Temperature-resistant PPR water supply pipe and preparation method thereof

Abstract

The invention discloses a temperature-resistant PPR water supply pipe and a preparation method thereof, and relates to the technical field of pipeline materials. The invention discloses a preparation method of a temperature-resistant PPR (polypropylene random copolymer) water supply pipe, which comprises the following steps: uniformly mixing PPR, a modifier and an assistant according to the weight percentage of raw materials, adding into a twin-screw extruder, and extruding and granulating to obtain master batch; adding the master batch into a single-screw extruder for melt blending, and then performing extrusion molding to obtain the temperature-resistant PPR water supply pipe. The preparation method comprises the following steps: organically modifying Na-montmorillonite by using vinyl trimethoxy silane to obtain organic montmorillonite; the organic montmorillonite is reacted with polypropylene and maleic anhydride to obtain the polypropylene / montmorillonite composite material. The prepared modifier and polypropylene random copolymer PPR are granulated through double-screw extrusion equipment, the temperature-resistant PPR water supply pipe is prepared through pipe extrusion equipment, and the prepared pipe is good in low-temperature toughness and high in high-temperature bearing strength.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline materials, and in particular to a temperature-resistant PPR water supply pipe and a preparation method thereof. Background Art

[0002] Polypropylene pipes have the characteristics of low cost, simple processing equipment and processing technology, easy matching of pipe fittings, weldability and easy recycling of waste. Compared with other synthetic resins, polypropylene has good comprehensive performance, mainly manifested in low relative density, good surface gloss, good heat resistance, etc., especially good stress cracking resistance and chemical resistance, so it has achieved rapid development in the field of building pipelines, especially water supply pipelines. However, it has not been widely used due to its poor temperature resistance and aging resistance. Over the years, in order to eliminate the shortcomings of low refrigerator melt strength and poor low-temperature impact resistance, polypropylene (PPH), block copolymer polypropylene (PPB) and random copolymer polypropylene (PPR) have been developed. The first generation of polypropylene pipes (PPH) have excellent rigidity and strength, but poor low-temperature impact resistance and are easily catalyzed, and are mainly used in high-temperature industrial sewage pipes; the second generation of polypropylene pipes (PPB) have good flexibility, especially excellent impact resistance at low temperatures, and are mainly used for drainage pipes and industrial sewage pipes, and are also used for low-pressure, low-temperature (60°C) hot and cold water transportation; the third generation of polypropylene pipes (PPR) have high transparency, high elasticity, good rigidity and strength, and improve the low-temperature brittleness of PPH, and have good creep resistance at higher temperatures. They are mainly used in hot and cold water supply with an operating temperature of 60-70°C, floor heating and snow melting systems with a dry working temperature of 30-70°C, and are green and environmentally friendly pipes suitable for modern civil building pipes and industrial pipe systems.

[0003] PPR pipe is a newly developed building pipe in the history of international pipe development. In particular, it has surpassed aluminum-plastic composite pipe in the application of water supply pipe. PPR resin is the main raw material for the production of PPR pipe. It is obtained by copolymerization of propylene and a small amount of olefin monomer under heating, pressure and catalyst. The random addition of copolymer monomer greatly improves the impact strength of PPR, and PPR has good heat resistance. Its Vicat softening point is 131.5℃, the highest working temperature can reach 95℃, and the long-term (50 years under 1.OMPa) use temperature can generally reach 70℃, which can fully meet the water supply requirements under general conditions. However, at low temperatures, some molecular chains in the molecular structure cannot move freely. When impacted by external forces, the molecules cannot consume external energy through movement, so they can only consume energy through heat generation and friction within the molecules, that is, low-temperature brittleness occurs; its external surface is that when the temperature is below 5℃, the pipe has linear cracking, and the cracking often starts from the inner pipe and extends to the outer pipe. There are potential safety risks, which greatly limits the application of PPR pipe. Summary of the invention

[0004] The purpose of the present invention is to provide a temperature-resistant PPR water supply pipe and a preparation method thereof to solve the following technical problems:

[0005] The PPR resin used in existing PPR water supply pipes has a narrow molecular weight distribution, extremely large molecular weight and weak crystallization performance, which leads to high material processing difficulty, high thermal expansion coefficient and poor low-temperature toughness, and is easy to deform when used for hot water pipes.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a temperature-resistant PPR water supply pipe comprises the following steps:

[0008] S1: After uniformly mixing random copolymer polypropylene PPR, modifier and additive according to the weight percentage of raw materials, adding them into a twin-screw extruder for extrusion granulation to obtain masterbatch;

[0009] S2: adding the masterbatch into a single screw extruder for melt blending and extrusion molding to obtain a heat-resistant PPR water supply pipe;

[0010] The preparation method of the modifier comprises the following steps:

[0011] A1: Add deionized water, anhydrous ethanol and vinyl trimethoxysilane into a reaction kettle and disperse them evenly, adjust the pH to 4-5, add sodium montmorillonite, control the temperature to 50-60°C, keep the temperature for 3-6 hours under stirring, filter, wash and dry to obtain organic montmorillonite;

[0012] A2: Add polypropylene, maleic anhydride, dibenzoyl peroxide and ethyl acetate into a reaction kettle and disperse them evenly, add organic montmorillonite, control the temperature at 80-90°C, keep the reaction warm for 3-6 hours, filter, wash and dry to obtain a modifier.

[0013] As a further solution of the present invention: the modifier accounts for 5-10% of the total mass of the masterbatch.

[0014] As a further solution of the present invention: the addition ratio of deionized water, anhydrous ethanol, vinyltrimethoxysilane and sodium montmorillonite in A1 is 10-20 mL: 40-90 mL: 2-4 g: 10 g.

[0015] As a further embodiment of the present invention: the addition ratio of PP, maleic anhydride, dibenzoyl peroxide, ethyl acetate and organized montmorillonite in A2 is 10 g: 2-4 g: 0.1-0.3 g: 100-200 mL: 3-6 g.

[0016] As a further solution of the present invention: the auxiliary agent includes a lubricant; the lubricant is obtained by mixing stearic acid and polyethylene wax in a mass ratio of 1:0.5-1; the lubricant accounts for 0.2-0.4% of the total mass of the masterbatch.

[0017] As a further solution of the present invention: the auxiliary agent also includes an antioxidant; the antioxidant is any one of antioxidant 245, antioxidant 168, and antioxidant 1010; the antioxidant accounts for 0.1-0.3% of the total mass of the masterbatch.

[0018] As a further solution of the present invention: the screw speed of the twin-screw extruder in S1 is 40-100 rpm and the extrusion temperature is 200-220°C.

[0019] As a further solution of the present invention: the melting temperature of the single screw extruder in S2 is 240-270° C., and the screw speed is 160-180 rpm.

[0020] A temperature-resistant PPR water supply pipe is made by any one of the above preparation methods.

[0021] Beneficial effects of the present invention:

[0022] The present application first uses a vinyl silane coupling agent to organically modify montmorillonite, and the silanol generated by its hydrolysis and condensation undergoes polycondensation to form an organic coupling layer on the surface of the sodium-based montmorillonite to obtain an organic montmorillonite; and the vinyl on the surface of the organic montmorillonite is copolymerized with maleic anhydride and polypropylene to obtain a modifier. The present application uses the prepared modifier to granulate with a random copolymerization polypropylene PPR twin-screw extruder, and prepares a heat-resistant PPR water supply pipe through a pipe extruder.

[0023] The modifier added to the heat-resistant PPR water supply pipe in this application utilizes the strong interaction between the polar groups carried by the organic montmorillonite in the modifier and the maleic anhydride grafted polypropylene, which is not only conducive to the intercalation, exfoliation and stability of montmorillonite in the random copolymer polypropylene PPR, but also significantly improves the mechanical properties of the random copolymer polypropylene PPR; and the random copolymer polypropylene PPR and montmorillonite produce a cross-linked structure, which improves the compatibility and bonding strength of the interface, and has a certain degree of hindering effect on the random fracture of the random copolymer polypropylene PPR molecular chain. After toughening and strengthening by the modifier, the impact resistance of the PPR pipe is greatly improved, the interfacial bonding force of the blending system is enhanced, and the PPR material is transformed from brittle to tough. The pipe prepared in this application has good low-temperature toughness and high high-temperature pressure-bearing strength. DETAILED DESCRIPTION

[0024] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The preparation method of the modifying agent of embodiment 1 comprises the following steps:

[0026] A1: 10 mL of deionized water, 40 mL of anhydrous ethanol, and 2 g of vinyltrimethoxysilane were added to a reaction kettle and dispersed evenly. The pH was adjusted to 4, and 10 g of sodium montmorillonite (cation exchange capacity 120 meq / 100 g) was added. The temperature was controlled at 50°C, and the mixture was kept warm for 3 h under stirring. The mixture was filtered, washed, and dried to obtain an organic montmorillonite.

[0027] A2: 10 g of polypropylene (F401, purchased from Lanzhou Petrochemical Company of PetroChina Co., Ltd.), 2 g of maleic anhydride, 0.1 g of dibenzoyl peroxide, and 100 mL of ethyl acetate were added into a reactor and dispersed evenly, 3 g of organic montmorillonite was added, the temperature was controlled at 80°C, the reaction was kept warm for 3 h, filtered, washed, and dried to obtain a modifier.

[0028] The preparation method of the modifying agent of embodiment 2 comprises the following steps:

[0029] A1: 20 mL of deionized water, 80 mL of anhydrous ethanol and 4 g of vinyltrimethoxysilane were added to a reaction kettle and dispersed evenly. The pH was adjusted to 5, and 10 g of sodium montmorillonite (cation exchange capacity 120 meq / 100 g) was added. The temperature was controlled at 60°C, and the mixture was kept warm for 6 h under stirring. The mixture was filtered, washed and dried to obtain an organic montmorillonite.

[0030] A2: 10 g of polypropylene (F401, purchased from Lanzhou Petrochemical Company of China National Petroleum Corporation), 3 g of maleic anhydride, 0.2 g of dibenzoyl peroxide, and 200 mL of ethyl acetate were added into a reactor and dispersed evenly, 5 g of organic montmorillonite was added, the temperature was controlled at 85°C, the reaction was kept warm for 4 hours, and then filtered, washed, and dried to obtain a modifier.

[0031] The preparation method of the modifying agent of embodiment 3 comprises the following steps:

[0032] A1: 10 mL of deionized water, 90 mL of anhydrous ethanol, and 4 g of vinyltrimethoxysilane were added to a reaction kettle and dispersed evenly. The pH was adjusted to 5, and 10 g of sodium montmorillonite (cation exchange capacity 120 meq / 100 g) was added. The temperature was controlled at 60°C, and the mixture was kept warm for 6 h under stirring. The mixture was filtered, washed, and dried to obtain an organic montmorillonite.

[0033] A2: 10 g of polypropylene (F401, purchased from Lanzhou Petrochemical Company of PetroChina Co., Ltd.), 4 g of maleic anhydride, 0.3 g of dibenzoyl peroxide, and 200 mL of ethyl acetate were added into a reactor and dispersed evenly, 6 g of organic montmorillonite was added, the temperature was controlled at 90°C, the reaction was kept warm for 6 hours, and then filtered, washed, and dried to obtain a modifier.

[0034] Embodiment 4 A method for preparing a heat-resistant PPR water supply pipe comprises the following steps:

[0035] S1: Random copolymer polypropylene PPR (PA14D, purchased from Daqing Branch of PetroChina Co., Ltd.), 10g of the modifier prepared in Example 1, 0.2g of stearic acid, 0.1g of polyethylene wax, and 0.3g of antioxidant 245 were mixed uniformly, and added into a twin-screw extruder for extrusion granulation at a screw speed of 50rpm and an extrusion temperature of 210°C to obtain a masterbatch;

[0036] S2: Add the masterbatch into a single screw extruder for melt blending and then extrude it into a mold. The melting temperature of the single screw extruder is 240°C and the screw speed is 170rpm. After vacuum cooling, pulling and cutting, a heat-resistant PPR water supply pipe is obtained.

[0037] Embodiment 5 A method for preparing a heat-resistant PPR water supply pipe comprises the following steps:

[0038] S1: Random copolymer polypropylene PPR (PA14D, purchased from Daqing Branch of PetroChina Co., Ltd.), 10g of the modifier prepared in Example 2, 0.2g of stearic acid, 0.1g of polyethylene wax, and 0.3g of antioxidant 245 were mixed uniformly, and added into a twin-screw extruder for extrusion granulation, with a screw speed of 50rpm and an extrusion temperature of 210°C to obtain a masterbatch;

[0039] S2: Add the masterbatch into a single screw extruder for melt blending and then extrude it into a mold. The melting temperature of the single screw extruder is 240°C and the screw speed is 170rpm. After vacuum cooling, pulling and cutting, a heat-resistant PPR water supply pipe is obtained.

[0040] Embodiment 6 A method for preparing a heat-resistant PPR water supply pipe comprises the following steps:

[0041] S1: Random copolymer polypropylene PPR (PA14D, purchased from Daqing Branch of PetroChina Co., Ltd.), 10g of the modifier prepared in Example 3, 0.2g of stearic acid, 0.1g of polyethylene wax, and 0.3g of antioxidant 245 were mixed uniformly, and added into a twin-screw extruder for extrusion granulation at a screw speed of 50rpm and an extrusion temperature of 210°C to obtain a masterbatch;

[0042] S2: Add the masterbatch into a single screw extruder for melt blending and then extrude it into a mold. The melting temperature of the single screw extruder is 240°C and the screw speed is 170rpm. After vacuum cooling, pulling and cutting, a heat-resistant PPR water supply pipe is obtained.

[0043] The preparation method of the modifier of Comparative Example 1 comprises the following steps:

[0044] A1: 20 mL of deionized water, 80 mL of anhydrous ethanol and 4 g of vinyltrimethoxysilane were added to a reaction kettle and dispersed evenly. The pH was adjusted to 5, and 10 g of sodium montmorillonite (cation exchange capacity 120 meq / 100 g) was added. The temperature was controlled at 60°C, and the mixture was kept warm for 6 h under stirring. The mixture was filtered, washed and dried to obtain an organic montmorillonite.

[0045] A2: 10 g of polypropylene (F401, purchased from Lanzhou Petrochemical Company of PetroChina Co., Ltd.), 3 g of maleic anhydride, 0.2 g of dibenzoyl peroxide, and 200 mL of ethyl acetate were added into a reaction kettle and dispersed evenly. The temperature was controlled at 85° C. and the reaction was kept warm for 4 h. The mixture was filtered, washed, and dried to obtain component 1.

[0046] A3: Component 1 prepared in step A2 is blended with 5 g of the organized montmorillonite prepared in step A1 to obtain a modifier.

[0047] The preparation method of the modifier of Comparative Example 2 comprises the following steps:

[0048] 20 mL of deionized water, 80 mL of anhydrous ethanol, and 4 g of vinyltrimethoxysilane were added to the reaction kettle and dispersed evenly. The pH was adjusted to 5. 10 g of sodium montmorillonite (cation exchange capacity: 120 meq / 100 g) was added. The temperature was controlled at 60° C. and kept warm for 6 h under stirring. The modified agent was filtered, washed, and dried.

[0049] The preparation method of the modifier of Comparative Example 3 comprises the following steps:

[0050] 10 g of polypropylene (F401, purchased from Lanzhou Petrochemical Company of China National Petroleum Corporation), 4 g of maleic anhydride, 0.3 g of dibenzoyl peroxide, and 200 mL of ethyl acetate were added to a reactor and dispersed evenly, 6 g of sodium montmorillonite (cation exchange capacity 120 meq / 100 g) was added, the temperature was controlled at 90°C, the reaction was kept warm for 6 hours, and then filtered, washed, and dried to obtain a modifier.

[0051] Comparative Example 4 A method for preparing a temperature-resistant PPR water supply pipe comprises the following steps:

[0052] S1: Random copolymer polypropylene PPR (PA14D, purchased from Daqing Branch of PetroChina Co., Ltd.), 10g of the modifier prepared in Comparative Example 1, 0.2g of stearic acid, 0.1g of polyethylene wax, and 0.3g of antioxidant 245 were mixed uniformly, and added into a twin-screw extruder for extrusion granulation at a screw speed of 50rpm and an extrusion temperature of 210°C to obtain a masterbatch;

[0053] S2: Add the masterbatch into a single screw extruder for melt blending and then extrude it into a mold. The melting temperature of the single screw extruder is 240°C and the screw speed is 170rpm. After vacuum cooling, pulling and cutting, a heat-resistant PPR water supply pipe is obtained.

[0054] Comparative Example 5 A method for preparing a heat-resistant PPR water supply pipe comprises the following steps:

[0055] S1: Random copolymer polypropylene PPR (PA14D, purchased from Daqing Branch of PetroChina Co., Ltd.), 10g of the modifier prepared in Comparative Example 2, 0.2g of stearic acid, 0.1g of polyethylene wax, and 0.3g of antioxidant 245 were mixed uniformly, and added into a twin-screw extruder for extrusion granulation at a screw speed of 50rpm and an extrusion temperature of 210°C to obtain a masterbatch;

[0056] S2: Add the masterbatch into a single screw extruder for melt blending and then extrude it into a mold. The melting temperature of the single screw extruder is 240°C and the screw speed is 170rpm. After vacuum cooling, pulling and cutting, a heat-resistant PPR water supply pipe is obtained.

[0057] Comparative Example 6 A method for preparing a temperature-resistant PPR water supply pipe comprises the following steps:

[0058] S1: Random copolymer polypropylene PPR (PA14D, purchased from Daqing Branch of PetroChina Co., Ltd.), 10g of the modifier prepared in Comparative Example 3, 0.2g of stearic acid, 0.1g of polyethylene wax, and 0.3g of antioxidant 245 were mixed uniformly, and added into a twin-screw extruder for extrusion granulation at a screw speed of 50rpm and an extrusion temperature of 210°C to obtain a masterbatch;

[0059] S2: Add the masterbatch into a single screw extruder for melt blending and then extrude it into a mold. The melting temperature of the single screw extruder is 240°C and the screw speed is 170rpm. After vacuum cooling, pulling and cutting, a heat-resistant PPR water supply pipe is obtained.

[0060] Performance Testing

[0061] (1) Tensile properties: The test was conducted according to GB / T 1040-2006 “Test method for tensile properties of plastics”, with a tensile rate of 50 mm / min. The test results are shown in Table 1.

[0062] (2) Impact resistance: The test was conducted in accordance with GB / T 1043.1-2008 “Determination of impact resistance of simply supported beams of plastics Part 1: Non-instrumented impact test”. The pendulum was 4J. The test results are shown in Table 1.

[0063] (3) Bending properties: The test was conducted in accordance with GB / T 9341-2008 “Determination of flexural properties of plastics” at a rate of 2 mm / min. The test results are shown in Table 1.

[0064] (4) Thermal deformation performance: The test was conducted according to GB / T 1634.1-2004 “Determination of deformation temperature of plastics under load Part 1: General test method”, with a pressure of 0.45 MPa and a heating rate of 120°C / h. The test results are shown in Table 1.

[0065] Table 1: Statistical table of performance test data of Examples 4-6 and Comparative Examples 4-6

[0066]

[0067]

[0068] As can be seen from Table 1, when the modifier prepared in the present application is added to the pipe, the prepared pipe has excellent mechanical properties and temperature resistance, and has the characteristics of good low-temperature toughness and high high-temperature compressive strength.

[0069] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a heat-resistant PPR water supply pipe, characterized in that: The steps include: S1: After uniformly mixing random copolymer polypropylene PPR, modifier and additive according to the weight percentage of raw materials, adding them into a twin-screw extruder for extrusion granulation to obtain masterbatch; S2: adding the masterbatch into a single screw extruder for melt blending and extrusion molding to obtain a heat-resistant PPR water supply pipe; The preparation method of the modifier comprises the following steps: A1: Add deionized water, anhydrous ethanol and vinyl trimethoxysilane into a reaction kettle and disperse them evenly, adjust the pH to 4-5, add sodium montmorillonite, control the temperature to 50-60°C, keep the temperature for 3-6 hours under stirring, filter, wash and dry to obtain organic montmorillonite; A2: Add polypropylene, maleic anhydride, dibenzoyl peroxide and ethyl acetate into a reaction kettle and disperse them evenly, add organic montmorillonite, control the temperature at 80-90°C, keep the reaction warm for 3-6 hours, filter, wash and dry to obtain a modifier.

2. The method for preparing a heat-resistant PPR water supply pipe according to claim 1, characterized in that: The modifier accounts for 5-10% of the total mass of the masterbatch.

3. The method for preparing a heat-resistant PPR water supply pipe according to claim 1, characterized in that: The addition ratio of deionized water, anhydrous ethanol, vinyl trimethoxysilane and sodium montmorillonite in A1 is 10-20 mL: 40-90 mL: 2-4 g: 10 g.

4. The method for preparing a heat-resistant PPR water supply pipe according to claim 1, characterized in that: The addition ratio of PP, maleic anhydride, dibenzoyl peroxide, ethyl acetate and organized montmorillonite in A2 is 10g:2-4g:0.1-0.3g:100-200mL:3-6g.

5. The method for preparing a heat-resistant PPR water supply pipe according to claim 1, characterized in that: The auxiliary agent includes a lubricant; the lubricant is obtained by mixing stearic acid and polyethylene wax in a mass ratio of 1:0.5-1; the lubricant accounts for 0.2-0.4% of the total mass of the masterbatch.

6. The method for preparing a heat-resistant PPR water supply pipe according to claim 5, characterized in that: The auxiliary agent also includes an antioxidant; the antioxidant is any one of antioxidant 245, antioxidant 168, and antioxidant 1010; the antioxidant accounts for 0.1-0.3% of the total mass of the masterbatch.

7. The method for preparing a heat-resistant PPR water supply pipe according to claim 1, characterized in that: The twin-screw extruder in S1 has a screw speed of 40-100 rpm and an extrusion temperature of 200-220°C.

8. The method for preparing a heat-resistant PPR water supply pipe according to claim 1, characterized in that: The single screw extruder in S2 has a melt temperature of 240-270°C and a screw speed of 160-180 rpm.

9. A heat-resistant PPR water supply pipe, characterized in that: Prepared by the preparation method described in any one of claims 1 to 8.

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