CN111793333A

CN111793333A - Preparation method of PET foam core material for wind power blade

Info

Publication number: CN111793333A
Application number: CN202010778432.0A
Authority: CN
Inventors: 唐子成
Original assignee: Anhui Guocheng Shunfeng Wind Power Generation Co ltd
Current assignee: Anhui Guocheng Shunfeng Wind Power Generation Co ltd
Priority date: 2020-08-05
Filing date: 2020-08-05
Publication date: 2020-10-20

Abstract

The invention discloses a preparation method of a PET foam core material for a wind power blade, which belongs to the technical field of high polymer materials, wherein the PET foam core material prepared by the preparation method is a thermoplastic renewable polymer foam material, is simple to operate and low in investment, and does not need to select supercritical gas as a foaming agent, so that the high cost of equipment and critical fluid is reduced, the toughness is improved due to the introduction of a foaming agent, and the PET foam core material has remarkable popularization and application values, is clean in process, excellent in comprehensive mechanical property, stable in chemical property, good in heat resistance, good in size stability, fatigue resistance and processability, and can be applied to the core material for the wind power blade.

Description

Preparation method of PET foam core material for wind power blade

Technical Field

The invention belongs to the technical field of high polymer materials, and particularly relates to a preparation method of a PET foam core material for a wind power blade.

Background

The sandwich material is one of key materials of the wind power blade, and in order to increase the structural rigidity, prevent local instability and improve the load resistance of the whole blade, sandwich structures are generally adopted at the front edge, the rear edge, the shearing part and the like of the blade. At present, the mainstream sandwich materials for wind power blades are cross-linked PVC foam and balsa wood. The core material is mainly used as a core layer of a glass fiber sandwich structure, the weight of the blade is reduced while the rigidity of the blade is improved, and the core material is used at a skin of a fan blade shell and a structural beam in the middle of the blade. The currently used foam core materials include styrene acrylonitrile foam, polyethylene terephthalate foam, polystyrene foam, polymethyl imide foam materials and the like, but the foam core materials are not balanced in performance and are less used due to higher price. The properties of each foam are different due to different materials and forming processes, and the properties of the foam core material are directly influenced. The technical defects of the mainstream foam core material on the market at present are low bonding strength with a composite material, poor material quality, poor heat resistance of the material, poor chemical resistance, low toughness, poor fatigue resistance and the like. The blade core material is a key material of the wind power blade. The core material is usually installed at the front edge, the rear edge, the web plate and other parts of the blade, and a sandwich structure is generally adopted to increase the structural rigidity, prevent local instability and improve the load resistance of the whole blade. The core material accounts for 10-15% of the cost of the blade material, and balsa wood and PVC foam are main varieties of the blade core material, wherein balsa wood is used as a main material, and PVC foam is used as an auxiliary material. The balsa wood depends on the ecuador, and more than 90 percent of balsa wood is from the ecuador, the production period is 5-7 years, and the price reaches more than ten thousand yuan per cubic meter when the demand is tight and the price rises. When the core material is used, resin is absorbed into the interior of the existing core material, thereby increasing the weight of the blade. For example, chinese patent CN2017100922347 discloses a PVC foam core material and a production process thereof, but the prepared PVC foam core material has low density and high strength, can be used in the industrial fields of wind turbine blades and the like, uses a product obtained by crosslinking isocyanate and polyvinyl chloride, and cannot avoid the above-mentioned defects. However, the existing core material has good heat resistance, can be recycled by 100 percent, has less pollution and lower cost, the permeability in five years in the future is doubled from the third large core material to the first large core material to replace balsa wood and PVC foam, people actively explore the preparation method of the PET foam core material, for example, chinese patent CN2017107063109 discloses a method for preparing PET foam by soaking and foaming sponge, wherein a sponge body dispersed with PET powder is sintered, but the sponge body cannot be sintered and removed, the obtained sponge is only dispersed with PET, but not PET foam core material, Chinese patent CN2016103016439 discloses a method for preparing a wind power generation blade sandwich PET foam material, supercritical foaming is utilized, however, the equipment cost is high, the process is complex, and a person skilled in the art needs to develop a preparation method of the PET foam core material for the wind power blade urgently to meet the existing use requirement and performance requirement.

Disclosure of Invention

The invention aims to provide a preparation method of a PET foam core material for a wind power blade aiming at the existing problems.

A preparation method of a PET foam core material for a wind power blade comprises the following steps:

(1) weighing 100-105 parts of PET resin slices dried for 3-5 hours at 135-140 ℃, 0.1-0.4 part of stabilizer, 0.2-0.4 part of lubricant, 3-5 parts of gel filler and 20-35 parts of capsule according to parts by weight, and uniformly mixing for 10-20 min in a high-speed mixer to obtain a mixture; (2) heating a charging barrel of an extruder to 240-260 ℃, plastifying and plasticizing the mixture obtained in the step (1) through the extruder, wherein the rotating speed of a screw of the extruder is 30-50 r/min, the temperature of a machine head is 220-230 ℃, and extruding to obtain a PET core material; (3) and soaking the obtained PET core material in hot water of 60-75 ℃ for 120-150 h, drying at 135-140 ℃ for 3-5 h, heating to 235-240 ℃ and curing for 1-2 h to obtain the PET foam core material.

The microcapsule technology is a packaging technology for coating solid, liquid or gaseous trace substances in a polymer wall shell to form micro particles, and can achieve the purposes of powdering, isolation, slow release, controlled release and stable preservation on the premise of keeping the original characteristics of core materials. In recent years, researches are carried out in the fields of flame retardance, corrosion resistance, fragrance release, thermochromic, phase change energy storage and the like, but the commercialized products are few, and the preparation method has fresh application in the preparation of foaming materials.

The capsule is a polyester microcapsule which consists of a water-soluble template and a foaming agent and is coated by a core material.

Further, the vesicle agent in the step (1) is a polyester microcapsule, and the specific preparation method comprises the steps of feeding sodium polyacrylate, polyvinylpyrrolidone, 5-phenyltetrazole, barium azodicarboxylate, benzenesulfonylhydrazide and trihydrazinotriazine according to the mass ratio of 11-13: 0.4-0.6: 5-7: 2-4: 3-5: 1-2, uniformly stirring at a constant temperature of 30-35 ℃ to obtain a core material mixture, dispersing 10-12 parts of the core material mixture and 20-22 parts of terephthaloyl chloride into 500-600 parts of a chlorinated biphenyl solvent, stirring to form a solution, emulsifying and dispersing the solution into 600-700 parts of a sodium bicarbonate aqueous solution with a mass fraction of 0.6-1%, adding 50-70 parts of an ethylene glycol solution with a mass fraction of 6-8% into the sodium bicarbonate aqueous solution under continuous stirring, stirring at a speed of 600-800 r/min, and stirring at a temperature of 45-50 ℃ for 30-45 min, filtering, washing and drying for 1-2 h at 85-90 ℃ to obtain the product.

Further, the stabilizer in the step (1) is one or more of phosphoryl acetic acid triphosphonate, a light stabilizer 3638 and o-phenylphenol.

Further, the gel filler in the step (1) is one or more of silica aerogel, zirconia aerogel and alumina aerogel.

Further, the lubricant in the step (1) is one or more of ethylene bisricinoleic acid amide, molybdenum disulfide and pentaerythritol stearate.

Further, ultrasonic treatment is carried out while the PET core material in the step (3) is soaked, and the ultrasonic treatment is carried out at 10-20 kHz.

The soaking and the generating treatment enable the sodium polyacrylate and the polyvinylpyrrolidone in the microcapsules to be dissolved out in the microporous foaming PET, so that the hollowing of the polyester microcapsules is realized.

The invention has the beneficial effects that:

the invention utilizes polyester microcapsules containing foaming agent and soluble polymer as a carrier for preparing PET foaming core material, the microcapsules are synthesized by polyester interfacial polymerization, the microcapsules are the same as a matrix PET component, can be uniformly dispersed in the PET core material, have good compatibility, avoid the agglomeration of the foaming agent and the soluble polymer, use soluble polymer sodium polyacrylate and polyvinylpyrrolidone which can be dissolved in water and have surface activity, can promote the forming of the polyester microcapsules in the interfacial polymerization process, enable the microcapsules to wrap the foaming agent, have a cavity structure, can further improve the cavity rate of the PET core material, use water-soluble polymer and foaming agent as core materials, also form the precondition that the cavities formed by the polyester microcapsules are uniformly distributed on the PET core material to improve the performance of the foaming core material, and the foaming agent and water-soluble polymer form polyester liquid drops in the interfacial polymerization reaction process, the regenerated microcapsule promotes the forming by the emulsification of the water-soluble polymer, the sodium bicarbonate plays a role in neutralization, the size of the polyester microcapsule can be adjusted by controlling the component proportion, the emulsification effect and the rotating speed, the water-soluble polymer is gradually separated from the PET core material by hot water ultrasonic soaking, the original polyester microcapsule forms a cavity, the density of the core material is further reduced, the foaming agent realizes the slow release effect of foaming due to the effect of the polyester microcapsule, the foaming agent decomposes gas for foaming along with the rise of the temperature, and after the foaming agent is soaked in the hot water, part of the residual foaming agent is further cured and plays a foaming role again, so compared with the pure foaming agent, the foaming agent can be quickly foamed, the foaming degree is more uniform and consistent, and the foaming agent is attached with the cavity effect of the polyester microcapsule, the toughness and the impact property of the PET core material can be further improved, and the density of the core material is reduced to a certain extent, the strength of the core material is further improved by adopting the gel filler, and the density of the core material is not obviously increased.

Compared with the prior art, the invention has the following advantages:

the invention discloses a preparation method of a PET foam core material for wind power blades, which adopts a vesicle agent with polyester microcapsules as a main component, not only has the function of uniform foaming, but also can form a cavity bag, the selected foaming agent has the function of foaming at a step temperature, the foaming temperature is higher, and the forming of the polyester microcapsules is facilitated, the PET is mainly used for manufacturing synthetic fibers, films and beverage bottles in the past, the microcapsules are applied to flame retardance, fertilizers and the like in the past, but the preparation method is different from the application, the PET foam core material prepared by the preparation method disclosed by the invention is a thermoplastic renewable polymer foaming material, compared with the existing methods such as critical fluid foaming and the like, the operation is simpler, the investment is smaller, and supercritical gas is not required to be selected as the foaming agent, so that the cost of equipment and critical fluid is reduced, the preparation method has remarkable popularization and application values, the process is clean, and the comprehensive mechanical properties are excellent, the PET foam has the advantages of stable chemical property, good heat resistance, good dimensional stability, good fatigue resistance and good machinability, can be applied to core materials for wind power blades, has good heat resistance and mechanical strength due to the fact that the toughness is improved by the introduction of the capsule, can be recycled, has good environmental protection performance, and can be widely applied to the core materials of the PET foam for the wind power blades.

Detailed Description

The invention is illustrated by the following specific examples, which are not intended to be limiting.

Example 1

PET resin slices are purchased from RE5073 of Du Pont, nano-silica aerogel of Hebei Taogo Nanko, benzenesulfonylhydrazide of Jiaxing Cheng Yi chemical industry, barium azodicarboxylate permanently synthesized, 5-phenyltetrazole of Zhejiang Tujia graphics strengthening chemical industry, and sodium polyacrylate is purchased from industrial commercial product of stannionless Feng Min environmental protection viscosity-average molecular weight 6000.

Firstly, preparing polyester microcapsules coated with water-soluble polymers and foaming components through interfacial polymerization, feeding sodium polyacrylate, polyvinylpyrrolidone, 5-phenyltetrazole, barium azodicarboxylate, benzenesulfonyl hydrazide and trihydrazinotriazine according to the mass ratio of 13: 0.6: 7: 4: 5: 2, uniformly stirring at the constant temperature of 35 ℃ to obtain a core material mixture, dispersing 12 parts of the core material mixture and 22 parts of terephthaloyl chloride into 600 parts of chlorinated biphenyl solvent by weight, stirring to form a solution, emulsifying and dispersing the solution into 600 parts of sodium bicarbonate aqueous solution with the mass fraction of 1%, then adding 70 parts of glycol solution with the mass fraction of 8% into the sodium bicarbonate aqueous solution under the condition of continuous stirring, stirring at the temperature of 800r/min and 45min, filtering, washing at the temperature of 90 ℃, drying for 2 hours to obtain the polyester microcapsules, and secondly, wherein the polyester microcapsules are prepared by using sodium polyacrylate, polyvinylpyrrolidone, 5-phenyltetrazole, barium azodicarboxylate, benzenesulfonyl hydrazide and trihydrazinotriazine, and trihydrazinotri, Weighing the following raw materials in parts by weight, drying PET resin slices for 5 hours at 140 ℃, and uniformly mixing 105 parts of a stabilizer phosphoryl acetic acid triphosphite, 0.4 part of an ethylene bisricinoleic acid amide lubricant, 5 parts of a silicon dioxide aerogel filler and 20 parts of a capsule agent in a high-speed mixer for 20 minutes to obtain a mixture; thirdly, heating the charging barrel of the extruder to 240 ℃, plastifying and plasticizing the mixture by the extruder, wherein the rotating speed of a screw of the extruder is 50r/min, the temperature of a machine head is 230 ℃, and extruding to obtain the PET core material; and fourthly, soaking the obtained PET core material and carrying out ultrasonic treatment at the same time, wherein the ultrasonic treatment is 20kHz, drying the PET core material for 3 hours at 135 ℃ after the PET core material is soaked in hot water at 75 ℃ for 120 hours, and heating to 235 ℃ for curing for 1 hour to obtain the PET foam core material.

Example 2

PET resin chips were purchased from RE5073 from Du Pont, alumina aerogel was purchased from Beigaer-Al2O3-7, Benzenesulfonylhydrazide in Jiaxing Cheng Yi chemical industry, barium azodicarboxylate in Yongxing chemical industry, 5-phenyltetrazole in Zhejiang graphics chemical industry, and sodium polyacrylate was purchased from an industrial commercial product having a viscosity-average molecular weight of 6000 for Ningfengmin-free environmental protection.

Firstly, preparing polyester microcapsules which are coated with water-soluble polymers and foaming components through interfacial polymerization, feeding sodium polyacrylate, polyvinylpyrrolidone, 5-phenyltetrazole, barium azodicarboxylate, benzenesulfonyl hydrazide and trihydrazinotriazine according to the mass ratio of 11: 0.4: 5: 2: 3: 1, uniformly stirring at the constant temperature of 30 ℃ to obtain a core material mixture, dispersing 10 parts of the core material mixture and 20 parts of terephthaloyl chloride into 500 parts of chlorinated biphenyl solvent by weight, stirring to form a solution, emulsifying and dispersing the solution into 600 parts of a sodium bicarbonate aqueous solution with the mass fraction of 1%, then adding 70 parts of an ethylene glycol solution with the mass fraction of 8% into the sodium bicarbonate aqueous solution under continuous stirring, stirring at 800r/min and at 50 ℃ for 45min, filtering, washing and drying at 90 ℃ for 1h to obtain the polyester microcapsules; secondly, weighing the following raw materials in parts by weight, drying the PET resin slices for 5 hours at 140 ℃, uniformly mixing 105 parts of PET resin slices, 0.4 part of o-phenylphenol serving as a stabilizer, 0.4 part of pentaerythritol stearate lubricant, 5 parts of silica aerogel filler and 20 parts of a capsule agent in a high-speed mixer for 10 minutes to obtain a mixture; thirdly, heating the charging barrel of the extruder to 240 ℃, plastifying and plasticizing the mixture by the extruder, wherein the rotating speed of a screw of the extruder is 50r/min, the temperature of a machine head is 230 ℃, and extruding to obtain the PET core material; and fourthly, soaking the obtained PET core material and carrying out ultrasonic treatment at the same time, wherein the ultrasonic treatment is 20kHz, drying the PET core material for 5 hours at 140 ℃ after the PET core material is soaked in hot water at 75 ℃ for 150 hours, and heating to 240 ℃ for curing for 2 hours to obtain the PET foam core material.

Comparative example 1

In this comparative example, compared with example 2, in the first step, the sodium polyacrylate component was omitted, except that the process steps were the same.

Comparative example 2

In this comparative example, compared to example 2, in the first step, the polyvinylpyrrolidone component was omitted, except that the process steps were the same.

Comparative example 3

This comparative example compares to example 2 in the fourth step, the ultrasonication was omitted except that the process steps were otherwise the same.

Comparative example 4

This comparative example compares to example 2 in the fourth step, the hot water soak is omitted, except that the process steps are the same.

The performance test of the wind power blade PET foam core materials of the embodiments 1-2 and the comparative examples 1-4 is carried out, and the test results are shown in Table 1

TABLE 1 Performance test results of the PET foam core materials for wind power blades of examples 1 to 2 and comparative examples 1 to 4

[0001]Item

[0002]Example 1

[0003]Example 2

[0004]To pairRatio 1

[0005]Comparative example 2

[0006]Comparative example 3

[0007]Comparative example 4

[0008]Compressive strength MPa

[0009] 1.76

[0010] 1.73

[0011] 1.75

[0012] 1.73

[0013] 1.73

[0014] 1.86

[0015]Apparent density g/cm³

[0016] 114.5

[0017] 115.0

[0018] 118.5

[0019] 116.0

[0020] 118.0

[0021] 123.5

[0022]Compressive modulus GPa

[0023] 68.8

[0024] 67.9

[0025] 68.6

[0026] 68.4

[0027] 67.8

[0028] 68.4

[0029]Shear deformation%

[0030] 5.7

[0031] 5.5

[0032] 5.9

[0033] 5.6

[0034] 5.7

[0035] 5.8

[0036]Tensile strength MPa

[0037] 2.5

[0038] 2.6

[0039] 2.4

[0040] 2.3

[0041] 2.4

[0042] 2.2

[0043]Tensile modulus GPa

[0044] 87.7

[0045] 88.1

[0046] 84.3

[0047] 85.5

[0048] 86.9

[0049] 85.2

[0050]Shear strength MPa

[0051] 0.81

[0052] 0.82

[0053] 0.84

[0054] 0.82

[0055] 0.83

[0056] 0.80

Note: measurements to determine the apparent density (volume) of ISO845-2006 foams and rubbers were made with reference to the following standards and methods; determination of compression property of ISO844-2014 rigid foam; determination of the shear strength of the rigid foam plastics according to ISO 1922-2018; ASTM C297-2004 sandwich Flat tensile Strength Standard test method.

Claims

1. A preparation method of a PET foam core material for a wind power blade is characterized by comprising the following steps:

2. The preparation method of the PET foam core material for the wind power blade according to claim 1, wherein the capsule is a polyester microcapsule, and the preparation method comprises the steps of feeding sodium polyacrylate, polyvinylpyrrolidone, 5-phenyltetrazole, barium azodicarboxylate, benzenesulfonylhydrazide and trihydrazinotriazine at a mass ratio of 11-13: 0.4-0.6: 5-7: 2-4: 3-5: 1-2, uniformly stirring at a constant temperature of 30-35 ℃ to obtain a core material mixture, dispersing 10-12 parts by weight of the core material mixture and 20-22 parts by weight of terephthaloyl chloride in 500-600 parts by weight of a biphenyl chloride solvent, stirring to form a solution, emulsifying and dispersing the solution in 600-700 parts by weight of a sodium bicarbonate solution with a mass fraction of 0.6-1%, adding 50-70 parts by weight of an ethylene glycol solution with a mass fraction of 6-8% into the sodium bicarbonate solution under continuous stirring, stirring for 30-45 min at 45-50 ℃ at 600-800 r/min, filtering, washing, and drying for 1-2 h at 85-90 ℃ to obtain the product.

3. The preparation method of the PET foam core material for the wind power blade according to claim 1, wherein the stabilizer in the step (1) is one or more of phosphoryl acetic acid triphosphonate, a light stabilizer 3638 and o-phenylphenol.

4. The preparation method of the PET foam core material for the wind power blade according to claim 1, wherein the gel filler in the step (1) is one or more of silica aerogel, zirconia aerogel and alumina aerogel.

5. The method for preparing the PET foam core material for the wind power blade according to claim 1, wherein the lubricant in the step (1) is one or more of ethylene bisricinoleic acid amide, molybdenum disulfide and pentaerythritol stearate.

6. The epoxy resin foam according to claim 1, wherein the PET core material of step (3) is soaked and simultaneously subjected to ultrasonic treatment, and the ultrasonic treatment is performed at 10-20 kHz.