CN116120621B - Triboelectric regenerated product based on waste polypropylene and preparation method thereof - Google Patents
Triboelectric regenerated product based on waste polypropylene and preparation method thereof Download PDFInfo
- Publication number
- CN116120621B CN116120621B CN202211642787.2A CN202211642787A CN116120621B CN 116120621 B CN116120621 B CN 116120621B CN 202211642787 A CN202211642787 A CN 202211642787A CN 116120621 B CN116120621 B CN 116120621B
- Authority
- CN
- China
- Prior art keywords
- polypropylene
- triboelectric
- foaming
- waste
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
- C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
- C08J9/122—Hydrogen, oxygen, CO2, nitrogen or noble gases
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B9/00—Making granules
- B29B9/02—Making granules by dividing preformed material
- B29B9/06—Making granules by dividing preformed material in the form of filamentary material, e.g. combined with extrusion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/32—Component parts, details or accessories; Auxiliary operations
- B29C43/58—Measuring, controlling or regulating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/60—Measuring, controlling or regulating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/92—Measuring, controlling or regulating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/32—Component parts, details or accessories; Auxiliary operations
- B29C43/58—Measuring, controlling or regulating
- B29C2043/5816—Measuring, controlling or regulating temperature
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2948/00—Indexing scheme relating to extrusion moulding
- B29C2948/92—Measuring, controlling or regulating
- B29C2948/92504—Controlled parameter
- B29C2948/92704—Temperature
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2203/00—Foams characterized by the expanding agent
- C08J2203/06—CO2, N2 or noble gases
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2203/00—Foams characterized by the expanding agent
- C08J2203/08—Supercritical fluid
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2323/10—Homopolymers or copolymers of propene
- C08J2323/12—Polypropene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2453/00—Characterised by the use of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
Abstract
The application provides a waste polypropylene-based triboelectric regenerated product and a preparation method thereof. The preparation method of the application utilizes a solid-phase shearing and grinding technology to prepare the polypropylene ultrafine powder, and discovers that under the unconventional specific process conditions, the triboelectric regenerated product with better triboelectric performance can be prepared, thereby realizing the high added value recycling of the waste polypropylene.
Description
Technical Field
The application belongs to the technical field of triboelectric materials, and relates to a waste polypropylene-based triboelectric regenerated product and a preparation method thereof, wherein the triboelectric regenerated product can be applied to a triboelectric generator, and particularly the polypropylene is treated by utilizing a mechanochemical reactor disclosed in Chinese patent ZL 95111258.9.
Background
The plastic products have wide application due to the advantages of low price, light weight, good processability and the like, and almost relate to aspects of human production and life. Only 2019, nearly 3.6 million tons of plastic were produced worldwide. Under demand push, global plastic production continues to increase. Among them, polypropylene (PP) is one of the most widely used polymers due to its good mechanical properties, easy processing and low cost. The global PP yield in 2020 reaches 7539.5 ten thousand tons and is widely applied to industries such as building, automobiles, packaging and the like. The PP foam is a good substitute for the traditional polystyrene and polyurethane foam, the PP disposable cutlery box is widely used in the takeaway field, and the PP film plays a great role in packaging of tobacco, food, medicines and the like.
However, PP cannot be degraded in natural environment, and products thereof are wasted and then need to be recycled, otherwise serious environmental pollution is caused. At present, the recovery of the waste PP is mainly focused on physical recovery, namely, the waste PP product obtained by collection is subjected to cleaning, crushing and then melting processing molding. However, because the general linear PP has low melt strength and high crystallinity, the melt strength can be further reduced compared with that of the raw PP by remelting, and because other auxiliary agents, fillers and pigments exist in the waste products, the regenerated products are often poor in performance and can only be degraded for use in low-end fields such as garbage cans, water pipes and the like. In particular, the narrow foaming temperature window is not suitable for preparing recycled foam products, which greatly limits the practical application of PP recycled materials. In order to obtain high-performance PP regenerated products, especially PP regenerated foam, and increase the application range of the PP regenerated products, development of a new process and a new technology for high-quality recycling of waste PP is needed.
Disclosure of Invention
In order to solve the problems in the prior art, the application provides a waste polypropylene-based triboelectric regenerated product and a preparation method thereof, wherein the preparation method utilizes a solid-phase shearing and grinding technology to prepare polypropylene ultrafine powder, and discovers that the product can be prepared into the triboelectric regenerated product with better triboelectric performance under the unconventional specific process condition, thereby realizing the recycling of the waste polypropylene with high added value.
In order to achieve the above object, the present application is realized by adopting the technical scheme comprising the following technical measures.
In one aspect, the application provides a method for preparing a triboelectric recycled product based on waste polypropylene, which mainly comprises the following steps:
(1) The recycled polypropylene waste is used as reclaimed materials for standby after pretreatment including cleaning; wherein the polypropylene waste is composed mainly of isotactic polypropylene (iPP);
(2) Adding the reclaimed materials into a grinding disc-shaped solid-phase mechanochemical reactor for grinding and crushing, and collecting the polypropylene ultrafine powder after grinding is completed; wherein, the technological parameters of the millstone-shaped solid phase mechanochemical reactor are as follows: the milling pressure is 1-10 MPa, the cyclic milling is 1-10 times, and the rotating speed of the millstone is 10-50 revolutions per minute;
(3) The raw materials mainly comprising the following components in parts by weight are mixed and prepared to be used as a mixture:
80 to 100 parts of polypropylene ultrafine powder,
0 to 20 parts of polyolefin elastomer OBC,
wherein the total of the polypropylene ultrafine powder and the polyolefin elastomer OBC is 100 parts;
(4) Mixing and granulating the mixture prepared in the step (3) through a double-screw extruder to obtain composite granules; wherein the technological parameters of the twin-screw extruder are as follows: the temperature from the feed inlet to the die is 160-200 ℃, the temperature interval of each section of screw is not more than 20 ℃, and the screw rotating speed is 50-80 r/min;
(5) Preparing the composite granules obtained in the step (4) into a composite material through a flat vulcanizing machine; wherein the technological parameters of the flat vulcanizing machine are as follows: the pressure is 6-10 Mpa, the upper plate temperature is 180-200 ℃, the lower plate temperature is 180-200 ℃, the hot pressing is carried out for 4-7 min, and the cold pressing is carried out for 3-5 min;
(6) Foaming the composite material obtained in the step (5) through supercritical carbon dioxide to prepare a triboelectric regenerated product; wherein the technological parameters of the supercritical carbon dioxide foaming treatment are as follows: the foaming temperature is 130-140 ℃, and the foaming pressure is 15-25 MPa.
The main object of the present application is to find out the problem of high-value recycling of polypropylene waste by a single accidental search conducted by the present inventors. Heretofore, the applicant of the present application has found that it can promote the processability of polymers for the technical purpose of reprocessing and reusing based on the solid phase shear milling technology for the polymer milling pulverization, and filed and published a series of patents and papers (for example CN1341677 a), but the regenerated products obtained by such technical solutions are generally low-end products, and cannot realize the high-value recycling of polymer waste.
Based on the current situation, the inventor of the application based on the conventional grinding and crushing of the polypropylene ultrafine powder by a millstone-shaped solid-phase mechanochemical reactor, occasionally found that in the process of supercritical carbon dioxide foaming treatment, when foaming is carried out according to the supercritical carbon dioxide foaming process parameters conventionally applicable to the polypropylene material, the obtained regenerated product has serious cell collapse phenomenon, so that the normal regenerated foam product cannot be prepared. For this situation, it will be generally determined by those skilled in the art that since polypropylene is derived from polypropylene waste, the processability of polypropylene is very limited after processing and use without adding other additives/fillers, and although the processability can be improved to some extent based on the solid phase shear milling technique, there is a certain upper limit to the effect, so that it is expected that normal recycled foam products cannot be prepared under the conventional foaming process conditions.
However, the inventor of the application discovered accidentally in one exploration attempt that after the foaming temperature is further remarkably reduced, a regenerated product with normal foaming morphology is prepared, and tested, the regenerated product has better triboelectric performance, the triboelectric performance is further improved along with the reduction of the foaming temperature, and the regenerated product can be directly applied to a triboelectric generator, so that the high-value recycling of polypropylene waste is realized.
It is important to note that in the prior art, the conventionally applicable supercritical carbon dioxide foaming temperature of the polypropylene material is generally considered to be 155 ℃ -170 ℃ (Zhang Zhuang, xu Zhixin, zheng Anna, etc.. The influence of the process temperature on the cell structure of the supercritical CO2 foamed polypropylene [ J ]. The university of North America university: nature science edition, 2010,36 (5): 7.), when the temperature is lower than 155 ℃ and even lower than 140 ℃, the melting of the polymer is insufficient, so that a polypropylene product with normal foaming morphology cannot be obtained, and even the product has a situation that the part does not have the cell morphology due to insufficient foaming. The principle of the polypropylene waste (mainly comprising isotactic polypropylene) used in the application is not known at present, and presumably the polypropylene waste is caused by other impurities contained in the polypropylene waste, because the applicable foaming temperature is changed to 130-140 ℃ after the polypropylene waste is ground and crushed by a millstone-shaped solid-phase mechanochemical reactor.
With reference to the technical scheme provided by the application, the triboelectric regenerated product with good cell morphology is successfully prepared at the foaming temperature of 130-140 ℃, the maximum output voltage of the triboelectric regenerated product can reach 85V, a commercial capacitor with the maximum output voltage of 1 mu F is charged to 6.8V in 100S, and about 60 LED small bulbs can be lightened.
In this context, the polypropylene waste in the step (1) is mainly composed of isotactic polypropylene (iPP), and may be waste products or scrap recycled materials of the isotactic polypropylene (iPP) material, such as commodity transparent packaging films (wherein the cigarette transparent packaging films are most typical), food packaging materials, and the like; or waste products or scrap recovery with isotactic polypropylene at a ratio of not less than 95 wt%.
In one of the technical solutions, the pretreatment in step (1) includes cleaning, which mainly eliminates impurities other than polypropylene, and if necessary, eliminates parts other than polypropylene, and the person skilled in the art can perform specific treatment according to the prior art according to the actual condition of the product or the reclaimed material that needs to be recycled. Further, the pretreatment further comprises treating the polypropylene powder or polypropylene crumb suitable for being put into a pan-shaped solid-phase mechanochemical reactor for grinding and crushing, and the person skilled in the art can know through the mechanochemical reactor disclosed in the prior patent ZL 95111258.9 by the applicant of the present application that the device is based on the principle of grinding and crushing by a grinding pan with high shearing force, so that the polypropylene granule with the average particle diameter of not more than 5mm can be treated and crushed, for example, by a high-speed impact crusher, a jaw crusher, a cryomill or other conventional devices of the prior crushing technology; or when the polypropylene waste in the form of film is treated into plastic film strips with the length of not more than 1-5 cm.
In this context, the millstone-shaped solid-phase mechanochemical reactor in step (2) is a mechanochemical reactor disclosed in a patent ZL 95111258.9 issued to the applicant of the present application, wherein the millstone-shaped solid-phase mechanochemical reactor further comprises other conventional process parameters, and the method for preparing polymer ultrafine powder by using the millstone-shaped mechanochemical reactor disclosed in a patent CN1341677a issued to the applicant of the present application can be further referred to, for example, by controlling the temperature of the millstone by introducing a constant temperature circulating liquid medium, which is a conventional circulating cooling liquid and has a temperature of 0 to 4 ℃.
In this context, the process of cyclic milling in step (2) is actually carried out by milling the material through a millstone-shaped mechanochemical reactor, collecting the product at the discharge end, and then placing the product in the millstone-shaped mechanochemical reactor again for milling treatment, wherein the process is regarded as cyclic milling for 1 time.
In this context, the polyolefin elastomer OBC described in step (3) is advantageous for further enhancing the mechanical properties of the triboelectrically regenerated product, as well as for improving the uniformity of the cell size during the foaming process. The polyolefin elastomer OBC is referred to as INFUSE TM The general trade name of the (dow chemical) OBC olefin block copolymer, one skilled in the art can select a suitable model according to the actual needs and process conditions, such as the OBC olefin block copolymer (OBC, 9100,12mol% ocene) used in the examples of the present application. Note that the polyolefin elastomer OBC may or may not be added, and experiments prove that the proper foaming temperature does not change significantly after the polyolefin elastomer OBC is added, which means that the foaming temperature does not change substantially on the premise of adding a small amount of filler/auxiliary agent.
In one embodiment, the components of the raw materials in step (3) may further include conventional fillers/adjuvants to further function expansion/process assistance/enhancement of the triboelectric regenerated product, and the specific filler/adjuvant selection thereof may be referred to by those skilled in the art according to the prior art or the prior literature, such as titanium dioxide, talc, graphite powder, etc. Note that the components of the raw materials described in step (3) may or may not include conventional fillers/adjuvants.
In another aspect, the present application provides a triboelectric recycled article prepared by the above-described method of preparation.
The triboelectric regenerated product can be used for triboelectric generators, express foam packages, automobile interiors and the like.
The application has the following beneficial effects:
1. the application is based on experiments, and the isotatic polypropylene waste can be milled and crushed by a solid-phase mechanochemical shearing technology, and then the product with excellent performance can be prepared by supercritical carbon dioxide foaming treatment.
2. The application has found by accident that in the actual supercritical carbon dioxide foaming treatment process operation, after the foaming temperature is obviously reduced, the triboelectric regenerated product with complete and uniform foam cells and excellent triboelectric performance is successfully prepared, which is obviously different from the traditional cognition of polypropylene foaming process conditions in the prior art.
3. The application has the advantages of simple process, easy operation, batch and continuous production, is suitable for recycling waste polypropylene packaging materials, and has good commercial value.
Drawings
FIG. 1 is a photograph showing the triboelectric regenerated products prepared in example 2, comparative example 1, comparative example 2, respectively, according to the present application. Wherein the left graph (a) is prepared in the condition of the foaming temperature of 150 ℃ in comparative example 2, the middle graph (b) is prepared in the condition of the foaming temperature of 145 ℃ in comparative example 1, the right graph (c) is prepared in the condition of the foaming temperature of 140 ℃ in example 2, and all the three are finished to prepare the sample under the pressure of 20MPa. It is evident that the surface of the article exhibited a significant amount of collapse at 150℃and 145℃foaming temperatures.
FIG. 2 is a cross-sectional electron micrograph of the triboelectric recycled article prepared in example 2, comparative example 1, comparative example 2, respectively. Wherein the left graph (a) is prepared in the condition of the foaming temperature of 150 ℃ in comparative example 2, the middle graph (b) is prepared in the condition of the foaming temperature of 145 ℃ in comparative example 1, the right graph (c) is prepared in the condition of the foaming temperature of 140 ℃ in example 2, and all the three are finished to prepare the sample under the pressure of 20MPa. It is evident that in the left graph (a) the polypropylene is substantially completely melt collapsed, the gas cannot be entrapped in the melt and thus cells cannot be formed, and as the foaming temperature is reduced to 145 ℃, a portion of the cells appear, but it is still evident that a portion of the melt is bonded and collapsed, whereas when the foaming temperature is reduced to 140 ℃, a uniform and complete cell structure is clearly observed.
FIG. 3 is a graph showing the triboelectric properties of the triboelectric regenerated products prepared in examples 1 to 2 and comparative examples 1 to 2 according to the present application. Wherein the left graph (a) is a triboelectric output voltage versus graph, and the right graph (b) is a triboelectric output current versus graph.
FIG. 4 is a photograph of a triboelectric regenerated article of the application as measured for triboelectric properties. Wherein the triboelectric performance test operation is as follows: firstly, fixing a test sample on a template, then starting a computer program to activate a linear motor to make the linear motor strike the sample back and forth at a certain speed, transmitting an electric signal appearing on the surface of the sample to an electrometer for collecting signals through a lead, and finally transmitting the electric signal back to a computer.
Detailed Description
For a further understanding of the present application, preferred embodiments of the application are described below in conjunction with the examples, but it should be understood that these descriptions are merely intended to illustrate further features and advantages of the application and are not limiting of the application claims. Those skilled in the art can, with the benefit of this disclosure, suitably modify the process parameters to achieve this. It is expressly noted that all such similar substitutions and modifications will be apparent to those skilled in the art, and are deemed to be included within the present application. While the methods and applications of this application have been described in terms of preferred embodiments, it will be apparent to those skilled in the relevant art that variations and modifications can be made in the methods and applications described herein, and in the practice and application of the techniques of this application, without departing from the spirit or scope of the application. While the following terms are believed to be well understood by those of ordinary skill in the art, the following definitions are set forth to aid in the description of the presently disclosed subject matter.
In one aspect, the application provides a method for preparing a triboelectric recycled product based on waste polypropylene, which mainly comprises the following steps:
(1) The recycled polypropylene waste is used as reclaimed materials for standby after pretreatment including cleaning; wherein the polypropylene waste is composed mainly of isotactic polypropylene (iPP);
(2) Adding the reclaimed materials into a grinding disc-shaped solid-phase mechanochemical reactor for grinding and crushing, and collecting the polypropylene ultrafine powder after grinding is completed; wherein, the technological parameters of the millstone-shaped solid phase mechanochemical reactor are as follows: the milling pressure is 1-10 MPa, the cyclic milling is 1-10 times, and the rotating speed of the millstone is 10-50 revolutions per minute;
(3) The raw materials mainly comprising the following components in parts by weight are mixed and prepared to be used as a mixture:
80 to 100 parts of polypropylene ultrafine powder,
0 to 20 parts of polyolefin elastomer OBC,
wherein the total of the polypropylene ultrafine powder and the polyolefin elastomer OBC is 100 parts;
(4) Mixing and granulating the mixture prepared in the step (3) through a double-screw extruder to obtain composite granules; wherein the technological parameters of the twin-screw extruder are as follows: the temperature from the feed inlet to the die is 160-200 ℃, the temperature interval of each section of screw is not more than 20 ℃, and the screw rotating speed is 50-80 r/min;
(5) Preparing the composite granules obtained in the step (4) into a composite material through a flat vulcanizing machine; wherein the technological parameters of the flat vulcanizing machine are as follows: the pressure is 6-10 Mpa, the upper plate temperature is 180-200 ℃, the lower plate temperature is 180-200 ℃, the hot pressing is carried out for 4-7 min, and the cold pressing is carried out for 3-5 min;
(6) Foaming the composite material obtained in the step (5) through supercritical carbon dioxide to prepare a triboelectric regenerated product; wherein the technological parameters of the supercritical carbon dioxide foaming treatment are as follows: the foaming temperature is 130-140 ℃, and the foaming pressure is 15-25 MPa.
The main object of the present application is to find out the problem of high-value recycling of polypropylene waste by a single accidental search conducted by the present inventors. Heretofore, the applicant of the present application has found that it can promote the processability of polymers for the technical purpose of reprocessing and reusing based on the solid phase shear milling technology for the polymer milling pulverization, and filed and published a series of patents and papers (for example CN1341677 a), but the regenerated products obtained by such technical solutions are generally low-end products, and cannot realize the high-value recycling of polymer waste.
Based on the current situation, the inventor of the application based on the conventional grinding and crushing of the polypropylene ultrafine powder by a millstone-shaped solid-phase mechanochemical reactor, occasionally found that in the process of supercritical carbon dioxide foaming treatment, when foaming is carried out according to the supercritical carbon dioxide foaming process parameters conventionally applicable to the polypropylene material, the obtained regenerated product has serious cell collapse phenomenon, so that the normal regenerated foam product cannot be prepared. For this situation, it will be generally determined by those skilled in the art that since polypropylene is derived from polypropylene waste, the processability of polypropylene is very limited after processing and use without adding other additives/fillers, and although the processability can be improved to some extent based on the solid phase shear milling technique, there is a certain upper limit to the effect, so that it is expected that normal recycled foam products cannot be prepared under the conventional foaming process conditions.
However, the inventor of the application discovered accidentally in one exploration attempt that after the foaming temperature is further remarkably reduced, a regenerated product with normal foaming morphology is prepared, and tested, the regenerated product has better triboelectric performance, the triboelectric performance is further improved along with the reduction of the foaming temperature, and the regenerated product can be directly applied to a triboelectric generator, so that the high-value recycling of polypropylene waste is realized.
It is important to note that in the prior art, the conventionally applicable supercritical carbon dioxide foaming temperature of the polypropylene material is generally considered to be 155 ℃ -170 ℃ (Zhang Zhuang, xu Zhixin, zheng Anna, etc.), the influence of the process temperature on the cell structure of the supercritical CO2 foamed polypropylene [ J ]. The university of Huadong university of technology: natural science edition, 2010,36 (5): 7.), and when the temperature is lower than 155 ℃ and even lower than 140 ℃, the melting of the polymer is insufficient, so that a polypropylene product with normal foaming morphology cannot be obtained, and even the product has a situation that the part does not have the cell morphology due to insufficient foaming. The principle of the polypropylene waste (mainly comprising isotactic polypropylene) used in the application is not known at present, and presumably the polypropylene waste is caused by other impurities contained in the polypropylene waste, because the applicable foaming temperature is changed to 130-140 ℃ after the polypropylene waste is ground and crushed by a millstone-shaped solid-phase mechanochemical reactor.
With reference to the technical scheme provided by the application, the triboelectric regenerated product with good cell morphology is successfully prepared at the foaming temperature of 130-140 ℃, the maximum output voltage of the triboelectric regenerated product can reach 85V, a commercial capacitor with the maximum output voltage of 1 mu F is charged to 6.8V in 100S, and about 60 LED small bulbs can be lightened.
The polypropylene waste in the step (1) is mainly made of isotactic polypropylene (iPP), and may be waste products or corner reclaimed materials made of isotactic polypropylene (iPP), and in one embodiment, the polypropylene waste may be a commodity transparent packaging film, particularly preferably a cigarette transparent packaging film, or may be food packaging materials or waste made of polypropylene; waste products or scrap recovery having an isotactic polypropylene ratio of not less than 95wt% may also be selected.
In one embodiment, the pretreatment in step (1) includes cleaning, which mainly eliminates impurities other than polypropylene and, if necessary, removes portions other than polypropylene, and the person skilled in the art can perform specific treatment according to the prior art according to the actual condition of the product or recycled material that needs to be recycled. In a preferred embodiment, the pretreatment further comprises treating the polypropylene powder or polypropylene crumb suitable for being placed into a pan-shaped solid-phase mechanochemical reactor for grinding and crushing, and the skilled artisan is aware of the fact that the device utilizes the principle of grinding and crushing with a high shear grinding pan through the mechanochemical reactor disclosed in the applicant's prior issued patent ZL 95111258.9, and thus generally optionally crushing the polypropylene powder or polypropylene crumb to polypropylene particles having a mean particle diameter of not more than 5mm, such as by conventional prior art crushing equipment such as high-speed impact crushers, jaw crushers, cryoball mills, and the like; or when the polypropylene waste in the form of film is treated into plastic film strips with the length of not more than 1-5 cm.
In this context, the millstone-shaped solid phase mechanochemical reactor in step (2) is a mechanochemical reactor disclosed in a patent ZL 95111258.9 previously issued by the applicant of the present application, wherein the millstone-shaped solid phase mechanochemical reactor further comprises other conventional process parameters, and the method for preparing polymer ultrafine powder by using the millstone-shaped solid phase mechanochemical reactor disclosed in a patent CN1341677a previously issued by the applicant of the present application can be further referred to, wherein in one embodiment, the process parameters of the millstone-shaped solid phase mechanochemical reactor further comprise controlling the temperature of the millstone by introducing a constant temperature circulating liquid medium into the millstone, wherein the liquid medium is a conventional circulating cooling liquid and has a temperature of 0 to 4 ℃.
In this context, the process of cyclic milling in step (2) is actually carried out by milling the material through a millstone-shaped mechanochemical reactor, collecting the product at the discharge end, and then placing the product in the millstone-shaped mechanochemical reactor again for milling treatment, wherein the process is regarded as cyclic milling for 1 time.
In one embodiment, the process parameters of the millstone-shaped solid phase mechanochemical reactor in step (2) are: the milling pressure is 1-10 MPa, such as 1MPa, 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa, 10MPa or any range or point value between them; cycling the milling 1-10 times, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; the rotation speed of the grinding disc is 10-50 rpm, such as 10 rpm, 15 rpm, 20 rpm, 25 rpm, 30 rpm, 35 rpm, 40 rpm, 45 rpm, 50 rpm or any range or point value therebetween.
In this context, the polyolefin elastomer OBC described in step (3) contributes to further enhancing the mechanical properties of the triboelectrically regenerated product, and to improving the foamingUniformity of cell size during processing. The polyolefin elastomer OBC is referred to as INFUSE TM The general trade name of the (dow chemical) OBC olefin block copolymer, in one embodiment the polyolefin elastomer OBC is an OBC olefin block copolymer (OBC, 9100,12mol% ocene), which can be selected by one skilled in the art to suit the actual needs and process conditions. Note that the polyolefin elastomer OBC may or may not be added, and experiments prove that the proper foaming temperature does not change significantly after the polyolefin elastomer OBC is added, which means that the foaming temperature does not change substantially on the premise of adding a small amount of filler/auxiliary agent.
In one embodiment, the polyolefin elastomer OBC in step (3) is 0 to 20 parts, wherein 0 part means no polyolefin elastomer OBC is added and non-0 part means polyolefin elastomer OBC is added, such as 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, or any range or point value therebetween.
In one embodiment, the components of the raw materials in step (3) may further include conventional fillers/adjuvants to achieve further functional expansion/process assistance/enhancement of the triboelectric recycled product, the specific filler/adjuvant selection of which may be referred to by those skilled in the art in light of the prior art or the prior literature, such as titanium dioxide, talc, graphite powder, etc. Note that the components of the raw materials described in step (3) may or may not include conventional fillers/adjuvants.
In one embodiment, the process parameters of the twin screw extruder of step (4) are: the temperature from the feed inlet to the die is 160-200 ℃, the temperature interval of each section of screw rod is not more than 20 ℃, and the rotation speed of the screw rod is 50-80 r/min, such as 50r/min, 55r/min, 60r/min, 65r/min, 70r/min, 75r/min, 80r/min or any range or point value between the two.
In one embodiment, the process parameters of the press vulcanizer in step (5) are: the pressure is 6-10 Mpa, such as 6Mpa, 7Mpa, 8Mpa, 9Mpa, 10Mpa or any range or point value between them; the upper plate temperature is 180-200 ℃, such as 180 ℃, 185 ℃, 190 ℃, 195 ℃, 200 ℃ or any range or point value between the two; the lower plate temperature is 180-200 ℃, such as 180 ℃, 185 ℃, 190 ℃, 195 ℃, 200 ℃ or any range or point value between the lower plate temperature and the lower plate temperature; hot pressing for 4 to 7 minutes, for example, 4 minutes, 5 minutes, 6 minutes, 7 minutes, or any range or point value therebetween; cold pressing for 3 to 5 minutes, for example 3 minutes, 4 minutes, 5 minutes or any range or point value therebetween.
In one embodiment, the process parameters of the supercritical carbon dioxide foaming process in step (6) are as follows: the foaming temperature is 130 to 140 ℃, such as 130 ℃, 131 ℃, 132 ℃, 133 ℃, 134 ℃, 135 ℃, 136 ℃, 137 ℃, 138 ℃, 139 ℃, 140 ℃ or any range or point value between them; the foaming pressure is 15 to 25MPa, for example 15MPa, 16MPa, 17MPa, 18MPa, 19MPa, 20MPa, 21MPa, 22MPa, 23MPa, 24MPa, 25MPa or any range or point value therebetween.
In another aspect, the present application provides a triboelectric recycled article prepared by the above-described method of preparation.
The triboelectric regenerated product can be used for triboelectric generators, commodity foam packages, automobile interiors and the like.
The present application will be explained in further detail with reference to examples. However, those skilled in the art will appreciate that these examples are provided for illustrative purposes only and are not intended to limit the present application.
Examples
Embodiments of the present application will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only for illustrating the present application and should not be construed as limiting the scope of the present application. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention. The application should not be construed as being limited to the particular embodiments described.
1. Raw materials
Waste polypropylene reclaimed material
Polyolefin elastomer OBC (INFUSE TM OBC,9100,12mol％octene)
2. Preparation method
(1) The recycled polypropylene waste is used as reclaimed materials for standby after pretreatment including cleaning; wherein the polypropylene waste is composed mainly of isotactic polypropylene (iPP);
(2) Adding the reclaimed materials into a grinding disc-shaped solid-phase mechanochemical reactor for grinding and crushing, and collecting the polypropylene ultrafine powder after grinding is completed; wherein, the technological parameters of the millstone-shaped solid phase mechanochemical reactor are as follows: the milling pressure is 8MPa, the milling is circularly carried out for 5 times, and the rotating speed of the millstone is 50 revolutions per minute;
(3) The raw materials mainly comprising the following components in parts by weight are mixed and prepared to be used as a mixture:
80 to 100 parts of polypropylene ultrafine powder,
0 to 20 parts of polyolefin elastomer OBC,
wherein the total of the polypropylene ultrafine powder and the polyolefin elastomer OBC is 100 parts;
(4) Mixing and granulating the mixture prepared in the step (3) through a double-screw extruder to obtain composite granules; wherein the technological parameters of the twin-screw extruder are as follows: 160 ℃ of a charging port, 165 ℃ of a first area, 175 ℃ of a second area, 170 ℃ of a third area, 165 ℃ of a die, and 70r/min of screw rotation speed;
(5) Preparing the composite granules obtained in the step (4) into a composite material through a flat vulcanizing machine; wherein the technological parameters of the flat vulcanizing machine are as follows: the pressure is 8Mpa, the upper plate temperature is 185 ℃, the lower plate temperature is 180 ℃, the hot pressing is carried out for 6min, and the cold pressing is carried out for 5min;
(6) Foaming the composite material obtained in the step (5) through supercritical carbon dioxide to prepare a triboelectric regenerated product; wherein the technological parameters of the supercritical carbon dioxide foaming treatment are as follows: the foaming temperature is 130-140 ℃, and the foaming pressure is 20MPa.
3. Test method
Scanning electron microscope test: the morphology and fracture of the foamed article were observed using a Scanning Electron Microscope (SEM) (FEI instrument, usa). The test sample was sprayed with gold prior to testing.
Triboelectric testing: the foamed article was subjected to periodic impact tests by a linear motor (HS 01-37,166, NTI AG, U.S.A.), and open circuit voltage (Voc) and short circuit current (Isc) were collected on a Keithley 6514 system electrometer and SR570 low noise current amplifier, respectively.
Example 1, comparative examples 1 to 2
Examples 1 and comparative examples 1 to 2 were prepared according to the above preparation method, wherein the composition of the mixture was PP/OBC (85/15), and the foaming temperature was compared as a variable, as shown in Table 1 below:
it is apparent from Table 1 above that when the foaming temperature is more than 140 ℃, the cell structure of the regenerated product exhibits a remarkable defect of cohesive collapse, and cannot be used as a regenerated product, and the triboelectric properties thereof are also severely degraded. And correspondingly, when the foaming temperature is 130-140 ℃, the foam cell structure of the regenerated product is uniform and complete, and when the foaming temperature reaches 135 ℃, the triboelectric performance of the regenerated product is optimal, and the temperature is obviously lower than the foaming temperature of conventional polypropylene and is obviously different from the conventional recognition of polypropylene-based materials applied to supercritical carbon dioxide foaming by a person skilled in the art.
Examples 2 to 5 were prepared according to the above preparation method, in which the foaming products were each at 140℃and the ratio of PP to OBC was compared as a variable, as shown in Table 2 below:
it is clear from table 2 above that the addition of the polyolefin elastomer OBC is advantageous in improving the uniformity of cells of the regenerated article, but the most preferable addition thereof is that too much addition of OBC results in a decrease in triboelectric properties thereof, which is difficult to find by observing the morphology of cells only by electron microscopy.
The foregoing examples are illustrative of the present application and are not intended to be limiting, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principles of the application are intended to be equivalent and are within the scope of the present application.
Claims (5)
1. The preparation method of the triboelectric regenerated product based on the waste polypropylene is characterized by mainly comprising the following steps of:
(1) The recycled polypropylene waste is used as reclaimed materials for standby after pretreatment including cleaning; wherein the polypropylene waste is composed mainly of isotactic polypropylene;
(2) Adding the reclaimed materials into a grinding disc-shaped solid-phase mechanochemical reactor for grinding and crushing, and collecting the polypropylene ultrafine powder after grinding is completed; wherein, the technological parameters of the millstone-shaped solid phase mechanochemical reactor are as follows: the milling pressure is 1-10 MPa, the cyclic milling is 1-10 times, and the rotating speed of the millstone is 10-50 revolutions per minute;
(3) The raw materials mainly comprising the following components in parts by weight are mixed and prepared to be used as a mixture:
80 to 100 parts of polypropylene ultrafine powder,
0 to 20 parts of polyolefin elastomer OBC,
wherein the total of the polypropylene ultrafine powder and the polyolefin elastomer OBC is 100 parts;
(4) Mixing and granulating the mixture prepared in the step (3) through a double-screw extruder to obtain composite granules; wherein the technological parameters of the twin-screw extruder are as follows: the temperature from the feed inlet to the die is 160-200 ℃, the temperature interval of each section of screw is not more than 20 ℃, and the screw rotating speed is 50-80 r/min;
(5) Preparing the composite granules obtained in the step (4) into a composite material through a flat vulcanizing machine; wherein the technological parameters of the flat vulcanizing machine are as follows: the pressure is 6-10 Mpa, the upper plate temperature is 180-200 ℃, the lower plate temperature is 180-200 ℃, the hot pressing is carried out for 4-7 min, and the cold pressing is carried out for 3-5 min;
(6) Foaming the composite material obtained in the step (5) through supercritical carbon dioxide to prepare a triboelectric regenerated product; wherein the technological parameters of the supercritical carbon dioxide foaming treatment are as follows: the foaming temperature is 130-140 ℃, and the foaming pressure is 15-25 MPa.
2. The method of manufacture of claim 1, wherein: the polyolefin elastomer OBC in the step (3) is 15 parts.
3. The method of manufacture of claim 1, wherein: the foaming temperature in the process parameters of the supercritical carbon dioxide foaming treatment in the step (6) is 135 ℃.
4. The triboelectric regenerated article according to claim 1 which is produced by the process for producing a waste polypropylene-based triboelectric regenerated article.
5. The triboelectric recycling product according to claim 4, wherein the product is used in the fields of triboelectric generators, commodity foam packaging and automotive interiors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211642787.2A CN116120621B (en) | 2022-12-20 | 2022-12-20 | Triboelectric regenerated product based on waste polypropylene and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211642787.2A CN116120621B (en) | 2022-12-20 | 2022-12-20 | Triboelectric regenerated product based on waste polypropylene and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116120621A CN116120621A (en) | 2023-05-16 |
| CN116120621B true CN116120621B (en) | 2023-10-13 |
Family
ID=86303684
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211642787.2A Active CN116120621B (en) | 2022-12-20 | 2022-12-20 | Triboelectric regenerated product based on waste polypropylene and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116120621B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002167460A (en) * | 2000-09-20 | 2002-06-11 | Jsp Corp | Production method of polypropylene based resin foaming particle, polypropylene based resin foaming particle and polypropylene based resin inner foaming molded product |
| JP2006116818A (en) * | 2004-10-21 | 2006-05-11 | Kaneka Corp | Method for producing foamed polyolefin resin molding using waste foamed polyolefin resin molding and its molding |
| CN101538387A (en) * | 2008-03-17 | 2009-09-23 | 中国科学院宁波材料技术与工程研究所 | Polypropylene foaming material and production method thereof |
| CN104476711A (en) * | 2014-12-18 | 2015-04-01 | 江苏微赛新材料科技有限公司 | Method for producing uniform thick polypropylene micropore foaming plate |
| CN106543559A (en) * | 2016-10-17 | 2017-03-29 | 广东聚石化学股份有限公司 | A kind of preparation method of expanded polypropylene beads |
| CN113427732A (en) * | 2021-06-29 | 2021-09-24 | 四川大学 | Method for inducing formation of Shish-kebab precursor in polypropylene random copolymer by using waste IPP (interpenetrating polymer network) material |
| CN113563630A (en) * | 2021-08-11 | 2021-10-29 | 江苏中科聚合新材料产业技术研究院有限公司 | Preparation method and application of durable hydrophilic polypropylene foaming particles |
| CN115044134A (en) * | 2022-07-11 | 2022-09-13 | 北京工商大学 | High-strength high-resilience polypropylene foam, preparation method thereof and method for controlling resilience and compression strength of polypropylene foam |
-
2022
- 2022-12-20 CN CN202211642787.2A patent/CN116120621B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002167460A (en) * | 2000-09-20 | 2002-06-11 | Jsp Corp | Production method of polypropylene based resin foaming particle, polypropylene based resin foaming particle and polypropylene based resin inner foaming molded product |
| JP2006116818A (en) * | 2004-10-21 | 2006-05-11 | Kaneka Corp | Method for producing foamed polyolefin resin molding using waste foamed polyolefin resin molding and its molding |
| CN101538387A (en) * | 2008-03-17 | 2009-09-23 | 中国科学院宁波材料技术与工程研究所 | Polypropylene foaming material and production method thereof |
| CN104476711A (en) * | 2014-12-18 | 2015-04-01 | 江苏微赛新材料科技有限公司 | Method for producing uniform thick polypropylene micropore foaming plate |
| CN106543559A (en) * | 2016-10-17 | 2017-03-29 | 广东聚石化学股份有限公司 | A kind of preparation method of expanded polypropylene beads |
| CN113427732A (en) * | 2021-06-29 | 2021-09-24 | 四川大学 | Method for inducing formation of Shish-kebab precursor in polypropylene random copolymer by using waste IPP (interpenetrating polymer network) material |
| CN113563630A (en) * | 2021-08-11 | 2021-10-29 | 江苏中科聚合新材料产业技术研究院有限公司 | Preparation method and application of durable hydrophilic polypropylene foaming particles |
| CN115044134A (en) * | 2022-07-11 | 2022-09-13 | 北京工商大学 | High-strength high-resilience polypropylene foam, preparation method thereof and method for controlling resilience and compression strength of polypropylene foam |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116120621A (en) | 2023-05-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103030882B (en) | It is a kind of to be used to prepare regrown material of bumper and preparation method thereof | |
| CN108148281B (en) | Low-odor regenerated polypropylene composite material for automobile interior and exterior decoration and preparation method thereof | |
| US6555588B2 (en) | Method for the production of a polypropylene blend | |
| CN102382406B (en) | Polyvinyl butyral foamed material | |
| US9138969B2 (en) | Insulation sheets prepared from unseparated mixtures of post-consumer plastic articles | |
| KR102181876B1 (en) | Manufacturing method of composite resin composition using waste separator for secondary battery | |
| CN103756124A (en) | Polypropylene foaming material, production and preparation method of product | |
| US20140024778A1 (en) | Toughened comingled post-consumer thermoplastics and method for recycling thermoplastic waste | |
| CN102167877B (en) | Chain-extended regenerated polypropylene material and preparation method thereof | |
| US20230398726A1 (en) | Method for preparing composite resin composition by using secondary battery waste separators | |
| CN113650193B (en) | Method for recycling multi-component mixed plastic waste | |
| CN116120621B (en) | Triboelectric regenerated product based on waste polypropylene and preparation method thereof | |
| MX2013011207A (en) | Method for treating technical textiles. | |
| US5476628A (en) | GMT sheet material produced from GMT recyclate | |
| CN112140407A (en) | Method for recycling waste TPO skin material | |
| CN114907600B (en) | Single and double direction solid phase stretching processing method for regenerated mixed plastic material | |
| KR101688089B1 (en) | Resin composition for tray comprising the pellet powder manufactured using polyethylene separated from milk carton paper and the tray manufactured using the same | |
| CN114106441A (en) | Method for preparing regenerated product by using waste phosphogypsum and waste crosslinked polyethylene | |
| JP5535744B2 (en) | Method for producing resin composition | |
| JP2022532538A (en) | Manufacturing method and additive composition of additives for bitumen conglomerate with high mechanical performance | |
| JP5774075B2 (en) | Method for producing resin composition | |
| CN114479226B (en) | Antistatic polyethylene composition, polyethylene molded body and preparation method of antistatic polyethylene composition | |
| CN115464818B (en) | Method for preparing composite regenerated plastic product by using waste leather material | |
| Prut et al. | Structure and properties of rubber powder and its materials | |
| JPH11320561A (en) | Method for recycling resin material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |