阅读说明：本技术 纤维用聚烯烃组合物 (Polyolefin composition for fibers ) 是由 M·加尔万 C·卡瓦列里 J·马蒂波尔奎雷斯 R·勒迈尔 R·德帕洛 于 2018-06-20 设计创作，主要内容包括：相对于纤维总重量，聚烯烃纤维包括2wt％?20wt％的聚烯烃组合物，所述聚烯烃组合物包括：A)5?35wt％的丙烯均聚物或丙烯乙烯共聚物；B)25?50wt％的乙烯和C<Sub>3</Sub>?C<Sub>8</Sub>α?烯烃的共聚物，其包含0.1?20wt％的α?烯烃单元；以及C)30?60wt％的乙烯和丙烯的共聚物，其含有25?75wt％的乙烯单元。(Polyolefin fibers comprising from 2% to 20% by weight, relative to the total weight of the fibers, of a polyolefin composition comprising: A)5 to 35 wt% of a propylene homopolymer or a propylene ethylene copolymer; B)25-50 wt% of ethylene and C 3 ‑C 8 α -olefin copolymers comprising from 0.1 to 20% by weight of α -olefin units, and C) from 30 to 60% by weight of copolymers of ethylene and propylene containing from 25 to 75% by weight of ethylene units.)

1. Polyolefin fiber comprising from 2% to 20% by weight, relative to the total weight of the fiber, of a polyolefin composition comprising:

A)5 to 35 wt% of a propylene homopolymer or a propylene ethylene copolymer containing 90 wt% or more of propylene units; component A) contains 10% by weight or less of a fraction soluble in xylene at 25 ℃ (XS)_A) Amount of propylene units and fraction XS_AAll based on the weight of A);

B)20-50 wt%; ethylene and C₃-C₈α -olefin copolymer comprising 0.1-20 wt% of α -olefin units and containing 25 wt% or less, a fraction soluble in xylene at 25 ℃ (XS)_B) α amount of olefin units and partial XS_BBased on the weight of (B); and

C) 30-60% by weight of a copolymer of ethylene and propylene comprising 25-75% by weight of ethylene units and comprising 40-95% by weight of a fraction soluble in xylene at 25 ℃ (XS)_C) Amount of ethylene units and fraction XS_CBased on the weight of (C);

(A) the amounts of (A), (B) and (C) are based on the total weight of (A) + (B) + (C), i.e. the total amount of (A) + (B) + (C) is 100.

2. The polyolefin fiber of claim 1, comprising 5 wt% to 15 wt% of the polyolefin composition.

3. The polyolefin fiber of claim 1 or 2, further comprising 98 wt% to 80 wt%; propylene homo-or copolymer D) having a fraction soluble in xylene at 25 ℃ of less than 10 wt%, the sum of the polyolefin composition and the propylene homo-or copolymer being 100 wt%.

4. Polyolefin fibres according to any of claims 1 to 3, wherein component D) is a propylene homopolymer or a propylene copolymer containing from 0.5% to 10% by weight of ethylene or C₄-C₈α -olefin derived units.

5. Polyolefin fiber according to any of claims 1 to 4 wherein component D) is a propylene homopolymer.

6. Polyolefin fiber according to any of claims 1 to 5, wherein component A) is a polypropylene homopolymer

7. Polyolefin fibres according to any of claims 1 to 6, wherein component B) is ethylene and C₃-C₈α -olefin copolymer comprising 5 to 15 wt% of α -olefin units.

8. Polyolefin fibres according to any of claims 1 to 7 in which component C) is a copolymer of ethylene and propylene containing from 37 to 65% by weight of ethylene units.

9. Polyolefin fibre according to any of claims 1-8 wherein component (A) has a melt flow rate (ISO1133, 230 ℃/2.16kg) of 50-200g/10 min;

10. polyolefin fibres according to any of claims 1 to 9 wherein component (B) has a melt flow rate (ISO1133, 230 ℃/2.16kg) of from 0.1 to 70g/10 min;

11. the polyolefin fiber of any of claims 1-01, wherein the polyolefin composition has a melt flow rate (ISO1133, 230 ℃/2.16kg) of 0.5-25g/10 m;

12. polyolefin fibres according to any of claims 1 to 11 in which component D) has a melt flow rate (ISO1133, 230 ℃/2.16kg) of from 7 to 50g/10 min.

13. Polyolefin fibres according to any of claims 1 to 12 in which component D) has a melt flow rate (ISO1133, 230 ℃/2.16kg) of from 12 to 40g/10 min.

14. Polyolefin fibres according to any of claims 1 to 13 wherein component D) is a propylene ethylene copolymer.

15. Polyolefin fibres according to any of claims 1 to 13 wherein component D) is a blend containing from 1.0% to 6.0% by weight of ethylene or C₄-C₈α -propylene copolymers of olefin derived units.

Technical Field

The present disclosure relates to fibers comprising polyolefin compositions that include beneficial embodiments such as high softness.

Background

Polyolefin fibers, particularly polypropylene fibers, are well known in the art, particularly for the production of nonwoven fabrics.

WO 94/009193 relates to a polymer composition for producing polypropylene fibres, comprising a polypropylene homopolymer of the type used for producing heat-sealable fibres and a modified polymer composition comprising:

A) 10-60% by weight of a propylene polymer having an isotacticity index (percentage by weight of the fraction insoluble in boiling n-heptane) higher than 80,

B)3 to 25% by weight of an ethylene-propylene copolymer insoluble in xylene at 23 ℃, and

C) 15-87% by weight of a propylene copolymer insoluble in xylene at 23 ℃, the concentration of said modified polymer composition being lower than 20% by weight of the total weight.

Use of the composition to improve softness and toughness of nonwoven fabrics

However, there is a need in the art to provide polyolefin compositions for use as modifiers to increase the balance of fiber properties, particularly in terms of tenacity, elongation at break, and softness.

Disclosure of Invention

Applicants have found that compositions comprising a propylene-based polymer and a Linear Low Density Polyethylene (LLDPE) are useful as soft modifiers in polyolefin compositions for fibers. Such soft modifiers can be used in small amounts to increase the softness of the resulting fibers by keeping tenacity and elongation substantially unchanged.

Accordingly, the present disclosure relates to a polyolefin fiber comprising, with respect to the total weight of the fiber, from 2% to 20% by weight of a polyolefin composition comprising:

A)5 to 35 wt% of a propylene homopolymer or a propylene ethylene copolymer containing 90 wt% or more of propylene units; component A) contains 10% by weight or less of a fraction soluble in xylene at 25 ℃ (XS)_A) Amount of propylene units and fraction XS_AAll based on the weight of A);

B)20-50 wt%; ethylene and C₃-C₈α -olefin copolymer comprising 0.1-20 wt% of α -olefin units and containing 25 wt% or less, a fraction soluble in xylene at 25 ℃ (XS)_B) α amount of olefin units and partial XS_BBased on the weight of (B); and

C) 30-60% by weight of a copolymer of ethylene and propylene comprising 25-75% by weight of ethylene units and comprising 40-95% by weight of a fraction soluble in xylene at 25 ℃ (XS)_C) Amount of ethylene units and fraction XS_CBased on the weight of (C);

(A) the amounts of (A), (B) and (C) are based on the total weight of (A) + (B) + (C), i.e. the total amount of (A) + (B) + (C) is 100.

Detailed Description

Accordingly, the present disclosure relates to a polyolefin fiber comprising, with respect to the total weight of the fiber, from 2% to 20% by weight of a polyolefin composition comprising:

A)5-35 wt%; preferably 10-30 wt%; more preferably 15 to 23 wt% of a propylene homopolymer or a propylene ethylene copolymer containing 90 wt% or more preferably 95 wt% or more; preferably 97 wt% or more propylene units; component A) contains 10 wt.% or less, preferably 8 wt.% or less, more preferably 6 wt.% or less, even more preferably 5 wt.% or less of a fraction soluble in xylene at 25 ℃ (XS)_A) Amount of propylene units and fraction XS_AAll based on the weight of A);

B)20-50 wt%; preferably 25 to 45 wt%; more preferably 30-40 wt% of ethylene and C₃-C₈α -copolymers of olefins containing from 1.0 to 20% by weight, preferably from 5% to 15% by weight, more preferably from 6% to 15% by weight, still more preferably from 7% to 12% by weight of α -olefin units and containing 25% by weight or less, preferably 20% by weight or less, preferably 17% by weight or less of a fraction soluble in xylene at 25 ℃ (XS)_B) α amount of olefin units and partial XS_BBased on the weight of (B); and

C)30-60 wt%; preferably 35-55 wt%; more preferably 40 to 50 wt% of a copolymer of ethylene and propylene containing 25 to 75 wt%; preferably 37 to 65 wt.%(ii) a More preferably from 45% to 58% by weight of ethylene units and containing from 40% to 95% by weight of a fraction soluble in xylene at 25 ℃ (XS)_C) Amount of ethylene units and fraction XS_CBased on the weight of (C);

(A) the amounts of (A), (B) and (C) are based on the total weight of (A) + (B) + (C), i.e. the total amount of (A) + (B) + (C) is 100.

The melt flow rate (230 ℃/2.16kg) of component (A) is preferably from 50 to 200g/10 min; more preferably 80-170g/10 min.

The melt flow rate (ISO1133, 230 ℃/2.16kg) of the components (A) + (B) blended together is from 0.1 to 70g/10 min. Preferably 1-50g/10 min; more preferably 8-40g/10 min.

Preferably component B) has a density (determined according to ISO1183 at 23 ℃) of 0.940 to 0.965g/cm³. Component B) is a copolymer containing C₃-C₈α -ethylene copolymers of olefin derived units specific examples of such α -olefin comonomers are propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene, 1-butene, 1-hexene and 1-octene being preferred, 1-butene being most preferred.

Preferably, the polyolefin composition has a melt flow rate (ISO1133, 230 ℃/2.16kg) of from 0.5 to 25g/10min, preferably from 0.8 to 20.0g/10 min; even more preferably 1.0-18.0g/10 min.

Preferably, the xylene soluble fraction of the polyolefin composition has an intrinsic viscosity [ η ] at 25 ℃ (measured in tetrahydronaphthalene at 135 ℃) of 1.5 to 4.0dl/g, preferably an intrinsic viscosity of 2.0 to 3.5dl/g, more preferably an intrinsic viscosity of 2.1 to 2.8 dl/g.

For the purposes of this disclosure, the term "copolymer" includes only polymers containing two comonomers, such as propylene and ethylene or ethylene and 1-butene.

The polyolefin fibers comprise from 2% to 20% by weight, preferably from 3% to 15% by weight, relative to the total weight of the fibers; more preferably from 4% to 12% by weight, of the polyolefin composition, exhibit increased softness by keeping the values of tenacity and elongation at break substantially unchanged with respect to the fibers without the polyolefin composition. Thus, soft fibers having good mechanical properties can be obtained.

It has been found that the polyolefin composition can be prepared by sequential polymerization comprising at least three sequential steps, wherein components (a), (B) and (C) are prepared in separate subsequent steps, operating in each step except the first step in the presence of the polymer formed and the catalyst used in the previous step. Adding catalyst only in the first step; however, its activity is such that it remains active for all subsequent steps.

The polymerization, which may be continuous or batch, is carried out according to known techniques and is carried out in liquid phase, in the presence or absence of an inert diluent, or in gas phase, or by liquid-gas mixing techniques. Preference is given to carrying out the polymerization in the gas phase.

The reaction time, pressure and temperature with respect to the polymerization step are not critical, but it is preferable that the temperature is 50 to 100 ℃. The pressure may be atmospheric or higher.

The molecular weight is regulated by using known regulators, in particular hydrogen.

The polymerization is preferably carried out in the presence of a Ziegler-Natta catalyst. Typically, Ziegler-Natta catalysts comprise the reaction product of an organometallic compound of group 1, 2 or 13 of the periodic Table of the elements with a transition metal compound of groups 4 to 10 of the periodic Table of the elements (new notation). In particular, the transition metal compound may be selected from compounds of Ti, V, Zr, Cr and Hf, and is preferably supported on MgCl₂The above.

Particularly preferred catalysts comprise said organometallic compound of group 1, 2 or 13 of the periodic Table of the elements and a catalyst comprising a compound supported on MgCl₂A reaction product of the above solid catalyst component of a Ti compound and an electron donor compound.

Preferred organometallic compounds are alkylaluminum compounds.

Thus, in a preferred embodiment, the polymer composition B) of the invention can be prepared by using a Ziegler-Natta polymerization catalyst, more preferably supported on MgCl₂The above ziegler-natta catalyst, even more preferably a ziegler-natta catalyst comprising the reaction product of:

1) a solid catalyst component comprising a Ti compound and MgCl supported thereon₂Electron donor (internal electron donor) of (i);

2) an alkylaluminum compound (cocatalyst); and optionally also,

3) an electron donor compound (external electron donor).

The solid catalyst component (1) comprises, as electron donors, compounds generally selected from ethers, ketones, lactones, compounds containing N, P and/or S atoms, and esters of mono-and dicarboxylic acids.

Catalysts having the above characteristics are well known in the patent literature; particularly advantageous are the catalysts described in U.S. Pat. No. 4,399,054 and European patent 45977.

Particularly suitable among the electron donor compounds are phthalic acid esters, preferably diisobutylphthalate, and succinic acid esters.

Suitable succinic acid esters are represented by formula (I):

wherein the radical R₁And R₂Identical or different from each other, is C optionally containing heteroatoms₁-C₂₀Linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl; radical R₃To R₆Are identical or different from each other and are hydrogen or C optionally containing heteroatoms₁-C₂₀Radicals R which are linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl radicals, and are bound to the same carbon atom₃To R₆May be joined together to form a ring.

R₁And R₂Preferably C₁-C₈Alkyl, cycloalkyl, aryl, arylalkyl and alkylaryl. Particularly preferred is where R₁And R₂A compound selected from primary alkyl groups, in particular branched primary alkyl groups. Suitable R₁And R₂Examples of radicals are methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, 2-ethylhexyl. Is particularly preferredEthyl, isobutyl and neopentyl are preferred.

One of the preferred groups of compounds described by formula (I) is that wherein R₃To R₅Is hydrogen and R₆Are compounds having branched alkyl, cycloalkyl, aryl, arylalkyl and alkylaryl groups having from 3 to 10 carbon atoms. Another preferred group of compounds of formula (I) is that wherein R₃To R₆At least two groups of (A) are different from hydrogen and are selected from C optionally containing heteroatoms₁-C₂₀Linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl compounds. Particular preference is given to compounds in which two radicals different from hydrogen are attached to the same carbon atom. Furthermore, wherein at least two groups different from hydrogen are attached to different carbon atoms, i.e. R₃And R₅Or R₄And R₆The compounds of (4) are also particularly preferred.

Other particularly suitable electron donors are 1, 3-diethers, as shown in published European patent applications EP-A-361493 and 728769.

As cocatalyst (2), preference is given to using trialkylaluminum compounds, such as triethylaluminum, triisobutylaluminum and tri-n-butylaluminum.

The electron-donor compounds (3) which can be used as external electron-donors (added to the alkylaluminum compound) include aromatic acid esters (e.g. alkyl benzoates), heterocyclic compounds (e.g. 2, 2,6, 6-tetramethylpiperidine and 2, 6-diisopropylpiperidine), in particular silicon compounds containing at least one Si-OR bond (where R is a hydrocarbon radical).

Examples of said silicon compounds are of the formula R_a ¹R_b ²Si(OR³)_cWherein a and b are integers from 0 to 2, c is an integer from 1 to 3 and the sum (a + b + c) is 4; r¹、R²And R³Is an alkyl, cycloalkyl or aryl group having 1 to 18 carbon atoms optionally containing heteroatoms.

A useful example of a silicon compound is (tert-butyl)₂Si(OCH₃)₂(cyclohexyl) (methyl) Si (OCH)₃)₂, (phenyl)₂Si(OCH₃)₂And (cyclopentyl)₂Si(OCH₃)₂。

The aforementioned 1, 3-diethers are also suitable as external donors. In case the internal donor is one of said 1, 3-diethers, the external donor can be omitted.

The catalyst may be precontacted with a small amount of olefin (prepolymerization), maintained in suspension in a hydrocarbon solvent, and polymerized at a temperature ranging from room temperature to 60 ℃ to produce a polymer in an amount of 0.5 to 3 times the weight of the catalyst.

The operation can also be carried out in liquid monomer, in which case the amount of polymer produced is up to 1000 times the weight of the catalyst.

The fibers of the present disclosure preferably comprise 98 wt% to 80 wt%; preferably from 95% to 85% by weight, more preferably from 92% to 88% by weight, of a propylene homo-or copolymer D) having a fraction soluble in xylene at 25 ℃ of less than 10% by weight, preferably less than 8% by weight, more preferably less than 4% by weight, the sum of the polyolefin composition and the propylene homo-or copolymer being 100% by weight. Preference is given to using the propylene homopolymer D).

The propylene copolymer D) preferably contains from 0.5% to 10.0% by weight, preferably from 1.0% to 6.0% by weight; more preferably from 1.5% to 4.5% by weight of ethylene or C₄-C₈α -olefin derived units specific examples of such α -olefin comonomers are propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene, preferably ethylene, 1-butene or 1-hexene, most preferably ethylene.

The melt flow rate (ISO1133, 230 ℃/2.16kg) of the propylene homo-or copolymer D) is preferably from 7 to 50g/10min, preferably from 12 to 40g/10 min; even more preferably 15-30g/10 min.

The following examples are given for the purpose of illustration and are not intended to limit the invention.