Polyester foaming nucleating master batch and preparation method thereof, foaming material composition, foaming material and preparation method thereof

Abstract

The invention relates to the field of preparation of polyester foam materials, and discloses a polyester foam nucleating master batch and a preparation method thereof, a foam material composition, a foam material and a preparation method thereof, and the method comprises the following steps: mixing a monomer a, a monomer b and a catalyst, and carrying out esterification reaction to obtain an esterification product; adding an optional first nucleating agent into the esterification product to carry out a pre-polycondensation reaction to obtain a pre-polycondensation product; adding an optional second nucleating agent into the pre-polycondensation product to carry out final polycondensation reaction to obtain a polyester / nucleating agent blended melt, and cooling and pelletizing the polyester / nucleating agent blended melt to obtain a polyester foaming nucleating master batch; wherein the nucleating agent at least comprises at least one of a first nucleating agent and a second nucleating agent; the monomer a is binary acid containing aromatic rings; and the monomer b is C2-C8 dihydric alcohol. The nucleating agent in the polyester foaming nucleating master batch is good in dispersity, and the prepared foaming material is fine and uniform in foam structure and has the characteristics of small foam pore diameter and high foam pore density.

Description

Technical Field

[0001] The invention relates to the field of polyester foam material preparation, and in particular to a polyester foaming nucleating masterbatch and a preparation method thereof, a foaming material composition, a foaming material and a preparation method thereof. Background Art

[0002] Polyethylene terephthalate (PET) foam is one of the most widely used structural foam materials. Compared with polyvinyl chloride (PVC) foam, it has better mechanical properties and more efficient production and preparation technology. Compared with polyimide (PI) foam and polyetherimide (PEI) foam, it has a wider range of application scenarios due to its better economic applicability.

[0003] At present, PET foam materials are usually prepared by physical extrusion foaming, in which the cell density of the foam material has a significant effect on the mechanical properties and resin absorption of the PET foam. The increase in cell density will improve the mechanical properties of products with the same density while reducing the resin absorption of the foam material. Therefore, how to further optimize the cell density of PET foam materials has become a core and key technical issue in research. In the preparation process of the foam material, due to the sudden decrease in system pressure or the sudden increase in system temperature, the thermodynamic homogeneous equilibrium of the polymer melt / foaming agent is broken, resulting in an oversaturated state of the foaming agent, inducing the nucleation and growth process of the bubbles. Therefore, it can be said that the nucleation rate of the foaming process determines the cell density of the final foamed material.

[0004] The nucleation process can be divided into homogeneous nucleation and heterogeneous nucleation. Homogeneous nucleation is the nucleation process between the foaming agent gas and the polymer, while heterogeneous nucleation is the nucleation process between the foaming agent gas, the polymer, and the heterogeneous additive. Due to the introduction of heterogeneous additives, heterogeneous nucleation effectively reduces the nucleation energy barrier and greatly improves the nucleation rate. In actual production, heterogeneous nucleating agents are usually introduced to increase the nucleation rate of the foaming process. Therefore, homogeneous nucleation and heterogeneous nucleation exist simultaneously in the actual foaming process. Heterogeneous nucleating agents are mostly inorganic powders, including metal oxides and other natural mineral powders. However, when powders are used as heterogeneous nucleating agents and added to the extrusion foaming system, it is difficult for inorganic powders to produce a good mixing effect with plastic particles, and it is easy to produce stratification or agglomeration. Therefore, heterogeneous nucleating agents are often used as the main component, and are pre-melted and extruded with polymers to form nucleated foaming masterbatches containing heterogeneous nucleating agents, which are then used in the extrusion foaming process.

[0005] CN115772320A relates to a nucleating agent masterbatch, a foaming material and a preparation method thereof, and specifically discloses a nucleating agent masterbatch, a foaming material and a preparation method thereof. The components of the nucleating agent masterbatch are obtained by extrusion granulation, and are prone to the disadvantages of uneven dispersion, stratification or agglomeration.

[0006] CN113025007A relates to a polyester foam material and a preparation method thereof, and specifically discloses a polyester foam material and a preparation method thereof. The polyester and the nucleating agent are vacuum dried, and then mixed evenly with an antioxidant, a branching agent, and a chain extender; the raw materials are poured into an extruder, and the pressure and temperature of the extruded foam strips are rapidly reduced at the die to form pores. The nucleating agent of this method is also prone to the disadvantages of uneven dispersion, stratification or agglomeration during the extrusion foaming process.

[0007] Therefore, it is necessary to explore a new preparation method for polyester foaming nucleating masterbatch to achieve a fine and uniform pore structure of the foaming material. Summary of the invention

[0008] The purpose of the present invention is to overcome the problem in the prior art that heterogeneous nucleating agents are difficult to effectively disperse and mix, resulting in loose pore structures and poor uniformity of foamed materials. A polyester foaming nucleating masterbatch and a preparation method thereof, a foaming material composition, a foaming material and a preparation method thereof are provided. The nucleating agent in the polyester foaming nucleating masterbatch has good dispersibility, and the pore structure of the prepared foaming material is fine and uniform, and has the characteristics of small pore diameter and high pore density.

[0009] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a polyester foaming nucleating masterbatch, wherein the preparation method comprises:

[0010] (1) mixing monomer a, monomer b and a catalyst to carry out an esterification reaction to obtain an esterification product;

[0011] (2) adding an optional first nucleating agent to the esterification product to carry out a pre-polycondensation reaction to obtain a pre-polycondensation product;

[0012] (3) adding an optional second nucleating agent to the pre-polycondensation product to carry out a final polycondensation reaction to obtain a polyester / nucleating agent blended melt, and cooling and pelletizing the polyester / nucleating agent blended melt to obtain a polyester foaming nucleating masterbatch;

[0013] Wherein, at least one of the first nucleating agent and the second nucleating agent is included;

[0014] The monomer a is a dibasic acid containing an aromatic ring;

[0015] The monomer b is a C2-C8 diol.

[0016] The second aspect of the present invention provides a polyester foaming nucleating masterbatch prepared by the above preparation method.

[0017] The third aspect of the present invention provides a foaming material composition, wherein the composition comprises the above-mentioned polyester foaming nucleating masterbatch and a polymer material.

[0018] A fourth aspect of the present invention provides a foaming material, wherein the foaming material is obtained by foaming the foaming material composition.

[0019] A fifth aspect of the present invention provides a method for preparing a foaming material, wherein the method comprises: mixing, extruding, foaming, cooling and homogenizing the above-mentioned foaming material composition to obtain the foaming material.

[0020] Through the above technical scheme, the polyester foaming nucleating masterbatch and its preparation method, the foaming material composition, the foaming material and its preparation method provided by the present invention have the following beneficial effects.

[0021] The nucleating agent in the polyester foaming nucleating masterbatch of the invention has good dispersibility, the prepared foaming material has a fine and uniform pore structure, and the foaming material has the characteristics of small pore diameter and high pore density.

[0022] The present invention adds a nucleating agent in the polyester prepolymerization stage and / or the final polycondensation stage, and uses the stirring flow field in the polymerization reactor and the esterification product or precondensation product with low melt viscosity to efficiently disperse the nucleating agent in the polyester melt, so that the obtained foaming material has a fine and uniform pore structure. The phenomenon that the nucleating agent particles are easily agglomerated and accumulated in the polymer matrix during the melt extrusion blending process is avoided, resulting in a loose pore structure and poor uniformity of the foaming material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a scanning electron microscope image of the foamed material obtained in Test Example 1.

[0024] Figure 2 3 is a scanning electron microscope image of the foamed material obtained in comparative test example 1. DETAILED DESCRIPTION

[0025] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0026] The first aspect of the present invention provides a method for preparing a polyester foaming nucleating masterbatch, wherein the preparation method comprises:

[0027] (1) mixing monomer a, monomer b and a catalyst to carry out an esterification reaction to obtain an esterification product;

[0028] (2) adding an optional first nucleating agent to the esterification product to carry out a pre-polycondensation reaction to obtain a pre-polycondensation product;

[0029] (3) adding an optional second nucleating agent to the pre-polycondensation product to carry out a final polycondensation reaction to obtain a polyester / nucleating agent blended melt, and cooling and pelletizing the polyester / nucleating agent blended melt to obtain a polyester foaming nucleating masterbatch;

[0030] Wherein, at least one of the first nucleating agent and the second nucleating agent is included;

[0031] The monomer a is a dibasic acid containing an aromatic ring;

[0032] The monomer b is a C2-C8 diol.

[0033] In the present invention, by adding a nucleating agent in the polyester prepolymerization stage and / or the final polycondensation stage, the nucleating agent is efficiently dispersed in the polyester melt by means of the stirring flow field in the polymerization reactor and the esterification product or precondensation product with a lower melt viscosity, and the obtained foam material has a fine and uniform pore structure. The phenomenon that the nucleating agent particles are easily agglomerated and accumulated in the polymer matrix during the melt extrusion blending process is avoided, resulting in a loose pore structure and poor uniformity of the foam material.

[0034] Furthermore, the monomer a is selected from terephthalic acid and / or isophthalic acid.

[0035] Furthermore, the monomer b is selected from at least one of ethylene glycol, cyclohexanedimethanol and butanediol.

[0036] According to the present invention, the molar ratio of the monomer a to the monomer b is 1:1.7-2.4. Further, the molar ratio of the monomer a to the monomer b is 1:1.9-2.1.

[0037] According to the present invention, the catalyst is selected from at least one of antimony glycolate, antimony trioxide, antimony acetate and titanium glycolate.

[0038] Furthermore, the catalyst is antimony glycol and / or antimony acetate.

[0039] According to the present invention, based on the mass of monomer a, the amount of the catalyst used is 0.01 wt%-0.06 wt%.

[0040] Furthermore, based on the mass of monomer a, the amount of the catalyst used is 0.02wt%-0.05wt%.

[0041] According to the present invention, in step (1), the temperature of the esterification reaction is 200-270°C.

[0042] Furthermore, the temperature of the esterification reaction is 250-270°C.

[0043] In the present invention, there is no particular limitation on the time of the esterification reaction, and the esterification reaction can be stopped after the water generated during the esterification reaction is removed. The present invention does not particularly limit the method of removing water, for example, water can be removed by installing a steam trap on the reactor.

[0044] According to the present invention, the esterification reaction is carried out in the presence of a protective gas.

[0045] According to the present invention, the protective gas is selected from at least one of nitrogen, argon and helium.

[0046] According to the present invention, the pressure of the protective gas is 0.1-0.3 MPa.

[0047] According to the present invention, in step (2), the first nucleating agent and the second nucleating agent are each independently an inorganic nucleating agent.

[0048] Furthermore, the first nucleating agent and the second nucleating agent are each independently selected from at least one of talc, silicon dioxide, magnesium oxide, calcium oxide, calcium carbonate, carbon black and carbon nanotubes.

[0049] In the present invention, when the above nucleating agent is used, it can provide heterogeneous nucleation sites, reduce the nucleation energy barrier, increase the heterogeneous nucleation rate, and make the pore morphology of the foaming material more delicate.

[0050] Furthermore, the first nucleating agent and the second nucleating agent are each independently talc and / or calcium carbonate.

[0051] According to the present invention, the average particle diameters of the first nucleating agent and the second nucleating agent are independently 2.7-19 μm.

[0052] In the present invention, when the average particle size of the nucleating agent meets the above range, the particle size is suitable for uniform dispersion in the system, and at the same time can bring a larger specific surface contact area, can provide more contact sites, and make the pore morphology of the foaming material more delicate.

[0053] Furthermore, the average particle size of the first nucleating agent and the second nucleating agent is independently 5-15 μm.

[0054] According to the present invention, based on the mass of the esterification product, the total amount of the first nucleating agent and the second nucleating agent is 5wt%-30wt%.

[0055] In the present invention, when the amount of the nucleating agent meets the above range, it can simultaneously ensure the efficient nucleation ability of the nucleating masterbatch and ensure that the esterification process is not affected by excessive addition of the nucleating agent, which is conducive to obtaining a foaming material with small pore size and high pore density.

[0056] Furthermore, based on the mass of the esterification product, the total amount of the first nucleating agent and the second nucleating agent is 8wt%-20wt%.

[0057] Furthermore, based on the mass of the esterification product, the total amount of the first nucleating agent and the second nucleating agent is 9wt%-11wt%.

[0058] According to the present invention, based on the total weight of the first nucleating agent and the second nucleating agent, the amount of the first nucleating agent is 0-100 wt %.

[0059] According to the present invention, based on the total weight of the first nucleating agent and the second nucleating agent, the amount of the first nucleating agent is 60-100 wt %.

[0060] According to a preferred embodiment of the present invention, based on the total weight of the first nucleating agent and the second nucleating agent, the amount of the first nucleating agent is 100 wt%.

[0061] The invention adds a nucleating agent in the polyester prepolymerization stage, so that the nucleating agent can be efficiently dispersed in the polyester melt, and the obtained foaming material has a fine and uniform pore structure, a smaller pore diameter, and a higher pore density.

[0062] According to the present invention, in step (2), the temperature of the pre-polycondensation reaction is 220-280° C., and the time of the pre-polycondensation reaction is 20-60 min.

[0063] Furthermore, in step (2), the temperature of the pre-polycondensation reaction is 250-280° C., and the time of the pre-polycondensation reaction is 40-55 min.

[0064] According to the present invention, the vacuum degree of the pre-polycondensation reaction is ≤1500Pa.

[0065] Furthermore, the vacuum degree of the pre-polycondensation reaction is ≤1200Pa.

[0066] According to the present invention, in step (3), the temperature of the final polycondensation reaction is 250-280° C., and the time of the final polycondensation reaction is 40-120 min.

[0067] Furthermore, the temperature of the final polycondensation reaction is 265-275° C., and the time of the final polycondensation reaction is 50-90 min.

[0068] According to the present invention, the vacuum degree of the final polycondensation reaction is ≤200Pa.

[0069] Furthermore, the vacuum degree of the final polycondensation reaction is ≤100Pa.

[0070] The second aspect of the present invention provides a polyester foaming nucleating masterbatch prepared by the above preparation method.

[0071] In the present invention, the nucleating agent in the polyester foaming nucleating masterbatch has good dispersibility, the prepared foaming material has a fine and uniform pore structure, and the foaming material has the characteristics of small pore diameter and high pore density.

[0072] According to the present invention, based on the total mass of the polyester foaming nucleating masterbatch, the content of the nucleating agent is 5-30wt%, and the content of the polyester is 70-95wt%.

[0073] In the present invention, when the content of the components in the polyester foaming nucleating masterbatch meets the above range, the efficient nucleating ability of the nucleating masterbatch can be ensured at the same time, which is conducive to obtaining a foaming material with small pore size and high pore density.

[0074] Furthermore, based on the total mass of the polyester foaming nucleating masterbatch, the content of the nucleating agent is 9-11wt%, and the content of the polyester is 89-91wt%.

[0075] According to the present invention, the average particle size of the polyester foaming core masterbatch is 2-6 mm.

[0076] In the present invention, when the average particle size of the polyester foaming nucleating masterbatch meets the above range, it is beneficial for the nucleating masterbatch to be uniformly dispersed in the foaming material composition, and at the same time can bring a larger specific surface contact area and provide more contact sites, which is beneficial for obtaining a foaming material with a small pore size and a high pore density.

[0077] Furthermore, the average particle size of the polyester foaming core masterbatch is 3-4 mm.

[0078] According to the present invention, the intrinsic viscosity of the polyester foaming core masterbatch is 0.7-0.9 dL / g.

[0079] According to the present invention, the polyester in the polyester foaming nucleating masterbatch has a terminal carboxyl content of 20-30 mol / t.

[0080] In the present invention, when the characteristic viscosity and / or terminal carboxyl content of the polyester foaming nucleating masterbatch meets the above range, it is beneficial to avoid the molecular chain breakage caused by the subsequent extrusion and foaming process, thereby ensuring that the polyester matrix in the polyester foaming nucleating masterbatch can maintain good processing performance during the extrusion foaming process, and is more conducive to obtaining a foaming material with a fine and uniform pore structure.

[0081] The third aspect of the present invention provides a foaming material composition, wherein the composition comprises the above-mentioned polyester foaming nucleating masterbatch and a polymer material.

[0082] According to the present invention, based on 100 parts by weight of the polymer material, the amount of the polyester foaming core masterbatch is 0.1-5 parts by weight.

[0083] Furthermore, based on 100 parts by weight of the polymer material, the amount of the polyester foaming core masterbatch is 0.5-1.5 parts by weight.

[0084] According to the present invention, the polymer material is polyester.

[0085] Furthermore, it is at least one selected from polyethylene terephthalate, polybutylene terephthalate and polyethylene terephthalate-1,4-cyclohexanedimethanol.

[0086] Furthermore, the polymer material is polyethylene terephthalate.

[0087] According to the present invention, the composition further comprises an antioxidant.

[0088] In the present invention, there is no particular limitation on the choice of antioxidant, which may be a conventional antioxidant in the art, such as antioxidant 1010.

[0089] According to the present invention, based on 100 parts by weight of the polymer material, the amount of the antioxidant is 0.1-1 part by weight.

[0090] Furthermore, based on 100 parts by weight of the polymer material, the amount of the antioxidant is 0.15-0.20 parts by weight.

[0091] According to the present invention, the composition further comprises a chain extender.

[0092] In the present invention, there is no particular limitation on the selection of the chain extender, which may be any conventional chain extender in the art; preferably, the chain extender is selected from at least one of pyromellitic dianhydride, bisoxazoline and triglycidyl isocyanurate, more preferably pyromellitic dianhydride.

[0093] According to the present invention, based on 100 parts by weight of the polymer material, the amount of the chain extender is 0.1-1 parts by weight.

[0094] Furthermore, based on 100 parts by weight of the polymer material, the amount of the chain extender is 0.4-0.5 parts by weight.

[0095] According to the present invention, the composition further comprises a foaming agent.

[0096] In the present invention, there is no particular limitation on the selection of the blowing agent, which may be any conventional blowing agent in the art, such as cyclopentane.

[0097] According to the present invention, based on 100 parts by weight of the polymer material, the amount of the foaming agent is 0.1-5 parts by weight.

[0098] Furthermore, based on 100 parts by weight of the polymer material, the amount of the foaming agent is 1-3 parts by weight.

[0099] A fourth aspect of the present invention provides a foaming material, wherein the foaming material is obtained by foaming the foaming material composition.

[0100] According to the present invention, the cell density of the foaming material is 3×10 4 cells / cm 3 Up to 8×10 4 cells / cm 3 .

[0101] Furthermore, the cell density of the foaming material is 4×10 4 cells / cm 3 Up to 8×10 4 cells / cm 3 .

[0102] According to the present invention, the average pore size of the foaming material is less than or equal to 300 μm.

[0103] Furthermore, the average pore size of the foaming material is less than or equal to 280 μm.

[0104] A fifth aspect of the present invention provides a method for preparing a foaming material, wherein the method comprises: mixing, extruding, foaming, cooling and homogenizing the above-mentioned foaming material composition to obtain the foaming material.

[0105] In the present invention, there is no particular limitation on the foaming agent used during foaming, and conventional foaming agents in the art, such as cyclopentane foaming agent, can be used.

[0106] The present invention will be described in detail below through examples.

[0107] In the following examples, the average particle diameters of the nucleating agent and the polyester foaming nucleating masterbatch were measured by a particle size analyzer.

[0108] The amount of nucleating agent and polyester in the polyester foaming nucleating masterbatch: according to the same monomer feeding amount as in the example, without adding a nucleating agent, the polyester is prepared and weighed to obtain the mass of the polyester; then the polyester foaming nucleating masterbatch is prepared according to the example, and weighed to obtain the mass of the nucleating masterbatch; the content of the nucleating agent is calculated according to the formula.

[0109]

[0110] The intrinsic viscosity of the polyester foaming nucleating masterbatch was measured by an Ubbelohde viscometer and tested according to GB / T14190-2017.

[0111] The terminal carboxyl content of the polyester matrix in the polyester foaming core masterbatch is measured by titration analysis using a potassium hydroxide / ethanol mixed solution.

[0112] The cell density of the foamed material is measured by analyzing and calculating the scanning electron microscope image. Specifically, in the SEM image with a magnification of 50 times, the number of bubbles within the field of view is counted. The specific calculation formula is as follows:

[0113]

[0114] Where n is the number of bubbles, A is the image area, is the expansion ratio; the expansion ratio The density meter is used for testing and measurement. The principle is Archimedes drainage method and the test is based on ASTM D792-00 standard. Defined as the density of the sample before foaming ρ0 and the density of the sample after foaming ρ f The ratio is as shown in the following formula:

[0115]

[0116] The average pore size of the foamed material is measured by analyzing and calculating the scanning electron microscope image. Specifically, in a SEM image with a magnification of 50 times, the diameters of all bubbles in the image are counted and the average pore size of the foamed material is obtained by average calculation.

[0117] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the art.

[0118] Example 1

[0119] (1) Ethylene glycol (monomer b), terephthalic acid (monomer a) and ethylene glycol antimony catalyst are mixed and stirred to form a uniform system, wherein the molar ratio of monomer a to monomer b is 1:2, and the amount of the catalyst is 0.029wt% based on the mass of monomer a. The mixture is added into a polymerization kettle for esterification reaction, and the esterification reaction is carried out at 255° C. and protected by 0.2MPa N2 pressure until all the water generated by the reaction is effectively removed.

[0120] (2) Add 10% by mass of talcum powder (average particle size of 10 μm), continue to maintain the reaction temperature at 260° C., maintain the system vacuum at 1000 Pa, and carry out a pre-polycondensation reaction for 50 min.

[0121] (3) After the pre-polycondensation reaction is completed, a final polycondensation reaction is carried out at 270° C. and a vacuum degree of 50 Pa is maintained. The final polycondensation reaction time is 70 min to obtain a polyester / nucleating agent blended melt. The melt is discharged and water-cooled and pelletized to obtain a polyester foaming nucleating masterbatch A1.

[0122] Example 2

[0123] (1) Ethylene glycol (monomer b), terephthalic acid (monomer a) and ethylene glycol antimony catalyst are mixed and stirred to form a uniform system, wherein the molar ratio of monomer a to monomer b is 1:2, and the amount of the catalyst is 0.029wt% based on the mass of monomer a. The mixture is added into a polymerization kettle for esterification reaction, and the esterification reaction is carried out at 255° C. and protected by 0.2MPa N2 pressure until all the water generated by the reaction is effectively removed.

[0124] (2) Add 10% by mass of talcum powder (average particle size of 6.5 μm), continue to maintain the reaction temperature at 260° C., maintain the system vacuum at 1000 Pa, and carry out a pre-polycondensation reaction for 50 min.

[0125] (3) After the pre-polycondensation reaction is completed, a final polycondensation reaction is carried out, and the vacuum degree is maintained at 50 Pa at 270° C. The final polycondensation reaction time is 70 min to obtain a polyester / nucleating agent blended melt. The melt is discharged and water-cooled and pelletized to obtain a polyester foaming nucleating masterbatch A2.

[0126] Embodiment 3-8

[0127] Polyester foaming nucleating masterbatch A3-A8 was prepared according to the method of Example 1. The differences in the preparation methods are shown in Table 1.

[0128] Table 1

[0129]

[0130] Comparative Example 1

[0131] (1) adding 85 parts by weight of PET bottle-grade chips having an intrinsic viscosity of 0.8 dL / g, 10 parts by weight of talc (average particle size of 10 μm), 1 part by weight of a phthalate coupling agent, 2 parts by weight of zinc stearate, and 2 parts by weight of PE wax into a high-speed mixer and mixing at 80° C. for 20 minutes to obtain a mixture;

[0132] (2) The mixture obtained in the above step is fed into a parallel co-rotating twin screw at a constant mass flow rate, and the zone temperature of the twin screw is set to 200°C, 270°C, 275°C, 280°C, 280°C, 280°C, 280°C, 280°C, 270°C, and the extrusion die temperature is set to 270°C. After the blend is extruded from the die, it is drawn and pelletized by air cooling to obtain polyester foaming nucleating masterbatch D1. Based on the total mass of the polyester foaming nucleating masterbatch, the content of the nucleating agent is 10wt%, the content of the polyester is 85wt%, and the content of the coupling agent, zinc stearate and PE wax is 5wt%.

[0133] Comparative Example 2

[0134] (1) 85 parts by weight of PET bottle-grade chips with an intrinsic viscosity of 0.8 dL / g, 10 parts by weight of talc (average particle size 4.5 μm), 1 part by weight of a phthalate coupling agent, 2 parts by weight of zinc stearate, and 2 parts by weight of PE wax were added to a high-speed mixer and mixed at 80° C. for 20 minutes to obtain a mixture.

[0135] (2) The mixture obtained in the above step is fed into a parallel co-rotating twin screw at a constant mass flow rate, and the zone temperature of the twin screw is set to 200°C, 270°C, 275°C, 280°C, 280°C, 280°C, 280°C, 280°C, 270°C, and the extrusion die temperature is set to 270°C. After the blend is extruded from the die, it is drawn and pelletized by air cooling to obtain polyester foaming nucleating masterbatch D2. Based on the total mass of the polyester foaming nucleating masterbatch, the content of the nucleating agent is 10wt%, the content of the polyester is 85wt%, and the content of the coupling agent, zinc stearate and PE wax is 5wt%.

[0136] Comparative Example 3

[0137] The polyester foaming nucleating masterbatch D3 was prepared according to the preparation method of Example 1, except that in step (1), a nucleating agent was added, that is, monomer a, monomer b, a catalyst and a nucleating agent were mixed, and an esterification reaction was carried out to obtain an esterification product.

[0138] Table 2

[0139]

[0140] Test Example 1

[0141] 100 parts by weight of PET bottle-grade chips, 1 part by weight of polyester foaming nucleating masterbatch A1, 0.45 parts by weight of chain extender (pyromellitic anhydride) and 0.125 parts by weight of antioxidant (antioxidant 1010) were added into a twin screw for extrusion modification. The twin screw temperature was set at 280°C, and cyclopentane foaming agent was injected into the tail of the twin screw. Based on 100 parts by weight of PET bottle-grade chips, 2 parts by weight of cyclopentane foaming agent were added, and then the melt / gas mixture was extruded and transported to a single screw extruder in series, and cooled and homogenized to obtain a foamed material. The foamed material was quenched and gold-sprayed on the surface to make a scanning electron microscope test sample. The test results are shown in Table 3.

[0142] Test Example 2-8

[0143] The foaming material was prepared according to the method of Test Example 1, except that the polyester foaming nucleating masterbatch A1 was replaced with the polyester foaming nucleating masterbatch A3-A8 in sequence. The test results are shown in Table 3.

[0144] Test Example 9

[0145] The foaming material was prepared according to the method of Test Example 1, except that 100 parts by weight of PET bottle-grade chips, 0.5 parts by weight of polyester foaming nucleating masterbatch A1, 0.45 parts by weight of chain extender (pyromellitic anhydride) and 0.125 parts by weight of antioxidant (antioxidant 1010) were added into the twin-screw for extrusion modification.

[0146] Test Example 10

[0147] The foaming material was prepared according to the method of Test Example 1, except that 100 parts by weight of PET bottle-grade chips, 5 parts by weight of polyester foaming nucleating masterbatch A1, 0.45 parts by weight of chain extender (pyromellitic anhydride) and 0.125 parts by weight of antioxidant (antioxidant 1010) were added into the twin-screw for extrusion modification.

[0148] Comparative test examples 1-3

[0149] The foaming material was prepared according to the method of Test Example 1, except that the polyester foaming nucleating masterbatch A1 was replaced by the polyester foaming nucleating masterbatch D1, the polyester foaming nucleating masterbatch D2, and the polyester foaming nucleating masterbatch D3 in sequence. The properties of the prepared foaming material are shown in Table 3.

[0150] Table 3

[0151] <![CDATA[Cell density cells / cm 3 > Average pore size / μm Test Example 1 <![CDATA[7.43×10 4 ]]> 201.6 Test Example 2 <![CDATA[5.12×10 4 ]]> 247.9 Test Example 3 <![CDATA[3.87×10 4 ]]> 276.1 Test Example 4 <![CDATA[3.42×10 4 ]]> 292.8 Test Example 5 <![CDATA[2.92×10 4 ]]> 317.6 Test Example 6 <![CDATA[4.93×10 4 ]]> 257.7 Test Example 7 <![CDATA[5.71×10 4 ]]> 223.8 Test Case 8 <![CDATA[5.23×10 4 ]]> 239.2 Test Example 9 <![CDATA[2.89×10 4 ]]> 321.9 Test Example 10 <![CDATA[3.03×10 4 ]]> 312.7 Comparative test example 1 <![CDATA[2.73×10 4 ]]> 324.1 Comparative test example 2 <![CDATA[0.81×10 4 ]]> 472.8 Comparative test example 3 <![CDATA[3.17×10 4 ]]> 300.1

[0152] It can be seen from the results in Table 3 that Example 1 of the present invention has a significantly better effect.

[0153] Figure 1 is a scanning electron microscope image of the foamed material obtained in Test Example 1. Figure 2 It is a scanning electron microscope image of the foamed material obtained in comparative test example 1. It can be seen from the attached figure that when polyester foaming nucleating masterbatch A1 is used as the nucleating agent in the PET extrusion foaming process, the foamed material has a more delicate and uniform pore structure; while when polyester foaming nucleating masterbatch D1 is used as the nucleating agent in the PET extrusion foaming process, the pore structure shows obvious uneven distribution and the pores are relatively sparse. This is because when the nucleating masterbatch is processed in a twin-screw, the talcum powder and the highly viscous PET melt cannot be truly evenly dispersed, and the interface between the talcum powder particles makes it difficult to be effectively stripped by the shear flow field of the screw. Even after adding a phthalate coupling agent and performing corresponding surface chemical treatment, the dispersion and mixing of the talcum powder particles cannot be achieved.

[0154] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing polyester foaming nucleating masterbatch, characterized in that: The preparation method comprises: (1) mixing monomer a, monomer b and a catalyst to carry out an esterification reaction to obtain an esterification product; (2) adding an optional first nucleating agent to the esterification product to carry out a pre-polycondensation reaction to obtain a pre-polycondensation product; (3) adding an optional second nucleating agent to the pre-polycondensation product to carry out a final polycondensation reaction to obtain a polyester / nucleating agent blended melt, and cooling and pelletizing the polyester / nucleating agent blended melt to obtain a polyester foaming nucleating masterbatch; Wherein, at least one of the first nucleating agent and the second nucleating agent is included; The monomer a is a dibasic acid containing an aromatic ring; The monomer b is a C2-C8 diol.

2. The preparation method according to claim 1, wherein In step (1), the monomer a is selected from terephthalic acid and / or isophthalic acid; Preferably, the monomer b is selected from at least one of ethylene glycol, cyclohexanedimethanol and butanediol; Preferably, the molar ratio of monomer a to monomer b is 1:1.7-2.4, preferably 1:1.9-2.1; Preferably, the catalyst is selected from at least one of antimony glycolate, antimony trioxide, antimony acetate and titanium glycolate, preferably antimony glycolate and / or antimony acetate; Preferably, based on the mass of monomer a, the amount of the catalyst used is 0.01 wt%-0.06 wt%, preferably 0.02 wt%-0.05 wt%.

3. The preparation method according to claim 1 or 2, wherein In step (1), the temperature of the esterification reaction is 200-270°C, preferably 250-270°C; Preferably, the esterification reaction is carried out in the presence of a protective gas; Preferably, the protective gas is selected from at least one of nitrogen, argon and helium; Preferably, the pressure of the protective gas is 0.1-0.3 MPa.

4. The preparation method according to any one of claims 1 to 3, wherein In step (2), the first nucleating agent and the second nucleating agent are each independently an inorganic nucleating agent; Preferably, the first nucleating agent and the second nucleating agent are each independently selected from at least one of talc, silicon dioxide, magnesium oxide, calcium oxide, calcium carbonate, carbon black and carbon nanotubes, preferably talc and / or calcium carbonate; Preferably, the average particle size of the first nucleating agent and the second nucleating agent is independently 2.7-19 μm, preferably 5-15 μm; Preferably, based on the mass of the esterification product, the total amount of the first nucleating agent and the second nucleating agent is 5wt%-30wt%, preferably 8wt%-20wt%, more preferably 9wt%-11wt%; Preferably, based on the total weight of the first nucleating agent and the second nucleating agent, the amount of the first nucleating agent is 0-100 wt%, preferably 60-100 wt%.

5. The preparation method according to any one of claims 1 to 4, wherein: In step (2), the temperature of the pre-polycondensation reaction is 220-280° C., preferably 250-280° C.; Preferably, the pre-polycondensation reaction time is 20-60 min, preferably 40-55 min; Preferably, the vacuum degree of the pre-polycondensation reaction is ≤1500Pa, preferably ≤1200Pa.

6. The preparation method according to any one of claims 1 to 5, wherein: In step (3), the temperature of the final polycondensation reaction is 250-280°C, preferably 265-275°C; Preferably, the final polycondensation reaction time is 40-120 min, preferably 50-90 min; Preferably, the vacuum degree of the final polycondensation reaction is ≤200Pa, preferably ≤100Pa.

7. A polyester foaming nucleating masterbatch prepared by the preparation method according to any one of claims 1 to 6; Preferably, based on the total mass of the polyester foaming nucleating masterbatch, the content of the nucleating agent is 5-30wt%, preferably 9-11wt%; the content of the polyester is 70-95wt%, preferably 89-91wt%; Preferably, the average particle size of the polyester foaming core masterbatch is 2-6 mm, preferably 3-4 mm; Preferably, the intrinsic viscosity of the polyester foaming core masterbatch is 0.7-0.9 dL / g; Preferably, the content of terminal carboxyl groups of the polyester in the polyester foaming core masterbatch is 20-30 mol / t.

8. A foaming material composition, characterized in that: The composition comprises the polyester foaming nucleating masterbatch according to claim 7 and a polymer material; Preferably, based on 100 parts by weight of the polymer material, the amount of the polyester foaming core masterbatch is 0.5-5 parts by weight, preferably 0.8-1.5 parts by weight; Preferably, the polymer material is polyester; Preferably, the polymer material is selected from at least one of polyethylene terephthalate, polybutylene terephthalate and polyethylene terephthalate-1,4-cyclohexanedimethanol, preferably polyethylene terephthalate.

9. The composition according to claim 8, wherein The composition also includes an antioxidant; Preferably, based on 100 parts by weight of the polymer material, the amount of the antioxidant is 0.1-1 parts by weight, preferably 0.15-0.2 parts by weight; Preferably, the composition further comprises a chain extender; Preferably, based on 100 parts by weight of the polymer material, the amount of the chain extender is 0.1-1 parts by weight, preferably 0.4-0.5 parts by weight; Preferably, the composition further comprises a foaming agent; Preferably, based on 100 parts by weight of the polymer material, the amount of the foaming agent is 0.1-5 parts by weight, preferably 1-3 parts by weight.

10. A foaming material, characterized in that: The foaming material is obtained by foaming the foaming material composition according to claim 8 or 9.

11. A method for preparing a foaming material, characterized in that: The method comprises: mixing, extruding, foaming, cooling and homogenizing the foaming material composition according to claim 8 or 9 to obtain a foaming material.

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