KR101127601B1 - Polyethylene resin composition and method for manufacturing the undreground water pipe using thereof - Google Patents

Abstract

PURPOSE: A polyethylene resin composition and a manufacturing method of polyethylene resin water supply and drainage pipe using thereof are provided to improve mechanical property of the polyethylene resin by mix proper quantity of carbon fiber with high density polyethylene resin. CONSTITUTION: A polyethylene resin composition is manufactured by mixing maleic anhydride grafted polyethylene which includes 5-20 parts by weight of maleic based on 100.0 parts by weight of polyethylene resin. The polyethylene resin includes 70-99 weight% of high density polyethylene resin which has average density of 0.941-0.965 g/ml, 1-30 weight% of either non-sizing carbon fiber sizing agent.

Description

Polyethylene resin composition and method for manufacturing a polyethylene resin water and sewage pipe using the same

The present invention relates to a polyethylene resin composition, and more particularly to a polyethylene resin composition for water pipes containing carbon fibers.

Conventionally, the places where water and sewage work were made with cast iron pipes are not functioning due to the blockage and cracking caused by oxidation before and after the rainy season in the country. Iron oxide in the pipe not only threatens people's health, but iron oxide is difficult to remove unless it is broken and replaced. Removing iron oxide also has the side effect of rust coming back within a few years.

Polyethylene (PE) pipe is one of the water pipes currently used, and PE is excellent in chemical resistance without being eroded from acid and alkali.It is widely used in chemical transport pipes, industrial wastewater treatment pipes, landfill leachate transport pipes, and corrosion to salt. As a result, it is applied to various types of water pipes, shaft farms and offshore cage farms. In addition, as a non-conductor of complete electricity, it is used as a power line protection tube because there is no electrical corrosion, and PE pipe does not produce any harmful substances to the human body from materials, and also does not produce scales because bacteria and other bacteria cannot be easily reproduced. Since the purity of the contents is maintained even for a long time, it is recognized as the most suitable piping agent for water supply pipe applications. The internal friction on the inside is smaller than the pipe material of other materials, and the scale is not pinched to minimize the head loss of fluids.

In addition, it is excellent in flexibility and easy to install in curved areas with small angles without using curved pipes. Even though the Kobe earthquake or summer flood damage caused the pipes in various grounds to burst, the PE pipe remains almost intact, proving its flexibility and superior in abrasion resistance than other materials. It is used for such. It is light in weight and easy to handle and fast in bonding. It is relatively easy than other materials, and the fusion splicing system is perfect, so there is no fear of leakage. In addition, there is no change in the physical properties of the raw material PE up to -80, so it does not become a freezing wave, and due to the material properties, it is not broken by external impact.

However, despite these excellent properties, PE pipes are only applied to small pipes because of pipe deformation problems. Therefore, there is a need to develop a PE resin applicable to large pipes such as water and sewage pipes by improving the mechanical properties of PE.

The present invention, despite the excellent physical properties, PE resin that is applied only to small pipes due to problems of pipe deformation, in particular, high density polyethylene resin (HDPE) by mixing a suitable amount of carbon fiber to improve the mechanical properties of PE resin PE water conduit It is a problem to provide a polyethylene resin composition that can be applied to.

In addition, another object of the present invention is to provide a method for producing a PE tube made of a polyethylene resin material that can be used as a water and sewage pipe as a large pipe using a polyethylene resin composition having increased mechanical properties.

Polyethylene resin composition of the present invention solved the above problems in the polyethylene resin composition for water and sewage pipe production,
70 to 99% by weight of a high density polyethylene resin having an average density of 0.941 to 0.965 g / ml, and 1 to 30% of any one of non-sizing carbon fiber or carbon fiber sized with a sizing agent It is made by mixing 5 to 20 parts by weight of maleic anhydride grafted polyethylene with maleic anhydride added to 100 parts by weight of polyethylene resin containing%.

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Here, the carbon fiber is characterized by using a non-sizing carbon fiber or a carbon fiber sized with a sizing agent.

Here, the sizing agent is characterized in that the one selected from the group consisting of uretan resin, epoxy resin, nylon resin.

Here, the carbon fiber is characterized in that the epoxy sizing carbon fiber sized with an epoxy resin.

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Here, the carbon fiber is characterized in using a chopped type or a milled type.

Here, 1 to 10 parts by weight of a reinforcing agent selected from the group consisting of methyl methacrylate-butadiene-styrene reinforcing agent, acrylic reinforcing agent, chlorinated polyethylene reinforcing agent (CPE) reinforcing agent is further added to 100 parts by weight of the polyethylene resin composition. It is done.

In the present invention, the carbon of any one of 70 to 99% by weight of the high-density polyethylene resin having an average density of 0.941 ~ 0.965g / ml, and carbon fiber sized with a non-sizing carbon fiber or a sizing agent 5 to 20 parts by weight of maleic anhydride grafted polyethylene added with maleic anhydride to 100 parts by weight of the mixture, and mixed with 1 to 30% by weight of fibers. Preparing a kneaded polyethylene resin composition by mixing into a mixer;

Drying the kneaded polyethylene resin composition for 20 to 30 hours and extruding it at 210 to 250 ° C. using a twin screw extruder, followed by grinding and processing into pellets;
A secondary pellet processing step of repeatedly extruding the processed pellets in the same condition to process the pellets;

Melting the processed pellets at 180 to 195 ° C., and co-extruding the melted melt at a rate of 250 to 340 kg / h to form a tube; And

It provides a polyethylene resin water and sewage pipe manufacturing method comprising the step of cooling the molded tube to 14 ~ 18 ℃.

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The polyethylene resin composition of the present invention mixes a chopped type or milled type epoxy sized carbon sized or nonsized carbon fiber with a high density polyethylene resin and improves the dispersibility of the carbon fiber in the mixture. By adding a surfactant additive, the mechanical properties of the polyethylene resin can be improved, thereby producing a large pipe such as a water and sewage pipe.

Hereinafter, the present invention will be described in more detail.

The PE described below refers to polyethylene.

In order to improve the mechanical properties of PE, PE pipes are made of carbon black and glass fiber as reinforcing materials, but they show environmental problems and insufficient physical properties. PE pipes using carbon fiber have not been developed.

At present, PE pipe is manufactured using 2-3% carbon black to improve the weather resistance of PE when manufacturing PE pipe, but it cannot be sufficiently increased in strength. In addition, the FRP tube using glass fiber is also produced, but because of the environmental problems caused by the glass fiber and the problem of joining the tube, the present inventors have developed the present invention to develop a PE tube using carbon fiber (hereinafter referred to as) Completed.

Deformation problem occurs when applying the polyethylene (PE) pipe with the best physical properties as a water supply pipe. Therefore, by reinforcing the PE pipe with high rigid carbon fiber, the pipe deformation problem is solved and developed. It is intended to complete the present invention for the purpose.

In general, carbon fiber is injected into a cylindrical nozzle that heats an organic fiber, which is a material of the fiber, and extracts it into a fine thread shape. agent). At this time, the sizing agent is urethane, epoxy, nylon and the like.

Here, the method of processing with the sizing agent applies a conventional sizing process.

In the present invention, the carbon fiber used is a carbon fiber sized with the sizing agent and a non-sizing carbon fiber, and high density polyethylene resin (HDPE) is used as the PE resin. .

At the same time, recognizing the importance of adhesion between CF and HDPE resin interface, in order to further improve interfacial adhesion between fiber and resin, surfactant additives are added as additives to induce high interfacial adhesion between fiber and resin. Development was carried out for the purpose of realizing the excellent mechanical properties of the carbon fiber with the excellent performance of the pipe when manufacturing the PE pipe.

The polyethylene resin composition according to the present invention is made by mixing 5 to 20 parts by weight of the surfactant additive with respect to 100 parts by weight of the polyethylene resin including 70 to 99% by weight of the high density polyethylene resin and 1 to 30% by weight of the carbon fiber.

It is preferable to use a resin having an average density of 0.941 to 0.965 of the high density polyethylene resin. It is also possible to form a water pipe using a low density polyethylene resin or a medium density polyethylene resin having a density lower than the above density, but in order to have a more suitable strength as a water pipe, it is necessary to use a high density polyethylene resin having the above density. More suitable and preferred.

The carbon fiber is preferably a non-sizing carbon fiber or a carbon fiber sized with a sizing agent. In addition, the carbon fiber is more preferably used to have a length of 2 ~ 8mm in order to secure the adhesion and dispersibility with the resin. More preferably, it is more preferable to use 3 to 6 mm carbon fiber.

As the sizing agent, one selected from the group consisting of uretan resin, epoxy resin and nylon resin may be used, and more preferably, urethane resin may be used, and therefore, more preferably, epoxy sizing with the epoxy resin. (Epoxy sizing) carbon fiber is recommended.

The surfactant may be a surfactant additive which is usually used for the purpose of enhancing the interfacial adhesion between the resin and the fiber, so long as it is not impaired in the physical property change of the PE resin desired in the present invention, more preferably It is better to use maleic anhydride grafted polyethylene with the addition of maleic anhydride.

According to the present invention, the carbon fiber can be used by processing into a chopped type or a milled type.

According to the present invention, the reinforcing agent selected from the group consisting of methyl methacrylate-butadiene-styrene reinforcing agent, acryl-based reinforcing agent, and chlorinated polyethylene-based (CPE) reinforcing agent based on 100 parts by weight of the polyethylene resin composition of the present invention disclosed above. 10 parts by weight may be further added.

According to the present invention, there is provided a method for producing a water and sewage pipe made of a polyethylene resin material using the polyethylene resin composition disclosed above.

The manufacturing method is mixed to include 70 to 99% by weight of the high-density polyethylene resin and 1 to 30% by weight of carbon fiber, maleic anhydride (maleic anhydride) added to 100 parts by weight of the mixture Preparing a kneaded polyethylene resin composition by mixing 5 to 20 parts by weight of a maleic anhydride grafted polyethylene in a mixer; and drying the kneaded polyethylene resin composition for 20 to 30 hours using a twin screw extruder. Extruded at 210 to 250 ° C., and then pulverized and processed into pellets; and the processed pellets are melted at 180 to 195 ° C., and the molten melt is cooled at a rate of 250 to 340 kg / h. Extruding to form a tube; And cooling the molded tube to 14 to 18 ° C.

According to the present invention, it is more preferable that the pellets processed in the step of processing the pellets are repeatedly carried out two or more times in the step of repeatedly extruding the same conditions to process the pellets.

The physical properties of the polyethylene resin composition of the present invention disclosed above were measured through experiments, and the measuring method is as described below.

The embodiments disclosed below are examples of the polyethylene resin composition provided by the present invention, and are not intended to limit the present invention to the following examples, and the composition ratios thereof may be changed as necessary.

[Example]

<Preparation of materials>

As polyethylene resin, high density polyethylene resin (HDPE) having an average density of 0.941 ~ 0.951g / ml was used, and carbon fiber was used as sizing with epoxy resin and non-sizing carbon fiber.

Maleic anhydride grafted polyethylene (PE-g-MA) was used to increase the interfacial bond between resin and fiber.

<Testing Method>

1. HDPE, carbon fiber and additives were dried for 24 hours, extruded at 230 using a twin screw extruder, and then ground to pellets. The pellet was molded at 230 using a molder and then cooled to prepare specimens of a dumbbell type and a Rectangular type.

2. When the specimen is manufactured, the pellets prepared before molding with a molder are dried for 24 hours, extruded at 230 ° C. using a twin screw extruder, and then pulverized to make pellets. The specimen was prepared by the method.

<Method analysis method>

1. Tensile Strength and Tensile Modulus

Dumbbell-type specimens were used in a universal testing machine (UTM), and the test speed was measured at 50 mm / min.

2. Flexural Strength and Flexural Modulus

In the UTM, a Reeggler type specimen was used and measured at a test speed of 10 mm / min.

<Experimental Results>

1. Result of using chopped type and milled type epoxy-sizing carbon fiber

Two mechanically added specimens of chopped type and milled type of epoxy-sizing carbon fibers were prepared and their mechanical properties were measured.

1) Measurement result of physical properties of HDPE / CF (milled type)

When 1, 3, 5, and 10% by weight of milled type carbon fiber is added, the change in physical properties is increased with increasing amount of carbon fiber, as shown in Table 1 below. Confirmed that it is not large.

2) Measurement result of HDPE / CF (chopped type)

In the following Table 2, when the chopped type carbon fiber is added, physical properties increase as the amount added increases.

Tensile strength and flexural strength were increased when carbon fiber was added, and it was confirmed that a great increase was made in 10% of flexural strength and flexural modulus.

As a result of Tables 1 and 2, it was confirmed that the chopped type of the carbon fiber has better mechanical properties than the milled type. Therefore, in the subsequent experiment, the specimen was manufactured by using the carbon fiber of the chopped type as the carbon fiber. Physical properties were measured.

2. Measurement of physical property change when adding epoxy-sizing carbon fiber and non-sizing carbon fiber

The change of mechanical properties was measured when carbon fiber was added with sizing with epoxy and non-sizing.

1) Measurement results of HDPE / CF (chopped type and epoxy-sizing)

As shown in Table 3, the tensile and flexural strengths of the chopped type and epoxy-sized carbon fiber when 1, 3, and 5% were added gradually increased, but increased rapidly when added more than 10%, especially the flexural modulus. Has increased significantly at 20%.

2) Measurement results of physical properties of HDPE / CF (chopped type and epoxy-sizing, 2 pass)

In order to more effectively disperse CF in the polymer matrix and improve mechanical properties, two repeated two-extrusion experiments were performed, in which carbon fiber was added and extrusion was performed again. As a result, it was confirmed that the results of Table 4, which are the physical properties of the specimens produced by the extrusion process twice, are almost the same as those of Table 3, the results of the specimens extruded only once.

3) Measurement results of HDPE / CF (chopped type and non-sizing)

Experiments were conducted to see the properties of non-sized CF. Since non-sizing CF contained moisture, it went through the drying process before the experiment, and it was difficult to input during extrusion because the carbon fiber was released as the moisture evaporated. Therefore, it extruded without drying, but it was judged that some moisture evaporated by heat at the time of extrusion. As shown in Table 5 below, the tensile strength was increased compared to the epoxy sized CF, but the tensile modulus decreased, but it increased rapidly from 20% or more, and the flexural modulus decreased compared to the epoxy sizing CF. I could see that.

In view of the change in tensile modulus of elasticity, it is considered that there is an influence of moisture contained in CF.

4) Measurement results of physical properties of HDPE / CF (chopped type and non-sizing, 2 pass)

In the previous experiment, it was judged that there was no effect of drying the perfect moisture in one processing process, and repeated drying extrusion process under the same conditions was attempted to dry the complete moisture.

As a result, as shown in Table 6, it can be seen that the mechanical properties of each were significantly increased compared with the case of one extrusion. This is believed to be the result of complete evaporation of the water contained in the carbon fiber.

3. Property evaluation after adding additive

The addition of additives to strengthen the interface between the carbon fiber and polyethylene resin is thought to be possible to increase the physical properties was carried out experiments to simultaneously add the additives during extrusion. As an additive, modified polyethylene (PE-g-MA) added with maleic anhydride was determined to be optimal.

1) Measurement results of HDPE / CF (chopped type and non-sizing) / PE-g-MA

To further improve the interfacial adhesion between HDPE and CF, 5 parts by weight (Table 7) and 10 parts by weight (Table 8) of maleic anhydride grafted polyethylene (PE-g-MA) per 100 parts by weight of HDPE / CF mixture Experiments were performed.

When using non-sizing CF as shown in Tables 7 and 8 it can be seen that the mechanical properties are significantly increased compared to the case without using the carbon fiber than when the additive is not used.

2) Measurement results of physical properties of HDPE / CF (chopped type and epoxy-sizing) / PE-g-MA

Epoxy-sizing CF enhances the adhesion between the interface between carbon fiber and HDPE resin when co-extrusion with additive (PE-g-MA). Table 9 (add 5 parts by weight of additive), 10 (add 10 parts by weight of additive) It can be seen that the physical properties increase as shown in (11, 15 parts by weight of the additive), 12 (20 parts by weight of the additive).

As a result, the addition of only 5 parts by weight of the additive shows a sufficient increase in physical properties, and even after increasing the amount of the additive was found that the degree of increase in physical properties does not change significantly. Particularly, when 20 parts by weight was added, the physical properties increased, but less than 20 parts by weight was added.

As a result, it is judged that addition of 5 parts by weight of additives is optimal in terms of physical properties and economics.

In particular, the physical properties at this time is superior to the results for the other experiments conducted earlier, it was determined that it is best to use PE-g-MA as the epoxy sized carbon fiber and additives.

As a result of the experiment shown above, two physical properties of milled type and chopped type were confirmed through the experiment to compare the difference of physical properties according to the shape of carbon fiber. In the case of milled type, the purpose of the present invention could be achieved in the process of experimenting, but one disadvantage was that there were difficulties in process such as mixing, and it was difficult to evenly disperse the carbon fibers in the polymer matrix. Could know. On the other hand, the chopped type carbon fiber had better dispersibility than the milled type carbon fiber, and thus the mechanical properties were superior to the milled type. Therefore, it was confirmed that the mechanical properties are increased when mixing the carbon fiber, more preferably, it is better to use the chopped type carbon fiber than the carbon fiber miiiled type.

In the manufacture of carbon fiber, the removal of water is required in the case of non-sizing carbon fiber in the process of comparing and checking the physical properties when it is mixed with polyethylene resin with epoxy sized product and not sized water treatment. After drying, it was applied to the process, but the water-removed carbon fiber was not evenly fed when it was put into the extruder, so extrusion was not easy.

On the basis of this reason, the drying process was omitted and directly added to the extruder to induce the drying of moisture by the heat of processing and to compare the mechanical properties of the carbon fiber with conventional epoxy sizing. As a result, it can be seen that the mechanical properties are superior to the world without the carbon fiber, and the level slightly less than the results of the epoxy sized samples.

This was judged to be because the complete moisture was not dried in one extrusion process. As a result of extruding the non-sized carbon fiber in the 2 pass process, the increase in mechanical properties was confirmed.

In order to further improve the adhesion between the interface between the carbon fiber and the HDPE resin to further improve the physical properties, PE-g-MA as an additive was used as an additive. It was found that the mechanical properties were greatly increased due to the excellent interfacial adhesion. In particular, when the epoxy sized carbon fiber is used, the mechanical properties were greatly increased, and the increase in physical properties was not significantly improved in the non-sizing carbon fiber.

As a result, it was found that the mechanical properties were greatly increased by the addition of additives, and in particular, when the epoxy sizing carbon fiber was used and the content of PE-g-MA was 5 parts by weight, it was observed that optimum properties were obtained.

Claims (10)

In the polyethylene resin composition for water and sewage pipe production,
70 to 99% by weight of a high density polyethylene resin having an average density of 0.941 to 0.965 g / ml, and 1 to 30% of any one of non-sizing carbon fiber or carbon fiber sized with a sizing agent Polyethylene resin, characterized in that 5 to 20 parts by weight of maleic anhydride grafted polyethylene (maleic anhydride) is added to 100 parts by weight of polyethylene resin containing% Resin composition. delete delete The method of claim 1,
The sizing agent is a polyethylene resin composition, characterized in that one selected from the group consisting of uretan resin, epoxy resin, nilo resin. The method of claim 1,
The carbon fiber is a polyethylene resin composition, characterized in that the epoxy sizing carbon fiber sized with an epoxy resin. delete The method of claim 1,
The carbon fiber is a polyethylene resin composition, characterized in that using a chopped type (milled type). The method of claim 1,
1 to 10 parts by weight of a reinforcing agent selected from the group consisting of methyl methacrylate-butadiene-styrene reinforcing agent, acryl reinforcing agent and chlorinated polyethylene reinforcing agent (CPE) reinforcing agent is further added to 100 parts by weight of the polyethylene resin composition. Polyethylene resin composition. In the polyethylene resin water and sewage pipe manufacturing method,
70 to 99% by weight of the high-density polyethylene resin and 1 to 30% by weight of carbon fiber, and mixed with maleic anhydride graft polyethylene (maleic anhydride) added to 100 parts by weight of the mixture ( Maleic anhydride grafted polyethylene) 5 to 20 parts by weight of a blender to prepare a kneaded polyethylene resin composition;
Drying the kneaded polyethylene resin composition for 20 to 30 hours and extruding it at 210 to 250 ° C. using a twin screw extruder, followed by grinding and processing into pellets;
A secondary processing step of repeatedly extruding the processed pellets under the same conditions to process the pellets;
Melting the processed pellets at 180 to 195 ° C., and co-extrusion the melted melt at a rate of 250 to 340 kg / h to form a tube; And
Polyethylene resin water and sewage pipe manufacturing method comprising the step of cooling the molded tube to 14 ~ 18 ℃. delete