Preparation process of high-toughness PET-PE composite material

Abstract

This invention relates to the field of plastic alloy technology and discloses a preparation process for a high-toughness, heat-insulating PET-PE composite material. The invention involves melt-blending and extruding 10-25 parts by weight of polyethylene terephthalate (PET), 75-90 parts by weight of polyethylene resin, and 5-30 parts by weight of PET-grafted silica aerogel, followed by pelletizing to obtain the high-toughness, heat-insulating PET-PE composite material. The silica aerogel has PET molecular chains grafted onto its surface, and simultaneously, it chemically bonds long aliphatic carbon chains similar to those of polyethylene resin. This results in excellent interfacial compatibility between the silica aerogel and both the PET and PE resins in the composite material. The composite material maintains good flexural strength and impact strength. Furthermore, the silica aerogel is uniformly dispersed within the composite matrix, forming a continuous insulating network, reducing the thermal conductivity of the composite material, and thus exhibiting excellent heat insulation performance.

Description

Technical Field

[0001] This invention relates to the field of plastic alloy technology, specifically to a preparation process for a heat-insulating and high-toughness PET-PE composite material. Background Technology

[0002] Polyethylene (PE) possesses excellent electrical insulation, resistance to high and low temperatures, and flexibility. Polyethylene terephthalate (PET) exhibits high mechanical strength, strong high-temperature resistance, and good chemical stability. Blending PE and PET can produce high-performance plastic alloys, widely used in the automotive, electronics, precision instrument, and packaging materials industries. However, PE, PET, and their composite alloys have relatively high thermal conductivity and poor heat insulation properties, hindering their practical applications in insulated packaging and thermal insulation materials.

[0003] Silica aerogel is simple to prepare, inexpensive, and readily available. Its porous structure and low thermal conductivity make it important for applications in thermal insulation materials. However, silica aerogel has poor compatibility with polymers such as polyethylene and polyethylene terephthalate, and its low mechanical strength significantly impacts the mechanical properties of the materials. Chinese patent CN118496545B discloses a scented polyethylene garbage bag and its preparation method. It uses porous silica aerogel as a carrier for natural plant essential oils, loads a polydopamine outer layer onto the aerogel surface, grafts a composite quaternized polyethyleneimine, and then extrudes and blow-films it with polyethylene to obtain a scented polyethylene garbage bag with water resistance and antibacterial properties. However, this patent does not address the problem of polyethylene's high thermal conductivity and poor insulation performance. Summary of the Invention

[0004] (I) Technical problem to be solved: In view of the shortcomings of the existing technology, the present invention provides a preparation process of high-toughness PET-PE composite material, which solves the problem of poor thermal insulation performance of PET-PE composite material.

[0005] (II) Technical Solution: A preparation process for a heat-insulating and high-toughness PET-PE composite material:

[0006] (1) Polyethylene terephthalate is molded into a film and placed in a plasma treatment instrument. Plasma treatment is carried out in an ammonia atmosphere with an ammonia flow rate of 100-200 mL / min, a discharge power of 50-80 W, and a treatment time of 10-20 min to obtain aminated polyethylene terephthalate.

[0007] (2) Add KH550 to water, sonicate in an ultrasonic instrument and heat to 45-55℃, add silica aerogel, react for 10-20 min, dry to remove water, wash with ethanol, dry to obtain KH550-silica aerogel.

[0008] (3) Add 5-aminoisophthalic acid, fatty acyl chloride, and catalyst to the solvent in a molar ratio of 1:(1-1.4):(3-3.6). Stir the reaction at 20-30℃ for 18-24 h, then distill under reduced pressure. Recrystallize the product in chloroform to obtain 5-(fatty acid ester)isophthalic acid. The reaction formula is:

[0009]

[0010] (4) Aminated polyethylene terephthalate, KH550-silica aerogel and 5-(fatty acid ester) isophthalic acid are added to a screw extruder and melt-blended and extruded to obtain PET grafted silica aerogel.

[0011] (5) Add 10-25 parts by weight of polyethylene terephthalate, 75-90 parts by weight of polyethylene resin, 5-30 parts by weight of PET grafted silica aerogel, and 0.2-0.3 parts by weight of antioxidant to a screw extruder, melt-blend and extrude, and pelletize to obtain a heat-insulating and high-toughness PET-PE composite material.

[0012] Preferably, the solvent in (3) is N,N-dimethylformamide or tetrahydrofuran.

[0013] Preferably, the structural formula of the fatty acyl chloride in (3) is C n H 2n+1 COCl, n is 11-17.

[0014] Preferably, the catalyst in (3) is pyridine or 4-dimethylaminopyridine.

[0015] Preferably, in (4), the amount of amino-modified polyethylene terephthalate is 100 parts by weight, KH550-silica aerogel is 20-40 parts by weight, and 5-(fatty acid ester) isophthalic acid is 3-8 parts by weight.

[0016] Preferably, in (4), the temperature of the screw extruder in sections 1-5 is 240-270℃ and the screw speed is 30-60r / min.

[0017] Preferably, in (5), the temperature of the screw extruder in sections 1-5 is 180-265℃ and the screw speed is 50-100r / min.

[0018] (III) Beneficial technical effects: The present invention involves high-temperature melt blending of aminated polyethylene terephthalate, KH550-silica aerogel, and 5-(palmitate) isophthalic acid. 5-(palmitate) isophthalic acid contains two carboxyl groups, which undergo amidation reactions with the amino groups of polyethylene terephthalate and silica aerogel, respectively, thereby grafting polyethylene terephthalate molecules onto the surface of silica aerogel, achieving the coating effect of silica aerogel. Furthermore, 5-(palmitate) isophthalic acid contains long aliphatic carbon chains, which are chemically bonded to PET-grafted silica aerogel.

[0019] This invention involves the melt blending of polyethylene resin, polyethylene terephthalate (PET), and PET-grafted silica aerogel to obtain a PET-PE composite material. Because PET molecular chains are grafted onto the surface of the silica aerogel, it exhibits excellent interfacial compatibility with the PET in the composite material. Simultaneously, the PET-grafted silica aerogel chemically bonds with long aliphatic carbon chains similar to those in the polyethylene resin, further enhancing interfacial compatibility between the silica aerogel and the PE resin in the composite material and improving the dispersibility of the aerogel. The excellent compatibility between the silica aerogel and the PET-PE composite material has minimal impact on the mechanical properties of the composite material, allowing it to maintain good flexural and impact strength. Furthermore, the silica aerogel is uniformly dispersed within the composite matrix, forming a continuous insulating network, reducing the thermal conductivity of the composite material, and thus providing excellent thermal insulation performance. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0021] Polyethylene terephthalate (PET), model K2012, purchased from Dongguan Weicai Plastic Raw Materials Co., Ltd. Polyethylene resin, model HMA-028, purchased from Dongguan Kaili New Materials Co., Ltd. Silica aerogel, white granular, purchased from Senate (Guangdong) New Materials Technology Co., Ltd.

[0022] Example 1:

[0023] (1) Polyethylene terephthalate was molded into a film and placed in a plasma treatment instrument. Plasma treatment was carried out in an ammonia atmosphere with an ammonia flow rate of 200 mL / min, a discharge power of 70 W, and a treatment time of 10 min to obtain aminated polyethylene terephthalate.

[0024] (2) Add 15g of KH550 to 400mL of water, sonicate and heat to 50℃ in an ultrasonic instrument, add 50g of silica aerogel, react for 15min, dry to remove water, wash with ethanol, dry, and obtain KH550-silica aerogel.

[0025] (3) Add 20 mmol of 5-aminoisophthalic acid, 24 mmol of palmitoyl chloride, and 60 mmol of 4-dimethylaminopyridine to 80 mL of N,N-dimethylformamide. Stir the mixture at 20 °C for 24 h. Distill under reduced pressure. Recrystallize the product in chloroform to obtain 5-(palmitate)isophthalic acid. The structural formula is:

[0026]

[0027] (4) 100g of amino-modified polyethylene terephthalate, 20g of KH550-silica aerogel and 3g of 5-(palmitate) isophthalic acid were added to a screw extruder. The temperatures of sections 1-5 were 240℃, 260℃, 270℃, 270℃ and 265℃, and the screw speed was 50r / min. The mixture was melt-blended and extruded to obtain PET-grafted silica aerogel.

[0028] (5) Add 100g polyethylene terephthalate, 900g polyethylene resin, 50g PET grafted silica aerogel and 3g antioxidant 1076 to a screw extruder. The temperatures of sections 1-5 are 180℃, 245℃, 260℃, 265℃ and 265℃ respectively. The screw speed is 50r / min. Melt blend extrusion, pelletize and obtain heat-insulating and high-toughness PET-PE composite material.

[0029] Comparative Example 1:

[0030] (1) 100g of polyethylene terephthalate, 20g of silica aerogel, and 3g of 5-(palmitate) isophthalic acid (prepared from Example 1) were added to a screw extruder. The temperatures of sections 1-5 were 240℃, 260℃, 270℃, 270℃, and 265℃, and the screw speed was 50r / min. The mixture was melt-blended and extruded to obtain PET-silica aerogel.

[0031] (2) 100g polyethylene terephthalate, 900g polyethylene resin, 50g PET-silica aerogel and 3g antioxidant 1076 were added to a screw extruder. The temperatures of sections 1-5 were 180℃, 245℃, 260℃, 265℃ and 265℃ respectively. The screw speed was 50r / min. The mixture was melt-blended and extruded, and then pelletized to obtain a heat-insulating and high-toughness PET-PE composite material.

[0032] Comparative Example 2:

[0033] (1) 100g of polyethylene terephthalate, 20g of KH550-silica aerogel (prepared in Example 1) and 3g of 5-(palmitate) isophthalic acid (prepared in Example 1) were added to a screw extruder. The temperatures of sections 1-5 were 240℃, 260℃, 270℃, 270℃ and 265℃, and the screw speed was 50r / min. The mixture was melt-blended and extruded to obtain PET-silica aerogel.

[0034] (2) 100g polyethylene terephthalate, 900g polyethylene resin, 50g PET-silica aerogel and 3g antioxidant 1076 were added to a screw extruder. The temperatures of sections 1-5 were 180℃, 245℃, 260℃, 265℃ and 265℃ respectively. The screw speed was 50r / min. The mixture was melt-blended and extruded, and then pelletized to obtain a heat-insulating and high-toughness PET-PE composite material.

[0035] Comparative Example 3:

[0036] (1) 100g of amino-modified polyethylene terephthalate (prepared in Example 1), 20g of silica aerogel, and 3g of 5-(palmitate) isophthalic acid (prepared in Example 1) were added to a screw extruder. The temperatures of sections 1-5 were 240℃, 260℃, 270℃, 270℃, and 265℃, and the screw speed was 50r / min. The mixture was melt-blended and extruded to obtain PET-silica aerogel.

[0037] (2) 100g polyethylene terephthalate, 900g polyethylene resin, 50g PET-silica aerogel and 3g antioxidant 1076 were added to a screw extruder. The temperatures of sections 1-5 were 180℃, 245℃, 260℃, 265℃ and 265℃ respectively. The screw speed was 50r / min. The mixture was melt-blended and extruded, and then pelletized to obtain a heat-insulating and high-toughness PET-PE composite material.

[0038] Comparative Example 4:

[0039] (1) 100g of amino-modified polyethylene terephthalate (prepared in Example 1), 20g of KH550-silica aerogel (prepared in Example 1), and 3g of isophthalic acid were added to a screw extruder. The temperatures of sections 1-5 were 240℃, 260℃, 270℃, 270℃, and 265℃, and the screw speed was 50r / min. The mixture was melt-blended and extruded to obtain PET-grafted silica aerogel.

[0040] (2) 100g polyethylene terephthalate, 900g polyethylene resin, 50g PET grafted silica aerogel and 3g antioxidant 1076 were added to a screw extruder. The temperatures of sections 1-5 were 180℃, 245℃, 260℃, 265℃ and 265℃ respectively. The screw speed was 50r / min. The mixture was melt-blended and extruded, and then pelletized to obtain a heat-insulating and high-toughness PET-PE composite material.

[0041] Example 2:

[0042] (1) Polyethylene terephthalate was molded into a film and placed in a plasma treatment instrument. Plasma treatment was carried out in an ammonia atmosphere with an ammonia flow rate of 150 mL / min, a discharge power of 50 W, and a treatment time of 20 min to obtain aminated polyethylene terephthalate.

[0043] (2) Add 20g of KH550 to 500mL of water, sonicate and heat to 55℃ in an ultrasonic instrument, add 50g of silica aerogel, react for 10min, dry to remove water, wash with ethanol, dry, and obtain KH550-silica aerogel.

[0044] (3) Add 20 mmol of 5-aminoisophthalic acid, 20 mmol of stearoyl chloride, and 60 mmol of pyridine to 60 mL of tetrahydrofuran. Stir the mixture at 30 °C for 18 h, then distill under reduced pressure. Recrystallize the product in chloroform to obtain 5-(stearate)isophthalic acid. The structural formula is as follows:

[0045] (4) 100g of amino-modified polyethylene terephthalate, 30g of KH550-silica aerogel and 5g of 5-(stearate) isophthalic acid were added to a screw extruder. The temperatures of sections 1-5 were 240℃, 260℃, 270℃, 270℃ and 265℃, and the screw speed was 30r / min. The mixture was melt-blended and extruded to obtain PET-grafted silica aerogel.

[0046] (5) Add 200g polyethylene terephthalate, 800g polyethylene resin, 180g PET grafted silica aerogel and 3g antioxidant 1076 to a screw extruder. The temperatures of sections 1-5 are 180℃, 245℃, 260℃, 265℃ and 265℃ respectively. The screw speed is 100r / min. Melt blend extrusion and pelletizing are performed to obtain a heat-insulating and high-toughness PET-PE composite material.

[0047] Example 3:

[0048] (1) Polyethylene terephthalate was molded into a film and placed in a plasma treatment instrument. Plasma treatment was carried out in an ammonia atmosphere with an ammonia flow rate of 100 mL / min, a discharge power of 80 W, and a treatment time of 20 min to obtain aminated polyethylene terephthalate.

[0049] (2) Add 25g of KH550 to 500mL of water, sonicate and heat to 45℃ in an ultrasonic instrument, add 50g of silica aerogel, react for 20min, dry to remove water, wash with ethanol, dry, and obtain KH550-silica aerogel.

[0050] (3) Add 20 mmol of 5-aminoisophthalic acid, 28 mmol of lauroyl chloride, and 72 mmol of 4-dimethylaminopyridine to 80 mL of N,N-dimethylformamide. Stir the mixture at 25 °C for 24 h. Distill under reduced pressure. Recrystallize the product in chloroform to give 5-(laurate)isophthalic acid. The structural formula is:

[0051] (4) 100g of amino-modified polyethylene terephthalate, 40g of KH550-silica aerogel and 8g of 5-(laurate) isophthalic acid were added to a screw extruder. The temperatures of sections 1-5 were 240℃, 260℃, 270℃, 270℃ and 265℃, and the screw speed was 60r / min. The mixture was melt-blended and extruded to obtain PET-grafted silica aerogel.

[0052] (5) Add 250g polyethylene terephthalate, 750g polyethylene resin, 300g PET grafted silica aerogel and 2g antioxidant 1076 to a screw extruder. The temperatures of sections 1-5 are 180℃, 245℃, 260℃, 265℃ and 265℃ respectively. The screw speed is 100r / min. Melt blend extrusion and pelletizing are performed to obtain a heat-insulating and high-toughness PET-PE composite material.

[0053] PET-PE composite materials were injection molded in an injection molding machine at temperatures of 240℃, 260℃, and 270℃ in stages 1-3, producing specimens. Thermal conductivity was tested according to ASTM D5930-09 standard. Impact strength was tested according to GB / T 1843-2008 standard. Flexural strength was tested according to GB / T 9341-2008 standard.

[0054] Table 1 Performance Testing of PET-PE Composite Materials

[0055]

[0056] After testing, the thermal conductivity of the PET-PE composite material in Example 1 was found to be only 0.1729 W·m. -1 ·K-1 It has excellent thermal insulation properties, with a flexural strength of 35.70 MPa and an impact strength of 9.16 kJ / m. 2 The excellent mechanical properties are mainly due to the fact that during the high-temperature melt blending process, 5-(palmitate) isophthalic acid contains two carboxyl groups, which undergo amidation reactions with the amino groups of polyethylene terephthalate and KH550-silica aerogel, respectively. This results in the polyethylene terephthalate molecules being grafted onto the surface of the silica aerogel, achieving a coating effect on the silica aerogel. Furthermore, 5-(palmitate) isophthalic acid contains long aliphatic carbon chains, which are chemically bonded to the PET-grafted silica aerogel. Further melt blending with polyethylene resin and polyethylene terephthalate yields a PET-PE composite material. Due to the grafting of these long aliphatic carbon chains onto the silica aerogel surface... The grafting of polyethylene terephthalate (PET) molecular chains into silica aerogels ensures excellent interfacial compatibility between the silica aerogel and the PET in the composite material. Furthermore, the PET-grafted silica aerogels chemically bond long aliphatic carbon chains similar to those in polyethylene resin, resulting in excellent interfacial compatibility between the silica aerogel and the PE resin in the composite material. This also improves the dispersibility of the aerogel. The excellent compatibility between silica aerogel and PET-PE composite materials has minimal impact on the mechanical properties of the composite material, allowing it to maintain good flexural and impact strength. Simultaneously, the aerogel is uniformly dispersed within the composite matrix, forming a continuous thermal insulation network, reducing the thermal conductivity of the composite material, and providing excellent thermal insulation performance.

[0057] Compared to Example 1, the polyethylene terephthalate and silica aerogel of Comparative Example 1 do not contain amino groups and cannot react with 5-(palmitate) isophthalic acid. Polyethylene terephthalate was not grafted into the silica aerogel, and long aliphatic carbon chains were not chemically bonded in the PET-silica aerogel. This resulted in poor compatibility between the PET-silica aerogel and PET and PE polyethylene resins, poor dispersibility in the composite material, and a significant impact on the mechanical properties of the composite material, with low flexural strength and impact strength, high thermal conductivity, and poor thermal insulation performance.

[0058] Comparative Example 2's polyethylene terephthalate does not contain amino groups. Grafting polyethylene terephthalate into silica aerogel results in poor compatibility between PET-silica aerogel and PET in the composite material. The composite material has lower flexural strength and impact strength than Example 1, and higher thermal conductivity, resulting in poor thermal insulation performance.

[0059] The silica aerogel in Comparative Example 3 does not contain amino groups, and it is impossible to graft polyethylene terephthalate into the silica aerogel via 5-(palmitate)isophthalic acid. This results in poor compatibility between the silica aerogel and the PET and PE polyethylene resins in the composite material, poor dispersion in the composite material, and a significant impact on the mechanical properties of the composite material. The flexural strength and impact strength are low, and the thermal conductivity is high, resulting in poor thermal insulation performance.

[0060] The isophthalic acid in Comparative Example 4 does not contain long aliphatic carbon chains, resulting in poor compatibility between the PET-grafted silica aerogel and the PE polyethylene resin in the composite material. This leads to lower flexural strength and impact strength compared to Example 1, as well as higher thermal conductivity and poorer thermal insulation performance.

[0061] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A preparation process for a heat-insulating and high-toughness PET-PE composite material, characterized in that, The preparation process includes: Step (1) Aminated polyethylene terephthalate, KH550-silica aerogel and 5-(fatty amide) isophthalic acid are added to a screw extruder and melt-blended and extruded to obtain PET grafted silica aerogel; Step (2) Add 10-25 parts by weight of polyethylene terephthalate, 75-90 parts by weight of polyethylene resin, 5-30 parts by weight of PET grafted silica aerogel, and 0.2-0.3 parts by weight of antioxidant to a screw extruder, melt-blend and extrude, and pelletize to obtain a heat-insulating and high-toughness PET-PE composite material. The amount of amino-modified polyethylene terephthalate in (1) is 100 parts by weight, KH550-silica aerogel is 20-40 parts by weight, and 5-(fatty amide) isophthalic acid is 3-8 parts by weight. The preparation process of the 5-(fatty amide) isophthalic acid includes: adding 5-amino isophthalic acid, fatty acyl chloride, and catalyst in a molar ratio of 1:(1-1.4):(3-3.6) to a solvent, stirring the reaction at 20-30℃ for 18-24h, distilling under reduced pressure, and recrystallizing the product to obtain 5-(fatty amide) isophthalic acid. The structural formula of the fatty acyl chloride is C. n H 2n+1 COCl, n is 11-17.

2. The preparation process of the thermal insulation and high-toughness PET-PE composite material according to claim 1, characterized in that, The temperature of sections 1-5 of the screw extruder in (1) is 240-270℃, and the screw speed is 30-60r / min.

3. The preparation process of the thermal insulation and high-toughness PET-PE composite material according to claim 1, characterized in that, The temperature of sections 1-5 of the screw extruder in (2) is 180-265℃, and the screw speed is 50-100r / min.

4. The preparation process of the thermal insulation and high-toughness PET-PE composite material according to claim 1, characterized in that, The preparation process of the aminated polyethylene terephthalate includes: molding polyethylene terephthalate into a film, placing it in a plasma treatment instrument, and performing plasma treatment in an ammonia atmosphere. The ammonia flow rate is 100-200 mL / min, the discharge power is 50-80 W, and the treatment time is 10-20 min to obtain aminated polyethylene terephthalate.

5. The preparation process of the thermal insulation and high-toughness PET-PE composite material according to claim 1, characterized in that, The preparation process of the KH550-silica aerogel is as follows: KH550 is added to water, ultrasonically treated in an ultrasonic instrument and heated to 45-55℃, silica aerogel is added, the reaction is carried out for 10-20 minutes, dried to remove water, washed and dried to obtain KH550-silica aerogel.

6. The preparation process of the thermal insulation and high-toughness PET-PE composite material according to claim 1, characterized in that, The solvent is N,N-dimethylformamide or tetrahydrofuran.

7. The preparation process of the thermal insulation and high-toughness PET-PE composite material according to claim 1, characterized in that, The catalyst is pyridine or 4-dimethylaminopyridine.

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