CN1184244C - Polyethylene resin and pipe and joint using the same - Google Patents

Abstract

The present invention provides polyethylene resin, and a pipe and a connecting piece prepared by the polyethylene resin, wherein the polyethylene resin has good rigidity, impact resistance and long term durability (the environmental stress resistance, the long term hydrostatic strength and the slow fission hyperplasia resistance (SCG) of the pipe). The present invention is linear polyethylene which is prepared when ziegler natta catalysts exist, and has the following physical properties (1) to (6): (1) under a testing load of 5.00kg, the speed rate (MFR) of a fused mass is measured to 0.20 to 0.50g every 10 minutes under 190 DEG C; (2) a flow ratio (FR) is 65 to 130; (3) density (rho) is 0.948 to 0.952 g/cm#+3; (4) a relaxation parameter H is equal to or lower than 1.90*10#+<-8> dyne /cm#+<2> obtained by a stress test; (5) in integral eluting temperature regions, the integral of the weight of each high molecular weight part and the whole elute weight ratio (WH) in each multiple eluting temperature region is 39 to 45% of weight, and the weight of each high molecular weight part is measured by a cross fractionation (TREF-SEC) which comprises a temperature rise elution fractionating (TREF) and a size exclusion chromatography (SEC); the peak temperature (TH) of an elution curve of the weight of each high molecular weight part calculated in each multiple eluting temperature region is equal to or lower than 96.5 DEG C, and the weight of each high molecular weight part is measured by the cross fractionation (TREF-SEC) which comprises the temperature rise elution fractionating (TREF) and the size exclusion chromatography (SEC); the peak temperature (TL) of the elution curve of the weight of each low molecular weight part calculated in each multiple eluting temperature region is equal to or higher than 99.2 DEG C. The weight of each low molecular weight part is measured by the TREF-SEC.

Description

Polyvinyl resin and with the pipe and the web member of this resin

Invention field

The present invention relates to the good polyvinyl resin of rigidity, shock-resistance and long durability under stress (environmental stress resistance of pipe, long-term statics of fluids intensity and anti-slow breach hyperplasia (SCG)); With pipe and web member with these polyvinyl resins.

Background technology

Polyethylene tube and web member in light weight is easy to handle, its rigidity of no burn into your pupil is embedded in undergroundly with tolerance, and flexible your pupil is with then underground mobile.Because these features, its consumption significantly increases in recent years.Require polyethylene tube or web member to have following performance: (1) above-mentioned performance; (2) shock-resistance height, the impact that when being enough to stand to install or installation back is applied; (3) good long term weather resistance (particularly, environmental stress resistance creep properties, long-term statics of fluids intensity and anti-slow breach hyperplasia (SCG)) is arranged under the pressure of gas or tap water.Above-mentioned performance (1) and (2) are met in actual the use.About long durability (3), it is said at normal temperatures 8Mpa or bigger but be lower than 10Mpa hoop stress in depress, according to ISO 12162, the material (PE80) with the weather resistance in 50 years has been used for flue.Yet the long durability deficiency of this material is used for depressing in high.Recently, brought into use it is said at normal temperatures 10Mpa or bigger but be lower than 11.2Mpa hoop stress in depress, according to ISO 12162, have the material (PE100) of the weather resistance in 50 years.Yet, particularly on hot conditions, the PE100 material since stress concentration appear at small, the defective part of structure and can not produce brittle crack fully.From reliability consideration, produce brittle crack when not wishing under condition of high voltage life-time service.

The polyethylene tube of long durability will stand so-called tensile creep property testing, promptly in a circumferential direction as the position stretch stress in depress the prolonged application of anti-pipe and the ESCR under the tensile stress, i.e. the persistence of proof stress be full of cracks.Therefore, in order to improve the long durability of polyethylene tube, must improve so-called tensile creep and these two kinds of performances of ESCR under the tensile stress.About so-called tensile creep under the raising tensile stress and the method for ESCR, known have the method that increases molecular weight of polyethylene, and for the method that improves the ESCR performance, reduce density (ρ) and think effectively.Increase molecular weight but reduce density, produced as problems such as pipe extrusion performance and plastic-blasting when web member is made obviously degenerate.On the other hand, it also is not preferred reducing density (ρ), and this is because this has reduced the rigidity of the pipe of being made by this polyethylene, the rapid variation of pressing in this polyethylene can not bear.

An object of the present invention is to overcome the above-mentioned deficiency in the routine techniques and the polyvinyl resin with following performance is provided, it has heat-resisting creep properties and ESCR under the tensile stress of improvement, significantly improve long-term persistence and good mouldability or plasticity and production efficiency, kept good rigidity and shock-resistance simultaneously; And the pipe and web member (as being connected the web member of long tube and pipe) made with this polyvinyl resin.

Disclosure of an invention

In order to overcome the problems referred to above, the inventor has carried out deep investigation.As a result, find to reach above-mentioned target, thereby finish the present invention by with ziegler natta catalyst linear polyethylene preparation and that have specific physicals.

Therefore, one aspect of the present invention provides ziegler natta catalyst linear polyethylene preparation and that have following physicals (1)-(6):

(1) be the 0.20-0.50g/10 branch in the melt speed (MFR) that under 190 ℃, records under the 5.00kg testing load;

(2) throughput ratio (FR) is 65-130,

(3) density (ρ) is 0.948-0.952g/cm ³,

(4) be 1.90 * 10 by following equation (II) relaxation parameter H expression and that can obtain by stress test ^-8Dyne/cm ²Or lower,

(5) in whole all eluting temperature zones, the integration of the amount of every kind of high molecular part calculating in each many eluting temperatures district and the ratio (WH) of total elution amount, be 39-45% weight, the amount of described every kind of high molecular part is measured by the intersection classification (TREF-SEC) that comprises temperature rise elution fractionation (TREF) and size exclusion chromatography, (SEC).

The peak temperature (TH) of the elution curve of the amount of every kind of high molecular part (6) calculating in each many eluting temperatures district is 96.5 ℃ or lower, and the amount of described every kind of high molecular part is measured by the intersection classification (TREF-SEC) that comprises temperature rise elution fractionation (TREF) and size exclusion chromatography, (SEC); With

The peak temperature (TL) of the elution curve of the amount of every kind of low molecular weight part calculating in each many eluting temperatures district is 99.2 ℃ or higher, and the amount of described every kind of low molecular weight part is measured by TREF-SEC.

$H=-E\left({10}^3\right)\frac{\mathrm{LogE}\left({10}^3\right)-\mathrm{LogE}\left({10}^0\right)}{\mathrm{Log}{10}^3-\mathrm{Log}{10}^0}$

Loose modulus when wherein, E (ι) shows time ι.

A second aspect of the present invention also provides every kind of pipe and web member that comprises above-mentioned polyvinyl resin.

A third aspect of the present invention, aforementioned tube and web member also are provided, when under 80 ℃ constant stress, carrying out the environmental stress cracking test, the performance that pipe and web member are every kind is: rupture time is 20 hours or longer under the 6MPa initial load, and rupture time is 80 hours or longer under the 4MPa initial load.

Implement best mode of the present invention

Introduce the present invention below with reference to embodiment is more detailed.

Polyvinyl resin

Prepare the used polyvinyl resin of the present invention (also can be described as " linear polyethylene ") with Ziegler-Natta catalyst.Preferably use the high reactivity Ziegler-Natta polymerizing catalyst of forming by ingredient of solid catalyst that contains Mg, Ti and halogen and organo-aluminium compound, by ceridust or copolymerization of ethylene and C3-20 alpha-olefin and obtain desired density (ρ) in certain proportion.The example of C3-20 alpha-olefin comprises the compound of being represented by formula R-CH=CH2, and wherein R represents the C1-12 alkyl, for example propylene, 1-butylene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-amylene and 1-octene.

The example of used polymerization process comprises slurry polymerisation, vapour phase polymerization and solution polymerization when the preparation polyvinyl resin.

The present invention is used to manage with the polyvinyl resin that is connected and prepares with low pressure multistep polymerization method under different reaction conditionss at least two reactors.Be specially, in the present invention, by regulating MFR5, density (ρ) and throughput ratio FR respectively at 0.20-0.50g/10 branch, 0.948-0.952g/cm ³Prepare polyethylene with 65-130, in wherein whole all eluting temperature zones, the integration of the amount of every kind of high molecular part calculating in each many eluting temperatures district and the ratio (WH) of total elution amount, be 39-45% weight, the amount of described every kind of high molecular part is measured by the intersection classification (TREF-SEC) that comprises temperature rise elution fractionation (TREF) and size exclusion chromatography, (SEC); The peak temperature (TH) of the elution curve of the amount of every kind of high molecular part calculating in each many eluting temperatures district is 96.5 ℃ or lower, the peak temperature (TH) of the elution curve of the amount of every kind of low molecular weight part calculating in each many eluting temperatures district is 99.2 ℃ or higher, and relaxation parameter H is 1.90 * 10 ^-8Dyne/cm ²Or it is lower.

The inventor finds: density (ρ) of being carried out in routine techniques and the independent variation of MFR are not enough to improve the weather resistance of pipe; Weather resistance depends on WH, TL and TH and the relaxation parameter H that available TREF-SEC measures.Control MRF5, throughput ratio FR and density (ρ) are in above-mentioned predetermined scope and regulate WH, TL and TH and Parameter H in target zone, can obtain each and all have persistent polyvinyl resin, pipe and web member.In addition, by to regulate three parameters be MRF5, throughput ratio FR and density (ρ) in above-mentioned predetermined scope or two of setting in these three parameters regulate remaining parameter, may command WH, TL and TH and relaxation parameter H simultaneously in above-mentioned scope in pre-determined range.

Polyvinyl resin by this method preparation is the linear polyethylene resin with following physicals (1)-(6):

(1) be the 0.20-0.50g/10 branch in the melt speed (MFR) that under 190 ℃, records under the 5.00kg testing load; Be preferably the 0.22-0.45g/10 branch; 0.25-0.43g/10 branch particularly;

(2) throughput ratio (FR) is 65-130, is preferably 70-120, particularly 80-115;

(3) density (ρ) is 0.948-0.952g/cm ³, be preferably 0.949-0.951g/cm ³,

(4) be 1.90 * 10 by following equation (II) relaxation parameter H expression and that can obtain by stress test ^-8Dyne/cm ²Or lower, be preferably 1.85 * 10 ^-8Dyne/cm ²Or lower,

(5) in whole all eluting temperature zones, the integration of the amount of every kind of high molecular part calculating in each many eluting temperatures district and the ratio (WH) of total elution amount, be 39-45% weight, the amount of described every kind of high molecular part is measured by the intersection classification (TREF-SEC) that comprises temperature rise elution fractionation (TREF) and size exclusion chromatography, (SEC).

The peak temperature (TH) of the elution curve of the amount of every kind of high molecular part (6) calculating in each many eluting temperatures district is 96.5 ℃ or lower, and the amount of described every kind of high molecular part is measured by the intersection classification (TREF-SEC) that comprises temperature rise elution fractionation (TREF) and size exclusion chromatography, (SEC); With

The peak temperature (TL) of the elution curve of the amount of every kind of low molecular weight part calculating in each many eluting temperatures district is 99.2 ℃ or higher, and the amount of described every kind of low molecular weight part is measured by TREF-SEC.

The MFR5 of linear polyethylene is less than the 0.20g/10 timesharing, and flowability significantly reduces, and the become production efficiency of deficiency and pipe of mouldability or formability is unsatisfactory.In addition, can not mould web member from this polyethylene Wang, even or may, the obvious variation of the outward appearance of the web member that obtains thus.On the other hand, when MFR5 surpasses 0.05g/10g, the sagging when resin of taking out of from die head might cause molding, it hinders molded well and has damaged by the pipe and the web member that generate resins, and they only have insufficient long durability and shock-resistance.Therefore, not preferred MFR surpasses above-mentioned scope,

Throughput ratio FR is one and measures the physicals that molecular weight of polyethylene distributes.It is expressed as: the amount of extruding 10 minutes resins under 190 ℃ of following 11.6kg load from fusion index instrument is divided by the amount of extruding 10 minutes resins under the 1.16kg load from fusion index instrument.Throughput ratio FR is more little, and poly molecular weight is narrow more.On the contrary, throughput ratio FR is big more, and molecular weight distribution is wide more.When FR less than 65 the time, mouldability or film-forming properties variation.When throughput ratio FR surpassed 130, because the influence of low molecular weight part, shock-resistance might reduce.When density (ρ) less than 0.948 the time, the rigidity of the pipe of being made by this polyethylene becomes extremely not enough, and when they being embedded in when underground since the pressure of the earth may be out of shape and can not bear in the obvious rising of pressure.When it surpassed 0.952, it is not enough that the long durability of pipe becomes.Therefore, preferred density does not surpass above-mentioned scope.

The following method of root a tree name can be measured poly crystal by TREF-SEC and distribute and molecular weight.In the method for fractional steps of TREF post and use under the different solvent temperatures and can be divided into polyethylene fractions that to have a low-crystalline paramount crystalline.Fractionated cut is thus joined in the SEC post continuously, thereby but their root a tree name molecular sizes are molecular-weight gradation.By these operations, in each eluting temperature zone, obtain elution amount (Wt%) and molecular weight distribution (dW/d (logM) is with respect to logM).

Measure ratio (WH), the elution peak temperature (TH) of high molecular cut and the elution peak temperature (TL) of low-molecular-weight fraction of high molecular cut according to aforesaid method.The polyvinyl resin aforesaid method classification that under different reaction conditionss, prepares at least two reactors with low pressure multistep polymerization method, thereby in each eluting temperature zone, obtain having and measure distribution, i.e. low-molecular-weight fraction peak and high molecular cut peak having divided of two peaks.Distribute by two lognormalitys of match (fitting) (log-normal), the amount of having divided with two peaks in each eluting temperature zone is distributed carry out the peak classification, become two cuts.In its eluting temperature zone, lower molecular weight side and high molecular side are decided to be low-molecular-weight fraction and high molecular cut respectively.The total amount stdn of low-molecular-weight fraction that is obtained by the peak classification and high molecular cut equaled the elution amount (weight %) in the corresponding eluting temperature zone, and as harmonic component cut amount.Polymer cut amount.At the integration of all eluting temperatures zone inner macromolecule amount cuts ratio (WH) as the high molecular cut.WH is lower than 39% weight and means that the amount of high molecular cut is little, and hint increases the molecular weight of high molecular cut in the poly situation that MRF5 and density (ρ) prepare in above-mentioned scope.This has caused significantly reducing the consistency of two cuts, and this has caused deterioration of impact resistance or increased flake, thereby has made the surface deterioration of pipe.On the other hand, when WH surpassed 45% weight, the molecular weight of high molecular cut diminished, and long durability significantly reduces.Simultaneously, this molecular weight that shows low-molecular-weight fraction raises relatively, and this causes the remarkable variation and the not satisfied extrusion moulding of liquid.

By the amount of high molecular cut in each eluting temperature zone with respect to each eluting temperature mapping and the match normal distribution obtains in 80-110 ℃ of temperature range curve, be used as elution curve.Its peak temperature is as the elution peak temperature (TH) of high molecular cut.

Determine the peak eluting temperature of low-molecular-weight fraction with similar approach.Yet, do not use the amount of the low-molecular-weight fraction in each eluting temperature zone, and logM=5 ± 0.1M (M: the amount of cut molecular weight) in using in each eluting temperature zone corresponding to low-molecular-weight fraction.This be because have molecular weight be 30000 or the situation of the cut of lower (logM＜4.5) under, its eluting temperature (for example has significant dependency to molecular weight, referring to Journal of Polymer Science:Polymer Physics Edition, Vo.20,441-445 (1882)), thereby in being rich in low-molecular-weight fraction with the cut that is not more than 30000 molecular weight, by mensuration have 30000 or the elution curve of the cut of bigger specified molecular weight can accurately reflect their performance.Therefore the peak temperature of measuring is as the elution peak temperature (TL) of low-molecular-weight fraction.

Each is crystalline index for TL and TH, and this can be appreciated that from their measuring method.TL or TH are big more, show that crystallinity is high more, and on the contrary, TL or TH are low more, show that crystallinity is low more.When TL is lower than 99.2 ℃ and TH and is higher than 96.5 ℃, the persistence of creep resistant and anti-stress crack, promptly the ESCR performance under the tensile stress obviously reduces.Especially at high temperature, owing to the brittle crack that the stress concentration that produces at small place produces, the inevitable defective part of structure.As mentioned above, improve poly molecular weight and to reduce its density all effective to the ESCR performance of improving under stretch-proof creep properties and the tensile stress.The simple molecular weight that increases is not desirable with reducing density, and this is that this causes mouldability or remarkable variation of plasticity and rigidity variation because as mentioned above.By setting TL, promptly improve because lower molecular weight and the crystallinity of the cut that the ESCR performance of improving under creep resistant and the tensile stress do not worked, thereby keep rigidity at 99.2 ℃ or higher; And by setting TH at 96.5 ℃ or lower, thereby reduce improving the crystallinity that ESCR performance under creep resistant and the tensile stress plays the cut of very big effect, promptly reduce density (ρ), thereby can obtain rigidity and long-term persistence.

Relaxation parameter H is a parameter that is obtained by following theory.The poly long durability of H with specified range is good.Consider in order to make polyethylene have long durability, require the amount of the cut that its stress can be loose at short notice should be big.Being evaluated as of known stress relaxation: assess variation, and carry out its assessment by the time-dependent manner of measuring the modulus of measuring divided by the strain of this degree by the strain of the sample that produces when applying strain to a certain degree to it.In the reality, by measuring modulus, and reduce principle, obtain the loose modulus in long-time with temperature-time with variation of temperature.Obtain the method for loose distribution function by Schwarz-Staverman from this loose modulus, people such as L eaderman propose (referring to " Buttai no Henkeigaku ", Published by Seibundo Shinkosha in 1972, page 201-204).Their report of root a tree name, relaxation spectra h (j) can be provided by following formula when time j:

$h\left(j\right)=\underset{k\&RightArrow;\&infin;}{\lim }\frac{{(-1)}^k}{(k-1)!}{\left(\mathrm{kj}\right)}^k{E}^{\left(k\right)}\left(\mathrm{kj}\right)$

(wherein E (k) (kj)=dkE/dtk, and the loose modulus can multiply by time t by differential k the time obtains.)

The approximation of k=1 in formula (II) provides following formula (III):

$h\left(j\right)=-j\frac{\mathrm{dE}\left(j\right)}{\mathrm{dt}}=\frac{\mathrm{dE}\left(j\right)}{d\left(\ln j\right)}=-E\left(j\right)\frac{d\left(\ln E\right)}{d\left(\ln j\right)}$

As long-time (j=10 ³Second) the loose distribution function h (10 under ³) when being represented by H, H can be provided by following formula (IV):

$H=-E\left({10}^3\right)\frac{\mathrm{dLogE}\left(j\right)}{\mathrm{dLogj}}{|}_{j={10}^3}$

During the value when using, measured, can obtain down formula V at 100 seconds:

$\frac{\mathrm{dLogE}}{\mathrm{dLogj}}=\frac{\mathrm{LogE}\left({10}^3\right)-\mathrm{LogE}\left({10}^0\right)}{{\mathrm{Log}10}^3-{\mathrm{Log}10}^0}$

Therefore H can be calculated with experimental value by following formula (I),

$H=-E\left({10}^3\right)\frac{\mathrm{LogE}\left({10}^3\right)-\mathrm{LogE}\left({10}^0\right)}{{\mathrm{Log}10}^3-{\mathrm{Log}10}^0}$

Therefore the relaxation parameter H (dyne/cm that provides by following formula (I) ²) corresponding to specified time (10 ³Second) loose distribution function, and available experimental value is measured.The H value that drops in the above-mentioned scope is hinting that fully long-time interior loose distribution function is little, represents that the ratio of its very long hour loose part of internal stress is little.Therefore, the preferred H value in above-mentioned scope.

Here the polyethylene that obtains has: the result's of environmental stress cracking test performance is under 80 ℃ constant stress, and rupture time is 20 hours or longer under 6MPa incipient extension load, and rupture time is 80 hours or longer under the 4MPa initial load.

During environmental stress cracking is tested under 80 ℃ constant stress, had under 6MPa incipient extension load rupture time and be 20 hours or lower, rupture time is 80 hours or the material of lower performance more under 4MPa incipient extension load, the persistence of tensile creep and proof stress be full of cracks, i.e. ESCR inequality under the tensile stress.Because small, the defective part of structure that stress concentration appears at, especially at high temperature, pipe or the web member made by this material might produce brittle crack.Consider reliability, produce brittle crack and do not wish to want.

Optional component

Under the situation of not remarkably influenced of scope advantage of the present invention, can in polyvinyl resin of the present invention, add optional components.The example of optional components comprises the additive or the Synergist S-421 95 of known or conventional use, for example, oxidation inhibitor, neutralizing agent, anti-weather activator, froth suppressor, dispersion agent, static inhibitor, surface slip agent, thermo-stabilizer, photostabilizer, UV light absorber, lubricant, metal inactivator, sterilant, mould inhibitor, tinting material, releasing agent and processing aid.These components can be incorporated in from the former any step of expecting preparation pipe or web member of molding and add when needing.

If need, above-mentioned polyvinyl resin and optional components can directly join mould machine to carry out molding.Yet, before molding, often wish under melted state, to mediate these components, and the material of this kneading made expected into moulding material in advance.Usually, by the extrusion molding tubulation, and come tubing sub-connecting member etc. by plastic-blasting.Not only can carry out individual layer but also can carry out multilayer molded.

Embodiment

Introduce the present invention by specific embodiment is more detailed.In an embodiment, by following method assessment physicals.

.MFR5: root a tree name JIS K7210 test

. density (ρ): root a tree name JIS K7112 test

. shock-resistant: root a tree name JIS K7110 (23 ℃) test I zod shock strength.

Modulus in flexure: root a tree name ASTM D747 test.

ESCR: as described in JIS K6760, under constant stress, using instrument under the following condition, test environmental stress resistance cracking: 80 ℃ of water temperatures, use the test soln of 1% higher alcohols in sodium sulfonate, the incipient extension load is 6MPa or 4MPa.Use has the dark laser breach of 0.4mm at the middle part 1mm is thick * and the wide presspahn of 6mm is as sample, the narrowest part of drawing plate.

.TREF-SEC

Use " CFC T-100 " (trade name :) to test with the product of Dia Instruments.

Sample dissolution to be tested as in the orthodichlorobenzene of solvent, and is poured into the solution that generates in the TREF center pillar.Under 40 ℃, solution is joined SEC pole unit (" AD806MS " comprises three posts, the product of Showa Denko) from the TREF post.When in the SEC post, passing through the molecular sieve classification, heating TREF post.Afterwards, repeat heating and join the SEC post, up to 140 ℃, obtain the chromatogram under each eluting temperature with 5 ℃ intervals.Become molecular weight distribution in each eluting temperature zone by two log normal distributions of match, the peak is classified into two cuts with two peaks.In each eluting temperature zone, use the lower molecular weight side respectively.The high molecular side is as low-molecular-weight fraction.The polymer cut calculates WH, TL and TH.

. stress relaxation: use Co., the light-spot galvanometer that Ltd. makes by Oku Seisakusho " HRS-100 " test.Use the sample of the 30mm * 5mm * 0.3mm of compression moulding preparation.Stress relaxation after test is impacted each sample with the speed of 1mm/s under the temperature that changes, and be evaluated at principal curve under 30 ℃.

. long term hydrostatic strength; 65 Φ forcing machines with Gunze Sangyo Inc. manufacturing, spiral die and vacuum cooling water by IKG Co.Ltd. manufacturing, under the condition in the rate of withdraw of about 20 ℃ bath temperature and about 65cm/ branch under about 210 ℃ resin temperature, the formation external diameter is that 60mm, wall thickness are the pipe of 5.5mm.Root a tree name ISO1167 assesses the creep resistant of this pipe under the internal pressure of regulating, and makes the hoop stress of pipe be 5.5MPa at 80 ℃.Confirm that by this test the resistance to persistence at 80 ℃ was at least 165 hours and 5.5MPa, as described in ISO4427.Test is also proceeded total 10000 hours in addition, observes and confirm whether to occur brittle crack.

Embodiment 1

The preparation solid catalyst

At 150 ℃ of Mg (OEt) that mix 77.9kg down ₂, 101.3kg Ti (OBu) ₃The n-BuOH6 of Cl and 25.3kg hour, obtain uniform mixture.After the cooling, add predetermined amount benzene, obtain generating the homogeneous solution of mixture.Under predetermined temperature, slowly Dropwise 5 1.5kg sesquialter ethylaluminium chloride then stirred 1 hour.With normal hexane repeated washing reaction mixture, obtain the solid catalyst of 25kg.

Polymerization

In the presence of the catalyst component of above-mentioned preparation, with two placed in-line 0.6m ³Reactor carries out successive polymerization.The ingredient of solid catalyst, 31kg/ hour ethene and the hydrogen that add continuously the aluminium diethyl monochloride, 1.88g/ hour of 70kg/ hour normal hexane, 3.63g/ hour in first polymerizer, and successive polymerization under 90 ℃ temperature, keeping the mol ratio of hydrogen/ethene simultaneously in gas phase is 2.8.Be added in the polymer paste for preparing in first polymerizer in second polymerizer continuously, also add 47kg/ hour normal hexane and 27.0kg/ hour ethene, successive polymerization under 65 ℃ temperature, keeping the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene respectively simultaneously in gas phase is 0.03 and 0.08.

Slurry is taken out from second polymerizer.After solid-liquid separates in centrifuge separator, the dry then polymkeric substance that obtains thus.Mediate polymkeric substance that generates and the tablets press granulation of under predetermined condition, using Φ 90mm.Pellet is made pipe and tested its physicals.The results are shown in Table 1.

Embodiment 2

Repeat the method for embodiment 1, except using triethyl aluminum as promotor.Successive polymerization in first polymerizer, keeping the mol ratio of hydrogen/ethene simultaneously in gas phase is 2.0.Successive polymerization in second polymerizer, keeping the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene respectively simultaneously in gas phase is 0.03 and 0.12, and the feed molar ratio that keeps joining the ethene of fs and joining the ethene of subordinate phase is 55/45.

Comparative example 1

Repeat the method for embodiment 1, except continuous polymer in second polymerizer, keeping the mol ratio of hydrogen/ethene respectively simultaneously in gas phase is 0.08.

Comparative example 2

Repeat the method for embodiment 1,, in gas phase, keep the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene to be 0.05 respectively simultaneously except successive polymerization in second polymerizer.

Comparative example 3

Repeat the method for embodiment 1, except successive polymerization in first polymerizer, the mol ratio of setting hydrogen/ethene simultaneously in gas phase is 6; And to keep the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene in gas phase respectively be 0.01 and 0.06, and the feed molar ratio that keeps joining the ethene of fs and joining the ethene of subordinate phase is 46/54.

Comparative example 4

Repeat the method for embodiment 1, except successive polymerization in second polymerizer, simultaneously keeping the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene respectively in gas phase is 0.01 and 0.13, and the feed molar ratio that keeps joining the ethene of fs and joining the ethene of subordinate phase is 55/45.

Comparative example 5

Repeat the method for comparative example 1, except successive polymerization in first polymerizer, keeping the mol ratio of 1-butylene/ethene simultaneously in gas phase is 0.01; Successive polymerization in second polymerizer, keeping the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene respectively simultaneously in gas phase is 0.05 and 0.065.

Comparative example 6

Repeat the method for embodiment 2, except successive polymerization in first polymerizer, keeping the mol ratio of 1-butylene/ethene simultaneously in gas phase is 0.03; Successive polymerization in second polymerizer, keeping the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene respectively simultaneously in gas phase is 0.012 and 0.04; And the feed molar ratio of setting the ethene join the fs and joining the ethene of subordinate phase is 54/46.

Comparative example 7

Repeat the method for embodiment 1, except successive polymerization in first polymerizer, the mol ratio of setting hydrogen/ethene simultaneously in gas phase is 7; Successive polymerization in second polymerizer, keeping the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene respectively simultaneously in gas phase is 0.01 and 0.14.

Comparative example 8

Repeat the method for embodiment 1, except successive polymerization in first polymerizer, the mol ratio of setting hydrogen/ethene simultaneously in gas phase is 4.5; Successive polymerization in second polymerizer, keeping the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene respectively simultaneously in gas phase is 0.15 and 0.04; And the feed molar ratio of setting the ethene join the fs and joining the ethene of subordinate phase is 35/65.

Comparative example 9

Repeat the method for embodiment 1, except successive polymerization in first polymerizer, the mol ratio of setting hydrogen/ethene simultaneously in gas phase is 5.5; Successive polymerization in second polymerizer, keeping the mol ratio of hydrogen/ethene and the mol ratio of 1-butylene/ethene respectively simultaneously in gas phase is 0.005 and 0.15; And the feed molar ratio of setting the ethene join the fs and joining the ethene of subordinate phase is 25/75.

Can be obviously as can be known from the embodiment 1 and 2 of table 1, when making in WH, TL, TH and Parameter H the scope in claim 1 by control MFR5, velocity ratio FR and density (ρ), the pipe of being made by the polyvinyl resin of gained can not cause brittle crack at least 165 hours in the statics of fluids test of the hoop stress of 80 ℃ 5.5Mpa, thereby satisfied desired performance among the ISO4427.In addition, after carrying out 10000 hours, this experiment do not observe brittle rupture yet.Olsen hardness is 1100MPa, simultaneously pipe do not rupture (NB) after the Izod Impact Test.As mentioned above, the present invention can make the pipe that can satisfy any one requirement in rigidity, shock-resistance and the long durability.

Shown in comparative example 1, when MFR5 surpasses the scope of claim 1, in the statics of fluids test brittle rupture appears, and shock strength is 15kJ/m in the Izod Impact Test ², deficiency.

Shown in comparative example 2, when density (ρ) surpasses the scope of claim 1, in the statics of fluids test brittle rupture appears.On the other hand, when density (ρ) was lower than the scope of claim 1, shown in comparative example 4, statics of fluids was tested rupture time less than 165 hours, thereby can not satisfy the requirement of ISO 4427.Shock strength is 12kJ/m in the Izod Impact Test ², deficiency.

Shown in comparative example 8, when flow rate F R was lower than the scope of claim 1, WH, Parameter H and TH brittle rupture occurred in the statics of fluids test outside claim 1 time.

In addition, the Izod Impact Test shows that shock strength is 13kJ/m ², deficiency.On the other hand, when flow rate F R surpassed the scope of claim 1, WH was outside claim 1 time, and the Izod shock strength is low to moderate 5kJ/m ²

When WH and Parameter H not during scope, shown in comparative example 3 in claim 1; When TL is outside claim 1, shown in comparative example 5; Or when TH is outside the scope that power requires, shown in comparative example 6, in the statics of fluids test brittle rupture appears.Comparative example 3 also shows the shock strength deficiency.

When Parameter H not during the scope in claim 1, shown in comparative example 7, in the statics of fluids test brittle rupture appears.In the Izod Impact Test, the Izod shock strength is 15kJ/m ²

As comparative example 1,2,3, shown in 5,6 and 8, when the polyvinyl resin of gained does not have following this performance, promptly when under 80 ℃ constant stress, carrying out the environmental stress cracking test, rupture time is 20 hours or longer under the 6MPa initial load, and rupture time is 80 hours or when longer under the 4MPa initial load, observes brittle rupture in 10000 hours in every pipe in the statics of fluids test.

Table 1

	MFR5	FR	Density	WH	H	TL	TH	The Izod shock strength	Modulus in flexure	ESC6	ESC4	Creep 1	Creep 1
															The g/10 branch		g/cm 3	％	×10 -8 dyn/cm 2	℃	℃	kJ/m 2	MPa	Hour	Hour
Embodiment 1	0.26	100	0.951	42	1.79	99.7	96.0	NB	1,100	100	＞300	○	Do not observe
														Embodiment 2	0.36	120	0.950	40	1.81	99.4	94.9	NB	1,000	200	＞300	○	Do not observe
														Comparative Examples 1	0.52	80	0.951	42	1.90	99.6	95.9	15	1,100	12	40	○	Observe
Comparative Examples 2	0.28	95	0.955	42	1.88	99.7	96.4	NB	1,200	20	40	○	Observe
														Comparative Examples 3	0.34	81	0.951	50	2.04	99.5	96.4	17	1,100	25	60	○	Observe
Comparative Examples 4	0.22	110	0.945	40	1.87	99.5	96.4	12	900	130	300	×	Do not observe
														Comparative Examples 5	0.23	100	0.952	42	1.83	98.7	95.8	NB	1,100	17	35	○	Observe
Comparative Examples 6	0.27	91	0.952	41	1.84	99.4	96.7	NB	1,100	14	30	○	Observe
														Comparative Examples 7	0.42	126	0.949	42	2.10	99.2	94.5	15	1,000	90	＞300	○	Observe
Comparative Examples 8	0.75	62	0.952	60	2.27	99.4	96.7	13	1,100	5	30	○	Observe
														Comparative Examples 9	0.48	210	0.952	30	1.85	99.4	94.7	5	1,100	70	250	○	Observe

ESCR under the incipient extension load of ESC6:6MPa.

ESCR under the incipient extension load of ESC4:4MPa.

Creep 1: the creep test under 80 ℃ and 5.5MPa is weather resistance that 165 hours or longer polyethylene are evaluated as " zero ", be evaluated as " * " that does not have.

Creep 2: the creep test under 80 ℃ and 5.5MPa is evaluated as " observing " to the polyethylene of generation brittle rupture in 10000 hours, be evaluated as " not the observing " that does not have.

Commercial Application

The invention provides good pipe and the connector of rigidity, resistance to impact and long durability under stress (environmental stress resistance of pipe, long-term hydrostatics intensity and anti-slow breach hyperplasia (SCG)). Particularly, with having when surperficial tool test block jaggy carries out the environmental stress cracking test under 80 ℃ constant stress, rupture time is 20 hours or longer under the 6MPa initial load, rupture time is 80 hours or when longer under the 4MPa initial load, does not observe brittle fracture in 10000 hours in the hydrostatics test.

Claims (3)

1, a kind ofly leave linear polyethylene preparation and that have following physicals (1)-(6) at ziegler natta catalyst:

(1) be the 0.20-0.50g/10 branch at the melt speed MFR that under 190 ℃, records under the 5.00kg testing load;

(2) throughput ratio FR is 65-130,

(3) density p is 0.948-0.952g/cm ³,

(4) be 1.85 * 10 by following equation (I) relaxation parameter H expression and that can obtain by stress test ^-8Dyne/cm ²Or lower,

$H=-E\left({10}^3\right)\frac{\mathrm{LogE}\left({10}^3\right)-\mathrm{LogE}\left({10}^0\right)}{\mathrm{Log}{10}^3-\mathrm{Log}{10}^0}$

Loose modulus when wherein, E (ι) shows time ι.

(5) in whole all eluting temperature zones, the integration of the amount of every kind of high molecular part calculating in each many eluting temperatures district, for in the ratio WH of total elution amount, be 39-45% weight, the amount of described every kind of high molecular part is measured by the intersection classification TREF-SEC that comprises temperature rise elution fractionation TREF and size exclusion chromatography, SEC.

The peak temperature TH of the elution curve of the amount of every kind of high molecular part (6) calculating in each many eluting temperatures district is 96.0 ℃ or lower, and the amount of described every kind of high molecular part is measured by the intersection classification TREF-SEC that comprises temperature rise elution fractionation TREF and size exclusion chromatography, SEC;

With

The peak temperature TH of the elution curve of the amount of every kind of low molecular weight part calculating in each many eluting temperatures district is 99.2 ℃ or higher, and the amount of described every kind of low molecular weight part is measured by intersection classification TREF-SEC.

2, pipe and the web member of making by the polyvinyl resin of claim 1.

3, the pipe of claim 2 or web member, it has following performance: be used in when carrying out the environmental stress cracking test under 80 ℃ the constant stress, rupture time is 20 hours or longer under the 6MPa initial load, and rupture time is 80 hours or when longer under the 4MPa initial load.