KR102590220B1 - Rigidity reinforced pipe - Google Patents

Abstract

The present invention relates to a pipe, and more specifically to a rigidity-reinforced pipe with improved rigidity. The present invention relates to the rigidity-reinforced pipe, including a polyolefin-based matrix; an adjuvant; a filler; and a shrinkage control agent.

Description

Rigidity reinforced pipe}

The present invention relates to a pipe pipe, and more specifically, to a rigidity-reinforced pipe pipe with improved rigidity.

In general, sewer pipes, water pipes, sewage pipes, waste water pipes, etc. buried underground are buried at a certain depth underground, and considering their installation location, they have a certain degree of ductility and have higher strength, durability, and chemical resistance than pipes exposed to the outside. , water resistance, etc. are required. To meet these needs, pipes made using synthetic resins are widely used to date. Pipes made of synthetic resins have the additional advantage of being able to be used semi-permanently as they do not rust or rot even when exposed to corrosive substances present in the soil. .

For this reason, pipes made of synthetic resin are widely used not only in various industrial fields such as agricultural waterways buried in the ground, sewage pipes for wastewater and rainwater pipes, and industrial piping materials for highly toxic wastewater, but also in everyday life.

For pipes made of synthetic resin, various manufacturing methods and suitable manufacturing equipment have been developed, such as melt-extruding the synthetic resin composition that makes up the pipe using a tubular mold, or extruding it into a sheet with a predetermined width and then wrapping it in a spiral and heat-sealing it. It is done.

In addition, in order to sufficiently demonstrate the watertightness, ductility, impact resistance, and strength of the pipe to be implemented, it is possible to have a structure in the form of a multi-layered pipe where several layers are stacked to form a pipe, or to layer a material that can reinforce mechanical properties. Pipes are implemented by providing them in a matrix.

However, the pipes developed to date do not have sufficient physical properties such as rigidity, and when strengthening the rigidity, etc., it becomes difficult to control the shrinkage rate and smoothness between the direction in which the synthetic resin composition is extruded and the direction perpendicular to this direction, making it difficult to manufacture more watertight pipes. There is a problem.

Registered Patent Publication No. 10-1612028

The present invention was developed in consideration of the above points. By controlling the shrinkage characteristics and smoothness that occur differently depending on the direction during extrusion, it is possible to achieve high watertightness and improved ductility, impact resistance, and rigidity, and to provide an extruded pipe. The purpose is to provide a rigidity-reinforced pipe pipe suitable for a spiral method in which a pipe forming composition is wound in a spiral shape to form a pipe pipe.

In order to solve the above-described problem, the present invention provides an inner layer, a middle layer, and an outer layer arranged from a hollow penetrating in a first longitudinal direction to an outer direction perpendicular to the longitudinal direction, wherein the middle layer includes a polyolefin-based matrix; and a reinforcing agent comprising metal foil flakes and glass fibers dispersed in the polyolefin-based matrix.

According to one embodiment of the present invention, the polyolefin-based matrix may include one or more of polyethylene and polypropylene.

According to another embodiment of the present invention, the metal foil flake may be an aluminum foil flake.

According to another embodiment of the present invention, the reinforcing agent may be included in an amount of 25 to 60 parts by weight based on 100 parts by weight of the polyolefin-based matrix.

According to another embodiment of the present invention, the metal foil flake has a first aspect ratio (a/b), which is the ratio to the length (a) and width (b), of 1.5 or more, and the glass fiber has a length (m) and a diameter. The second aspect ratio (m/n), which is the ratio to (n), may be 150 or more.

According to another embodiment of the present invention, the glass fiber may have a diameter of 5 to 20 μm and a length of 1.2 to 5.0 mm.

According to another embodiment of the present invention, the intermediate layer includes a filler contained in an amount of 20 to 50 parts by weight based on 100 parts by weight of the polyolefin-based matrix, and a shrinkage control agent that is a talc powder contained in an amount of 2 to 3.5 parts by weight based on 100 parts by weight of the filler. It may further include.

According to another embodiment of the present invention, the talc powder may have a diameter of 3 to 5 μm.

According to another embodiment of the present invention, the intermediate layer may be formed by spirally winding an intermediate layer forming sheet extruded to have a predetermined width so that one side of the intermediate layer forming sheet overlaps each other along the outer peripheral surface of the inner skin layer in the first direction. .

The pipe according to the present invention has higher watertightness and can exhibit improved ductility, impact resistance, and rigidity as the shrinkage characteristics and smoothness are controlled during the manufacturing process, so it can be used in underground pipes such as sewer pipes, water pipes, sewage pipes, and waste water pipes. It can be widely used as a buried pipe.

1 is a cutaway perspective view and a partially enlarged view of a pipe according to an embodiment of the present invention.
Figure 2 is a schematic diagram of a manufacturing device used to manufacture pipes according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention.

Figure 1 is a cross-sectional perspective view of a rigid reinforced pipe 100 according to an embodiment of the present invention, from a hollow P penetrating in a first longitudinal direction d1 to an outer direction perpendicular to the longitudinal direction d2. ) is implemented by arranging the inner layer 10, the middle layer 20, and the outer layer 30.

The intermediate layer 20 constitutes the body of the pipe and functions to give the shape and mechanical properties of the pipe. The intermediate layer 20 includes a polyolefin-based matrix 21 forming the body and a reinforcing agent 24 to improve mechanical properties such as flexural elasticity, flexural strength, tensile strength, and impact strength.

The polyolefin-based matrix 21 forms the body of the middle layer and is formed by mainly including a typical polyolefin-based resin used in pipes. Here, inclusion as a subject means more than 80% by weight of the resin forming the matrix, as an example, more than 85% by weight, as another example, more than 90% by weight, or more than 95% by weight.

The polyolefin-based resin may include one or two or more types such as polyethylene, polypropylene, polybutene, ethylene vinyl acetate copolymer, and ethylene-◎olefin copolymer. Preferably, in terms of strength and improvement in elongation at high temperatures, it may be polyethylene and/or polypropylene, more preferably it may contain polyethylene, and even more preferably may be made of polyethylene.

The polyethylene (PE) may be one or more of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE). In addition, polypropylene (PP) may include homo polypropylene, block polypropylene, etc. Moreover, examples of polybutene include polybutene-1. Ethylene-◎olefin copolymer is a copolymer in which ◎olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, or 1-octene are copolymerized with respect to ethylene in a ratio of about several mole percent. A chain is preferable.

Meanwhile, when polyethylene is preferably used, it is better to use polyethylene with an average degree of polymerization of 800 to 1,000. If polyethylene with a degree of polymerization of less than 800 is used, there is a risk of a decrease in tensile strength, and if polyethylene with a degree of polymerization of more than 1,000 is used, there is a risk of a decrease in processability.

Next, the reinforcing agent 24 dispersed in the polyolefin-based matrix 21 may be used without limitation if it is a typical reinforcing agent used to reinforce the strength of pipes, but the present invention provides increased impact resistance, flexural elasticity, and flexural strength. , it includes metal foil flakes (22) and glass fibers (23) as reinforcing agents (24) to achieve tensile strength and rigidity.

The metal foil flakes 22 are made by cutting and pulverizing metal foil to a predetermined size, and play a role in increasing the ductility and impact resistance of the pipe. The metal foil flakes can be used without limitation in the case of known metal foils, but are preferably aluminum foil flakes, through which a synergistic effect with the glass fiber 23 is achieved compared to the case of using metal foil flakes of other materials. It is advantageous to do so.

The thickness of the metal foil flake 22 may be that of a commonly commercialized metal foil, and the present invention is not particularly limited thereto. In addition, the metal foil flakes 22 may have an amorphous shape, but are preferably cut and pulverized to have a length longer than the width in one direction, more preferably length (a) and width (b). It may be cut and pulverized so that the first aspect ratio (a/b) is 1.5 or more, more preferably 2.0 or more, and even more preferably 2.0 to 10.0, and through this, ductility and In addition to impact resistance, it can be advantageous in developing increased flexural modulus and tensile strength in combination with glass fiber, which will be described later.

Meanwhile, the metal foil flakes 22 may be made of commercialized metal foil itself, but may be derived from metal foil film waste used as a packaging material in terms of resource recycling. The metal foil film is a multi-layer laminated film layer of polyethylene terephthalate, polyethylene, polypropylene, etc., and a metal foil layer, and is a typical metal foil film used for packaging various foods, electronic components such as semiconductors, and electronic devices. It can be used without restrictions.

Next, the glass fiber 23 that forms the reinforcing agent 24 together with the metal foil flake 22 described above will be described.

The glass fiber 23 greatly improves the mechanical strength of the pipe implemented by using only the metal foil flake 22 as a reinforcing agent, and in particular has an increased effect on impact resistance, tensile strength, and flexural modulus. The glass fibers can be used without limitation in the case of glass fibers that typically function as reinforcing agents in polymer resins. For example, they may have a composition classified as E-class or S-class in the art, and the present invention specifically addresses this. It is not limited.

In addition, the glass fiber 23 preferably has a second aspect ratio (m/n), which is the ratio of the length (m) and the diameter (n), of 150 or more, more preferably 200 or more, and in another example, 600 or less, More preferably, it may be 450 or less. If glass fibers with a second aspect ratio of less than 150 are provided, it is difficult for the glass fibers to be oriented in a spirally wound direction during the process of forming the intermediate layer through the spiral method, and there is a risk that sufficient mechanical strength may not be achieved due to this. In addition, when the aspect ratio exceeds 600, there is a risk that some elements penetrate the outer surface of the middle layer and the orientation within the matrix may deteriorate.

In addition, the glass fiber 23 may have a diameter of 5 to 20 ㎛ and a length of 1.2 to 5.0 mm, through which the glass fiber 23 may move in any one direction within the middle layer 20, for example, in the middle layer. It is advantageous for the intermediate layer forming sheet, which forms the intermediate layer while being perpendicular to the thickness direction, to be oriented in a spirally wound direction, and through this, more improved mechanical properties can be achieved. If the length of the glass fiber 23 exceeds 5.0 mm, during the process of forming the middle layer through the spiral method, the glass fiber may not be oriented along the direction in which it is wound spirally, and one end may protrude outward through the outer surface of the middle layer. This is high, and because of this, it may be difficult to achieve sufficient mechanical strength such as impact resistance. In addition, if the length of the glass fiber is less than 1.2 mm, it is difficult to orient the glass fiber in any one direction, specifically parallel to the direction in which the middle layer forming sheet is wound and perpendicular to the thickness direction of the middle layer, and as a result, mechanical strength such as tensile strength decreases. may deteriorate.

Meanwhile, as a reinforcing agent, it may further contain a different type of fibrous reinforcing agent other than glass fiber. The heterogeneous fibrous reinforcing agent may be, for example, carbon fiber, synthetic resin fiber, and cellulose-based fiber, and the present invention is not particularly limited thereto.

In addition, the above-described reinforcing agent 24 may be included in an amount of 25 to 60 parts by weight, more preferably 35 to 50 parts by weight, based on 100 parts by weight of the polyolefin-based matrix 21. If the reinforcing agent is contained in less than 25 parts by weight, the supplementation of mechanical strength through the reinforcing agent may be minimal. In addition, when the reinforcing agent exceeds 50 parts by weight, the impact resistance of the middle layer decreases, and there is a high risk of damage such as cracks. In addition, during extrusion, there is a risk of excessive shrinkage in the TD direction perpendicular to the MD direction, which is the direction in which the molten intermediate layer forming composition flows through the injection port, and the content of talc powder, which will be described later, is relatively reduced, resulting in excessive shrinkage in the TD direction. Control can be difficult.

In addition, the reinforcing agent 24 may be, for example, a mixture of metal foil flakes 22 and glass fiber 23 at a weight ratio of 1:3 to 5, which may be more advantageous in achieving the purpose of the present invention.

According to one embodiment of the present invention, the intermediate layer 20 may further include a filler and a shrinkage control agent such as talc powder.

The filler is included to improve the hardness and durability of the pipe and reduce production costs. Known fillers used in pipes can be used without limitation, but preferably one of calcium carbonate and hydrotalcite. Or a mixture thereof may be included. When using calcium carbonate or hydrotalcite, if the above-mentioned metal foil flakes are derived from metal foil film waste, it is necessary to prevent a decrease in strength due to mixing of the polymer film materials that make up the metal foil film, which may inevitably be included in the polyolefin matrix. It may be more advantageous.

Meanwhile, the filler may be included in an amount of 20 to 50 parts by weight based on 100 parts by weight of the polyolefin-based matrix. If the filler is contained in less than 20 parts by weight, the effect achieved through the above-mentioned filler may be minimal. Additionally, if the filler exceeds 50 parts by weight, the content of matrix components, reinforcing agents, etc. may be relatively reduced, making it difficult to achieve the purpose of the present invention.

In addition, the shrinkage control agent, which is talc powder, serves as a reinforcing agent to improve the shrinkage rate deviation and low smoothness that occur after the intermediate layer forming composition containing glass fiber is melted and extruded.

In other words, it is possible to create a pipe with greater mechanical properties by mixing glass fiber with metal foil flakes as a reinforcing agent. In this case, the pipe has high watertightness due to the variation in shrinkage rate and low smoothness of the middle layer that occurs during the manufacturing process of the pipe. may be difficult to implement. Specifically, the glass fiber with a large second aspect ratio is generally oriented so that the machine direction (MD) in which the intermediate layer forming composition is extruded is the longitudinal direction of the glass fiber when the intermediate layer forming composition is extruded. This has the advantage of greatly preventing shrinkage in the MD direction. This causes a problem in which shrinkage in the TD direction becomes even larger. In this case, in the process of manufacturing the middle layer by extruding it to have a predetermined width and then winding it in a spiral shape, the overlapping area on the side of the middle layer forming sheet becomes uneven, and the middle layer becomes unstable. Due to the reduced smoothness of the formed sheet, there are parts in the overlapped area that are not in close contact, which may cause the side effect of lowering the watertightness of the formed intermediate layer. However, when talc powder is added as a shrinkage control agent, both the TD direction shrinkage and the thickness direction shrinkage of the intermediate layer forming sheet are controlled, which may be advantageous for forming a more water-tight intermediate layer.

However, the talc powder used as a shrinkage control agent may have a diameter of 3 to 5㎛, and if it contains large-sized talc powder exceeding 5㎛ in diameter, it is difficult for the talc powder to act as a nucleating agent, so it functions as a filler instead. There is a risk that it may not function as a contraction control agent. Additionally, if the diameter of the talc powder is less than 3㎛, it may be difficult to control the smoothness and shrinkage characteristics to the desired level.

The shrinkage control agent, which is the talc powder, may be contained in an amount of 2 to 3.5 parts by weight based on 100 parts by weight of the filler, which may be more advantageous in achieving the purpose of the present invention. If the shrinkage control agent is contained in less than 2 parts by weight, the shrinkage control effect may be minimal, and if it exceeds 3.5 parts by weight, there is a risk that impact resistance may be reduced.

Meanwhile, other than the above-mentioned talc powder, ingredients such as silica, mica, calcium carbide, and titanium dioxide may not be suitable as shrinkage control ingredients, and in particular, even when they have the same particle size as the above-mentioned, they do not exhibit a shrinkage control effect at the level of talc. It can be difficult.

According to one embodiment of the present invention, in addition to the above-mentioned components, the intermediate layer 20 contains known additives contained in pipes such as impact modifiers such as rubber resins, stearic acid to suppress cracks, and dispersants such as citrate. Additional features may be provided, and detailed descriptions and examples thereof are omitted in the present invention.

In addition, the inner layer 10 is disposed on the inner side of the above-described middle layer 20 in the hollow (P) direction, and the outer layer 30 is disposed on the outer side. The inner layer 10 and the outer layer 30 supplement the watertightness and mechanical strength of the pipe, and physically and chemically protect the middle layer 20 from the liquid flowing through the hollow P and the external environmental conditions in which the pipe is buried. It functions as a protective layer.

The inner layer 10 and the outer layer 30 may be made of any material that typically forms the inner and outer surfaces of the pipe, and may be made of polyolefin-based resin, which is the same material as the body of the middle layer. , More preferably, the middle layer 20, the inner layer 10, and the outer layer 30 are formed of the same material in consideration of adhesion and bonding characteristics at the interfaces formed respectively.

In addition, the thickness of the inner layer 10, the middle layer 20, and the outer layer 30 is the thickness of each layer in a typical pipe pipe having a three-layer structure in consideration of the inner diameter of the pipe to be implemented and the required physical properties. Since the can be adopted or modified appropriately, the present invention is not particularly limited thereto.

The pipe 100 according to an embodiment of the present invention described above is manufactured by a manufacturing method described later, but is not limited thereto.

The pipe 100 can be manufactured through a spiral method known as a pipe manufacturing method. Specifically, the pipe 100 is made by inserting a middle layer forming composition forming the middle layer 20, an inner skin layer forming composition forming the inner skin layer 10, and an outer skin layer forming composition forming the outer skin layer 30, respectively, into separate extruders. After melt extrusion, the inner layer forming sheet is extruded in a spiral shape so that the inner layer forming sheet is in close contact with the inside of the middle layer forming sheet, and the outer layer forming sheet is extruded in a spiral shape so that the outer layer forming sheet is in close contact with the outside of the middle layer forming sheet, and then bonded at the interface of each extruded sheet to form an integrated piece. A pipe 100 forming a can be formed.

More specifically, in the process of first winding the inner layer forming sheet in a spiral manner in the first direction so that the inner layer forming sheet has a hollow of a predetermined diameter on the inner side, the intermediate layer forming sheet is formed so that a partial area on one side overlaps again with the outer side of the wound inner skin layer forming sheet. It can be spirally wound in one direction to form the middle layer, and in the process of forming the middle layer, the outer skin layer forming sheet can be spirally wound in the first direction so that some areas on one side overlap with the outside of the middle layer forming sheet to form the outer skin layer. there is. At this time, the formation process of the inner, middle, and outer layers may begin at a predetermined time interval, but is not limited thereto.

Specifically, the above-described manufacturing method can be performed through the pipe manufacturing apparatus described below. Referring to FIG. 2, the pipe manufacturing apparatus includes an intermediate layer extruder 1000 that melts and extrudes the intermediate layer forming composition, and is in close contact with the inner peripheral surface of the intermediate layer formed by extrusion from the intermediate layer extruder 1000 to extrude the inner layer. It is configured to include an inner layer extruder (2000) and an outer layer extruder (2100) that extrudes the outer peripheral surface of the middle layer in close contact to form an outer layer.

The middle layer extruder 1000 includes a primary crushing melter 1100 in which waste metal foil film is primarily crushed and melted to produce the above-described metal foil flakes, and a primary crushing melter 1100 that flows in from the primary crushing melter 1100. It is configured to include a secondary melter (1200) that secondarily melts recycled materials. Although not shown in the drawing, each input means for glass fiber as a polyolefin-based matrix component and reinforcing agent is connected to the primary crushing melter 1100, so that melting can be achieved by mixing with the pulverized waste metal foil film.

In addition, the intermediate layer forming composition melted in the secondary melter 1200 flows into the hopper-shaped distribution box 1118 and is extruded downward while rotating the tensioner 4000 located below the distribution box 1118. It can be wound around the roller 4300 in layers. The tensioner 4000 is provided with a rotating roller 4300 rotated by a motor, and the rotating roller 4300 is formed of a plurality of rollers.

In addition, the inner skin layer extruder 2000 is for melting and extruding synthetic resin raw materials, and is formed with a raw material inlet 2020 for introducing the inner skin layer forming composition, and heats the input composition to melt it so that it can be extruded. The raw material heated to around ℃ and melted is transferred to the tensioner 4000, where the extrusion die or guide is attached, and a detailed description of the inner layer extruder 2000 will be omitted.

In addition, the outer skin layer extruder 2100 is for melting and extruding the outer skin layer forming composition like the inner skin layer extruder 2000. A raw material inlet 2020 is formed for introducing the outer skin layer forming composition, and the input raw material is heated and extruded. It consists of a body 2121 that is heated to around 200°C and transfers the molten plastic raw material to the tensile machine 4000 in order to melt it. At the end of the body 2121, there is a body 2121 that discharges the raw material toward the tensile machine 4000. An outer layer discharge pipe 220 may be formed.

The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, and should be interpreted to aid understanding of the present invention.

<Example 1>

Polyethylene resin was prepared with an inner skin layer forming composition and an outer skin layer forming composition. In addition, as an intermediate layer forming composition, aluminum foil flakes (A) cut and pulverized to have a first aspect ratio of 2.0 to 3.5 and glass fibers (B) with a second aspect ratio of 208 (average diameter 10 ㎛, average length 2.08 mm) A reinforcing agent mixed in a weight ratio of 1:3 is mixed in an amount of 45 parts by weight based on 100 parts by weight of a polyethylene resin with a degree of polymerization of 950, and based on 100 parts by weight of the polyethylene resin, 38 parts by weight of a filler of calcium carbonate, 5 parts by weight of an impact modifier of MBS, and stear are added. 0.03 parts by weight of acid and 3.0 parts by weight of talc powder with an average particle diameter of 3.8㎛ as a shrinkage control agent were prepared by adding and mixing an additional 3.0 parts by weight based on 100 parts by weight of the above filler. Afterwards, the prepared composition was put into the inner layer extruder, middle layer extruder, and outer layer extruder of the production equipment shown in Figure 2 to manufacture the pipe pipe using the spiral method. At this time, the outer diameter of the pipe was 265 mm, the thickness was 25 mm, the thickness of the inner layer, middle layer, and outer layer was 1:4.5:1, and the middle layer forming sheet overlapped when wound in a spiral shape on the inner layer in the first direction. The width of the side part was adjusted to 5 mm.

<Examples 2 to 5>

The pipe was manufactured in the same manner as in Example 1, but the composition and/or mixing ratio of the intermediate layer forming composition was changed as shown in Table 1 below.

At this time, in Examples 4 and 5, the diameter of the glass fiber was the same, but the length was changed so that the aspect ratio was 155 and 130, respectively.

<Comparative Example 1>

The pipe was manufactured in the same manner as in Example 1, but the composition and/or mixing ratio of the intermediate layer forming composition was changed as shown in Table 1 below.

<Experimental Example 1>

After measuring the stiffness according to the KPS M 2009 test method and the tensile strength according to the ASTM D 638 test method for the pipes manufactured through Examples 1 to 5 and Comparative Example 1, the measured value of Comparative Example 1 was set to 100. The measured values of each example were converted into relative values as a reference and shown in Table 1 below.

middle layer Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 matrix Material/content
(part by weight) PE/100 PE/100 PE/100 PE/100 PE/100 PE/100 adjuvant A aspect ratio 2.0 ~ 3.5 2.0 ~ 3.5 1.0 ~ 1.3 2.0 ~ 3.5 2.0 ~ 3.5 2.0 ~ 3.5 B aspect ratio 208 208 208 155 130 Not included A:B weight ratio 1:03 1:03 1:03 1:03 1:03 - Content (parts by weight) 45 45 45 45 45 45 Shrink
control agent Material/average particle size
(㎛)/content Talc/3.8/3.0 Not included Talc/3.8/3.0 Talc/3.8/3.0 Talc/3.8/3.0 Talc/3.8/3.0 Properties
(%) hardness 175.0 124.4 160.0 156.9 135.2 100 tensile strength 562.5 342.3 416.2 505.0 433.8 100

As can be seen in Table 1,

It can be seen that the stiffness and tensile strength of the Examples were greatly improved compared to Comparative Example 1, which did not include glass fiber. However, in the case of Example 2, which did not include a shrinkage control agent, the extent of improvement was small compared to the other Examples. It was not large, which is expected to be due to internal residual stress due to uncontrolled shrinkage characteristics.

<Examples 6 to 8>

The pipe was manufactured in the same manner as in Example 1, but the composition and/or mixing ratio of the intermediate layer forming composition was changed as shown in Table 2 below.

<Comparative Example 2>

A pipe as shown in Table 2 below was manufactured in the same manner as in Example 1, except that glass fiber and shrinkage control agent were not included.

<Experimental Example 2>

The intermediate layer forming compositions used in Examples 1 to 2, Examples 6 to 8, and Comparative Examples 1 to 2 were added in equal amounts to identically set intermediate layer extruders and wound on a predetermined roller at the same speed. Afterwards, measure the width of a total of 50 points at 5cm intervals in the length direction starting from a point 5cm (measurement start point) from one end of the wound middle layer in the longitudinal direction, and then calculate the width average and standard deviation for the measurements at 50 points. Afterwards, width uniformity was calculated according to the formula below to evaluate whether shrinkage occurred evenly. The closer the width uniformity value is to 0%, the more uniform the shrinkage occurs.

Width uniformity (%) = [50 points width standard deviation (cm) / 50 points average width (cm)] × 100

Example 1 Example 2 Example 6 Example 7 Example 8 Comparative Example 1 Comparative example 2 matrix Material/content
(part by weight) PE/100 PE/100 PE/100 PE/100 PE/100 PE/100 PE/100 adjuvant A aspect ratio 2.0 ~ 3.5 2.0 ~ 3.5 2.0 ~ 3.5 2.0 ~ 3.5 2.0 ~ 3.5 2.0 ~ 3.5 2.0 ~ 3.5 B aspect ratio 208 208 208 208 208 Not included Not included A:B weight ratio 1:03 1:03 1:03 1:03 1:03 - - content
(part by weight) 45 45 45 45 45 45 45 Contraction control agent Material/average particle diameter (㎛)/content (parts by weight) Talc/3.8/3.0 Not included SiO ₂ /3.8/3.0 _TiO2 /3.8/3.0 Talc/10/3.0 Talc/3.8/3.0 Not included Shrinkage characteristics Width uniformity
(%) 2.4 32.5 26.8. 25.1 30.9 2.4 2.5

As can be seen through Tables 1 and 2,

When glass fibers are included, mechanical properties can be improved, but as can be seen from the comparison between Example 2 and Comparative Example 2, it can be seen that the glass fibers can cause width unevenness in the width direction.

However, in Example 1, where talc powder with an average particle diameter of 3.5 ㎛ or more as a shrinkage control agent was provided, the width unevenness in the width direction was significantly reduced compared to Example 2, and through this, the middle layer forming sheet was formed on one side through a spiral method. It can be expected that in the process of winding in a spiral manner to overlap, the overlapping area can be formed more uniformly in Example 1 than in Example 2, and as a result, the water tightness of the implemented pipe pipe in Example 1 is superior to that in Example 2. can be expected.

On the other hand, it can be seen through Examples 6 and 7 that when a material other than talc of similar particle size is contained as a shrinkage control agent, the shrinkage control properties are hardly developed.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in the present specification, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same spirit. , other embodiments can be easily proposed by change, deletion, addition, etc., but this will also be said to be within the scope of the present invention.

Claims (9)

An inner layer, a middle layer, and an outer layer are arranged from the hollow penetrating in the first longitudinal direction to the outer direction perpendicular to the longitudinal direction,
The intermediate layer is a polyolefin-based matrix;
Aluminum foil flakes having a first aspect ratio (a/b) of 1.5 to 10.0, which is the ratio of the length (a) and width (b) dispersed in the polyolefin matrix, and the ratio of the length (m) and diameter (n) A reinforcing agent comprising glass fibers having a second aspect ratio (m/n) of 150 to 600;
A filler that is one of calcium carbonate and hydrotalcite, or a mixture thereof, and is contained in an amount of 20 to 50 parts by weight based on 100 parts by weight of the polyolefin-based matrix; and
A rigid reinforced pipe containing a shrinkage control agent, which is a talc powder containing 2 to 3.5 parts by weight based on 100 parts by weight of the filler and having a diameter of 3 to 5 ㎛. According to paragraph 1,
The polyolefin-based matrix is a rigid reinforced pipe containing at least one of polyethylene and polypropylene. delete According to paragraph 1,
A rigid reinforced pipe containing the reinforcing agent in an amount of 25 to 60 parts by weight based on 100 parts by weight of the polyolefin-based matrix. delete According to paragraph 1,
The glass fiber is a rigid reinforced pipe pipe with a diameter of 5 to 20㎛ and a length of 1.2 to 5.0mm. delete delete According to paragraph 1,
An inner layer, a middle layer, and an outer layer are disposed in the outer direction from the hollow penetrating in the first longitudinal direction,
The intermediate layer is a rigid reinforced pipe pipe, characterized in that the intermediate layer forming sheet extruded to have a predetermined width is wound spirally around the outer peripheral surface of the inner skin layer in a first direction so that one side of the intermediate layer forming sheet overlaps each other.

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