AU2002352212A1 - Method for making propylene monofilaments, propylene monofilaments and their use - Google Patents

Description

DECLARATION I ....... Lo. o... . . . .... ...................................................................................... -of...- -. .; ; .. ,'-7/Se. . R - ....... . .. R O i S ii ....... ........ .... ......................................................... Q j i E .................................................... CERE oD RECHERCHES DE YON. Bp2 do solemnly and sincerely declare: F. 69192 SAINT-FONS CEDEX 1. That I am well acquainted with both the English and French languages, and 2. That the attached document is a true and correct translation of the specification accompanying the application for patent made in International Application No. PCT/EPO2/13649 filed on 3 December 2002. AND I make this declaration conscientiously believing the statement contained herein to be true in every particular. SIG NED this ....... ,-1 ................. day of .... .. ... 9 .0. ...... .'G. o ............................................ SIGNEDthis(Signature) (Signature) (12) DEMANDE INTERNATIONALE PUBLIEE EN VERTU DU TRAiTE DE COOPERATION EN MATItRE DE BREVETS (PCT) (19) Organisation Mondiale de la Proprit6 Intellectuelle Bureau international IIIllllllli Illlllllllllllllll 111 11111 1 llll lllIIIIIll (43) Date de la publication internationale (10) Numr6ro de publication internationale 12 juin 2003 (12.06.2003) PCT W O 03/048434 Al (51) Classification internationale des brevets' : D01F 6/46, (81) ttats d6sign6s (national): AE, AG, AL, AM, AT, AU, AZ, 6/06, 1/10 BA, BB, BG, BR, BY, BZ, CA, CH, CN, CO, CR, CU, CZ, DE, DK, DM, DZ, EC, EE, ES, FI, GB, GD, GE, GH, GM, (21) Num6ro de la demande internationale: HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, PCT/EPO2/13649 LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, OM, PH, PL, PT, RO, RU, SC, SD, SE, SG, (22) Date de d6p6t international : SK, SL, TJ, TM, TN, TR, TIT, TZ, UA, UG, US, UZ, VC, 3 dicembre 2002 (03.12.2002) VN, YU, ZA, ZM, ZW. (25) Langue de d~p~t: frangais (25) Langue de dpt: fna (84) Etats designs regionall) : brevet ARIPO (GH, GM, KE, (26) Languede publication franais LS, MW, MZ, SD, SL, SZ, TZ, UG, ZM, ZW), brevet eurasien (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), brevet (30) Donaes relatives A la priority : europden (AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FIL ( 200 1 rli 2216/01 5a dcembr 21FR, GB, GR, IE, IT, LU, MC, NL, PT, SE, SI, SK, TR), 2001 2216/01 5 d6cembre 2001 (05.12.2001) CH brevet OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, (71) D6posant (pour tous les Etats ddsignds sauf US) : RHO- M, MR, NE, SN, TD, TG). DIA INDUSTRIAL YARNS AG [CH/CH]; 6021 Emmen brticke, CH-6021 EMMENBROCKE (CH). Publi6e : - avec rapport de recherche internationale (72) Inventeur; et - avant I'expiration du ddlaiprivu pour la modification des S(75) Inventeur/Ddposant (pour US seulement) : SCHfJTZE, revendications, sera republide si des modifications sont S Gustav [CHICH]; Tignuppa, CH-7014 TRIN (CH). reques (74) Mandataire : ESSON, Jean-Pierre; RHODIA SER- En ce qui concerne les codes 6 deux lettres et autres abrivia VICES, Direction de la Propri6t6 Industrielle, Centre de tions, se rdfirer aux "Notes explicatives relatives aux codes et Recherches de Lyon BP62, F-SAINT FONS CEDEX abrdviations"figurant au ddbut de chaque numdro ordinaire de 69192 (FR). la Gazelltte du PCT (54) Title: METHOD FOR MAKING PROPYLENE MONOFILAMENTS, PROPYLENE MONOFILAMENTS AND THEIR USE (54) Titre: PROCEDE DE FABRICATION DE MONOFILAMENTS DE POLYPROPYLENE, MONOFILAMENTS DE POLY SPROPYLENE ET LEUR UTILISATION (57) Abstract: The invention concerns a method for making propylene monofilaments having a 230 'C/2.16 kg melt flow index (MFI) from 2 to 16 g/10 min, having a diameter larger than 0 .050 mm and improved abrasion resistance, which consists in adding to the polypropylene 20 to 0.1 wt. % of an additive upstream of the extruder, spinning the molten material in a water bath, drawing : Sit and winding it. The invention also concerns a polypropylene monofilament having a 230 *C/2.6 kg melt flow index (MFI) from 2 to 16 g/10 min, having a diameter greater than 0.050 mm and improved abrasion resistance, exhibiting a strength of at least 50 cN/tex, for an elongation corresponding to the maximum tensile stress (elongation at rupture) of at least 30 %. Furthermore, it has an abrasion of less than 0.05 % and a relative tensile energy absorption > 100 % after being treated for 24 hours at 120 *C. ,f) (57) Abr6g6 : Dans on proc&d6 de fabrication de monofilaments d'un polypropylene pr6sentant un indice de viscosity en fondu (MFI) 230 *C/2,16 kg de 2 16 g/10 min, poss6dant on diamhtre sup6rieur A 0,050 mm et une resistance A l'abrasion am61ior6e, on ajoute au polypropylIne 20 0,1% en poids d'un additif en amont de l'extmdeuse, on file la matihre fondue dans on bain d'eau, on l'6tire et on la bobine.Le monofilament d'un polypropylene pr6sentant un indice de viscosity en fondu (MFI) 230 'C/2,16 kg de 2 k 16 g/10 min, poss6dant un diametre sup6rieur A 0,050 mm et une resistance A l'abrasion amlior6e, prdsente une resistance d'au Smoins 50 cN/tex, pour un allongement correspondant A l'effort de traction maximal (allongement A la rupture) de moins de 30 %. Il pr6ente par ailleurs une abrasion de moins de 0,05 % et une 6nergie de rupture relative > 100% aprts traitement de 24 heures A 120

'C.

1 PROCESS FOR MANUFACTURING POLYPROPYLENE MONOFILAMENTS, POLYPROPYLENE MONOFILAMENTS AND THEIR USE The invention relates to a process for 5 manufacturing monofilaments of a polypropylene having a melt flow index (MFI) at 2300C/2.16 kg of 2 to 16 g/10 min and possessing a diameter of greater than 0.050 mm and an improved abrasion resistance; it also relates to monofilaments of this polypropylene and to their use. 10 Two-dimensional polypropylene textile articles are of great interest as chemically and mechanically resistant filtration means for filtering in the chemical, pharmaceutical and food industries. In this field, relatively coarse monofilaments, possessing 15 a diameter of greater than 0.050 mm, are most particularly required. Pure polypropylene monofilaments have the drawback of forming a great deal of dust because of the low abrasion resistance of this substance during the 20 weaving process. The problem of abrasion is also known in the case of other thermoplastics. Thus, EP-A2-0 784 107 cites melt-spun monofilaments, of polyamide, polyester or polypropylene, that are intended for the forming fabrics of paper machines and 25 for the wires of edge cutters. According to that patent, abrasion-resistant monofilaments are obtained using 70 to 99% by weight of a fibre-forming polymer and 1 to 30% by weight of a maleic-anhydride-modified 2 polyethylene/polypropylene rubber, and other additives. However, the examples are limited, as regards the fibre-forming polymer, to the polyamide nylon-6 and to polyethylene terephthalate, as well as a PA-6,6/PA-6 5 copolyamide. The spinning rates are not specified. Also known, from EP-A-1 059 370, is a process for manufacturing polypropylene multifilaments intended for textile applications. A metallocene-catalysed isotactic polypropylene is used as starting material, 10 the melt flow index of the polypropylene having to be greater than 19 g per 10 minutes if it is desired to achieve the desired shrinkage characteristics. This is because, to obtain a low shrinkage, high MFI values are necessary. The above patent describes fully oriented 15 yarns (FOYs) of 10 dpf (denier per filament) [0.03953 mm] and partially oriented yarns (POY) of 2 dpf (denier per filament) [0.01768 mm]. As regards the yarns manufactured, only general indications are given. There is no description of monofilaments. 20 The problem of the invention consists in providing an economic process for manufacturing coarse abrasion-resistant polypropylene monofilaments. Another problem of the invention consists in manufacturing coarse polypropylene monofilaments that exhibit 25 improved abrasion resistance during weaving. Yet another problem consists in providing the use of coarse monofilaments, possessing good abrasion resistance, for manufacturing two-dimensional high- 3 performance articles, especially those intended for filtration. The problems are solved according to the invention by the fact that 20 to 0.01% by weight of an 5 additive is added to the polypropylene upstream of the extruder, the melt is spun into a water bath, drawn into monofilaments and the monofilaments are wound up. As polypropylene, it is preferred to use a homopolymer possessing a melt flow index of more than 10 2 g/10 min, preferably from 6 to 13 g/10 min, in particular from 12 to 13 g/10 min. An MFI of more than 16 g/10 min has the drawback of giving insufficient mechanical properties and poor abrasion resistance. It is appropriate to use an additive 15 consisting of a combination of lubricant, filler and heat stabilizer. As combination of lubricant, filler and heat stabilizer, 0.5 to 1.2% by weight of polyethylene waxes, calcium carbonate and sterically hindered phenols have proved to be particularly 20 suitable. In another embodiment, it is appropriate to use as additive 0.05 to 1.0% by weight, in particular 0.3 to 1.0% by weight, of a lubricant. Particularly suitable, as lubricant, are metal salts of carboxylic 25 acids, linear or branched hydrocarbons, fluoroelastomers and polydimethylsiloxanes. In yet another embodiment, it is appropriate to use fillers as additive. As fillers, 0.01 to 0.1% by 4 weight of aerosils and 0.1 to 1.0% by weight of calcium carbonate have proved to be particularly suitable. In yet another embodiment, it is appropriate to use as additive 0.1 to 0.8% by weight of a heat 5 stabilizer. Sterically hindered phenols, phosphites and phosphonites have proved to be particularly suitable. In yet another embodiment, it is appropriate to use as additive 1 to 20% by weight of a polypropylene/polyethylene copolymer possessing a 10 melting point 140 0 C. It is appropriate that the monofilaments possess a strength of at least 50 cN/tex for an elongation corresponding to the maximum tensile stress (elongation at break) of less than 35%, preferably less 15 than 30%. This is because a strength of less than 50 cN/tex has the drawback of increasing the number of yarn breakages during the weaving process. It is also important for the monofilaments to exhibit less than 0.05% abrasion. This is because when 20 the abrasion is greater than 0.05%, irregularities occur during weaving, these being due to the reeds becoming fouled too quickly. This means that the interval between cleaning operations must be shortened, thereby reducing the productivity of the loom. 25 It is appropriate for the monofilaments to be characterized by a relative fracture energy > 100% after treatment for 24 hours at 120 0 C, in particular after oven ageing. This has the advantage of increasing 5 the lifetime of the filters, when they are subjected to a relatively high thermal stress and to aggressive chemicals. The monofilaments according to the invention 5 are particularly suitable for the manufacture of two dimensional articles intended for filtration in the chemical, pharmaceutical and food industries. The invention will now be described in greater detail with the aid of examples. 10 Polymers As fibre-forming polymers, five different commercially available polypropylenes were used in the tests, these having a melt flow index (MFI) at 230 0 C/2.16 kg varying 15 from 6.0 to 13.0 g/10 min. Each time, 50 kg of polypropylene granules were blended, using 100 kg drums and an eccentric mixer. The blending was carried out using two different processes, depending on the additive. The various processes will be explained in 20 the examples. The granules/additive blend was fed directly into the extruder and melted. Spinning conditions: Extruder: diameter: 40 mm; barrel length: L/D = 25 extruder pressure: 80 bar 25 output: 19.76 kg/h 5 heating zones; Spinning pump: swept volume: 10 cm 3 /revolution; Spinning unit: electrical heating; 6 Metering pump: 23.19 rpm; Dies: diameter: 0.7 mm length of the capillary: 3 x D; Water bath: die/water bath distance: 45 mm 5 temperature: 30 0 C. Drawing stages and heating channels Drawing stage 1: 7 rolls; roll diameter: 230 mm; 1 heating channel Drawing stage 2: 7 rolls: roll diameter: 230 mm; 1 heating channel Drawing stage 3: 7 rolls; roll diameter: 230 mm; 2 heating channels Drawing stage 4: 4 rolls; roll diameter: 230 mm. Spinning preparation: 5% aqueous solution. 10 Preparation of the specimens: Examples 2, 5, 6 and 7. In the case of the pulverulent additives, such as the fillers, lubricant, heat stabilizer, etc., the process 15 starts by rolling the granules for half an hour in an adhesive, such as BAYSILON M 100® (brand name of Bayer AG), then the rest of the additives are added and blended for a further 1.5 hours.

7 Example 4: In the case of modified polyolefins, the blend of granules, consisting of polypropylene and PP/PE modified polyolefin, having a melting point > 140 0 C, 5 were blended for one hour. The examples are given in Table 1.

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- -. .. . 04 P W u C- o~ a C; 4 a) ) H4 Q H 4H ) -H4 C) 0 J1 az&MJ (d U) Q- Q.1-H1-H -H -H 4 Q 0-1 4 r -40~ ES-H: 0o 00000 000 04-J --------- ----------------- L4 m1 Nl~-l- r-rAH3 F, M - m 0. . . . . . co M M M f~fr- com m m ) a) - H 0 4-JOr ) 44 (1) 4 () 000 00 0 O Ola)r ~ H - m Jo m r-04 H04C)00 C 00 r- -- 44 - >iC > 4r-I H .r-4Hr-iC CO-C) 0 C) CD 0>>--->> 4-) (y M n 000 00 00 -4 W Eou U) W 0 0H(1) --- 4 Q a)) (L ) a 1 ) Q r-I JC'1 Lf - r- 0q LO0 l 0 4 44-3 4U) 4)U 4U4-J 04 0404 .Hx Cddd ~ ~ Cd(L 0-d0 qd Cd Q 4- ( ) a)0 ) G ) Q ) q 0 r-q -1 r- r-i - 4 q - 9 To allow more detailed explanations, the results have been shown graphically and photographically. These show: 5 - Figure 1, a histogram indicating the specific fracture energy, the oven ageing and the abrasion with and without the addition of an additive according to Example 2; - Figure 2, the specific fracture energy, oven 10 ageing and abrasion behaviour with and without the addition of an additive according to Example 4; - Figure 3a, the abrasion behaviour without the addition of an additive as a function of the yardage manufactured, according to Example 1 (control example); 15 and - Figure 3b, the abrasion behaviour with the addition of an additive and as a function of the yardage manufactured, according to Example 8 (embodiment example). 20 In Figure 1, the pair of columns on the left represent the specific fracture energy, that in the middle the oven ageing and that on the right the abrasion, with and without the addition of an additive according to Example 2. The columns on the left reflect 25 the prior art, those on the right represent the results obtained with the monofilaments according to the invention. This figure shows, as regards the abrasion, an improvement of more than 100%. Now, 100% less 10 abrasion means that the loom can operate for at least twice as long before it has to be cleaned. Similar results are obtained for the relative fracture energy. In this case, the right-hand column of the pair of 5 columns in the middle also shows an improvement, by more than 50%. The specific fracture energy, indicated by the right-hand column of the pair of columns on the left, also shows an improvement over the prior art. Figure 2 differs from Figure 1 by the fact 10 that it shows the abrasion with and without the addition of an additive according to Example 4. Figure 3a shows photographs indicating the state of the reeds of a loom after manufacturing 100 m, 200 m and 300 m of fabric from pure polypropylene 15 monofilament [control trial (Example 1)]. The fouling by polypropylene fluff after 300 m is so great that the loom had to be stopped. Figure 3b shows photographs indicating the state of the reeds of a loom after manufacturing 100 m, 20 200 m and 300 m of fabric from the monofilament according to the invention [illustrative example (Example 8)]. Even after manufacturing 300 m of fabric, the amount of fluff produced remains less than that obtained for 100 m in the control example. 25 Measurement methods: * Melt flow index according to ASTM D1238; 11 * Linear density determined according to SN 197 012 and SN 197 015, supplemented by DIN 53830; * Calculation of the mechanical constant MC from the following formula: 5 MC= . -F [cN/tex where D denotes the elongation in % and F denotes the strength in cN/tex. Description of the abrasion tests: 10 Manufacture of the sectional beams. The sectional beams, each of 1000 m, were manufactured using monofilaments from 80 bobbins of the various embodiments. 15 Weaving trials: The weaving trials were carried out on a ribbon loom. Maximum possible production: 4000 rpm; The shed was formed by cams; Working mode: without weft reentry; 20 Warp yarn density: 22.80 yarns/cm; Reed: opening, 0.175 mm dent thickness: 0.264 mm dent width: 7.0 mm; Rotation speed of the loom: 1000 rpm; 25 Weaving speed: 10 m/h; Weave: L1/l sheet cloth. Evaluation of the abrasion behaviour: 12 - visual assessment of the reeds; - gravimetric determination of the amount of fluff produced. For the visual examination, the reeds were 5 photographed after the operating time for 100 m, 200 m and preferably 300 m, and they were assigned a rating. Evaluation of the abrasion behaviour using the gravimetric method is described below. To do this, all of the fluff formed is collected after the 10 operating time for 300 m, it is weighed and related to the weight of the warp yarns using the following formula: amount deposited in % = mass of fluff deposited x 100 number of warp yams x length of the warp yams x linear density 10,000 The monofilaments according to the invention, 15 possessing a diameter 0.050 mm, are suitable for manufacturing, without abrasion, fabrics intended for filtration. By virtue of the process according to the invention and the monofilament according to the 20 invention, it has become possible for the first time to weave, practically without any abrasion, a polypropylene monofilament and to considerably increase the operating time of the loom. This monofilament is particularly suitable for the manufacture of fabrics 25 used for filtration in the chemical, pharmaceutical and food industries.

Claims (10)

1. Process for manufacturing monofilaments of a polypropylene having a melt flow index (MFI) at 5 230°C/2.16 kg of 2 to 16 g/10 min and possessing a diameter of greater than 0.050 mm and an improved abrasion resistance, characterized in that from 20 to 0.01% by weight of an additive is added to the polypropylene upstream of the extruder, the melt is 10 spun into a water bath, drawn into monofilaments and the monofilaments are wound up.

2. Process according to Claim 1, characterized in that 0.5 to 1.2% by weight of a combination of lubricant, filler and heat stabilizer is 15 used as additive.

3. Process according to Claim 1, characterized in that 0.05 to 1% by weight of a lubricant is used as additive.

4. Process according to Claim 1, 20 characterized in that 0.01 to 1.0% by weight of fillers is used as additive.

5. Process according to Claim 1, characterized in that 0.1 to 0.8% by weight of a heat stabilizer is used as additive. 25

6. Process according to Claim 1, characterized in that 1 to 20% by weight of a polypropylene/polyethylene copolymer possessing a melting point ! 140 0 C is used as additive. 14

7. Monofilaments of a polypropylene having a melt flow index (MFI) at 230 0 C/2.16 kg of 2 to 16 g/10 min and possessing a diameter of greater than 0.050 mm and an improved abrasion resistance, 5 characterized by a strength of at least 50 cN/tex for an elongation corresponding to the maximum tensile stress (elongation at break) of less than 35%, preferably less than 30%.

8. Monofilaments according to Claim 7, 10 characterized by an abrasion of less than 0.05%.

9. Monofilaments according to Claim 7, characterized by a relative fracture energy > 100% after treatment for 24 hours at 120 0 C.

10. Use of the monofilaments according to 15 Claims 7 to 9 for the manufacture of two-dimensional articles intended for filtration in the chemical, pharmaceutical and food industries.