POLYMER COMPOSITION

Abstract

A polymer composition [composition (M)], said composition (M) comprising i) at least one polyglycolic acid polymer [polymer (PGA)] and ii) at least one amorphous polyester [polymer (APES)], said polymer (APES) being present in the composition (M) in an amount of at least 0.10 and of at most 45 wt %, with respect to the combined weight of polymer (PGA) and polymer (APES). Method of making such composition and method of producing a multilayer stretched product from such composition.

Claims

1-15. (canceled)

16. A polymer composition [composition (M)], said composition (M) comprising i) at least one polyglycolic acid polymer [polymer (PGA)] and ii) at least one amorphous polyester [polymer (APES)], said polymer (APES) being present in the composition (M) in an amount of at least 0.10 wt % and of at most 45 wt %, with respect to the combined weight of polymer (PGA) and polymer (APES).

17. The composition (M) according to claim 16, wherein polymer (PGA) is a branched polyglycolic acid polymer [polymer (b-PGA)].

18. The composition (M) according to claim 17, wherein polymer (b-PGA) comprises units derived from polycondensation of: (i) glycolic acid (GA); (ii) optionally, at least one hydroxyl acid having only one hydroxyl group and only one carboxylic acid group different from GA [hydroxyacid (A)], wherein the molar amount of hydroxyacid (A) is at most 5% moles, with respect to the sum of moles of GA and hydroxyacid (A); (iii) at least one polyol comprising at least three hydroxyl groups and being free from carboxylic acid group [polyol (H)], wherein the amount of polyol (H) is such that the number of hydroxyl groups thereof is at least 0.050% and at most 0.750%, with respect to the overall number of hydroxyl groups of glycolic acid and of the hydroxyacid (A), if present; and (iv) optionally, at least one polyacid comprising at least two carboxylic acid groups and being free from hydroxyl groups [polyacid (O)], wherein the amount of polyacid (O) is such that the number of carboxyl groups thereof is at least 0.050% and at most 0.750%, with respect to the overall number of hydroxyl groups of glycolic acid and of the hydroxyacid (A), if present.

19. The composition (M) according to claim 16, wherein the polymer (APES) is selected from amorphous terephthalate-based copolyester [polymer (ATBPE)], amorphous polyethylene isophthalate [polymer (APEI)], amorphous polyethylene naphthalate [polymer (APEN)], amorphous polyethylene furanoate [polymer (APEF)] and amorphous polytrimethylene furandicarboxylate [polymer (APTF)].

20. The composition (M) according to claim 19, wherein the polymer (APES) is polymer (ATBPE).

21. The composition (M) according to claim 20, wherein polymer (ATBPE) is selected from amorphous polyethylene terephthalate [polymer (APET)], amorphous polycyclohexylenedimethylene terephthalate [polymer (APCT)], amorphous polybutylene terephthlate [polymer (APBT)] and amorphous polytrimethylene terephthalate [polymer (APTT)].

22. The composition (M) according to claim 16, wherein polymer (APES) is present in composition (M) in an amount of at least 0.50 wt % and of at most 25 wt %, with respect to the combined weight of polymer (PGA) and polymer (APES).

23. The composition (M) according to claim 16, wherein polymer (APES) is present in composition (M) in an amount of at least 1 wt % and of at most 20 wt %, with respect to the combined weight of polymer (PGA) and polymer (APES).

24. A method of making composition (M) according to claim 16, said method including mixing polymer (PGA) and polymer (APES), and optionally additional ingredients.

25. The method according to claim 24, said method including a step of mixing in the molten state polymer (PGA) and polymer (APES), and optionally additional ingredients.

26. A method of producing a multilayer stretched product, said method comprising: (i) forming a multilayer resin laminate including at least one layer of composition (M) according to claim 16, and at least one layer of a thermoplast different from polyglycolic acid polymers, by processing from the melt; (ii) stretching the multilayer resin laminate, so as to produce the multilayer stretched product.

27. The method according to claim 26, wherein the thermoplast is selected from the group consisting of polyester resins, polystyrene resins, acrylic acid or methacrylic acid resins, nylon resins, sulfide resins, and polycarbonate resins.

28. The method according to claim 26, wherein the step of forming the said multilayer resin laminate is performed by co-extrusion molding or co-injection molding.

29. The method according to claim 26, wherein the multilayer resin laminate is cooled and solidified after step (i) before undergoing step (ii).

30. The method according to claim 26, wherein the multilayer resin laminate is submitted to step (ii) without any intermediary cooling and re-heating step.

Description

EXAMPLES

[0151] The invention will be now be described in more detail with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the invention.

Raw Materials

[0152] b-PGA is a branched PGA manufactured according to the teachings of WO 2018/115008 (SOLVAY S.A.), obtained from a mixture of GA, trimethylol propane (0.14 mole for 100 moles of GA), isophthalic acid (0.21 mole for 100 moles of GA) in the presence of methanesulfonic acid (1.350 g/kg of GA). b-PGA is characterized by a melting temperature (T.sub.m) and a glass transition temperature (T.sub.g), both measured by DSC according to ISO 11357-3 (European Standard) or ASTM D3418 (US Standard), during first heating from 20° C. to 270° C. at 10° C./minute under nitrogen on 10 mg of sample, of 236° C. for T.sub.m and 45° C. for T.sub.g. b-PGA is also characterized by a melt viscosity of 527 Pa×sec measured according to ASTM D4440-08 at a shear rate of 10 sec.sup.−1 (at an oscillation rate of 10 rad/sec), at a temperature of 260° C. and with the use of parallel plate.

[0153] ATBPE is an amorphous terephthlate-based copolyester commercially available under trade name EASTOBOND™ Copolyester 19411 from Eastman which is characterized by a T.sub.g of 51° C. (measured according to ASTM D3418 during first heating from 20° C. to 270° C. at 10° C./minute under nitrogen on 10 mg of sample) and an inherent viscosity (measured according to ASTM D4603) of 0.74.

[0154] CPET is a crystalline polyethylene terephthlate commercially available under trade name EASTAPAK™ Polymer 9921 from Eastman which is characterized by a T.sub.g of 79° C., a T.sub.m of 236° C., a heat of fusion of 59 kJ/kg (all three being measured according to ASTM D3418 during first heating from 20° C. to 270° C. at 10° C./minute under nitrogen on 10 mg of sample), and an inherent viscosity (measured according to ASTM D4603), of 0.80.

[0155] PET is polyethylene terephthlate commercially available under trade name Ramapet R180 from Indorama venture.

General Description of Compounding Procedure

[0156] Compositions as described in the examples below were compounded using a twin screw extruder Clextral BC21 (21 mm diameter, length 43 D, 9 barrel zones, vacuum in zone 7, 2 weight feeders and one hopper under nitrogen flow, die with 2 rond holes, water bath and air dryer, pelletizer) operating with the temperature profile as defined in Table 1, and recovering the mixture thereof under the form of pellets.

TABLE-US-00001 TABLE 1 Zone Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10 Z11 T (° C.) 100 260 260 260 250 250 220 220 220 230 230

Determination of the Peak Temperature of Crystallization (T.SUB.C.) and of the Heat of Fusion (ΔH)

[0157] Peak temperature of crystallization (T.sub.c) and heat of fusion (ΔH) were measured by DSC at 10° K/min, according to ISO 11357-3 (European Standard) or ASTM D3418 (US Standard), during first heating from 20° C. to 270° C. at 10° C./minute under nitrogen on 10 mg of sample.

Determination of Hydrolysis Resistance

[0158] 10 grams of pellets of each of the compositions as described in the examples below were put in 250 ml of demineralized water in a clogged glass bottle. After an ageing in oven at 38° C., measurement of the conductivity of water was performed each 24 hours and the amount of time required to have an increase of the conductivity of water (due to the release of glycolic acid) was taken as the hydrolysis resistance.

Production of Films from Composition (M)

[0159] Films were prepared from the compositions as described in the examples below.

[0160] For this, a five-layer film A/B/C/B/A (A=PET, B=PET and C=composition comprising b-PGA as described in each example) was produced by coextrusion using three extruders connected to each other by a feed block (265° C.) and a flat die 300 mm wide (265° C.). A finishing calender was used to quench the film at 50° C., adjust the thickness and rewind the film.

[0161] The first extruder was a Brabender extruder (diameter 30 mm, length 25 D, 3 heating zones) and was fed with PET previously dried with dried air (dew point −3° C.) at 170° C. for 8 hours.

[0162] The second and third extruders were Brabender extruders (diameter 19 mm, length 25 D, 3 heating zones). The second was fed with PET previously dried as explained above and the third one was fed with each of the compositions described in the examples previously dried (dew point −3° C.) at 130° C. for 16 hours.

[0163] The temperatures in each zone and the screw speed for each of the 3 extruders are detailed in Table 2.

TABLE-US-00002 TABLE 2 Temperature Temperature Temperature Screw Extruders in Z1 (° C.) in Z2 (° C.) in Z3 (° C.) speed (rpm) First 250 260 265 40 Second 270 260 255 42 Third 240 250 260 38

[0164] The thickness of the films was 18+/−3 μm for layers A/B, 10+/−3 μm for layer C and 18+/−3 μm for layers B/A.

Measurement of Oxygen Permeation (Initial Intrinsic Value and Barrier Stability)

[0165] The measurement of oxygen permeation was made according to ASTM D3985.

[0166] The principle of the method consists in determining the amount of oxygen which passes through a film, prepared as explained above, of each of the compositions described in the examples below, per unit time and unit area, for a defined temperature and relative humidity.

[0167] For this, the film was placed in a cell so that it separates this cell into two. The first part was supplied with oxygen and the second flushed with nitrogen. The oxygen which passed through the film was transported by the nitrogen to the coulometric detector. The latter thus determined the amount of oxygen per unit time. Knowing the surface area of the cell, the amount of oxygen in cm.sup.3 per day and per m.sup.2 was determined and afterwards expressed for 10 μm of b-PGA layer (initial intrinsic value of oxygen permeation).

[0168] The machine used was an Oxtran 2/21 and 2/22 (Mocon) machine, conditioned at 38° C. and 90% relative humidity.

[0169] The films were placed in aluminium bags and stored at 23° C. and 50% relative humidity before being placed in the various measurement cells of the machine.

[0170] The barrier stability was the time necessary to reach 2 times the initial intrinsic value of oxygen permeation.

Delamination Resistance

[0171] The measurement of delamination resistance was made according to T-peel Test ASTM D1876 on the films (size of samples: 25×200 mm) prepared as described above. One end of the film samples was submitted to an immersion in a caustic soda solution at 65° C. to separate layers B from layer C, allowing to clamp the 2 parts of the film in tensile jaws.

[0172] The average adhesion strength (N/cm) was then measured according to tensile testing with Hounsfield tensile machine (tensile sensor 5 N-23° C.-254 mm/min).

Example 1 (According to the Invention)

[0173] A composition comprising 90 wt % of b-PGA and 10 wt % of ATBPE was prepared according to compounding procedure detailed above.

Comparative Example 2

[0174] A composition comprising 90 wt % of b-PGA and 10 wt % of CPET was prepared according to compounding procedure detailed above.

Comparative Example 3

[0175] A composition comprising 100 wt % of b-PGA was prepared according to compounding procedure detailed above.

[0176] The peak temperature of crystallization (TO and the heat of fusion (AH), measured for the different examples according to the method described above, are mentioned in Table 3 below.

[0177] The hydrolysis resistance measured for the different examples according to the method described above, is mentioned in Table 4 below.

[0178] The oxygen permeation (initial intrinsic value and barrier stability) measured for the different examples according to the method described above, is mentioned in Table 5 below.

[0179] The delamination resistance measured for the different examples according to the method described above, is mentioned in Table 6 below.

TABLE-US-00003 TABLE 3 Examples T.sub.C (° C.) ΔH (J/g) Example 1 156 61 Comparative Example 2 163 67 Comparative Example 3 166 74

TABLE-US-00004 TABLE 4 Resistance to Examples hydrolysis (hours) Example 1 170 Comparative Example 2 160 Comparative Example 3 150

TABLE-US-00005 TABLE 5 Initial intrinsic value of oxygen permeation (cm.sup.3/m.sup.2 day) Barrier for 10 μm of stability Examples b-PGA layer (hours) Example 1  9 290 Comparative Example 2 10 285 Comparative Example 3 11 150

TABLE-US-00006 TABLE 6 Average adhesion Examples strength (N/cm) Example 1 3.0 Comparative Example 2 2.7 Comparative Example 3 2.8

[0180] The above-mentioned results illustrate that the composition according to the invention is characterized by a lower T.sub.C, a lower ΔH, a better resistance to hydrolysis and leads to film presenting a higher average adhesion strength, compared to the compositions according to the comparative examples.

[0181] Surprisingly, the film obtained with the composition according to the invention is characterized by a very good oxygen permeation and an extended barrier stability.