EP3481882A1

EP3481882A1 - Shoe uppers

Info

Publication number: EP3481882A1
Application number: EP17742658.2A
Authority: EP
Inventors: Antonio Angelo RUSSO; Lionel DE BEAUFFORT
Original assignee: Solvay Specialty Polymers Italy SpA
Current assignee: Solvay Specialty Polymers Italy SpA
Priority date: 2016-07-07
Filing date: 2017-07-04
Publication date: 2019-05-15
Also published as: JP2019523043A; KR20190024951A; US20200221825A1; WO2018007359A1; CN109476810A

Abstract

The present invention relates to an upper for a footwear article, said upper comprising at least one panel having at least one layer made from a composition comprising a fluorinated thermoplastic polyurethane polymer.

Description

Shoe uppers

Cross-reference to related applications

This application claims priority from European application No. 16178295.8 filed on 7^th July 2016, the whole content of this application being incorporated herein by reference for all purposes.

Technical Field

Background Art

Uppers for footwear articles are generally formed by stitching together a plurality of exterior panel sections. These exterior panel sections can be made of several materials, such as natural and leather, plastic, mesh and non-woven fabrics.
“Non-woven fabrics” are defined as fabric-like materials made from long fibers, bonded together by chemical, mechanical, heat or solvent treatment. The term is used in the textile manufacturing industry to denote fabrics, such as felt, which are neither woven nor knitted. Typically, the long fibers consists of hydrogenated thermoplastic polymers, notably based on hydrogenated urethane (H-TPU).
H-TPU polymers have been disclosed in the art for the manufacturing of the upper part of shoes, for example in US 20100186874 PUMA AKTIENGESELLSCHAFT RUDOLF DASSLER SPORT , US 2013/0169219 PUMA SE and US 2014/0082961 REEBOK INTERNATIONAL LIMITED .
Heat processable elastomeric polyurethanes comprising (per)fluoropoly- ether blocks were disclosed for example in US 5332798 AUSIMONT S.P.A. .

Summary of invention

The Applicant perceived the need of providing a new polymeric material that can be useful for the manufacture of the upper of footwear articles, notably shoes and boots, characterized by having improved properties when compared to hydrogenated thermoplastic polyurethane polymers (TPU). More in particular, the Applicant focused on providing a polymeric material having improved resistance to stain, improved chemical and wear resistance, low temperature flexibility, silky feel while maintaining good mechanical properties.
Thus, in a first aspect, the present invention relates to an upper, for a footwear article, comprising at least one panel having at least one layer [layer E] made from a composition [composition (C)] comprising at least one fluorinated polyurethane [F-TPU polymer], said F-TPU polymer comprising recurring units derived from:
[monomer (a)] at least one diol selected from the group comprising poly-ether type diol, poly-ester type diol, polybutadien-diol and polycarbonate-diol;
[monomer (b)] at least one hydroxy-terminated (per)fluoropolyether polymer [PFPE polymer] ;
[monomer (c)] at least one aromatic, aliphatic or cycloaliphatic diisocyanate; and
[monomer (d)] at least one aliphatic, cycloaliphatic or aromatic diol having from 1 to 14 carbon atoms.
Preferably, said panel comprises layer E as single layer
Preferably, said panel comprises layer E as the outermost layer.
The Applicant has surprisingly found that when layer E is the outermost layer, it provides a soft silky feeling to the touch, without the addition of plasticizer agents to said composition (C).
In addition, the Applicant surprisingly found that when layer E is the outermost layer, the panel shows improved resistance to stain and an increased ease of cleaning, when compared to panels made from hydrogenated thermoplastic polyurethane (H-TPU) polymers.

Description of embodiments

For the purposes of the present description and of the following claims:
- the term “(per)fluoropolyether” is intended to indicate a “fully or partially fluorinated polyether";
- the expression “(per)fluoropolyoxyalkylene chain” is intended to indicate a partially or fully fluorinated, straight or branched, polyoxyalkylene chain;
- the use of parentheses before and after symbols or numbers identifying compounds, chemical formulae or parts of formulae has the mere purpose of better distinguishing those symbols or numbers from the rest of the text and hence said parentheses can also be omitted;
- the term "upper" (also referred to as “vamp”) is intended to indicate the part of a footwear article (such as shoes, boot and the like) that covers the toes, the top of the foot, the sides of the foot, and the back of the heel, and is attached to the outsole of the footwear article;
- the term “panel” is intended to indicate the part(s) that form(s) the upper. The upper can be manufactured using only one panel or joining together more than one panels. When more two or more panels are joined together to form the upper, the panels can be selected from for example the toe box, the toe cap, the quarter, the vamp, the tongue, the counter and the back strap of a footwear.
Preferably, said F-TPU polymer is a block copolymer, i.e. a polymer comprising blocks (also referred to as “segments”), each block comprising recurring units deriving from at least one monomer (a), at least one monomer (b), at least one monomer (c) and at least one monomer (d), as defined above.
Preferably, said F-TPU polymer has an average number molecular weight of from 30,000 to about 70,000 Da.
Preferably, said F-TPU polymer has a melting point (T_m) of from about 120°C to about 240°C.
Preferably, said at least one monomer (a) has an average number molecular weight of from 500 to 4,000 Da, more preferably of from 1,000 to 4,000.
Preferably, said at least one monomer (a) is selected in the group comprising, more preferably consisting of, poly(ethylene)glycol, poly(propylene)glycol, poly(tetramethylen)glycol (PTMG), poly(1,4-butanediol)adipate, poly(ethandiol-1,4-butanedio) adipate, poly(1,6-hexandiol-neopentyl)glycol adipate, poly-caprolactone-diol (PCL) and polycarbonate-diol.
Poly(tetramethylen)glycol, poly-caprolactone-diol and polycarbonate-diol being particularly preferred.
Preferably, said at least one monomer (b) is a hydroxy-terminated (per)fluoropolyether polymer [PFPE polymer], i.e. a polymer comprising a (per)fluoropolyoxyalkylene chain [chain (R_pf)] having two chain ends, wherein one or both chain ends terminates with at least one -OH group.
Preferably, at least one chain end of said chain (R_pf) terminates with a group of formula:
-CH₂(OCH₂CH₂)_t-OH (I)
wherein
t is 0 or from 1 to 5.
More preferably, both chain ends of said chain (R_pf) terminate with a group of formula (I) as defined above.
Preferably, said chain (R_pf) is a chain of formula
-O-D-(CFX^#)_z1-O(R_f)(CFX^*)_z2-D*-O-
wherein
z1 and z2, equal or different from each other, are equal to or higher than 1; X^# and X*, equal or different from each other, are -F or -CF3, provided that when z1 and/or z2 are higher than 1, X^# and X* are -F;
D and D*, equal or different from each other, are an alkylene chain comprising from 1 to 6 and even more preferably from 1 to 3 carbon atoms, said alkyl chain being optionally substituted with at least one perfluoroalkyl group comprising from 1 to 3 carbon atoms;
(R_f) comprises, preferably consists of, repeating units R°, said repeating units being independently selected from the group consisting of:
(i) -CFXO-, wherein X is F or CF₃;
(ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF₃, with the proviso that at least one of X is –F;
(iii) -CF₂CF₂CW₂O-, wherein each of W, equal or different from each other, are F, Cl, H;
(iv) -CF₂CF₂CF₂CF₂O-;
(v) -(CF₂)_j-CFZ-O- wherein j is an integer from 0 to 3 and Z is a group of general formula -O-R_(f-a)-T, wherein R_(f-a) is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the following : -CFXO- , -CF₂CFXO-, -CF₂CF₂CF₂O-, -CF₂CF₂CF₂CF₂O-, with each of each of X being independently F or CF₃ and Tbeing a C₁-C₃ perfluoroalkyl group.
More preferably, chain (R_f) is selected from the following formulae (R_f-a) to (R_f-c):
(R_f-a) -(CF₂O)_n(CF₂CF₂O)_m(CF₂CF₂CF₂O)_p(CF₂CF₂CF₂CF₂O)_q-
wherein m, n, p, q are 0 or integers selected in such a way as chain R_f meets the above number average molecular weight requirement, with the proviso that if, p and q are simultaneously 0, n is not 0; when m is other than 0, the m/n ratio is preferably between 0.1 and 20; when (m+n) is other than 0, (p+q)/(m+n) is preferably between 0 and 0.2;
(R_f-b) -(CF₂CF(CF₃)O)_a(CF₂CF₂O)_b(CF₂O)_c(CF(CF₃)O)_d-
wherein a, b, c, d are 0 or integers selected in such a way as chain R_f meets the above number average molecular weight requirement; with the proviso that, at least one of a, c and d is not 0; when b is other than 0, a/b is preferably between 0.1 and 10; when (a+b) is different from 0 (c+d)/(a+b) preferably is between 0.01 and 0.5, more preferably between 0.01 and 0.2;
(R_f-c) -(CF₂CF(CF₃)O)_e(CF₂O)_f(CF(CF₃)O)_g-
wherein e, f, g are 0 or integers selected in such a way as chain R_fmeets the above number average molecular weight requirement; when e is other than 0, (f+g)/e is preferably between 0.01 and 0.5, more preferably between 0.01 and 0.2.
PFPE polymers wherein chain (R_f) complies with formula (R_f-a) as defined above, wherein p and q are 0, are particularly preferred in the present invention.
In a preferred embodiment, said PFPE polymer complies with the following formula (PFPE-I):
HO-(CH₂CH₂O)_t-CH₂-(R_pf)-CH₂(OCH₂CH₂)_u-OH (PFPE-I)
wherein
t and u are, each independently, 0 or from 1 to 5; and
R_pf is as defined above.
Preferably, said PFPE polymer has an average number molecular weight of from 400 to 10,000 Da, more preferably from 1,000 to 5,000.
In a preferred embodiment, the molar ratio between monomers (a) and monomers (b) is from 2 to 20, more preferably from 2 to 10.
In a preferred embodiment, the amount of monomers (b) is such that the F-TPU polymer comprises from 4 to 30 wt.% of fluorine.
Preferably, said at least one monomer (c) has a number molecular weight of 500 Da or lower, preferably from 10 to 500 Da.
Preferably, said at least one monomer (c) is selected in the group comprising, preferably consisting of, 4,4’-methylene-diphenylene-di- isocyanate (MDI), 1,6-hexan-diisocyanate (HDI), 2,4-toluene-diisocyanate, 2,6-toluene-diisocyanate, xylilen-diisocyanate, naphthalene-diisocyanate, paraphenylen-diisocyana- te, hexamaethylen-diisocyanate, isophorone-diisocyanate, 4,4’-dicyclohexyl-methane-diisocyanate and cyclohexyl-1,4-diisocyanate.
MDI and HDI being particularly preferred.
Preferably, said at least one monomer (d) is selected in the group comprising, preferably consisting of, ethylene-glycol, 1,4-butanediol (BDO), 1,6-hexane diol (HDO), N,N-diethanolamine and N,N-diisopropanolaniline.
BDO and HDO being particularly preferred.
In a preferred embodiment, the sum of blocks deriving from monomers (c) and (d) is from 10 to 60 wt.% based on the total weight of the F-TPU polymer.
Those skilled in the art would readily understand that blocks comprising recurring units derived from monomers (a) and (b) are rubber-like blocks, while blocks comprising recurring units derived from monomers (c) and (d) are hard blocks.
In a preferred embodiment, at least 80% of the blocks comprising recurring units derived from said monomers (b) [blocks B] are linked, at least one of their ends, to a block comprising recurring units derived from monomers (a) [blocks A] through a block comprising recurring units derived from monomers (c) [blocks C].
In other words, at least 80% of blocks B are contained in a sequence of the following type: -[A-C-B-C]-.
Advantageously, the F-TPU polymer can be prepared following the procedures disclosed in US 5332798 AUSIMONT S.P.A. , in particular in Example 15.
According to a preferred embodiment, the upper is made from a composition (C) that is free of plasticizer agents.
Preferably, said composition (C) comprises the F-TPU polymer as defined above as the main component.
More preferably, said F-TPU polymer is in an amount of at least 60 wt.%, more preferably at least 80 wt. %, even more preferably at least 85 wt. % based on the total weight of said composition (C).
In addition to the F-TPU polymer, said composition (C) can optionally comprise further additives, such as for example antioxidants, thermal stabilizers, dyestuffs and fillers.
Embodiments wherein said composition (C) is essentially made of said F-TPU polymer in combination with an amount of up to 1 wt.% of any of the additives listed above are also encompassed by the present invention.
According to a first embodiment, said upper comprises a plurality of panels stitched together, each panel comprising a layer E as defined above.
According to an alternative embodiment, said upper comprises one single panel, which extends for the entire surface of the upper and comprises a layer E as defined above. Uppers comprising one single panel are also known as “unitary upper design”.
Layer E can be manufactured following methods known in the art, for example by melt-blown process as disclosed in US 2010/0186874 cited above
As an example, layer E can be manufactured by a process comprising the following steps:
(i) providing a mould;
(ii) filling said mould with a composition comprising at least one elastomeric fluorinated polyurethane [F-TPU polymer] as defined above;
(iii) sealing the mould;
(iv) heat treating the sealed mould; and
(v) extracting the article from the mould.
Preferably, step (iv) comprises two steps, wherein the first step comprises heating at a first temperature for a time from 10 seconds to 10 minutes and the second step comprises heating at a second temperature, said second temperature being lower than said first temperature, for a time of from 30 seconds to 24 hours.
More preferably, said first temperature is from 120°C to 300°C.
More preferably, said second temperature is from 50°C to 200°C.
Alternatively, step (iv) comprises only one step of heating at a temperature of from 50°C to 300°C for a time of from 10 seconds to 24 hours.
Preferably, after step (iv) and before step (v), the mould is allowed to cool down.
According to a preferred embodiment, said at least one panel comprises layer E as the only layer.
According to another preferred embodiment, said at least one panel comprises layer E as defined above and at least one texture layer [layer T] consisting of texture yarns.
For example, according to an embodiment, the upper according to the present invention comprises at least one panel comprising layer E as defined above, said layer E having an external surface and an internal surface, wherein at least a part of said internal surface is connected with a texture layer [layer T] consisting of texture yarns.
According to another embodiment, the upper according to the present invention comprises at least one panel comprising layer E as defined above and two layers T consisting of texture yarns, wherein layer E is interposed between two layers T.
When the upper comprises layer E and layer(s) T, the upper is obtained by welding together layer E and layer(s) T.
The welding can be performed for example using a high-frequency welding process or an ultrasonic sound welding process.
In a further embodiment, the present invention relates to a footwear article comprising an upper as defined above.
Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.
The invention will be herein after illustrated in greater detail by means of the Examples contained in the following Experimental Section; the Examples are merely illustrative and are by no means to be interpreted as limiting the scope of the invention.

Experimental part

Materials
- Monomers (a):
(a1) CAPA^TM 2201 (from Perstorp) polycaprolactone-diol (PLC) having molecular weight (Mw) of about 2,000 and -OH value of about 56 mg KOH/g;
(a2) polytetramethyleneglycol (PTMEG) having Mw of about 2,000
(a3) ETERNACOLL^® UH200 (from UBE) polycarbonate-diol (PCD) having Mw of about 2,000
(a4) BESTER^TM (from DOW) polyester-diol having Mw of about 2,000
- Monomers (b) having formula:
H(OCH₂CH₂)_pOCH₂CF₂O(CF₂CF₂O)_m(CF₂O)_nCF₂CH₂O(CH₂CH₂O)_pH
(b1) p=4.7 and Mw of about 2,000
(b2) p=1.6 and Mw of about 1,700
- Monomers (c):
(c1) diphenylen-4,4’-diisocyanate (MDI)
(c2) 1,6-hexan-diisocyanate (HDI)
- Monomers (d):
(d1) 1,4-butanediol (BDO)
(d2) 1,6-hexandiol (HDO)
- Catalyst:
bismuth neodecanoate
Preparation of F-TPU polymer specimens – method A
F-TPU polymer specimens 1 to 4 in the form of sheet were prepared starting from the abovementioned monomers following the same procedure detailed in Example 15 of US 5,332,798 (to Ausimont S.p.A.) cited above.
F-TPU polymers thus obtained contained 20 wt.% of recurring units derived from monomers (b).
Preparation of F-TPU polymer specimens – method B
F-TPU polymer specimens 5 to 7 and 8 (the latter as comparison) in the form of sheet were prepared as follows:
- the hydrogenated pre-polymer was synthetized by reacting monomer (c) and monomer (a) in the equivalent ratio 2 to 1, at a temperature of 90°C;
- the fluorinated pre-polymer was synthetized by reacting monomer (c) and monomer (b) in the equivalent ratio 2 to 1, at a temperature of 90°C;
- the hydrogenated pre-polymer and the fluorinated pre-polymer were then mixed together and stirred at 90°C for 30 minutes;
- monomer (c) was further added depending on the selected stoichiometry;
- the reaction was continued at 90°C for 3 minutes until chain-extension was completed;
- the polymer thus obtained was casted at 100°C for 24 hours.
The compositions of the F-TPU polymers obtained following methods A and B described above and the compositions of comparative hydrogenated polyurethane polymers (H-TPU) are reported in the following Table 1.

As further comparison, a commercially available hydrogenated TPU (H-TPU 9*) was used. The monomers ratio for H-TPU 9* is not publicly available.

Table 1

	Monomers (ratio by mol)
	a1	a2	a3	a4	b1	b2	c1	c2	d1	d2
F-TPU 1	0.8	-	-	-	0.2	-	2.0	-	1.0	-
F-TPU 2	-	0.7	-	-	0.3	-	3.0	-	2.0	-
F-TPU 3	-	0.6	-	-	-	0.4	2.5	-	1.5	-
F-TPU 4	-	-	-	0.75	0.25	-	-	2.0	-	1.0
F-TPU 5	0.75	-	-	-	-	0.25	-	3.0	2.0	-
F-TPU 6	-	-	0.75	-	-	0.25	-	2.0	1.0	-
F-TPU 7	4.0	-	-	-	-	0.3	-	0.7	3.0	-
H-TPU 8(*)	-	1.0	-	-	-	-	2.0	-	1.0	-
H-TPU 9(*)	n/a	-	-	-	-	-	-	n/a	n/a	-

(*) comparison
n/a = value not available

The mechanical properties of sheets made from F-TPU and H-TPU polymers were evaluated and the results are reported in Table 2.

Table 2

	Shore A	Tensile strength (MPa)	Elongation at break (%)
F-TPU 1	85	28.1	471
F-TPU 2	93	31	410
F-TPU 3	80	35	400
F-TPU 4	75	7.30	590
F-TPU 5	90	26.1	505
F-TPU 6	83	13	550
F-TPU 7	91	31.8	506
H-TPU 8(*)	78	40	550

(*) comparison
The above results show that the F-TPU polymers according to the present invention have mechanical properties comparable with the mechanical properties of H-TPU polymers typically used in the production of the upper of footwear articles, and hence F-TPU polymers provide good mechanical properties to the finished upper.
The sheets were used in the Examples described hereinafter.
Example 1 – Contact angle
This test is considered to be predictive for both stain and chemical resistance.
The static contact angle (SCA) of a sessile drop (about 5 μL) of water and n-hexadecane as solvents was measured with the DSA30 instrument (Krüss GmbH, Germany). The SCA values as well as standard deviations were calculated among ten contact angles.
Surface free energy (SFE) was calculated following the Owens, Wendt, Rabel and Kaelble method (WORK method), which is a standard method for calculating the surface free energy of a solid from the contact angle with several liquids.

The results are summarized in the following Table 3.

Table 3

Sample	SCA H₂O	SCA C₁₆	SFE (mN/m)
F-TPU 1	104	64.5	16.1
F-TPU 2	110.5	63.6	15.09
F-TPU 3	106.7	62.9	15.90
F-TPU 4	86	61	23.6
F-TPU 5	105	68	14.9
F-TPU 6	103	66	16
F-TPU 7	98	70	16.9
H-TPU 8(*)	77	46	30.93
H-TPU 9(*)	81	29	31.7

(*) comparison
SCA = Static Contact Angle
H₂O = water
C₁₆ = hexadecane
SFE = Surface Free Energy
The above results show that the contact angle measured with both water (H₂O) and hexadecane (C₁₆) increased while the surface energy dropped down to the range from 15 to 16 mN/m compared to 31 mN/m for the hydrogenated thermoplastic polyurethane used as reference compound. These data are consistent with an increase in terms of stain resistance and chemical resistance conferred by the F-TPU polymers compared to H-TPU polymers.
Example 2 – Blue denim test
This test is considered to be predictive for both staining and abrasion resistance.
The test was performed with the instrument Taber Industries 5750 Linear Abraser, that was set to run at the following conditions:
- cycle speed: 30 cycles/min
- stroke length: 2.54 cm (1 inch)
- number of cycles: 200
- total load: 1 kg.
Tests were performed once with dry denim and once with wet denim on F-TPU 1, F-TPU 2, F-TPU 3, F-TPU 5 and F-TPU 7.
Before performing the test with wet denim, denim was submerged in water for 10 second, then it was removed and water was squeezed out by hand so that denim did not drip but was wet to the touch.
The tests were performed as follows: a denim sample measuring approximately 30 mm x 30 mm was fixed to a fixture in order to prevent shifting of the sample during the test. A sample of each F-TPU and of H-TPU was then placed on the denim sample and fixed to the fixture as well.
Checkpoints were set as follows:
- after rub and
- after cleaning with isopropyl-alcohol (IPA).
Results for the dry test: no stain was observed for F-TPU 1, F-TPU 2, F-TPU 3, F-TPU 5 and F-TPU 7.
Results for the wet test: a very light halo was observed for F-TPU 1, F-TPU 2, F-TPU 3, F-TPU 5 and F-TPU 7.
Example 3 – Stain test
A drop of each staining agent listed above was put into contact with the surface of a specimen made from F-TPU 1 and let for 24 hours at ambient conditions. The specimen was then cleaned with water.
A specimen made from H-TPU was used as comparison and treated as disclosed above.

The results are summarized in the following Table 4, wherein:
++ = no stain
+ = mark/halo
- = stain

Table 4

Staining agent	H-TPU(*)	F-TPU 1
Olive oil	-	++
Ketchup	+	++
Hot coffee	-	+
Mayonaise	-	++
Coca Cola	-	++
Mustard	-	+
Vinager	++	++
Windex^® cleaner	+	+
Formula 409^® cleaner	+	+
Purell^® hand sanitizer	-	++
Vaseline intensive care lotion	-	++
Alcohol	-	++

(*) comparison
The above results clearly showed the increase in term of both stain and chemical resistance of the F-TPU specimen compared to the H-TPU specimen.
Example 4 – Evaluation of haptic properties
The haptic properties (notably the feeling of softness) of F-TPUs and the H-TPUs were measured by testing the sheets of the materials subjectively by hand feel of 5 individuals.
Soft feel was measured subjectively by hand touch and rated on a scale from 1 to 5, with 1 being poor soft feel (hard feel) and 5 being excellent soft feel. Participants took part in this study individually, so they did not influence each other in their responses. Participants were presented with the four samples in a random order and asked to feel and rate them.

The results are summarized in the following Table 5.

Table 5

Sample	Rating
Sample	Individual 1	Individual 2	Individual 3	Individual 4	Individual 5	Average
F-TPU 1	4	5	4	4	5	4.4
F-TPU 2	5	5	5	4	5	4.8
F-TPU 3	5	4	4	4	4	4.2
F-TPU 4	5	5	5	4	5	4.8
F-TPU 5	5	4	4	3	4	4.0
F-TPU 6	5	4	5	4	4	4.4
F-TPU 7	4	4	4	4	5	4.2
H-TPU 8(*)	2	1	1	1	2	1.4
H-TPU 9(*)	2	2	1	1	2	1.6

(*) comparison
The above results clearly showed that the sheets obtained with the F-TPUs according to the present invention showed better haptic properties, notably improved feeling of softness, when compared to sheets obtained from H-TPU polymers.

Claims

An upper, for a footwear article, comprising at least one panel having at least one layer [layer E] made from a composition [composition (C)] comprising at least one fluorinated polyurethane [F-TPU polymer], said F-TPU polymer comprising recurring units derived from:

[monomer (a)] at least one diol selected from the group comprising poly-ether type diol, poly-ester type diol, polybutadien-diol and polycarbonate-diol;

[monomer (b)] at least one hydroxy-terminated (per)fluoropolyether polymer [PFPE polymer];

[monomer (c)] at least one aromatic, aliphatic or cycloaliphatic diisocyanate; and

[monomer (d)] at least one aliphatic, cycloaliphatic or aromatic diol having from 1 to 14 carbon atoms.
The upper according to claim 1, wherein said at least one monomer (a) is selected in the group comprising poly(ethylene)glycol, poly(propylene)glycol, poly(tetramethylen)glycol (PTMG), poly(1,4-butanediol)adipate, poly(ethandiol-1,4-butanedio) adipate, poly(1,6-hexandiol-neopentyl)glycol adipate, poly-caprolactone-diol (PCL) and polycarbonate-diol.
The upper according to claim 1 or 2, wherein said at least one monomer (b) is a hydroxy-terminated PFPE polymer comprising a (per)fluoropolyoxyalkylene chain [chain (R_pf)] having two chain ends, wherein one or both chain ends terminates with at least one -OH group.
The upper according to claim 3, wherein at least one chain end of said chain (R_pf) terminates with a group of formula (I):

-CH₂(OCH₂CH₂)_t-OH (I)

wherein

t is 0 or from 1 to 5.
The upper according to claim 3, wherein both chain ends of said chain (R_pf) terminate with a group of formula (I):

-CH₂(OCH₂CH₂)_t-OH (I)

wherein

t is 0 or from 1 to 5.
The upper according to any one of claims 3 to 5, wherein said chain (R_pf) is a chain of formula

-O-D-(CFX^#)_z1-O(R_f)(CFX^*)_z2-D*-O-

wherein

z1 and z2, equal or different from each other, are equal to or higher than 1; X^# and X*, equal or different from each other, are -F or -CF3, provided that when z1 and/or z2 are higher than 1, X^# and X* are -F;

D and D*, equal or different from each other, are an alkylene chain comprising from 1 to 6 and even more preferably from 1 to 3 carbon atoms, said alkyl chain being optionally substituted with at least one perfluoroalkyl group comprising from 1 to 3 carbon atoms;

(R_f) comprises, preferably consists of, repeating units R°, said repeating units being independently selected from the group consisting of:

(i) -CFXO-, wherein X is F or CF₃;

(ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF₃, with the proviso that at least one of X is –F;

(iii) -CF₂CF₂CW₂O-, wherein each of W, equal or different from each other, are F, Cl, H;

(iv) -CF₂CF₂CF₂CF₂O-;

(v) -(CF₂)_j-CFZ-O- wherein j is an integer from 0 to 3 and Z is a group of general formula -O-R_(f-a)-T, wherein R_(f-a) is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the following : -CFXO- , -CF₂CFXO-, -CF₂CF₂CF₂O-, -CF₂CF₂CF₂CF₂O-, with each of each of X being independently F or CF₃ and Tbeing a C₁-C₃ perfluoroalkyl group.
The upper according to claim 6, wherein said chain (R_f) is selected from the following formulae (R_f-a) to (R_f-c):

(R_f-a) -(CF₂O)_n(CF₂CF₂O)_m(CF₂CF₂CF₂O)_p(CF₂CF₂CF₂CF₂O)_q-

wherein m, n, p, q are 0 or integers selected in such a way as chain R_f meets the above number average molecular weight requirement, with the proviso that if, p and q are simultaneously 0, n is not 0; when m is other than 0, the m/n ratio is preferably between 0.1 and 20; when (m+n) is other than 0, (p+q)/(m+n) is preferably between 0 and 0.2;

(R_f-b) -(CF₂CF(CF₃)O)_a(CF₂CF₂O)_b(CF₂O)_c(CF(CF₃)O)_d-

wherein a, b, c, d are 0 or integers selected in such a way as chain R_f meets the above number average molecular weight requirement; with the proviso that, at least one of a, c and d is not 0; when b is other than 0, a/b is preferably between 0.1 and 10; when (a+b) is different from 0 (c+d)/(a+b) preferably is between 0.01 and 0.5, more preferably between 0.01 and 0.2;

(R_f-c) -(CF₂CF(CF₃)O)_e(CF₂O)_f(CF(CF₃)O)_g-

wherein e, f, g are 0 or integers selected in such a way as chain R_fmeets the above number average molecular weight requirement; when e is other than 0, (f+g)/e is preferably between 0.01 and 0.5, more preferably between 0.01 and 0.2.
The upper according to any one of the preceding claims, wherein said PFPE polymer complies with the following formula (PFPE-I):

HO-(CH₂CH₂O)_t-CH₂-(R_pf)-CH₂(OCH₂CH₂)_u-OH (PFPE-I)

wherein

t and u are, each independently, 0 or from 1 to 5; and

R_pf is as defined in claim 6.
The upper according to any one of the preceding claims, wherein said at least one monomer (c) is selected in the group comprising 4,4-methylene-diphenylene-di-isocyanate (MDI), 1,6-hexan-diisocyanate (HDI), 2,4-toluene-diisocyanate, 2,6-toluene-diisocyanate, xylilen-diisocyanate, naphthalene-diisocyanate, paraphenylen-diisocyanate, hexamethylen- diisocyanate, isophorone-diisocyanate, 4,4-dicyclohexyl-methane-diisocyanate and cyclohexyl-1,4-diisocyanate.
The upper according to any one of the preceding claims, wherein said at least one monomer (d) is selected in the group comprising ethylene-glycol, 1,4-butanediol (BDO), 1,6-hexane diol (HDO), N,N-diethanolamine and N,N-diisopropanolaniline.
The upper according to any one of the preceding claims, wherein at least 80% of the blocks [blocks B] comprising recurring units derived from said monomer (b) are linked, at least one of their ends, to a block [block A] comprising recurring units derived from said monomer (a) through a block [block C] comprising recurring units derived from said monomer (c).
The upper according to any one of the preceding claims, wherein said composition (C) is free of plasticizer agents.
The upper according to any one of the preceding claims, wherein said composition (C) comprises said F-TPU polymer in an amount of at least 60 wt.% based on the total weight of said composition (C).
The upper according to any one of the preceding claims, wherein said panel comprises layer E as outermost layer.
A footwear article comprising an upper according to any one of claims 1 to 14.