CN115011019A

CN115011019A - High-strength PE gas pipe and preparation method thereof

Info

Publication number: CN115011019A
Application number: CN202210719205.XA
Authority: CN
Inventors: 孙瀚中; 崔东明; 闫明风
Original assignee: Qingdao U Pipe Environmental Protection Technology Co ltd
Current assignee: Qingdao U Pipe Environmental Protection Technology Co ltd
Priority date: 2022-06-23
Filing date: 2022-06-23
Publication date: 2022-09-06
Anticipated expiration: 2042-06-23
Also published as: CN115011019B

Abstract

The application relates to the field of plastic pipes, and particularly discloses a high-strength PE gas pipe and a preparation method thereof. A high-strength PE gas pipe comprises the following raw materials in parts by weight: 100 parts of high-density polyethylene resin, 6.5-9.5 parts of carbon black master batch and 0.5-2 parts of antioxidant; the carbon black master batch is prepared from high-density polyethylene resin, carbon black, mica powder and polytetrafluoroethylene powder in a weight ratio of 15:8-12:4-6: 1-3; the carbon black is subjected to dispersion treatment before use, and then is subjected to treatment of a silane coupling agent and polyvinyl alcohol to obtain the pretreated carbon black. The carbon black is added in the form of master batch, and mica powder and polytetrafluoroethylene powder are added at the same time, so that the water absorption of the carbon black can be reduced, and the appearance defect of a product caused by water absorption is improved.

Description

High-strength PE gas pipe and preparation method thereof

Technical Field

The application relates to the field of plastic pipes, in particular to a high-strength PE gas pipe and a preparation method thereof.

Background

The gas pipe is a special pipeline for conveying combustible gas, and the traditional gas pipe is mainly made of metal materials; in recent years, with the development of technology, plastic gas pipes are gradually replacing traditional metal gas pipes, and most of the existing plastic gas pipes are PE gas pipes.

The raw materials of the PE gas pipe generally comprise PE resin, pigment, functional auxiliary agent and the like; at present, carbon black is mostly used as pigment for the PE gas pipe, and the PE gas pipe has the advantages of low cost and good ultraviolet resistance. However, carbon black has a relatively large specific surface area, and thus has high water absorption. In the process of extruding and plasticizing the PE gas pipe, moisture absorbed in carbon black can be vaporized at high temperature, and after the PE gas pipe is extruded out of a die, as the pressure of extruded melt is not available, the vaporized 'water bubbles' form pits and sharkskin symptoms on the surface and inside of a pipeline product, so that the appearance of the product is influenced, and the quality of the product is also influenced. In order to reduce the above influence, in the production of pipelines, the granules need to be dried first to reduce the influence of moisture on the processing of the product. However, after the pipeline is produced, due to the existence of carbon black, the pipeline still absorbs water vapor in the air to form surface adsorbed moisture and combined moisture, and in the subsequent welding process, defects such as bubbles and pinholes still occur at the welding interface, so that the mechanical strength of the product is affected.

Disclosure of Invention

In order to solve the problems, the application provides a high-strength PE gas pipe and a preparation method thereof.

In a first aspect, the present application provides a high strength PE gas pipe, which adopts the following technical scheme:

a high-strength PE gas pipe comprises the following raw materials in parts by weight: 100 parts of high-density polyethylene resin, 6.5-9.5 parts of carbon black master batch and 0.5-2 parts of antioxidant;

the carbon black master batch is prepared from high-density polyethylene resin, carbon black, mica powder and polytetrafluoroethylene powder in a weight ratio of 15:8-12:4-6: 1-3.

Due to the existence of carbon black, in the process of preparing the pipe and the subsequent welding process, defects such as bubbles, pinholes and the like can be generated on the surface, the inside and the welding interface of the pipe due to the absorption of water in the air, so that the product quality is influenced. In addition, because the gas pipe is used for conveying gas, the risk is high, so the dispersion uniformity of carbon black and an auxiliary agent in polyethylene base resin needs to be ensured, and the specific surface energy of the carbon black is high, so that agglomeration is easy to occur in the polyethylene resin, and the processing is difficult. Therefore, the performance of carbon black has a great influence on the mechanical strength and appearance quality of the gas pipe. By adopting the technical scheme, the carbon black is added in the form of the master batch, and the mica powder and the polytetrafluoroethylene powder are added at the same time, so that the dispersity of the carbon black in the polyethylene resin can be improved, and the processability is improved. Meanwhile, before the carbon black is used, the surface treatment of the silane coupling agent is carried out, so that the dispersibility of the carbon black in the polyethylene resin can be improved; and then, the surface of the carbon black can be coated with a film by treating the aqueous solution of the polyvinyl alcohol so as to reduce the water absorption of the carbon black, thereby reducing the appearance defect and the welding performance of the product caused by the water absorption of the carbon black.

Preferably, the carbon black: silane coupling agent: the weight ratio of the polyvinyl alcohol is 30:0.4-0.8: 0.5-1.5.

Preferably, the carbon black master batch is prepared by the following method:

mixing and stirring high-density polyethylene resin, carbon black, mica powder and polytetrafluoroethylene powder to obtain a mixture;

and melting, extruding and granulating the mixture at the temperature of 160-180 ℃ to obtain the carbon black master batch.

By adopting the technical scheme, the high-density polyethylene resin is used as the carrier resin of the carbon black, so that the mixing uniformity of the carbon black master batch in the matrix resin of the gas pipe is ensured, and the stability of the quality of the gas pipe is favorably improved.

Preferably, the carbon black has an average particle diameter of 10nm to 40 nm.

The carbon black can be used as a pigment, and can improve the ultraviolet resistance and weather resistance of the material; the smaller the particle size of the carbon black, the better the ultraviolet light absorbing ability thereof. By adopting the technical scheme, the carbon black with the particle size of 10-40nm is adopted, so that the mechanical property of the product can be improved, and the weather resistance of the product can also be improved.

Preferably, the mica powder is pretreated before use by the following method:

placing mica powder in acid liquor, and stirring for 1-2h to obtain acid-treated mica powder;

calcining the acid-treated mica powder at the temperature of 300-400 ℃ for 3-5h to obtain calcined mica powder;

adding water and oil-acyl diethanolamine into calcined mica powder, stirring uniformly, adding a silane coupling agent, and stirring for reacting for 1-2 h; and drying to obtain the pretreated mica powder.

The mica powder has good wear resistance and strength, and the size stability of the product can be improved; the mica powder can replace part of carbon black, so that the performance of the product can be kept from being damaged, and the cost of the product is reduced; in addition, compared with carbon black, the mica powder has low water absorption, and the water absorption of the product can be further reduced. By adopting the technical scheme, the mica powder is treated by the acid liquor and then calcined, so that impurities in the mica powder can be removed; then the mica powder is treated by respectively adopting the oil-acyl diethanolamine and the silane coupling agent, a hydrophobic film with good hydrophobic effect can be formed on the surface of the mica powder, the dispersibility of the hydrophobic film in the polyethylene resin can be improved, the water absorption of the filler can be reduced, and the quality defect of the gas pipe can be improved.

Preferably, the antioxidant consists of the antioxidant 1010 and the antioxidant 168 in a weight ratio of 1: 1.

By adopting the technical scheme, the antioxidant 1010 and the antioxidant 168 have good synergistic effect, so that the thermal stability of the product in the processing process can be improved, the thermal oxidation degradation of the product is reduced, and the service life of the product can be effectively prolonged.

In a second aspect, the present application provides a method for preparing a PE gas pipe, which adopts the following technical scheme:

a preparation method of a high-strength PE gas pipe comprises the following steps:

s1, preparing a mixed material: uniformly mixing high-density polyethylene resin and carbon black master batch with an antioxidant according to a ratio, putting the mixture into a double-screw extruder, and performing melting, extrusion and granulation to obtain a mixed material;

s2, feeding and drying: drying the mixed material of S1 until the water content is less than or equal to 200mg/kg for later use;

s3, plasticizing and extruding: putting the dried mixed material of S2 into a single-screw extruder, and performing extrusion molding to obtain a pipe;

s4, vacuum forming: and (3) carrying out vacuum shaping, cooling, traction cutting on the pipe to obtain the PE gas pipe.

Preferably, the temperature of each zone of the twin-screw extruder in S1 is set as follows: the first zone is at a temperature of 140-.

Preferably, the drying temperature in the S2 is 80-90 ℃, and the drying time is 3-5 h.

By adopting the technical scheme, in order to reduce the influence of the water absorption of the carbon black, the mixed material is dried for 3-5 hours at the temperature of 80-90 ℃, which is beneficial to improving the stability of the product.

Preferably, the barrel temperature of the single-screw extruder in S3 is 180-220 ℃, and the die orifice temperature is 180-225 ℃.

Preferably, the vacuum degree of the vacuum forming in the S4 is 0.02-0.07 MPa.

By adopting the technical scheme, the vacuum degree of the vacuum forming device is set to be 0.02-0.07MPa, so that the appearance quality of the pipe can be met, the internal stress of the pipe can be reduced, and the deformation of the product in the storage process can be reduced.

In summary, the present application has the following beneficial effects:

1. according to the application, the carbon black is added in the form of master batch, and the mica powder and the polytetrafluoroethylene powder are added at the same time, so that the dispersibility of the carbon black in the polyethylene resin can be improved, and the processability is improved. Meanwhile, before the carbon black is used, the surface treatment of the silane coupling agent is carried out, so that the dispersibility of the carbon black in the polyethylene resin can be improved; and then, the surface of the carbon black can be coated with a film by treating the aqueous solution of the polyvinyl alcohol so as to reduce the water absorption of the carbon black, thereby reducing the appearance defect and the welding performance of the product caused by the water absorption of the carbon black.

2. According to the application, the optimized mica powder is treated by respectively adopting the oleoyl diethanol amine and the silane coupling agent before use, so that a hydrophobic film with a good hydrophobic effect can be formed on the surface of the mica powder, the dispersibility of the mica powder in the polyethylene resin can be improved, the water absorption of the filler can be reduced, and the quality defect of a gas pipe can be improved.

Detailed Description

The present application will be described in further detail with reference to examples.

Preparation example of carbon Black masterbatch

The starting materials in the examples are all commercially available, unless otherwise specified. Wherein the high density polyethylene resin is TR480M, and the density is 0.9,44g/cm ³ The melt index (190 ℃/5kg) is 0.5g/10 min; selecting carbon black N330 as carbon black, wherein the average particle size is 20 nm; the silane coupling agent is a silane coupling agent KH 550; the mica powder is muscovite powder with fineness of 200 meshes.

Preparation example 1

(1) Pretreatment of carbon black: adding carbon black into absolute ethyl alcohol, and performing ultrasonic dispersion for 35min to obtain 30 wt% of carbon black dispersion liquid;

adding 0.05kg of silane coupling agent into 10kg of carbon black dispersion liquid, carrying out ultrasonic dispersion for 1.5h, adding 0.5kg of 20 wt% polyvinyl alcohol aqueous solution, and carrying out ultrasonic dispersion for 1.5 h; then evaporating the solvent at the temperature of 80 ℃ and under the pressure of-0.9 MPa; and drying for 4 hours at the temperature of 80 ℃ to obtain the pretreated carbon black.

(2) Preparation of carbon black master batch: taking 1.5kg of high-density polyethylene resin, 0.8kg of pretreated carbon black, 0.4kg of mica powder and 0.1kg of polytetrafluoroethylene powder, and stirring and mixing at the speed of 200r/min for 30min to obtain a mixture;

putting the mixture into a double-screw extruder, and setting the temperature of each area of the double-screw extruder as follows: the carbon black master batch is obtained by melting, extruding and granulating at the temperature of 160 ℃ in the first zone, 165 ℃ in the second zone, 170 ℃ in the third zone, 180 ℃ in the fourth zone, 180 ℃ in the fifth zone, 170 ℃ in the sixth zone, 170 ℃ in the seventh zone and 175 ℃ in the die orifice.

Preparation example 2

The difference between the preparation example and the preparation example 1 is that in the step (2), the dosage of the pretreatment carbon black is 1.2kg, the dosage of the mica powder is 0.6kg, and the dosage of the polytetrafluoroethylene powder is 0.3 kg.

Preparation example 3

The difference between the preparation example and the preparation example 1 is that the mica powder is treated by the following method before use:

firstly, placing mica powder in 10 wt% hydrochloric acid solution, stirring for 2h, and carrying out solid-liquid separation to obtain acid-treated mica powder;

② calcining the acid-treated mica powder at 350 ℃ for 4h to obtain calcined mica powder;

thirdly, adding 5kg of water and 0.05kg of oleic diethanol amine into 1kg of calcined mica powder, uniformly stirring, adding 0.05kg of silane coupling agent, and stirring and reacting for 1 hour at the temperature of 80 ℃; then drying the mixture at the temperature of 80 ℃ for 6 hours to obtain the pretreated mica powder.

Preparation example 4

The difference between the preparation example and the preparation example 1 is that mica powder and polytetrafluoroethylene powder are not added in the step (2).

Preparation example 5

This production example is different from production example 1 in that the carbon black was not subjected to the pretreatment of step (1) before use.

Examples

The starting materials in the examples are all commercially available, unless otherwise specified. Wherein the high density polyethylene resin is TR480M, and the density is 0.944g/cm ³ The melt index (190 ℃/5kg) is 0.5g/10 min; the antioxidant consists of antioxidant 1010 and antioxidant 168 in a weight ratio of 1: 1.

Examples 1 to 5

As shown in Table 1, examples 1-5 differ primarily in the amount and source of the starting materials. In the following, example 1 is taken as an example to illustrate the preparation method of the high-strength PE gas pipe provided in example 1, which is as follows:

s1, preparing a mixed material: mixing HDPE and carbon black master batch uniformly by using antioxidant according to a ratio, putting into a double-screw extruder, and setting the temperature of each area of the double-screw extruder as follows: 145 ℃ in the first zone, 155 ℃ in the second zone, 165 ℃ in the third zone, 175 ℃ in the fourth zone, 185 ℃ in the fifth zone, 185 ℃ in the sixth zone, 175 ℃ in the seventh zone and 175 ℃ in the die orifice; after melting, extruding and granulating, the mixed material is obtained;

s2, feeding and drying: drying the mixed material of S1 at 85 deg.C for 3h to make its water content less than or equal to 200 mg/kg;

s3, plasticizing and extruding: and (3) putting the dried mixed material of S2 into a single-screw extruder, and setting the temperature of each area of the single-screw extruder as follows: extruding and forming to obtain a pipe, wherein the temperature of a first zone is 180 ℃, the temperature of a second zone is 185 ℃, the temperature of a third zone is 190 ℃, the temperature of a fourth zone is 200 ℃, the temperature of a fifth zone is 210 ℃, the temperature of a sixth zone is 220 ℃, and the temperature of a die orifice is 220 ℃;

s4, vacuum forming: vacuum forming the pipe under the condition that the vacuum degree is 0.04 MPa; then cooling the pipe by adopting a spray cooling mode; and finally, after traction and cutting, starting the color bar co-extruder to obtain the gas pipe with the yellow bars uniformly distributed along the circumferential direction of the pipe.

TABLE 1 raw material consumption Scale (unit: kg) for examples 1-5

Comparative example

Comparative example 1

This comparative example differs from example 1 in that a carbon black masterbatch was prepared by preparation example 4 of a carbon black masterbatch.

Comparative example 2

This comparative example differs from example 1 in that a carbon black masterbatch was prepared by preparation example 5 of a carbon black masterbatch.

Performance test

Gas pipes having the same inner and outer diameters were prepared by the methods of examples 1 to 5 and comparative examples 1 to 2, and their properties were measured as follows, and the results are shown in table 2.

1. Appearance: placing the pipe in an environment with the temperature of 25 ℃ and the relative humidity of 85% RH for 14 d; then heating the pipe for 15min at the welding temperature of 220 ℃, cutting the pipe after cooling, and obtaining the condition of bubbles and pinholes on the internal section of the pipe; if the number of the needle holes on the cross section is less than 5, marking as 'A'; if the number of the needle holes on the cross section is 5-15, marking as 'B'; if the number of the needle holes on the cross section is more than 15, the mark is 'C'.

2. Mechanical properties: according to GB/T15558.1-2015 buried Polyethylene (PE) pipeline system for fuel gas part 1: pipe material method the mechanical properties of the PE gas pipes produced in examples 1-5 and comparative examples 1-2 were tested.

TABLE 2 Performance test Table for PE gas pipes of examples 1 to 5 and comparative examples 1 to 2

By combining the example 1, the comparative example 1 and the comparative example 2 and combining the table 2, the pipe material of the example 1 has better appearance quality and mechanical strength, the carbon black dispersion degree is high, and the product has good performance stability. The carbon black is added in the form of master batch, and the high-density polyethylene resin which is the same as the matrix resin of the pipe is used as a carrier, so that the dispersion degree of the carbon black in the matrix resin of the pipe can be improved. In addition, when the carbon black master batch is prepared, the carbon black is pretreated firstly, so that the dispersibility of the carbon black in resin can be improved; the mica powder and the polytetrafluoroethylene powder are added to improve the dispersibility of the carbon black in the resin, replace a part of the carbon black to reinforce the pipe, and reduce the appearance defect of the pipe caused by high water absorption of the carbon black. The welding material prepared by the embodiment 1 has good appearance quality, low water absorption rate in a humid environment, and good welding quality, and is not easy to generate defects such as bubbles and pinholes during welding processing.

Combining example 1 and example 5 and table 2, it can be seen that the mechanical properties of the pipe of example 5 are significantly better than those of example 1, because the mica powder can be improved in dispersibility in resin after being pretreated before use, thereby improving the mechanical properties of the product.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. A high-strength PE gas pipe is characterized by comprising the following raw materials in parts by weight: 100 parts of high-density polyethylene resin, 6.5-9.5 parts of carbon black master batch and 0.5-2 parts of antioxidant;

the carbon black master batch is prepared from high-density polyethylene resin, carbon black, mica powder and polytetrafluoroethylene powder in a weight ratio of 15:8-12:4-6: 1-3;

the carbon black is pretreated by the following method before use:

adding carbon black into absolute ethyl alcohol, and performing ultrasonic dispersion for 30-40min to obtain a carbon black dispersion liquid;

adding a silane coupling agent into the carbon black dispersion liquid, performing ultrasonic dispersion for 1-2h, adding a polyvinyl alcohol aqueous solution, and performing ultrasonic dispersion for 1-2 h; then evaporating the solvent, and drying to obtain the pretreated carbon black.

2. The high strength PE gas pipe as claimed in claim 1, wherein the carbon black: silane coupling agent: the weight ratio of the polyvinyl alcohol is 30:0.4-0.8: 0.5-1.5.

3. The high-strength PE gas pipe as claimed in claim 1, wherein the carbon black master batch is prepared by the following method:

4. The high-strength PE gas pipe as claimed in claim 1, wherein the mica powder is pre-treated before use by the following method:

adding water and 0.4-0.8 part by weight of oleic diethanol amide into 10 parts by weight of calcined mica powder, uniformly stirring, adding 0.4-0.8 part by weight of silane coupling agent, and stirring and reacting at the temperature of 70-85 ℃ for 1-2 hours; and drying to obtain the pretreated mica powder.

5. The high-strength PE gas pipe as claimed in claim 1, wherein the antioxidant consists of the antioxidant 1010 and the antioxidant 168 in a weight ratio of 1: 1.

6. The method for preparing a high-strength PE gas pipe as claimed in claim 1, comprising the steps of:

7. The method for preparing a high-strength PE gas pipe as claimed in claim 6, wherein the temperature of each zone of the twin-screw extruder in S1 is set as follows: the first zone is at a temperature of 140-.

8. The method for preparing a high-strength PE gas pipe as claimed in claim 6, wherein the drying temperature in S2 is 80-90 ℃ and the drying time is 3-5 h.

9. The method for preparing a high-strength PE fuel gas pipe as claimed in claim 6, wherein the barrel temperature of the single-screw extruder in S3 is 180-220 ℃ and the die orifice temperature is set to 180-225 ℃.

10. The method for preparing a high-strength PE gas pipe according to claim 6, wherein the vacuum degree of vacuum shaping in S4 is 0.02-0.07 MPa.