CN112011155A

CN112011155A - Thermoplastic copolyester elastomer/AS resin composite material foaming master batch and preparation method and application thereof

Info

Publication number: CN112011155A
Application number: CN202010732657.2A
Authority: CN
Inventors: 汪凯; 冉启迪; 李院院
Original assignee: Zhejiang Henglan Technology Co Ltd
Current assignee: Zhejiang Henglan Technology Co Ltd
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2020-12-01
Anticipated expiration: 2040-07-27
Also published as: CN112011155B

Abstract

The invention relates to the technical field of thermoplastic elastomer foaming, and aims at solving the problem of uneven dispersion of chain extenders and the like in the extrusion foaming process of thermoplastic elastomers, the invention provides a thermoplastic copolyester elastomer/AS resin composite material foaming master batch which comprises 24-100 parts of thermoplastic polyester elastomer, 1-50 parts of AS resin, 0-50 parts of nucleating agent, 0-30 parts of antioxidant, 1-50 parts of chain extender and 0.1-5 parts of lubricant. The invention takes the polymer thermoplastic copolyester elastomer as a carrier to prepare the chain extender into a master batch form, can improve the dispersibility of the chain extender, avoids the phenomenon of uneven dispersion easily caused by directly adding the powdery chain extender, and reduces the environmental pollution. The invention also provides a preparation method and application of the foaming master batch.

Description

Thermoplastic copolyester elastomer/AS resin composite material foaming master batch and preparation method and application thereof

Technical Field

The invention relates to the technical field of thermoplastic elastomer foaming, in particular to a thermoplastic copolyester elastomer/AS resin composite material foaming master batch and a preparation method and application thereof.

Background

The foam plastic is a composite material containing a large amount of bubbles in the matrix, has excellent properties of light weight, high strength, low heat conduction, low sound insulation, impact resistance and the like, can be used as an anti-freezing heat-insulating, buffering and silencing damping material, and is widely applied to buildings, transportation, packaging and daily necessities. Compared with the traditional foam plastic, the thermoplastic polyester has excellent heat resistance and mechanical property, good dimensional stability and excellent mechanical property under the condition of higher temperature, but the thermoplastic polyester has poor thermal stability, is easy to absorb water to generate thermal degradation and hydrolysis, has relatively reduced viscosity and melt strength, cannot fully retain foaming gas, and limits the application of the thermoplastic polyester in the foaming field. In order to overcome the disadvantages of thermoplastic polyesters, the prior art methods for increasing the melt strength of polyesters have been mainly to add branching agents to the polyester during polymerization to obtain branched polyesters or to add chain extenders to the polyester during extrusion to increase the molecular weight of thermoplastic polyesters, such branching agents or chain extenders mainly comprising tricarboxylic acids, tetracarboxylic acids or polyols.

Chinese patent CN106928663A discloses a continuous extrusion preparation method of PET with high foaming ratio, which is characterized in that premix of chain extender, antioxidant and nucleating agent and foaming agent are added in the process of double-screw extrusion of PET, the strength of PET melt is improved, and gas is fully reserved, so that the foam cell structure of PET sheet with high foaming ratio is obtained. However, the PET sheet prepared by the method has insufficient toughness, and the application of the PET foaming material in the fields of packaging and the like is limited. And the chain extender, the antioxidant, the nucleating agent and the like are all powder, so that the problem of stacking is easy to occur when the polyester foaming body is prepared by twin-screw continuous extrusion, and the chain extender, the nucleating agent and the like are distributed unevenly, so that the problems of uneven foam holes, unstable foam hole structure, substandard mechanical property and the like of the foaming body are caused. There is a need to provide an ideal solution.

Chinese patent CN102056967A discloses a method for preparing a thermoplastic foam by adding a thermoplastic copolyester elastomer and a pre-mixture of chain extender to a polyester matrix, but the method does not relate to the concept of polyester/copolyester elastomer master batch, nor to elastomer/AS resin co-polymerization compounded toughened polyester foam.

Disclosure of Invention

The invention provides a thermoplastic copolyester elastomer/AS resin composite material foaming master batch and a preparation method thereof, aiming at overcoming the problem of uneven dispersion of a chain extender and the like in the extrusion foaming process of a thermoplastic elastomer. The master batch prepared by the invention has high compatibility with polyester, the foaming agent can be well dispersed and in a continuous phase, the obtained product has uniform and compact foam holes and lower opening rate, the polyester or polyester-based composite material product with low density and high toughness can be prepared, the production process is highly continuous and stable, the production process is safe and free of environmental pollution, and the method is suitable for industrial mass production.

In order to achieve the purpose, the invention adopts the following technical scheme:

a thermoplastic copolyester elastomer/AS resin composite material foaming master batch comprises the following components in parts by weight:

thermoplastic polyester elastomer: 24-100 parts of

AS resin: 1-50 parts

Nucleating agent: 0 to 50 portions of

Antioxidant: 0 to 30 portions of

Chain extender: 1-50 parts

Lubricant: 0.1-5 parts.

The invention takes the polymer thermoplastic copolyester elastomer as a carrier to prepare the chain extender into a master batch form, can improve the dispersibility of the chain extender, avoids the phenomenon of uneven dispersion easily caused by directly adding the powdery chain extender, and reduces the environmental pollution. The AS resin is acrylonitrile-styrene copolymer. Wherein too little thermoplastic copolyester elastomer and AS resin content will not completely cover the chain extender, nucleating agent or antioxidant, resulting in uneven dispersion. The chain extender can increase the strength and viscosity of the melt, retain more gas in the foaming process and prevent the reduction of mechanical properties caused by cell breakage. The nucleating agent can increase the cell density and reduce the cell diameter. The lubricant is mainly used for reducing the shearing friction force between each component and a screw and equipment, increasing the fluidity of a matrix, reducing the friction heat generated in the processing process and simultaneously improving the dispersibility of the powder reagent in the matrix; too little lubricant is not beneficial to polymer plasticization; excessive lubricant easily causes the material and the screw to slip, and causes the phenomena of uneven plasticization and uneven material mixing.

Preferably, the thermoplastic copolyester elastomer is TPEE and/or TPES/TPET. TPEE is a linear block copolymer containing polyester hard segments and aliphatic polyester or polyether soft segments, has excellent elasticity of rubber and easy processability of thermoplastic plastics, and has adjustable hardness. The rigidity, polarity and crystallinity of the TPEE hard segment ensure that the TPEE has outstanding strength and better high temperature resistance, creep resistance, solvent resistance and impact resistance, and the low glass transition temperature and the saturability of the soft segment polyether ensure that the TPEE has excellent low temperature resistance and aging resistance. TPES/TPET is a compound material with the advantages of small density, high toughness and good dimensional stability of the foaming polyester. Wherein TPES is a thermoplastic copolyester elastomer containing soft polyester segments, and TPET is a thermoplastic copolyester elastomer containing soft polyether segments.

Preferably, the chain extender is one or a mixture of more of pyromellitic dianhydride, trimethylolpropane and biphenyl tetracarboxylic dianhydride.

Preferably, the nucleating agent is one or a mixture of more of superfine talcum powder, active nano-zinc oxide and nano-silicon dioxide. The nonpolar part of the nano nucleating agent forms dents on the surface to contain molecular chains of the polyester and arrange the molecular chains in order, and the spherulites of the polyester collide with other spherulites without growing up, so that the size of the spherulites of the polyester is greatly reduced. The surfaces of the 3 nucleating agents all have active silicon hydroxyl, when the foaming master batch and the polyester are extruded to prepare the polyester foaming body, the hydroxyl can react with carboxyl of the polyester, so that the linear polyester is long-chain branched, compared with a linear chain with the same mass fraction, the relaxation time of the long-chain branched chain is longer, and the long-chain branched chain can be completely relaxed at a lower forming speed, namely, the long-chain branched polyester begins to shear and thin at a lower deformation speed, therefore, a proper amount of long-chain branched chain can improve the processing performance of the polyester, improve the melt strength of the polyester, resist the growth and deformation of cells, and obtain an ideal cell structure.

Preferably, the antioxidant is antioxidant 1010 and/or antioxidant 168.

Preferably, the lubricant is one or a mixture of more of CBT-100 resin, hyperbranched polyester, white oil or polyethylene wax.

The invention also provides a preparation method of the thermoplastic copolyester elastomer/AS resin composite material foaming master batch, which comprises the following steps:

(1) uniformly mixing the metered thermoplastic copolyester elastomer, the chain extender and half of the metered lubricant in a high-speed mixer, and then extruding and granulating by adopting a double screw, wherein the temperature of a cylinder body is 140-220 ℃, and the rotating speed of the screw is 50-300 r/min;

(2) uniformly mixing the weighed AS resin, nucleating agent, antioxidant and half of the weighed lubricant in a high-speed mixer, and then extruding and granulating by adopting a double screw, wherein the temperature of a cylinder is 190 ℃ and 270 ℃, and the rotating speed of the screw is 50-300 r/min; extruding and granulating by a double screw;

(3) granulating the two granules obtained in the steps (1) and (2) in a double-screw extruder unit to obtain the foaming master batch, wherein the temperature of a cylinder body is 180-.

The double-screw extrusion granulation in the step (1) can improve the dispersibility of the chain extender in the polymer carrier, and the double-screw extrusion granulation in the step (2) can improve the dispersibility of the nucleating agent and the antioxidant in the AS resin. Through the preparation steps, the problem of dispersion of the powdery chain extender, the antioxidant and the nucleating agent in the matrix is solved, the chain extender is prevented from reacting in the processing process, and the quality of the foaming master batch is ensured.

The invention also provides an application of the thermoplastic copolyester elastomer/AS resin composite material foaming master batch, wherein the foaming master batch and the polyester are fed into a double screw according to the mass ratio of (3-5) to (17), carbon dioxide with the mass of 0.1-0.8% of that of the polyester is injected into the middle section of a double screw extruder, and the polyester foaming body is prepared by extrusion foaming. Compared with polyolefin carriers, the thermoplastic copolyester elastomer such as TPEE and TPES/TPET has good compatibility with polyester, is not easy to generate phase separation phenomenon in the extrusion processing process, can provide certain toughness for foam pores, and is beneficial to foaming. The foaming agent can be well dispersed in a continuous phase, the obtained product has uniform and compact foam pores and lower opening rate, and can be added into a polyester material to prepare a polyester or polyester-based composite material product with low density and high toughness through twin-screw extrusion foaming or intermittent foaming molding.

Preferably, the polyester is polyethylene terephthalate PET or polybutylene terephthalate PBT.

Preferably, the polyester is polymerized from ethylene glycol and an acid, and the AS resin is a high temperature grade.

Therefore, the invention has the following beneficial effects: the foaming master batch with the TPEE/AS or TPES/TPET/AS AS the carrier can be used in foaming application of polyester materials and composite materials thereof, has low requirement on equipment, simple preparation process and high production efficiency, and can better improve the dispersibility of a chain extender, an antioxidant and a nucleating agent in a matrix, thereby ensuring the uniformity and stability of foam pores of a polyester foaming body and improving the mechanical property.

Drawings

FIGS. 1 to 4 are schematic views showing cell morphologies of the polyester foams obtained in examples 1 to 4, respectively.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples.

In the present invention, unless otherwise specified, all the raw materials and equipment used are commercially available or commonly used in the art, and the methods in the examples are conventional in the art unless otherwise specified.

Example 1

A preparation method of thermoplastic copolyester elastomer/AS resin composite material foaming master batch comprises the following steps:

(1) uniformly mixing 24.75 parts of TPEE, 0.25 part of CBT-100 resin and 25 parts of pyromellitic dianhydride in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder body is 150 ℃, and the rotating speed of screws is 100 r/min;

(2) uniformly mixing 24.75 parts of high-temperature-resistant AS resin, 12.5 parts of nano silicon dioxide, 12.5 parts of antioxidant 1010 and 0.25 part of CBT-100 resin in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder is 250 ℃, and the rotating speed of screws is 100 r/min;

(3) and (3) uniformly mixing the granules obtained in the steps (1) and (2), and then extruding and granulating by using a double-screw extruder to obtain foaming master batches, wherein the charging barrel temperature is 250 ℃, and the screw rotating speed is 150 r/min.

And (3) feeding the foaming master batch obtained in the step (3) and PET polyester into a double screw according to the mass ratio of 3:17, injecting carbon dioxide with the mass of 0.3% of that of the polyester into the middle section of a double screw extruder, and extruding and foaming to obtain the polyester foam. The cell morphology of the polyester foam is shown in FIG. 1.

Example 2

(1) uniformly mixing 29.75 parts of TPEE, 0.25 part of CBT-100 resin and 20 parts of pyromellitic dianhydride in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder body is 150 ℃, and the rotating speed of screws is 100 r/min;

(2) - (3) same as in example 1.

And (3) feeding the foaming master batch obtained in the step (3) and PET polyester into a double screw according to the mass ratio of 1:4, injecting carbon dioxide with the mass of 0.3% of that of the polyester into the middle section of a double screw extruder, and extruding and foaming to obtain the polyester foam. The cell morphology of the polyester foam is shown in FIG. 2.

Example 3

(1) uniformly mixing 34.75 parts of TPEE, 0.25 part of CBT-100 resin and 15 parts of pyromellitic dianhydride in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder body is 150 ℃, and the rotating speed of screws is 100 r/min;

(2) - (3) same as in example 1.

And (3) feeding the foaming master batch obtained in the step (3) and PET polyester into a double screw according to the mass ratio of 5:17, injecting carbon dioxide with the mass of 0.3% of that of the polyester into the middle section of a double screw extruder, and extruding and foaming to obtain the polyester foam. The cell morphology of the polyester foam is shown in FIG. 3.

Example 4

(1) uniformly mixing 39.75 parts of TPEE, 0.25 part of CBT-100 resin and 10 parts of pyromellitic dianhydride in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder body is 150 ℃, and the rotating speed of screws is 100 r/min;

(2) - (3) same as in example 1.

And (3) feeding the foaming master batch obtained in the step (3) and PET polyester into a double screw according to the mass ratio of 1:5, injecting carbon dioxide with the mass of 0.3% of that of the polyester into the middle section of a double screw extruder, and extruding and foaming to obtain the polyester foam. The cell morphology of the polyester foam is shown in FIG. 4.

Example 5

(1) uniformly mixing 24 parts of TPES/TPET, 0.05 part of white oil and 1 part of trimethylolpropane in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder body is 140 ℃, and the rotating speed of screws is 50 r/min;

(2) uniformly mixing 1 part of AS resin, 30 parts of antioxidant (10 parts of antioxidant 1010 and 20 parts of antioxidant 168) and 0.05 part of white oil in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder body is 190 ℃, and the rotating speed of screws is 50 r/min;

(3) and (3) uniformly mixing the granules obtained in the steps (1) and (2), and then extruding and granulating by using a double-screw extruder to obtain foaming master batches, wherein the temperature of a charging barrel is 180 ℃, and the rotating speed of a screw is 100 r/min.

And (3) feeding the foaming master batch obtained in the step (3) and PBT polyester into a double screw according to the mass ratio of 4:17, injecting carbon dioxide with the mass of 0.1% of that of the polyester into the middle section of a double screw extruder, and extruding and foaming to obtain the polyester foam.

Example 6

(1) uniformly mixing 100 parts of thermoplastic polyester elastomer (50 parts of TPES/TPET and 50 parts of TPEE), 2.5 parts of hyperbranched polyester and 50 parts of chain extender (20 parts of biphenyl tetracarboxylic dianhydride and 30 parts of trimethylolpropane) in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder body is 220 ℃, and the rotating speed of a screw is 300 r/min;

(2) uniformly mixing 50 parts of AS resin, 50 parts of nucleating agent (25 parts of superfine talcum powder and 25 parts of active nano zinc oxide) and 2.5 parts of hyperbranched polyester in a mixer, and then extruding and granulating by using a double-screw extruder, wherein the temperature of a cylinder is 270 ℃, and the rotating speed of a screw is 300 r/min;

(3) and (3) uniformly mixing the granules obtained in the steps (1) and (2), and then extruding and granulating by using a double-screw extruder to obtain foaming master batches, wherein the charging barrel temperature is 270 ℃, and the screw rotating speed is 120 r/min.

And (3) feeding the foaming master batch obtained in the step (3) and PBT polyester into a double screw according to the mass ratio of 1:3, injecting carbon dioxide with the mass of 0.8% of that of the polyester into the middle section of a double screw extruder, and extruding and foaming to obtain the polyester foam.

Comparative example 1

The only difference from example 1 is that the nucleating agent was replaced by nanosilica for potassium benzoate.

Comparative example 2

The PET polyester, the foaming agent, the pyromellitic dianhydride, the CBT-100 resin, the nano-silica and the antioxidant 1010 which are used in the same amount as the PET polyester in example 1 are uniformly mixed by adopting a one-step extrusion foaming method, and then extruded and foamed by adopting a double-screw extruder to prepare the polyester foam.

Comparative example 3

A two-step extrusion foaming method is adopted, PET polyester, pyromellitic dianhydride, CBT-100 resin and antioxidant 1010 with the same amount as that in example 1 are mixed, then chain extension reaction is carried out in a double-screw extrusion granulator to obtain high-viscosity polyester, and then a foaming agent and nano silicon dioxide are added to be extruded and foamed in a single-screw extruder to be molded.

Performance testing

The polyester foam obtained above was subjected to a test, and the results are shown in the following table.

	Cell size/. mu.m	Tensile strength/MPa	Percent elongation at shear%	Compressive strength/MPa
					Example 1	200	2.05	7.02	1.75
Example 2	150	2.59	9.19	2.01
					Example 3	100	3.0	12.09	3.08
Example 4	75	3.5	15.12	4.60
					Example 5	320	1.86	6.25	1.39
Example 6	74	4.48	16.83	5.36
					Comparative example 1	210	2.0	6.94	1.52
Comparative example 2	330	1.57	5.32	1.06
					Comparative example 3	200	1.82	6.18	1.37

As can be seen from the combination of FIGS. 1-4, when the foaming master batch of the present invention is used for preparing the polyester foam, the cell density is large and the distribution is uniform, and in the comparative examples 1-4, the impact strength of the foam is increased with the increase of the amount of TPEE. In example 5, no nucleating agent was used, so the pore size was large. Moreover, the mechanical properties are inferior because the thermoplastic copolyester elastomer and AS resin are too low in content and cannot completely cover the assistant, resulting in uneven dispersion. Of course, the amount of antioxidant added in practice is not generally as much as in example 5, which is mainly a matter of convenience. The only difference between comparative example 1 and example 1 is that the nucleating agent was replaced by nanosilica for potassium benzoate. Both potassium benzoate and nanosilica were alpha nucleating agents depending on the crystalline morphology, but comparative example 1 was less effective than example 1. The reason is presumed to be that the hydroxyl on the surface of the nano silicon dioxide reacts with the terminal carboxyl of the PET, so that the linear chain is branched, the processing performance of the PET is improved, the melt strength of the polyester is improved, the cell growth deformation is resisted, the cell size is uniform, and the strength of the polyester foam is increased. Comparative examples 2 and 3 adopt a one-step extrusion foaming method and a two-step extrusion foaming method in the existing PET extrusion foaming process route respectively: the PET melt strength modification and foaming of the one-step extrusion foaming method are carried out in the same extrusion process, namely PET, a foaming agent, a chain extender and other auxiliary agents are mixed uniformly and then directly extruded and foamed for molding; the melt strength modification and the foaming process are separated in the two-step extrusion foaming method, namely PET, a chain extender and other auxiliary agents are mixed and then subjected to chain extension reaction in a double-screw extrusion granulator to obtain high-viscosity polyester, and then a foaming agent and a nucleating agent are added to be extruded and foamed in a single-screw extruder. Compared with a one-step extrusion foaming method, the two-step extrusion foaming method has the advantages that the modification and foaming of PET are carried out separately, the PET is guaranteed to complete the chain extension reaction firstly, the PET can reach enough melt strength, and therefore the foaming material with a finer and more uniform cell structure is obtained. However, the two-step extrusion foaming method has the disadvantages that the high-viscosity polyester is easy to fluctuate when the double screw is metered, so that the chain extension is not uniform, and gel is generated. Although the cell size of comparative example 3 is similar to that of example 1, the uniformity of cell size of comparative example 3 is not as good as that of example 1, and the difference in mechanical properties can be confirmed. The invention utilizes the conventional polyester, the foaming master batch and the foaming agent to obtain the foaming polyester, the chain extender has high activity, and the uneven chain extension caused by high-viscosity polyester is overcome on the basis of having the advantages of a two-step extrusion foaming method.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The thermoplastic copolyester elastomer/AS resin composite material foaming master batch is characterized by comprising the following components in parts by weight:

thermoplastic polyester elastomer: 24-100 parts of

AS resin: 1-50 parts

Nucleating agent: 0 to 50 portions of

Antioxidant: 0 to 30 portions of

Chain extender: 1-50 parts

Lubricant: 0.1-5 parts.

2. The thermoplastic copolyester elastomer/AS resin composite foaming masterbatch according to claim 1, wherein the thermoplastic copolyester elastomer is TPEE and/or TPES/TPET.

3. The thermoplastic copolyester elastomer/AS resin composite foaming masterbatch of claim 1, wherein the chain extender is one or more of pyromellitic dianhydride, trimethylolpropane and biphenyl tetracarboxylic dianhydride.

4. The thermoplastic copolyester elastomer/AS resin composite foaming masterbatch of claim 1, wherein the nucleating agent is one or more of ultrafine talcum powder, active nano-zinc oxide and nano-silica.

5. The thermoplastic copolyester elastomer/AS resin composite foaming masterbatch according to claim 1, wherein the antioxidant is antioxidant 1010 and/or antioxidant 168.

6. The thermoplastic copolyester elastomer/AS resin composite foaming masterbatch of any one of claims 1-5, wherein the lubricant is one or more of CBT-100 resin, hyperbranched polyester, white oil or polyethylene wax.

7. The preparation method of the thermoplastic copolyester elastomer/AS resin composite foaming masterbatch according to any one of claims 1 to 6, characterized by comprising the following steps:

(2) uniformly mixing the weighed AS resin, nucleating agent, antioxidant and half of the weighed lubricant in a high-speed mixer, and then extruding and granulating by adopting a double screw, wherein the temperature of a cylinder is 190 ℃ and 270 ℃, and the rotating speed of the screw is 50-300 r/min;

8. The use of the thermoplastic copolyester elastomer/AS resin composite foaming masterbatch according to any one of claims 1 to 6, wherein the foaming masterbatch and the polyester are fed into a double screw according to the mass ratio (3-5) to 17, carbon dioxide with the mass of 0.1 to 0.8 percent of that of the polyester is injected into the middle section of a double screw extruder, and the polyester foam is obtained by extrusion and foaming.

9. The use of the thermoplastic copolyester elastomer/AS resin composite foaming masterbatch according to claim 8, wherein the polyester is polyethylene terephthalate (PET) or polybutylene terephthalate (PBT).

10. The use of the thermoplastic copolyester elastomer/AS resin composite foaming masterbatch of claim 8, wherein the polyester is polymerized from ethylene glycol and acid, and the AS resin is high temperature resistant.