer having a melt mass flow rate (MFR) of 0.3 to 4.0 g / 10 min, and a particulate inorganic filler having an average particle size in the range of 1 μm to 20 μm. Consists of
A concrete casting form, wherein a mass ratio of propylene-ethylene block copolymer and inorganic filler (propylene-ethylene block copolymer / inorganic filler) is 60/40 to 95/5.   The said resin composition is 0.01-2.0 mass parts hindered amine light stabilizer with respect to a total of 100 mass parts of a propylene-ethylene block copolymer and an inorganic filler, and 0.01-2.0. The formwork for concrete placement according to claim 1, further comprising a part by weight of an ultraviolet absorber.   The concrete placement form according to claim 1 or 2, wherein the inorganic filler is talc.   4. The concrete casting form according to claim 1, wherein the inorganic filler has an average particle size of 3 μm to 20 μm.   2. A dam plate portion, one side of which is a concrete placement surface, and a side plate portion bent at right angles from both side edges of the dam plate portion to the opposite side of the concrete placement surface of the dam plate portion. 4. The concrete casting form according to any one of 4 above.   On the outer surface of at least one of the side plate portions, two protruding ridge portions extending in the vertical direction are projected, and one side surface of the one ridge portion is flush with the concrete placement surface of the dam plate portion. The concrete casting form according to claim 5, wherein:   6. The dam plate portion and the side plate portion are hollow panels in which two plates and a plurality of long reinforcing ribs connecting the plates and extending in the vertical direction are integrally formed. Or the concrete placement form of Claim 6. The formwork for concrete placement according to any one of claims 5 to 7, wherein a reinforcing plate portion parallel to the side plate portion is provided on the back surface of the concrete placement surface of the dam plate portion.

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