Lightweight high-temperature-resistant high-resilience open-cell foam material and preparation method thereof

Abstract

The application provides a kind of lightweight high-temperature-resistant high-resilience open-cell foamed material and a preparation method thereof, and belongs to the technical field of high polymer foamed material.The lightweight high-temperature-resistant high-resilience open-cell foamed material is prepared by blending polypropylene, acicular wollastonite, dispersing agent, lubricant, coupling agent and antioxidant through a supercritical mould pressing foaming method.The micro-pore structure of the open-cell foamed material prepared by the application is an interconnected network structure, which solves the problem that the foaming pressure is high during the preparation of the current open-cell foamed material and industrial production is difficult;Meanwhile, the temperature resistance of the material is improved, it can be used under high temperature and high humidity conditions, has high resilience, can be reused, and is convenient for large-scale industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer foaming material preparation, and particularly relates to a light high-temperature-resistant high-resilience open-cell foaming material and a preparation method thereof. BACKGROUND

[0002] With the development of science and technology, people's demand for multifunctional materials is more and more wide, among which the demand for soft touch materials is mainly represented by foaming materials. The most commonly used foaming material is closed-cell material, but most application materials need high resilience and open-cell structure. There are not many domestic products of high-resilience open-cell foaming materials.

[0003] At present, the most commonly used high-resilience material is mainly elastomer, such as TPV, TPE, TPU and the like. These high-resilience materials can normally meet the use requirements in some occasions, but it is difficult to use them in occasions with relatively high temperature and humidity. If the resilience rate of the high-resilience material is further improved, the prepared high-resilience material will be softer and more temperature-resistant, and the cost will increase sharply. It is often difficult to pass the double-85 test, and it is also difficult to be applied in many occasions with high humidity and high temperature, and some functional aspects cannot be used, such as it is difficult to achieve water surface oil purification. Secondly, the commonly used high-resilience foaming material is sponge. Because the compression strength of the sponge is too low, it is difficult to meet the requirements of most application occasions. The sponge is formed by chemical polyurethane foaming, has a large odor and many harmful residues, which is not conducive to environmental protection. In addition, most sponges are semi-closed-cell structures, and it is difficult to achieve full open-cell structure, which has a great influence on the absorption efficiency.

[0004] Patent CN106084447B introduces a formula and method for preparing full open-cell material. The formula is in the form of multiphase blending. The full open-cell foaming material with interpenetrating network structure is prepared by supercritical molding foaming of polypropylene and thermoplastic elastomer. The prepared material is residue-free and environmentally friendly. However, this method requires a relatively large foaming pressure during production, generally higher than 25Mpa. It is difficult to meet the safety requirements of industrial production, and the large-scale production equipment cannot reach this pressure in a high-temperature environment. The disadvantages are obvious.

[0005] Therefore, it is necessary to find a light high-temperature-resistant high-resilience open-cell foaming material and a preparation method thereof to solve the problem that the current preparation of full open-cell foaming material is difficult to be industrialized due to the too large foaming pressure during production. SUMMARY

[0006] The present application aims to provide a light high-temperature-resistant high-resilience open-cell foaming material and a preparation method thereof to solve the problem that the current preparation of full open-cell foaming material is difficult to be industrialized due to the too large foaming pressure during production.

[0007] To achieve the above object, the present application provides the following technical solutions.

[0008] A light high-temperature-resistant high-rebound perforated foaming material, comprising the following components: 78-93 parts by weight of polypropylene, 5-15 parts by weight of acicular wollastonite, 0.5-1 part by weight of dispersant, 0.5-1 part by weight of lubricant, 1-4 parts by weight of coupling agent, and 0.3-1 part by weight of antioxidant.

[0009] Preferably, the polypropylene is one or more of general grade, impact-resistant grade, transparent grade, high-crystallization grade, alloy grade, or special grade.

[0010] Further, the acicular wollastonite is 1500-3500 mesh.

[0011] Further, the dispersant is one or more of polyacrylic acid sodium salt, sodium pyrophosphate, sodium hexametaphosphate, and metal soaps.

[0012] Further, the lubricant is one or more of stearic acid, polyethylene wax, EBS, and erucic acid amide.

[0013] Further, the coupling agent comprises one of silane coupling agent, titanate, and aluminate.

[0014] A preparation method of a light high-temperature-resistant high-rebound perforated foaming material, the method being as follows:

[0015] (1) The polypropylene, dispersant, lubricant, coupling agent, and antioxidant are weighed and put into a low-speed stirrer for blending at a stirring speed of 20-50 r / min for 20 minutes, then are added into a double-screw extruder for mixing uniformly, and the acicular wollastonite is added from the side feeding, and the mixture is subjected to melting plasticization, kneading mixing, extrusion, cooling, granulation, and drying to obtain a primary product;

[0016] (2) The primary product is extruded into a suitable plate through a single-screw extruder to obtain a secondary product;

[0017] (3) The secondary product is put into a mold pressing foaming mold, and a light high-temperature-resistant high-rebound perforated foaming material is prepared by using mold pressing foaming and supercritical fluid technology.

[0018] Further, in the step (1), the head temperature of the double-screw extruder is set to 210℃, the extrusion speed is 450 r / min, and the preparation process temperature of each zone is as follows: Zone 1, 150℃; Zone 2, 200℃; Zone 3, 215℃; Zone 4, 215℃; Zone 5, 215℃; Zone 6, 220℃; Zone 7, 220℃; Zone 8, 220℃; Zone 9, 220℃; Zone 10, 220℃; Zone 11, 220℃; and Zone 12, 220℃.

[0019] Further, the temperature of the die of the single screw extruder in step (2) is set to 190 DEG C, the extrusion speed is 350 r / min, and the preparation process temperature of each zone is as follows: zone 1 150 DEG C, zone 2 200 DEG C, zone 3 200 DEG C, zone 4 200 DEG C, zone 5 200 DEG C, zone 6 200 DEG C, zone 7 200 DEG C, zone 8 200 DEG C, zone 9 200 DEG C, zone 10 200 DEG C, zone 11 200 DEG C, and zone 12 200 DEG C.

[0020] Further, the specific steps of step (3) are as follows: the secondary product is placed into a mold pressing foaming mold, the temperature in the mold of the mold pressing machine is controlled to be between 150 DEG C and 158 DEG C, the pressure of the supercritical fluid injected into the mold is 8-12 MPa, the temperature and pressure are kept constant for 30-90 min, and then the pressure is released to normal pressure at a speed greater than 20 MPa / s;

[0021] Preferably, the supercritical fluid of the present application is nitrogen.

[0022] Beneficial effects:

[0023] The present application provides a lightweight high-temperature-resistant high-resilience open-cell foaming material and a preparation method thereof, wherein high-melt-strength polypropylene, acicular wollastonite, a dispersing agent, a lubricant, a coupling agent and an antioxidant are blended to obtain a primary product, the primary product is placed into a single screw extruder to obtain a secondary product, the secondary product is placed into a mold pressing foaming mold, supercritical gas is injected into the mold, and the mold is opened rapidly after pressure keeping, with the diffusion of the gas, the solubility of the gas in the secondary product decreases, leading to the nucleation of bubble growth, so that the product is foamed, and the apparent density decreases; the acicular wollastonite plays a role of perforation in the foaming process, the two ends are acicular, with the growth of the cells, the sharp end simultaneously perforates the cells, so that the open-cell rate is increased, and the foaming material becomes a full open-cell material; meanwhile, the thermal conductivity of the material is low, and the temperature resistance of the product can be effectively improved.

[0024] Specifically, the advantages of the lightweight high-temperature-resistant high-resilience open-cell foaming material disclosed by the present application include:

[0025] (1) The open-cell foaming material prepared by the present application has high temperature resistance and can be used under the condition of a temperature of 120 DEG C and high humidity;

[0026] (2) The open-cell foaming material prepared by the present application has a microcell structure of interpenetrating network and high resilience, and can be repeatedly used;

[0027] (3) The formula and method of the present application are simple, the foaming pressure required in the production process is low, the material is easy to shape, general foaming equipment can be used for production, and industrialized production is facilitated.

[0028] It is to be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter. For example, reference to "a polymer" or "one polymer" in one or more places in the specification are not necessarily excluded from other embodiments of the application to reference "one or more polymer" or "one, two, three, or more polymers" because such reference is expected to be interpreted to mean "at least one" or "one or more."

[0029] The foregoing and other aspects, embodiments and features of the present teachings are more fully described below, as described in the detailed description of the application. Additional aspects, embodiments and features of the present teachings will become apparent from the following description, of the application whose embodiments will be described, and will be realized by persons of ordinary skill in the art and others, based on the concerted teachings of the application. The application may, however, best be understood by referring to the following description and accompanying drawings that form a part of this application.

[0030] The foregoing and other aspects, embodiments and features of the present teachings are more fully described below, as described in the detailed description of the application. Additional aspects, embodiments and features of the present teachings will become apparent from the following description, of the application whose embodiments will be described, and will be realized by persons of ordinary skill in the art and others, based on the concerted teachings of the application. The application may, however, best be understood by referring to the following description and accompanying drawings that form a part of this application. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical, or nearly identical, component that is illustrated in various figures is represented with a like numeral. For purposes of clarity, not every component is called out in every drawing. There is a description of embodiments of aspects of the application by way of example and with reference to the drawings in which:

[0032] Foamability : (a) cell electron micrograph of Comparative Example 2; (b) cell electron micrograph of Comparative Example 3; (c) cell electron micrograph of Comparative Example 6; (d) cell electron micrograph of Example 1; (e) cell electron micrograph of Example 2; (f) cell electron micrograph of Example 3.

[0033] Rebound resilience : compressive stress-strain curve of Example 1. DETAILED DESCRIPTION

[0034] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the embodiments of the present application and the drawings. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by persons of ordinary skill in the art without creative effort belong to the protection scope of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the common meanings of the technical terms or scientific terms to those skilled in the art.

[0035] The terms "first", "second", and similar terms used in the specification and claims of the present patent application do not denote any order, quantity, or importance, but are used to distinguish different constituent parts. Also, the singular forms "a", "an", and "the" do not denote the quantity unless the context clearly indicates otherwise. The terms "comprise", "comprising", and similar terms mean that the elements or objects preceding the word "comprise" or "comprising" encompass the features, integers, steps, operations, elements, and / or components listed after the word "comprise" or "comprising" and do not exclude one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The terms "upper", "lower", "left", "right", and the like are used only to indicate relative positions, and when the absolute positions of the described objects change, the relative positions may also change accordingly.

[0036] Based on the prior art scheme of preparing the components of the open-cell foam material by simple blending extrusion to prepare the open-cell foam material, there are problems of large foaming pressure, difficulty in meeting the safety requirements of industrial production, and difficulty in meeting the production pressure in the high-temperature environment of industrialized production, resulting in the problems of difficulty in large-scale production, difficulty in reuse, and poor open-cell condition of the prepared foaming product; the present application aims to solve the above problems, and provides a lightweight high-temperature-resistant high-resilience open-cell foam material and a preparation method thereof. The method prepares a primary product by blending high-melt-strength polypropylene with acicular wollastonite, a dispersing agent, a lubricant, a coupling agent, and an antioxidant, extrudes the primary product into a secondary product by using a single-screw extruder, and finally puts the secondary product into a mold pressing and foaming mold, and foams by passing supercritical nitrogen gas, so that the temperature resistance of the open-cell foam material is improved, the open-cell foam material can be used under high temperature and high humidity conditions, has high resilience, can be reused, and is convenient for large-scale industrial production.

[0037] The raw materials and reagents used in the embodiments of the present application are commercially available. The polypropylene used in the present application needs to be selected from a special grade of high-melt-strength raw material, and therefore WB140 from Nordic Chemical is particularly limited.

[0038] Example 1: Preparation of lightweight high-temperature-resistant high-resilience open-cell foam material

[0039] (1) Take 855 g of polypropylene, 10 g of dispersant, 10 g of lubricant, 20 g of coupling agent, 5 g of antioxidant into a low-speed blender and blend at a stirring speed of 40 r / min for 20 minutes, then add into a twin-screw extruder, set the head temperature of the twin-screw extruder to 210℃, the extrusion speed to 450 r / min, and the preparation process temperature of each zone to: Zone 1 150℃, Zone 2 200℃, Zone 3 215℃, Zone 4 215℃, Zone 5 215℃, Zone 6 220℃, Zone 7 220℃, Zone 8 220℃, Zone 9 220℃, Zone 10 220℃, Zone 11 220℃, and Zone 12 220℃; and add 100 g of 2500 mesh acicular wollastonite from the side feed, melt and plasticize, knead and mix, extrude, cool, cut, and dry the mixture to obtain a primary product;

[0040] (2) Extrude the primary product into a sheet through a single-screw extruder, set the die temperature of the single-screw extruder to 190℃, the extrusion speed to 350 r / min, and the preparation process temperature of each zone to: Zone 1 150℃, Zone 2 200℃, Zone 3 200℃, Zone 4 200℃, Zone 5 200℃, Zone 6 200℃, Zone 7 200℃, Zone 8 200℃, Zone 9 200℃, Zone 10 200℃, Zone 11 200℃, and Zone 12 200℃, to obtain a secondary product;

[0041] (3) Put the secondary product into a mold pressing foaming mold, control the temperature in the mold of the mold pressing machine to be 154℃, the pressure of the supercritical fluid nitrogen gas injected into the mold to be 10 MPa, and the constant temperature and pressure in the mold for 60 min, then depressurize to normal pressure at a speed of 25 MPa / s to obtain a lightweight high-temperature-resistant high-resilience open-cell foaming material.

[0042] Examples 2-3 and Comparative Examples 1-7 differ from Example 1 only in the change of product formula in the preparation of a lightweight high-temperature-resistant high-resilience open-cell foaming material, and the preparation steps and conditions are consistent with those of Example 1. The specific primary product formula is shown in Table 1 below:

[0043] Table 1 (unit: g)

[0044]

[0045]

[0046] Test: Performance test of lightweight high-temperature-resistant high-resilience open-cell foaming material

[0047] The lightweight high-temperature-resistant high-resilience open-cell foaming materials prepared in Examples 1-3 and Comparative Examples 1-11 were tested for various properties according to the method for testing the density of plastics in ISO 1183, and the test was repeated three times. The test results are shown in Table 2 below:

[0048] Table 2

[0049] Density (g / cm 3 )]]> Cell opening Example 1 Good Fully open 0.028 29 Example 2 Relatively good Semi-open 0.031 27 Example 3 Fair Semi-open 0.042 18.5 Comparative Example 1 Poor Closed 0.049 23 Comparative Example 2 Poor Closed 0.067 10 Comparative Example 3 Poor Closed 0.060 17 Comparative Example 4 Poor Closed 0.061 15 Comparative Example 5 Poor Closed 0.051 20 Comparative Example 6 Poor Closed 0.062 15 Comparative Example 7 Poor Closed 0.045 22 Comparative Example 8 Poor Closed 0.066 12 Comparative Example 9 Poor Closed 0.064 14 Comparative Example 10 Poor Closed 0.047 18 Comparative Example 11 Poor Closed 0.045 16 Figures 1-2 ​

[0050] By ​ , Table 2 can be obtained:

[0051] 1、From the test data of examples 1-3 and comparative examples 1, 3, 4, 5 in the above table, the open-cell foamed materials obtained by examples 1-3 have smaller density, higher foaming ratio and higher resilience compared with comparative examples 1, 3, 4, 5. It is proved that the ratio of polypropylene and acicular wollastonite in examples 1-3 is more optimal, and the material with good open-cell effect, good resilience and high foaming rate can be obtained. Among them, examples 1-3 respectively compare the influence of different acicular wollastonite contents on the open-cell foamed material, the foamed material prepared in example 2 finally forms a semi-open-cell state, and it is difficult to fully open-cell at low pressure, which is due to the small amount of wollastonite, resulting in fewer needle tips, and not all cells can be perforated; in example 3, the content of acicular wollastonite is increased, but the foaming ratio is low, and the open-cell condition is also semi-open-cell, and the product resilience is general, which is due to the large amount of wollastonite added, which has a certain side effect on foaming, and when too much is added, dispersion is a problem, and wollastonite is difficult to disperse, resulting in poor foaming performance; the product foamed in example 1 is fully open-cell, high resilience and high foaming ratio.

[0052] 2、Comparative example 2 does not add acicular wollastonite to the material, and comparative example 6 replaces acicular wollastonite with the same mass of elastomer EPDM in the material, and the foamed materials finally formed are all closed-cell, and the resilience is poor, which is due to the fact that the open-cell structure is formed by blending soft and hard phases, and a higher foaming pressure is required, while the pressure in the production of the material of the present application is much lower than the pressure required for the open-cell of comparative example 6; the mass of the elastomer added in comparative example 7 is more than that in comparative example 6, but the performance of each item is poorer than that of the material prepared in the examples. In comparative examples 10 and 11, the acicular wollastonite used is 1000 mesh and 5000 mesh respectively, because the mesh number of the acicular wollastonite used in comparative example 10 is small, it cannot pierce the holes and cannot be effectively dispersed, while the mesh number used in comparative example 11 is too large, the holes of the material prepared are too large, resulting in poor material performance.

[0053] 3、In comparative example 8, the polypropylene used is general grade polypropylene, and in comparative example 9, the wollastonite added is non-acicular wollastonite, which cannot pierce the cells from both ends during foaming, so the open-cell foamed material is closed-cell, with small foaming ratio and poor resilience. From the above comparison, it can be seen that the material prepared in example 1 is fully open-cell, high resilience and high foaming ratio, which proves that example 1 is the optimal ratio of the present application, and the open-cell effect is the best and the material performance is the best only under the formula of example 1.

[0054] While the application has been described by way of example with reference to preferred embodiments, it is to be understood that this application is not limited to the embodiments disclosed, but is intended to cover various arrangements or modifications thereof. Therefore, other modifications and embodiments of the application will occur to those skilled in the art upon reading the above description and which are intended to be within the scope of the application. It is intended that the scope of the application be defined by the following claims.

Claims

1. A lightweight, high-temperature resistant, high-resilience open-cell foam material, characterized in that, The material comprises the following components: 78-93 parts by weight of polypropylene, 5-15 parts by weight of acicular wollastonite, 0.5-1 parts by weight of dispersant, 0.5-1 parts by weight of lubricant, 1-4 parts by weight of coupling agent, and 0.3-1 parts by weight of antioxidant. The polypropylene is Borealis' WB140 model. The acicular wollastonite is 2500 mesh; The preparation method of the material is as follows: (1) Weigh polypropylene, dispersant, lubricant, coupling agent and antioxidant and put them into a low speed mixer and mix for 20 minutes. Then add them into a twin screw extruder and mix evenly. Add needle-shaped wollastonite from the side feed. The mixture is melted, plasticized, kneaded and mixed, extruded, cooled, pelletized and dried to obtain the primary product. (2) The primary product is extruded into a suitable sheet using a single-screw extruder to obtain the secondary product; (3) The secondary product is placed in a molding foam mold, and a lightweight, high-temperature resistant, high-resilience open-cell foam material is prepared by molding foam and supercritical fluid technology. The specific operation of (3) is as follows: the secondary product is placed in the molding foam mold, the temperature inside the molding mold is controlled between 150-158℃, the pressure of the supercritical fluid injected into the mold is 8-12MPa, the temperature and pressure are kept constant for 30-90min, and then the pressure is released to normal pressure at a rate greater than 20MPa / s.

2. The lightweight, high-temperature resistant, high-resilience open-cell foam material according to claim 1, characterized in that, The dispersant is one or more of sodium polyacrylate, sodium pyrophosphate, sodium hexametaphosphate, and metal soaps.

3. The lightweight, high-temperature resistant, high-resilience open-cell foam material according to claim 1, characterized in that, The lubricant is one or more of stearic acid, polyethylene wax, EBS, and erucamide.

4. The lightweight, high-temperature resistant, high-resilience open-cell foam material according to claim 1, characterized in that, The coupling agent includes one of silane coupling agents, titanate esters, and aluminate esters.

5. The lightweight, high-temperature resistant, high-resilience open-cell foam material according to claim 1, characterized in that, The die head temperature of the twin-screw extruder in (1) is set to 210℃, the extrusion speed is 450r / min, and the preparation process temperature of each zone is: Zone 1 150℃, Zone 2 200℃, Zone 3 215℃, Zone 4 215℃, Zone 5 215℃, Zone 6 220℃, Zone 7 220℃, Zone 8 220℃, Zone 9 220℃, Zone 10 220℃, Zone 11 220℃, Zone 12 220℃.

6. The lightweight, high-temperature resistant, high-resilience open-cell foam material according to claim 5, characterized in that, The die temperature of the single screw extruder in (2) is set to 190℃, the extrusion speed is 350r / min, and the preparation process temperature of each zone is: Zone 1 150℃, Zone 2 200℃, Zone 3 200℃, Zone 4 200℃, Zone 5 200℃, Zone 6 200℃, Zone 7 200℃, Zone 8 200℃, Zone 9 200℃, Zone 10 200℃, Zone 11 200℃, Zone 12 200℃.

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