Propylene polymer fibers
阅读说明：本技术 丙烯聚合物纤维 (Propylene polymer fibers ) 是由 R·迪帕洛 J·马蒂波尔奎雷斯 R·勒迈尔 C·卡瓦列里 于 2020-05-18 设计创作，主要内容包括：一种丙烯均聚物用于生产纤维的用途；其中所述丙烯均聚物的特征在于：-熔点范围为150℃至164℃；-在25℃下二甲苯可溶级分在6.0wt％与2.0wt％之间；-在25℃下丙酮可溶级分在0.5wt％与2.0wt％之间；-在25℃下二甲苯可溶级分/在25℃下丙酮可溶级分的比率在30wt％与60wt％之间；-多分散指数范围为2.8至4.5；熔体流动速率(ISO 1133,230℃/2.16kg)为2至40g/10min。(Use of a propylene homopolymer for the production of fibers; wherein the propylene homopolymer is characterized by: -melting point in the range of 150 ℃ to 164 ℃; -a xylene soluble fraction at 25 ℃ between 6.0 and 2.0 wt%; -an acetone soluble fraction at 25 ℃ between 0.5 and 2.0 wt%; -the ratio xylene soluble fraction at 25 ℃/acetone soluble fraction at 25 ℃ is between 30 and 60 wt%; -a polydispersity index ranging from 2.8 to 4.5; the melt flow rate (ISO 1133, 230 ℃/2.16kg) is from 2 to 40g/10 min.)
1. Use of a propylene homopolymer for the production of fibers; wherein the propylene homopolymer is characterized by:
-melting point in the range of 150 ℃ to 164 ℃;
-a xylene soluble fraction at 25 ℃ between 6.0 and 2.0 wt%;
-an acetone soluble fraction at 25 ℃ between 0.5 and 2.0 wt%;
-the ratio acetone soluble fraction at 25 ℃/acetone insoluble fraction at 25 ℃ is between 0.30 and 0.60;
-a polydispersity index ranging from 2.8 to 4.5;
a melt flow rate (ISO 1133, 230 ℃/2.16kg) of from 2 to 40g/10 min.
2. Use of the propylene homopolymer as claimed in claim 1 for producing fibers; wherein the propylene homopolymer has a melting point of 155 ℃ to 163 ℃.
3. Use of a propylene homopolymer as claimed in claim 1 or 2 for the production of fibers; wherein the xylene soluble fraction at 25 ℃ is between 5.0 wt% and 2.5 wt%.
4. Use of a propylene homopolymer according to any one of claims 1 to 3, wherein the xylene soluble fraction at 25 ℃ is between 4.5 and 3.0 wt%.
5. Use of a propylene homopolymer according to any of claims 1 to 4 for the production of fibers wherein in the propylene homopolymer the acetone soluble fraction at 25 ℃ is between 0.8 and 1.5 wt%.
6. Use of a propylene homopolymer according to any of claims 1 to 5 for the production of fibers, wherein in said propylene homopolymer the ratio acetone soluble fraction at 25 ℃/acetone insoluble fraction at 25 ℃ is between 0.35 and 0.55 wt%.
7. Use of a propylene homopolymer according to any of claims 1 to 6 for the production of fibers, wherein in said propylene homopolymer the ratio acetone soluble fraction at 25 ℃/acetone insoluble fraction at 25 ℃ is between 0.43 and 0.50 wt%.
8. Use of a propylene homopolymer as claimed in any one of claims 1 to 7 for the production of fibers, wherein in the propylene homopolymer the polydispersity index is from 3.0 to 4.0.
9. Use of a propylene homopolymer according to any one of claims 1 to 8 for the production of fibers, wherein in said propylene homopolymer the melt flow rate (ISO 1133, 230 ℃/2.16kg) is between 5.0 and 20.0g/10 min.
10. Use of a propylene homopolymer according to any one of claims 1 to 8 for the production of fibers, wherein in said propylene homopolymer the melt flow rate (ISO 1133, 230 ℃/2.16kg) is between 7.0 and 15.0g/10 min.
Technical Field
The present invention relates to the use of polypropylene homopolymer for fibers. Wherein the propylene homopolymer has specific characteristics such that a fiber with low smoke can be obtained and the resulting fiber exhibits increased tenacity.
Background
Polypropylene has long been extruded into fibers. For example, international patent application WO95/032091 discloses fibers comprising a propylene homopolymer or copolymer having a melting point of from 100 ℃ to 145 ℃.
Although polypropylene fibers have been known for decades, there is still a desire to improve their properties. Furthermore, due to recent regulatory restrictions on phthalates, it is desirable to make polypropylene fibers free of phthalate residues from the typical ziegler natta catalysts used to make them.
Disclosure of Invention
The applicant has found that by using a propylene homopolymer having a specific molecular weight distribution of the xylene soluble fraction, it is possible to obtain fibres having good tenacity.
The present invention therefore relates to the use of propylene homopolymers for producing fibers; wherein the propylene homopolymer is characterized by:
-melting point in the range of 150 ℃ to 164 ℃;
-a xylene soluble fraction at 25 ℃ between 6.0 and 2.0 wt%;
-an acetone soluble fraction at 25 ℃ between 0.5 and 2.0 wt%;
-the ratio of acetone soluble fraction at 25 ℃/fraction insoluble in acetone at 25 ℃ is between 0.30 and 0.60;
-a polydispersity index ranging from 2.8 to 4.5;
a melt flow rate (ISO 1133, 230 ℃/2.16kg) of from 2 to 40g/10 min.
Detailed Description
The present invention therefore relates to the use of propylene homopolymers for producing fibers; wherein the propylene homopolymer is characterized by:
-melting point in the range of 150 ℃ to 164 ℃; preferably from 155 ℃ to 163 ℃; more preferably from 158 ℃ to 163 ℃;
-a xylene soluble fraction at 25 ℃ between 6.0 and 2.0 wt%; preferably between 5.0 wt% and 2.5 wt%; more preferably between 4.5 wt% and 3.0 wt%;
-an acetone soluble fraction at 25 ℃ between 0.5 and 2.0 wt%, preferably between 0.8 and 1.5 wt%;
-the ratio of acetone soluble fraction at 25 ℃/fraction insoluble in acetone at 25 ℃ is between 0.30 and 0.60; preferably between 0.35 and 0.55, more preferably between 0.43 and 0.50;
-a polydispersity index of 2.8 to 4.5; preferably in the range of 3.0 to 4.0;
-a melt flow rate (ISO 1133, 230 ℃/2.16kg) between 2 and 40g/10 min; preferably between 5 and 20g/10 min; more preferably between 7 and 15g/10 min.
The polypropylene homopolymer used to produce the fibers according to the invention has a very low oligomer content, which means that smoke generation during fiber production can be significantly reduced. The oligomer content is preferably less than 1500 ppm; preferably less than 1200 ppm; even more preferably below 1000 ppm.
The fibers obtained by using the propylene homopolymer also show increased tenacity and improved tactile feel.
The propylene homopolymers disclosed herein may be prepared by a process comprising polymerizing propylene with ethylene in the presence of a catalyst comprising the reaction product between:
(i) solid catalyst component comprising Ti, Mg, Cl and at least one electron donor compound, characterized in that it comprises, relative to the total weight of the solid catalyst component, from 0.1 to 50% by weight of Bi; the external donor is preferably an ester of glutaric acid, preferably an alkyl ester of glutaric acid, for example 13, 3-dipropylglutaric acid ester; preferably, esters of glutaric acid are used in a mixture with 9, 9-bis (alkoxymethyl) fluorenes such as 9, 9-bis (methoxymethyl) fluorene; preferably, the molar ratio between the ester of glutaric acid and the 9, 9-bis (alkoxymethyl) fluorene is from 50: 50 to 90: 10; preferably from 60: 40 to 80: 20; more preferably from 65: 35 to 75: 25; alkyl is C1-C10 alkyl, such as methyl, ethyl propyl; a butyl group; 1
(ii) An alkyl aluminum compound; and
(iii) an external electron donor compound having the general formula:
(R1)aSi(OR2)b
wherein R is1And R2Independently selected from alkyl groups having 1 to 8 carbon atoms, optionally containing heteroatoms, a is 0 or 1, and a + b ═ 4.
Preferably, in the catalyst component, the content of Bi is from 0.5 to 40 wt.%, more preferably from 1 to 35 wt.%, in particular from 2 to 25 wt.%, and in a very particular embodiment from 2 to 20 wt.%.
The particles of the solid component have a substantially spherical morphology and an average diameter of between 5 and 150 μm, preferably between 20 and 100 μm and more preferably between 30 and 90 μm. By particles having a substantially spherical morphology are meant those in which the ratio between the larger axis and the smaller axis is equal to or lower than 1.5, preferably lower than 1.3.
Generally, the amount of Mg is preferably 8 to 30 wt%, more preferably 10 to 25 wt%.
Generally, the amount of Ti is 0.5 to 5 wt%, more preferably 0.7 to 3 wt%.
The Mg/Ti molar ratio is preferably equal to or higher than 13, preferably from 14 to 40, more preferably from 15 to 40. Accordingly, the Mg/donor molar ratio is preferably higher than 16, more preferably higher than 17, generally from 18 to 50.
The Bi atoms are preferably derived from one or more Bi compounds having no double carbon bond. In particular, the Bi compound may be selected from Bi halides, Bi carbonates, Bi acetates, Bi nitrates, Bi oxides, Bi sulfates and Bi sulfides. Preferably wherein Bi has 3+A compound in a valence state. Among the Bi halides, preferred compounds are Bi trichloride and Bi tribromide. The most preferred Bi compound is BiCl3。
The preparation of the solid catalyst component can be carried out according to several methods.
According to one method, it is possible to prepare a compound of the formula Ti (OR)q-yXyWherein q is the valence of titanium and y is a number between 1 and q, preferably TiCl4) And is derived from MgCl2Magnesium chloride of an adduct of pROH(wherein p is a number between 0.1 and 6, preferably 2 to 3.5, and R is a hydrocarbon group having 1 to 18 carbon atoms) to prepare a solid catalyst component. By mixing the alcohol and the magnesium chloride, the adduct can be prepared in spherical form operating under stirring conditions at the melting temperature of the adduct (100-. The adduct is then mixed with an inert hydrocarbon immiscible with the adduct, thereby creating a rapidly quenched emulsion, resulting in solidification of the adduct in the form of spherical particles. Examples of spherical adducts prepared according to this procedure are described in USP 4,399,054 and USP 4,469,648. The adduct obtained can be directly reacted with the Ti compound or it can be previously submitted to thermal controlled dealcoholation (80-130 ℃) to obtain an adduct in which the number of moles of alcohol is generally lower than 3, preferably between 0.1 and 2.5. The reaction with the Ti compound can be carried out by suspending the adduct (dealcoholated or undecoholated) in cold TiCl4(usually 0 ℃) in a reaction vessel; the mixture is heated to 80-130 ℃ and held at this temperature for 0.5-2 hours. With TiCl4The treatment may be carried out one or more times. The electron-donor compound can be used in TiCl4Added in the required ratio during the treatment.
There are several methods available for adding one or more Bi compounds in the catalyst preparation. According to a preferred option, the Bi compound is incorporated directly into MgCl during its preparation2pROH adduct. In particular, the Bi compound can be prepared in the initial stage of the adduct preparation by reacting it with MgCl2And mixed with alcohol. Alternatively, it may be added to the molten adduct before the emulsification step. The amount of Bi introduced is from 0.1 to 1mol per mol of Mg in the adduct. Bound directly to MgCl2Preferred Bi compounds in the pROH adduct are Bi halides, in particular BiCl3。
The alkyl-Al compound (ii) is preferably chosen among the trialkyl aluminum compounds such as triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum. It is also possible to use alkylaluminum halides, alkylaluminum hydrides or alkylaluminum sesquichlorides, such as AlEt2Cl and Al2Et3Cl3Possibly in the form of a mixture with the above-mentioned trialkylaluminium. The Al/Ti ratio is higher than 1, generally between 50 and 2000.
The external electron donor compound (iii) is a silicon compound having the following general formula
(R1)aSi(OR2)b (II)
Wherein R is1And R2Independently selected from alkyl groups having 1 to 8 carbon atoms, optionally containing heteroatoms, wherein a is 0 or 1, and a + b ═ 4.
A first group of preferred silicon compounds of the formula (II) is that in which a is 1, b is 3 and R is1And R2Independently selected from those having alkyl groups of 2 to 6, preferably 2 to 4 carbon atoms, with Isobutyltriethoxysilane (iBTES) being particularly preferred.
Another preferred group of silicon compounds of the formula (II) is that in which a is 0, b is 4 and R is2Independently selected from those having alkyl groups of 2 to 6, preferably 2 to 4 carbon atoms, with tetraethoxysilane being particularly preferred.
The external electron donor compound (c) is used in an amount such that the molar ratio between the organoaluminum compound and said external electron donor compound (iii) is from 0.1 to 200, preferably from 1 to 100, more preferably from 3 to 50.
The polymerization process may be carried out according to known techniques, such as slurry polymerization using an inert hydrocarbon solvent as a diluent, or bulk polymerization using a liquid monomer (e.g., propylene) as a reaction medium. In addition, the polymerization process can be carried out in the gas phase operating in one or more fluidized or mechanically stirred bed reactors.
The polymerization is generally carried out at a temperature of from 20 to 120 ℃ and preferably from 40 to 80 ℃. When the polymerization is carried out in the gas phase, the operating pressure is generally between 0.5 and 5MPa, preferably between 1 and 4 MPa. In bulk polymerization, the operating pressure is generally between 1 and 8MPa, preferably between 1.5 and 5 MPa. Hydrogen is commonly used as a molecular weight regulator.
The fibers according to the invention may be stabilized fibers or spunbond fibers.
When spunlaid fibers are desired, propylene homopolymer can be visbroken to achieve the desired Melt Flow Rate (MFR). Visbreaking or controlled chemical degradation can be initiated with an appropriate amount of free radicals according to methods well known in the artAgents, preferably from 0.001 to 0.20wt3/4More preferably 0.05 to 0.1wt3/4Treating the precursor polypropylene. Preferably, the chemical degradation is carried out by contacting the polymeric material with at least one free radical initiator under high shear conditions at a temperature equal to or above the decomposition temperature of the free radical initiator. Preferred free radical initiators are peroxides having a decomposition temperature above 250 ℃, preferably from 150 ℃ to 250 ℃, such as di-tert-butyl peroxide, dicumyl peroxide, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexyne and 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexane (sold under the name Trigonox 101 or Luperox 101 by Akzo or Arkema, respectively).
The fibers of the present invention may also contain additives commonly used in the art, such as antioxidants, light stabilizers, heat stabilizers, nucleating agents, colorants, and fillers.
The fibers of the invention generally exhibit tenacity values at least equal to or higher than 20.0cN/tex, preferably higher than 25cN/tex, more preferably higher than 26 cN/tex.
In general, the titer of the fibers according to the invention is from 1 to 8dtex, preferably from 1.5 to 4.0 dtex.
The fibers of the present invention can be effectively spun at speeds typically higher than 3000m/min, preferably higher than 3300m/min, more preferably higher than 3500 m/min.
The fibers of the present invention can be spun at temperatures typically ranging from 200 ℃ to 300 ℃. Preferably, the spinning temperature is below 250 ℃, even more preferably, the spinning temperature is between 230 ℃ and 250 ℃.
The fibers of the present invention are useful in the manufacture of nonwoven fabrics having superior properties.
Such nonwoven fabrics may be produced by various methods, preferably by the well-known spunbond technique. Spunbonding is a nonwoven manufacturing technique in which a polymer is directly converted into endless filaments and randomly deposited to form a nonwoven material.
The following examples are given for the purpose of illustration and not for the purpose of limitation.
Examples
Characterization of
Xylene insoluble and soluble fraction at 25 ℃
The xylene soluble fraction was measured according to ISO 16152-; in the case of a solution volume of 250ml, precipitation was carried out at 25 ℃ for 20 minutes, 10 of which were solutions under stirring (magnetic stirrer) and dried at 70 ℃.
Acetone soluble fraction at 25 deg.C
Acetone (100ml) was added to the second aliquot of the filtered solution obtained according to the method for determining the xylene soluble fraction at 25 ℃ so that precipitation of the amorphous fraction occurred. The suspension was then filtered on teflon membrane coupled to a steel frit on a flask, dried in an oven at 80 ℃ overnight and weighed so that soluble and insoluble fractions can be determined.
Melt Flow Rate (MFR)
Unless otherwise stated, measurements were made according to ISO 1133 at 230 ℃ and under a load of 2.16 kg.
Filament titre
From 10cm long rovings 50 fibers were randomly selected and weighed. The total weight of 50 fibers, expressed in mg, was multiplied by 2 to obtain the titer, expressed in dtex.
Tenacity and elongation at break of the filaments
Segments of 100mm length were cut from 500m roving and individual fibers were randomly selected. Each individual fiber was fixed on the clamps of a dynamometer and drawn to break at a drawing speed of 20mm/min with an elongation of less than 100% and at a drawing speed of 50mm/min with an elongation of more than 100%, the initial distance between the clamps being 20 mm. The ultimate strength (load at break) and elongation at break were measured in the Machine (MD) direction.
Toughness is calculated by the following equation:
tenacity is ultimate strength (cN) × 10 per titer (dtex).
Maximum spinning speed
The maximum spinning speed gives an indication of the spinnability of the propylene polymer composition of the present invention. This value corresponds to the highest spinning rate that can be held for 30 minutes without filament breakage.
Soft touch
The softness index is a conventional measure of the softness of a fiber, calculated as the weight of the strand [1/g ], and its length measured under standard conditions. The softness values thus obtained are very consistent with the empirical test results of nonwovens. The equipment used for this analysis was as follows:
torsion measuring apparatus (Torcimetro of Negri e Bossi Spa)
Analytical balance (Mettler)
Softness tester (Clark).
The samples were prepared by providing fiber bundles having a linear density of about 4,000dtex and a length of 0.6 m. The end of the bundle was fixed to the grip of the twist measuring device and 120 twists were applied to the left. The twisted bundle was removed from the apparatus (taking care to avoid any untwisting). The two ends of the twisted bundle are on the same side and the two halves are wrapped around each other until the bundle assumes a stable form of cord. At least three specimens were prepared for each test. The bundle was bent in half with both ends fixed between the rollers of a Clark softness tester, the distance between the two halves being 1 cm. When the beam twists its bending direction, the plane of the device rotates to the right and stops, recording the rotation angle (α). Subsequently, when the beam twists its curved side, the plane rotates to the left and stops again. The rotation angle (b) is recorded. The height of the bundle above the two rollers is adjusted so that the sum a + -b is equal to 90 deg. +/-1 deg., and is measured with a suitable device (sensitivity 1 mm). Each of the two angles a and b should not exceed the limit of 45 +/-15. The bundle is removed from the device and cut to a height corresponding to the previously measured height. The cut beam was weighed with an analytical balance with an accuracy of 0.1 mg. The softness index can be calculated as follows: s.i. (1/W) × 100, where W is the weight of the cutting beam in grams. The final result is an average of 3 samples. The sensitivity for measuring the beam weight was 0.1 mg.
Melting temperature via Differential Scanning Calorimetry (DSC)
The melting point (Tm) of the polymer is measured by Differential Scanning Calorimetry (DSC) on a Perkin Elmer DSC-1 calorimeter, calibrated beforehand with respect to the indium melting point, according to ISO 11357-1, 2009 and 11357-3,2011, 20 ℃/min. The sample weight in each DSC crucible was kept at 6.0 ± 0.5 mg.
To obtain the melting point, the weighed sample was sealed in an aluminum pan and heated to 200 ℃ at 20 ℃/min. The sample was held at 200 ℃ for 2 minutes to completely melt all crystallites and then cooled to 5 ℃ at 20 ℃/minute. After standing at 5 ℃ for 2 minutes, the sample was heated to 200 ℃ for a second run at 20 ℃/min. In this second heating operation, the peak temperature (Tp, m) is set as the melting temperature.
Mg and Ti determination
The determination of the Mg and Ti content of the solid catalyst component was carried out by inductively coupled plasma emission spectroscopy on an "I.C.P Spectrometer ARL Accuris".
The sample was prepared by analytically weighing 0.1 ÷ 0.3 grams of catalyst and 2 grams of lithium metaborate/tetraborate 1/1 mixture in a "Fluxy" platinum crucible. After the addition of a few drops of KI solution, the crucible is inserted into a special apparatus "claise Fluxy" for complete combustion. With 5% v/v HNO3The residue was collected from the solution and then analyzed via ICP at the following wavelengths: magnesium, 279.08 nm; titanium, 368.52 nm.
Measurement of Bi
The determination of the Bi content in the solid catalyst component was carried out by inductively coupled plasma emission spectroscopy on an "I.C.P Spectrometer ARL Accuris".
By passing at 200cm3The samples were prepared by weighing 0.1-0.3 grams of catalyst in a volumetric flask. 10mL of 65% v/v HNO in two catalysts were slowly added3Solution and catalyst 50cm3The sample was digested for 4-6 hours in distilled water. The flask was then diluted to the mark with deionized water. The resulting solution was analyzed directly by ICP at the following wavelengths: bismuth, 223.06 nm.
Determination of the internal Donor content
The determination of the internal donor content in the solid catalytic compound was carried out by gas chromatography. The solid component was dissolved in acetone, an internal standard was added, and a sample of the organic phase was analyzed in a gas chromatograph to determine the amount of donor present in the starting catalyst compound.
Oligomer content
Determination of the oligomer content by solvent extraction involves the use of 10ml of methylene Chloride (CH) in an ultrasonic bath at 25 deg.C2Cl2) A5 g polypropylene sample was treated for 4 hours. Mu.l of the extracted solution was injected into a capillary column and analyzed by using FID without any filtration. To quantitatively estimate the oligomer content, calibration based on external standard methods has been applied. In particular, a series of hydrocarbons (C12-C22-C28-C40) are used.
Example 1 preparation of a homopolymer
Preparation of the spherical adduct
Microspheroidal MgCl was prepared according to the procedure described in comparative example 5 of WO98/440092·pC2H5OH adducts, except that BiCl in powder form is added before the oil is fed3And an amount of 3 mol% with respect to magnesium.
Step of preparation of solid catalyst component
300ml of TiCl are introduced at room temperature under a nitrogen atmosphere into a 500ml round-bottom flask equipped with a mechanical stirrer, cooler and thermometer4. After cooling to 0 ℃, 9.0g of the spherical adduct (prepared as described above) was added with stirring and then diethyl 3, 3-dipropylglutarate was added to the flask in that order. The amount of charged internal donor is such that the Mg/donor molar ratio is 13. The temperature was raised to 100 ℃ and held for 2 hours. After this time, the stirring was stopped, the solid product was allowed to settle and the supernatant liquid was siphoned off at 100 ℃.
After siphoning, fresh TiCl was added4And 9, 9-bis (methoxymethyl) fluorene in an amount to produce a Mg/diether molar ratio of 13. The mixture was then heated at 120 ℃ and held at this temperature for 1 hour with stirring. The stirring was again stopped, the solid was allowed to settle and the supernatant liquid was siphoned off. The solid was washed six times with anhydrous hexane in a temperature gradient down to 60 ℃ and once at room temperature. The solid obtained was then dried under vacuum and analyzed.
Prepolymerization treatment
Before introducing it into the polymerization reactor, the above solid catalyst component was contacted with Triethylaluminum (TEAL) and Isobutyltriethoxysilane (iBTES) as described in table 1.
Polymerisation
The polymerization run was carried out in a continuous mode in a liquid phase loop reactor. Hydrogen is used as a molecular weight regulator. The polymerization conditions are shown in table 1.
Comparative example 2
Comparative example 2 was carried out as in example 1, except that 9, 9-bis (methoxymethyl) fluorene was used in an equimolar amount instead of diethyl 3, 3-dipropylglutarate so that the catalyst contained the same total molar amount of internal donor of 1 as the catalyst of example 1.
Polymerization conditions are indicated in Table 1
Thereafter, the polymer granules were mixed with the usual stabilizing additive composition in a twin-screw extruder Berstorff ZE 25 (screw length/diameter ratio: 34) and extruded under a nitrogen atmosphere under the following conditions:
rotating speed: 250 rpm;
the output of the extruder: 15 kg/hour;
melting temperature: 245 ℃.
The stabilizing additive composition is prepared from the following components:
-0.1% by weight1010；
-0.1% by weight168；
-0.04% by weight of DHT-4A (hydrotalcite);
all percentage amounts refer to the total weight of the polymer and the stabilizing additive composition.
The above-mentioned1010 is 2, 2-bis [3- [, 5-bis (1, 1-dimethylethyl) -4-hydroxyphenyl) -1-oxopropoxy]Methyl radical]1, 3-propanediyl-3, 5-bis (1, 1-dimethylethyl) -4-hydroxyphenyl-propionate, and168 is tris (2, 4-di-tert-butylphenyl) phosphite. The properties associated with the polymer compositions are reported in table 2.
TABLE 1 polymerization conditions
Example 1
Comparative example 2
TEAL/catalyst (wt ratio)
5.7
6.0
TEAL/external donor (wt ratio)
606
600
Temperature of
75
75
Pressure bar
28.0
28.0
H2/C3-mol/mol
0.0057
0.0042
Remarking: c3 ═ propylene.
The characteristics of the polymers of example 1 and comparative example 2 are reported in table 2.
TABLE 2
Comparative example 3 is HP2619, a propylene homopolymer for fiber sold by LyondellBasell
Preparation of fibers
The polymer was extruded in a Leonard 25 spinning test line with a screw L/D ratio of 5. This line is sold by Costrozioni Meccaniche Leonard-Sumirago (VA). The operating spinning conditions are reported here.
The operating conditions are as follows:
pore diameter: mm0.4
Number of holes in the stamp: 41
Mold temperature (. degree. C.): 280
The properties of the filaments are recorded in table 3.
TABLE 3
Example 1:
comparative example 2
Comparative example 3
Maximum spinning speed
m/min
4200
3900
4200
Fiber titer
dTex
1,75
1,75
1,75
Toughness
cN/Tex
25,6
24,6
23
Elongation at break
％
415
400
390
m/min
2250
2250
2250
Maximum rotation speed
m/min
4200
3900
4200
During spinning, the smoke generated by the homopolymer of example 1 is negligible relative to the smoke generated by the homopolymers of comparative examples 2 and 3.
In addition, the resulting fiber of example 1 was better in elongation at break and tenacity.
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