Silyl functional compound for improving flame retardant properties

Abstract

The invention relates to the use of a silyl functional compound b), which silyl functional compound comprises a N—O—Si bond, for improving the flame retardant properties of a composition comprising an organic polymer a), which is one of a thermoplastic polymer or a thermoset polymer or a mixture thereof.

Claims

1. A process of preparing a flame retardant composition, the process comprising: mixing an organic polymer component and an amount of a silyl functional component sufficient to impart a flame retardant property to the flame retardant composition, the organic polymer component including one or more of a thermoplastic polymer and a thermoset polymer, and the silyl functional component including a compound comprising a N—O—Si bond.

2. The process according to claim 1, further comprising mixing one or more crosslinking components with the organic polymer component and the silyl functional component.

3. The process according to claim 1, wherein the amount of the silyl functional component is in a range of 0.1 to 15.0% by weight based on the total weight of the organic polymer component and the silyl functional component.

4. The process according to claim 1, wherein the compound comprises a functional group comprising the N—O—Si bond, wherein the functional group has the formula (I) ##STR00003## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 independently represent an organic group or a hydrogen atom.

5. The process according to claim 4, wherein R.sup.1 is a hydrogen atom and R.sup.2 is an organic group.

6. The process according to claim 4, wherein R.sup.1—N—R.sup.2 together form a cyclic group.

7. The process according to claim 6, wherein the cyclic group is selected from a heterocyclic amine group, and a cyclic imide group.

8. The process according to claim 4, wherein the compound comprises a plurality of functional groups having the formula (I).

9. The process according to claim 1, wherein the compound has a decomposition temperature of at least 140° C.

10. The process according to claim 1, further comprising mixing at least one other flame retardant with the organic polymer component and the silyl functional component, the at least one other flame retardant being different from compound.

11. The process according to claim 10, wherein the at least one other flame retardant includes any one or more of an inorganic flame retardant, a brominated flame retardant, a phosphorus based flame retardant, a magnesium flame retardant and a nitrogen based flame retardant.

12. The process according to claim 11, wherein the at least one other flame retardant includes one or more of aluminum trihydroxide, magnesium dihydroxide, and antimony trioxide.

13. A process of preparing a flame retardant composition, the process comprising: providing an organic polymer component including one or more of a thermoplastic polymer and a thermoset polymer, providing a silyl functional component including a compound comprising a N—O—Si bond, and mixing the organic polymer component and the silyl functional component.

14. The process according to claim 1, wherein the amount of the silyl functional component is in a range of 0.1 to 10.0% by weight, based on the total weight of the organic polymer component and the silyl functional component.

15. The process according to claim 6, wherein the cyclic group has one or more substituents.

16. The process according to claim 6, wherein the cyclic group comprises a carbazole group or phthalimide.

Description

EXAMPLES

(1) Preparation of Silylamines:

(2) TABLE-US-00001 TABLE 1 Educt Description N-Hydroxyphthalimide Supplier: Sigma Aldrich, CAS Nr. 524-38-9 Chloro(methyl) Supplier: Sigma Aldrich, CAS Nr. 144-79-6 diphenylsilane Triethylamine Supplier: Sigma Aldrich, CAS Nr. 121-44-8 Tetrahydrofuran Supplier: Sigma Aldrich, CAS Nr. 109-99-9 Hexane Supplier: Sigma Aldrich, CAS Nr. 110-54-3 Uvinul 5050H Supplier: BASF, CAS Nr. 152261-33-1 Hydrogen peroxide Supplier: Sigma Aldrich, CAS Nr. 7722-84-1 Ascorbic acid Supplier: Sigma Aldrich, CAS Nr. 50-81-7 1-hydroxy-1H-pyrrole- Supplier: Fisher scientific, CAS Nr. 6066-82-6 2,5-dione

(3) General Procedure to Prepare Silylamines:

(4) Synthesis of Silylamines A and C:

(5) Silylamines A and C were prepared using the formulation in table 2.

(6) Xg Educt 1, Xg THF and Xg triethylamine were placed in a 2.0 liter three-necked round bottom flask equipped with mechanical stirrer and drop funnel as well as nitrogen inlet and condenser.

(7) The mixture was cooled down to 5-6° C. Then Xg Educt 2 were added drop wise under nitrogen atmosphere with stirring within 15 min. After the addition was completed Xg of THF were added. The temperature was kept for further 10 min. before it was allowed to raise to 23° C. The stirring was continued under nitrogen atmosphere for further 2 h.

(8) The solvent was removed from the filter cake by distillation using the rotary evaporator at 45° C. and 16.0 mbar. The mixture was washed with XmL of hexane and filtered under nitrogen atmosphere.

(9) Synthesis of Silylamine B:

(10) Xg Educt 1, Xml THF and Xg Hydrogen peroxide were placed in a 2.0 liter three-necked round bottom flask equipped with mechanical stirrer and drop funnel as well as nitrogen inlet and condenser. The stirring was continued under nitrogen atmosphere for further 24 h. A solution of Xg ascorbic acid in Xml THF was added within 1 hour interval. The mixture was heated up to 60° C. The mixture was cooled down to 5° C. Then Xg Educt 2 were added dropwise under nitrogen atmosphere with stirring within 15 min. After the addition was completed Xml of THF were added. The temperature was kept for further 10 min. before it was allowed to raise to 23° C. The stirring was continued under nitrogen atmosphere for further 4 h.

(11) The solvent was removed by distillation using the rotary evaporator. The mixture was washed with Xml of hexane and filtered under nitrogen atmosphere.

(12) TABLE-US-00002 TABLE 2 Amount Amount Silyla of Educt of Educt mine 1 [g] Educt 1 2 [g] Educt 2 Comment A  10.10 N-Hydroxy- 14.71 Ph.sub.2MeSiCl Triethylamine: phthalimide 6.26 g THF: 100 g + 23 g Hexane: 400 ml B 183.9  Uvinul 5050H 14.30 Ph.sub.2MeSiCl Triethylamine: 6.20 g THF: 100 g + 80 g Hexane: 450 ml Hydrogen peroxide: 1 g Ascorbic acid: 10.71 C  7.05 1-hydroxy- 14.52 Ph.sub.2MeSiCl Triethylamine: 6.5 g 1H-pyrrole- THF: 100 g + 80 g Hexane: 400 ml 2,5-dione

(13) TABLE-US-00003 TABLE 3 Decomposition temperature Silylamine Decomposition temperature A 247° C. B 241° C. C 218° C.

(14) Performance Testing of Silylamines as Flame Retardant Synergists

(15) The following examples show exemplarily the use of the Silylamines as flame retardant synergists in different plastics formulations. The performance of the products is compared to products, which are state of the art.

(16) TABLE-US-00004 TABLE 4 Raw Material Description Moplen HF 501N Supplier: Lyondell Basell, CAS Nr. 9003-07-0 Homo polypropylen MFR 10 g/10 min (230° C./ 2.16 kg nach ISO 1133-1), PCO 900 Supplier: Thor, A Flammit PCO 900, organic phosphorus compound containing 24% phosphorus, flame retardant

(17) To show the effectivity of the Silylamines as flame retardant synergists in plastics formulations the components A-C were used in state of the art formulations and the flame retardancy performance was tested.

(18) General Method of Preparation for Testing Silylamines in Polyethylene-Based Formulations:

(19) Thermoplast:

(20) Preparation according to the formulation in table 6 and 7.

(21) Thermoplastic polymer powder was mixed with an additional flame retardant synergist. This mixture was fed to a dosing balance of an extruder (model Coperion ZSK 18 K38). The silylamine was fed to a side inlet of the extruder via a second dosing balance. Extrusion was carried out using the temperature profile detailed further below and at 300 rpm. The overall capacity of the extruder was 2 kg/h. The composition left the extruder via a slot die (dimensions 28 mm×3 mm) and was cooled. The extruded strings were granulated to particles having a size in the range of approximately 0.1 to 0.5 mm.

(22) Temperature profiles in the extruder from polymer entry funnel to slot die:

(23) For polypropylene: 180° C./190° C./195° C./200° C./195° C./190° C./185° C.

(24) Preparation of Test Specimens

(25) Test specimen of dimension 125 mm×13 mm×3.2 mm and 125×13 mm ×1.6 mm were prepared by injection molding, and subsequently stored at a relative humidity of 45 to 55% and a temperature of 20 to 25° C. for 24 hours.

(26) General Procedure to Test Flame Retardancy Properties in Plastics Formulations:

(27) Test procedure of flame retardant properties

(28) The flame retardant properties of test specimen were determined in a UL-94 fire chamber based on DIN EN 60695-11-10. The test specimen were secured in the sample holders of the UL-94 fire chamber. The burner upper surface was positioned 1 cm below the lower surface of the test specimen, the flame was positioned in a 45° angle and a heating output of 50 W. The test specimen were exposed to the flame for 10 seconds, before removing the flame. If the test specimen extinguished by itself within 10 seconds, the process was repeated until the sample burned or until 5 cycles were performed. For evaluation, the criteria summarized in the table below were used. Test specimen which exhibited fire retardant properties below rating V 2 according to DIN EN 60695-11-10 were marked as F. This rating was added to better distinguish the properties. It is not part of DIN EN 60695-11-10.

(29) TABLE-US-00005 TABLE 5 Rating of fire retardant properties Criteria F V0 V1 V2 Time to extinction of flame of single >30 s  10 s  30 s  30 s test specimen Accumulated time to extinction of >250 s 50 s 250 s 250 s flame of 5 test specimen Time to extinction of flame plus >60 s  30 s  60 s  60 s smoldering time of single test specimen after the second flame cycle Falling droplets or particles yes no no yes Ignition of the cotton underlay by yes no no yes burning particles

(30) The results are summarized in the tables below. The amounts are given in parts by weight (pbw). Comparative Examples are marked with an *.

(31) TABLE-US-00006 TABLE 5 Amount of Further Amount of further flame flame Amount of UL 94 Example Silylamine Silylamine retardant retardant Polymer Polymer classification thickness 1* — — — — 100 Polypropylen F 3.2 mm (Moplen HF 501N) 2* — — 10 PCO 900 100 Polypropylen F 3.2 mm (Moplen HF 501N) 3* — — 10 PCO 900 100 Polypropylen F 1.6 mm (Moplen HF 501N) 4  2 A 10 PCO 900 100 Polypropylen V0 1.6 mm (Moplen HF 501N) 5  2 B 10 PCO 900 100 Polypropylen V0 3.2 mm (Moplen HF 501N) 6  2 C 10 PCO 900 100 Polypropylen V0 1.6 mm (Moplen HF 501N)

(32) It can be concluded that the addition of silyl-functional compounds comprising a N—O—Si bond significantly improves the flame retardant properties of the polymer compositions according to the invention.