CN104817830A - Aromatic polyester foaming microcellular foaming material and preparation method thereof - Google Patents

Abstract

The invention discloses an aromatic polyester microcellular foaming material, which is prepared from an aromatic polyester composition through a foaming process. The aromatic polyester composition includes 100 parts by weight of aromatic polyester, sorbitol benzylidene derived 0.5-5 parts by weight of compound, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, and 0-2 parts by weight of cell nucleating agent; the apparent density of the aromatic polyester microcellular foaming material is 0.05-1.10g/cm ³ , the closed cell rate is not less than 80%. The invention also discloses various preparation methods of the aromatic polyester microcellular foaming material. The aromatic polyester microcellular foaming material of the invention has the characteristics of wide foaming temperature range, easy process control, small and uniform cell size, and excellent heat resistance and mechanical properties of the product.

Description

A kind of aromatic polyester microporous foam material and preparation method thereof

technical field

The invention belongs to the field of polymer materials, and in particular relates to an aromatic polyester foam material and a preparation method thereof.

Background technique

Foamed plastic is a composite material filled with a large number of air bubbles based on plastic, so it has excellent properties such as light weight, material saving, high specific strength, low thermal conductivity, excellent heat and sound insulation, and ability to absorb impact loads, so it is widely used. Used as packaging, heat insulation, anti-freezing and heat preservation, cushioning and anti-vibration, sound-absorbing materials, it has been widely used in construction, transportation, daily necessities, packaging, aerospace, navigation, national defense and other fields. Traditional ones such as polyurethane foam (PU), polyethylene foam (PE) and polystyrene foam (PS), etc., have certain deficiencies in the material itself and processing methods, such as polyurethane foam will release isocyanate during the preparation process, etc. Harmful residues to the human body, and the foamed polyurethane is difficult to recycle. Due to its low temperature resistance, polystyrene foam is limited in its application fields. Polyethylene foam has the disadvantages of poor mechanical properties and low heat resistance. Therefore, people have been devoting themselves to the development of high-performance foamed plastics to broaden the application fields of foamed materials and meet the increasing requirements for material performance in the development of society and technology.

Aromatic polyester has excellent heat resistance and mechanical properties. Compared with traditional foam plastics, it has good dimensional stability at high temperature, excellent mechanical properties and fatigue resistance, low smoke, flame retardant, non-toxic, low water absorption High efficiency, good gas barrier properties, and recyclability, etc., have broad application prospects in the fields of electronics industry, cushioning packaging, building materials, transportation, and wind power generation.

Chinese invention patent application CN201280042030.8 discloses an aromatic polyester-based resin foam particle for in-mold foam molding and a preparation method thereof. After the mixture is evenly mixed, it is extruded and foamed through a die, cooled and cut into pellets, and the in-mold molding method can be used for secondary foam molding products. The bulk density of the expandable particles is 0.05-0.7g/cm ³ , and the crystallinity Less than 15%. In order to increase the closed cell ratio of expandable particles, use aromatic polyester with an intrinsic viscosity of 0.8-1.1, and add 0.01-5 parts by weight of a crosslinking agent to increase the molecular weight of the polyester resin so that its Z-average molecular weight is higher than 2X10 ⁵ . In order to better perform secondary foaming in the technical solution disclosed in this invention, the crystallinity of the expandable particles is controlled to be low (less than 15%), the heat resistance of the foamed product is reduced, and the aromatic polyester cannot be fully utilized. performance.

U.S. Patent No. 5,679,295A discloses a method for preparing PET foamed products by extruding a composite foaming agent. The method uses a PET resin with an intrinsic viscosity greater than 0.8dl/g, at least 50mol% of heptane, octane or cyclopentane and Butane, tetrafluoroethane, CO2, etc. are used as composite foaming agents, and the dissolution pressure of the foaming agent in PET at the foaming temperature is adjusted to be lower than 4.5MPa. At the glass transition temperature of PET, the dissolution pressure is lower than 0.1 MPa. The technical solution disclosed in the invention uses a multi-component foaming agent, the process is complex, and the control pressure during foaming is relatively low, resulting in a large pore size of the foamed product and reduced toughness and thermal conductivity of the material.

Chinese invention patent application CN102504498A discloses a foamed PET sheet and its preparation method. The foamed sheet consists of 100 parts by weight of PET resin, 0.1-10 parts by weight of nucleating agent, and 0.1-10 parts by weight of cell stabilizer. The foaming agent is composed of 1.5-1.8 parts by weight, mixed by an extruder, extruded and foamed. The technical solution disclosed in this patent uses a chemical foaming agent as an auxiliary foaming agent. The small molecules produced by the decomposition of the chemical foaming agent are likely to cause thermal degradation of polyester, which increases the complexity of the process and lower product performance. The apparent density is high.

Chinese invention patent application CN101544812 discloses a foamed CPET sheet and its preparation method. The sheet is composed of 100 parts by weight of PET, 0.1-40 parts by weight of foaming aid, and 0.1-5 parts by weight of foaming agent are mixed uniformly. , extrusion foam molding. The foaming aid is composed of 0.1-30 parts by weight of ethylene-acrylate-glycidyl methacrylate terpolymer or acrylate substances with core-shell structure, 0.1-10 parts by weight of highly active multifunctional substances, 0.3 parts by weight - Prepared by uniformly mixing 10 parts by weight of a crystal nucleating agent and 10-100 parts by weight of a carrier resin.

In the prior art, in order to overcome the disadvantages of low melt viscosity of aromatic polyester, which is difficult to maintain the cell structure, and easily cause cell collapse and merging, the viscosity of PET is increased by adding a cross-linking agent, but this technology is easy to cause cross-linking structure, and the residual cross-linking agent is not good for the recycling of products. On the other hand, the crystallization rate of aromatic polyester is slow, the foamed products are difficult to shape, and it is difficult to obtain microcellular PET foamed products.

Contents of the invention

The object of the present invention is to overcome the above-mentioned shortcomings in the prior art, and provide an aromatic polyester microcellular foaming material and its preparation method, which has a wide foaming temperature range, easy process control, low production cost, and excellent product quality. The characteristics of heat resistance and mechanical properties.

In order to realize the purpose of the present invention, the present invention provides following technical scheme:

The invention provides an aromatic polyester microporous foaming material, which is prepared from an aromatic polyester composition through a foaming process. The aromatic polyester composition includes 100 parts by weight of aromatic polyester and sorbitol benzylidene derivatives 0.5-5 parts by weight, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, and 0-2 parts by weight of cell nucleating agent. The apparent density of the aromatic polyester microcellular foaming material is 0.05-0.50 g/cm ³ , and the closed cell ratio is not less than 80%.

According to one embodiment of the preparation method of an aromatic polyester microcellular foaming material of the present invention, it comprises: (1) 100 parts by weight of aromatic polyester, 0.5-5 parts by weight of sorbitol benzylidene derivative, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, and 0-2 parts by weight of cell nucleating agent, mixed in proportion into an aromatic polyester composition and then added to the extruder; (2) adding Inject a physical foaming agent into the extruder, the injection amount of the physical foaming agent is 0.1-10% of the total weight of the aromatic polyester composition, and mix uniformly in the extruder; (3 ) Cooling the melt of the aromatic polyester composition containing the physical foaming agent to 220-250° C., the die pressure is greater than 3 MPa, and the aromatic polyester microcellular foaming material is obtained through die foaming and shaping.

According to another embodiment of the preparation method of an aromatic polyester microcellular foaming material of the present invention, it comprises: (1) adding 100 parts by weight of aromatic polyester and 0.5-5 parts by weight of sorbitol benzylidene derivative , 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent, 0.1-5 parts by weight of chemical foaming agent, mixed in proportion and added to the extruder, It is melted under the action of heating and screw shear plasticization, and the chemical blowing agent decomposes to release volatile gas, which is uniformly mixed in the extruder; (2) the aromatic polystyrene containing the chemical blowing agent The ester melt mixture is extruded through a die and cooled and shaped to obtain an aromatic polyester microcellular foaming material.

According to another embodiment of the preparation method of an aromatic polyester microcellular foaming material of the present invention, it includes (1) mixing 100 parts by weight of aromatic polyester, 0.5-5 parts by weight of sorbitol benzylidene derivatives, 0.1-0.3 parts by weight of oxygen agent, 0-2 parts by weight of chain extender, and 0-2 parts by weight of cell nucleating agent, mixed in proportion and added to the injection molding machine, and melted under the action of heating and screw shear plasticization (2) sending the physical foaming agent into the aromatic polyester polymer melt in the injection molding machine, the addition of the physical foaming agent is 0.1-1% of the total weight of the aromatic polyester composition , mixed uniformly in the injection molding machine; (3) injecting the aromatic polyester melt mixture containing the physical foaming agent into the mold through the injection nozzle, cooling and shaping to obtain the aromatic polyester microcellular foaming material.

Another embodiment of the preparation method of an aromatic polyester microcellular foaming material according to the present invention comprises: (1) 100 parts by weight of aromatic polyester, 0.5-5 parts by weight of sorbitol benzylidene derivative, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent, and 0.1-1 part by weight of chemical foaming agent are mixed in proportion and added to the injection molding machine. Melting under the action of screw shear plasticization; (2) injecting the aromatic polyester melt mixture containing the chemical foaming agent into the mold through the injection nozzle, cooling and shaping to obtain the aromatic polyester microcellular foaming material .

Description of drawings

Figure 1 is a graph showing the relationship between the melt storage modulus and the frequency of PET with different contents of DMDBS added at 260°C.

Fig. 2 is a graph showing the relationship between complex viscosity and frequency of PET with different content of DMDBS added at 260°C.

FIG. 3 is a scanning electron micrograph of PET microporous foam obtained in Example 1.

FIG. 4 is a scanning electron micrograph of PET microporous foam obtained in Comparative Example 1.

Detailed ways

The aromatic polyester microcellular foaming material provided by the present invention is prepared from an aromatic polyester composition through a foaming process. The aromatic polyester composition includes 100 parts by weight of aromatic polyester, 0.5 parts by weight of sorbitol benzylidene derivative -5 parts by weight, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, and 0-2 parts by weight of cell nucleating agent.

Aromatic polyester refers to a polymer obtained by polymerization reaction of aromatic dicarboxylic acid and diol, and its macromolecular main chain structure contains a benzene ring structure, such as polyethylene terephthalate, polyethylene terephthalate Trimethylene diformate, polybutylene terephthalate, etc., preferably polyethylene terephthalate. In addition, the aromatic polyester resin may contain a third copolymerization component, such as resorcinol, in addition to the aromatic dicarboxylic acid and diol. The aromatic polyester can be a blend of one or more aromatic polyesters. Homopolymer or copolymer of polyethylene terephthalate is more suitable. It can also be polyester for general fiber or polyester for bottle, or recycled polyester for bottle through chain extension modification.

The intrinsic viscosity of aromatic polyester is not less than 0.8dl/g, and the intrinsic viscosity of more suitable aromatic polyester is not less than 1.0dl/g. The intrinsic viscosity is tested according to the method of GB/T14190-2008 (solvent adopts phenol/tetrachloroethane ( Mass ratio 50/50)). The intrinsic viscosity of the aromatic polyester is too low to cover the growing air bubbles, which may easily cause the air bubbles to merge or rupture.

Sorbitol benzylidene derivatives refer to benzylidene sorbitol derivatives obtained by the condensation reaction of sorbitol and aldehyde compounds, and its molecular formula is as follows:

R1 and R2 represent a hydrogen atom, an alkyl or alkoxy group having 1 to 4 carbon atoms, a hydroxyl group or a halogen-containing alkyl group. Commonly used ones include 2,4-O-(3,4-dimethylbenzylidene)-D-sorbitol (DMDBS), dibenzylidene-sorbitol (DBS), p-methylbenzylidene sorbitol (DMBS). The present invention is more suitable for selecting sorbitol compound with higher thermal stability, and its thermal decomposition temperature is not lower than 300°C, preferably not lower than 320°C, and the thermal decomposition temperature is tested by thermal weight loss method, and the atmosphere is air.

After a lot of experimental research, the inventors found that the sorbitol benzylidene derivatives can self-assemble into a nanofiber network through hydrogen bonds in the aromatic polyester melt. The nanofiber network can form physical entanglement points with the aromatic polyester macromolecular chains to improve the melt viscosity and melt elasticity of the aromatic polyester, as shown in FIGS. 1 and 2 . Figures 1 and 2 are the rotational rheological test results of PET melts with different 2,4-O-(3,4-dimethylbenzylidene)-D-sorbitol (DMDBS) contents at 260°C, Figure 1 It is the storage modulus-frequency sweep curve, and Fig. 2 is the complex viscosity-frequency sweep curve. It can be seen from Figure 1 that when the DMDBS content is 0, the PET melt exhibits obvious frequency dependence and liquid phase rheological behavior in the low frequency region. When the DMDBS content is 0.5wt% and above, the energy storage in the low frequency region The modulus increases obviously, and a plateau area appears, showing the behavior of solid material, which is the result of the increase of the elasticity of PET melt caused by the nanofiber network formed by the self-assembly of DMDBS. It can also be seen from Figure 2 that the complex viscosity of the PET melt added with DMDBS increases significantly in the low frequency region, and the viscosity decreases more with the change of frequency, indicating that the shear thinning is more obvious, which is due to the DMDBS self-assembled network and PET The macromolecular chains are entangled with each other, and the entanglement density of the system increases, which makes the shear thinning phenomenon more obvious. The increase of melt viscosity and melt elasticity of PET resin is conducive to the maintenance of the cell wall during the foaming process and avoids the merger and collapse of the cells.

In the present invention, the added amount of the sorbitol benzylidene derivative is 0.5-5% of the weight of the aromatic polyester, more preferably 1-3%. If the addition amount of sorbitol benzylidene derivatives is too small, the formed network structure is not enough to physically entangle with polyester, and has little effect on the melt viscoelasticity of polyester; if the addition amount of sorbitol benzylidene derivatives exceeds 5%, the formation of The nano-microfiber network structure will inhibit the growth of cells, and will cause the viscoelasticity of polyester melt to deteriorate, and the foaming process is not easy to control.

In order to increase the molecular weight of the aromatic polyester, a chain extender may also be added to the aromatic polyester composition of the present invention. The chain extender refers to a difunctional or multifunctional compound that can react with the carboxyl or hydroxyl at the end of the polyester. To increase the molecular weight of the polyester or to produce a branched structure. Including polybasic acid anhydrides such as pyromellitic dianhydride (PMDA), multifunctional epoxy resins such as tetrafunctional epoxy resins, bisoxazolines, etc. The content of the chain extender is 0-2% of the total weight of the aromatic polyester, preferably 0.3-1.0%.

The cell nucleating agent described in the present invention can be inorganic nucleating agent or organic nucleating agent, and inorganic nucleating agent comprises talcum powder, calcium carbonate, nano silicon dioxide, nano montmorillonite etc., and organic nucleating agent is Azodicarbonamide (AC) and the like are more suitable as one of talcum powder and azodicarbonamide. The added amount of the cell nucleating agent is 0-2% of the total weight of the aromatic polyester.

In order to avoid thermal degradation of polyester in high-temperature processing, 0.1-0.3 parts by weight of antioxidant are added to the aromatic polyester composition of the present invention, and the antioxidant is commonly used in polymer processing, such as four [β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, trade name Antioxidant 1010. Antioxidants can also be a compound of primary antioxidants and auxiliary antioxidants.

The apparent density of the aromatic polyester microcellular foaming material in the present invention is 0.05-1.10 g/cm3, preferably 0.10-0.80 g/cm3. The apparent density is tested according to the standard GB1033-86.

The closed cell rate of the aromatic polyester microporous foam material of the present invention is not more than 80%, and the closed cell rate of the foamed sample is measured by ULTRAFOAM 1000 (Quantachrome Instruments, USA).

In order to improve the flame retardancy of the material, flame retardants, including inorganic flame retardants and organic flame retardants, may also be added to the aromatic polyester microcellular foamed material in the present invention.

According to one embodiment of the preparation method of the aromatic polyester microcellular foaming material of the present invention, it adopts a physical extrusion foaming method, comprising: (1) 100 parts by weight of aromatic polyester, sorbitol benzylidene derivative 0.5-5 parts by weight, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent, mixed in proportion and added to the extruder, heated and screw sheared It is melted under the action of cutting and plasticizing; (2) The physical foaming agent is metered and pumped into the polymer melt in the extruder through the gas injection port installed on the extruder barrel, and the addition of the physical foaming agent The amount is 0.1-10% of the total weight of the aromatic polyester composition, uniformly mixed in the extruder; (3) reduce the temperature between the injection port of the blowing agent and the outlet of the machine head, and control the temperature of the melt at the machine head to 220-250°C, the melt pressure is not lower than 3MPa; the aromatic polyester melt mixture containing foaming agent is extruded through a die and cooled and shaped to obtain an aromatic polyester microcellular foaming material.

Here, the extruder is a common extrusion system for physical foaming, which can be single-screw extruder, twin-screw extruder or single-screw extruder in series with single-screw extruder, twin-screw extruder in series with single-screw extruder Extruder, the barrel of the extruder is provided with a blowing agent injection port.

Aromatic polyesters need to be sufficiently dried to remove moisture before being fed into the extruder to avoid thermal degradation in the extruder. It is more suitable to vacuum dry at 100°C for 12 hours, and then dry at 140°C for 12 hours. Other added ingredients also need to be pre-dried. The dried aromatic polyester and additives should be sealed and stored, or put into the extruder immediately. It is more suitable that the feeding device of the extruder has a drying device, or an inert gas sealing protection device.

The physical blowing agent is a low molecular weight alkane blowing agent such as pentane, butane, heptane, or an inert gas blowing agent such as carbon dioxide or nitrogen. Carbon dioxide and pentane are more suitable.

When foaming, a sheet die or plate die can be used to obtain an aromatic polyester foamed sheet or foamed board. After the die is exported, it is cooled and shaped by the cooling and shaping device to obtain the product with the desired cross-sectional shape.

According to another embodiment of the preparation method of the aromatic polyester microcellular foaming material of the present invention, it is a chemical extrusion foaming method, comprising: (1) 100 parts by weight of aromatic polyester, sorbitol benzylidene 0.5-5 parts by weight of derivatives, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent, 0.1-5 parts by weight of chemical foaming agent, mixed in proportion Then add it into the extruder, melt it under the action of heating and screw shear plasticization, the chemical foaming agent decomposes and releases volatile gas, and mixes evenly in the extruder; (2) Aromatic polystyrene containing foaming agent The ester melt mixture is extruded through a die and cooled and shaped to obtain an aromatic polyester microcellular foaming material.

The chemical foaming agent is an endothermic foaming agent, which may be azodicarbonamide, (4,4)-dioxybenzenesulfonyl hydrazide, p-toluenesulfonamide semicarbazide, and 5-phenyltetrazolium. More suitably is azodicarbonamide.

According to yet another embodiment of the preparation method of the aromatic polyester microcellular foaming material of the present invention, it adopts a physical foaming injection molding process, including: (1) 100 parts by weight of aromatic polyester, sorbitol benzylidene derivative 0.5-5 parts by weight, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent, mixed in proportion and added to the injection molding machine, heated and screw sheared Make it melt under the action of plasticization; (2) send the physical foaming agent into the polymer melt in the injection molding machine through the metering pump installed on the gas injection port on the barrel of the extruder, and the addition amount of the physical foaming agent is 0.1-1% of the total weight of the aromatic polyester composition, mixed uniformly in the injection molding machine; (3) injecting the aromatic polyester melt mixture containing the physical foaming agent into the mold through the injection nozzle, cooling and shaping to obtain the aromatic polyester composition Polyester microcellular foaming material. The physical blowing agent, such as carbon dioxide or nitrogen, is suitably nitrogen. The injection amount is 0.1-1% of the total weight of the aromatic polyester mixture, more preferably 0.3-0.6%.

According to yet another embodiment of the preparation method of the aromatic polyester microcellular foaming material of the present invention, it adopts a chemical foaming injection molding process, comprising: (1) 100 parts by weight of aromatic polyester, sorbitol benzylidene derivative 0.5-5 parts by weight, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent, 0.1-1 part by weight of chemical foaming agent, mixed in proportion and added to injection molding (2) inject the aromatic polyester melt mixture containing the chemical blowing agent into the mold through the injection nozzle, cool and shape it to obtain the aromatic polyester Ester microcellular foam material. The more suitable chemical foaming agent is azodicarbonamide, and the addition amount is 0.1-1% of the total weight of the aromatic polyester, more preferably 0.2-0.5%.

Example:

The technical solution of the present invention is described in detail through the following examples and comparative examples.

Example 1:

Raw material: polyethylene terephthalate (PET), intrinsic viscosity 0.80dl/g (according to GB/T14190-2008) test, solvent is phenol/1,1,2,2,-tetrachloroethane (mass ratio 50/50), Sinopec Yizheng Chemical Fiber Co., Ltd.; ,4-dimethylbenzylidene) sorbitol, referred to as DMDBS, thermal decomposition temperature 320 ℃, model ZC-3, Yantai Zhichu Synthetic Chemical Co., Ltd. The thermal decomposition temperature is measured by a thermogravimetric analyzer. The heating rate is 10°C/min. On the thermogravimetric curve, the maximum weight loss rate is the thermal decomposition temperature.

Antioxidant Irganox1010, Germany BASF company.

Talc powder, 1000 mesh, Beijing Liguoweiye Powder Material Co., Ltd.

Carbon dioxide, purity 99.5%, Beijing Oxygen Factory.

Foaming process: Pre-dry polyethylene terephthalate (PET), DMDBS, antioxidant, talcum powder, etc. The drying process is: PET, 100 ° C, vacuum drying for 12 hours, then 140 ° C, vacuum drying 12 hours; DMDBS, antioxidant, talcum powder drying process, 100 ℃, blast drying for 2 hours. After weighing the dried raw materials according to a certain ratio (as shown in Table 1), they were mixed evenly in a high-speed mixer. Put the mixed material into the rotating co-rotating twin-screw extruder (the diameter of the twin-screw is 45mm, and the ratio of length to diameter is 40), and a certain proportion of carbon dioxide is pumped into the extruder through the metering pumping system. polymer melt. Under the rotation of the screw, the injected carbon dioxide and PET resin melt form a homogeneous solution, which is transported to the outlet of the machine head. A melt pump is connected in series at the outlet of the twin-screw extruder. There is a sheet die at the outlet of the melt pump, and the sheet die The size is 200X0.6mm. Control the temperature at the single-screw extruder and the head, so that the melt temperature at the head is 250°C, and the pressure at the head is 5MPa. The process parameters of each section of the extruder are shown in Table 2. A PET foam sheet was obtained.

Performance characterization: use an analytical balance to test the apparent density of the foamed product according to the standard GB1033-86. Use ULTRAFOAM 1000 (U.S. Quantachrome Instruments company) to measure the closed cell ratio of foamed samples. The cell structure mainly refers to the cell size and cell density. The specific test method is: immerse the sample in liquid nitrogen, then take out the brittle fracture, make a sample, spray gold on the fracture surface, and observe the fracture morphology with SEM. Using the graphic analysis software Image-pro to process the scanning electron microscope photos, the number of cells counted is more than 100. The cell size is the average diameter of the cells of the foamed sample, which is directly calculated by the software; the cell density is the number of cells per cubic centimeter of the unfoamed sample.

The tensile property of PET foam sheet is tested according to GB/T9641-1988, the compressive strength is tested according to GB/T8813-2008, and the impact strength is tested according to GB/T 1043.1-2008

The test results are shown in Table 1.

Example 2-3

Using the same foaming process as in Example 1, the difference is that the content of each component in the raw material is different, and the melt temperature in the foaming process is different. In Example 3-4, the chain extender pyromellitic dianhydride (PMDA), analytically pure, produced by Sinopharm Chemical Reagent Company, was added.

Example 4

Polyethylene terephthalate, intrinsic viscosity 1.0dl/g (according to GB/T 14190-2008) test, solvent is phenol/1,1,2,2,-tetrachloroethane (mass ratio 50/50 ), Sinopec Yizheng Chemical Fiber Co., Ltd.;

Dibenzylsorbitol, Millad NX8001, thermal decomposition temperature 300°C, American Millken Company

Antioxidant Irganox1010, Germany BASF company.

Talc powder, 1000 mesh, Beijing Liguoweiye Powder Material Co., Ltd.

Azodicarbonamide, chemically pure, commercially available

Pre-dry polyethylene terephthalate (PET), dibenzyl sorbitol Millad NX8001, antioxidant, talcum powder, chemical foaming agent, etc. The drying process is: PET, 100 ° C, vacuum drying for 12 hours , and then 140 ° C, vacuum drying for 12 hours; Millad NX8001, antioxidant, talcum powder drying process, 100 ° C, blast drying for 2 hours. After weighing the dried raw materials according to a certain ratio (as shown in Table 1), they were mixed evenly in a high-speed mixer. Add the mixed material into the rotating single-screw extruder (single-screw diameter is 65mm, length-to-diameter ratio is 40), polymer melts under screw rotation, chemical blowing agent decomposes and releases volatile gas, and Mix evenly with the polymer melt, gradually lower the temperature of each zone near the outlet of the die, so that the melt temperature at the die outlet is transported to the outlet of the die at 245 ° C, the die outlet is a sheet die, and the sheet Die size is 200X0.6mm. The process parameters of each section of the extruder are shown in Table 2 to obtain a PET foam sheet.

The performance of the obtained PET foam sheet was tested by the same test method as in the examples, and the results are shown in Table 1.

Example 5

The same material as in Example 1, the difference is that the contents of each component are different, as shown in Table 1; the foaming process is different, and it is injection foaming, as follows:

Pre-dry polyethylene terephthalate (PET), DMDBS, antioxidant, talcum powder, etc., the drying process is: PET, 100 ° C, vacuum drying for 12 hours, then 140 ° C, vacuum drying for 12 hours; DMDBS ,Antioxidant, talcum powder drying process, 100 ℃, blast drying for 2 hours. After weighing the dried raw materials according to a certain ratio (as shown in Table 1), they were mixed evenly in a high-speed mixer. Put the mixed material into the rotating injection molding machine (the screw diameter of the injection molding machine is 25mm, and the aspect ratio is 30), and a certain proportion of nitrogen is pumped into the polymer melt in the extruder through the metering pumping system. Under the rotation of the screw, the injected nitrogen and PET resin melt form a homogeneous solution. The back pressure of the injection molding machine is controlled to 18MPa, and the melt temperature in the injection molding machine is 260°C. The process parameters of each section of the injection molding machine are shown in Table 3. The mixed plastic The melted PET melt containing foaming agent is injected into a flat mold to obtain a PET microcellular foaming material. The performance test results of the obtained PET microcellular foamed material are shown in Table 4.

Example 6

The materials and process are the same as in Example 5, except that the contents of each component are different, as shown in Table 3 for details. The obtained microcellular foamed material is subjected to a performance test, and the test results are shown in Table 4.

Example 7

The same material as in Example 4, except that the content of each component is different, as shown in Table 3 for details. The foaming process is chemical foaming agent injection foaming, as follows:

Pre-dry polyethylene terephthalate (PET), dibenzyl sorbitol, Millad NX8001, antioxidant, talcum powder, chemical foaming agent, etc. The drying process is: PET, 100 ° C, vacuum drying for 12 Hours, then 140 ° C, vacuum drying for 12 hours; DMDBS, antioxidant, talcum powder drying process, 100 ° C, blast drying for 2 hours. After weighing the dried raw materials according to a certain ratio (as shown in Table 1), they were mixed evenly in a high-speed mixer. Put the mixed material into the rotating injection molding machine (the screw diameter of the injection molding machine is 25mm, and the aspect ratio is 30). Under the rotation of the screw, the chemical blowing agent decomposes and releases volatile gas, which forms with the PET resin melt. Homogeneous solution, control the back pressure of the injection molding machine to 18MPa, and the melt temperature in the injection molding machine to 275°C. The process parameters of each section of the injection molding machine are shown in Table 3. Inject the mixed and plasticized PET melt containing foaming agent into the plate In the mold, a PET microcellular foamed product was obtained, and the performance test results of the obtained PET microcellular foamed material are shown in Table 4.

Example 8

The same material and process as in Example 7, except that the content of each component is different, and the foaming process parameters are different, as shown in Table 3, and the performance test results of the PET microcellular foamed material are shown in Table 4.

Comparative example 1

The same foaming process as in Example 1, the difference is that the composition of the aromatic polyester composition is different, no sorbitol compound is added in this comparative example, the content of each component and the process conditions are shown in Table 1, and the PET foam is obtained. The properties of the foam materials are shown in Table 2.

Comparative example 2

The same foaming process as in Example 4, the difference is that the composition of the aromatic polyester composition is different, no sorbitol compound is added in this comparative example, the specific content of each component and the process conditions are shown in Table 1, and PET The properties of the foamed materials are shown in Table 2.

Comparative example 3

The same foaming process as in Example 5, the difference is that the composition of the aromatic polyester composition is different, no sorbitol compound is added in this comparative example, the specific content of each component and the process conditions are shown in Table 3, and PET The properties of the foamed materials are shown in Table 4.

Comparative example 4

The same foaming process as in Example 7, except that the composition of the aromatic polyester composition is different, and no sorbitol compound is added in this comparative example. The specific content of each component and the process conditions are shown in Table 3, and the PET foam is obtained. The properties of the foam materials are shown in Table 4.

Table 1

Table 2

table 3

Table 4

While the foregoing description and drawings represent exemplary embodiments of the present invention, it should be understood that various additions, modifications and replace. Specifically, it should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, dimensions, and other elements, materials and components without departing from its spirit or essential characteristics. In addition, many variations of the methods/processes described herein may be made within the scope of the teachings herein. Those skilled in the art will further appreciate that this embodiment may be used with many modifications in structure, arrangement, proportions, dimensions, materials and components, or, in the practice of the present invention, to be particularly adapted to specific circumstances and operational requirements, without departing from the principles described herein. Accordingly, the embodiments of the present invention should be considered in all respects as illustrative and not restrictive. The appended claims are to be interpreted broadly to cover various modifications and embodiments of the present invention that may be made by those skilled in the art without departing from the scope and field of equivalent features.

Claims (10)

1. an aromatic polyester microcellular foaming material, prepared by an aromatic polyester composition through a foaming process, is characterized in that: the aromatic polyester composition comprises 100 parts by weight of aromatic polyester, sorbitol 0.5-5 parts by weight of benzylidene derivatives, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, and 0-2 parts by weight of cell nucleating agent; the aromatic polyester microcellular foaming material The apparent density is 0.05-1.10g/cm ³ , and the closed cell rate is not less than 80%. 2. The aromatic polyester microporous foam material according to claim 1, characterized in that: the aromatic polyester is polyethylene terephthalate. 3. The aromatic polyester microcellular foaming material according to any one of claims 1 to 2, characterized in that: the thermal decomposition temperature of the sorbitol benzylidene derivative is not lower than 300°C, preferably not lower at 320°C. 4. aromatic polyester microcellular foaming material according to claim 1, is characterized in that, described sorbitol benzylidene derivative is 2,4-O-(3,4-dimethylbenzylidene) - D-sorbitol (DMDBS). 5 . The aromatic polyester microporous foam material according to claim 1 , wherein the added amount of the sorbitol benzylidene derivative is 1-3% of the total weight of the aromatic polyester. 6. A preparation method of aromatic polyester microcellular foaming material, comprising: (1) 100 parts by weight of aromatic polyester, 0.5-5 parts by weight of sorbitol benzylidene derivatives, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent Parts by weight, mixed in proportion to form an aromatic polyester composition and then added to the extruder; (2) Injecting a physical foaming agent into the extruder, the injection amount of the physical foaming agent is 0.1-10% of the total weight of the aromatic polyester composition, and mixing in the extruder uniform; (3) Cool the melt of the aromatic polyester composition containing the physical blowing agent to 220-250°C, the die pressure is greater than 3MPa, and the aromatic polyester microcellular foam is obtained by foaming and shaping through the die Material. 7. A preparation method of aromatic polyester microcellular foaming material, comprising (1) 100 parts by weight of aromatic polyester, 0.5-5 parts by weight of sorbitol benzylidene derivatives, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent Parts by weight, 0.1-5 parts by weight of chemical foaming agent, mixed in proportion and added to the extruder, melted under the action of heating and screw shear plasticization, the chemical foaming agent decomposes to release volatile gas, in Mix uniformly in the extruder; (2) The aromatic polyester melt mixture containing the chemical foaming agent is extruded through a die and cooled and shaped to obtain an aromatic polyester microcellular foaming material. 8. A method for preparing an aromatic polyester microcellular foaming material, comprising: (1) 100 parts by weight of aromatic polyester, 0.5-5 parts by weight of sorbitol benzylidene derivatives, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent Parts by weight, mixed in proportion and then added to the injection molding machine, melted under the action of heating and screw shear plasticization; (2) sending a physical foaming agent into the aromatic polyester polymer melt in the injection molding machine, the amount of the physical foaming agent added is 0.1-1% of the total weight of the aromatic polyester composition, Mix evenly in the injection molding machine; (3) The aromatic polyester melt mixture containing the physical foaming agent is injected into a mold through an injection nozzle, cooled and shaped to obtain an aromatic polyester microcellular foamed material. 9. A method for preparing an aromatic polyester microcellular foaming material, comprising: (1) 100 parts by weight of aromatic polyester, 0.5-5 parts by weight of sorbitol benzylidene derivatives, 0.1-0.3 parts by weight of antioxidant, 0-2 parts by weight of chain extender, 0-2 parts by weight of cell nucleating agent Parts by weight, 0.1-1 parts by weight of chemical foaming agent are mixed in proportion, then added to the injection molding machine, and melted under the action of heating and screw shear plasticization; (2) injecting the aromatic polyester melt mixture containing the chemical foaming agent into a mold through an injection nozzle, cooling and shaping to obtain an aromatic polyester microcellular foaming material. 10. The preparation method of the aromatic polyester microcellular foaming material according to any one of claims 6 to 9, characterized in that: the added amount of the sorbitol benzylidene derivative is the total amount of the aromatic polyester 1-3% by weight.