CN111849055B - Polyethylene resin composition, polyethylene resin pellet, polyethylene expanded bead, method for producing same, and molded article - Google Patents

Polyethylene resin composition, polyethylene resin pellet, polyethylene expanded bead, method for producing same, and molded article Download PDF

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CN111849055B
CN111849055B CN201910340230.5A CN201910340230A CN111849055B CN 111849055 B CN111849055 B CN 111849055B CN 201910340230 A CN201910340230 A CN 201910340230A CN 111849055 B CN111849055 B CN 111849055B
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polyethylene
weight
maleic anhydride
composition
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CN111849055A (en
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郭鹏
徐耀辉
吕明福
解娜
张师军
徐萌
高达利
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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    • 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
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • 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
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/08—Copolymers of ethene
    • 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
    • C08J2435/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least one other carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/10—Esters; Ether-esters
    • C08K5/101—Esters; Ether-esters of monocarboxylic acids
    • C08K5/103—Esters; Ether-esters of monocarboxylic acids with polyalcohols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/13—Phenols; Phenolates
    • C08K5/134—Phenols containing ester groups
    • C08K5/1345—Carboxylic esters of phenolcarboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/49—Phosphorus-containing compounds
    • C08K5/51—Phosphorus bound to oxygen
    • C08K5/52—Phosphorus bound to oxygen only
    • C08K5/524—Esters of phosphorous acids, e.g. of H3PO3
    • C08K5/526—Esters of phosphorous acids, e.g. of H3PO3 with hydroxyaryl compounds

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
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  • Polymers & Plastics (AREA)
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Abstract

The present invention relates to the field of expanded polyethylene, and specifically relates to a polyethylene resin composition, a method for producing polyethylene resin pellets, polyethylene expanded beads, and a molded article thereof. The composition comprises 100 parts by weight of polyethylene base resin, 0.1-0.3 part by weight of antioxidant and 0.25-10 parts by weight of mixed olefin-maleic anhydride copolymerized microspheres, wherein the particle size of the mixed olefin-maleic anhydride copolymerized microspheres is 0.05-2 mu m. The foaming bead prepared from the composition disclosed by the invention by the method disclosed by the invention has a more compact and uniform cell structure, uniform pore size, complete appearance without fracture and lower density. In addition, the foaming bead is in a non-crosslinking structure, so that the foaming bead can be recycled, secondary pollution is avoided, and the requirement of circular economy is met. The formed product made of the expanded bead has higher compression strength and better thermal oxidation aging resistance.

Description

Polyethylene resin composition, polyethylene resin pellet, polyethylene expanded bead, method for producing same, and molded article
Technical Field
The present invention relates to the field of expanded polyethylene, and specifically relates to a polyethylene resin composition, polyethylene resin pellets, polyethylene expanded beads, a method for producing the same, and a molded article of polyethylene expanded beads.
Background
Nowadays, polyethylene foamed products are generally produced industrially on a large scale by using extrusion foaming technology.
Compared with the traditional extrusion foaming method, when the polyethylene foaming product is prepared by the reaction kettle dipping method, the screw extrusion high-shear action of the extrusion method acting on the polyethylene melt can not occur, and the entanglement of the polymer chain ensures that the melt has enough strength. In the process of cell growth, the bidirectional stretching of the cell wall is not easy to break; meanwhile, PE crystals are not completely melted in the foaming process, and the residual crystals play a role of physical cross-linking points, so that the foamed polyethylene (EPE) with high foaming ratio and high closed cell ratio is more easily realized. Thus, in the reaction kettle dipping method, the polyethylene does not need to be modified by adding peroxide or a cross-linking agent, and the original melt strength can meet the foaming requirement. Compared with crosslinked foamed polyethylene, the foamed polyethylene obtained by the reaction kettle impregnation method has no crosslinked structure, can be recycled, and has small side effect on the environment. In addition, the bead product can be molded to obtain products with various shapes, thereby greatly expanding the application field of the polyethylene foaming material. The EPE expanded beads obtained by the reaction kettle dipping method have a plurality of melting peaks, wherein the low-temperature peak is beneficial to reducing the required steam pressure and temperature in the subsequent compression molding process, thereby reducing the energy consumption of equipment.
Compared with polypropylene foaming bead forming body, the heat-resistant temperature of polyethylene is lower, and matrix resin needs to be modified to improve the heat-resistant performance of polyethylene without influencing the mechanical property and the forming effect of polyethylene.
Disclosure of Invention
The invention aims to solve the problems of complicated process and the like of a batch type polyethylene expanded bead production process in the prior art, and provides a polyethylene resin composition, polyethylene resin granules, polyethylene expanded beads, a preparation method thereof and a polyethylene expanded bead molded body.
In order to achieve the above object, the first aspect of the present invention provides a polyethylene resin composition comprising 100 parts by weight of a polyethylene base resin, 0.1 to 0.3 part by weight of an antioxidant, and 0.25 to 10 parts by weight of mixed olefin-maleic anhydride copolymerized microspheres, wherein the mixed olefin-maleic anhydride copolymerized microspheres have a particle size of 0.05 to 2 μm.
The present invention provides, in a second aspect, a process for producing polyethylene resin pellets, the process comprising:
(1) mixing the composition of the first aspect of the invention in a blender to obtain a blend;
(2) adding the blend into an extruder for extrusion and granulation;
preferably, in step (2), the extrusion temperature is 180-.
In a third aspect, the present invention provides expanded beads of polyethylene prepared from the composition according to the first aspect of the present invention.
The fourth aspect of the present invention provides a method for preparing polyethylene expanded beads, which comprises: granulating and cutting the composition of the first aspect of the present invention, and foaming the resulting polyethylene resin particles;
preferably, the foaming method is a reaction kettle dipping foaming method.
The fifth aspect of the present invention provides a polyethylene expanded bead molded body obtained by molding the polyethylene expanded bead according to the third aspect of the present invention and/or the polyethylene expanded bead obtained by the method according to the fourth aspect of the present invention.
Through the technical scheme, the invention provides the polyethylene resin composition containing the polyethylene base resin, the antioxidant and the mixed olefin-maleic anhydride copolymerized microspheres serving as the foam cell nucleating agent, and the polyethylene foamed beads with the chemical composition containing maleic anhydride structural units can be further prepared. In addition, the foaming bead is in a non-crosslinking structure, so that the foaming bead can be recycled, secondary pollution is avoided, and the requirement of circular economy is met. The molded body prepared from the expanded bead has higher compression strength and better thermal-oxidative aging resistance.
Drawings
FIG. 1 is a photograph showing a cross section of expanded beads described in example 15.
FIG. 2 is a photograph of a cross section of the expanded beads of comparative example 11.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The first aspect of the present invention provides a polyethylene resin composition comprising 100 parts by weight of a polyethylene base resin, 0.1 to 0.3 part by weight of an antioxidant, and 0.25 to 10 parts by weight of a mixed olefin-maleic anhydride copolymerized microsphere; wherein the particle size of the mixed olefin-maleic anhydride copolymerized microsphere is 0.05-2 μm.
Preferably, the composition comprises 100 parts by weight of polyethylene base resin, 0.1-0.3 part by weight of antioxidant and 0.25-4 parts by weight of mixed olefin-maleic anhydride copolymerized microspheres; wherein the particle size of the mixed olefin-maleic anhydride copolymerized microsphere is 0.2-2 μm.
In this context, the term "particle size" is understood to mean the average diameter.
According to the composition, preferably, the content of the maleic anhydride structural unit in the mixed olefin-maleic anhydride copolymerized microsphere is 48 to 55 mol%.
According to the composition, preferably, the mixed olefin-maleic anhydride copolymerized microspheres are copolymers prepared by copolymerizing carbon four and maleic anhydride in the presence of nitrogen, an initiator and an organic solvent. The organic solvent is any reaction solvent known in the art, preferably at least one of isoamyl acetate, butyl acetate, isopropyl acetate, and ethyl acetate. The initiator may be any initiator known in the art, preferably dibenzoyl peroxide or azobisisobutyronitrile.
In the present invention, the mixed C4 can come from various petroleum processing and refining processes and can be C4A mixture of hydrocarbon compounds. Preferably, the mixed carbon four contains at least one of 1-butene, isobutene, 1, 3-butadiene, n-butane, isobutane, cis-2-butene and trans-2-butene, and may be, for example, liquefied fuel produced in a petroleum refining process, cracked gas produced by cracking naphtha, gas produced by producing olefins from methanol, and the like. The composition of the mixed C.sub.D can be analyzed by gas chromatography using Agilent's 7890A Gas Chromatograph (GC).
Preferably, the compositional content of the mixed C.sub.D can be 1-99 wt% of 1-butene, 1-99 wt% of isobutylene, 0-99 wt% of 1, 3-butadiene, 0-50 wt% of 1, 2-butadiene, 0-99 wt% of n-butane, 1-99 wt% of isobutane, 5-20 wt% of vinyl acetylene, 0-99 wt% of cis-2-butene, and 1-99 wt% of trans-2-butene.
According to a preferred embodiment of the present invention, the composition content of the mixed C.sub.D may be 5-10 wt% of 1-butene, 5-15 wt% of isobutene, 10-20 wt% of 1, 3-butadiene, 5-15 wt% of 1, 2-butadiene, 0.5-5 wt% of n-butane, 0.5-2 wt% of isobutane, 20-40 wt% of cis-2-butene, 2-10 wt% of trans-2-butene, 5-20 wt% of vinyl acetylene.
According to another preferred embodiment of the present invention, the composition content of the mixed C.sub.D may be 0.1-2 wt% of 1-butene, 10-30 wt% of isobutene, 0.01-0.1 wt% of 1, 3-butadiene, 0.5-5 wt% of n-butane, 30-40 wt% of isobutane, 20-40 wt% of cis-2-butene, 5-20 wt% of trans-2-butene.
According to another preferred embodiment of the present invention, the compositional content of mixed C.sub.D may be 5-15 wt% of 1-butene, 0.5-3 wt% of isobutene, 20-30 wt% of n-butane, 15-30 wt% of cis-2-butene, 35-45 wt% of trans-2-butene.
In the present invention, 1-butene, 2-butene, isobutylene and 1, 3-butadiene in the mixed C4 are copolymerized with maleic anhydride. During the copolymerization reaction, the weight ratio of the mixed C4 to the maleic anhydride is preferably (0.2-3): 1; preferably (0.8-3): 1.
more preferably, the initiator is used in an amount of 0.05 to 20 mole% based on the maleic anhydride.
During the copolymerization reaction, preferably, the conditions of the copolymerization reaction include: the temperature is 50-100 ℃, and the optimal temperature is 70-90 ℃; the pressure is 0.2-2MPa, preferably 0.5-1MPa, and the copolymerization reaction time is 5-10 h.
In the invention, a certain amount of mixed C4 is introduced into a reaction kettle filled with a certain amount of maleic anhydride, an initiator and an organic solvent to carry out copolymerization reaction under the conditions of nitrogen atmosphere and the copolymerization reaction, and then the reaction product is centrifugally separated to obtain the mixed olefin-maleic anhydride copolymerized microsphere. Wherein, the mixed C4, the maleic anhydride, the initiator and the organic solvent are used in the same amount as described above. The obtained microspheres can be further washed by hexane and filtered by a sand core to obtain a filter cake, and the filter cake is dried in vacuum at the temperature of between 80 and 100 ℃ for about 6 to 10 hours to obtain a product which can be analyzed for the content of the components and used for the polypropylene modified composition.
More preferably, the mixed olefin-maleic anhydride copolymerized microspheres are alternating copolymer microspheres and the content of maleic anhydride structural units is about 50 mol%.
According to the invention, the polyethylene base resin contains component a, component B and component C; the component A is linear low density polyethylene copolymerized by ethylene-alpha olefin, and the melt index of the component A is measured at 190 ℃ and under the load of 2.16kgMIAIs 0.01-2g/10min, the density rho of the component AA0.880-0.936g/cm3(ii) a The component B is linear low density polyethylene copolymerized by ethylene-alpha olefin, and the melt index MI of the component B is measured at 190 ℃ and under the load of 2.16kgBIs 2.1-14.9g/10min, the density rho of the component BBIs 0.910 to 0.930g/cm3(ii) a The component C is linear low density polyethylene copolymerized by ethylene-alpha olefin, and the melt index MI of the component C is measured at 190 ℃ and under the load of 2.16kgCIs 15-150g/10min, the density rho of the component CCIs 0.880-0.930g/cm3。
In a preferred embodiment of the composition according to the invention, the component A has a melt index MI at a temperature of 190 ℃ and a load of 2.16kgAFrom 0.01 to 1.5g/10min, the melt index MI of the component B at a temperature of 190 ℃ and a load of 2.16kgBIs 3 to 10g/10min, the component C has a melt index MI at a temperature of 190 ℃ and a load of 2.16kgCIs 15-100g/10 min.
More preferably, the component A has a melt index MI at a temperature of 190 ℃ and a load of 2.16kgAFrom 0.01 to 1g/10min, the melt index MI of the component B at a temperature of 190 ℃ and under a load of 2.16kgBIs 3 to 5g/10min, the component C has a melt index MI at a temperature of 190 ℃ and a load of 2.16kgCIs 20-60g/10 min.
In the present invention, the melt index is measured by the method defined in GB/T3682-2000.
Preferably, the density ρ of the component AAIs 0.910 to 0.930g/cm3Density p of said component BBIs 0.913-0.928g/cm3Density p of said component CCIs 0.905-0.928g/cm3。
More preferably, the density ρ of the component AAIs 0.915-0.926g/cm3Density p of said component BBIs 0.913-0.924g/cm3Density p of said component CCIs 0.910 to 0.926g/cm3。
Further preferably, the density ρ of the component A, the component B and the component CA、ρBAnd ρCThe relationship between them satisfies-0.04 ≤ rhoA-ρBRho is not less than 0.02 and not more than-0.04A-ρCLess than or equal to 0.02. This enables the polyethylene base resin to have better foaming properties, and the polyethylene expanded beads made of the composition composed of the polyethylene base resin have a more dense and uniform cell structure, and the molded articles made of the polyethylene expanded beads have higher compressive strength.
Here, the linear structure of the component a, the component B and the component C means that the molecular chain contains only a short-chain structure, but does not contain a long-chain structure and a cross-linked structure, and the linear structure is determined by a polymerization monomer and polymerization process conditions, is well known to those skilled in the art, and is not described herein again.
According to the present invention, in order to obtain a polyethylene base resin having better foaming properties, it is preferable that the weight part W of the component a in the polyethylene base resinA25 to 90 weight portions of the component B, the weight portion W of the component BB0.1 to 10 parts by weight of the component C, the mass part of the component C, WC10-75 parts by weight; more preferably, in the polyethylene base resin, the mass part W of the component AA30-80 parts by weight of the component B, WB0.5 to 8 weight portions of the component C, the weight portion W of the component CC20 to 70 weight portions.
Further preferably, the mass fraction W of the component AAComponent C, part by mass WCMelt index MI with component AASatisfies 5.2 XlgMIA+11.6≥WA/WC≥0.9×lgMIA+2.1, more preferably 2.9 XlgMIA+6.8≥WA/WC≥1.1×lgMIA+2.7. This enables the polyethylene base resin to have a better foaming property, and the polyethylene expanded beads made of the composition composed of the polyethylene base resin have a more dense and uniform cell structure, and the resulting molded articles of the polyethylene expanded beads have a higher compressive strength.
According to the invention, the polyethylene base resin has a melt index of 0.1 to 20g/10min, preferably 0.5 to 10g/10min, at a temperature of 190 ℃ and under a load of 2.16 kg. When the component a, the component B and the component C having the specific melt index and density are used in combination, the melt index of the polyethylene base resin as a whole is controlled within the above range, and the resulting polyethylene composition can have very excellent foaming properties.
According to the invention, the molecular weight distribution indexes of the component A, the component B and the component C all satisfy Mw/Mn4.5 or less, preferably 2.0 or less Mw/MnLess than or equal to 4.2. In order to obtain component A, component B and component C having the above molecular weight distribution, it is preferable that the component A, component B and component C are polymerized using a metallocene catalyst. The kind of the metallocene catalyst can be selected conventionally in the art, and it generally consists of a metallocene compound and an organoaluminum compound, and optionally an electron donor, and is known to those skilled in the art, and is not described herein.
After intensive research, the inventors of the present invention found that when a component a, a component B and a component C having the above-mentioned melt index and density, which are obtained by polymerization using a metallocene catalyst, are used in combination, a composition composed of the polyethylene base resin has good foaming properties when expanded beads are prepared by a reaction tank impregnation method and the obtained expanded beads have a good cell structure, and a molded body obtained from the obtained expanded beads also has very high compressive strength, and is very suitable for home and automobile materials.
According to the present invention, the content of the copolymerized units of the alpha olefin in the component a, the component B and the component C is not particularly limited, and for example, the copolymerized units of the alpha olefin in the component a, the component B and the component C may each independently be contained in an amount of 0.2 to 15 mol%, preferably 1.5 to 10 mol%. In the present invention, the molar content of the copolymerized units of the alpha olefin means a ratio of the molar amount of the structural units formed by polymerization of the alpha olefin to the molar amount of the total monomer structural units. In addition, the alpha-olefins in component A, component B and component C are each independently selected from C3-C20At least one of olefins. The component A, the component B and the component are from the viewpoint of easy availability of raw materialsThe alpha olefin in C is preferably at least one selected from the group consisting of propylene, 1-butene, 2-butene, 3-methyl-1-butene, 4-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3-dimethyl-1-pentene, 3, 4-dimethyl-1-pentene, 4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene, 1-heptene, 2-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene, more preferably at least one selected from the group consisting of 1-butene, 1-hexene and 1-octene.
According to the composition of the present invention, the antioxidant may be any oxidizing agent known in the art, preferably at least one selected from hindered phenolic antioxidants, phosphite antioxidants, thioester antioxidants. The hindered phenol antioxidant can be monophenol, bisphenol and polyphenol; the phosphite antioxidant comprises alkyl phosphite and aryl phosphite; the sulfofat antioxidant comprises a sulfofat antioxidant, a sulfophenol antioxidant and a sulfobisphenol antioxidant. In one embodiment, the antioxidant may also be a complex antioxidant, for example, a complex of at least two of hindered phenol antioxidants, phosphite antioxidants, and thioester antioxidants in a certain mass ratio. For example, the antioxidant is preferably a complex antioxidant consisting of a hindered phenol antioxidant 1010 and a phosphite antioxidant 168 in a weight ratio of 1: 1.
The composition according to the present invention may further comprise other adjuvants, such as at least one of slip agents, antistatic agents, lubricants, plasticizers, and the like, which do not adversely affect the properties of the polyethylene. In addition, the amount of the other auxiliary agents is selected conventionally in the field, and can be known by those skilled in the art.
In a preferred embodiment of the composition of the present invention, the composition further comprises a glyceryl monostearate of the formula: c21H42O4. The substance can help to improve the dispersibility of the mixed olefin-maleic anhydride copolymerized microspheres in the polyethylene base resin. Preferably the glycerol monostearate is added in an amount of mixed olefin-maleic acid1-10% of anhydride copolymerization microsphere.
The present invention provides, in a second aspect, a process for producing polyethylene resin pellets, the process comprising:
(1) mixing the composition of the first aspect of the invention in a blender to obtain a blend;
(2) adding the blend into an extruder for extrusion and granulation;
preferably, in step (2), the extrusion temperature is 180-.
In the process for producing polyethylene resin pellets according to the present invention, in step (1), preferably, the composition according to the present invention is mixed in a high-speed mixer. More preferably, in the composition, the mixed olefin-maleic anhydride copolymer microspheres are added in an amount of 0.25 to 10 parts by weight, the antioxidant is added in an amount of 0.1 to 0.3 parts by weight, and the glycerol monostearyl ester is added in an amount of 1 to 10% by weight, relative to 100 parts by weight of the polyethylene base resin.
In the method for preparing polyethylene resin pellets according to the present invention, preferably, in the step (2), the extrusion temperature is 195-210 ℃.
In a third aspect, the present invention provides expanded beads of polyethylene prepared from the composition according to the first aspect of the present invention. The density of the expanded beads is less than 0.6g/cm3. The polyethylene foamed bead has compact pores, uniform pore diameter, complete appearance and no fracture. The average pore diameter is 30-300 μm and the sphericity of the beads can reach 85% according to the adjustment of the foaming process.
The fourth aspect of the present invention provides a method for preparing polyethylene expanded beads, which comprises: granulating and cutting the composition, and foaming the obtained polyethylene resin particles;
preferably, the foaming method is a reaction kettle dipping foaming method.
In the method for preparing polyethylene expanded beads according to the present invention, the granulation may be performed in various manners known in the art, for example, the polyethylene resin composition may be extruded into strands through one or more dies of a twin-screw or single-screw extruder and cut to obtain polyethylene resin particles, or an underwater microparticle pelletizing system may be used, and the specific operation process is well known to those skilled in the art.
According to one embodiment of the process for the preparation of expanded beads of polyethylene according to the present invention, the granulation comprises the following steps:
1) adding the polyethylene resin composition, optional antioxidant and other additives (such as antistatic agent) into a high-speed mixer according to a certain proportion, and uniformly mixing;
2) extruding the mixture obtained in step 1) through a twin-screw extruder, hot-cutting, introducing into water at 75 ℃ or lower, preferably 70 ℃ or lower, more preferably 55-65 ℃ to perform microparticle cutting so that the length/diameter ratio of each particle is 0.5-2.0, preferably 0.8-1.3, more preferably 0.9-1.1, and the average weight is 0.1-20mg, preferably 0.2-10mg, more preferably 1-3 mg. The length/diameter ratio as described herein is an average of 200 randomly selected polyethylene composition particles.
In the method for preparing polyethylene expanded beads according to the present invention, the foaming may be performed in various conventional manners, for example, by an extrusion foaming method, or by a reaction vessel immersion foaming method, preferably by a reaction vessel immersion foaming method, and the expanded beads obtained by the reaction vessel immersion foaming method have a non-crosslinked structure, can be recycled, do not cause secondary pollution, and meet the requirements of recycling economy.
More preferably, the reaction kettle dip foaming process comprises the steps of:
(a) mixing polyethylene resin particles with a dispersion medium, a surfactant, a dispersant and a dispersion enhancer in an autoclave,
(b) covering the autoclave tightly, discharging the residual air in the autoclave by using an air discharging method, namely using a foaming agent, then continuously adding the foaming agent into the autoclave, starting heating and primarily adjusting the pressure until the foaming agent is stable, then stirring the autoclave at a stirring speed of 50-150rmp, preferably 90-110rmp, and heating the autoclave at a constant speed to a temperature which is 0.1-5 ℃, preferably 0.5-1 ℃ lower than the expansion stability;
(c) adjusting the pressure in the autoclave to the pressure required for foaming, the pressure being 1-10MPa, preferably 3-5MPa, raising the temperature to the foaming temperature at an average heating rate of 0.1 ℃/min, the foaming temperature being 0.1-5 ℃, preferably 0.5-1 ℃ lower than the melting temperature of the microparticles, and continuously stirring for 0.1-2h, preferably 0.25-0.5h under the conditions of the foaming temperature and the foaming pressure;
(d) the discharge port of the autoclave was opened to discharge the contents of the autoclave into a collection tank to obtain polyethylene expanded beads, and carbon dioxide gas was fed while discharging the contents so that the pressure in the autoclave was maintained at about the foaming pressure before all the particles were completely foamed and entered the collection tank.
In this context, unless otherwise specified, the pressures are gauge pressures.
Herein, the "expansion temperature" refers to a temperature required for the polypropylene resin fine particles in order to obtain a polypropylene expanded bead having a target expansion ratio, and the "expansion pressure" refers to a saturation pressure of the blowing agent required in order to obtain a polypropylene expanded bead having a target expansion ratio.
In this context, unless otherwise specified, the pressures are gauge pressures.
In the foaming process of the present invention, the dispersion medium may be any of various dispersion media capable of dispersing the polyethylene resin fine particles therein without dissolving the components thereof, and for example, may be at least one of water, ethylene glycol, glycerin, methanol, ethanol, and the like, and water is particularly preferable. Further, the amount of the dispersion medium may be 1000-.
The surfactant may be any of various conventional components capable of promoting dispersion of the polyethylene resin microparticles in the dispersion medium, and may be at least one of stearic acid, sodium dodecylbenzenesulfonate, quaternary ammonium compounds, lecithin, amino acids, betaine, fatty acid glycerides, sorbitan fatty acids, polysorbates, and the like, and sodium dodecylbenzenesulfonate is particularly preferable. Further, the surfactant is preferably used in an amount of 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, and more preferably 0.1 to 0.5 parts by weight, relative to 100 parts by weight of the polyethylene resin fine particles.
The purpose of the dispersant is to prevent the polyethylene resin particles from melt-bonding to each other during foaming. The dispersant may be an organic dispersant or an inorganic dispersant, and is preferably an inorganic dispersant. In order to more effectively prevent the polyethylene resin microparticles from being melt-bonded to each other during foaming, the inorganic dispersant is preferably at least one of natural or synthetic clay minerals (e.g., kaolin, mica, magnesium aluminum garnet, clay, etc.), alumina, titanium dioxide, basic magnesium carbonate, basic zinc carbonate, calcium carbonate, silica, zinc borate, iron oxide, etc., and particularly preferably kaolin. Further, the dispersant is preferably used in an amount of 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the polyethylene resin fine particles.
The purpose of the addition of the dispersion enhancer is to improve the dispersion efficiency of the dispersant, i.e., to reduce the amount of the dispersant while retaining its function of preventing melt-bonding between particles. The dispersion enhancer may be any of various existing inorganic compounds having a solubility of 1mg in 100mL of water at 40 ℃ and providing a divalent anion or a trivalent anion or cation. Examples of the dispersion-enhancing agent include, but are not limited to, at least one of magnesium nitride, magnesium nitrate, aluminum phosphate, magnesium sulfate, aluminum nitride, aluminum nitrate, aluminum sulfate, ferric chloride, ferric sulfate, ferric nitrate, and the like, preferably aluminum sulfate. In order to obtain polyethylene expanded beads having an apparent density of 100g/L or more, the dispersion-reinforcing agent is preferably used in an amount of 0.0001 to 1 part by weight, preferably 0.01 to 0.2 part by weight, based on 100 parts by weight of the polyethylene resin fine particles.
It is also often necessary to add a blowing agent during the foaming process. The foaming agent can be an organic physical foaming agent or an inorganic physical foaming agent. Among them, examples of the organic type physical blowing agent include, but are not limited to, at least one of aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane, alicyclic hydrocarbons such as cyclobutane and cyclohexane, and halogenated hydrocarbons such as chlorofluoromethane, trifluoromethane, 1, 2-difluoroethane, 1,2,2, 2-tetrafluoroethane, methyl chloride, ethyl chloride, methylene chloride, and the like. Examples of the inorganic type physical blowing agent include, but are not limited to, at least one of air, nitrogen, carbon dioxide, oxygen, and water. In order to maintain the stability (uniformity) of the apparent density of the polyethylene expanded beads while considering low cost and environmental friendliness, the blowing agent is preferably carbon dioxide and/or nitrogen, and particularly preferably carbon dioxide. In addition, the amount of the blowing agent to be used may be determined depending on the specific kind of the blowing agent, the foaming temperature, and the apparent density of the polyethylene expanded beads to be produced. For example, when nitrogen is used as the blowing agent and water is used as the dispersion medium, the pressure in the closed vessel (i.e., the pressure (gauge pressure) in the upper space in the closed vessel) at the time of depressurization in the foaming apparatus is controlled to 1 to 12 MPa; when carbon dioxide is used as the blowing agent, the gauge pressure is controlled to 1 to 7 MPa. Generally, the desired pressure in the upper space within the closed vessel increases as the apparent density of the polyethylene expanded beads is expected to decrease.
The foaming bead has a more compact and uniform cell structure, uniform pore diameter, complete appearance without fracture, lower density and density lower than 2g/cm3. In addition, the foaming bead is in a non-crosslinking structure, so that the foaming bead can be recycled, secondary pollution is avoided, and the requirement of circular economy is met.
The fifth aspect of the present invention provides a polyethylene expanded bead molded body obtained by molding the polyethylene expanded bead according to the third aspect of the present invention and/or the polyethylene expanded bead produced by the method according to the fourth aspect of the present invention. The molded body prepared from the expanded bead has higher compression strength and more excellent thermo-oxidative aging resistance.
According to the present invention, the molding can be performed in various existing molding machines, and the molding conditions can be selected conventionally in the art, and it can be known to those skilled in the art, and will not be described herein again.
The present invention will be described in detail below by way of examples.
In the following examples and comparative examples, the relevant data were obtained according to the following test methods:
(1) melt index MI: the measurement is carried out according to the method specified in GB/T3682-2000, wherein the test temperature is 190 ℃, and the load is 2.16 kg;
(2) density of polyethylene and composition: measuring by a density gradient column method according to a method specified in GB/T1033.2-2010; the density of the expanded polyethylene beads was measured according to ASTM D792.
(3) Compression strength test of molded articles: cutting a sample of 50X 25mm from the foamed bead molded body, performing a compression strength test based on American ASTM standard D3575-08, and performing a compression test at a compression rate of 10mm/min to obtain a compression strength at which the molded body is compressed by 50%;
(4) testing the heat distortion temperature according to ISO-75 standard;
(5) the oxidative induction period is measured according to ISO11357-6 at a test temperature of 200 ℃.
The raw materials used in the preparation examples and examples are as follows:
the mixed C-C A comprises the following components in percentage by weight: 1, 2-butadiene, 8.92%; 1, 3-butadiene, 14.14%; 1-butene, 8.38%; trans-2-butene, 5.84%; cis-2-butene, 31.7%; vinyl acetylene, 10.99%; isobutane, 1.3%; isobutene, 12.78%; n-butane 2.58%, others, 3.37%.
The mixed C-B comprises the following components in percentage by weight: 1, 3-butadiene, 0.06%; trans-2-butene, 12.67%; isobutane, 37.09%; 19.48 percent of isobutene; cis-2-butene, 27.79%; 1-butene, 1.02%; others, 1.89%.
The mixed C-C comprises the following components in percentage by weight: trans-2-butene, 40.83%; cis-2-butene, 18.18%; 24.29 percent of n-butane; 1-butene, 9.52%; isobutene, 2.78%; others, 4.4%.
Glycerol monostearyl ester was purchased from Heda, ATMER 129V.
Preparation example 1
The polyethylene base resin of this preparation example contained component a, component B, component C and a lubricant. Wherein, the component A, the component B and the component C are all Linear Low Density Polyethylene (LLDPE) copolymerized by ethylene-alpha olefin, and are all prepared by adopting the same catalyst system (metallocene catalyst) and polymerization process, and the difference is that the amount of hydrogen added and the types and molar contents of alpha-olefin comonomers are different when different components are prepared. The method comprises the following specific steps:
ethylene, alpha-olefin, hydrogen and nitrogen (all of which are polymerization stages and used after water and oxygen removal, the same applies hereinafter) were added to a fluidized bed gas phase reactor, and then a metallocene catalyst system (the metallocene catalyst system is a supported metallocene catalyst prepared by CN102453124A example 1, the same applies hereinafter) was added, and then polymerization was carried out at a temperature of 84 to 88 ℃ and a pressure of 1.8 to 2MPa, to obtain a component a, a component B and a component C, respectively. Wherein, the control of the melt indexes of the component A, the component B and the component C is realized by adjusting the adding amount of hydrogen, and the control of the density is realized by adjusting the type and the adding amount of alpha olefin. The alpha olefin used in the process for preparing component A is 1-hexene, the alpha olefin used in the process for preparing component B is 1-hexene, and the alpha olefin used in the process for preparing component C is 1-butene.
Through detection, the properties of the component A, the component B and the component C prepared by the method are as follows:
melt index MI of component AA1.5g/10min, density ρA＝0.913g/cm3Molecular weight distribution index Mw/Mn3.4, the molar content of alpha olefin comonomer is 7.5 mol%;
melt index MI of component BB2.1g/10min, density ρB＝0.913g/cm3Molecular weight distribution index Mw/Mn3.2, the molar content of alpha olefin comonomer is 7.5 mol%;
melt index MI of component CC15g/10min, density ρC＝0.905g/cm3Molecular weight distribution index Mw/MnThe molar content of the alpha olefin comonomer was 9.1 mol%, 3.5.
The lubricant was a PEG lubricant manufactured by Switzerland, and the number average molecular weight was 10000.
Weighing and mixing the component A, the component B and the component C according to the proportion, wherein the component A is W in part by massA80 parts by weight of the component B, WB10 parts by weight of component C, WCIs 20 parts by weight, WA/WC4 (satisfy 5.2 × lgMI)A+11.6≥WA/WC≥0.9×lgMIA+2.1, also satisfies 2.9 XlgMIA+6.8≥WA/WC≥1.1×lgMIA+ 2.7); then adding a lubricant (the adding amount of the lubricant is 0.1 part by weight calculated by the total weight of the component A, the component B and the component C being 100 parts by weight), then adding the mixture into a high-speed stirrer for uniform mixing, then adding the mixed material into a feeder of a double-screw extruder manufactured by Nanjing Kekuron company, feeding the material into a double screw through the feeder, keeping the temperature of the screw between 180 ℃ and 240 ℃ in the processing process, melting and uniformly mixing through the screw, then extruding, granulating and drying to obtain polyethylene base resin granules (PE101), and detecting the melt index MI of the polyethylene base resin granules to be 2.4g/10 min.
Preparation example 2
The polyethylene base resin of this example contained component a, component B, component C and a lubricant. Wherein, the component A, the component B and the component C are all Linear Low Density Polyethylene (LLDPE) copolymerized by ethylene-alpha olefin, and are all prepared by adopting the same catalyst system (metallocene catalyst) and polymerization process, and the difference is that the components are obtained by different amounts of hydrogen added and the types and molar contents of alpha-olefin comonomers when different components are prepared. The method comprises the following specific steps:
adding ethylene, alpha olefin, hydrogen and nitrogen into a fluidized bed gas phase reactor, then adding a metallocene catalyst system, and then polymerizing under the conditions that the temperature is 84-88 ℃ and the pressure is 1.8-2MPa to respectively obtain a component A, a component B and a component C. Wherein, the control of the melt indexes of the component A, the component B and the component C is realized by adjusting the adding amount of hydrogen, and the control of the density is realized by adjusting the type and the adding amount of alpha olefin. The alpha olefin used in the process for preparing component A is 1-butene, the alpha olefin used in the process for preparing component B is 1-butene, and the alpha olefin used in the process for preparing component C is 1-hexene.
Through detection, the properties of the component A, the component B and the component C prepared by the method are as follows:
melt index MI of component AA0.01g/10min, density ρA＝0.930g/cm3Molecular weight distribution index Mw/Mn3.0, the molar content of alpha olefin comonomer is 1.6 mol%;
melt index MI of component BBDensity p of 10.0g/10minB＝0.930g/cm3Molecular weight distribution index Mw/Mn2.8, the molar content of alpha olefin comonomer is 1.9 mol%;
melt index MI of component CC60g/10min, density ρC＝0.922g/cm3Molecular weight distribution index Mw/MnThe molar content of the alpha olefin comonomer was 3.8 mol%, 2.9.
Weighing and mixing the component A, the component B and the component C according to the proportion, wherein the component A is W in part by massAIs 55 parts by weight, the mass part W of the component BBIs 5 parts by weight, the mass part W of the component CCIs 55 parts by weight, WA/WC1 (satisfies 5.2 XlgMI)A+11.6≥WA/WC≥0.9×lgMIA+2.1, also satisfies 2.9 XlgMIA+6.8≥WA/WC≥1.1×lgMIA+ 2.7); then adding a lubricant (the adding amount of the lubricant is 0.1 part by weight calculated by the total weight of the component A, the component B and the component C being 100 parts by weight), then adding the mixture into a high-speed stirrer for uniform mixing, then adding the mixed material into a feeder of a double-screw extruder manufactured by Nanjing Kekuron company, feeding the material into a double screw through the feeder, keeping the temperature of the screw between 180 ℃ and 240 ℃ in the processing process, melting and uniformly mixing through the screw, then extruding, granulating and drying to obtain polyethylene base resin granules (PE102), and detecting the melt index MI of the polyethylene base resin granules to be 0.9g/10 min.
Preparation example 3
The polyethylene base resin of the preparation example is obtained by polymerizing a multi-reactor parallel device, wherein a component A is prepared by polymerizing a first reactor 1, a component B is prepared by polymerizing a second reactor 2, and a component C is prepared by polymerizing a third reactor 3, the three components are all Linear Low Density Polyethylene (LLDPE) copolymerized by ethylene-alpha olefin, wherein the three components are prepared by adopting the same catalyst system (metallocene catalyst) and polymerization process, and the difference is that the amount of hydrogen added when different components are prepared, the type and the molar content of alpha olefin comonomer and the unit time yield of each reactor are different. The method comprises the following specific steps:
adding alpha olefin, n-hexane and hydrogen into a polymerization reactor, heating the polymerization reactor to a preset polymerization temperature, simultaneously adding an ethylene monomer and a catalyst system into the polymerization reactor, and polymerizing for 30 minutes under the conditions that the temperature is 140 ℃ and the pressure is 2.5MPa to respectively obtain a component A, a component B and a component C. Wherein, the control of the melt indexes of the component A, the component B and the component C is realized by adjusting the adding amount of hydrogen, and the control of the density is realized by adjusting the type and the adding amount of alpha olefin. The alpha olefin used in the preparation of component A is 1-octene, the alpha olefin used in the preparation of component B is 1-butene, and the alpha olefin used in the preparation of component C is 1-butene.
The production per unit time W of component A in the first reactor 1 during the preparationAThe yield per unit time W of component B in the second reactor 2BWith the yield per unit time W of component C in the third reactor 3CIs maintained at WA：WB：WC75: 2: 35 wherein WA/WC2.1 (satisfy 5.2 × lgMI)A+11.6≥WA/WC≥0.9×lgMIA+2.1, also satisfies 2.9 XlgMIA+6.8≥WA/WC≥1.1×lgMIA+2.7)。
Through detection, the properties of the component A, the component B and the component C prepared by the method are as follows:
melt index MI of component AADensity p of 0.1g/10minA＝0.92g/cm3Molecular weight distribution index Mw/Mn3.1, the molar content of alpha olefin comonomer is 2.1 mol%;
melt index MI of component BBDensity ρ of 5.0g/10minB＝0.92g/cm3Molecular weight distribution index Mw/Mn3.5, the molar content of alpha olefin comonomer is 5.1 mol%;
melt index MI of component CC25g/10min, density ρC＝0.92g/cm3Molecular weight distribution index Mw/MnThe molar content of the alpha olefin comonomer was 5.1 mol%, 3.2.
The lubricant was a PEG lubricant manufactured by Switzerland, and the number average molecular weight was 10000.
The component A, the component B and the component C are respectively conveyed into different solid/liquid (gas) separators 4 according to the yield ratio per unit time for phase separation and then conveyed into a homogenizing silo 5 with stirring, and then the lubricant is added according to the proportion for mixing and homogenizing. Wherein the lubricant is added in an amount of 0.1 part by weight based on 100 parts by weight of the total of the above-mentioned component A, component B and component C. And then adding the mixture homogenized by the homogenizing silo 5 into a feeder of a double-screw extruder manufactured by Nanjing Keplong company, feeding the materials into the double screws through the feeder, keeping the temperature of the screws between 160 ℃ and 210 ℃ in the processing process, melting and uniformly mixing the materials by the screws, extruding, granulating and drying to obtain polyethylene base resin granules (PE103), and detecting the melt index MI of the polyethylene base resin granules to be 0.6g/10 min.
Examples 1 to 6, optimization examples 1 to 3
(1) Preparation of copolymerized microspheres
Under the protection of nitrogen, 14kg of mixed C-IV A is introduced into a 200L reaction kettle containing 20kg of organic reaction liquid of maleic anhydride, 2.4kg of azodiisobutyronitrile and 100L of isoamyl acetate for copolymerization reaction, the copolymerization reaction pressure is 0.9MPa, the copolymerization reaction temperature is 70 ℃, and the copolymerization reaction time is 6 h;
and introducing the copolymerization reaction product into a flash separator for gas-liquid separation at 25 ℃ and 0MPa, continuously performing liquid-solid separation on the obtained liquid-solid mixture in a centrifugal separator at 4000rpm for 20min to obtain a solid product, washing with hexane, and performing vacuum drying on a filter cake obtained by suction filtration of a sand core funnel for 8h at 90 ℃ to obtain copolymer powder. The copolymer powder was tested, wherein the content of maleic anhydride structural units was 48 mol%; the average particle diameter was 0.2. mu.m.
(2) Preparation of polyethylene compositions
According to the components and the dosage of the polyethylene composition listed in the table 1, the mixed olefin-maleic anhydride copolymerized microspheres, the antioxidant and the glycerol monostearyl ester are put into a dry powder machine to be stirred to obtain uniformly mixed powder; adding PE101 and the powder into a high-speed mixer according to the proportion shown in the table 1, and mixing to obtain a mixture; adding the mixture into a double-screw extruder, performing melt extrusion granulation at the extrusion temperature of 195-210 ℃, and drying to obtain polyethylene resin granules A1-A6 and Y1-Y3.
Polyethylene resin pellets were taken for oxidative induction period, density and melt index testing. And then, carrying out injection molding on the polyethylene resin granules through an injection molding machine to obtain a test sample strip, and carrying out thermal deformation test on the test sample strip. The test results are shown in Table 1.
Examples 7 to 10, optimization examples 4 to 5
(1) Preparation of copolymerized microspheres
Under the protection of nitrogen, 13.5kg of mixed C-IV B is introduced into a 200L reaction kettle containing 20kg of maleic anhydride, 4kg of dibenzoyl peroxide and 100L of organic reaction liquid of isoamyl acetate for copolymerization reaction, the copolymerization reaction pressure is 1MPa, the copolymerization reaction temperature is 80 ℃, and the copolymerization reaction time is 6 h;
and introducing the copolymerization reaction product into a flash separator for gas-liquid separation at 30 ℃ and 0MPa, continuously performing liquid-solid separation on the obtained liquid-solid mixture in a centrifugal separator at 4000rpm for 20min to obtain a solid product, washing with hexane, and performing vacuum drying on a filter cake obtained by suction filtration of a sand core funnel for 8h at 90 ℃ to obtain copolymer powder. The copolymer powder was subjected to a test in which the content of maleic anhydride structural units was 51 mol%; the average particle diameter was 1 μm.
(2) Preparation of polyethylene compositions
According to the components and the dosage of the polyethylene composition listed in the table 1, the mixed olefin-maleic anhydride copolymerized microspheres, the antioxidant and the glycerol monostearyl ester are put into a dry powder machine to be stirred to obtain uniformly mixed powder; adding PE102 and the powder into a high-speed mixer according to the proportion shown in the table 1, and mixing to obtain a mixture; adding the mixture into a double-screw extruder, performing melt extrusion granulation at the extrusion temperature of 195-210 ℃, and drying to obtain polyethylene resin granules A7-A10 and Y4-Y5.
Polyethylene resin pellets were taken for oxidative induction period, density and melt index testing. And then, carrying out injection molding on the polyethylene resin granules through an injection molding machine to obtain a test sample strip, and carrying out thermal deformation test on the test sample strip. The test results are shown in Table 1.
Examples 11 to 14, optimization examples 6 to 7
(1) Preparation of copolymerized microspheres
Introducing 15kg of mixed C-C into a 200L reaction kettle containing 20kg of maleic anhydride, 4.5kg of dibenzoyl peroxide and 100L of isoamyl acetate to carry out copolymerization reaction at the copolymerization reaction pressure of 1.5MPa and the copolymerization reaction temperature of 90 ℃ for 10 h;
and introducing the copolymerization reaction product into a flash separator for gas-liquid separation at the temperature of 27 ℃ and under the pressure of 0MPa, continuously performing liquid-solid separation on the obtained liquid-solid mixture in a centrifugal separator at 8000rpm for 20min to obtain a solid product, washing with hexane, and performing vacuum drying on a filter cake obtained by suction filtration of a sand core funnel for 8h at the temperature of 90 ℃ to obtain copolymer powder. The copolymer powder was subjected to a test in which the content of maleic anhydride structural units was 55 mol%; the average particle diameter was 2 μm.
(2) Preparation of polyethylene compositions
Mixing the mixed olefin-maleic anhydride copolymerized microspheres, an antioxidant (hindered phenol antioxidant 1010: phosphite antioxidant 168: 1 (weight ratio)), and glycerol monostearyl ester according to a formula shown in table 1, and stirring by using a dry powder machine to obtain uniformly mixed powder; adding the mixed powder and polyethylene base resin (PE103) into a high-speed mixer according to the proportion shown in the table 1 for mixing; the mixed materials are put into a double-screw extruder and extruded and pelletized at the temperature of 195-210 ℃ to obtain polyethylene resin pellets A11-A14 and Y6-Y7. In addition, a part of the pellets was injection-molded by an injection molding machine to obtain heat-deformed specimens, and the data of the property test are shown in Table 1.
Comparative example 1
Polyethylene (PE101) and an antioxidant (hindered phenol antioxidant 1010: phosphite antioxidant 168: 1 (weight ratio)) are added into a high-speed mixer according to the proportion shown in the table 1, uniformly mixed, added into a double-screw extruder, extruded and granulated at 195-210 ℃, and dried to obtain granules D1. In addition, a part of the pellets was injection-molded by an injection molding machine to obtain heat-deformed specimens, and the data of the property test are shown in Table 1.
Comparative example 2
Polyethylene (PE102) and an antioxidant (hindered phenol antioxidant 1010: phosphite antioxidant 168: 1 (weight ratio)) are added into a high-speed mixer according to the proportion shown in the table 1, uniformly mixed, added into a double-screw extruder, extruded and granulated at 195-210 ℃, and dried to obtain granules D2. In addition, a part of the pellets was injection-molded by an injection molding machine to obtain heat-deformed specimens, and the data of the property test are shown in Table 1.
Comparative example 3
Polyethylene (PE103) and an antioxidant (hindered phenol antioxidant 1010: phosphite antioxidant 168: 1 (weight ratio)) are added into a high-speed mixer according to the proportion shown in Table 1, uniformly mixed, added into a double-screw extruder, extruded and granulated at 195-210 ℃, and dried to obtain granules D3. In addition, a part of the pellets was injection-molded by an injection molding machine to obtain heat-deformed specimens, and the data of the property test are shown in Table 1.
Comparative example 4
Polyethylene (PE101), an antioxidant (hindered phenol antioxidant 1010: phosphite antioxidant 168: 1 (weight ratio)), and 0.5 part by weight of a nucleating agent (talcum powder) are added into a high-speed mixer according to the proportion in the table 1, uniformly mixed, added into a double-screw extruder, extruded and granulated at 195-210 ℃, and dried to obtain granules D4. In addition, a part of the pellets was injection-molded by an injection molding machine to obtain heat-deformed specimens, and the data of the property test are shown in Table 1.
Comparative example 5
Polyethylene (PE102), an antioxidant (hindered phenol antioxidant 1010: phosphite antioxidant 168: 1 (weight ratio)), and 0.5 part by weight of a nucleating agent (silicon dioxide) are added into a high-speed mixer according to the proportion in Table 1, uniformly mixed, added into a double-screw extruder, extruded and granulated at 195-210 ℃, and dried to obtain granules D5. In addition, a part of the pellets was injection-molded by an injection molding machine to obtain heat-deformed specimens, and the data of the property test are shown in Table 1.
Comparative example 6
Polyethylene resin pellets were prepared as described in example 5, except that the base resin used was a general linear low density polyethylene (available from Tianjin, petrochemical corporation, China, trade name 7042), and the pellets D6 were obtained by mixing, extruding, granulating, and drying the components in the proportions described in example 5. In addition, a part of the pellets was injection-molded by an injection molding machine to obtain heat-deformed specimens, and the data of the property test are shown in Table 1.
TABLE 1
Figure BDA0002040471500000221
Figure BDA0002040471500000231
The antioxidant in Table 1 is a composite oxidant of antioxidant 1010 and antioxidant 168 in a weight ratio of 1: 1. The component amounts are all weight portions.
Examples 15 to 22, comparative examples 10 to 16
(1) 100 parts by weight of polyethylene resin pellets (prepared polyethylene resin pellets) and additives (antioxidant 1010:168 is 1:1) are placed into a high-speed stirrer to be mixed at a high speed for 30 seconds, then the mixture is added into a LabLine100 microparticle preparation system, the torque is controlled to be about 65 percent, the rotating speed is 300rpm, and the mixture is granulated under water to obtain polyethylene resin microparticles, wherein the length-diameter ratio of the polyethylene resin microparticles is 0.9-1.1, and the average weight is 1-3 mg.
(2) The specific foaming process is as follows: firstly, 100 parts by weight of polyethylene resin particles, 3000 parts by weight of dispersion medium (deionized water), 0.3 part by weight of surfactant (sodium dodecyl benzene sulfonate), 3 parts by weight of dispersant (kaolin) and 0.2 part by weight of dispersion reinforcing agent (aluminum sulfate) are added and mixed at one time in an autoclave;
(3) secondly, a blowing agent (CO) is used2Or nitrogen, see table 2) discharging residual air in the reaction kettle, removing the air in the reaction kettle, and tightly covering the kettle cover; feeding a blowing agent into the autoclave, initially adjusting the pressure until it is stable, and subsequently stirring the dispersion (water, preferably deionized water) in the autoclave, heating it to 0.5-1 ℃ below the expansion temperature with uniform heating;
(4) then, adjusting the pressure in the kettle to reach the pressure required by foaming; raising the temperature to a foaming temperature at an average heating rate of 0.1 ℃/minute, the foaming temperature being 0.5 to 1 ℃ below the melting temperature of the microparticles; continuously stirring for 0.25-0.5h under the conditions of foaming temperature and foaming pressure;
(5) finally, opening a discharge port of the high-pressure autoclave, and discharging materials in the reaction kettle into a collecting tank to obtain polyethylene expanded beads; carbon dioxide gas was fed while the discharge was being carried out so that the pressure in the autoclave was maintained near the foaming pressure before all the particles were fully foamed and entered the collection tank.
The density of the expanded beads obtained was measured according to ASTM D792, as shown in Table 2. Further, a part of the expanded beads was molded to obtain a polyethylene expanded bead molded body. The polyethylene expanded bead molded article was subjected to a performance test, and the results are shown in table 2.
TABLE 2
Figure BDA0002040471500000241
Figure BDA0002040471500000251
Note: the cell nucleating agent, for example "zinc borate/0.5" means that the cell nucleating agent is zinc borate and that the zinc borate is used in an amount of 0.5 parts by weight per 100 parts by weight of PE101, the other nucleating agents (silica, talc) being similar to the zinc borate in that they are used in such a way that the particle size of the zinc borate, talc, silica is 0.05 to 2 μm.
As can be seen from the above data shown in Table 2, the polyethylene expanded beads of the present invention are significantly lower in density, and the molded articles formed from the expanded beads are higher in compressive strength and better in resistance to thermal oxidative aging, as compared with comparative examples 10 to 16.
As shown in FIGS. 1 and 2, which are cross-sectional photographs of the expanded beads of example 15 and comparative example 11, it can be seen that the expanded beads obtained from the compositions of the present application (using copolymerized microspheres as cell nucleating agents) have good cell morphology, are dense and uniform, and do not crack.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (17)

1. A polyethylene resin composition comprises 100 parts by weight of polyethylene base resin, 0.1 to 0.3 part by weight of antioxidant and 0.25 to 10 parts by weight of mixed olefin-maleic anhydride copolymerized microspheres; the mixed olefin is from mixed C4;
the polyethylene base resin comprises a component A, a component B and a component C, wherein the component A is linear low density polyethylene copolymerized by ethylene-alpha olefin, and the melt index MI of the component A is measured at 190 ℃ and under the load of 2.16kgAIs 0.01-2g/10min, the density rho of the component AA0.880-0.936g/cm3(ii) a The component B is linear low density polyethylene copolymerized by ethylene-alpha olefin, and the melt index MI of the component B is measured at 190 ℃ and under the load of 2.16kgBIs 2.1-14.9g/10min, the density rho of the component BBIs 0.910 to 0.930g/cm3(ii) a The component C is linear low-density polyethylene copolymerized by ethylene-alpha olefin, and the component C is at 190 ℃ and 2Melt index MI measured under a load of 16kgCIs 15-150g/10min, the density rho of the component CCIs 0.880-0.930g/cm3；
Wherein the particle size of the mixed olefin-maleic anhydride copolymerized microsphere is 0.05-2 μm.
2. The composition of claim 1, wherein the mixed olefin-maleic anhydride copolymerized microspheres have a maleic anhydride structural unit content of 48 to 55 mol%.
3. The composition of claim 1 or 2, wherein the mixed olefin-maleic anhydride copolymerized microspheres are a copolymer prepared by copolymerizing mixed C4 and maleic anhydride in the presence of nitrogen, an initiator and an organic solvent.
4. The composition of claim 3, wherein the weight ratio of mixed C4 to maleic anhydride is (0.2-3): 1;
and/or the amount of the initiator is 0.05-30 mol% of the maleic anhydride;
and/or, the copolymerization reaction conditions include: the copolymerization reaction temperature is 50-100 ℃; the copolymerization pressure is 0.2-2 MPa; the copolymerization reaction time is 5-10 h.
5. The composition of claim 4, wherein the weight ratio of mixed C4 to maleic anhydride is (0.8-3): 1;
and/or the copolymerization reaction temperature is 70-90 ℃; the copolymerization pressure is 0.5-1 MPa.
6. Composition according to claim 1 or 2, wherein the density p of component aAIs 0.910 to 0.930g/cm3Density p of said component BBIs 0.913-0.928g/cm3Density p of said component CCIs 0.905-0.928g/cm3；
And/or the density ρ of the component A, the component B and the component CA、ρBAnd ρCThe relationship between them satisfies-0.04 ≤ rhoA-ρBRho is not less than 0.02 and not more than-0.04A-ρC≤0.02。
7. The composition according to claim 1, wherein the mass fraction W of component A in the polyethylene base resinA25 to 90 weight portions of the component B, the weight portion W of the component BB0.1 to 10 parts by weight of the component C, the mass part of the component C, WC10-75 parts by weight;
and/or the mass part W of the component AAComponent C, part by mass WCMelt index MI with component AASatisfies 5.2 XlgMIA+11.6≥WA/WC≥0.9×lgMIA+2.1。
8. The composition of claim 7, wherein the mass fraction W of component AA30-80 parts by weight of the component B, WB0.5 to 8 weight portions of the component C, the weight portion W of the component CC20-70 parts by weight;
and/or the mass part W of the component AAComponent C, part by mass WCMelt index MI with component AASatisfies 2.9 XlgMIA+6.8≥WA/WC≥1.1×lgMIA+2.7。
9. The composition according to any one of claims 1,2, 4, 5, 7 and 8, wherein the composition further comprises glycerol monostearate, and/or the glycerol monostearate is added in an amount of 1-10% by weight of the mixed olefin-maleic anhydride copolymerized microspheres.
10. The composition according to claim 3, wherein the composition further comprises glycerol monostearate, and/or the glycerol monostearate is added in an amount of 1-10% by weight of the mixed olefin-maleic anhydride copolymerized microspheres.
11. The composition according to claim 6, wherein the composition further comprises glycerol monostearate, and/or the glycerol monostearate is added in an amount of 1-10% by weight of the mixed olefin-maleic anhydride copolymerized microspheres.
12. A process for preparing polyethylene resin pellets, the process comprising:
(1) mixing the composition of any one of claims 1-11 in a blender to obtain a blend;
(2) and adding the blend into an extruder for extruding and granulating.
13. The method as claimed in claim 12, wherein, in the step (2), the extrusion temperature is 180-230 ℃.
14. Polyethylene expanded beads made from the composition of any of claims 1-11.
15. A method of preparing polyethylene expanded beads comprising: granulating and cutting the composition according to any one of claims 1 to 11, and foaming the resulting polyethylene resin particles.
16. The method of claim 15, wherein the foaming process is a kettle dip foaming process.
17. A polyethylene expanded bead molded article obtained by molding the polyethylene expanded bead according to claim 14 or the polyethylene expanded bead obtained by the method according to claim 15 or 16.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107312231A (en) * 2016-04-26 2017-11-03 中国石油化工股份有限公司 Polyethylene composition and expanded bead and preparation method thereof and expanded bead formed body
CN107501726A (en) * 2017-08-22 2017-12-22 芜湖蓝天工程塑胶有限公司 A kind of antibiotic polypropylene plastic and preparation method thereof
CN108623898A (en) * 2017-03-21 2018-10-09 石家庄欧强节能建材科技有限公司 The spacer bar of antimildew and antibacterial polypropylene material and preparation method with the application material

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107312231A (en) * 2016-04-26 2017-11-03 中国石油化工股份有限公司 Polyethylene composition and expanded bead and preparation method thereof and expanded bead formed body
CN108623898A (en) * 2017-03-21 2018-10-09 石家庄欧强节能建材科技有限公司 The spacer bar of antimildew and antibacterial polypropylene material and preparation method with the application material
CN107501726A (en) * 2017-08-22 2017-12-22 芜湖蓝天工程塑胶有限公司 A kind of antibiotic polypropylene plastic and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
《马来酸酐共聚微球的制备及应用》;贾红瑞;《化工管理》;20140531;全文 *

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