Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/24—Acids; Salts thereof
  • C08K3/26—Carbonates; Bicarbonates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/52—Phosphorus bound to oxygen only
  • C08K5/524—Esters of phosphorous acids, e.g. of H3PO3

Definitions

• the present invention relates to the use, for extrusion, of compositions based on polymers of alpha-olefins. It relates more particularly to the use, for the manufacture of objects by extrusion followed by water cooling, of compositions based on propylene polymers.
• the polymers of alpha-olefins in particular the polymers of lower alpha-monoolefins such as ethylene and propylene are thermoplastic polymers suitable for processing by extrusion.
• An important outlet for this transformation process lies in the production of films, sheets, tubes and filaments.
• propylene polymers a large volume of these extruded polymers is intended for the manufacture of fibers and films. These can for example be used as such as packaging films, can be cut into strips for weaving, or can be fibrillated for various textile applications.
• the films and filaments generally undergo stretching in order to increase their resistance. Furthermore, the films can be cut into strips before stretching.
• compositions based on alpha-olefin polymers make it possible to manufacture objects by extrusion followed by cooling with water, without the latter being entrained, even for high extrusion speeds, and without harming the other essential properties of the extruded objects.
• Patent FR-A-1345203 (from SHELL INT. RES. MIJ). mentions that the addition to polyolefins of the combination of organic sulfur and phosphorus compounds and an organic or inorganic base would give these polyolefins good heat and light stabilization (page 1, col. d, last paragraph).
• the basic proportion is between 0.1 and 5% approximately, for example between 0.3 and 1% approximately (page 3, col. D, lines 4 to 7).
• the alpha-olefin polymers used in the compositions which can be used according to the invention are polymers containing at least 50 mol% and preferably at least 75 mol% of terminal unsaturated olefins the molecule of which contains from 2 to 18 and preferably from 2 to 6 carbon atoms such as ethylene, propylene, butene-1, pentene-1, methylbutenes-1, hexene-1, 3- and 4-methylpentenes-1 and vinylcyclohexane. They are more particularly polymers containing tertiary carbon atoms such as highly isotactic crystalline polymers of butene-1, 4-methylpentene-1, and very particularly, propylene.
• They may also be copolymers of these alpha-olefins with each other and / or with diolefins comprising from 4 to 18 carbon atoms, such as non-conjugated aliphatic diolefins such as, for example, 1,4-hexadiene or such that alicyclic diolefins having an endocyclic bridge such as dicyclopentadiene for example.
• these may be block copolymers which consist of successions of chain segments of variable lengths, each segment consisting of a homopolymer of an alpha-olefin or of a random copolymer comprising an alpha-olefin and at least one comonomer chosen from alphaolefins and diolefins.
• compositions which can be used according to the invention can also be based on mixtures of two or more polymers as described above.
• the polymers which can be used can be prepared according to known methods of polymerization of alpha-olefins at low pressure.
• highly isotactic crystalline homopolymers of propylene can be prepared in the presence of stereospecific catalytic systems based on organometallic compounds and titanium chlorides being at a valence lower than its maximum valence.
• compositions which can be used according to the invention comprise at least one constituent (a) which is any phenolic antioxidant.
• This antioxidant can be advantageously chosen from the group of alkylated mono-, poly- and thiobis-phenols.
• alkylated monophenols mention may be made of 2,6-di-tert-butyl-p-cresol and (3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octa-decyl .
• alkylated polyphenols mention may be made of methylene tetrakis (3,5-di-tert-butyl-4-hydroxy) methane dihydrocinnamate, 2,2'-methylene bis (4-methyl-6- terephthalate) tert-butylphenol), 2,6-bis- (2'-hydroxy-3-tert-butyl-5'-methylbenzyl) -4-methylphenol and tris- (3,5-di-tert-butyl isocyanurate) -4-hydroxy) benzyl.
• compositions which can be used according to the invention can also comprise a mixture of the phenolic antioxidants listed above.
• compositions which can be used according to the invention comprise at least one component (b) which is an organic phosphite.
• component (b) which is an organic phosphite.
• the main result of incorporating component (b) is to increase the effectiveness of the above-mentioned phenolic antioxidants.
• This organic phosphite is advantageously chosen from the phosphites and thiophosphites of general formula (RO) 3 P and (RS) 3 P in which the radicals R, which are identical or different, represent an alkyl, aryl, alkylaryl, cycloalkyl or alkoxyalkyl radical and among the cyclic phosphites derived from pentaerythritol.
• Preferred phosphites as constituents (b) are, on the one hand, the trialkylphosphites such as the triethyl-, tributyl- and trinonylphosphites for example and, on the other hand, the dialkylpentaerythritol diphosphites, such as the distearylpentaerythritol diphosphite for example. Mixtures of these phosphites can also be advantageously used.
• compositions used according to the invention finally comprise at least one component (c) which is a carbonate of an alkaline earth metal.
• All the alkaline earth metal carbonates are suitable as constituents (c). Mention may be made, for example, of magnesium, calcium, strontium and barium carbonates. However, it is preferred to use calcium carbonate, and in particular calcium carbonates which are in the form of particles with an average diameter of less than 10 microns.
• the so-called "aforementioned” calcium carbonates that is to say the calcium carbonates obtained by carbonation of a lime milk, are very suitable.
• Components (a) and (b) are incorporated into the compositions used in accordance with the invention in the usual stabilizing amounts. These amounts are generally between 0.005 and 10% by weight of the polymer entering into the composition and preferably between 0.01 and 5%. More particularly, these quantities are of the order of 0.05 to 0.5%.
• Component (c) is incorporated into the compositions in an amount of 0.1 to 50% (per thousand) by weight of the polymer approximately, preferably in an amount of 0.1 to 10%.
• the mean diameter of its particles is a fraction of a micron. More particularly, the particles have an average diameter of between 0.05 and 0.8 microns. It has been found in fact that if the size of the particles of component (c) is greater, this results, in the case of the extrusion of films cut into strips, of rapid wear of the cutting blades.
• compositions which can be used according to the invention can contain other usual additives such as, for example, other antioxidants such as thioesters generally derived thiodipropionic acid, other polymers, agents that facilitate processing, reinforcing agents, pigments, fillers, lubricants, anti-static agents, etc.
• Components (a), (b) and (c) can be incorporated into the polymer in any manner known per se, for example by dry mixing or by impregnating the polymer in powder or granules by means of a solution of the components in a suitable solvent, alone or as a standard charge with other ingredients, or by mixing a solution or a suspension of the polymer with a solution of the constituents.
• the incorporation can be carried out for example, either in a mixer or a grinder where the solvent is evaporated, or by kneading on heated cylinders or by extrusion of a mixture of the polymer and the other constituents.
• compositions which can be used according to the invention can be carried out according to all the conventional techniques known to those skilled in the art.
• the characteristics of the apparatus will obviously be chosen as a function of the transformation which it is desired to subject to the composition to be extruded and of the type of object which it is intended to shape.
• the cooling or quenching treatment by means of water it is carried out at a temperature which depends on the nature of the extruded object and on the properties which it is intended to confer on the latter.
• the temperature of the quench bath of the primary film is generally between approximately 20 and approximately 50 ° vs.
• the use for the extrusion of the compositions according to the invention therefore provides an elegant solution to the problem of the entrainment of water, by these compositions, when they are cooled with water.
• the use, which is the subject of the invention, of the compositions described above makes it possible, surprisingly, to ensure an excellent compromise between the elimination of the entrainment of water even at extrusion speed. high, the initial coloring and the anti-corrosion efficiency, a compromise which is not achieved with the compositions of the prior art.
• compositions which can be used according to the invention contain “aforementioned” calcium carbonate in particles of average diameter of the order of a fraction of a micron, do not soil the extruder die; during the extrusion of films which are cut into strips, they do not cause premature wear of cutting knives.
• This granulated composition is then extruded in the form of a film approximately 100 microns thick.
• This film is cooled by passing through a water bath at room temperature (25 ° C) and then cut into strips which are stretched, at a stretching rate of about 1/6 in a stretching oven brought to a temperature 150,180 ° C. .
• This composition is transformed into strips as indicated in Example 1. These strips show the same properties as those found for the strips of Example 1.
• An extrudable composition is prepared as in Example 3, except that SOCAL U1 is replaced by 0.5 part by weight of calcium stearate.
• SOCAL U1 is replaced by 0.5 part by weight of calcium stearate.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Artificial Filaments (AREA)

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Publications (2)

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Citations (7)

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• 1977
  • 1977-06-07 FR FR777717978A patent/FR2393829A1/fr active Granted
• 1978
  • 1978-05-29 CA CA304,337A patent/CA1112013A/fr not_active Expired
  • 1978-06-01 EP EP78200028A patent/EP0000084B1/fr not_active Expired
  • 1978-06-01 DE DE7878200028T patent/DE2862482D1/de not_active Expired
  • 1978-06-02 BR BR7803570A patent/BR7803570A/pt unknown
  • 1978-06-05 US US05/912,071 patent/US4190624A/en not_active Expired - Lifetime
  • 1978-06-06 JP JP6735778A patent/JPS543149A/ja active Granted
  • 1978-06-06 AT AT0411078A patent/AT385044B/de not_active IP Right Cessation
  • 1978-06-06 ES ES470543A patent/ES470543A1/es not_active Expired
  • 1978-06-07 IT IT24300/78A patent/IT1094840B/it active

Patent Citations (7)

Non-Patent Citations (5)

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