Flame Retardant Polyolefin Articles

Abstract

A flame-retardant article including a polyolefin substrate having incorporated additives. The additives include: a specific phosphonate ester, a synergist including an N-alkoxy hindered amine, and a melamine cyanurate.

Flame retardant compositions, and use of the compositions for improving the flame retardancy of polyolefins, also are disclosed.

Claims

1. A flame-retardant article comprising a polyolefin substrate having additives incorporated therein, the additives comprising: a phosphonate ester of formula ##STR00056## wherein R.sub.1 and R.sub.2 are independently selected from a group consisting of alkyl, optionally substituted alkyl, benzyl, optionally substituted benzyl, phenyl, optionally substituted phenyl, naphthyl, and optionally substituted naphthyl, a synergist comprising an N-alkoxy hindered amine, and a melamine cyanurate.

2. The article of claim 1, wherein the polyolefin substrate comprises a polymer selected from a group consisting of polypropylene, polyethylene, and copolymers or mixtures thereof.

3. The article of claim 2, wherein the polyolefin has one or more additional polymers incorporated therein, the one or more additional polymers comprising polystyrene, polyamide, polyester, polycarbonate, epoxy resins, polyurethane, or copolymers or mixtures thereof.

4. The article of claim 1, wherein a physical dimension of the article is less than 1 mm.

5. The article of claim 4, wherein the article is a film having a thickness of less than 0.8 mm.

6. The article of claim 1, wherein both R.sub.1 and R.sub.2 are methyl.

7. The article of claim 1, wherein the N-alkoxy hindered amine is an NC.sub.1-C.sub.40alkoxy hindered amine unsubstituted or substituted by hydroxy, an N-cyclohexyloxy hindered amine, or a hindered amine comprising the structural element NOW, wherein W is a wax comprising between 50 and 1000 carbon atoms.

8. The article of claim 1, wherein the N-alkoxy hindered amine contains a structural element of formula ##STR00057## wherein G.sub.1 and G.sub.2 are independently from each other C.sub.1-C.sub.8alkyl or are together pentamethylene, Z, and Z.sub.2 are each methyl, or Z, and Z.sub.2 together form a linking moiety, and E is C.sub.1-C.sub.40alkoxy unsubstituted or substituted by hydroxy, or is cyclohexyloxy, or a residue of formula OW, wherein W is a wax comprising between 50 and 1000 carbon atoms.

9. The article of claim 1, wherein the N-alkoxy hindered amine is a compound of formula ##STR00058## wherein X is a group of formula ##STR00059## Y is (CH.sub.2).sub.6, each R is OC.sub.3H.sub.7 and n is an integer from 1 to 5, or a compound of formula ##STR00060## wherein R.sub.3 is n-propyl and X.sub.1 is n-butyl, or a compound of formula ##STR00061## wherein R.sub.4 is a group of formula ##STR00062## or a compound of formula ##STR00063##

10. The article of claim 1, wherein the N-alkoxy hindered amine is a compound of formula ##STR00064## wherein E.sub.1 is C.sub.1-C.sub.18alkoxy or hydroxyl-substituted C.sub.1-C.sub.18alkoxy, or a compound of the formula ##STR00065## wherein E.sub.2 and E.sub.3 are C.sub.1-C.sub.30alkoxy, or a compound of the formula ##STR00066## wherein E.sub.4 and E.sub.5 are C.sub.1-C.sub.30alkoxy or cyclohexyloxy, or a compound of the formula ##STR00067## wherein R.sub.5 is C.sub.1-C.sub.40alkyl, n is a number from 1 to 10, and W is a wax residue comprising between 50 and 1000 carbon atoms, or a compound of the formula ##STR00068## wherein n is a number from 1 to 50, and W is a wax residue.

11. The article of claim 1, wherein the N-alkoxy hindered amine contains a moiety of formula: ##STR00069##

12. The article of claim 1, wherein the N-alkoxy hindered amine is a compound of formula (7).

13. The article according to claim 1, wherein the phosphonate ester of formula (1) is present in an amount of from 0.02 to 20% by weight, based on the weight of the article, the hindered N-alkoxy amine is present in an amount of from 0.02 to 20% by weight, based on the weight of the article, and the melamine cyanurate is present in an amount of from 0.02 to 20% by weight, based on the weight of the article.

14. The article of claim 1, wherein a performance rating of the article from a UL-94 vertical burn (VB) test is V-0 when the article is in a form of a 125 mil injection molded bar.

15. A flame retardant composition comprising a phosphonate ester of formula ##STR00070## wherein R.sub.1 and R.sub.2 are independently selected from a group consisting of alkyl, optionally substituted alkyl, benzyl, optionally substituted benzyl, phenyl, optionally substituted phenyl, naphthyl, and optionally substituted naphthyl, an N-alkoxy hindered amine, and a melamine cyanurate.

16. The flame retardant composition according to claim 15, comprising in addition a polyolefin.

17. A method of increasing flame retardancy of polyolefins comprising the use of a composition comprising a phosphonate ester of formula ##STR00071## wherein R.sub.1 and R.sub.2 are independently selected from a group consisting of alkyl, optionally substituted alkyl, benzyl, optionally substituted benzyl, phenyl, optionally substituted phenyl, naphthyl, and optionally substituted naphthyl, an N-alkoxy hindered amine, and a melamine cyanurate.

18. A flame retardant composition comprising a phosphonate ester of formula ##STR00072## wherein R.sub.1 and R.sub.2 are independently selected from a group consisting of alkyl, optionally substituted alkyl, benzyl, optionally substituted benzyl, phenyl, optionally substituted phenyl, naphthyl, and optionally substituted naphthyl, and an N-alkoxy hindered amine of formula ##STR00073## wherein E.sub.1 is C.sub.1-C.sub.18alkoxy or hydroxyl-substituted C.sub.1-C.sub.18alkoxy.

19. The flame retardant composition according to claim 18, comprising in addition a polyolefin.

Description

EXAMPLE 1: FLAME RETARDANCY PERFORMANCE OF POLYETHYLENE FILMS CONTAINING DIFFERENT COMBINATIONS OF FLAME RETARDANTS

[0202] a) Polymer Component and Light Stabilizer

[0203] Polymer component (LLDPE): LLDPE, DOWLEX SC 2108G, manufacturer

[0204] Dow

[0205] Light stabilizer (LS): Chimassorb 2020, manufacturer BASF SE

[0206] b) Flame Retardant Components

[0207] FR-1: 1-(2-hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2,2,6,6-tetramethylpiperidine

[0208] FR-2: Pentaerythritol-di-methyl diphosphonate (available as AFLAMMIT PCO 900 from THOR GROUP LIMITED)

[0209] FR-3: Melamine cyanurate (available as Melapur MC from BASF SE)

[0210] c) LLDPE Film Manufacture

[0211] Unless stated otherwise, LLDPE, LS and the corresponding flame retardant components FR-1, FR-2 and FR-3 are dry blended in the amounts as indicated and then melt compounded into pellets on a co-rotating twin-screw extruder Berstorff 46D (lab size twin screw extruder, 25 mm screw diameter) at a maximum temperature T.sub.max of 230 C.

[0212] The pelletized fully formulated resin is then casted at a maximum temperature T.sub.max of 220 C. into 250 m films using a cast film equipment Collin CR-136/350 coupled with an extruder Collin E 30 M.

[0213] d) Performance of Formulation as Flame Retardant

[0214] The produced films are evaluated according to the standard DIN4102-Part 1 (May 1998). DIN4102-Part 1: The specimen is positioned vertically and the ignition flame is applied at the lower edge of the specimen (edge ignition test).

[0215] Classification is based on the time for flames to spread 150 mm of the specimen.

[0216] If the flame does not reach the 150 mm reference mark within 20 s, the tested film passes the test and is classified B2.

[0217] If the flame reaches the 150 mm reference mark within 20 s, the tested film is non classified (n.c.)

[0218] Concentrations of additives and performance of film specimen are given in Tables 1 and 2

TABLE-US-00001 TABLE 1 Concentrations of added additives in the LLDPE cast film Comparative Compositions (compositions not according to the present invention): Ref. 1, 2, 3, 4, 5 and 6 Compositions according to the present invention: Inv. 1 and Inv. 2 Film No. Additive* Ref. 1 No FR Ref. 2 2% FR-1 Ref. 3 5% FR-2 Ref. 4 5% FR-3 Ref. 5 0.4% FR-1 + 4.6% FR-3 Ref. 6 2.5% FR-2 + 2.5% FR-3 Inv. 1 0.4% FR-1 + 1.8% FR-2 + 2% FR-3 Inv. 2 0.4% FR-1 + 4.6% FR-2 *Stabilization of all films with 0.2% Chimassorb 2020

TABLE-US-00002 TABLE 2 Flaming test on 250 m LLDPE cast films according to modified DIN 4102-Part 1 (edge ignition) Ref. 1 Ref. 2 Ref. 3 Ref. 4 Ref. 5 Ref. 6 Inv. 1 Inv. 2 LLDPE 100% 98% 95% 95% 95% 95% 95.8% 95% FR-1 2% 0.4% 0.4% 0.4% FR-2 5% 2.5% 1.8% 4.6% FR-3 5% 4.6% 2.5% 2% DIN4102-B2 rating with fail fail pass fail fail fail pass pass 250 m films.sup.a) Burning time [sec].sup.b) 43 21 11 33 30 16 7 6 Damaged length [mm].sup.c) 160 99 70 190 190 93 53 46 Burning drips paper ignition.sup.d) yes yes no yes yes yes no no .sup.a)Rated pass if flaming does not reach the 150 mm gauge mark within 20 seconds after flame application according to the DIN 4102-Part 1 test norm. .sup.b)Burning time, in second, is the duration of the flaming after flame application up to the extinction of flame. .sup.c)Damaged lenght, in mm, is the vertical part of the film being burned after the extinction of flame. .sup.d)Rated no if molten and burning drips that have fallen on the filter paper does not ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm. no is the best rating.

[0219] Inv. 1 and Inv. 2 increase significantly the FR performance of the composition in comparison to Comparative Compositions Ref. 1, 2, 3, 4, 5 and 6. The burning time and also the damaged length are considerably lower for Inv. 1 and Inv. 2, both pass the test according to DIN 4102-Part 1, and no burning drips ignite a paper placed underneath the test specimen.

EXAMPLE 2: FLAME RETARDANCY PERFORMANCE OF POLYETHYLENE FILMS CONTAINING DIFFERENT COMBINATIONS OF FLAME RETARDANTS

[0220] a) Polymer Component and Light Stabilizer

[0221] Polymer component (LLDPE): LLDPE, DOWLEX SC 2108G, manufacturer Dow

[0222] Light stabilizer (LS): Chimassorb 2020, manufacturer BASF SE

[0223] b) Flame Retardant Components

[0224] FR-2: Pentaerythritol-di-methyl diphosphonate (available as AFLAMMIT PCO 900 from THOR GROUP LIMITED)

[0225] FR-3: Melamine cyanurate (available as Melapur MC from BASF SE)

[0226] FR-4: Compound of formula (5) (available as Flamestab NOR 116 FF from BASF SE)

[0227] FR-5: Compound of formula (3) (available as Tinuvin NOR 371 from BASF SE)

[0228] FR-6: Compound of formula (4)

[0229] c) LLDPE Film Manufacture

[0230] Unless stated otherwise, LLDPE, LS and flame retardant components FR-2, FR-3, FR-4, FR-5 and FR-6 are dry blended in the amounts as indicated and then melt compounded into pellets on a co-rotating twin-screw extruder Berstorff 46D (lab size twin screw extruder, 25 mm screw diameter) at a maximum temperature T.sub.max of 230 C.

[0231] The pelletized fully formulated resin is then casted at a maximum temperature T.sub.max of 220 C. into 250 m films using a cast film equipment Collin CR-136/350 coupled with an extruder Collin E 30 M.

[0232] d) Performance of Formulation as Flame Retardant

[0233] The produced films are evaluated according to the standard DIN4102-Part 1 (May 1998). DIN4102-Part 1: The specimen is positioned vertically and the ignition flame is applied at the lower edge of the specimen (edge ignition test).

[0234] Classification is based on the time for flames to spread 150 mm of the specimen.

[0235] If the flame does not reach the 150 mm reference mark within 20 s, the tested film passes the test and is classified B2.

[0236] If the flame reaches the 150 mm reference mark within 20 s, the tested film is non classified (n.c.)

[0237] Concentrations of additives and performance of film specimen are given in Tables 3 and 4

TABLE-US-00003 TABLE 3 Concentrations of added additives in the LLDPE cast film Comparative Composition (composition not according to the present invention): Ref. 1 Inventive Composition: Inv. 3, Inv. 4 and Inv. 5 Film No. Additive* Ref. 1 No FR Inv. 3 0.4% FR-4 + 2% FR-2 + 2% FR-3 Inv. 4 0.4% FR-5 + 2% FR-2 + 2% FR-3 Inv. 5 0.4% FR-6 + 2% FR-2 + 2% FR-3 *Stabilization of all films with 0.2% Chimassorb 2020

TABLE-US-00004 TABLE 4 Flaming test on 250 m LLDPE cast films according to modified DIN 4102-Part 1 (edge ignition) Ref. 1 Inv. 3 Inv. 4 Inv. 5 LLDPE 100% 95.6% 95.6% 95.6% FR-2 2% 2% 2% FR-3 2% 2% 2% FR-4 0.4% FR-5 0.4% FR-6 0.4% DIN4102-B2 rating with fail pass pass pass 250 m films.sup.a) Burning time [sec].sup.b) 43 16 8 6 Damaged length [mm].sup.c) 160 64 57 31 Burning drips paper yes no no no ignition.sup.d) .sup.a)Rated pass if flaming does not reach the 150 mm gauge mark within 20 seconds after flame application according to the DIN 4102-Part 1 test norm. .sup.b)Burning time, in second, is the duration of the flaming after flame application up to the extinction of flame. .sup.c)Damaged lenght, in mm, is the vertical part of the film being burned after the extinction of flame. .sup.d)Rated no if molten and burning drips that have fallen on the filter paper does not ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm. no is the best rating.

[0238] Compositions Inv. 3, 4 and 5, which are combinations of N-alkoxy hindered amines (FR-4 or FR-5 or FR-6) with pentaerythritol-di-methyl diphosphonate (FR-2) and melamine cyanurate (FR-3), pass DIN 4102-Part 1 test, and are effective in reducing burning time and damaged length.