ANTIMONY FREE FLAME-RETARDED EPOXY COMPOSITIONS

Abstract

A curable epoxy composition suitable for surface application, comprising one or more epoxy resin (s); 2, 4, 6-tribromophenyl end-capped tetrabromobisphenol A epoxy-based flame retardant; and phosphorus-containing compound selected from the group consisting of one or more of: ammonium polyphosphate; resorcinol bis (diphenyl phosphate); and liquid alkylated triphenyl phosphate ester. The composition is substantially Sb.sub.2O.sub.3-free.

Claims

1. A curable epoxy composition suitable for surface applications, comprising: A) one or more epoxy resin(s); B) 2,4,6-tribromophenyl end-capped tetrabromobisphenol A epoxy-based flame retardant of Formula (I): ##STR00010## wherein n indicates the degree of polymerization; and C) one or more phosphorus-containing compound(s) selected from the group of: C1) Ammonium polyphosphate; C2) Resorcinol bis (diphenyl phosphate); and C3) liquid alkylated triphenyl phosphate ester of the formula OP(OC.sub.6H.sub.5)m(OC.sub.6H.sub.4R.sub.1).sub.3-m, wherein m is 0, 1 or 2 and R.sub.1 is C.sub.3-C.sub.5 alkyl or a mixture thereof, wherein the composition is substantially Sb.sub.2O.sub.3-free.

2. A curable epoxy composition according to claim 1, comprising the ammonium polyphosphate and the resorcinol bis (diphenyl phosphate).

3. A curable epoxy composition according to claim 2, comprising: A) 100 weight parts of an epoxy resin; B) from 40 to 60 weight the parts of the 2,4,6-tribromophenyl end-capped tetrabromobisphenol A epoxy-based flame retardant of Formula I; and C) from 15 to 30 parts by weight of a mixture consisting of aluminum ammonium polyphosphate and resorcinol bis (diphenyl phosphate).

4. A curable epoxy composition according to claim 1, comprising the liquid alkylated triphenyl phosphate ester of the formula OP(OC.sub.6H.sub.5)m(OC.sub.6H.sub.4R.sub.1).sub.3-m, wherein m is 0, 1 or 2 and R.sub.1 is C.sub.3-C.sub.5 alkyl, or a mixture thereof.

5. A curable epoxy composition according to claim 4, wherein the liquid alkylated triphenyl phosphate ester is a mixed butylated triphenyl phosphate ester.

6. A curable epoxy composition according to claim 5, comprising: A) 100 weight parts of an epoxy resin; B) from 15 to 30 weight the parts of the 2,4,6-tribromophenyl end-capped tetrabromobisphenol A epoxy-based flame retardant of Formula I; and C) from 20 to 40 weight parts of the mixed butylated triphenyl phosphate ester.

7. A method of preparing a curable epoxy composition according to claim 4, comprising the steps of: dissolving the 2,4,6-tribromophenyl end-capped tetrabromobisphenol A epoxy-based flame retardant of Formula I in an alkylated triphenyl phosphate ester to obtain a resultant solution, such that the concentration of said flame retardant compound in the resultant solution is not less than 35% by weight; and combining said resultant.

8. A curable epoxy composition suitable for surface applications, comprising: A) one or more epoxy resin(s), B) at least one bromine-containing flame retardant selected from the group of brominated epoxy and end-capped derivatives thereof of the formula (II): ##STR00011## wherein n indicates degree of polymerization and R.sub.1 and R.sub.2 are independently selected from the group consisting of: ##STR00012## and C) liquid alkylated triphenyl phosphate ester of the formula OP(OC.sub.6H.sub.5)m(OC.sub.6H.sub.4R.sub.1).sub.3-m, wherein m is 0, 1 or 2 and R.sub.1 is C.sub.3-C.sub.5 alkyl or a mixture thereof.

9. A curable epoxy composition according to claim 8, wherein the liquid alkylated triphenyl phosphate ester is a mixed butylated triphenyl phosphate ester.

10. A curable epoxy composition according to claim 9, comprising: A) 100 weight parts of an epoxy resin; B) 45 to 55 weight parts of brominated epoxy of Formula II wherein R.sub.1 and R.sub.2 are both ##STR00013## said brominated epoxy having molecular weight of 700-3000; and C) from 20 to 30 weight parts of mixed butylated triphenyl phosphate ester.

11. A kit comprising first and second components, the first component being the curable composition of claim 1, and the second component comprising a curing agent for said curable composition, such that said first component is stored separately from said second component until use.

12. A process for applying a coating or a paint onto a surface, comprising curing the curable composition of claim 1 with the aid of a curing agent to form a fully cured flame retarded coating or paint onto said surface.

Description

EXAMPLES

[0049] Materials and Methods

[0050] Brominated Flame Retardants Polymers

[0051] TexFRon4002 (2,2-[(1-Methylethylidene)bis[(2,6-dibromo-4,1-phenylene)oxymethylene]]bisoxirane polymer with 2,2,6,6-tetrabromo-4,4-isopropylidenediphenol and 2,4,6-tribromophenol, CAS #135229-48-0); and F-2001 (CAS #68928-70-1, Tetrabromobisphenol A-tetrabromobisphenol A diglycidyl ether copolymer) were obtained from ICL-IP.

[0052] Phosphorus-Containing Compounds

[0053] Phosflex71B (butylated triphenyl phosphate ester, CAS Numbers: 56803-37-3 and 65652-41-7 and 78-33-1); Resorcinol-bis(diphenylphosphate) (Fyrolflex RDP, or High Purity RDP, Fyrolflex RDP-HP, CAS #125997-21-9); and TexFRonAG (Aluminum Ammonium polyPhosphate, CAS #1050443-25-8 were obtained from ICL-IP.

[0054] Epoxy Resins and Curing Agents

[0055] EPOKUKDO YD-127 (CAS 25068-38-6, Epoxy Resin derived from Bisphenol-A), EPOKUKDO YD-114EF (CAS 25068-38-6 & 9003-36-5 & 68609-97-2, Bisphenol-A/F type liquid Epoxy Resin diluted with aliphatic glycidyl ether, low viscosity) and DOMIDE GX-533 (CAS 68953-36-6 & 112-57-2 & 26142-30-3, Polyamidoamine/Epoxy adduct) were received from KUKDO Chemical Co., Ltd.

[0056] D.E.R. 331 Liquid Epoxy Resin (CAS 25085-99-8, a liquid reaction product of bisphenol A and epichlorohydrin) and DETA (CAS 111-40-0, Diethylenetriamine) were received from DOW Chemical Co., Ltd.

[0057] Auxiliary Additives

[0058] BYK-A500 (air release additive) was obtained from BYK-Chemie GmbH. CLiQSMART AF (defoamer) was obtained from Cliq Swiss Tech AG.

[0059] Flammability Tests:

[0060] Flammability UL 94 V is a method of evaluating both the burning and afterglow times after repeated flame application and dripping of the burning test specimen (see table). Each specimen was mounted with long axis vertical and supported such that its lower end is 10 mm above a Bunsen burner tube. A blue 20 mm high flame is applied to the center of the lower edge of the specimen for 10 seconds and removed. If the burning ceases within 30 seconds, the flame is reapplied for an additional 10 seconds. Five samples are needed for each formulation. If the time for even one sample (out of the five) is longer than 30 seconds then the test is noted as NR (=not rated).

TABLE-US-00001 Flammability rating UL 94 Time in seconds V-0 V-1 V-2 Burning time after flame application (10 s) 10 30 30 Total burning time (for 5 samples, two 50 250 250 applications) Burning and afterglow times of specimens 30 60 60 after second flame application (s) Dripping of burning specimens no no yes (ignition of cotton batting) Specimens completely burned no no no

Examples 1-6 (Reference/Comparative) and 7-9 (of the Invention)

Application of an Additive FR to Prepare Epoxy Flame-Retarded System

[0061] An epoxy resin was used as a casting compound to be flame retarded by the formulation of the present invention. The high viscosity epoxy resin (EPOKUKDO YD-127 or D.E.R. 331) was stirred by a Dissolver stirrer (R 1303 Dissolver stirrer IKA with EUROSTAR power control-visc motor, IKA) at 400 RPM speed. At 1500 RPM speed, defoamer (Byk-A500 or CLiQSMART AF) was added followed by the addition of at least one phosphorus source: Fyrolflex RDP, and/or TexFRonAG, and end-capped brominated epoxy FR (TexFRon4002). The speed was lowered to 500 RPM and stirring was continued for 20 minutes.

[0062] The curing agent (DOMIDE GX-533 or DETA) was introduced into the mixture and stirring was continued for 5 minutes.

[0063] The formulation was poured into a silicone mold to create models UL 3.2 mm thick, and was dried for 48 hours at room temperature (ambient curing). White opaque samples were formed. The flame retardancy UL-94V test was conducted after a week.

[0064] The different samples and results are shown in Table 1 below. The compositions are described in terms of percent by weight and weight in grams for each individual component. Reference Examples (compositions free of flame retardants) are indicated by the abbreviation Ref; Comparative Examples (compositions with flame retardants but not within the invention) are indicated by abbreviation Com.

TABLE-US-00002 TABLE 1 1 2 3 4 5 6 Example Ref Ref Com Com Com Com 7 8 9 Composition (% by weight) Epoxy resin 65% 41.2% 41.2% 41.2% 41.2% 41.5% 41.2% YD-127 25.9 g 25.9 g 25.9 g 25.9 g 25.9 g 25.9 g 20.6 g Epoxy resin 87.5% 56.1% D.E.R 331 61.6 g 50 g Curing agent 35% 22.2% 22.2% 22.2% 22.2% 22.3% 22.2 Domide GX-333 13.9 g 13.9 g 13.9 g 13.9 g 13.9 g 13.9 g 11.1 g% Curing agent 11.9% 7.5% DETA 8.4 g 6.7 g TexEron 4002 36% 20% 25% 24.7% 22.4 g 12.4 g 12.5 g 22 g TexFron AG 36% 20% 16% 7% 7% 22.4 g 12.4 g 10 g 3.5 g 6.2 g RDP 36% 16% 4% 3.9% 22.4 g 10 g 2 g 3.5 g % Br (calculated 20.16 0 0 0 11.2 14 13.8 % P (calculated) 0 7.2 3.8 5.7 3.2 1.8 1.8 Defoamer 0.4% 0.6% 0.4% 0.4% 0.4% 0.4% 0.4% 0.4% (Byk-A 500) 0.2 g 0.4 g 0.25 g 0.25 g 0.25 g 0.25 g 0.25 g 0.25 g Defoamer 0.8% (Cliqsmart AF) 0.7 g Properties (UL 94 flammability test: on 3.2 mm thick specimens) NR NR V-1 NR NR NR V-0 V-0 V-0

Examples 10-13 (Reference/Comparative) and 14-16 (of the Invention)

Application of Reactive FR to Prepare Epoxy Flame-Retarded System

[0065] An epoxy resin was used as a casting compound to be flame retarded by the formulation of the present invention. The epoxy resin (EPOKUKDO YD-114EF or D.E.R. 331) was stirred by a Dissolver stirrer (R 1303 Dissolver stirrer IKA with EUROSTAR power control-visc motor, IKA) at 400 RPM speed. At 1500 RPM speed, Defoamer (Byk-A500 or CLiQSMART AF) was added followed by the slow addition of the reactive brominated epoxy FR (F-2001) till full dissolution was observed. After clear solution was obtained, Phosflex71B was added while maintaining the stirring. The speed was lowered to 500 RPM and stirring was continued for 20 minutes.

[0066] The curing agent (DOMIDE GX-533 or DETA) was introduced into the mixture and stirring was continued for 5 minutes.

[0067] The formulation was poured into a silicone mold to create models UL 3.2 mm thick, and was dried for 48 hours at room temperature (ambient curing). Transparent samples were formed. The UL-94V test was conducted after a week.

[0068] The different samples and results are shown in Table 2 below. All samples were transparent. The compositions are described in terms of percent by weight and weight in grams for each individual component. Reference Examples (compositions free of flame retardant) are indicated by the abbreviation Ref; Comparative Examples (compositions with flame retardants but not within the invention) are indicated by abbreviation Com.

TABLE-US-00003 TABLE 2 10 11 12 Example Ref Ref Com 13 14 15 16 Composition (% by weight) Epoxy resin 65% 47.7% 45.7% 42.7% YD-114 EF 100 g 68 g 68 g 68 g Epoxy resin 87.5% 52.7% 50.4% D.E.R 331 61.6 g 68 g 68 g Curing agent 34.5% 29.4% 28.2 26.4% Domide GX-333 53 g 42 g 42 g 42 g Curing agent 11.9% 8.5% 8.1% DETA 8.4 g 11 g 11 g F-2001 22.4% 20.1% 24.8% 27.4% 32 g 32 g 32 g 37 g Phosflex 71B 25.6% 10.2% 12.8% 13.3% 38 g 16.3 g 16. 5 g 18 g % Br (calculated) 11.2 0 10.05 12.5 13.7 % P (calculated) 0 2.17 0.86 1.09 1.13 Defoamer 0.5% 0.6% 0.5% 0.5% 0.5% 0.6% (Byk-A 500) 0.7 g 0.4 g 0.7 g 0.7 g 0.7 g 0.8 g Defoamer 0.6% 0.7% (Cliqsmart .AF) 0.8 g 1 g Properties (UL 94 flammability test: on 3.2 mm thick specimens) NR NR NR NR V-2 V-2 V-0

Example 17

Dissolution Behavior of Brominated Flame Retardants in Phosphorus-Containing Liquids

[0069] Various (non-halogenated) phosphorus flame retardant liquids were tested for their ability to dissolve solid bromine-containing flame retardants. A vessel was charged with the liquid phosphorus compound, followed by slow addition of the solid bromine-containing flame retardant under stirring with the aid of R 1303 Dissolver stirrer IKA with EUROSTAR power control-visc motor, IKA; typically stirring rate was about 800 rpm. Solutions were then tested for stability against crystallization of the bromine-containing compound at low temperature, down to 25 C. (with seeding). The following phosphorus-containing liquids were tested as potential solvents for bromine-containing flame retardants:

[0070] Phosflex 71B; t-butylated triphenyl phosphate mixture of the formula (commercially available from ICL-IP):

##STR00007##

[0071] Fyrol 6; diethyl N,N bis (2-hydroxyethyl aminoethyl phosphonate of the formula (commercially available from ICL-IP):

##STR00008##

[0072] Fyrolflex RDP-HP; Resorcinol-bis(diphenylphosphate of the formula (commercially available from ICL-IP):

##STR00009##

[0073] VeriQuel R100; a phosphorus-rich reactive flame retardant, (commercially available from ICL-IP).

[0074] As to the solid bromine-containing flame retardants, in addition to F-2001 and Texfron 4002, a non-polymeric, phosphorus and bromine-based flame retarding agent was also investigated to determine its solubility in the solvents studied (Tris(tribromoneopentyl) phosphate, commercially available from ICL-IL as FR-370).

[0075] The maximal loading level achieved for a bromine-containing FR in the liquid phosphorus-based compound is tabulated below.

TABLE-US-00004 TABLE 3 Phosflex 71B Fyrol 6 Fyrolflex RDP-HP VeriQuel R100 FR-370 .sup.<9% <9% <9% <9% F-2001 37.5% <9% <9% <15% Texfron 4002 43.8% <15% <9% <9%

[0076] Phosflex 71B emerges as an excellent solvent for bromine-containing flame retardants of Formulas I and II, enabling the formation of fairly concentrated solutions of the bromine-containing epoxy FR's, especially for TexFron 4002.

Examples 18-19 (Reference) and 20 to 22 (of the Invention)

Application of an Additive FR to Prepare Transparent Epoxy Flame-Retarded Systems

[0077] First Step:

[0078] A solution of Phosflex 71B and TexFRon 4002 as described in the previous example was prepared. To a vessel which contains Phosflex 71B, TexFRon 4002 was slowly added during stirring (800 rpm, R 1303 Dissolver stirrer IKA with EUROSTAR power control-visc motor, IKA). The addition is continued reaching 43.8% loading level of TexFRon 4002 in the mixture. A viscous solution was obtained, which is stable against crystallization down to 25 C.

[0079] Second Step:

[0080] An epoxy resin (either EPOKUKDO YD-114EF or D.E.R. 331) was stirred by a Dissolver stirrer (R 1303 Dissolver stirrer IKA with EUROSTAR power control-visc motor, IKA) at 400 RPM speed. At 1500 RPM speed, Byk-A 500 was added followed by the slow addition of the Phosflex 71B/TexFRon4002 solution prepared in step 1 to obtain a clear homogeneous mixture. Then stirring speed was lowered to 500 RPM and stirring was continued for 20 minutes.

[0081] The curing agent (DOMIDE GX-533 or DETA) was then introduced into the mixture and stirring was continued for additional 5 minutes.

[0082] The formulation was poured into a silicone mold to create models UL 3.2 mm thick, and was dried for 48 hours at room temperature (ambient curing). Transparent samples were formed. The flame retardancy UL-94V test was conducted a week later.

[0083] The different samples and results are shown in Table 4 below. The compositions are described in terms of percent by weight and weight in grams for each individual component. Reference Examples (compositions free of flame retardant) are indicated by the abbreviation Ref.

TABLE-US-00005 TABLE 4 18 19 Example Ref Ref 20 21 22 Composition (% by weight) Epoxy resin 65% 48.5% YD-114 100 g 21.8 g Epoxy resin 87.5% 65.1% 58.5% D.E.R 331 61.6 g 26 g 17.5 g Curing agent 34.5% 26% Domide GX-333 53 g 11.74 g Curing agent 11.9% 9.4% 8% DETA 8.4 g 3.76 g 2.4 g Texfron 4002 11% 11% 14.5% 4.92 g 43.8 g 4.4 g Phosf1ex 71B 14% 14% 18.5% 6.3 g 5.6 g 5.6 g % Br (calculated) 6.2 6.2 8.10 % P (calculated) 1.19 1.19 1.57 Defoamer 0.5% 0.6% 0.4% 0.4% 0.4% (Byk-A 500) 0.7 g 0.4 g 0.18 g 0.16 g 0.12 g Properties (UL 94 flammability test on 3.2 mmthick specimens) NR NR V-2 V-2 V-0