Biologically Degradable Polymer Fibre Made of Renewable Raw Materials

Abstract

The invention relates to a biologically degradable polymer fibre made of renewable raw materials with good physical properties, as well as a method for its production and its use.

Claims

1. Bi-component polymer fibre, wherein the fibre comprises a component A (core) and a component B (shell) and (i) the melting point of the thermoplastic polymer in component A is higher by at least 5° C. than the melting point of the thermoplastic polymer in component B; and (ii) the fibre material comprising component A comprises a biopolymer A and the fibre material comprising component B comprises a biopolymer B; (iii) the biopolymer A is an aliphatic polyester, preferably a biopolymer comprising repeat units of the lactic acid and biopolymer B is an alipathic polyester, wherein the biopolymer B and the biopolymer A differ regarding their chemical structure; characterised in that the bi-component polymer fibres have a hot-air thermal shrink rate in the range from 0% to 10% measured at 110° C.

2. Polymer fibres according to claim 1, characterised in that the biopolymer A and biopolymer B are respectively biologically degradable, synthetic biopolymers according to ASTM D5338-15.

3. Polymer fibres according to claim 1 or claim 2, characterised in that the biopolymer A comprises repeat units of the lactic acid, of the hydroxy butyric acid and/or of the glycol acid, preferably of the lactic acid and/or glycol acid, in particular of the lactic acid.

4. Polymer fibre according to claim 1, 2 or 3, characterised in that the biopolymer A is a polylactide acid with number average of molecular weight (Mn) of min. 500 g/mol, preferably min. 1,000 g/mol, more preferably min. 5,000 g/mol, most preferably min. 10,000 g/mol, in particular min. 25,000 g/mol.

5. Polymer fibres according to one or more of the claims 1 to 4, characterised in that the biopolymer A is a polylactide acid with number average of molecular weight (Mn) of max. 1,000,000 g/mol, preferably max. 500,000 g/mol, in particular max. 100,000 g/mol.

6. Polymer fibres according to claim 1, 2 or 3, characterised in that the biopolymer A is a polylactide acid with numerical mean of molecular weight (Mw) in the range from 750 g/mol to 5,000,000 g/mol, preferably in the range from 5,000 g/mol to 1,000,000 g/mol, more preferably in the range from 10,000 g/mol to 500,000 g/mol, most preferably in the range from 30,000 g/mol to 500,000 g/mol, with the polydispersity of these polymers being in the range between 1.5 and 5.

7. Polymer fibres according to one or more of the claims 1 to 6, characterised in that the biopolymer A is a polylactide acid with an inherent viscosity, measured in chloroform at 25° C., of 0.1% polymer concentration in the range from 0.5 dl/g and

8. 0 dl/g, preferably in the range from 0.8 dl/g and 7.0 dl/g, more preferably in the range from 1.5 dl/g and 3.2 dl/g.

8. Polymer fibres according to one or more of the claims 1 to 7, characterised in that the biopolymer A gas a glass transition temperature higher than 20° C., preferably higher than 25° C., in particular higher than 30° C., more preferably higher than 35° C., in particular higher than 40° C.

9. Polymer fibres according to one or more of the claims 1 to 8, characterised in that the biopolymer B has a number average molecular weight (Mn) of at least 10,000 daltons, in particular at least 12,000 daltons, more preferably at least 12,500 daltons and at most up to 120,000 daltons, in particular up to 100,000 daltons, most preferably up to 80,000 daltons.

10. Polymer fibres according to one or more of the claims 1 to 8, characterised in that the biopolymer B has a mean molecular weight (Mn) of at least 50,000 daltons and at most up to 240,000 daltons, in particular up to 190,000 daltons, most preferably up to 100,000 daltons.

11. Polymer fibres according to one or more of the claims 1 to 10, characterised in that the biopolymer B has a melt flow index of 5 to 200 grams per 10 minutes, in particular 15 to 160 grams per 10 minutes, more preferably 20 to 120 grams per 10 minutes, measured according to the ASTM test method D1238-13.

12. Polymer fibres according to one or more of the claims 1 to 11, characterised in that the biopolymer B has a glass transition temperature of at least 5° C., more preferably at least 10° C., most preferably at least 15° C. below the glass transition temperature of the biopolymer A.

13. Polymer fibres according to one or more of the claims 1 to 12, characterised in that the biopolymer B is an aliphatic polyester, with repeat units of at least 5 carbon atoms, preferred biopolymers B are polyhydroxyvalerate, polyhydroxybutyrate-hydroxyvalerate copolymer and polycaprolactone and succinate-based aliphatic polymers, in particular polybutylene succinate, polybutylene succinate adipate and polyethylene succinate, as well as polyethylene oxalate, polyethylene malonate, polyethylene succinate, polypropylene oxalate, polypropylene malonate, polypropylene succinate, polybutylene oxalate, polybutylene malonate, polybutylene succinate and mixtures of the same and co-polymers of these compounds.

14. Polymer fibres according to claim 13, characterised in that the biopolymer B is a polybutylene succinate and/or a polybutylene succinate co-polymer.

15. Polymer fibres according to one or more of claims 1 to 14, characterised in that they are stretched after spinning in the form of a tow, the temperature during the stretching of the tow is between 30° C. and 80° C., and therefore above the glass transformation temperature of the biopolymers A and B, and the stretching takes place in exposure to steam with the stretching rate preferably being between 1.2 and 6.0.

16. Polymer fibres according to claim 15 characterised in that the spun tow has a yarn count of 240 to 360 ktex before stretching.

17. Polymer fibres according to claim 15 of 16, characterised in that the biopolymer B has a number average molecular weight (Mn) of at least 10,000 daltons, in particular at least 12,000 daltons, more preferably at least 12,500 daltons and at most up to 30,000 daltons, in particular up to 28,000 daltons, most preferably up to 25,000 daltons.

18. Polymer fibres according to claim 17, characterised in that biopolymer B has a melting viscosity determined at a temperature of 190° C. in the range from 250 to 400 Pa*s at 200s.sup.−1 (shear) and 125 to 190 Pa*s at 1200s.sup.−1 (shear), preferably in the range from 260 to 380 Pa*s at 200s.sup.−1 (shear) and 130 to 180 Pa*s at 1200s.sup.−1 (shear), more preferably in the range from 275 to 375 Pa*s at 200s.sup.−1 (shear) and from 135 to 175 Pa*s at 1200s.sup.−1 (shear).

19. Textile web in particular received from a wet-laid procedure, comprising polymer fibres as defined by claims 1 to 18.

20. Use of the polymer fibres as defined by claims 1 to 18 for the production of aqueous suspensions.

Description

EXAMPLE

[0138] The raw materials PLA 6202D of NatureWorks and BioPBS Fz71PM were spun into a corresponding fibre by means of bicomponent spinning technology. The PLA concentration as core material was 70 wt.-%, the shell percentage was 30 wt.-%. The set transport of overall 331 g/min with a nozzle with 827 holes and a haul-off speed of 1000 m/min resulted in a spun yarn count of 4.0 dtex. In addition, an antioxidant with 0.05% active substance concentration was added to the PBS to reach a corresponding good spinning behaviour at the spinning temperature of 240° C. As usual, finish was applied on the spinning material to permit further processing.

[0139] Then, the spun product was processed at an unstretched tow length of approx. 42 ktex on a conventional staple fibre line.

[0140] Stretched in steam medium of 2.2 dtex and fixated at 90° C. in the circulating air oven, the following textile technology key values of the crimped variant resulted for the further processing in the airlay procedure:

[0141] Linear density: 2.3 dtex

[0142] Hardness: 28 cN/tec

[0143] Stretching: 41%

[0144] Shrinkage (110° C.): 1.5%

[0145] Crimping: 5 Bg/cm

[0146] BioPBS Fz71PM is a polybutylene succinate with a melting viscosity of (190° C.) 279 Pa*s at 200s.sup.−1 (shear) and 139 Pa*s at 1200s.sup.−1 (shear).

[0147] PLA 6202D is a polylactide acid with a relative density of 1.24 g/cm.sup.3 (according to ASTM D792) and a melt flow index (g/10min@210° C.) in the range of 15-30. The glass transition temperature is 55-60° C. (according to ASTM D3417) and the crystalline melt temperature is 160-170° C. (according to ASTM D3418).