阅读说明：本技术 一种发泡材料及其制备方法 (Foaming material and preparation method thereof ) 是由 王光海 杨庆锋 于 2021-07-27 设计创作，主要内容包括：本发明公布了一种发泡材料的制备方法,操作步骤包括将原料混匀、密炼造粒、挤出、辐射交联、模压发泡等步骤制备得到发泡材料,通过本方法生产得到的发泡材料具备无毒无味性、优异的防潮性、保温隔热性、减震隔音性、成型加工性,还具有质轻、良好的柔软性、回弹性、耐候性和耐化学腐蚀性等。(The invention discloses a preparation method of a foaming material, which comprises the following operation steps of uniformly mixing raw materials, banburying granulation, extrusion, radiation crosslinking, mould pressing foaming and the like to prepare the foaming material.)

1. A preparation method of a foaming material comprises the following steps:

s1: taking 150-200 parts of a high polymer foaming matrix, 5-10 parts of a foaming agent, 0.5-2.0 parts of a foaming auxiliary agent, 1-4 parts of an antioxidant and 5-6 parts of a heat conducting agent, and uniformly stirring in a stirrer to obtain a premix; wherein the polymer foaming matrix comprises 60-80% of low-density components and 20-40% of high-density components;

s2: transferring the premix material in the S1 to an internal mixer, and carrying out mixing treatment to obtain softened pellets;

s3: carrying out casting or calendering treatment on the softened pellets in the S2 to obtain a sheet;

s4: irradiating the sheet in the S3 by using a high-energy ray to obtain a sheet to be foamed;

s5: and cutting the to-be-foamed sheet in the step S4 into a foamed master sheet, placing the foamed master sheet into a closed container to expand and shape, and cooling to obtain the foamed material.

2. The method as claimed in claim 1, wherein the polymeric foaming matrix is one or more selected from EVA, PE, PP, and TPE.

3. The method of claim 2, wherein the polymeric foam matrix is one or more of EVA and PE.

4. The method of claim 1, wherein the temperature of the banburying process in S2 is 100-125 ℃.

5. The method of claim 1, wherein in S4, the high-energy radiation is selected from one of electron radiation, gamma radiation and ultraviolet radiation.

6. The method of claim 1, wherein in S5, the expansion ratio of the foam master sheet is controlled to be 100% to 500%.

7. The method of claim 1, wherein the amount of the foaming agent in S1 is 8-10 parts.

8. A foamed material produced by the method for producing a foamed material according to any one of claims 1 to 7.

Technical Field

The invention belongs to the technical field of preparation of high polymer materials, and particularly relates to a foaming material and a preparation method thereof.

Background

At present, the application range of the foaming material is getting larger and larger, and the foaming material widely relates to the industries of electronics, household appliances, automobiles, sports and leisure and the like. The soft foaming material is prepared by adding auxiliary materials such as a catalyst, a foam stabilizer, a foaming agent and the like into raw materials such as plastics (PE, EVA and the like) and rubber (SBR, CR and the like), and enabling a large number of fine cells, volume increase and density reduction to appear in the plastics and the rubber through physical foaming or chemical foaming. The soft foaming material has light weight and good softness, has the functions of buffering, sound absorption, shock absorption, heat preservation, filtration and the like, and is widely applied to the industries of electronics, household appliances, automobiles, sports, leisure and the like. The production of the foaming material comprises a cross-linking process and a foaming process, wherein a chemical cross-linking agent is usually adopted in the cross-linking process or a three-dimensional complex cross-linking network is formed by cross-linking a high-molecular polymer by an irradiation method, so that the polymer can lock bubbles in the polymer to form the foaming material during foaming; although the foamed material has been an important material in the field of vibration damping and sound insulation, and generally, the foam is used for realizing vibration damping and sound insulation by using air bubbles in the material, the technical development of optimizing the performance based on the internal consumption of the polymer foamed material is still relatively small.

For example, chinese patent application No. CN201110150764.5 discloses a high resilience flame retardant antistatic foamed polyethylene material, which comprises a foamed base, a foaming agent, a nucleating agent, a flame retardant and an antistatic agent, wherein the main component of the flame retardant is a brominated flame retardant, the main component of the antistatic agent is conductive carbon black, and the high resilience flame retardant antistatic foamed polyethylene material is prepared by mixing, crosslinking and molding the foamed base, the foaming agent, the nucleating agent, the flame retardant and the antistatic agent; in the disclosure, a foaming matrix, i.e., a high molecular polymer, and various components are mixed, and then cross-linked and molded to obtain a foaming material, which has disadvantages of low internal friction, poor damping effect, poor sound insulation effect, and the like.

Disclosure of Invention

In order to solve the technical problems of low internal consumption, poor damping effect and poor sound insulation effect in the background art, the invention aims to provide a foaming material.

The second purpose of the invention is to provide a preparation method of the foaming material.

The technical scheme of the invention is as follows:

a preparation method of a foaming material comprises the following steps:

s1: taking 150-200 parts of a high polymer foaming matrix, 5-10 parts of a foaming agent, 0.5-2.0 parts of a foaming auxiliary agent, 1-4 parts of an antioxidant and 5-6 parts of a heat conducting agent, and uniformly stirring in a stirrer to obtain a premix; wherein the polymer foaming matrix comprises 60-80% of low-density components and 20-40% of high-density components;

s2: transferring the premix material in the S1 to an internal mixer, and carrying out mixing treatment to obtain softened pellets;

s3: carrying out casting or calendering treatment on the softened pellets in the S2 to obtain a sheet;

s4: irradiating the sheet in the S3 by using a high-energy ray to obtain a sheet to be foamed;

s5: and cutting the to-be-foamed sheet in the step S4 into a foamed master sheet, placing the foamed master sheet into a closed container, expanding, shaping and cooling to obtain the foamed material.

In the prior art, the strength of the foam material is usually improved by improving the crosslinking degree of the high polymer material, so that the shock absorption performance of the foam material is realized; however, the degree of crosslinking of the foamed polymer material cannot be increased particularly, because too high a degree of crosslinking makes it difficult for the foaming agent to open the polymer chains crosslinked together to form uniform pores in the subsequent foaming step, and the cells, if not formed, affect the vibration damping and sound insulation properties of the foamed product.

In the above technical scheme of the invention, the high-density component is mainly a high-molecular polymer with high crystallinity or few branched chains, which can be similar to high-density polyethylene; generally, in order to obtain a better crosslinking degree, the adopted foaming matrix is generally a high molecular polymer with multiple branched chains, and the foaming material obtains better crosslinking through developed branched chains, so that the high molecular polymer obtains better shock absorption performance and sound insulation performance. However, the inventors have found that by adding a certain amount of a high-density component to a high-molecular polymer, a foamed material having better vibration-damping properties and sound-insulating properties is obtained than by adding no high-density component. Because the raw materials are mixed and milled uniformly after a certain amount of high-density components are added, the raw materials are extruded or rolled into sheets for crosslinking treatment, and then high-energy ray irradiation treatment is carried out to crosslink the macromolecules in the sheets, the low-density components with a large number of branched chains and part of the high-density components are crosslinked in the operation to form a three-dimensional crosslinking network; then, the sheet material which is crosslinked in the previous step is heated and pressurized in a closed container, so that the sheet material is softened, the foaming agent in the sheet material is decomposed into gas, a large number of bubbles are formed in the softened sheet material, and the gas can be firmly locked in the sheet material to form a perfect circle closed hole due to the early existence of a three-dimensional crosslinking network; the sheet material in the closed container forms a foaming material (softened molten state) in a shape of the inner wall of the container, and then the cooling is carried out to solidify the material in the container, at this time, the polymer chains formed by the part of the uncrosslinked or partially locally crosslinked high-density component in the inner surface area of the molten material are converged to form crystals due to small steric hindrance, the crystals belong to the areas with high density in the foaming material, when the foaming material receives mechanical impact and sound wave impact, the energy caused by the impact is transmitted to the far direction along the chain or the crosslinked network, and the energy is prevented from being transmitted due to the existence of the crystal areas, so that the energy is stored in the foaming material, and the energy of the previous time is not dissipated to transmit the energy of the next time, and the steps are repeated, the energy not released is eventually consumed by the self-friction of the system and converted into heat. The existence of the phenomenon improves the shock absorption and sound insulation performance of the foaming material provided by the invention, and the heat generated by internal consumption can improve the heat conduction performance of the foaming material due to the added heat conducting agent, so that the heat energy is rapidly dissipated, and the aging of the foaming material cannot be accelerated due to the internal consumption.

Moreover, the invention has obvious advantages in foaming performance of the product compared with the method without adding the high-density component after adding the high-density component. The inventor considers that the cross-linking is in transition suspicion through long-term research, because in the technical transformation of replacing a chemical foaming agent by high-energy rays in the prior art, more foaming agents must be added in the preposed material mixing process, in the subsequent treatment process, the pressure of a mould is properly reduced to solve the problem, otherwise, the situation of incomplete foam is easy to occur, and the performance test of the product is lower than the expectation. The inventors considered that the main reason for the above phenomenon is that the raw material having a high degree of branching is easily crosslinked under the excitation of high-energy rays and is easily excessively crosslinked, that is, a stable three-dimensional network structure is formed prematurely before the product is foamed, which is disadvantageous for the formation of cells during foaming, and even if the foaming agent is decomposed into a large amount of gas uniformly under a high temperature condition, it is difficult to support the material and form a foamed material having a uniform distribution of pores of a stable structure, which involves the above adjustment, and the quality of the adjusted product is lower than expected. Therefore, the invention adds a certain proportion of high-density component in the formula, the high-density component is the same as the original component in chemical composition, and the branched chain degree on the molecular structure is low (without long branched chain, with or without short branched chain), and the high-density component is mainly linear component. The high-density component and the low-density component are reasonably combined and form an integral structure after being subjected to blending, banburying and even open milling treatment, and the components of the integral structure can generate crosslinking with better relative degree when being excited by high-energy rays, namely, the integral structure can not only stabilize the self-locked bubbles, but also be propped up by the bubbles to better form the foaming material, and after the step of optimization, the consumption of the foaming agent can be saved and the pressure of a mould can be properly improved, so that the foaming material with better performance can be better generated.

Preferably, in the above technical solution, the polymer foaming matrix is selected from one or more of EVA, PE, PP, and TPE.

Preferably, in the above technical solution, the polymer foaming matrix is one or more of EVA and PE.

Preferably, the heat conducting agent is one or more selected from the group consisting of alumina powder, graphite, magnesium oxide, calcium silicate, copper powder, and aluminum nitride.

Preferably, in the step S2, the temperature in the banburying process is 110 to 125 ℃.

In S4, the high-energy radiation is preferably one selected from the group consisting of electron radiation, gamma radiation, and ultraviolet radiation.

Preferably, in S5, the expansion ratio of the foam master is controlled to be 100% to 500%.

Preferably, the method further comprises the step of open-mixing the softened pellets with an open mill between S2 and S3.

Preferably, in the above technical means, in S1, the amount of the foaming agent is 8 to 10 parts.

The invention also provides a foaming material, wherein the foaming matrix of the foaming material is selected from one of EVA, PE, PP, TPE, TPU, PU and rubber, and then is supplemented with a foaming agent, a foaming auxiliary agent, an antioxidant and a heat conducting agent to prepare the foaming material through the steps of banburying, extrusion, high-energy ray irradiation, expansion shaping in a closed container and the like; the foaming material has the advantages of no toxicity, no odor, excellent moisture resistance, heat insulation, shock absorption, sound insulation, molding processability, light weight, good flexibility, rebound resilience, weather resistance, chemical corrosion resistance and the like.

In conclusion, the beneficial effects of the invention are as follows:

1. according to the invention, a certain amount of high-density components are added into the high-molecular foaming matrix, so that the internal consumption of the foaming material is increased when the foaming material receives the impact of an object or sound, and the shock absorption performance and the sound insulation performance of the foaming material are improved;

2. the method treats the sheet to be foamed in a radiation crosslinking mode, and has the advantages of good crosslinking effect, controllable crosslinking degree and good reproducibility; meanwhile, the cross-linking agent is prevented from remaining in the foaming product, so that potential safety hazards to the contacted human body are avoided;

3. according to the invention, the cross-linked sheet is foamed by a mould pressing foaming technology, so that the processing of the foamed sheet is simplified, and the prepared foamed material has uniform and fine foam pores;

4. the foaming material provided by the invention has higher crosslinking degree, excellent mechanical property of a finished product and good effect when being applied to climbing mats, yoga mats and the like.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the following detailed description will be made with reference to the embodiments of the present invention, which are only for explanation and not for limitation of the present invention.

Example 1

A preparation method of a foaming material comprises the following steps:

s1: 120 parts of EVA powder, 80 parts of PE powder, 10 parts of AC, 2.0 parts of nano zinc oxide and 4 parts of tetrakis [ methyl- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Uniformly stirring pentaerythritol ester and 5 parts of nano-alumina in a stirrer to obtain a premix, stirring for 30min to obtain a uniformly mixed material, and paying attention to the fact that the temperature of the stirrer cannot be too high to avoid gelatinization of raw materials in the stirrer; the density of the EVA powder is 0.929-0.948 g/cm³The density of the PE powder is 0.941-0.965 g/cm³；

S2: transferring the premix material in S1 to an internal mixer, and carrying out mixing treatment at 105 ℃ to obtain softened pellets;

s3: calendering the softened pellets in S2 to obtain a sheet;

s4: irradiating the sheet in the S3 by using high-energy electron rays, wherein the radiation dose is 11KGy, and obtaining a sheet to be foamed;

s5: and (3) cutting the to-be-foamed sheet in the step (S4) into a foamed master sheet, placing the foamed master sheet into a closed container, expanding and shaping the foamed master sheet at the temperature of 120 ℃ under the pressure of 10MPa for 0.5min, and then cooling to 80 ℃ to obtain the foamed material.

Example 2

A preparation method of a foaming material comprises the following steps:

s1: taking 200 parts of PE powder, 10 parts of AC, 2.0 parts of nano zinc oxide and 4 parts of tetra [ methyl- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Uniformly stirring pentaerythritol ester and 5 parts of nano-alumina in a stirrer to obtain a premix, stirring for 30min to obtain a uniformly mixed material, and paying attention to the fact that the temperature of the stirrer cannot be too high to avoid gelatinization of raw materials in the stirrer; wherein the PE is 60% of low densityThe density range of the low-density component is 0.910-0.925 g/cm³The density of the high-density component is 0.941-0.965 g/cm³；

S2: transferring the premix material in S1 to an internal mixer, and carrying out mixing treatment at 110 ℃ to obtain softened pellets;

s3: calendering the softened pellets in S2 to obtain a sheet;

s4: irradiating the sheet in the S3 by using high-energy electron rays, wherein the radiation dose is 10.6KGy, and obtaining a sheet to be foamed;

s5: and (3) cutting the to-be-foamed sheet in the step (S4) into a foamed master sheet, placing the foamed master sheet into a closed container, expanding and shaping the foamed master sheet at the temperature of 130 ℃ under the pressure of 10MPa for 0.5min, and then cooling to 80 ℃ to obtain the foamed material.

Example 3

A preparation method of a foaming material comprises the following steps:

s1: taking 120 parts of PP powder, 80 parts of PE powder, 10 parts of AC, 2.0 parts of nano zinc oxide and 4 parts of tetrakis [ methyl- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Uniformly stirring pentaerythritol ester and 5 parts of nano-alumina in a stirrer to obtain a premix, stirring for 30min to obtain a uniformly mixed material, and paying attention to the fact that the temperature of the stirrer cannot be too high to avoid gelatinization of raw materials in the stirrer; wherein the density of the PP powder is 0.890-0.910 g/cm³The density of the PE powder is 0.941-0.965 g/cm³；

S2: transferring the premix material in S1 to an internal mixer, and carrying out mixing treatment at 108 ℃ to obtain softened pellets;

s3: calendering the softened pellets in S2 to obtain a sheet;

s4: irradiating the sheet in the S3 by using high-energy electron rays, wherein the radiation dose is 15KGy, and obtaining a sheet to be foamed;

s5: and (3) cutting the to-be-foamed sheet in the step (S4) into a foamed master sheet, placing the foamed master sheet into a closed container, expanding and shaping at the temperature of 143 ℃ under the pressure of 9MPa for 0.5min, and cooling to 80 ℃ to obtain the foamed material.

Example 4

A preparation method of a foaming material comprises the following steps:

s1: 120 parts of TPE powder, 80 parts of PE powder, 10 parts of AC, 2.0 parts of nano zinc oxide and 4 parts of tetrakis [ methyl- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Uniformly stirring pentaerythritol ester and 5 parts of nano-alumina in a stirrer to obtain a premix, stirring for 30min to obtain a uniformly mixed material, and paying attention to the fact that the temperature of the stirrer cannot be too high to avoid gelatinization of raw materials in the stirrer; the density of the TPE powder is 0.91-0.922 g/cm³The density of the PE component is 0.941-0.965 g/cm³；

S2: transferring the premix material in S1 to an internal mixer, and carrying out mixing treatment at 105 ℃ to obtain softened pellets;

s3: calendering the softened pellets in S2 to obtain a sheet;

s4: irradiating the sheet in the S3 by using high-energy electron rays, wherein the radiation dose is 16.9KGy, and obtaining a sheet to be foamed;

s5: and (3) cutting the to-be-foamed sheet in the step (S4) into a foamed master sheet, placing the foamed master sheet into a closed container, expanding and shaping the foamed master sheet at the temperature of 130 ℃ under the pressure of 10MPa for 0.5min, and then cooling to 80 ℃ to obtain the foamed material.

Comparative example

A high-resilience flame-retardant antistatic foamed polyethylene material comprises a foaming base body, a foaming agent, a nucleating agent, a flame retardant and an antistatic agent, wherein the foaming base body is EVA powder, the main component of the flame retardant is a brominated flame retardant, the main component of the antistatic agent is conductive carbon black, and the high-resilience flame-retardant antistatic foamed polyethylene material is prepared by mixing the foaming base body, the foaming agent, the nucleating agent, the flame retardant and the antistatic agent at the temperature of 110-125 ℃ for 30min, extruding the mixture by an extruder to form a sheet, cutting the sheet after irradiation crosslinking, and molding and pressing the sheet into a foamed material in a molding press under the conditions of 10MPa pressure and 120 ℃.

The inventors conducted the following experiments on the foamed materials obtained in the above examples:

(1) determination of ball rebound: measured according to GB/T6670-2008 "determination of ball rebound resilience of Flexible foam Polymer".

From the above experimental data, it is not obvious that the foam material produced by installing the technical scheme provided by the invention has better elastic property than that produced by the prior art.

(2) Determination of tensile Strength: the thickness d and width b (mm) of the faying surface of the test specimen are measured, then the test specimen is symmetrically clamped in an upper clamp and a lower clamp, the distance from the clamping position to the faying end is (50 +/-1) mm, and a test instrument is started to load the test specimen at a stable speed of (5 +/-1) mm/min. Recording the maximum load p (n) of shear failure of the specimen; calculating formula: δ = p/(b × d) where δ is the tensile strength (MPa), and the area used in the calculation is the original cross-sectional area of the specimen at break, not the post-break port cross-sectional area.

The tensile strength of the foamed materials in the examples is obtained by simple calculation of the data, the tensile strength of the foamed materials formed by different raw materials is different, and the toughness of the product of the invention is stronger as shown by the comparison of the tensile strength of the example 2 and the tensile strength of the comparative example.

(3) Measurement of soundproofing effect:

the test method comprises the following steps: GB/T19889.3-2005

And (3) testing temperature: 25 deg.C

Relative humidity: 63 percent of

Area of standard sample: 10.5m2

Receiving chamber volume: 111m3

The sound insulation tests were performed on a control group and an experimental group respectively, the control group was made of the foam material provided in the comparative example, the experimental group was made of the foam material provided in example 1, and the thickness of the foam material and the area covered on the ground were the same for the control group and the experimental group. The experimental data are shown in the following table.

From the above analysis, it can be seen that the sound insulation effect of the foam material provided by the present invention is slightly better than that of the control group in both the high frequency region and the low frequency region.

Finally, it should be noted that: although the present invention has been described in detail with reference to the embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.