A high-speed extrusion anti-scale PE-RT floor heating pipe and preparation method thereof

Abstract

The present invention discloses a high-speed extrusion type anti-fouling PE-RT floor heating pipe and a preparation method thereof, and relates to the field of pipes. Wherein, the floor heating pipe comprises a PE-RT inner layer, an adhesive layer and an oxygen-barrier outer layer, and the PE-RT inner layer comprises a raw material PE-RT resin, a heat stabilizer, a thermal conductive filler and an anti-fouling agent; wherein the anti-fouling agent comprises a double-ended epoxy polysiloxane, a polyester diol, a polyfluoroalkyl diol and a tertiary amine catalyst, and the molar sum of the polyester diol and the polyfluoroalkyl diol does not exceed the double-ended epoxy polysiloxane, and the amount of the tertiary amine catalyst is 1-5% of the weight sum of the polysiloxane, the polyester diol and the polyfluoroalkyl diol. The PE-RT inner layer in the present application has a small surface roughness and an oxygen-barrier effect, effectively reducing the thickness of the oxygen-barrier outer layer while obtaining excellent oxygen-barrier performance, and having little effect on the thermal conductivity of the floor heating pipe.

Description

Technical Field

[0001] The invention relates to the field of pipe materials, and in particular to a high-speed extrusion type anti-scaling PE-RT floor heating pipe and a preparation method thereof. Background Art

[0002] Heat-resistant polyethylene is a metallocene-catalyzed copolymer of ethylene and octene monomers, also known as PE-RT. It is often used to make floor heating pipes, that is, a type of pipe used as a low-temperature hot water circulation carrier in low-temperature hot water floor radiant heating systems.

[0003] At present, the common problem of PE-RT floor heating pipes during use is that after a period of use, the inner wall of the pipe is prone to mud or scale, resulting in a decrease in the heat exchange efficiency of the PE-RT floor heating pipe. Among them, the main reasons for the easy scaling of PE-RT floor heating pipes are the following two aspects: (1) There are impurities such as scale in the circulating water flow. When the inner surface roughness of the pipe is large, it is easy to accelerate the deposition of scale; (2) The oxygen barrier performance of the pipe is poor, and the dissolved oxygen content in the water is high, which is easy to promote the growth of bacteria, thereby generating a large amount of bacterial mud impurities.

[0004] Among them, PE-RT floor heating pipes usually include a PE-RT inner layer, an adhesive layer and an oxygen-barrier outer layer. The commonly used raw materials for the oxygen-barrier outer layer are ethylene-vinyl alcohol copolymer, the commonly used raw materials for the adhesive layer are maleic anhydride grafted polyethylene, and the raw materials used for the PE-RT inner layer are PE-RT resin, heat stabilizer, and thermal conductive filler. In order to improve the anti-scaling effect of floor heating pipes, related technologies generally start from improving the smoothness of the inner surface of the pipe or enhancing the oxygen barrier performance of the oxygen-barrier outer layer of the floor heating pipe. Among them, improving the oxygen barrier performance of the pipe generally starts from increasing the thickness of the oxygen-barrier outer layer of the ethylene-vinyl alcohol copolymer. The oxygen barrier performance of the pipe is closely related to the thickness of the oxygen-barrier outer layer. The thicker the oxygen-barrier outer layer, the better the oxygen barrier performance of the pipe. However, the thicker the oxygen-barrier outer layer, the lower the thermal conductivity of the pipe, so the oxygen-barrier outer layer should not be set too thick. Improving the smoothness of the inner surface of the pipe generally starts from modifying the PE-RT inner layer, for example, adding polysiloxane to the PE-RT inner layer to improve the extrusion performance of the PE-RT inner layer, thereby improving the surface quality of the PE-RT inner layer. However, when adding polysiloxane anti-scaling agent to modify the inner layer of PE-RT, the oxygen barrier performance of the pipe cannot be improved at the same time. Summary of the invention

[0005] In order to obtain a floor heating pipe with good anti-scale effect and little influence on thermal conductivity, the present application provides a high-speed extrusion anti-scale PE-RT floor heating pipe and a preparation method thereof.

[0006] In the first aspect, the present application provides a high-speed extruded anti-scale PE-RT floor heating pipe adopts the following technical solution: a high-speed extruded anti-scale PE-RT floor heating pipe, comprising a PE-RT inner layer, an adhesive layer and an oxygen-barrier outer layer, wherein the PE-RT inner layer comprises the following raw materials in parts by weight:

[0007] PE-RT resin: 100 parts

[0008] Heat stabilizer: 1-2 parts

[0009] Thermal conductive filler: 15-20 parts

[0010] Anti-scaling agent: 4-6 parts

[0011] The anti-fouling agent comprises a double-terminal epoxy polysiloxane, a polyester diol, a polyfluoroalkyl diol and a tertiary amine catalyst, wherein the molar ratio of the double-terminal epoxy polysiloxane, the polyester diol and the polyfluoroalkyl diol is 1:(0.1-0.9):(0.9-0.1); the molar sum of the polyester diol and the polyfluoroalkyl diol does not exceed that of the double-terminal epoxy polysiloxane, and the amount of the tertiary amine catalyst is 1-5% of the total weight of the double-terminal epoxy polysiloxane, the polyester diol and the polyfluoroalkyl diol.

[0012] By adopting the above technical scheme, double-ended epoxy polysiloxane and polyester diol and polyfluoroalkyl diol can undergo a ring-opening reaction under the catalysis of a tertiary amine catalyst, and the obtained anti-scaling agent has three different structures on the main molecular chain structure: polysiloxane, polyester and fluoroalkyl. When the anti-scaling agent is mixed with PE-RT resin, heat stabilizer and thermal conductive filler to prepare the PE-RT inner layer, a PE-RT inner layer with small surface roughness, high mechanical properties and oxygen barrier properties can be obtained. Among them, after the present application uses a specific anti-scaling agent to modify the PE-RT inner layer, it can improve the surface roughness of the PE-RT inner layer while improving the oxygen barrier properties of the PE-RT inner layer. According to statistics, conventional floor heating pipes need to be cleaned once every 2-3 years. After adopting the floor heating pipes of the present application, the cleaning frequency of the floor heating pipes is reduced to once every 8-10 years.

[0013] In addition, when the above raw materials are used to prepare the PE-RT inner layer, the thickness of the oxygen-barrier outer layer can be 0.3-1mm. Among them, when the thickness of the oxygen-barrier outer layer is 1mm, the decrease in the thermal conductivity of the floor heating pipe is within the range of 0.01-0.03W / mK, that is, the oxygen-barrier outer layer has little effect on the thermal conductivity of the floor heating pipe, and a floor heating pipe with good anti-scaling effect and little effect on thermal conductivity can be obtained.

[0014] Preferably, the molar ratio of the double-terminal epoxy polysiloxane, polyester diol and polyfluoroalkyl diol is 1:(0.3-0.5):(0.7-0.5).

[0015] By adopting the above technical solution, the oxygen barrier performance of the floor heating pipe is further improved, effectively hindering the penetration of oxygen.

[0016] Optionally, the degree of polymerization of the dual-terminal epoxy polysiloxane is 100-1500.

[0017] Preferably, the degree of polymerization of the dual-terminal epoxy polysiloxane is 500-1000.

[0018] By adopting the above technical solution, when the polymerization degree of the double-ended epoxy polysiloxane is 500-1000, the oxygen barrier performance of the pipe is further improved.

[0019] Optionally, the polyfluoroalkyl glycol is HO(CH2) m (CF2) n (CH2) m OH, wherein m=1-4, n=3-12.

[0020] Preferably, the polyfluoroalkyl glycol is HO(CH2) m (CF2) n (CH2) m OH, wherein m=1-2, n=7-8.

[0021] By adopting the above technical solution, the preferred polyfluoroalkyl glycol can not only further improve the surface smoothness of the pipe, making it difficult for precipitates to adhere to the inner wall of the pipe, but also further improve the mechanical properties of the pipe.

[0022] Optionally, the molecular weight of the polyester diol is 500-3000.

[0023] Preferably, the molecular weight of the polyester diol is 1000-2000.

[0024] By adopting the above technical solution, when the molecular weight of the polyester diol is 1000-2000, it is beneficial to further improve the mechanical properties and oxygen barrier properties of the pipe.

[0025] Optionally, the tertiary amine catalyst is selected from any one of triethylenediamine, N-alkylmorpholine, and bis(2-methyloxyethyl)ether, or a combination of several of them.

[0026] Optionally, the thermally conductive filler is selected from any one of silicon carbide, graphene, copper powder, iron powder, zinc oxide, aluminum oxide, boron nitride, and aluminum nitride, or a combination of several of them.

[0027] In the second aspect, the present application provides a method for preparing a high-speed extrusion anti-scaling PE-RT floor heating pipe using the following technical solution:

[0028] A method for preparing a high-speed extrusion anti-scaling PE-RT floor heating pipe comprises the following steps:

[0029] The polyester diol, the double-terminal epoxy polysiloxane and the polyfluoroalkyl diol are subjected to a ring-opening reaction under the catalytic action of a tertiary amine catalyst to obtain an anti-fouling agent;

[0030] Melting the raw materials of the oxygen barrier outer layer to obtain an outer layer melt;

[0031] Melting the raw material of the bonding layer to obtain a bonding layer melt;

[0032] The PE-RT resin, the heat stabilizer, the heat conductive filler and the anti-fouling agent are mixed and melted to obtain an inner layer melt;

[0033] A three-layer co-extrusion composite die is used to compositely extrude the outer layer melt, the adhesive layer melt and the inner layer melt, and then after vacuum sizing and cooling and shaping, the anti-scale PE-RT floor heating pipe is obtained; wherein, the temperature of the three-layer co-extrusion composite extrusion die is controlled between 200-250℃, and the extrusion speed is controlled at 35-40m / min.

[0034] The preparation method of the anti-scaling agent comprises the following steps:

[0035] Add polyester diol, tertiary amine catalyst and double-terminal epoxy polysiloxane to n-propanol, the weight ratio of n-propanol to double-terminal epoxy polysiloxane is (45-60):1, stir evenly, heat to 100-110°C and reflux for reaction for 1-3h, then add polyfluoroalkyl diol, continue heating reflux for reaction for 1-3h, then remove n-propanol by reduced pressure distillation to obtain an anti-scaling agent.

[0036] In summary, the technical solution of the present application includes at least the following beneficial effects:

[0037] The inner layer surface roughness of the PE-RT floor heating pipe of the present application is small and has an oxygen barrier effect, which effectively reduces the thickness of the oxygen barrier outer layer while obtaining excellent oxygen barrier performance, and has little impact on the thermal conductivity of the floor heating pipe. DETAILED DESCRIPTION

[0038] The present application is further described in detail below in conjunction with specific preparation examples, embodiments and comparative examples.

[0039] Preparation Example

[0040] Preparation Example 1

[0041] An anti-fouling agent comprises a double-terminal epoxy polysiloxane with a polymerization degree of 100, a polyester diol with a molecular weight of 500, a polyfluoroalkyl diol and a tertiary amine catalyst, wherein the molar ratio of the double-terminal epoxy polysiloxane, the polyester diol and the polyfluoroalkyl diol is 1:0.1:0.9, and the amount of the tertiary amine catalyst is 1% of the total weight of the double-terminal epoxy polysiloxane, the polyester diol and the polyfluoroalkyl diol.

[0042] Among them, the polyester diol can be selected from aliphatic polyester diols such as polycaprolactone diol and polycarbonate diol. In this embodiment, the polyester diol is specifically selected from polycaprolactone diol. The polyfluoroalkyl diol is specifically selected from 1H,1H,7H,7H-perfluoro-1,7-heptanediol, with a molecular formula of HOCH2(CF2)5CH2OH; the tertiary amine catalyst is specifically selected from triethylenediamine.

[0043] In addition, the preparation method of the anti-scaling agent comprises the following steps:

[0044] Polyester diol, triethylene diamine and double-terminal epoxy polysiloxane are added to n-propanol, and the weight ratio of n-propanol to double-terminal epoxy polysiloxane is 50:1. After stirring evenly, the temperature is raised to 100°C and refluxed for reaction for 1 hour. Then, polyfluoroalkyl diol is added and the heating reflux reaction is continued for 2 hours. Then, the n-propanol is removed by reduced pressure distillation to obtain an anti-scaling agent.

[0045] Preparation Example 2-4

[0046] An anti-scaling agent, which is different from Preparation Example 1 in that the molar ratio of the double-terminal epoxy polysiloxane, the polyester diol, and the polyfluoroalkyl diol is different, as shown in Table 1 below:

[0047] Table 1

[0048] Preparation Example Molar ratio of double-terminal epoxy polysiloxane, polyester diol and polyfluoroalkyl diol Preparation Example 1 1:0.1:0.9 Preparation Example 2 1:0.3:0.7 Preparation Example 3 1:0.5:0.5 Preparation Example 4 1:0.9:0.1

[0049] Preparation Example 5-7

[0050] An anti-scaling agent, which is different from Preparation Example 1 in that the degree of polymerization of the double-terminal epoxy polysiloxane is different, as shown in Table 2 below:

[0051] Table 2

[0052] Preparation Example Degree of polymerization of double-terminal epoxy polysiloxane Preparation Example 1 100 Preparation Example 5 500 Preparation Example 6 1000 Preparation Example 7 1500

[0053] Preparation Example 8-9

[0054] An anti-scaling agent, which is different from Preparation Example 1 in that the molecular weight of the polyester diol is different, as shown in Table 3 below:

[0055] Table 3

[0056]

[0057]

[0058] Preparation Example 10-11

[0059] An anti-scaling agent, which is different from Preparation Example 1 in that the type of polyfluoroalkyl glycol is different, as shown in Table 4 below:

[0060] Table 4

[0061] Preparation Example Polyfluoroalkyl diol name Polyfluoroalkyl diol molecular formula Preparation Example 1 1H,1H,7H,7H-Perfluoro-1,7-heptanediol <![CDATA[HOCH2(CF2)5CH2OH]]> Preparation Example 10 1H,1H,9H,9H-Perfluoro-1,9-decanediol <![CDATA[HOCH2(CF2)7CH2OH]]> Preparation Example 11 1H,1H,12H,12H-Perfluoro-1,12-dodecanediol <![CDATA[HOCH2(CF2) 10 CH2OH]]>

[0062] Comparative Preparation Example

[0063] Comparative Preparation Example 1

[0064] An anti-scaling agent, which is different from Preparation Example 1 in that the ratio of raw materials is different.

[0065] In this preparation example, the molar ratio of double-terminal epoxy polysiloxane, polycaprolactone diol, and 1H,1H,7H,7H-perfluoro-1,7-heptanediol is 1:0.9:0.5.

[0066] Comparative Preparation Example 2

[0067] An anti-scaling agent, which differs from Preparation Example 1 in that:

[0068] The polycaprolactone diol was replaced by an equimolar amount of 1H,1H,7H,7H-perfluoro-1,7-heptanediol.

[0069] Comparative Preparation Example 3

[0070] An anti-scaling agent, which differs from Preparation Example 1 in that:

[0071] 1H,1H,7H,7H-perfluoro-1,7-heptanediol was replaced by an equimolar amount of polycaprolactone diol.

[0072] Example

[0073] Example 1

[0074] A high-speed extrusion type anti-scaling PE-RT floor heating pipe comprises a PE-RT inner layer, an adhesive layer and an oxygen-barrier outer layer which are arranged in sequence from inside to outside.

[0075] The PE-RT inner layer special material is composed of 100kg PE-RT resin, 1.5kg heat stabilizer, 18kg thermal conductive filler and 5kg anti-scaling agent prepared in Preparation Example 1. Among them, the PE-RT resin can be any PE-RT resin commonly used in the production of floor heating pipes. In this embodiment, the specific PE-RT resin is DGDZ3606, the heat stabilizer is specifically selected from dibasic lead phthalate, and the thermal conductive filler is specifically selected from graphene.

[0076] The special material for the bonding layer is specifically maleic anhydride grafted polyethylene ZJ-900E.

[0077] The special material for the oxygen-barrier outer layer is specifically ethylene-vinyl alcohol copolymer FP201B.

[0078] Among them, the preparation method of high-speed extrusion anti-scale PE-RT floor heating pipe includes the following steps:

[0079] S1. Extruder A extrudes the special material for the oxygen barrier outer layer. The processing temperature of extruder A is divided into five sections. The processing temperature of sections 1 to 3 is controlled at 170-190°C, and the processing temperature of sections 4 to 5 is controlled at 190-200°C; Extruder B extrudes the special material for the bonding layer. The processing temperature of extruder B is divided into five sections. The processing temperature of sections 1 to 3 is controlled at 180-190°C, and the processing temperature of sections 4 to 5 is controlled at 190-200°C; Extruder C extrudes the special material for the PE-RT inner layer. The processing temperature of extruder C is divided into five sections. The processing temperature of sections 1 to 3 is controlled at 180-190°C, and the processing temperature of sections 4 to 5 is controlled at 190-200°C;

[0080] S2, the three-layer material is co-extruded in a molten state using a three-layer co-extrusion composite extrusion die, the temperature of the three-layer co-extrusion composite extrusion die is controlled between 200-250°C, and the extrusion speed is controlled at 35m / min. Then, after vacuum sizing and cooling, a floor heating pipe is obtained. Among them, the floor heating pipe obtained in this embodiment has an outer diameter of 20mm, a wall thickness of 2.0mm, and an oxygen barrier outer layer thickness of 0.3mm.

[0081] Example 2-11

[0082] A high-speed extrusion type anti-scaling PE-RT floor heating pipe is different from Example 1 in that the anti-scaling agent used in the PE-RT inner layer is different, as shown in Table 5 below:

[0083] Table 5

[0084] Example Anti-scaling agent Example Anti-scaling agent Example 2 Preparation Example 2 Example 7 Preparation Example 7 Example 3 Preparation Example 3 Example 8 Preparation Example 8 Example 4 Preparation Example 4 Example 9 Preparation Example 9 Example 5 Preparation Example 5 Example 10 Preparation Example 10 Example 6 Preparation Example 6 Embodiment 11 Preparation Example 11

[0085] Comparative Example

[0086] Comparative Examples 1-3

[0087] A high-speed extrusion type anti-scaling PE-RT floor heating pipe, which is different from Example 1 in that the anti-scaling agent used in the PE-RT inner layer is different, as shown in Table 6 below:

[0088] Table 6

[0089] Comparative Example Anti-scaling agent Comparative Example 1 Comparative Preparation Example 1 Comparative Example 2 Comparative Preparation Example 2 Comparative Example 3 Comparative Preparation Example 3

[0090] Comparative Example 4

[0091] A high-speed extrusion anti-fouling PE-RT floor heating pipe, which differs from Example 1 in that the anti-fouling agent used in the PE-RT inner layer is a double-terminal epoxy polysiloxane with a degree of polymerization of 100.

[0092] Comparative Example 5

[0093] A high-speed extrusion anti-fouling PE-RT floor heating pipe, which differs from Example 1 in that the anti-fouling agent used in the PE-RT inner layer includes double-terminal epoxy polysiloxane with a polymerization degree of 100 and polyvinylidene fluoride, and the weight ratio of the double-terminal epoxy polysiloxane to the polyvinylidene fluoride is 1:1.

[0094] Performance testing

[0095] Surface roughness: Use i60 surface roughness measuring instrument to test the inner surface roughness of the pipe and record the arithmetic mean deviation Ra.

[0096] Oxygen permeability: Tested in accordance with GB / T 34437-2017 "Test method for oxygen permeability of multi-layer composite plastic pipes".

[0097] Tensile strength: Tested in accordance with GB / T 8804.2-2003 "Determination of tensile properties of thermoplastic pipes Part 3: Polyolefin pipes".

[0098] Table 7

[0099]

[0100]

[0101] Combining Example 1 with Comparative Examples 1-5 and the data recorded in Table 7, it can be seen that the anti-scaling agent prepared by using a double-terminal epoxy polysiloxane, polyester diol and polyfluoroalkyl diol in an appropriate molar ratio can not only improve the smoothness of the inner surface of the floor heating pipe, but also improve the oxygen barrier performance of the floor heating pipe, and can effectively improve the anti-scaling effect of the floor heating pipe. In addition, when the extrusion speed is controlled at 35m / min, the mechanical properties of the floor heating pipe are also excellent.

[0102] Combining Examples 1-4 and the data recorded in Table 7, it can be seen that when the molar ratio of double-ended epoxy polysiloxane, polyester diol and polyfluoroalkyl diol is 1:(0.3-0.5):(0.7-0.5), the smoothness of the inner surface of the floor heating pipe is relatively small. At the same time, the oxygen barrier performance of the floor heating pipe is significantly improved. The reason is that when the molar ratio of double-ended epoxy polysiloxane, polyester diol and polyfluoroalkyl diol is within the above range, the oxygen barrier performance of the floor heating pipe can be further improved.

[0103] Combining Example 1 with Examples 5-7 and the data recorded in Table 7, it can be seen that when the degree of polymerization of the double-ended epoxy polysiloxane is in the range of 500-1000, it is beneficial to further improve the oxygen barrier performance of the floor heating pipe.

[0104] Combining Example 1 with Examples 8-9 and the data recorded in Table 7, it can be seen that when the molecular weight of the polyester diol is in the range of 1000-2000, it is beneficial to further improve the oxygen barrier performance and tensile strength of the floor heating pipe.

[0105] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high-speed extrusion anti-scaling PE-RT floor heating pipe, characterized in that: It includes a PE-RT inner layer, an adhesive layer and an oxygen barrier outer layer, wherein the PE-RT inner layer includes the following raw materials in parts by weight: PE-RT resin: 100 parts Heat stabilizer: 1-2 parts Thermal conductive filler: 15-20 parts Anti-scaling agent: 4-6 parts The raw materials for preparing the anti-fouling agent include double-terminal epoxy polysiloxane, polyester diol, polyfluoroalkyl diol and tertiary amine catalyst, wherein the molar ratio of the double-terminal epoxy polysiloxane, polyester diol and polyfluoroalkyl diol is 1: (0.3-0.5): (0.7-0.5); the molar sum of the polyester diol and the polyfluoroalkyl diol does not exceed the double-terminal epoxy polysiloxane; the amount of the tertiary amine catalyst is 1-5% of the total weight of the double-terminal epoxy polysiloxane, polyester diol and polyfluoroalkyl diol.

2. The high-speed extrusion anti-scaling PE-RT floor heating pipe according to claim 1 is characterized in that: The degree of polymerization of the double-terminal epoxy polysiloxane is 100-1500.

3. The high-speed extrusion anti-scaling PE-RT floor heating pipe according to claim 2 is characterized in that: The degree of polymerization of the double-terminal epoxy polysiloxane is 500-1000.

4. The high-speed extrusion anti-scaling PE-RT floor heating pipe according to claim 1 is characterized in that: The polyfluoroalkyl glycol is HO(CH2) m (CF2) n (CH2) m OH, where m=1-4, n=3-12.

5. The high-speed extrusion anti-scaling PE-RT floor heating pipe according to claim 4 is characterized in that: The m=1-2, the n=7-8.

6. The high-speed extrusion anti-scaling PE-RT floor heating pipe according to claim 1 is characterized by: The molecular weight of the polyester diol is 500-3000.

7. The high-speed extrusion anti-scaling PE-RT floor heating pipe according to claim 6 is characterized by: The molecular weight of the polyester diol is 1000-2000.

8. The high-speed extrusion anti-scaling PE-RT floor heating pipe according to claim 1 is characterized by: The tertiary amine catalyst is selected from any one of triethylenediamine, N-alkylmorpholine, and bis(2-methyloxyethyl)ether or a combination of several of them.

9. A method for preparing a high-speed extrusion anti-scaling PE-RT floor heating pipe according to any one of claims 1 to 8, characterized in that: The following steps are involved: The polyester diol, the double-terminal epoxy polysiloxane and the polyfluoroalkyl diol are subjected to a ring-opening reaction under the catalytic action of a tertiary amine catalyst to obtain an anti-fouling agent; Melting the raw materials of the oxygen barrier outer layer to obtain an outer layer melt; Melting the raw material of the bonding layer to obtain a bonding layer melt; The PE-RT resin, the heat stabilizer, the heat conductive filler and the anti-fouling agent are mixed and melted to obtain an inner layer melt; A three-layer co-extrusion composite die is used to compositely extrude the outer layer melt, the adhesive layer melt and the inner layer melt, and then after vacuum sizing and cooling and shaping, the anti-scale PE-RT floor heating pipe is obtained; wherein, the temperature of the three-layer co-extrusion composite extrusion die is controlled between 200-250℃, and the extrusion speed is controlled at 35-40m / min.

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