WO1998055540A1 - Procede servant a preparer des particules poreuses de polyolefines - Google Patents

Procede servant a preparer des particules poreuses de polyolefines Download PDF

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Publication number
WO1998055540A1
WO1998055540A1 PCT/NL1998/000321 NL9800321W WO9855540A1 WO 1998055540 A1 WO1998055540 A1 WO 1998055540A1 NL 9800321 W NL9800321 W NL 9800321W WO 9855540 A1 WO9855540 A1 WO 9855540A1
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Prior art keywords
polyolefin
particles
solvent
process according
temperature
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PCT/NL1998/000321
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English (en)
Inventor
Rudolf Lucien Scherrenberg
Harold Jan Smelt
Roelof Franciscus Gerardus Maria De Vos
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Dsm N.V.
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Publication date
Application filed by Dsm N.V. filed Critical Dsm N.V.
Priority to JP50213799A priority Critical patent/JP2002503281A/ja
Priority to AU80394/98A priority patent/AU8039498A/en
Priority to KR19997011417A priority patent/KR20010013416A/fr
Priority to EP98928644A priority patent/EP0986602A1/fr
Publication of WO1998055540A1 publication Critical patent/WO1998055540A1/fr

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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
    • C08J9/28—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
    • 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
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/04—Foams characterised by the foaming process characterised by the elimination of a liquid or solid component, e.g. precipitation, leaching out, evaporation
    • C08J2201/052—Inducing phase separation by thermal treatment, e.g. cooling a solution
    • 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
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/04—Foams characterised by the foaming process characterised by the elimination of a liquid or solid component, e.g. precipitation, leaching out, evaporation
    • C08J2201/054—Precipitating the polymer by adding a non-solvent or a different solvent
    • C08J2201/0542—Precipitating the polymer by adding a non-solvent or a different solvent from an organic solvent-based polymer composition
    • 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

Definitions

  • the invention relates to a process for preparing porous polyolefin particles.
  • the invention's aim is to provide a process for preparing porous polyolefin particles with which the aforementioned drawback is entirely or partly eliminated. This aim is achieved because the process comprises the following steps:
  • the process according to the invention moreover involves a smaller risk of the porous polyolefin particles prepared containing remains of one or more of the liquids.
  • An advantage of the process of the present invention is that the dimensions of the porous polyolefin particles are better controllable. Another advantage is that the dimensions of the porous polyolefin particles prepared show a smaller spread than in the state of the art.
  • the porous polyolefin particles obtained by using the process according to the present invention can be prepared using as starting materials a wide variety of polyolefins. Homopolymers are suitable, but so are copolymers .
  • the term ' copolymers ' is here and hereafter understood to mean polymers composed of two or more different monomers .
  • the monomers to be used may be ⁇ -olefins (such as ethylene, propylene or other ⁇ - olefins with 4-12 C atoms) .
  • the monomer may also be of a polar nature, such as for instance vinyl acetate.
  • the advantage of a vinyl acetate as a comonomer is that the porous particle made thereof is better capable of absorbing polar substances.
  • the concentration of polar monomer, for example vinyl acetate in EVA (ethylene- vinyl acetate copolymer) , suitable for the preparation of porous particles, is at most 25 wt.% relative to the total amount of polymer. In the context of the invention it is also possible to use mixtures of different polyolefins.
  • the polyolefins that can be used may be both freshly prepared polyolefins and polyolefins obtained after upgrading of used materials, for example in the framework of recycling, polyolefins collected as production rejects and production waste, contaminated polyolefins and polyolefins that do not meet previously specified product requirements, i.e. off-spec products. It is important that the polyolefins are soluble at a particular temperature and that the polyolefin is crystallizable, so that solid, porous structures are formed in the cooling step. It is however not necessary for the polyolefin to be completely (100%) crystallizable.
  • Polyolefins that are suitable for preparing the porous polyolefin particles according to the invention are for example polyethylene, polypropylene, polybutylene, poly (4-methyl-1-pentene) , polycyclohexylethylene .
  • the polyethylene may for example have been prepared via processes known per se, including solution, slurry, gas-phase and high-pressure processes.
  • the polyethylene ' s density may vary between 880 and 965 kg/m 3 .
  • Ultra-high-molecular-weight polyethylene UHMWPE
  • HDPE high- density polyethylene
  • LLDPE linear low-density polyethylene
  • LDPE low-density polyethylene
  • VLDPE very-low-density polyethylene
  • ULDPE ultra-low- density polyethylene
  • LLDPE' is understood to be a substantially linear homopolymer or copolymer of ethylene and one or more ⁇ -olefins with 3-12 C atoms and optionally one or more non-conjugated dienes .
  • Particularly suitable ⁇ - olefins are propylene, 1-butene, 1-hexene, 4- methylpentene-1 and l-octene.
  • Suitable dienes are for example 1, 7-octadiene and 1,9 decadiene.
  • LLDPE mainly has short side chains of 1 to 10 C atoms and considerably shorter side chains than LDPE.
  • LDPE is a highly branched polyethylene.
  • LDPE use can be made of for example polyethylene that is produced in the usual way in a high-pressure process with the aid of one or more radical initiators . This high-pressure process can take place in an autoclave or in a tubular reactor. LDPE has a density lower than 935 kg/m 3 . Mixtures with EVA are also very suitable.
  • this polyolefin preferably has a DSC crystallization peak with a width of at least 5°C.
  • the width of the crystallization peak is at least 10°C and in particular at least 15°C. This width is the peakwidth measured at half of the height of the crystallization peak in the DSC curve.
  • these polyolefins When a mixture of polyolefins is used, these polyolefins must preferably have different crystallization peak temperatures. Preferably such a difference in crystallization temperatures is 5°C or more.
  • the amount of polyolefin with a higher crystallization temperature is at least 0.1 wt . % relative to the polyolefin with a lower crystallization temperature, preferably between 1 and 5 w . % .
  • the polyolefins or mixtures of polyolefins show a fast crystallisation behaviour upon cooling of the polyolefin solution. Crystallisation behaviour is considered to be fast, when the maximum crystallisation peak lies within 5 °C of the start of crystallisation in a DSC experiment as indicated hereinafter.
  • a polyolefin 's crystallization temperature and thermal behaviour can be determined with the aid of the Differential Scanning Calorimetry (DSC) technique.
  • DSC Differential Scanning Calorimetry
  • a substance or a mixture of substances is heated or cooled under controlled conditions in a controlled atmosphere while the difference in temperature between the substance and a reference material (as a result of energy changes in the substance) is continuously measured.
  • a transition (such as melting or crystallization) is marked by the substance or the mixture absorbing or releasing energy, which results in a corresponding endothermal or exothermal peak in the DSC curve.
  • the curve may contain more than one peak.
  • a DSC measurement can be carried out both on the polyolefin and on the solution of the polyolefin in the solvent .
  • the polyolefin or the polyolefin solution is heated at 5°C/min. to 200°C (first heating curve) ; this is followed by cooling by 5°C/min. to -50°C (cooling curve) . Then a second heating curve is recorded at a heating rate of 5°C/min.
  • the polyolefin 's melting and crystallization behaviour is characterized on the basis of the latter two curves.
  • the temperature at which the (DSC) crystallization curve (the cooling curve) deviates 1% from the base line is taken as the temperature at which crystallization starts, the percentage being relative to the height of the maximum peak.
  • the width of the crystallization peak is defined as the width at half height at the temperature at which the cooling curve shows a maximum.
  • a nucleating agent is an ingredient which has an ability to stimulate the formation of polyolefin crystallites during the cooling of the polyolefin solution and does not dissolved in the polyolefin solution during the process of the invention.
  • the polymer particle is dried at a temperature at which a substantial portion of the crystallization of the polyolefin has already taken place.
  • the drying temperature is below the temperature in the DSC thermogram at which 50% of the polyolefin 's total heat of crystallization has been released.
  • the heat of crystallization is represented by the surface area beneath the cooling curve in the DSC thermogram.
  • the drying temperature is lower than the temperature at which 75% of the total heat of cystallization has been released. This ensures that the porous polyolefin' s structure remains optimally intact during the drying process.
  • the process according to the invention is carried out as follows.
  • the polyolefin or the mixture of polyolefins is first dissolved in a solvent .
  • Various organic liquids can be used as the solvent .
  • the type of solvent to be used will to a great extent depend on the solvent's ability to dissolve the polyolefin.
  • Suitable organic solvents for use in the process of the present invention are for example compounds from the series of the n-alkanes, i-alkanes, cycloalkanes, polycyclic compounds with two or more cyclic structures, alkenes, cycloalkenes, aromatic compounds which may or may not be substituted, chlorinated hydrocarbons, decalin, tetralin or paraffin oil.
  • the compounds may be both substituted and unsubstituted.
  • the substituent group may consist of both C and H atoms alone, and of C, H and/or hetero atoms.
  • the substituent group preferably has 3-100 C atoms.
  • polyethylene is used as the polyolefin use is in particular made of a cycloalkane or an alkane, more in particular of cyclohexane, boiling-point spirit, hexane, heptane or octane or mixtures thereof.
  • a polar solvent is used for polar olefins.
  • the polyolefin can optionally be dissolved in the solvent with simultaneous heating. If necessary, the dissolving can be accelerated by means of dynamic or static mixing. In some cases, depending on the type of solvent chosen, it may be advantageous to work at elevated pressure, which enables dissolution at a temperature above the solvent ' s atmospheric boiling point. A person skilled in the art will easily be able to determine whether working at elevated pressure will be advantageous .
  • the temperature at which the polyolefin is dissolved is not critical as long as the polyolefin dissolves. A person skilled in the art will be able to easily determine this, too. Usually the dissolution temperature will lie between 40 and 200°C.
  • the dissolution temperature lies between 70 and 180 °C.
  • the polyolefin is effectively dissolved in the solvent.
  • the polyolefin solution that is formed contains between approx. 0.1 and 50 wt.%, preferably between 15 and 35 wt.%, polyolefin. This obviates the need for interim removal through evaporation of part of the solvent.
  • concentrations of > 50 wt.% it becomes difficult to stir the polyolefin solution; at low concentrations the process becomes less interesting from an economic viewpoint .
  • the polyolefin solution obtained and a non- solvent are dispersed in one another, optionally with stirring or a different form of dynamic or static mixing.
  • the order in which the non-solvent and the polyolefin solution are added to one another for dispersion is not critical, provided the non-solvent is the continuous phase in the dispersion obtained.
  • the non-solvent is a compound in which the polyolefin does not dissolve.
  • the amount of non-solvent to be used is not critical, provided that the non-solvent remains the continuous phase in the dispersion obtained.
  • the polyolefin solution : non- solvent volume ratio may vary between 10:1 and 1:10; preferably this ratio varies between 5:1 and 1:5. Most preferably the ratio varies between 1:1 and 1:3.
  • the non-solvent is a polar or an apolar compound, depending on the polyolefin 1 s polarity.
  • a polar non-solvent is very suitable for use with a polyolefin that dissolves in an apolar solvent.
  • Polar compounds that are suitable for use as non-solvent are for example water or a compound from the group of the organic or inorganic acids, ketones or alcohols. Preferably water, acetone, methanol or ethanol are used and more preferably water is used. Mixtures of these compounds are also suitable .
  • a multi-phase system is formed, a 'multi-phase 1 system being understood to be a system that consists of at least two phases, one of which contains the polyolefin: the polyolefin- containing phase.
  • the temperature of the polyolefin solution and the non-solvent must lie above the temperature at which the polyolefin in the polyolefin solution starts to cystallize. Preferably the temperature lies at least 15°C above the temperature at which cystallization starts.
  • the surfactant concentration is preferably between 10 ppm and 5 wt.%, more preferably between 100 ppm and l wt.%. If the surfactant concentration is too low, the droplets of polyolefin solution may show too great a tendency to aggregate. If the surfactant concentration is too high, very small particles may be formed.
  • porous polyolefin particles with dimensions from 0.01 up to approximately 12 mm can be obtained. An average person skilled in the art will easily be able to experimentally determine the most desirable concentration.
  • the surfactant may be an anionic, cationic, non-ionic or amphoteric tenside.
  • Suitable surfactants are for example compounds from the group of the alkane sulphonates, alkylbenzene sulphonates, fatty alcohol sulphonates, alkylammoniu compounds, tensides of the betaine type, alkyl polyglycol ethers, ethoxylated fatty amines, Tween ® , Span ® and alkyl phenol ethoxylates .
  • an anti-foaming and/or defoaming agent can be added.
  • a combination of anti- foaming and/or defoaming agents is also possible.
  • These anti-foaming and/or defoaming agents can be added in different steps of the process, but preferably before the dispersion step.
  • a portion of the solvent can optionally be evaporated from the multiphase system formed. Whether evaporation is necessary or not will depend on the polyolefin and the solvent used as the starting materials and the initial polyolefin concentration. The amount of solvent to be evaporated depends on the polyolefin solution's concentration. The lower the concentration, the greater the amount that can be evaporated.
  • the solvent, the non-solvent and the polyolefin (mixture) can also be combined in a single step. This mixture is then stirred, optionally with heating, until the polyolefin has dissolved and the polyolefin solution has been dispersed in the non- solvent. The resulting multi-phase system is subsequently cooled.
  • step 3 The cooling of the multi-phase system in the process according to the invention (step 3) takes place at a rate between 0.05 and 10°C/minute, preferably at a rate between 0.1 and 5°C/min and in particular between 0.2 and 2°C/min. This cooling is in principle continued until more than 50% of the total heat of cystallization of the polyolefin in the polyolefin solution has been released.
  • the temperature corresponding to this point can, as already described above, be determined with the aid of the DSC technique.
  • the cooling is preferably continued to below 40°C.
  • the cooling is preferably continued to below 70°C.
  • the dispersion must be retained during the cooling of the multi-phase system, which can be realized with the aid of stirrers or by means of static or dynamic mixing.
  • the particle size can also be controlled depending on the type of stirrer and the speed. The higher the amount of energy supplied, or the more vigorous the stirring (with the same type of stirrer) , the smaller the porous polyolefin particles will be. And, vice versa, the lower the amount of energy supplied, or the slower the stirring, the larger the particles will be.
  • the polyolefin-containing particles are separated from the multi-phase system (step 4).
  • This separation can take place in a manner known to a person skilled in the art. Suitable techniques are for example vacuum filtration, centrifugation and/or filtration pressing. Preferably use is made of filtration under the influence of gravity.
  • the separated polyolefin particles which still contain solvent and optionally non-solvent, are dried. Drying may take place to any desired degree of solvent and non-solvent removal. The execution of this drying process largely determines whether or not the polyolefin particles obtained will retain their porosity.
  • the drying process for obtaining porous polyolefin particles can be carried out in various ways, both as such or in combination with each other.
  • the drying can for example take place under reduced pressure, the polyolefin-containing particles can be stripped with a gas or vapour or the polyolefin- containing particles can be dielectrically dried (for example with the aid of microwave or RF (radio- frequency) drying as for example described in
  • Suitable gases for use in the stripping process and optionally during drying under reduced pressure are for example air, nitrogen, helium, carbon dioxide and methane.
  • nitrogen is used as the stripping gas.
  • the drying also under reduced pressure, preferably takes place under conditions such that the partial pressure of the solvent in the vapour phase is less than 50%, but more preferably less than 20%, of the solvent's normal vapour pressure at the drying temperature .
  • the temperature during the drying of the polyolefin particles is initially preferably below the temperature at which 75% of the total heat of cystallization has been released. This temperature can be determined with the aid of DSC.
  • the drying temperature may be increased higher as the amount of solvent decreases and as a result the polyolefin 's concentration increases. Especially the removal of the non-solvent may need a higher drying temperature to be effectively carried out.
  • the drying is preferably initially carried out at a temperature below 30°C; preferably this temperature is below 20°C.
  • the drying preferably takes place under conditions such as to prevent disintegration of the particle structure as much as possible (for example by capillary and mechanical forces) . Disintegration of the particle structure will cause the particle size distribution to increase.
  • the particle size distribution will hereinafter be quantified by the degree of dispersion (DOD) .
  • DOD degree of dispersion
  • non-ionic tensides as surfactants.
  • Typical examples of the specific non-ionic tensides are tensides from the group comprising alkyl polyglycol ethers, ethoxylated fatty amines or alkyl phenol ethoxylates .
  • the particle size distribution is quantified by the degree of dispersion (DOD) , as determined according to DIN 66 165.
  • DOD degree of dispersion
  • An advantage of the porous polyolefin particles that have a small DOD is that their flow behaviour has been greatly improved and that the porous polyolefin particles thus prepared can be very accurately, and in a reproducible manner, dosed to processing machines like extruders .
  • the particles obtained with the process in which the specific non- ionic tensides are applied according to this invention have a DOD of ⁇ 0.4. Particles with such a small DOD are not yet known to date. The invention therefore also relates to these porous polyolefin particles.
  • porous polyolefin particles according to the invention have:
  • E ⁇ A is the effective loadability of the polyolefin particle with an absorption agent
  • m A the absorbed weight of the absorption agent
  • ⁇ A the absorption agent's density
  • m P0 the weight of the porous polyolefin particles before absorption of the absorption agent
  • p P0 the polyolefin' s density
  • porous polyolefin particles have an accessible open pore structure and a narrow particle size distribution. These particles have a high effective loadability, a short absorption time, are suitable for use as concentrate and show good flow and dosing properties.
  • a suitable absorption agent for determining the effective loadability is Atmer ® 163, an ethoxylated amine .
  • the particles ' porosity ⁇ is determined with the aid of mercury (Hg) porosimetry according to ASTM- standard D4284-83 using an Autopore II 9220 from Micrometrics (USA) .
  • the porosity is determined by measuring the volume of Hg that is forced into the pores at various pressures . The measurement starts at a pressure 3kPa. At this low pressure the open spaces between the polyolefin particles are ' (inter) ' filled with Hg. Subsequently the pressure is continuously increased upto about 400 MPa, resulting in intrusion of Hg into the polyolefins particles ' (intra) ' . At high pressures some compression of the polymeric material might occur.
  • the difference between the volume of Hg in the dilatometer before and after pressurization is a measure for the porosity of the polyolefin.
  • the porosity is calculated by dividing the intruded-Hg- volume determined at the pressure at which 85% of the pores are filled minus the intruded-Hg-volume determined at a pressure at which 15% of the pores are filled by the total volume of the porous particle.
  • the total volume of the porous particle is calculated by summarizing the intruded Hg-volume as specified above with the weight of the polymer sample divided by its density.
  • the particles porosity varies between 5 and 85%.
  • the porosity is more than 25%, more preferably more than 35%.
  • a high porosity results in a wide range of possible applications for the porous polyolefin particle.
  • the pore diameter varies between 0.01 and 100 ⁇ m.
  • a weighed amount of porous particles is introduced into a beaker with a stirring bar at room temperature.
  • a certain amount of absorption agent such as Atmer ® 163, is added with stirring until the porous particles no longer absorb any absorption agent. This is the case when a film of liquid and/or droplets of Atmer is/are formed on the beaker's wall which has/have still not disappeared after 5 minutes.
  • the porous polyolefin particles are then considered to be saturated with the absorption agent.
  • the amount of absorption agent absorbed can be determined.
  • E iA is > 95%, preferably > 99%.
  • a major advantage of the porous polyolefin particles according to the invention is that the particles can absorb a large amount of absorption agent and that, moreover, this absorption process also proceeds rapidly.
  • the absorption time of the porous polyolefin particles according to the invention is at most 10 minutes.
  • the absorption time (t a ) is determined by filling a beaker with DOW Corning 200 ® Fluid, viscosity 1 cSt at R, density 820 kg/m 3 .
  • the porous polyolefin particles are placed on top of this liquid.
  • the absorption time is the amount of time the particles require to sink to the bottom of the beaker. All this takes place at room temperature .
  • the DOD is determined using a non-sieved polyolefin, by means of an experiment for determining the particle size.
  • the particle size is determined according to standard DIN 66 165.
  • the DOD is defined as :
  • the porous polyolefin particles of the invention have a DOD of ⁇ 0.4.
  • the DOD is ⁇ 0.2. More preferably the DOD is ⁇ 0.15.
  • the size of the porous polyolefin particles according to the present invention usually varies between 0.5 and 12 mm. Particles that are smaller than 0.5 mm and larger than 12 mm are also possible, but the dosing properties and flow properties are then less favourable .
  • FIG. 1 a few electron microscopy (SEM) photos of porous polyolefin particles obtained by using the process according to the invention are shown in Figures 1-4.
  • Figure 5 shows porous polyolefin particles with a narrow DOD
  • figure 6 shows polyolefin particles with a wide DOD.
  • the porous polyolefin particles prepared with the process according to the invention are suitable for different applications, for example as concentrates, absorbents or carriers of substances that are to be released slowly and/or in a controlled manner .
  • the additive can be directly absorbed. If the additive is in a solid form, it can be melted, dissolved or dispersed in a suitable liquid before being brought into contact with the porous polyolefin particle.
  • the absorption of additives in the porous polyolefin particle can be effected according to known techniques.
  • a suitable technique is for example to dose the additive to the porous polyolefin particle in a powder mixer .
  • a concentrate is often mixed with another polymer, for example a polyolefin, in an extruder so that the additive is homogeneously distributed in the polymer.
  • the porous polyolefin particle (prepared according to the process of this invention) is eminently suitable for mixing with another polymer, for example a polyolefin, in mixing equipment, such as for example an extruder. This is because the porous particle has a balanced mechanical stability. In a simple powder mixer the porous particle's structure will remain almost entirely intact, so that little or no dust is formed during the forming of the concentrate.
  • porous polyolefin particles in another application of these porous polyolefin particles according to the invention the particles can be used to effect a slow release of an active substance.
  • the active substance is first absorbed by the porous polyolefin particle, after which the substance in question is slowly released.
  • Medicines, fragrances, insecticides, pheromones and fertilizers can be mentioned as examples of active substances .
  • the porous polyolefin particles are also suitable for (selectively) absorbing certain substances. Examples are the absorption of stench components, leaked and/or spilled liquids or the purification of contaminated water streams, in which process the porous polyolefin particle absorbs the contaminants.
  • polar, porous polyolefin particles such as EVAs, ensures that the particles are well capable of absorbing polar substances.
  • the density, d was determined according to ASTM standard D792-66.
  • the melt index, MI was determined according to ASTM standard D1238, condition E.
  • the DSC measurements were carried out using a Perkin-Elmer DSC-7.
  • the temperature and energy calibrations were carried out on the basis of the melting of indium and lead.
  • the temperature measurement during the cooling is controlled on the basis of the solid-solid transition of 4, 4 ' -azoxy-anisole. Heating and cooling rates of 5°C/min. were used during the measurement .
  • Polyolefin particles were prepared according to Example I. 0.4 grams of isotridecyl alcohol polyglycol ether with 8 ethylene oxide units was used as the non-ionic surfactant.
  • Example III Example II was repeated using 0.6 g of non- ionic surfactant. Firm, predominantly spherical polyolefin particles were obtained. Comparison of Examples II and III shows that the porous polyethylene particles become smaller when the concentration of non-ionic surfactant is increased.
  • Example I The polyolefin particles were separated with the aid of a sieve. These particles were dried in a fluid bed with a nitrogen flow of 40°C. A higher concentration of polyolefin in the polyolefin solution results in a porous polyolefin particle with a lower porosity.
  • Example VI In a vessel 85 g of LDPE (with a density of 918 kg/m 3 and an MI of 8 dg/min.) was dissolved in 300 g of heptane at 95°C with heptane reflux. 0.85 grams of LLDPE (with a density of 936 kg/m 3 and an MI of 4.4 dg/min.) was added to the solution. Next, 750 grams of water of 74°C in which 0.6 g of non-ionic surfactant, Cn-oxo alcohol polyglycol ether with 7 ethylene oxide units, had been dissolved was dosed to this solution. The rest of the preparation was carried out as in Example I .
  • Example VI Example VI
  • the stirring configuration consisted of MIG stirrers combined with 4 baffles.
  • the pressure increased because the heptane/water mixture reached its azeotropic boiling point.
  • the mixture was cooled at a rate of approx. l°C/min.
  • the mixture was poured onto a sieve to separate the water phase.
  • spherical polyolefin particles with a diameter of 3 to 4 mm remained.
  • These particles were subsequently dried in a continuously vibrated fluid bed with nitrogen circulation, the ingoing fluidizing gas having a temperature of 40-60°C.
  • the bed temperature increased slowly from 5 to 60°C.
  • the porous polyolefin particles showed comparable characteristics as the particles made in Example I.
  • Example VI was repeated, but now 37 kg of cyclohexane was used.
  • the particles were dried in a tray drier, inertized with nitrogen, at a pressure of ⁇ 10 kPa and a plate temperature of 20 °C. After about 48 hours the plate temperature was increased to 50 °C.
  • Example VIII
  • n-heptane 60 g of LDPE with a density of 918 kg/m 3 and an MI of 8 dg/min.
  • 0.6 g of LLDPE with a density of 936 kg/m 3 and an MI of 4.4 dg/min. and a soap solution were introduced into a vessel.
  • the soap solution consisted of 580 g of demineralized water and 0.40 g of Cn-oxo alcohol polyglycol ether with 7 ethylene oxide units.
  • the mixture obtained was inertized with nitrogen and heated to 95°C with stirring with the aid of a pitched-blade stirrer (200 W/m 3 ) . After the stirrer had been stopped, complete phase separation was awaited.
  • the two-phase system was subsequently cooled with stirring to 25°C at l°C/min. After the polyolefin particles had been separated with the aid of sieve, firm, predominantly spherical particles were obtained. These particles were dried in a vacuum stove at room temperature and a pressure of ⁇ 10 kPa.
  • Example VIII was repeated, only now the LDPE employed had a density of 932 kg/m 3 and an MI of 8 dg/min.
  • the particles formed were then separated from the water with the aid of a sieve.
  • Firm, predominantly spherical, wet polyolefin particles were obtained.
  • These particles were then dried in a fluid bed with the aid of a flow of nitrogen, the temperature of the drying gas being varied from 5 to 40°C. During the evaporation of the solvent the temperature of the product did not rise above 20 °C.
  • the porosity was 77%.
  • Porous polyolefin particles are formed which show a very broad particle size distribution (see figure 6) . Comparative Experiment B
  • n-heptane 52 grams LDPE with a density of 926 kg/m 3 and an MI of 4 dg/min
  • 0.6 gram di-ethylbenzylidene sorbitol the product NC-4 supplies by Mitsui Toatsu
  • a soap solution consisted of 580 gram of demineralized water and 0.4 gram of Cn-oxo alcohol poly glycolether with 7 ethylene-oxide units.
  • the mixture obtained was inertized with nitrogen and heated to 95°C with stirring with the aid of a pitched-blade stirrer (200 W/m 3 ) . After the stirrer had been stopped, complete phase separation was awaited.
  • the two-phase system was subsequently cooled with stirring to 25°C at l°C/min. After the polyolefin particles had been separated with the aid of sieve, firm, particled were obtained, that show a broad DOD. These particles were dried in a vacuum stove at room temperature and a pressure of ⁇ 10 kPa.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Medicinal Preparation (AREA)

Abstract

L'invention concerne un procédé servant à préparer des particules poreuses de polyoléfines. Ce procédé consiste à: (1) dissoudre au moins une polyoléfine cristallisable dans un solvant en l'absence d'agent de nucléation; (2) disperser la solution obtenue de polyoléfine dans un non-solvant en présence d'un tensioactif à une température supérieure à la température de cristallisation de la polyoléfine dans la solution de polyoléfine; (3) refroidir le système à phases multiples obtenu en l'agitant à une température située entre 0,05 et 10 °C/min jusqu'à une température inférieure à la température de cristallisation du polymère dans la solution de polymère, de manière à obtenir des particules solides de polyoléfine; (4) séparer les particules de polyoléfine; (5) sécher ces particules de polyoléfine. L'invention concerne également une particule poreuse de polyoléfine présentant une capacité de chargement extrêmement efficace et une répartition étroite de la dimension des particules.
PCT/NL1998/000321 1997-06-05 1998-06-02 Procede servant a preparer des particules poreuses de polyolefines WO1998055540A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP50213799A JP2002503281A (ja) 1997-06-05 1998-06-02 多孔性ポリオレフィン粒子の製造方法
AU80394/98A AU8039498A (en) 1997-06-05 1998-06-02 Process for preparing porous polyolefin particles
KR19997011417A KR20010013416A (fr) 1997-06-05 1998-06-02 Procede servant a preparer des particules poreuses de polyolefines
EP98928644A EP0986602A1 (fr) 1997-06-05 1998-06-02 Procede servant a preparer des particules poreuses de polyolefines

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
NL1006235 1997-06-05
NL1006235 1997-06-05
NL1007333 1997-10-23
NL1007333A NL1007333C1 (nl) 1997-06-05 1997-10-23 Werkwijze voor het bereiden van poreuze polyolefinedeeltjes.

Publications (1)

Publication Number Publication Date
WO1998055540A1 true WO1998055540A1 (fr) 1998-12-10

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PCT/NL1998/000321 WO1998055540A1 (fr) 1997-06-05 1998-06-02 Procede servant a preparer des particules poreuses de polyolefines

Country Status (7)

Country Link
EP (1) EP0986602A1 (fr)
JP (1) JP2002503281A (fr)
KR (1) KR20010013416A (fr)
CN (1) CN1265690A (fr)
AU (1) AU8039498A (fr)
NL (1) NL1007333C1 (fr)
WO (1) WO1998055540A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001016220A1 (fr) * 1999-08-30 2001-03-08 Sca Hygiene Products Ab Procede de production d'un materiau de mousse absorbant
DE10220038A1 (de) * 2002-05-04 2003-11-20 Membrana Gmbh Verfahren zur Herstellung geschäumter Polymerformkörper und geschäumter Polymerformkörper
EP1591473A1 (fr) * 2003-02-04 2005-11-02 Kao Corporation Particules poreuses et produits cosmetiques
WO2012010476A1 (fr) 2010-07-22 2012-01-26 Ineos Europe Ag Composition polymère
US8143472B1 (en) 1999-08-30 2012-03-27 Sca Hygiene Products Ab Absorbent structure in an absorbent article and a method of producing it
EP2474567A1 (fr) * 2009-09-04 2012-07-11 Sumitomo Seika Chemicals Co., Ltd. Particules sphériques de résine composite à base de polyoléfine, composition de revêtement et objet revêtu

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4606806B2 (ja) * 2004-08-03 2011-01-05 住友精化株式会社 ポリオレフィン系樹脂粒子の製造方法
KR20150143157A (ko) 2014-06-13 2015-12-23 주식회사 엘지화학 폴리머 입자의 제조방법
JP6892737B2 (ja) * 2016-02-16 2021-06-23 旭化成株式会社 ポリエチレン系パウダー及びその製造方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3308073A (en) * 1962-04-09 1967-03-07 Phillips Petroleum Co Porous polyolefin objects
EP0222718A2 (fr) * 1985-10-15 1987-05-20 Kjell G.C. Nilsson Particules macroporeuses
US4673695A (en) * 1985-10-08 1987-06-16 The United States Of America As Represented By The United States Department Of Energy Low density microcellular foams
EP0273582A1 (fr) * 1986-12-11 1988-07-06 Minnesota Mining And Manufacturing Company Matériaux microporeux comprenant un agent nucléant et leur méthode de préparation
GB2226320A (en) * 1988-12-23 1990-06-27 Ici Plc Non-attritive method for making polyethylene particles
WO1997020884A1 (fr) * 1995-12-06 1997-06-12 Dsm N.V. Procede de preparation de particules de polyolefines poreuses

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3308073A (en) * 1962-04-09 1967-03-07 Phillips Petroleum Co Porous polyolefin objects
US4673695A (en) * 1985-10-08 1987-06-16 The United States Of America As Represented By The United States Department Of Energy Low density microcellular foams
EP0222718A2 (fr) * 1985-10-15 1987-05-20 Kjell G.C. Nilsson Particules macroporeuses
EP0273582A1 (fr) * 1986-12-11 1988-07-06 Minnesota Mining And Manufacturing Company Matériaux microporeux comprenant un agent nucléant et leur méthode de préparation
GB2226320A (en) * 1988-12-23 1990-06-27 Ici Plc Non-attritive method for making polyethylene particles
WO1997020884A1 (fr) * 1995-12-06 1997-06-12 Dsm N.V. Procede de preparation de particules de polyolefines poreuses

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001016220A1 (fr) * 1999-08-30 2001-03-08 Sca Hygiene Products Ab Procede de production d'un materiau de mousse absorbant
US6774151B2 (en) 1999-08-30 2004-08-10 Sca Hygiene Products Ab Method of producing an absorbent foam material
US8143472B1 (en) 1999-08-30 2012-03-27 Sca Hygiene Products Ab Absorbent structure in an absorbent article and a method of producing it
DE10220038A1 (de) * 2002-05-04 2003-11-20 Membrana Gmbh Verfahren zur Herstellung geschäumter Polymerformkörper und geschäumter Polymerformkörper
US7429420B2 (en) 2002-05-04 2008-09-30 Membrana Gmbh Method for producing foamed polymer molded bodies and said foamed polymer molder bodies
EP1591473A1 (fr) * 2003-02-04 2005-11-02 Kao Corporation Particules poreuses et produits cosmetiques
EP1591473A4 (fr) * 2003-02-04 2006-06-14 Kao Corp Particules poreuses et produits cosmetiques
US8574600B2 (en) 2003-02-04 2013-11-05 Kao Corporation Porous particles and cosmetics
EP2474567A1 (fr) * 2009-09-04 2012-07-11 Sumitomo Seika Chemicals Co., Ltd. Particules sphériques de résine composite à base de polyoléfine, composition de revêtement et objet revêtu
EP2474567A4 (fr) * 2009-09-04 2013-12-11 Sumitomo Seika Chemicals Particules sphériques de résine composite à base de polyoléfine, composition de revêtement et objet revêtu
KR101734599B1 (ko) 2009-09-04 2017-05-11 스미또모 세이까 가부시키가이샤 폴리올레핀계 복합 수지 구상 입자, 도료 조성물 및 도장물
WO2012010476A1 (fr) 2010-07-22 2012-01-26 Ineos Europe Ag Composition polymère

Also Published As

Publication number Publication date
AU8039498A (en) 1998-12-21
KR20010013416A (fr) 2001-02-26
CN1265690A (zh) 2000-09-06
NL1007333C1 (nl) 1999-04-27
JP2002503281A (ja) 2002-01-29
EP0986602A1 (fr) 2000-03-22

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