Use of mono-substituted succinic anhydride

Abstract

The present invention refers to the use of at least one mono-substituted succinic anhydride before or during extrusion of a polymer composition comprising polylactic acid as polymer component and at least one calcium carbonate-comprising material as filler, to reduce the polymer decomposition during processing and/or to decrease the melt flow rate of such an extruded polymer as well as a method for reducing the polymer decomposition during processing and decreasing the melt flow rate of a polymer composition comprising polylactic acid as polymer component and at least one calcium carbonate-comprising material as filler, the use of a polymer composition obtainable by a process comprising the steps of a) providing at least one polylactic acid as polymer component, b) providing at least one calcium carbonate-comprising material as filler, c) providing at least one mono-substituted succinic anhydride and d) contacting the components of a), b) and c) in any order and e) extruding the contacted components of step d) as well as an article comprising a polymer composition obtainable by the aforementioned process.

Claims

1. A method for reducing the polymer decomposition during processing and/or decreasing the melt flow rate of a polymer composition comprising (a) a polymer component comprising at least one polylactic acid, (b) at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof, and (c) at least one calcium carbonate-comprising filler material, by at least 20%, measured according to DIN EN ISO 1133-1:2011 (procedure A, 2.16 kg, 210° C., granules), in comparison to the same polymer composition that has been treated the same way without the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof, the method comprising contacting the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof with the at least one calcium carbonate-comprising material before compounding, in that the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof are present on the surface of the at least one calcium carbonate-comprising material; wherein the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof are present in the polymer composition in an amount of at least 0.1 wt.-%, based on the total dry weight of the at least one calcium carbonate-comprising filler material, wherein the calcium carbonate comprising material is present in the polymer composition in an amount from 5 to 40 wt.-%, based on the total weight of the polymer component, wherein the calcium carbonate-comprising material has i) a weight median particle size d.sub.50 value in the range from 0.1 μm to 10 μm and/or ii) a top cut (d.sub.98) of 15 μm and/or iii) a specific surface area (BET) of from 0.5 to 150 m.sup.2/g as measured using nitrogen and the BET method according to ISO 9277:2010 and/or iv) a residual total moisture content of from 0.01 wt.-% to 1 wt.-%, based on the total dry weight of the at least one calcium carbonate-comprising material, wherein the ratio of the polylactic acid to optionally present further polymer components present in the polymer composition is from 99:1 to 20:80, based on the weight of the polymer components, and wherein the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof comprises at least one alkenyl mono-substituted succinic anhydride and/or salty reaction product(s) thereof.

2. The method of claim 1, wherein the at least one mono-substituted succinic anhydride consists of succinic anhydride mono-substituted with a group selected from a linear, branched, aliphatic and cyclic group having a total amount of carbon atoms from C2 to C30 and in case of branched groups C3 to C30 in the substituent.

3. The method of claim 1, wherein the at least one mono-substituted succinic anhydride is at least one alkenyl mono-substituted succinic anhydride.

4. The method of claim 1, wherein the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof are present in the polymer composition in an amount of from 0.2 to 1.5 wt.-%, based on the total dry weight of the at least one calcium carbonate-comprising filler material.

5. The method of claim 1, wherein the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof are present in the polymer composition in an amount of from 0.4 to 1.2 wt.-%, based on the total dry weight of the at least one calcium carbonate-comprising filler material.

6. The method of claim 1, wherein the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof are present in the polymer composition in an amount of from 0.1 to 1.2 wt.-%, based on the total dry weight of the at least one calcium carbonate-comprising filler material.

7. The method of claim 1, wherein the polymer component consists of at least one polylactic acid.

8. The method of claim 1, wherein the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof are present in the polymer composition in an amount of at least 0.005 wt.-%, based on the total weight of the polymer component.

9. The method of claim 1, wherein the calcium carbonate-comprising material is selected from the group consisting of ground calcium carbonate, precipitated calcium carbonate, and mixtures thereof.

10. The method of claim 1, wherein the calcium carbonate-comprising material has i) a weight median particle size d.sub.50 value in the range from 0.25 μm to 7 μm and/or ii) a top cut (d.sub.98) of 12.5 μm and/or iii) a specific surface area (BET) of from 1 to 60 m.sup.2/g as measured using nitrogen and the BET method according to ISO 9277:2010 and/or iv) a residual total moisture content of from 0.02 wt.-% to 0.5 wt.-%, based on the total dry weight of the at least one calcium carbonate-comprising material.

11. The method of claim 1, wherein the calcium carbonate-comprising material is present in the polymer composition in an amount from 0.1 to 85 wt.-%, based on the total weight of the polymer component.

12. The method of claim 1, wherein the polymer composition comprises further additives.

13. The method of claim 1, wherein the tensile strain at break of the polymer composition is increased by at least 40%, in comparison to the same polymer composition without the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof.

14. The method of claim 1, wherein the tensile strain at break of the polymer composition is increased by at least 100%, in comparison to the same polymer composition without the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof.

15. A method for reducing the polymer decomposition during processing and/or decreasing the melt flow rate of a polymer composition comprising (a) a polymer component comprising at least one polylactic acid, (b) at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof, and (c) at least one calcium carbonate-comprising material, by at least 20%, measured according to DIN EN ISO 1133-1:2011 (procedure A, 2.16 kg, 210° C., granules), in comparison to the same polymer composition that has been treated the same way without the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof, the method comprising a) providing a polymer component comprising at least one polylactic acid, b) providing at least one calcium carbonate-comprising filler material, c) providing at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof, d) contacting the components of a), b) and c), and e) compounding the contacted components of step d); wherein in contacting step d) firstly the at least one calcium carbonate-comprising material of step b) is contacted under mixing, in one or more steps, with the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof of step c) such that a treatment layer comprising the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof is formed on the surface of said at least one calcium carbonate-comprising material of step b) in an amount of at least 0.1 wt.-%, based on the total dry weight of the at least one calcium carbonate-comprising filler material, and secondly this surface-treated calcium carbonate-comprising filler material is contacted under mixing, in one or more steps, with the polymer component, wherein the calcium carbonate comprising material is present in the polymer composition in an amount from 5 to 40 wt.-%, based on the total weight of the polymer component, wherein the calcium carbonate-comprising material has i) a weight median particle size d.sub.50 value in the range from 0.1 μm to 10 μm and/or ii) a top cut (d.sub.98) of 15 μm and/or iii) a specific surface area (BET) of from 0.5 to 150 m.sup.2/g as measured using nitrogen and the BET method according to ISO 9277:2010 and/or iv) a residual total moisture content of from 0.01 wt.-% to 1 wt.-%, based on the total dry weight of the at least one calcium carbonate-comprising material, wherein the ratio of the polylactic acid to optionally present further polymer components present in the polymer composition is from 99:1 to 20:80, based on the weight of the polymer components, and wherein the at least one mono-substituted succinic anhydride and/or salty reaction product(s) thereof comprises at least one alkenyl mono-substituted succinic anhydride and/or salty reaction product(s) thereof.

16. A polymer composition obtainable by the method of claim 15.

17. The polymer composition of claim 16, wherein the polymer composition is suitable for use in hygiene products, medical products, healthcare products, filter products, geotextile products, agriculture products, horticulture products, clothing products, footwear products, baggage products, household products, industrial products, packaging products, or construction products.

18. An article comprising the polymer composition of claim 1.

19. The article of claim 18, wherein the article is selected from the group consisting of hygiene products, medical products, healthcare products, filter products, geotextile products, agriculture products, horticulture products, clothing products, footwear products, baggage products, household products, industrial products, packaging products, and construction products.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a graph of the values of the melt flow rate of CE1 and examples with 20 pph filler loading

(2) FIG. 2 shows a graph of the values of the melt flow rate of CE1 and examples with 10 pph filler loading

(3) FIG. 3 shows a graph of the values of the tensile strain at break of comparative examples CE1 to CE5 and inventive examples E1 to E5

EXAMPLES

(4) Measurement Methods

(5) The following measurement methods are used to evaluate the parameters given in the examples and claims.

(6) Particle Size Distribution (Mass % Particles with a Diameter<X) and Weight Median Diameter (d.sub.50) of a Particulate Material

(7) As used herein and as generally defined in the art, the “d.sub.50” value is determined based on measurements made by using a Sedigraph 5100 of Micromeritics Instrument Corporation and is defined as the size at which 50% (the median point) of the particle mass is accounted for by particles having a diameter equal to the specified value.

(8) The method and the instrument are known to the skilled person and are commonly used to determine grain size of fillers and pigments. The measurement is carried out in an aqueous solution of 0.1 wt.-% Na.sub.4P.sub.2O.sub.7. The samples are dispersed using a high speed stirrer and supersonics.

(9) BET Specific Surface Area of a Material

(10) Throughout the present document, the specific surface area (in m.sup.2/g) of the mineral filler is determined using the BET method (using nitrogen as adsorbing gas), which is well known to the skilled man (ISO 9277:1995). The total surface area (in m.sup.2) of the mineral filler is then obtained by multiplication of the specific surface area and the mass (in g) of the mineral filler prior to treatment.

(11) Amount of Surface-Treatment Layer

(12) The amount of the treatment layer on the calcium carbonate-comprising filler material is calculated theoretically from the values of the BET of the untreated calcium carbonate-comprising filler material and the amount of mono-substituted succinic anhydride that is used for the surface-treatment. It is assumed that 100% of the mono-substituted succinic anhydride added to the calcium carbonate-comprising filler material are present as surface treatment layer on the surface of the calcium carbonate-comprising filler material.

(13) Melt Flow Rate

(14) The “melt flow rate” is measured on a CEAST Melt Flow modular line instrument from Instron. The instruments and the measuring method are known to the skilled person. The melt flow rate is measured according to DIN EN ISO 1133-1:2011 by using procedure A. The polymer samples to be measured are in the form of granules or pellets with a length of 1 mm to 5 mm. An amount between 6 to 9 g is used for the measurements. Measurement of the samples is made at 210° C. with a nominal load of 2.16 kg using a capillary die having an inner diameter of 2.095 mm and a length of 8.00 mm. The preheating without load is performed for 300 seconds and the measure length is 20 mm.

(15) The melt flow rate is obtained under standard conditions. The term “standard conditions” according to the present invention refers to standard ambient temperature and pressure (SATP) which refers to a temperature of 298.15 K (25° C.) and an absolute pressure of exactly 100000 Pa (1 bar, 14.5 psi, 0.98692 atm). All measurements are performed on samples that have been stored under similar conditions after preparation.

(16) Tensile Strain at Break

(17) The “tensile strain at break” is measured on a Allround Z020 traction device from Zwick Roell. The instruments and the measuring method are known to the skilled person. The tensile strain at break is measured according to DIN EN ISO 527-2/1BA/50:2012, with a perforce of 0.1 MPa and a speed of 50 mm/min. The test specimen of the present invention have the geometry 1BA with the exception that the thickness of the samples is between 1.9±2 mm and the measuring length is 25×5 mm.

(18) The tensile strain at break is obtained under standard conditions. All measurements are performed on samples that have been stored under similar conditions after preparation.

(19) Materials

(20) Calcium Carbonate-Comprising Filler Materials

(21) Calcium Carbonate-Comprising Filler Material 1 (Powder 1)

(22) Powder 1 is a dry ground calcium carbonate from Italy (d.sub.50=2.6 μm, d.sub.98=15 μm, BET specific surface area=2.6 m.sup.2/g).

(23) Calcium Carbonate-Comprising Filler Material 2 (Powder 2)

(24) Powder 2 is a stearic acid-treated dry ground calcium carbonate from Italy (d.sub.50=2.6 μm, d.sub.98=15 μm, BET specific surface area=2.6 m.sup.2/g).

(25) Calcium Carbonate-Comprising Filler Material 3 (Powder 3)

(26) 1.00 kg of a dry ground calcium carbonate from Italy (d.sub.50=2.6 μm, d.sub.98=15 μm, BET specific surface area=2.6 m.sup.2/g) is placed in a mixer (Somakon MP-LB Mixer, Somakon Verfahrenstechnik, Germany), and conditioned by stirring for 10 minutes (2000 rpm, 120° C.). After that time, 0.8 parts by weight relative to 100 parts by weight CaCO.sub.3 of ASA 1 is added to the mixture. Stirring and heating is then continued for another 20 minutes (120° C., 2000 rpm). After that time, the mixture is allowed to cool and the free-flowing powder is collected (powder 3).

(27) Calcium Carbonate-Comprising Filler Material 4 (Powder 4)

(28) 1.00 kg of a dry ground calcium carbonate from Italy (d.sub.50=2.6 μm, d.sub.98=15 μm, BET specific surface area=2.6 m.sup.2/g) is placed in a mixer (Somakon MP-LB Mixer, Somakon Verfahrenstechnik, Germany), and conditioned by stirring for 10 minutes (2000 rpm, 120° C.). After that time, 0.4 parts by weight relative to 100 parts by weight CaCO.sub.3 of ASA 1 is added to the mixture. Stirring and heating was then continued for another 20 minutes (120° C., 2000 rpm). After that time, the mixture is allowed to cool and the free-flowing powder is collected (powder 4).

(29) Calcium Carbonate-Comprising Filler Material 5 (Powder 5)

(30) 1.00 kg of a dry ground calcium carbonate from Italy (d.sub.50=2.6 μm, d.sub.98=15 μm, BET specific surface area=2.6 m.sup.2/g) is placed in a mixer (Somakon MP-LB Mixer, Somakon Verfahrenstechnik, Germany), and conditioned by stirring for 10 minutes (2000 rpm, 120° C.). After that time, 1.2 parts by weight relative to 100 parts by weight CaCO.sub.3 of ASA 1 is added to the mixture. Stirring and heating is then continued for another 20 minutes (120° C., 2000 rpm). After that time, the mixture is allowed to cool and the free-flowing powder is collected (powder 5).

(31) Polymer Component

(32) Polylactic acid that is used as polymer component is commercially available from NatureWorks under the trade name Biopolymer 2003D. The polylactic acid is a PDLLA comprising 4.6 wt.-% of D isomers, based on the total weight of the polylactic acid. Furthermore, the PDLLA has a specific gravity of 1.24 and a glass transition temperature from 55 to 60° C. The PDLLA has residual monomer content of 0.21 wt.-%, based on the total weight of the polylactic acid.

(33) Mono-Substituted Succinic Anhydride

(34) ASA 1

(35) Mono-substituted alkenyl succinic anhydride (2,5-Furandione, dihydro-, mono-C.sub.15-20-alkenyl derivs., CAS No. 68784-12-3) is a blend of mainly branched octadecenyl succinic anhydrides (CAS #28777-98-2) and mainly branched hexadecenyl succinic anhydrides (CAS #32072-96-1). More than 80% of the blend is branched octadecenyl succinic anhydrides. The purity of the blend is >95 wt %. The residual olefin content is below 3 wt %.

(36) Polymer Compounding Preparations

(37) The compounded polymer compositions are prepared in a two-step synthesis.

(38) In a first step, the polymer component polylactic acid is added to a twin roll mill (Collin 150, Walzwerk 150×400, Germany) followed by the addition of the calcium carbonate-comprising filler material after the PLA has melted. The mono-substituted succinic anhydride can be present on the surface of the calcium carbonate-comprising filler material and/or can be added separately afterwards. The compounding of the composition is done with a total amount of 120 g of material (filler+polymer+ASA) using the conditions given in table 1 below.

(39) TABLE-US-00001 TABLE 1 Compounding conditions Calcium carbonate comprising filler material Polylactic acid as Various amounts filler component Various amounts Composition additive optional Roll speed 20 rpm Speed difference −40% (typical) Thickness: 0.6 mm Temperature 200° C.

(40) After obtaining a homogeneous mixture, the melt is removed from the rolls and added again (operation repeated 3 times) for a total compounding time on the roll mill of 11 minutes (unless indicated otherwise).

(41) In a second step, the compounded polymer composition is treated in a press (Collin P 300 P, Dr. Collin, Germany). Approx. 90 g of the compounded polymer composition are cut in pieces and pressed between 2 metal plates to obtain sheets of the following dimensions: 169×169×2 mm.sup.3. The used press program is given in table 2 below.

(42) TABLE-US-00002 TABLE 2 Press conditions Temperature [° C.] Time [s] Pressure [bar] 210 60 20 210 90 200 cooling 90 200

(43) The compounding is performed in a room at 26±2° C. at 40-50% rH.

(44) The amounts of the used materials and the formulation of the compounded polymer compositions is given in table 3 below.

(45) TABLE-US-00003 TABLE 3 Compounded polymer compositions Polymer Calcium carbonate ASA in component comprising filler weight Example in weight parts material in weight parts parts CE1 100 — — CE2 100 Powder 1 (20) — CE3 100 Powder 2 (20) — CE4 100 Powder 1 (10) — CE5 100 Powder 2 (10) — E1 100 Powder 3 (20) * E2 100 Powder 1 (20) ASA 1 (0.16) E3 100 Powder 3 (10) * E4 100 Powder 4 (20) * E5 100 Powder 5 (20) * * The ASA is present on the surface of the calcium carbonate-comprising material

(46) Melt Flow Rate Analysis of the Compounded Polymer Compositions

(47) The melt flow rate of comparative examples CE1 to CE5 and inventive example E1 to E5 is given in table 4 below. Furthermore, the melt flow rate of the neat polylactic acid as received from the supplier, which has not been subjected to the compounding conditions as described above is given as CE6.

(48) TABLE-US-00004 TABLE 4 melt flow rate MFR % reduction vs Example (g/10 min) comparative example CE6 8.6 / CE1 15.8 / CE2 40.4 / CE3 82.5 / CE4 31.2 / CE5 42.1 / E1 22.4 44.6% (CE2) E2 28.8 28.7% (CE2) E3 25.0 19.9% (CE4) E4 28.2 30.2% (CE2) E5 16.0 60.4% (CE2)

(49) As can be seen from the examples by the use of at least one mono-substituted succinic anhydride before or during compounding of a polymer composition comprising polylactic acid as polymer component and at least one calcium carbonate-comprising material as filler, it is possible to decrease the melt flow rate of such a compounded polymer composition. More precisely, it is possible to decrease the melt flow rate between 19.9% to 60.4% in comparison to the same polymer composition that has been treated the same way without at least one mono-substituted succinic anhydride. The measured results also are graphically visualized in FIGS. 1 and 2.

(50) Tensile Strain at Break Analysis of the Compounded Polymer Compositions

(51) The tensile strain at break of comparative examples CE1 to CE5 and inventive example E1 to E5 is given in table 5 below. All given results are average values of at least 5 tests.

(52) TABLE-US-00005 TABLE 5 Tensile strain at break Tensile strain % increase vs Example at break (%) comparative example CE1 3.1 — CE2 2.8 — CE3 2.6 — CE4 3.0 — CE5 2.6 — E1 13.3 375% (CE2) E2 6.1 118% (CE2) E3 7.2 140% (CE4) E4 7.0 150% (CE2) E5 12.4 343% (CE2)

(53) As can be seen from the examples by the use of at least one mono-substituted succinic anhydride before or during compounding of a polymer composition comprising polylactic acid as polymer component and at least one calcium carbonate-comprising material as filler, it is possible to increase the tensile strain at break of such a compounded polymer composition. More precisely, it is possible to increase the tensile strain at break between 118% to 375% in comparison to the same polymer composition that has been treated the same way without at least one mono-substituted succinic anhydride. The measured results also are graphically visualized in FIG. 3.