FR2464970A1 - ETHYLENE-ALPHA-OLEFIN COPOLYMER POWDER FOR POWDER MOLDING - Google Patents

Abstract

THE INVENTION RELATES TO A POWDER OF ETHYLENE-ALPHA-OLEFINE COPOLYMER FOR POWDER MOLDING. THE COPOLYMER POWDER HAS A VOLUME WEIGHT OF BETWEEN 0.915 AND 0.945GCM; A CREEP INDEX OF 1 TO 80G10MN; A RATIO OF THE HIGH LOAD CREEP INDEX BELOW 21.6KG TO THE LOW LOAD CREEP INDEX UNDER 2.16KG WHICH IS NOT MORE THAN 30; AN APPARENT DENSITY OF 0.30 TO 0.50; AN ANGLE OF FRICTION OF 25-40 AND A SIZE DISTRIBUTION OF PARTICLES SUCH AS THE DIAMETER OF 50 OF THE PARTICLES OF THE POWDER IS BETWEEN 230 AND 350M AND THE DIAMETER OF THE PARTICLES AT LEAST 90 BY WEIGHT OF THE TOTAL POWDER IS INCLUDED BETWEEN 149 AND 500M.

Description

The present invention relates to a copolymer powder

  ethylene alpha-olefin for powder molding. More specifically, it relates to a suitable resin powder

  for use in a rotational molding process.

  The polyethylene powder is processed or used in powder molding, especially rotational molding, fluidized bed coating, aggregation coating, powder coating on fusible liner garments, electrostatic powder coating and other methods. different coating powder. Polyethylene that can be used in these processing processes includes high density polyethylene, polyethylene

  medium density, and low density polyethylene.

  These three types of polyethylene are widely used in an efficient manner for different purposes depending on their characteristic. Of these three types of polyethylene, polyethylene

  medium density and low density are generally

  produced in the form of granules, since their manufacturing process has so far been limited

  a solution polymerization process and a poly-

  high pressure merification. As a result, in order to employ these types of polyethylene in powder molding, the granules must be ground by means of mechanical grinding, low temperature grinding, chemical grinding and the like. However, the characteristics of

  particles of the powder thus obtained are unsatisfactory

  due to the fact that the powder has a low bulk density, a high natural angle of friction or slope, a particle size distribution

  wide and a particle shape that is not uniform.

  Therefore, it is difficult to obtain by rotational molding articles in which the complicated parts are

finished with care.

  On the other hand, the high density polyethylene is generally prepared by a slurry or slurry polymerization process and, therefore, is available

  in the form of a powder. However, although the poly-

  High density ethylene has good technical characteristics, such as stiffness, high temperature resistance, sealing properties and analogies, it has the disadvantage that residual stresses or stresses are important because of its high crystallizability, stress large-sized molded articles obtained therefrom is more important than that of articles obtained from medium-density polyethylene and impact resistance, and the ESCR (resistance to cracking or breaking under external stress or from the environment) are weak. In addition, the characteristics of high density polyethylene powder obtained according to a conventional manufacturing process are unsatisfactory in practice for the reason

  that the notch distribution of the particles is generally

  wide, and particularly, a large quantity

  small particles is contained in the powder.

  Therefore, an object of the present invention is to eliminate the above-mentioned disadvantages of the prior art and to provide a resin powder suitable for use in rotational molding and other

powder treatment processes.

  Another object of the present invention is to provide an ethylene-alpha-olefin copolymer powder having an average weight, an extrusion rate or an average creep index, and a low ratio of creep value to high load (21.6 1W a low load creep index (2.16 W), usable in rotational molding, relatively high bulk density, low natural friction or slope angle, particle size distribution narrow and a uniform particle shape in form

  spheres, ellipsoid or the like.

  According to the present invention, there is provided an ethylene-alpha-olefin copolymer powder having the following characteristics: (A) said powder has a density of 0.915 to 0.945 g / cm3, (B) said powder has a creep index from 1 to 80 g / 10 min., (C) said powder has a ratio of the high load creep index under 21.6 kg to the low load creep index under 2.16] which is not greater than 30, (D) said powder has an apparent density of 0.30 to 0.50, (E) said powder has an angle of friction of 250

at 400,

  (F) said powder has a particle size distribution such that the diameter of 50% of the particles of the powder is within the range of 230 to 350 microns and the particle diameter of at least 90% by weight of the total of the powder is within the range of 149 to 500 microns, (G) said powder has particles of the form of a sphere, an ellipsoid or the like and contains substantially no straight-sided particles, with sharp edges, filiform or with lateral protuberances, and

  (H) said powder is obtained from a polymerization

suspension.

  The invention will be better understood and other purposes, features, details and advantages thereof

  will become clearer during the description

  following explanatory diagram with reference to the accompanying schematic drawings given solely by way of example illustrating several embodiments of the invention and in which: - Figure 1 is an electronic photomicrograph (magnification X 100) of the powder particles of the present invention, and using a scanning-type electron microscope; FIG. 2 is an electron photomicrograph (X 50 magnification) of powder particles obtained by mechanical grinding of granules of a commercially available medium density polyethylene, taken using a scanning-type electron microscope, and FIG. 3 is a schematic view of a mold used in powder molding tests, of different types described in detail in the examples and

  the comparative examples given below.

  The alpha-olefins copolymerized with ethylene in the preparation of the powder of the present invention comprise, for example, propylene, butene-1, isobutene, pentene-1, 4-methylpentene-1 and hexene. -1, heptene-1, octene-1 and the like. These alpha-olefins can be used alone or in any mixture

of these.

  The density of the ethylene-alpha-copolymer

  The olefin of the present invention should be within the range of 0.915 to 0.945 g / cc, preferably 0.925 to 0.940 g / cc. In the case where the density is less than 0.945 g / cm 3, the tension, (i.e. warping and collapse) in articles molded from the powder increases disadvantageously and, also, the finish of the detailed or complicated parts of the molded articles (which is hereinafter called "finished complicated parts") becomes bad with respect to the case where the density is within the aforementioned range. In addition, in physical properties, impact resistance and E.S.C.R. decrease as rigidity increases. On the contrary, in the case where the polemic weight is less than 0.915 g / cm 3, the decrease in stiffness, high temperature resistance, lithium resistance and the like become undesirably large and it is relatively difficult to prepare.

  the powder having good characteristics by a polymer

suspension.

  The creep of the ethylene-alpha-olefin copolymer of the present invention should be in the range of 1 to 80 g / 10 min, preferably 2.5 to 30 g / t min. In the case where the creep index is greater than 80 g / 10 min, the tension and finish of the complicated parts becomes poor compared to the case where the creep index is in the above-mentioned range. In addition, physical properties such as impact resistance and E.S.C.R. are

2A64970

  decreased significantly. On the contrary, in the case where the creep index is less than 1 g / 10 min, the powder particles melt with difficulty in a uniform manner with each other since the melt viscosity becomes large. In addition, if the molding temperature is high to solve the mentioned problems

  above, the resin degrades in an undesired manner.

  table, or a large amount of heat stabilizer

is then necessary.

  The ratio of the high load creep index (HMI) at 21.6 kg to the low load creep index (LMI) at 2.16 k 'o of ethylene-alpha-olefin copolymer

  should not be greater than 30, preferably 23 or less.

  In the case where the ratio (HMI / LMI) is greater than 30, the fluidization is not acceptable for the treatment of the powder in which no substantial shear force is present. In particular, when the creep index is low, the lower the ratio, the better is the powder for the treatment process. In addition, when the ratio is decreased, the impact resistance generally increases. However, a copolymer powder having a ratio (HMI / LMI) of not more than 10 is

relatively difficult to produce.

  The apparent density of the ethylene-alpha-olefin copolymer powder of the present invention should be within the range of 0.30 to 0.40, and preferably 0.35 to 0.45. When the apparent density is greater than 50, it is difficult to obtain a polymer powder having the desired powder characteristics mentioned above other than apparent density. On the other hand, in the case where the apparent density is less than 0.30, not only the possibility of using the powder application is not a desirable level, but also the possibility of molding the complicated parts of the articles. becomes inferior to the case in which the apparent density is not

not less than 0.30.

  The angle of friction or natural slope of the copolymer powder of the present invention should be within the range of 250 to 400, preferably 250 to 35. If the angle of friction is greater than 400, the fluidity of the powder decreases undesirably and, therefore, the finish of the complicated parts is not acceptable for use in practice. On the contrary, in the case where the angle of friction is less than 250, it is difficult to obtain the polymer powder having the characteristics mentioned above other than the angle

friction.

  The particle size distribution of the copolymer powder should be such that the diameter of 50% of the particles of the powder is within the range of 230 to 350 microns, preferably 250 to 350 microns, and the particle diameter at least 90% by weight of the total of the powder is within the range of 149 to 500 microns, preferably 210 to 420 microns. The particle size distribution is determined by a JIS (Japanese Industrial Standard) -K-0069 particle size or screening method in which a JIS-Z-8801 sieve is used. In this sieving analysis, a curve called the cumulative distribution curve is obtained. The terms "50% diameter of the particles" of the powder used herein mean the diameter of the powder at the point 50% of the cumulative distribution obtained from the cumulative distribution curve mentioned above. The average diameter of the

  powder is represented by the diameter of 50% of the particles.

  As mentioned above, the copolymer powder of the present invention having a relatively large average particle diameter, and a narrow particle size distribution exhibits good moldability.

  in powder, especially in the finish of the complicated parts

  molded articles. On the contrary, in case

  particle size distribution of the copoly-

  lymere-is outside the area mentioned above,

  the molding capacity of the powder becomes less good.

  For example, the inner surface of the molded articles is not smooth, the thickness of the molded articles is not uniform and the finish of the complicated parts of the articles

  molded is not acceptable for a job in practice.

  The copolymer powder particles of the present invention should be in the form of a sphere, elliptic or the like and do not contain a substantial amount of straight-sided, straight-edged or filament-shaped faces As is illustrated in FIG. 1. On the other hand, powder particles obtained by mechanical grinding of granules according to a conventional method contain substantial amounts of filiform or protruding particles and have very complicated shapes, for example tearing shapes. As illustrated in FIG. 2. In addition, the powder particles obtained by low-temperature grinding of granules at the temperature of the liquid nitrogen contain a relatively small amount of filiform or rope-shaped parts, but straight faces

  and sharp edges in the particles of the powder.

  In the case where the powder particle shapes are very complicated, the fluidity of the powder particles is not good and, therefore, the finish of the complicated parts becomes bad. In addition, as the grinding of granules consumes a large amount of energy and, also, makes the working atmosphere bad because of the creation of noise and the use of refrigerants and solvents in any case, the preparation of particles in powder that requires

  a grinding step is not desirable.

  Ethylene-containing ethylene-alpha-olefin copolymer powder as a main component according to the present invention is preferably prepared by suspension polymerization for

  reasons that all the characteristics mentioned above

  above necessary for the copolymer powder of the

  The present invention can be obtained and the polymer

  Suspended suspension is economically avatagant. The powder obtained by grinding resin granules from solution polymerization and high pressure polymerization is not preferable

in the present invention.

  Since the above-mentioned characteristics of the powder are fulfilled, the other monomers

  such as butadiene and isoprene may be copolymerized

  in the copolymer powder of the present invention.

  The ethylene-alpha-olefin copolymer powder containing, as a major constituent, ethylene according to the present invention can be produced, for example

following way.

  The ethylene is polymerized and contains alpha-olefin and a catalyst at a temperature ranging from room temperature to 100 ° C under a pressure such that the mixture

  polymerization is maintained in a suspended state.

  The catalysts used in the suspension polymerization

  The copolymers of ethylene alpha-olefin include those comprising a hydrocarbon-soluble organomagnesium compound and a transition metal compound or comprising a transition metal compound and an aluminosiloxane. Catalysts comprising a hydrocarbon-soluble organomagnesium compound and a transition metal compound suitable for use in the preparation

  of the copolymer powder of the present invention

  for example, those described in U.S. Patent Nos. 3,989,878; 4,004,071; 4,027,089 and 4,159,965. These catalysts comprise a component

  solid catalyst (A) and an organometallic compound (B).

  The solid catalyst component (A) is a reaction product of compounds (i) and (ii) or compounds (i),

(ii) and (iii) following.

  (i) (a) a hydrocarbon-soluble compound represented in the general formula: wherein d, p, q, r and s are each independently O or a number greater than 0, is 1 or a number greater than 1, p + q + r + s = mo (+ 2, m is the valence of M, M is a metal of groups 1 to 3 of the periodic table, R1 and R2 are each independently a hydrocarbon group having 1 to 20 carbon atoms, X and Y are each independently OR3 OSiR4R 5R6 NR7R8 or SR9 wherein R3, R4, R5, R6, R7 and R8 are each independently a hydrogen atom or a hydrocarbon group having from 1 to 10 carbon atoms and R 9 is a hydrocarbon group having 1 to 20 carbon atoms; (b) a reaction product of the compound (i) (a) with

a siloxane compound.

  (ii) a titanium or vanadium compound containing at least

minus one halogen atom.

  (iii) the halides of A1, B, Si, Ge, Sn, Zn or Sb.

  The organometallic compounds (B) comprise the compounds of a metal of groups 1 to 3 of the periodic table. Preferred organometallic compounds (B) are complexes containing an organoaluminum compound

and an organomagnesium compound.

  On the other hand, aluminosiloxane catalysts and transition metal compounds suitable for use in the preparation of the copolymer powder of the present invention are those described, for example, in U.S. Patent No. 3,787. 323, British Patent Nos. 1,502,964 and 1,502,963. These catalysts are those obtained from the reaction of (i) with a compound of formula R10 2 HSiOAlZ2

2 2

  wherein R 10 is a hydrocarbon group having 1 to 10 carbon atoms, and Z is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms, any mixture thereof with (ii) a titanium or vanadium compound or a complex containing at least one atom

  halogen per atom of titanium or vanadium.

  The copolymerization carried out in the preparation of the copolymer powder of the present invention can be carried out in the same manner as in an olefin polymerization process in which a catalyst

  classic Ziegler type is used. The solvents used

  copolymerization include, for example, aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane,

  decane, kerosene and the like, alicyclic solvents

  such as cyclohexane, methylcyclohexane and the like, aromatic hydrocarbons such as benzene,

  toluene, xylene and the like.

  Although the added amount of comonomer (i.e., alphaolefins) can be changed significantly depending on, for example, the type of alpha-olefins, the polymerization temperature and the partial pressure of ethylene in the reactor, approximately 0.05 to mol, preferably 0.10 to 5 mol of alpha-olefin per mol of ethylene, are generally introduced into the reactor. Thus, copolymers having an ethylene content of 70 mol% or more are generally obtained. The reaction temperature is preferably within a range of from room temperature to 1000C, preferably 50 to 901C. The polymerization reaction is preferably carried out under pressure, generally from ambient pressure to 50 kg / cm 2, or 4.9 × 10 6 Pascals.

  or 49 bar, preferably 2 to 20 kg / cm 2, or 1.96.

  at 19.6 105 pascals. The molecular weight of the copolymer can be effectively controlled by the presence of hydrogen

in the reaction system.

  The ethylene alpha-olefin copolymer powder obtained from the copolymerization process mentioned above may optionally be subjected to a post-treatment step comprising a mechanical attrition treatment and / or a sieving operation. Mechanical attrition treatment can be implemented using a high speed fluidization mixer, such as a

  mixer "Henschel", and different grinding machines.

  The ethylene-alpha-olefin copolymer powder of the present invention is advantageous for use in a powder molding process. As is well known, the powder molding process is one of the plastic molding processes in which the resin powder particles come into contact with a heated mold to melt together this melt followed by cooling, wherein molded articles are obtained. Various powder molding processes are known which are classified according to the movement of the mold and the heating method. For example, the powder molding processes include the Engel process, the Hayashi process, the Hysler process, the tilting rotating mold process, the biaxial rotation molding process and the like, and also include the coating processes of powder, such as the coating of a steel pipe, in which the powder particles are layered on

  a heated substrate while rotating the substrate.

  Although the ethylene-alpha-olefin copolymer powder of the present invention can be used in any conventional powder molding process, including the processes mentioned above, it is especially suitable for use in a molding process. in rotation, including the rotating and tilting mold process, the Hysler process, and the biaxial rotational molding process, in which a mold or substrate is rotated during molding, and the powder coating process

  wherein a substrate is rotated during coating.

  In the case where the powder molding is carried out using the copolymer powder of the present invention, the powder particles flow in a uniform manner and the melting of the particles occurs uniformly. As a result, the inner and outer surfaces of the molded articles are uniform and smooth and finely finished, the non-uniform sections of the molded articles are reduced so that the thickness of the parts

  becomes uniform and the tension (ie the left-handedness)

  and the collapse) of the molded articles is eliminated so as to produce molded articles having a good dimensional accuracy. More particularly, when the copolymer powder of the present invention is used, the finish of the complicated parts of the rotational molded articles is greatly improved over conventional resin powders. For example, in complicated parts, such as the acute-angled corners of the usual molded articles, small or large recessed orifices, pinholes, or bypasses occur. On the contrary, in the case where the capolymer powder of the present invention is used, the surface profile of the mold is faithfully reproduced in the surface of the molded article and, therefore, a neat finish is achieved. As a result, according to the present invention, molded articles having acute angled corners or thin filamentary parts which have been difficult to mold by powder molding, can be formed in a powder molding process.

  using the copolymer powder of the invention.

  In addition, molded articles having a projected surface

  The wide or narrow cross-section is not satisfactorily manufactured by the conventional rotational molding process because the powder particles can not cover all parts of the inner surface of the mold. On the contrary, such articles can be molded using the copolymer powder of the present invention. In addition, according to the present invention, fine and etched patterns can be made on the surface of the molded articles and a relief etching method can be implemented on the molded articles for decorative purposes. As mentioned above, because. the use of the copolymer powder of the present invention, the free form of molded articles is greatly increased and

  additional value is imparted in a remark-

molded articles.

  The molded articles derived from the ethylene-alphaolefin copolymer powder of the present invention have excellent physical properties, especially in the balance of impact resistance and other physical properties and also in the ESCR. can mold good foam products by adding chemical foaming agents to the copolymer powder of the present invention. It should be noted that not only monolayer molded articles but also multilayer molded articles can be satisfactorily molded using the copolymer powder of the present invention.

  invention, and also, it is possible to manufacture in a satisfactory manner

  forming sandwich-type molded articles in which a foam layer is interposed between non-foam layers. The ethylene-alpha-olefin copolymer powder of the present invention may contain, in use, various conventional additives, such as stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, pigments, inorganic or organic fillers of fibrous reinforcing materials, fire retardants, release agents and the like in a conventional manner. In addition, petroleum resins, waxes, liquid rubbers, powdered rubbers and other powdered polymers can be added to the copolymer powder of the present invention in an amount such that the characteristics of the

  copolymer of the present invention are not altered.

  The invention will now be illustrated by the examples below which should in no way be

considered as limiting.

  The physical properties defining the polymer powder of the present invention were determined according to

the following methods.

  Density: ASTM D 1505 Creep rate or extrusion rate: ASTM D 1238 Bulk density: ASTM D 1895 Angle of friction or natural slope: this is the angle that forms, with the horizontal, the edge of a pile of copolymer powder resting freely on a

horizontal support.

  This angle is measured in the following way: a measuring funnel closed with a glass rod is filled with powder. Raise the rod slightly to make

  fall evenly in 60 seconds on a horizontal support

  all the powderiness contained in the funnel.

  We then measure the angle that is made with the horizontal

  edge of the pile of powder thus formed on the support.

  Particle Size Distribution: JIS K 0069 Synthesis of the Solid Catalyst The solid catalysts used in the Examples and Comparative Examples below were synthesized in a 10 liter stainless steel autoclave in the manner described.

next.

  (1) Solid catalyst A 0.30 mol of a titanium compound having the formula Ti (O n -C 4 H) C 13 and 0.30 mol of an aluminosiloxane having the formula Al (OSiH, CH 3 C 2 H 5) (C 2 H 5) Cl were charged with 6 l of hexane in the autoclave. The mixture was reacted at a temperature of 70 ° C. for 5 hours. The mixture

  The reaction mixture was filtered to isolate the catalyst

  solid. The solid catalyst thus obtained was washed with hexane until no free halogen was detected in washing hexane. This catalyst is

  mentioned as a solid catalyst A below.

  (2) Solid catalyst B 0.20 mol of a reaction product of (C2H5) (nC4H9) Mg and hydromethyl polysiloxane having a viscosity of 30 centistokes in a ratio of Si / Mg = 1.5 / 1.0 and 0.24 moles of titanium tetrachloride were charged together with 6 liters of hexane in the autoclave. The mixture 24l64970 was reacted at a temperature of 10OC for 3 hours. The reaction mixture was subjected to the aftertreatment described in the synthesis of solid catalysts A, whereupon a solid catalyst was obtained. This catalyst is mentioned as the solid catalyst B below. (3) C solid catalyst 0.20 mol of a reaction product of (iso-C4H9) (n-C4H9) Mg and a methylhydroxy siloxane tetramer in a ratio of Si / Mg = 1.0 / 1.0, and 0.20 moles of titanium tetrachloride were charged together with 6 liters of hexane in the autoclave. The mixture was reacted at -200C for 4 hours. The reaction mixture was treated in the same manner as in the case of solid catalyst A, so as to obtain the solid catalyst. This catalyst is mentioned as the solid catalyst C below. (4) Solid catalyst Dg of Mg (OC 2 H 5) 2. 3 liters of TiCl 5 (0 n-C 4 H 9) 5 and 3 l of hexane were loaded into the autoclave, and reacted at a temperature of 1401C for 2 hours. The reaction product was treated in the same manner as in the case of solid catalyst A. Thus a solid catalyst was obtained. This catalyst is mentioned

  as a solid catalyst D below.

  (5) Solid Catalyst E The reaction and subsequent treatment in the case of the solid catalyst D were repeated except that titanium tetachloride was used as the titanium compound. There was thus obtained a solid catalyst. This catalyst is mentioned as the solid catalyst E below.

  Preparation of the ethylene-copolymer powder

alpha-olefin.

  Different types of ethylene-copolymer powder

  alpha-olefin were prepared as described in the Examples and Comparative Examples below. The characteristics of the powder particles thus prepared

  are listed in Table 1 below.

Example 1

  A copolymer was prepared by a polymerization process.

  In a 200-liter stainless steel reactor, the temperature of the reactor was maintained at a temperature of 80 ° C. The polymerization reaction was carried out by adding to the reactor, as a catalyst mixture, 1.1 g. Hr of a solid catalyst A, m mol / Hr of aluminosiloxane having the formula Al (OSiH.CH3.C2H5) (C2H5) Cl and 7.5 m mol / Hr of n-butyl orthotitanate and also, adding to the reactor 30 l / Hr hexane, 2.1 l / Hr butene-1 as alpha-olefin and ethylene containing 0.3% hydrogen in an amount

  sufficient to obtain 10 to 12 kg / Hr of copolymer.

Example 2

  The polymerization reaction of Example 1 was repeated except that 0.15 g / Hr of the solid catalyst B and 6 m mol / Hr of triethylaluminum were used as the catalyst and 7.8 l / I was used. Hr of hexene-1, as

  alpha-olefin and ethylene containing 0.6% hydrogen.

Example 3

  The polymerization reaction of Example 2 was repeated except that the reaction temperature was 75 C, and was used as a catalytic mixture.

  0.21 g / Hr of solid catalyst B and 15 m mol / Hr of triethyl-

  aluminum, and that 3.0 l / Hr of butene-1 was used as the

  alpha-olefin and del.ethylene containing 0.7% hydrogen.

  The resulting copolymer powder was subjected to a high speed fluid mixing treatment using a Henschel mixer at a temperature of 70 ° C.

for 1 minute.

Example 4

  The polymerization was carried out under the same conditions as in Example 1, except that the polymerization temperature was 85 ° C., and that 3.7 l / hr of 4-methyl-pentene-1, as alpha-olefin and ethylene

  containing 0.3% hydrogen were used.

Example 5

  The polymerization was carried out in the same

  as in Example 3, except that the polymerization temperature was 85 ° C. and that 0.20 g / Hr

  solid catalyst C and 6 m mol / Hr of diethyl hydride

  aluminum, as catalytic mixture and 2.8 l / Hr of butene-1, as alphaolefin and ethylene containing

  0.6% hydrogen was used.

Example 6

  The polymerization was carried out under the same conditions as in Example 1, except that the polymerization temperature was 75 ° C. and 1 h of pentane, as polymerization medium, 2.5 l / Hr was used. butene-1, as alpha-olefin, and ethylene containing

0.3% hydrogen.

Example 7

  The polymerization was carried out in the way that

  in Example 1, except that the polymerization temperature

  This was 70 C and 30 I / Hr of butene was used as the polymerization medium, 3.0 I / Hr of butene-1 as

  alpha-olefin and ethylene containing 0.4% hydrogen.

  The resulting powder was subjected to a high speed fluid mixing treatment in a Henschel mixer

  at a temperature of 70 C for 1 minute.

Comparative Example 1

  The polymerization was carried out in the same manner as in Example 1 except that 1.5 g / Hr was used

  of a solid catalyst D and 30 m mol / Hr of triethylaluminum

  as catalytic mixture, 2.5 l / Hr of butene-1 as alpha-olefin and ethylene containing 0.8% of hydrogen.

Comparative Example 2

  The polymerization was carried out under the same conditions as in Comparative Example 1, except that the reaction temperature was 75 ° C., and 2.9 l / hr of butene-1 and ethylene were used. containing

1.0% hydrogen.

Comparative Example 3

  A copolymer was prepared by a polymerization process.

  In a continuous reactor in a stainless steel reactor of 1. While the reaction temperature was maintained at 80 ° C., the polymerization was carried out by adding 0.9 g / Hr catalyst E and 40 m mol to the reactor as a catalytic mixture. / Hr of ethyl aluminum ethoxide having the formula Al (C2H5) 2.7 (0C2H5) 0.3, and also, adding to the reactor, 70 1 / Hr of hexane, 1.6 1 / Hr of butene -1, as alpha-olefin, and ethylene containing 0.3% hydrogen in an amount sufficient to obtain 6 to 7 kg / Hr of copolymer. The copolymer powder thus obtained was subjected to a high speed fluid mixing treatment.

  at a temperature of 8500C for 7 minutes.

Comparative Example 4

  The polymerization was carried out under the same conditions as in Comparative Examples 2, except that 0.8 l / Hr of hexene-1 was used as alpha-olefin.

  and ethylene containing 1.0% hydrogen.

Comparative Example 5

  The polymerization was carried out under the same conditions

  than in Comparative Example 1, except that 1.2 g / Hr of solid catalyst E and 15 m mol / Hr of triethylaluminum were used as the catalytic mixture, and 2.3 l / Hr of butene- 1, as alpha-olefin, and ethylene containing

1.1% hydrogen.

Comparative Example 6

  High density polyethylene powder available

  in commerce from suspension polymerisation.

  (Suntec R 340 P manufactured by Asahi Kasei Kogyo Kabushiki Kaisha) was used, as a sample of Comparative Example 6, in determining the tests.

described below.

Comparative Example 7.

  A mechanically molded, commercially available, medium density polyethylene powder (Neozex 4330 P manufactured by Mitsui Sekiyu Kagaku Kogyo Kabushiki Kaisha) was used as a comparative example 7 in the implementation.

  performs the tests described below.

Comparative Example 8.

  As a sample of Comparative Example 8 in the evaluation of the tests described below, a commercially available, mechanically molded medium density polyethylene powder (Neozex 4330 P manufactured by Mitsui Sekiyu Kagaku Kogyo Kabushiki Kaisha) was used as the sample. Comparative Example 8 in carrying out the tests described below. Evaluation test of the characteristics of the powder

  copolymer of ethylbene-al; ha-olefin.

  The characteristics of the rotational molding of

  different types of ethylene-copolymer powder

  alpha-olefin examples and comparative examples mentioned above were evaluated as described below. The results are shown in the

Table 1 below.

  The physical properties of the ethylene-alpha-olefin copolymer powder samples of the examples and comparative examples mentioned above were calculated using specimens obtained from a presm X molding. The results are shown in

Table 2 below.

  1) A 500 liter truck tank was molded

  by a rotating and tilting mold process.

  Molding conditions Mold: made from a metal sheet

2 mm thick.

Weight of the articles: 20 kg.

  Heating: propane gas burner, 20 minutes.

  Cooling: cooling by ventilation, mn. Assessment Standard a) Foam Suppression: Assessment of Capacity

  the melting of the powder particles.

  +: no foam present in the molded article.

   : presence of foam on a small dimension

in the molded article.

  -: presence of foam on a small and a -

  much of the entire surface of the molded article.

  b) Deformation or molding tension: evaluation

  dimensional accuracy of the molded article.

  +: global deformation and local warping and

  collapse are not observed in the molded article.

  +: we observe a gouging and a collapse

  local bin that general debromination is not observed.

  xne.zoddej.ed seapuTlHo qged snId salt suBp eipnod ap seInoT.Jed sep% uemalnooil a ToBedeo eBI enteAg inod mm L6 ep inanruol w ith unoeqo. e luemaATodsad 5ú mum 0'6ú 1 @ e mm 0'1ú 'mm 9'61' & m Z'01 op sJqmBTp sep% utee to 1 'Zl'11 uoTeoaeojd ue xneao saepuTIo op Tunm 9:% qe O a1Inom ao (I3 (o $ Teoa eainom a jed eajp --jsa9 o) eaeTxeTq uOTIu4oJ jed ea2enom ep gpgooJd an eBd gtnoom 99e sepnhTldmoo saeTied sep TuTj ael jesae nod O0 ean2j el suep TaJDpsa, inbet. ainom a (Z AasTogd uou eaTuem eunp

* gtnom '91name TalpJe, l P 2ndTjp ee np% amsos: -

  In Tnom elopTJe1t ep eeleeTj np.emmos ne s9uasgd suoTsuamTp saTa.d ap snoa% ap sq.Tuenb sa.Tad: +; Z TaloTael TaloTael suep 'alnom uosTeedmoo aed'% uemaeTjpT seTnpoidai se9alTTj seTIjed: + (d 5'9 5 95 peaq ali.uT siu: eeealTj ap UoTSUamTa) 'lnom ealoTaJe, lp sagnbTIdmoo seaTaed sap TU $ np uoTenIeA9: eaeeITj ap aSeInoN (e OZ * mm 8'0; Z'1 euTemop np s.oqep ue

  Thnom alOTJBel ap te.azer ueld unmp inessTede: -

  * mm 9'40 + Z'7 eaue 9n.Ts 9anom aloTjel apeingB ueId unp inassTedg: + * mm $ o + Z4 'suep esTadmoo 51 9Info ealoTje, 1 op leia1le uuId un4p inessTedp: + To Inom aloTael ap ednoo ua inassTedg9p 9% Tm -jojTunl ap uoTenleAg: inessTedg9p 9.TujojTunf (p aujaeuT eoejans ap anA.aeu ae 9glnom IOT%: eI ap euaeq.uT eoejns eBI ep ajqTlue aoejans el ans O

  a.tuspad aiTeInuea eannqon.zs ap qqTuenb apuei: -

  Lnom ealoTajel eoujans eejans el ans quemaleoot ea.uesgad aTelnueai eanona.s ap 9% Tuenb eTed: + uemLo; Tun% eAssit% uemeaJTu aujaequ eoejans: + Aelnom eIOTeBl 5 and then under 9% 9 No 9q. Tm.Zo; Tunl ap uoTen-IeA: sua @ aUT aoeBans el ap 9.TTe2g (o To% uamaapuo3je a% a teOOI% uemassTqOneS un.e

  esieapus uOTeuaojgp to STOJ etl q ea.esqo uo: -

  OZ6i97Z two larger cylinders. The mold 10 has also been provided with a number of projecting corners 15 to evaluate the reproducibility of the plug. The length a and the width

  b of the mold 10 are 268.5 mm and 367 mm respectively.

  Molding conditions Mold: cast aluminum with a thickness of 2mm Weight of articles: 600 g Heating: hot air with a temperature of 3000C, 15 mn Cooling: cooling by ventilation

mn, cooling with water 2 mn.

  Evaluation Standard +: the sharp corners 15 nt clearly molded

  and the projected portions 11 and 12 uniformly molded.

  +: nicks and scratches are present to some extent in the projecting corners 15, and small holes or needle holes are present at the top of the projection moldings 11 and 12, although the parts

  in projection 11 and 12 are molded.

  -: nicks and scratches present in the molded projections 15, and the projection portion 11 is not completely molded and small holes are present at the top of the projection portion 11 and 12, although

Part 12 is molded.

  - - 1 - T I e i -,? O! ! + + + + + + + + + T + + +: + + + + + + + + + + + + + + + + + T + 4: + + + + + + + + + + + + + + + + + + + + + + + 8Z,

L.'91.

  6 '1 6'1, Z'i Ole Sb ú "9.9 0'LL gz t 01t 7' 0'2 Z'oe 9a LZ ú'171

Io.

  9'z2 z2z zz {z'6 8'L ûi ZI '1 9Z' O 'LZ Z'l ú 6'ú Z'oe 176L-o' 1.G 0eL ú'6Z 6'9i 9alz 9'qú 9 '17 O '9'C: 1. 1. 6'1: 1. OIZ 01.2 OZZ OúZ O9Z O0ú 09Z 0? Ú ú 09Z úil ú úú 9ú'0 6ú'0 ú'0 ú'0 ú'0 0ú'0 0'0 6Z'0 8ú'0 '1ú'0 ú' 0 9Z'O çú '0 0ú' O 9ú '0

Z1.2 '

'ú ú ú ú ú ú ú ú ú seoi

! ú96'0

Z86'0

ú176 'O0

ú 6'0 6ú6'0 Z6'0 0ú6'0

1716 'O0

6'0 6ú6'0 6ú6'0 6ú6'0 6ú6'0

626 '0

  6ú6'0 L imi L u 9, S, 17 eD2IDxm 1q7 "my he has ú a Uidmaw Z a", "Tnznn _ _. - q '] 7 = -1 - -1t (d ez% I v- - uv qntd: iLdo.zsnesBs I I-zoo Dwnil al't name itSsep% uem p op -ap ep eap'u eT% .9.o% 05 e 4Oj al.ueei9l anblm opall 'F a u.emB ap uo sarnoT .sepd sep tp a4p -eddR I'I ap -nIOA - ll - lM 4o $ f.ax nua uoTnqrgTa.si al gsu N a SP d ONt

_. __ '(__U9% Tu (PO to o ..

  O "O 4. oi cM l gdçzlçlllz! Yc 0'Z The 8 v'a

a 4 1-

  y ', x 1 OrP, 11, 1 1, "tcc 1 2', O 1 -114 +: o 0 & k neeEqej,

Table 2

(1) ASTM D 638

(2) ASTM D 638

(3) ASTM D 256

(4) ASTM D1822

(5) ASTM D1693

  (Specimen of 3 μm thick, 500C, 10% Noigen *) * Polyethylene Nonylphenyl ether No. Limit & 1) Elongation- (2) Resistance (3) Resistance (4) ESCR (5) of elongation Tensile tensile stress and (h) (kg / cm2) at Izod at impact rpture (with (kg.cm/cm2) ru% -r notch) x.1 170 300 180 420 steps break x.4 173 300 42 160 340 x.5 185 300 15 100 36 x.6 130 300 steps of 210 500 rupture x.7 105 300 steps of 240 500 rupture Ex raf 5 168 300 23 160 350

6,230 300 5 76 4

  Of course, the invention is not limited to the embodiments described and shown which have been given by way of example. In particular, it includes all the means constituting technical equivalents of the means described and their combinations if they are executed according to its spirit and put

  implemented in the context of protection as claimed.

  0t6'0 1% Z6'0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0% 0% 1%% * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * , p e.jqmlodoo el e auuxeaq -auqlq, p eazau.odoo el leuanq-l-auqlXqlp eaqmltodoo 0u el aed 9nlTlSUOo ednoaS el suep TsToqo jse eaq "ulodoo I.Tpal nb ao ue eoS9ToJ ese 'I uoTeoTpueAe BI uolas euT9oeqdte-euatql94p euImXlodoo ep aepnod z uo T T oles oles oles H H H H H H H H H H H H H H H H H H H H H H H H H zo zo zo zo zo zo zo zo zo zo zo au au au au au au au au au au au au au au au aeTtItS amuo aunp no apiosdTtla unp aeqds aunp aeuo; el snos% ue.9 aepnod aTpel (o) d 00 OZ q 6 a1 ap auTemop np JnaTjq: uTtI B% its aeluol. epnod and Op spTod ua% 06 suTom nesp solno0Taed sap eJtmeTp el o at OSU OZ p uToop ro p np naTsiu, lt% sea aepnod el ap gslnoTIeud sap% o0 ap a9umsTp ael anb allat. salnoTed sap alITei u ua uoTnqTasTp aun e eapnod eaTpel (&) 51 z op luemaSlW; J op algue an aipnod a ^ pBI (3) o0u'0 p aeua edde% .Tsuap aun e eapnod aTpeI (a) 0u e anae.zdns ssd q.Sau Tnb SX 91Z 'snos e2uqo aelqTej O eS aSen $ j ep asoTputl S 9'4Z snos 92jeqo eaneq e 9s2enj ep aoTpuç, t ep zoddeB a eipnod elTpel (D) um 01/2 08 e I ap 92in1j ap aoTpuT an aepnod alTpel (g) $ úm OE Bd 9-WO '0 es 16'0 ap anbTuntoA spTod a e aapnod a% pel (Y): anb ao ua aes a.% oezeo 'aueItq;, qI ap' ted -uî.d% ueni-suoo eamuoo '% ueuauoo aipnod ua aIelnom ael inod eu6J SNo-eqdtIeu @ 9p e.xeitodoo Sp aIpnoc * l SN 0 I 1 y DI 4. The ethylene-alpha-olefin copolymer powder according to claim 1, characterized in that the index

  creep of the powder is between 2.5 and 30g / 10mn.

  Ethylene-alpha-olefin copolymer powder according to Claim 1, characterized in that the ratio of the low load creep index under 2.16 kg to the high load creep index under 21.6 kg is not

not greater than 23.

  6. The ethylene-alpha-olefin copolymer powder according to claim 1, characterized in that the density

  Apparent powder is between 0.34 and 0.45.

  An ethylene-alpha-olefin copolymer powder according to claim 1, characterized in that the angle

  friction is between 25 and 35 '.

  e. An ethylene-alpha-olefin copolymer powder according to claim 1, characterized in that said powder has a particle size distribution such that the diameter of 50% of the particles is between 250 and 350 p, and the diameter of the particles of at least 70% by weight of the total of the powder is between 210 and 420i. 9. The ethylene-alpha-olefin copolymer powder according to claim 1, characterized in that said copolymer is obtained by polymerization of ethylene in the presence of an alpha-olefin other than ethylene and

  a catalyst with a temperature between

  ambient temperature and 100 C under a pressure such that the polymerization mixture is maintained in a slurry state, said catalyst comprising a solid component (A) and an organometallic component (B), the solid component (A) being produced by reacting a hydrocarbon-soluble organomagnesium compound (IIa) of formula M2Mg RXY8 wherein: di, p, q, r and s are each independently 0 or a number greater than 0, P is I or a number greater than 1, p + q + r + s = mi + 2 È, am is the valence of M, N is a group 1 to 3 metal of a periodic classification, R1 and R2 are each independently a hydrocarbon group having 1 to 20 carbon atoms , X and Y are each independently OR3, OSiR4RSR6, NR7R8 or SR9, wherein R3, R4, R5, R6, R7 and R8 are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms and R9 is a hydrocarbon group having from 1 to 20 carbon atoms; or (i-b) a reaction product of a hydrocarbon-soluble organomagnesium compound (i-a) with a siloxane compound; (Ii) a titanium or vanadium compound having at least one halogen atom; and (iii) a halogenide of Al, B, Si, Ge, Sn, Zn or Sb, or said catalyst being produced by reacting (iv) at least one compound of the formula R 1 O 2 SiO 2 Z in which R 10 is a hydrocarbon group having 1 to 10 carbon atoms, Z is a hydrocarbon group having 1 to 20 carbon atoms, with (v) a titanium compound or

  vanadium or a complex having at least one halogen atom.