CN102816269B - High-melt-strength propylene/ethylene copolymer and preparation method thereof - Google Patents
High-melt-strength propylene/ethylene copolymer and preparation method thereof Download PDFInfo
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Abstract
The invention provides a method for preparing random high-melt-strength propylene/ethylene copolymer by direct polymerization. The method includes that during different serially operated polymerization reaction steps, according to requirements of different molecular grades, the propylene/ethylene copolymers with wide molecule distribution and 'overhigh molecular weight grade' can be prepared by controlling types and proportions of electron donor components in a Ziegler-Natta catalyst system in different reaction steps. The invention further provides random high-melt-strength propylene/ethylene copolymer which has great mechanical property, optical performance, in particular high impact strength, low melting point and high melt strength. Compared with homopolymer high-melt-strength polypropylene, the copolymerized high-melt-strength polypropylene is more applicable to preparation of multiplying-power foaming products and can be utilized in post processing for molding multiplying-power foaming beads with lower energy consumption, and the foaming beads are higher in cohesive strength and better in toughness.
Description
Technical field
The present invention relates to a kind of method with high melt strength, propylene of preparing, be specifically related to a kind of preparation method of propylene-ethylene random copolymer.The invention still further relates to a kind of propylene-ethylene random copolymer with high fondant-strength.
Technical background
The cutting out property of propylene polymer structures make its in injection moulding, extrude, obtain a wide range of applications in the manufacture field such as curtain coating, two-way stretch, but common polypropylene molecule has limited its application in fields such as thermoforming, foaming and blowings because melt strength is not high.Therefore, development has the polypropylene of high fondant-strength and good ductility, is the interested problems of people always.So-called high melt strength, propylene (HMSPP) just refers to that melt, under pulled out condition, can bear higher power when fracture.In the prior art, melt flow rate (MFR) MFR is the propene polymer of 2g/10min left and right, and its higher melt strength can reach 0.8-1N (newton).
The principal element that affects melt strength of polypropylene is the structure of polymer molecule, comprises the size of molecular weight, whether contains the length of long-chain branch and long-chain branch and distribute etc. on molecular weight distribution and molecular chain.Conventionally, the molecular weight of propene polymer is larger, and its melt strength is larger; But molecular weight is larger, more unfavorable for polyacrylic post-treatment processability.Therefore, consider the practical application of material, making polypropylene have wider molecular weight distribution needs; In addition, make to produce long branched chain structure in polypropylene molecular chain, also can improve polyacrylic melt strength.
In prior art, the method for conventional raising melt strength of polypropylene mainly contains: the methods such as reaction extrusion molding, radiation modification method and modulation polymerization technique technology.Reaction extrusion method is by add superoxide and other polyfunctional reactant monomers in polypropylene powder, and the technique of extruding by reaction forms polyacrylic crosslinked or long chain branching, thereby improves polyacrylic melt strength.The principle of radiation modification is to select suitable source of radiation and dosage irradiated polypropylene, causes by irradiation, reaches the object of grafting, and when irradiation, directly irradiated polypropylene makes linear chain rupture, shift and reconfigure, formation branching; Also can add polyfunctional monomer in polypropylene after, carry out again irradiation, after being excited, plays polyfunctional monomer ligation between macromole, thereby formation branched structure, makes to produce in polypropylene molecular chain long branched chain structure, thereby improves polyacrylic melt strength.
And modulation polymerization technique technology is the method for more commonly using, it is normally prepared broad molecular weight distribution polypropylene or is obtained long-chain branch polypropylene with metallocene catalyst in-situ polymerization by multiple reactors, thereby improves the melt strength of final polymkeric substance.Wherein, adopting the reactor of multiple series connection to prepare broad molecular weight distribution polypropylene commonly uses the most, it is normally selecting different amounts of hydrogen, different comonomers, be conducive to produce the polypropylene that obtains wide molecular weight distribution (MWD) in the different reactor of differing molecular weight polymers by series connection polymerization, for example: wherein a kind of reactor is conducive to produce the polymkeric substance of higher molecular weight, another kind of reactor is conducive to produce the polymkeric substance of lower molecular weight.
A kind of method of preparing the propene polymer with high fondant-strength and wide molecular weight distribution for example, is disclosed in U.S. Pat 6875826 and US7365136, it is in the endless tube-gas-phase polymerization reactor of series connection, select a kind of Ziegler-Natta catalyst with lower hydrogen response, the maximum feature of this Ziegler-Natta catalyst is exactly to adopt for example dicyclopentyl dimethoxyl silane of a kind of siloxanes that contains cycloalkyl as external electron donor, to carry out multistage (two reactors) the equal polymerization of propylene or copolymerization.By controlling the density of hydrogen of each reactor, first stage is produced the polypropylene (MFR < 0.1g/10min) of " high molecular weight block ", its weight content is 10-35%, subordinate phase is produced the polypropylene (MFR > 0.5g/10min) of " low molecular weight fraction ", its weight content is 65-90%, the MFR=0.1-20g/10min of final polymkeric substance.Reaction finally obtains having wide molecular weight distribution (M
w/ M
n> 6), linear high fondant-strength alfon.
Above-mentioned when passing through multiple reactors and preparing the method for broad molecular weight distribution polypropylene when adopting, perfect condition be make the molecular weight of the high molecular weight block that determines mechanical properties of polymer and degree of isotacticity more high better, especially possess a certain amount of " very high molecular weight block "; And the molecular weight of " low molecular weight fraction " that determines polymer-extruded performance (processing characteristics) is more low better, and need to possess more content.For propylene polymerization, the kind of external electron donor can produce significantly impact to the taxis of polymkeric substance and molecular weight distribution conventionally; But in above-mentioned patent, the component of catalyzer and characteristic do not change in two reactors, therefore in the polyreaction in two stages, catalyzer is consistent for the reaction sensibility of molecular weight regulator (hydrogen), has certain limitation like this for control or the adjusting of polymer chain characteristic.
Specifically, in the time that in catalyst system, use has the external electron donor of lower hydrogen response, as used dicyclopentyl dimethoxyl silane in patent US6875826, although can make the molecular weight of polymkeric substance higher in the first stage of producing higher molecular weight fraction, but it is in the time producing the subordinate phase of lower molecular weight fraction, due to the insensitivity that external electron donor is adjusted hydrogen, need high hydrogen content, just likely reach actual requirement.And if in catalyst system, use when thering is higher hydrogen and adjusting susceptibility external electron donor, although hydrogen usage is less when the subordinate phase of production lower molecular weight fraction, the polyacrylic extrusion performance of product is also easy to be met, but it is in the time producing the first stage of higher molecular weight fraction, molecular weight can not do enough large, thereby affect the mechanical property of the finished product.
For another polypropylene resin composite of describing in patent CN1241196A and uses thereof, also use two-stage method to obtain the polypropylene resin composite of high melting tension force; Wherein the first stage is prepared the polypropylene of high molecular under no hydrogen condition, and second segment is prepared low-molecular-weight polypropylene under hydrogen existence condition, uses identical external electron donor, as dicyclopentyl dimethoxyl silane in whole process; Preparation-obtained polypropylene can contain molecular weight and be greater than 1.5 × 10
6high molecular weight components.But it can not solve the problem that aforementioned patent US6875826 follows equally.
Although disclose the method that uses the catalyzer of two kinds of different external electron donors in different steps in prior art, for example, at patent CN1156999A " for the dual donor catalyst system of olefinic polymerization ", its first stage is used tetraethoxysilane to make external electron donor, and subordinate phase is used dicyclopentyl dimethoxyl silane to make external electron donor; Patent CN1612901A and US6686433B1 in addition similarly.Its processing step is all first to prepare small molecules polypropylene, then prepares more macromolecular polypropylene in subordinate phase, thereby obtains the polyolefine of high-crystallinity.If use method described in these patents to produce polypropylene, the first stage, while preparing small molecules, this adjusted responsive higher external electron donor also will work in subordinate phase to hydrogen, thereby cannot prepare super large molecule in subordinate phase.Equally, in these patents, also cannot obtain the propene polymer of the high fondant-strength with superior mechanical property and processing characteristics.
Summary of the invention
The problem existing in order to solve prior art, the invention provides a kind of method of direct polymerization legal system for the propylene/ethylene copolymer of high fondant-strength that adopt.
In the present invention, the melt strength that described " high fondant-strength " refers to propene polymer is more than 0.8N.
The inventor finds by repetition test, in the different propylene polymerization stage of serial operation, according to the requirement of different molecular weight fraction, by controlling in Ziegler-Natta catalyst system external electron donor component in kind and the ratio in differential responses stage, the preferably control of binding molecule amount conditioning agent consumption, again in conjunction with the adjusting of comonomer ethene add-on, can prepare and there is wide molecular weight distribution, and the propylene/ethylene copolymer that contains " very high molecular weight block " and a certain amount of " low molecular weight fraction ", this polymkeric substance has lower fusing point, well mechanical property and optical property, particularly there is very high melt strength.
Propylene/ethylene process for copolymerization of the present invention, is included in the reactor of plural serial operation, carries out propylene/ethylene copolymerizations more than two stages, wherein:
First stage: under Ziegler-Natta catalyst exists, under the polymerization temperature of 50～100 ℃, carry out the copolymerization of propylene/ethylene, the MFR of resulting polymers controls as 0.01-0.3g/10min, and described Ziegler-Natta catalyst comprises the first external electron donor component; Subordinate phase: on the basis of first stage resultant of reaction, hydrogen adds the second external electron donor component to proceed the copolymerization of propylene/ethylene under existing; The MFR of final polymkeric substance controls as 0.2-10g/10min; Wherein, described the first external electron donor adjusts susceptibility low than the hydrogen of the second external electron donor; In described each stage, all add ethene, the beguine of each stage ethene add-on is recently determined according to the load in each stage.
Preferably, in the first stage, Ziegler-Natta catalyst is composed of the following components: a kind of ingredient of solid catalyst A, a kind of organoaluminum B component and the first external electron donor component C take magnesium, titanium, halogen and internal electron donor as main ingredient; Wherein the ratio between component A and B component is counted 1: 10～500 (weight ratios) with titanium aluminum ratio; Ratio between B component and component C is 10～150: 1 (weight ratio); In subordinate phase, the ratio between organoaluminum component and the second external electron donor component of filling into is 1～50: 1 (weight ratio).
Preferably, for realizing the requirement to different molecular weight fraction, in first stage reaction, adjust the consumption of the first external electron donor component, making itself and organoaluminum ratio is 1: 15～100 (weight ratios); In subordinate phase reaction, the amount of the organoaluminum component adding by the first stage determines, fill into the second external electron donor component, making itself and organoaluminum ratio is 1: 2～20 (weight ratios).
The hydrogen add-on of first stage and subordinate phase is controlled with the requirement of final MFR.Preferably, in the first stage, hydrogen content is less than or equal to 300ppmV.
Wherein the first external electron donor component is as general formula R
1 nsi (OR
2)
4-nshown in, R in formula
1identical or different, be C
3-C
6aliphatic group branching or ring-type; R
2for C
1-C
3linear aliphatic group, for example methyl, ethyl or propyl group; N is 1 or 2.Wherein the second external electron donor component is as general formula R
3 nsi (OR
4)
4-nshown in, in formula, n is 0 or 1 or 2, R
3and R
4for identical or different C
1-C
3linear aliphatic group; Or as general formula be R
5r
6si (OR
7)
2shown in, R in general formula
7for C
1-C
3linear aliphatic group, R
5for C
1-C
3linear aliphatic group, R
6for C
3-C
6aliphatic group branching or ring-type.
Preferably wherein the first external electron donor is dicyclopentyl dimethoxyl silane and/or diisopropyl dimethoxy silane.The second external electron donor is tetraethoxysilane and/or Cyclohexylmethyldimethoxysilane.
In polymerisation process of the present invention, the catalyzer of propylene/ethylene polymerization includes but are not limited to Ziegler-Natta catalyst.The Ziegler-Natta catalyst using is by open in a large number, preferably have the catalyzer of high stereoselective, the Ziegler-Natta catalyst of high stereoselective described herein refers to can prepare the catalyzer that isotactic index is greater than 95% propene polymer.This type of catalyzer contains ingredient of solid catalyst A conventionally, is preferably the solid catalyst active ingredient of titaniferous; Organo-aluminium compound cocatalyst component B; External electron donor component C.
The specific examples that operational this class contains active solid catalyst component A is disclosed in Chinese patent CN85100997, CN93102795.0, CN98126383.6, CN98111780.5, CN98126385.2, CN99125566.6, CN99125567.4, CN00109216.2, CN02100900.7.Described catalyzer can directly use, and also can after pre-complexing and/or prepolymerization, add.Catalyzer described in Chinese patent CN85100997, CN93102795.0, CN98111780.5 and CN02100900.7, has advantage especially for high melt strength, propylene preparation method of the present invention.
Cocatalyst component B of the present invention is organo-aluminium compound, preferred alkyl aluminum compound, more preferably trialkylaluminium, as: triethyl aluminum, triisobutyl aluminium, three n-butylaluminum etc., wherein the ratio of solids containing titanium catalyst component and organo-aluminium compound cocatalyst component, counts 10～500 with Al/Ti weight ratio: 1.
According to the requirement to different molecular weight fraction, in different reactor, add the there is different qualities external electron donor of (different hydrogen response).Particularly, be that in the first reactor, the present invention need to prepare the propene polymer of high molecular weight block, in order to make this fraction have higher molecular weight, has selected one to have lower hydrogen response external electron donor in the first stage, it is as R
1 nsi (OR
2)
4-nshown in, R in formula
1identical or different, be C
3-C
6aliphatic group branching or ring-type, preferably R
1for cyclopentyl, sec.-propyl or cyclohexyl; R
2for C
1-C
3linear aliphatic group, for example methyl, ethyl or propyl group; N is 1 or 2, is preferably 2.Particular compound is as dicyclopentyl dimethoxyl silane, diisopropyl dimethoxy silane, Dicyclohexyldimethoxysilane, second, isobutyl dimethoxy silane etc.Preferably wherein the first external electron donor is dicyclopentyl dimethoxyl silane and/or diisopropyl dimethoxy silane.
The MFR value of first stage resulting polymers is controlled at 0.01-0.3g/10min, according to actual needs, conventionally be chosen in the first reactor and do not add molecular weight regulator or add the hydrogen of minute quantity (being less than or equal to 300ppmV) to make molecular weight regulator, to obtain the fraction of high molecular.
On the basis of first stage polyreaction resultant, add the second external electron donor component and molecular weight regulator (hydrogen) to carry out the polyreaction of subordinate phase, and the MFR value of controlling final polymkeric substance is controlled as 0.2-10g/10min.
The general formula of the second external electron donor component is R
3 nsi (OR
4)
4-n, in formula, n is 0 or 1 or 2.R in general formula
3and R
4for identical or different C
1-C
3linear aliphatic group, for example methyl, ethyl or propyl group; Specifically can include but are not limited to tetramethoxy-silicane, tetraethoxysilane, trimethylammonium methoxy silane, trimethylethoxysilane, dimethyldimethoxysil,ne, dimethyldiethoxysilane etc.The general formula of the second external electron donor component or be R
5r
6si (OR
7)
2, R in general formula
7for C
1-C
3linear aliphatic group, R
5for C
1-C
3linear aliphatic group, for example methyl, ethyl or propyl group, R
6for C
3-C
6aliphatic group branching or ring-type; Particular compound is as methylcyclohexyl dimethoxy silane.Wherein preferably the second external electron donor is tetraethoxysilane and/or Cyclohexylmethyldimethoxysilane.
The polyreaction of the different steps described in polymerization process of the present invention can be carried out respectively in different reactors.A concrete embodiment is: the polyreaction of first stage is carried out in the first reactor, and the polyreaction of subordinate phase is carried out in the second reactor.In the first reactor, add: a kind of ingredient of solid catalyst A, a kind of organoaluminum B component, the first external electron donor component C take magnesium, titanium, halogen and internal electron donor as main ingredient, under the condition of basic no hydrogen, carry out the copolymerization of propylene/ethylene, gained polymerisate is introduced the second reactor, add the second external electron donor component, under certain hydrogen exists, carry out the copolymerization of further propylene/ethylene.
In the first reactor, three kinds of described catalyst components can directly join in the first reactor, after the pre-complexing and/or prepolymerization that also can know altogether through industry, then join in the first reactor.Wherein the form of the reactor of pre-complex reaction can be various, its objective is that catalyst components can be obtained fully effectively to be mixed, can be continuous stirred tank reactor, annular-pipe reactor, one section of pipeline containing static mixer, can be even also the pipeline of one section of material in turbulence state.
The temperature control of pre-complexing is between-10～60 ℃, and preferred temperature is 0～30 ℃.The time of pre-complexing is controlled at 0.1～180min, and the preferred time is 5～30min.
Pass through or can also carry out optionally prepolymerization processing without the catalyzer of pre-complexing.Prepolymerization can be carried out continuously under liquid phase bulk conditions, also can carry out in inert solvent discontinuous.Pre-polymerization reactor can be continuous stirred tank, annular-pipe reactor etc.Prepolymerized temperature control is between-10～60 ℃, and preferred temperature is 0～40 ℃.Prepolymerized multiple is controlled at 0.5～1000 times, and preferred multiple is 1.0～500 times.
Described polyreaction can be in propylene liquid phase, or carries out in gas phase, or adopts liquid-gas combination technique to carry out.In the time carrying out liquid polymerization, polymerization temperature is 0～150 ℃, with 40～100 ℃ for well; Polymerization pressure should be higher than propylene the saturated vapour pressure under corresponding polymerization temperature.In the time of vapour phase polymerization, polymerization temperature is 0～150 ℃, with 40～100 ℃ for well; Polymerization pressure can be normal pressure or higher, and preferred pressure is 1.0～3.0MPa (gauge pressure, lower same).
Polymerization can be to carry out continuously, also may be carried out batchwise.Successive polymerization can be Liquid-phase reactor or the Gas-phase reactor of two or more series connection, Liquid-phase reactor can be annular-pipe reactor or stirred-tank reactor, Gas-phase reactor can be horizontal type agitated bed reactor or vertical mixing bed bioreactor or fluidized-bed reactor etc., also matched combined at random of above Liquid-phase reactor and Gas-phase reactor.Propylene/ethylene copolymerization of the present invention preferably carries out in the annular-pipe reactor of two or more series connection.
Resulting polymers of the present invention can carry out extruding pelletization by use equipment, conventionally adds the additive that this technical field is used, as oxidation inhibitor, photostabilizer, thermo-stabilizer, tinting material and filler etc. when granulation.
Propylene/ethylene copolymerization of the present invention, preferably wherein the polypropylene productivity ratio of first stage and subordinate phase is 30: 70～70: 30, more preferably 40: 60～60: 40.
Propylene/ethylene copolymerization of the present invention, preferred described ethene adds in two stages, wherein first stage ethene add-on be ethene add total amount 60～40%, subordinate phase ethene add-on be ethene add total amount 40～60%.
In the preparation method of polymkeric substance of the present invention, external electron donor consumption, kind and hydrogen and the ethene add-on of different steps while adding two reactors of series connection or periodical operation by adjustment, do not need with special catalyst; Compare to the method that only adds hydrogen concentration adjustment molecular weight distribution in prior art by difference, the present invention can use the hydrogen of less amount, can more economical means prepare high performance product, this product is compared homopolymerization high melt strength, propylene, there is better toughness and lower fusing point, be applied to the molded post-treatment energy consumption of high magnification expanded bead lower, expanded bead cohesive strength is higher, toughness is better.
Polymerization process of the present invention not only can obtain the propene polymer compared with wide molecular weight distribution, and its maximum feature is that " very high molecular weight block " content is higher, the content of " low molecular weight fraction " also can guarantee to be greater than a certain amount of simultaneously, make like this melt strength of gained propene polymer have raising significantly, also guaranteed the processing characteristics that polymkeric substance is superior simultaneously.
The preparation method of the multipolymer of the concrete a kind of propylene/ethylene with high fondant-strength of the present invention, it is characterized in that, in the annular-pipe reactor of two series connection, carry out two stage propylene/ethylene copolymerizations, wherein, first stage: under Ziegler-Natta catalyst exists, under the polymerization temperature of 50～100 ℃, be less than or equal under 300ppmV condition at hydrogen content, carry out polyreaction, the MFR of resulting polymers controls as 0.01-0.3g/10min, described Ziegler-Natta catalyst is composed of the following components: a kind of with magnesium, titanium, halogen and internal electron donor are the ingredient of solid catalyst A of main ingredient, a kind of organoaluminum B component, dicyclopentyl dimethoxyl silane C, wherein the ratio between component A and B component is counted 1: 10～500 (weight ratios) with titanium aluminum ratio, the ratio of B component and component C is 10～150: 1 (weight ratio), subordinate phase: on the basis of first stage resultant of reaction, hydrogen adds tetraethoxysilane to proceed propylene/ethylene copolymerization under existing, the amount of the organoaluminum component adding by the first stage determines, fill into tetraethoxysilane, making itself and organoaluminum ratio is 1: 1～50 (weight ratios), the MFR of final polymkeric substance controls as 0.2-10g/10min.
The present invention is the corresponding multipolymer that a kind of propylene/ethylene with high fondant-strength is provided also, and it has following feature:
(a), at 230 ℃, MFR when load 2.16kg is 0.2-10g/10min
(b) molecular weight distribution M
w/ M
n=6-20;
(c) content that molecular weight is greater than 5,000,000 fractions is more than or equal to 0.8wt%;
(d) M
z+1/ M
nbe more than or equal to 70;
(e) ethylene content 0.1wt%～20wt%.
In order to improve the melt strength of polymkeric substance, the molecular weight that improves polymkeric substance is necessary, but in order to guarantee that product has good processing characteristics (extrusion performance), in certain molecular-weight average (being certain MFR) scope, the distribution of controlling its molecular weight is very crucial.In this polymkeric substance, need to there is a certain amount of " very high-molecular weight polymer " fraction on the one hand, and on the other hand, need again to there is relatively large " low-molecular weight polymer " fraction, i.e. a kind of molecular weight distribution of relative broad range.
As everyone knows, polymer is not made up of the compound of unimodal molecular weight, even the polymer of a kind of " purely ", the mixture of the polymeric homologue that, molecular weight identical by chemical constitution is not etc. yet, structure is different is formed.The characteristic of this high molecular molecular weight heterogeneity (be molecular size range differ, uneven), is just called the polymolecularity of molecular weight.The high molecular molecular weight generally recording is all molecular-weight average.The molecular-weight average of polymkeric substance is identical, but dispersiveness is not necessarily identical.Conventionally, people use gel permeation chromatograph to measure the molecular weight distribution of polymkeric substance, can obtain number-average molecular weight, weight-average molecular weight, Z-average molecular weight or (Z+1)-average molecular weight by molecular weight distribution curve.The weighted of high molecular weight block to these molar mass average values, is the trend increasing successively, i.e. M
n< M
w< M
z< M
z+1.Conventionally, people adopt M
w/ M
nrepresent the molecular weight distribution of polymkeric substance, M
nnear the low-molecular-weight part of polymkeric substance, low molecular weight part is to M
naffect larger; M
wnear the part of high molecular in polymkeric substance, high molecular part is to M
waffect larger.In order to make polypropylene there is good over-all properties/processing characteristics, general by the molecular weight distribution M of propene polymer
w/ M
nwithin being controlled at 6-20.
But the inventor finds by repetition test, only controls M
w/ M
nthese data, can not meet the demand that the present invention prepares high fondant-strength, also " very high-molecular weight polymer fraction " must be controlled at quantitatively and in certain scope, just can reach object of the present invention.Particularly preferably " very high-molecular weight polymer fraction " and " low-molecular weight polymer fraction " is all controlled in certain scope quantitatively.Consider due to a small amount of " very high molecular weight block " not remarkably influenced M
w, but can affect significantly M
z+1.And relatively large " low-molecular weight polymer fraction " is to M
naffect greatlyr, therefore, in propene polymer of the present invention, guarantee M
z+1/ M
nit is very important being more than or equal to 70.
In the multipolymer of the propylene/ethylene of the invention described above, preferably, molecular weight is greater than 5,000,000 fraction content and is more than or equal to 1.0wt%, more preferably, is more than or equal to 1.5wt%.Preferably, the content that molecular weight is less than 50,000 fraction is more than or equal to 15.0wt%, is less than or equal to 40wt%; More preferably be more than or equal to 17.5wt%, be less than or equal to 30%.M
z+1/ M
nbe preferably more than or equal 80.Ethylene content 0.5wt%～10wt% in preferred copolymer.
Preferably, the multipolymer of this propylene/ethylene is at 230 ℃, and MFR when load 2.16kg is 1.6-6g/10min; More preferably its MFR is 2.5-6g/10min.
In addition, the present invention, by the control to each molecular weight fraction, can obtain the polymkeric substance that dispersion index PI is 6.0-20.0, is preferably 9.0-16.0.
Polymkeric substance of the present invention compared with prior art, has higher melt strength, is greater than 0.8 newton, even can exceed 2.2 newton; Its optical property and toughness are better than common homo-polypropylene, and fusing point is lower than common homo-polypropylene; Mainly can be used for preparing foaming product, biaxially oriented film, articles thermoformed therefrom and blow-molded article, be especially applied to the molded post-treatment energy consumption of high magnification expanded bead lower, expanded bead cohesive strength is higher, toughness is better.
Embodiment
To describe the present invention by specific embodiment below, but it is only to explain rather than limit the present invention.
In embodiment, polymkeric substance relevant data obtains by following testing method:
1) detection of heat-drawn wire: detect according to ASTM D648-07.
2) melt strength: the Rheoten melt strength instrument that adopts German Geottfert Werkstoff Pruefmaschinen company to produce.This instrument comprises the roller that a pair of sense of rotation is contrary, polymkeric substance is after single screw extrusion machine fusion plastification, extrude through 90 ° of circular hole die heads that turn to again, be clamped between two rollers and adopt and wait acceleration accelerated manner by uniaxial extension, drawing force can be measured by measure force element, the so-called melt strength of maximal force recording while starting to melt fracture from stretching.
3) melt flow rate (MFR) (MFR) is pressed ISO1133,230 ℃, under 2.16kg load, measures.
4) molecular weight polydispersity index PI: be that the rheometer of ARES (senior rheometer expanding system) is at 190 ℃ by the model that U.S. Rheometric Scientific Inc sells, viscosity and the modulus value of certain frequency scope working sample, the pattern of sample clamp is flat.Molecular weight polydispersity index PI=10
5/ G, G is " storage modulus (G ')-frequency curve " and " out-of-phase modulus (G ")-frequency curve " modulus value at intersection point place.Before test by resin sample at 200 ℃ of thin slices that are molded into 2mm.
5) molecular weight distribution (M
w/ M
n, M
z+1/ M
n): adopt Polymer Laboratories company of Britain to produce molecular weight and the molecular weight distribution of the IR5 detector coupling working sample of PL-GPC 220 gel permeation chromatographs and Polymer Char company of Spain product, chromatographic column is 3 series connection Plgel 10 μ m MIXED-B posts, solvent and moving phase are 1,2,4-trichlorobenzene is (containing 0.3g/1000ml oxidation inhibitor 2,6-dibutyl paracresol), 150 ℃ of column temperatures, flow velocity 1.0ml/min.
6) resin stretched intensity is pressed ASTM D638-00 measurement.
7) resin modulus in flexure is pressed ASTM D790-97 measurement.
8) IZOD notched Izod impact strength is pressed ASTM D256-00 measurement.
9) intrinsic viscosity: adopt the Y501C intrinsic viscosity analyser of VISCOTEK company of the U.S., measure by ASTM D 5225-1998 method.Solvent is perhydronaphthalene, 135 ℃ of probe temperatures.
10) solubles content: adopt the CRYSTEX instrument of PolyChar company of Spain to record, solvent is trichlorobenzene.Its result cold xylene solvend Data correction of the polymkeric substance recording according to ASTM D5492-2006 standard.
11) ethylene content: the ethylene content on Nicdet Magna-IR760 in working sample, sample is put between two KBr salt sheets, be placed under infrared lamp and warm, be pressed into film, under normal temperature, measure.Characteristic peak optical density(OD) is obtained by baseline method.Propylene nuclear-magnetism being obtained with 1gA1152/A723 divides and mole likens figure to, obtains quantitative curve: 1g A
1152/ A
721=0.0212C
3-1.1121, utilize this equation, sample is carried out to infrared analysis, just can carry out quantitatively the segment composition of multipolymer.
12) fusing point: by DSC method mensuration, polyacrylic dsc analysis carries out on Perkin-Elmer DSC-7, first the polypropylene specimen of about 5mg is raised to 200 ℃ with the speed of 10 ℃/min, maintain 5min, eliminate thermal history, then drop to 50 ℃ with identical speed, record Tc Tc, be warmed up to 200 ℃ with 10 ℃/min speed again, record fusing point Tm.
13) mist degree: test according to GB 2410.
Embodiment 1:
Polyreaction is carried out on a set of polypropylene pilot plant.Its major equipment comprises prepolymerization reactor, first ring pipe reactor and the second annular-pipe reactor.Polymerization process and step are as follows:
(1) prepolymerization:
Primary Catalysts (the solid catalyst active ingredient of titaniferous) adopts the method that in Chinese patent CN93102795, embodiment 1 describes to obtain, its Ti content: 2.4wt%, Mg content 18.0wt%, n-butyl phthalate content: 13wt%.
Primary Catalysts, promotor (triethyl aluminum), the first external electron donor (dicyclopentyl dimethoxyl silane, DCPMS) after the pre-contact of 10 ℃, 20min, add continuously prepolymerization reactor to carry out prepolymerization, prepolymerization is carried out under propylene liquid phase bulk environment, temperature is 15 ℃, the residence time is about 4min, and under this condition, the pre-polymerization multiple of catalyzer is about 120-150 times.The triethyl aluminum flow that enters prepolymerization reactor is 6.33g/hr, and two cyclopentyl dimethoxy silane flows are 0.33g/hr, and Primary Catalysts flow is about 0.5g/hr.
(2) copolymerization of propylene/7 alkene:
Pre-polymerization rear catalyst enters in the annular-pipe reactor of two series connection, completes the copolymerization of propylene/ethylene under the propylene liquid phase bulk environment in annular-pipe reactor.Wherein the ethene add-on of the first endless tube is 7000ppm (volumetric molar concentration), and the ethene add-on of the second endless tube is 5000ppm (volumetric molar concentration).Two 70 ℃ of endless tube polymeric reaction temperatures, reaction pressure 4.0MPa.The processing condition of gate ring pipe reactor, the productivity ratio that makes first, second endless tube is approximately 45: 55.
In the charging of first ring pipe reactor, do not add hydrogen, the density of hydrogen < 10ppmV that on-line chromatograph detects, adds a certain amount of hydrogen in the second annular-pipe reactor charging, and the density of hydrogen that on-line chromatograph detects is 4700ppmV.
Because these catalyst components directly enter first ring pipe reactor after prepolymerization, first ring pipe reactor no longer includes any other charging except propylene and ethene, therefore, in first ring pipe reactor, triethyl aluminum/dicyclopentyl dimethoxyl silane (Al/Si-I) is 19.0 (weight ratios) than the ratio being in catalyst prepolymer.
In the second annular-pipe reactor, add the tetraethoxysilane (TEOS) into 0.67g/hr, therefore, triethyl aluminum/tetraethoxysilane in the second annular-pipe reactor (Al/Si-II) is than being 9.4 (weight ratios).Concrete technology condition is in table 1.
After flash separation goes out propylene, ethene, remove the activity of catalyst in reactor from the second endless tube polymkeric substance out through wet nitrogen, polymkeric substance, through heat drying, obtains polymer powders.
In the powder that polymerization is obtained, add IRGAFOS 168 additives of 0.1wt%, IRGANOX 1010 additives of 0.2wt% and the calcium stearate of 0.05wt%, use twin screw extruder granulation.Gained pellet is carried out to performance test by existing relevant ASTM standard.
Embodiment 2:
With embodiment 1, just become 35000ppmV in the ethene add-on of first ring pipe reactor; The ethene add-on of the second annular-pipe reactor is adjusted into 30000ppmV; Meanwhile, the amounts of hydrogen in the second annular-pipe reactor is adjusted into 9000ppmv.
Comparative example 1:
With embodiment 2, just Al/Si is adjusted into 10, and amounts of hydrogen in the second annular-pipe reactor is adjusted into 10000ppmv; The second annular-pipe reactor is no longer added external electron donor.
Concrete technology parameter, resulting polymers analytical results and the polymer physics performance of each embodiment and comparative example are listed in table 1～4.
Table 1. embodiment polymerization process condition
Table 2. embodiment polymers analysis results (1)
Table 3. embodiment polymers analysis results (2)
In table: F280z is the polypropylene that China petroleum Chemicals Co., Ltd. Town Hai Lian Hua branched Corporation produces
Table 4. embodiment polymer physics performance
Data from form, comparative example 1 because not adding an external electron donor that hydrogen response is high in subordinate phase reaction, its polypropylene product small molecular amount is inadequate, and the melting index of product is low, and extrusion performance (processing characteristics) is very poor and limit its use.
In addition, in actual production, the density of hydrogen (10000ppm) that in comparative example 1, subordinate phase the is used high value that substantially reaches capacity; Under non-critical operational condition, in reactor, hydrogen can not infinitely increase, when density of hydrogen is greater than 10000ppm, not only can cause damage to appliance arrangement, in follow-up propylene, hydrogen removes also very difficult, finally, follow with carrying hydrogen in propylene and cause the interior density of hydrogen of the first reactor uncontrollable at low level.Therefore, can not make propene polymer meet the particular product performance parameters described in the present invention by simple control density of hydrogen.
Claims (8)
1. a preparation method for the propylene/ethylene copolymer of high fondant-strength, is characterized in that, in the reactor of plural serial operation, carries out two above propylene/ethylene copolymerizations of stage, wherein:
First stage: under Ziegler-Natta catalyst exists, under the polymerization temperature of 50～100 ℃, carry out propylene/ethylene copolymerization, the MFR of resulting polymers controls as 0.01-0.3g/10min, and described Ziegler-Natta catalyst comprises the first external electron donor component;
Subordinate phase: on the basis of first stage resultant of reaction, hydrogen adds the second external electron donor component to proceed propylene/ethylene copolymerization under existing;
The MFR of final polymkeric substance controls as 0.2-10g/10min;
Wherein, described the first external electron donor adjusts susceptibility low than the hydrogen of the second external electron donor; The first external electron donor is dicyclopentyl dimethoxyl silane and/or diisopropyl dimethoxy silane, and the second external electron donor is tetraethoxysilane and/or Cyclohexylmethyldimethoxysilane;
In described each stage, all add ethene, the beguine of each stage ethene add-on is recently determined according to the load in each stage.
2. preparation method according to claim 1, in first stage, Ziegler-Natta catalyst is composed of the following components: a kind of ingredient of solid catalyst A, a kind of organoaluminum B component and the first external electron donor component C take magnesium, titanium, halogen and internal electron donor as main ingredient; Wherein the ratio between component A and B component is counted 1:10～500 weight ratio with titanium aluminum ratio; Ratio between B component and component C is 10～150:1 weight ratio; In subordinate phase, the ratio between organoaluminum component and the second external electron donor component of filling into is 1～50:1 weight ratio.
3. preparation method according to claim 2, in the first stage, adjusts the consumption of the first external electron donor component, and making itself and organoaluminum ratio is 1:15～100 weight ratio; In subordinate phase, the amount of the organoaluminum component adding by the first stage determines, fill into the second external electron donor component, making itself and organoaluminum ratio is 1:2～20 weight ratio.
4. preparation method according to claim 1, in the first stage, hydrogen content is less than or equal to 300ppmV.
5. preparation method according to claim 1, wherein the productivity ratio of first stage and subordinate phase is 30:70～70:30.
6. according to the preparation method described in any one in claim 1 to 5, wherein, described ethene adds in two stages, first stage ethene add-on be ethene add total amount 60～40%, subordinate phase ethene add-on be ethene add total amount 40～60%.
7. the propylene/ethylene copolymer that utilization is made according to the preparation method described in any one in claim 1 to 6, it has following characteristics:
(a), at 230 ℃, MFR when load 2.16kg is 0.2-10g/10min;
(b) molecular weight distribution M
w/ M
n=6-20;
(c) content that molecular weight is greater than 5,000,000 fractions is more than or equal to 0.8wt%;
(d) M
z+1/ M
nbe more than or equal to 70;
(e) ethylene content is 0.1wt%～20wt%.
8. propylene/ethylene copolymer according to claim 7, it has following characteristics:
(a), at 230 ℃, MFR when load 2.16kg is 1.6-6g/10min;
(b) molecular weight distribution M
w/ M
n=6-20;
(c) content that molecular weight is greater than 5,000,000 fractions is more than or equal to 1.0wt%;
(d) M
z+1/ M
nbe more than or equal to 80;
(e) ethylene content is 0.5wt%～10wt%;
(f) content that molecular weight is less than 50,000 fractions is more than or equal to 17.5wt%, is less than or equal to 30%;
(g) the dispersion index PI of polymkeric substance is 9.0-16.0.
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| US9068030B2 (en) * | 2010-01-22 | 2015-06-30 | China Petroleum & Chemical Corporation | Propylene homopolymer having high melt strength and preparation method thereof |
| CN105622819B (en) * | 2014-10-31 | 2018-09-21 | 中国石油化工股份有限公司 | A kind of preparation method of the impact polypropylene material of high fondant-strength |
| CN105622809B (en) * | 2014-10-31 | 2019-03-22 | 中国石油化工股份有限公司 | A kind of preparation method of the impact polypropylene of low VOC content |
| CN110016097B (en) * | 2018-01-10 | 2021-12-31 | 中国石油化工股份有限公司 | Ethylene-propylene random copolymer with low dissolution, low melting point, narrow molecular weight distribution and stable thermal oxygen, and preparation method and application thereof |
| CN110105677A (en) * | 2019-05-27 | 2019-08-09 | 苏州市炽光新材料有限公司 | PP foam material and preparation method thereof based on recycled plastic |
| CN111116785A (en) * | 2019-12-27 | 2020-05-08 | 浙江卫星能源有限公司 | Propylene polymerization method and apparatus |
| CN113667225B (en) * | 2020-05-13 | 2023-07-18 | 中韩(武汉)石油化工有限公司 | Special material for polypropylene waterproof coiled material and production method thereof |
| CN113667221B (en) * | 2020-05-13 | 2023-07-18 | 中韩(武汉)石油化工有限公司 | Polypropylene resin for waterproof coiled material production |
| CN115073642B (en) * | 2021-03-11 | 2023-11-28 | 中国石油天然气股份有限公司 | High melt strength polypropylene resin and preparation method and application thereof |
| CN115073644A (en) * | 2021-03-11 | 2022-09-20 | 中国石油天然气股份有限公司 | Copolymerized high-melt-strength polypropylene resin and preparation method and application thereof |
| CA3228273A1 (en) | 2021-08-04 | 2023-02-09 | China Petroleum & Chemical Corporation | Modified flexible polypropylene insulating material and preparation method and use thereof |
| TW202317695A (en) * | 2021-10-27 | 2023-05-01 | 大陸商中國石油化工科技開發有限公司 | Polypropylene microsphere and preparation method therefor, 3D printing raw material, and use |
| CN115678168A (en) * | 2022-10-21 | 2023-02-03 | 中国石油化工股份有限公司 | Low-melting-point polypropylene resin for foaming and preparation method thereof |
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| CN1091748A (en) * | 1993-03-29 | 1994-09-07 | 中国石油化工总公司 | The spherical catalyst of for olefines polymerization |
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| CN1091748A (en) * | 1993-03-29 | 1994-09-07 | 中国石油化工总公司 | The spherical catalyst of for olefines polymerization |
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