WO2012127463A1

WO2012127463A1 - Flame retardant composition and flame retarded high impact polypropylene

Info

Publication number: WO2012127463A1
Application number: PCT/IL2012/000124
Authority: WO
Inventors: Sergei V. Levchik; Edward D. Weil; Gerald R. Alessio; Yaniv Hirschsohn; Yoav Bar-Yaakov; Pierre Georlette
Original assignee: Bromine Compounds Ltd.
Priority date: 2011-03-20
Filing date: 2012-03-20
Publication date: 2012-09-27

Abstract

The invention provides a flame retardant additive composition comprising: at least one high molecular weight brominated epoxy polymer or its end-capped derivative, at least one low molecular weight brominated epoxy polymer or its end-capped derivative, and at least one compatibilizer, said compatibilizer either having polyethylenic structure or is organotitanate. There is also provided a flame retardant masterbatch which is produced by heat extrusion of the flame retardant additive composition and producing pellets which are dust free and easy to handle for further compounding. Further provided is a flame retarded high impact polypropylene composition comprising high impact polypropylene, the flame retardant additive composition of the present invention and an inorganic synergist.

Description

FLAME RETARDANT COMPOSITION AND FLAME RETARDED HIGH IMPACT

POLYPROPYLENE

FIELD OF THE INVENTION

The present invention relates to a flame retardant additive composition and more particularly to a bromine-based flame retardant composition for high impact polypropylene.

BACKGROUND OF THE INVENTION

Flame retarded polypropylene finds applications in various fields such as electrical (wire nuts, lamp sockets, coil bobbins, connectors and wire and cables), housing of electrical appliances, TV yokes, pipes for water discharge, fibers for textile applications, films and sheets for roofing. In most of these applications, flame retardancy is provided by flame retardant systems based on a combination of brominated flame retardants with antimony trioxide as a synergist.

The present invention relates to a flame retarded high impact polypropylene resin, obtained by using the class of bromine-containing flame retardants obtainable by reacting tetrabromobisphenol A with epichlorohydrin. The reaction of tetrabromobisphenol A with epichlorohydrin is known to yield various reactive brominated epoxy polymers having high bromine content, which may be used as such, or in the form of their end- capped non-reactive derivatives, as flame retardants in plastic materials.

Brominated epoxy polymers were mentioned in the art for polyolefin applications. For example WO 99/07787 discloses a composition comprising polyolefin based resin and a brominated epoxy polymer. WO 01/0751 1 discloses the use of bromine epoxy polymers with an average molecular weight of 1,000-50,000 in polyolefins in combination with a second brominated flame retarding agent which is a monomeric or dimeric flame retardant containing aliphatic bromine. US 5,705,544 discloses fire- retarded polypropylene and ethylene-propylene copolymers which contain brominated epoxy polymer having an average molecular weight of at least 3,000 g/mol. JP 11- 021392 indicates that polypropylene is combined with brominated flame retardants such as brominated epoxy compounds. JP 08-302102 discloses a flame retarded polypropylene which comprises halogenated bisphenol A epoxy resin having molecular weight of 700- 5000 in combination with tetrabromobisphenol A-S-2,3 dibromophenol. JP 07-173345 describes a polypropylene resin which is rendered flame-retarded by the use of brominated bisphenol A type epoxy resin.

The brominated epoxy resins useful as flame retardants are sometimes applied in the form of masterbatch compositions, as disclosed in JP 03-227370 and JP 08-109269. Mixtures of brominated epoxy polymers having different molecular weights, for reducing the fiammability of high density polyethylene and high impact polystyrene are described in WO 2011/077439 and WO 2011/1 17865, respectively, where these mixtures are also provided in the form of highly concentrated masterbatch compositions.

SUMMARY OF THE INVENTION

It has now been found that the combination of high molecular weight brominated epoxy polymer of molecular weight of 5,000 and higher, together with low molecular weight brominated epoxy polymer having molecular weight of less than 5,000, and preferably less than 2,500 or the end-capped derivatives of said epoxy, when added together with a small quantity of an inorganic synergist such as antimony trioxide, to high impact polypropylene resin will provide a satisfactory level of flame retardancy to the resin, such that the resulting resin exhibits reduced burning times compared to high impact polypropylene resin which contains only high molecular weight epoxy resin. The high impact polypropylene compositions of the invention do not exhibit surface migration of the flame retardant component after being aged at 70°C for one month and then visually observed for surface migration of the flame retardants. Another advantage offered by the combination of the high molecular weight brominated epoxy polymer with the low-molecular weight brominated epoxy polymer relates to the possibility of producing a concentrate of the flame retardants (a masterbatch composition), allowing the flame retardants to be conveniently incorporated into the high impact polypropylene resin, as discussed in more detail below. This invention further relates to the flame retardant composition comprising at least one high molecular weight brominated epoxy polymer, at least one low molecular weight brominated epoxy polymer and a compatibilizer having a polyethylenic structure, and the use of this composition in high impact polypropylene resin which allows to preserve high impact strength of the resin.

In particular, it has been unexpectedly discovered that the combination of high molecular weight brominated flame retardant epoxy polymer and low molecular weight brominated epoxy polymer and a compatibilizer having a polyethylenic structure, or organotitanate compatibilizer, provides sufficient flame retardant efficiency and good physical properties, more specifically high impact strength in high impact polypropylene resin such as Izod or falling weight impact resistance.

Accordingly, the present invention is directed to a flame retardant additive composition comprising:

(a) at least one high molecular weight brominated epoxy polymer or its end- capped derivative, having average molecular weight above 5,000;

(b) at least one low molecular weight brominated epoxy polymer or its end- capped derivative, having average molecular weight less than 2,500; and

(c) at least one compatibilizer, said compatibilizer either having a polyethylenic structure or is organotitanate.

Further, the present invention provides the flame retardant additive composition set forth above in a masterbatch form, which is produced by heat extrusion of the components of said flame retardant additive composition to form pellets which are dust free and easy to handle for further compounding.

Still further, the present invention is also directed to a flame retarded high impact polypropylene composition comprising the flame retardant additive composition of the present invention and an inorganic synergist.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to flame retardant additive compositions that contain a unique combination of a high molecular weight brominated epoxy polymer, a low molecular weight brominated epoxy polymer and a compatibilizer having a polyethylenic structure. Such flame retardant additive compositions can be used in high impact polypropylene resin while maintaining suitable impact properties.

The high molecular weight brominated epoxy polymers suitable for use according to the invention are brominated epoxy polymers represented by Formula I

(I)

wherein n, the average degree of polymerization, is in the range between 24 and 115, and more preferably between 80 and 115, and R¹ and R² are glycidyl ether groups

0

/ \

H ₂C— CH— C H₂— -

Preferred high molecular weight brominated epoxy polymers have an average molecular weight between 10000 and 80000. Examples of commercially available high molecular weight brominated epoxy polymers which are suitable for use include F-2100, F-2300H and F-2400 from ICL-IP. Especially preferred is brominated epoxy polymer of Formula (I) having average molecular weight between 40000 and 60000, e.g., F-2400.

Preferably, the high molecular weight brominated polymer is present in an amount from about 10 wt. % to about 50 wt. % of the total weight of the flame retardant composition and more preferably from about 10 wt. % to about 30 wt. % of the total weight of the flame retardant composition.

The low molecular weight brominated epoxy polymers suitable for use according to the invention are selected from the group consisting of brominated epoxy polymers and end-capped derivatives thereof, wherein said brominated epoxy polymers and their end-capped derivatives are represented by formula (I) wherein n, the number average degree of polymerization, is in the range between 0.5 and 7.2, and more preferably between 1 and 6, and R¹ and R¹ are independently selected from the group consisting of glycidyl ether groups O

H₂C— CH-CH₂

-hydroxypropyltribromophenol ether groups

(the polymers terminated with the latter group are the end-capped derivatives).

Preferred low molecular weight brominated epoxy and end-capped derivatives thereof have molecular weight between 700 and 2,500, e.g. 1000-2100. An example of commercially available low molecular weight brominated epoxy polymer terminated with glycidyl ether groups is F-2016 manufactured by ICL-IP having an average molecular weight of 1600. Examples of commercially available low molecular weight brominated epoxy polymers terminated with tribromophenol which are suitable for use in this invention include F-3014, F-3020 and F-3516 from ICL-IP. In the following table, some useful low molecular weight brominated polymers terminated with tribromophenol (namely, the end-capped polymers) are defined by the characteristic distribution of the individual tribromophenol-terminated compounds, as may be determined by gel permeation chromatography (GPC), and also by their average molecular weight:

Preferably, the low molecular weight brominated polymer is present in an amount from about 30 wt. % to about 80% wt. % of the total weight of the flame retardant composition and more preferably from about 40% wt. % to about 70% wt. % of the total weight of the flame retardant composition.

The flame retardants of Formula (I), which are suitable for reducing the flammability of polypropylene compositions according to the invention, can be prepared by methods known in the art (for example, US 4,605,708, EP 467364, EP 1587865 and WO 2007/132463).

In one embodiment of this invention high impact polypropylene is a copolymer of propylene and ethylene. Copolymerization of propylene and ethylene decreases crystallinity of the resin and increases amorphous areas which results in higher impact properties. There are commercially available random copolymers and block copolymers of ethylene and propylene.

In another embodiment of this invention, high impact polypropylene is an intimate blend of polypropylene and polyethylene, where polyethylene amorphous phases are dispersed in polypropylene continuous phase. This type of blends can be prepared by extrusion or by joint polymerization of ethylene and propylene in one reactor using for example MgCh catalyst technology.

In even another embodiment of this invention, high impact polypropylene is a random copolymer of polypropylene and a-olefin such as for example 1-octene or 1- decene. These copolymers have low density and show high impact properties at low temperature. The high impact polypropylene can be terpolymer of propylene, ethylene and a-olefm.

Because of the presence of polyethylene or a-olefin structures in the high impact polypropylene resin it is typically more combustible than polypropylene homopolymer and therefore requires a higher level of a flame retardant to achieve UL-94 flammability ratings.

It has now been unexpectedly found that a certain class of compatibilizers, which have polyethylenic structure, improve compatibility of the mixture of brominated epoxy polymers and high impact polypropylene, whereas other classes of compatibilizers, shown in comparative examples, which have polypropylenic structure do not improve compatibility. As used herein, the term "compatibilizers having polyethylenic structure" and the like refer to compatibilizers which contain polyethylene component or segment(s), whereas compatibilizers having polypropylenic structure contain polypropylene component or segment(s). For example, a compatibilizer which is suitable for use in the invention is a copolymer of ethylene and a second, polar monomer such as maleic anhydride. In one embodiment of this invention the compatibilizers are those selected from the group consisting of silanes, titanates, aluminates, zirconates, and mixtures thereof, particularly the organosi lanes, organotitanates, organoaluminates and/or organozirconates.

In one specific embodiment of this invention the compatibilizer is selected from the group of organotitanates bearing long linear aliphatic chains of C₈ - C22. Preferred are phosphatotitanante, e.g., tris(dialkylphosphato)titanate, wherein the alkyl is preferably octyl. An example of a suitable phosphatotitanate is neopentyl(diallyl)oxy, tri(dioctyl phosphate) titanate available under trade name Ken-React CAPS L 12/L from Kenrich Petrochemicals.

In another embodiment of this invention the compatibilizers are selected from polymers of polar and nonpolar structures which are produced by customary polymerization reactions.

In one specific embodiment of this invention compatibilizers for use with the current invention include maleic anhydride functionaiized high-density polyethylene (HDPE), maleic anhydride functionaiized low-density polyethylene (LDPE) or maleic anhydride functionaiized linear low density polyethylene (LLDPE). The maleic anhydride functionaiized polyethylene can be produced by reactive extrusion of the PE in the presence of both a radical initiator and maleic anhydride in a twin-screw extruder which results in maleic anhydride grafted polyethylene. The maleic anhydride functionaiized polyethylene can be also produced by random terpolymerization in autoclave of ethylene, maleic anhydride and another polar monomer, for example acrylic ester.

In another specific embodiment the compatibilizer is selected from the group of copolymers of ethylene and another comonomer bearing an epoxy group. An example of such compatibilizers is random copolymer of ethylene and glycidyl methacrylate polymerized under high pressure in an autoclave.

Preferably, the compatibilizer is present in an amount from about 2 wt. % to about 20% wt. % of the total weight of the flame retardant composition and more preferably from about 5% wt. % to about 15% wt. % of the total weight of the flame retardant composition. The flame retardant composition of the present invention can further contain an inorganic synergist, selected from the group consisting of inorganic antimony, inorganic bismuth, inorganic tin, inorganic iron or inorganic zinc compounds. The most preferable are inorganic antimony compounds, e.g. antimony trioxide, antimony pentoxide, sodium antimonite and the like.

Preferably, the inorganic synergist is present in an amount from about 5 wt. % to about 40% wt. % of the total weight of the flame retardant composition and more preferably from about 10% wt. % to about 25% wt. % of the total weight of the flame retardant composition.

This invention is further directed to the flame retarded high impact polypropylene composition comprising the flame retardant composition of the invention. Generally speaking the amount of bromine and the amount of inorganic synergist are responsible for providing sufficient level of flame retardancy to the high impact polypropylene composition.

Preferably, the bromine content in the high impact polypropylene composition is from about 4 wt. % to about 10 wt. % of the total weight of the high impact polypropylene composition which ensures V-2 rating according to UL-94 vertical test.

Preferably the inorganic synergist content is from about 0.5 wt. % to about 3 wt. % of the total weight of the high impact polypropylene composition.

The high impact polypropylene composition of the present invention can also include other additives such as antioxidants, stabilizers, fillers anti-dripping agent such as fluorinated homo- or copolymers such as polytetrafluoroehtylene or processing aid agents, pigments etc., as well as other flame retardants.

As explained above, the brominated epoxy polymer flame retardant(s) are added to the formulation at a concentration sufficient for adjusting the bromine content within the range indicated above. It is not mandatory that this bromine content be supplied in its entirety by the brominated epoxy polymers mentioned above, and one or more additional brominated flame retardants may be added to the formulation. However, preferably, the mixture of brominated flame retardants incorporated into the polyethylene according to the invention consists of brominated epoxy polymers, said mixture being free of brominated compounds such as decabromodiphenyl oxide or decabromodiphenyl ethane. The high impact polypropylene compositions of the invention may be prepared as follows. The various ingredients of the composition are blended together according to their respective amounts. Generally, the ingredients are first dry blended using suitable mixing machines, or may be dosed separately into the extruder. The powder mixture may then be processed and compounded to form homogeneous polypropylene pellets, for example, by using a twin-screw extruder. The polypropylene pellets obtained are dried, and are suitable for feed to an article shaping process such as injection or extrusion molding. Process parameters are described in more detail in the examples that follow.

As an alternative to the separate addition of the brominated epoxy polymer flame retardants and compatibilizer to the extruder, the masterbatch route can be employed. For example, the brominated epoxy polymers as defined by Formula (Ϊ) and optionally also the compatibilizer having a polyethylenic structure may be incorporated into the polymeric formulation via a masterbatch form (which may optionally contain the inorganic synergist, preferably antimony trioxide). A masterbatch is a concentrate composition comprising a suitable carrier, and a relatively high proportion of the flame retardant(s). Typically, the carrier is a polymer which is intended to facilitate the mixing of the master batch and improve the compatibility of the masterbatch and the biend polymer (the blend polymer is the polymer combined with the master batch; in the present case, the blend polymer is polypropylene). Another advantage resulting from using the masterbatch is that it is made of dust free pellets, and is hence environmentally friendly. Suitable carrier polymers applied in the master batch are therefore similar or identical to the blend polymer. However, it was found that it is possible to prepare a masterbatch containing the low molecular weight brominated epoxy polymer of Formula (I) or end-capped brominated epoxy polymer of Formula (I) in combination with a carrier material comprising high molecular weight brominated epoxy polymer. As an example of a suitable carrier material, a brominated epoxy polymer with a molecular weight of 40,000-60,000 g/mol may be used, such as F-2400, which is commercially available from 1CL-IP. Thus, the high molecular weight brominated epoxy polymer functions in the masterbatch both as a carrier material and as an active flame retarding agent.

Thus, in one embodiment, the masterbatch of the invention comprises a combination of brominated epoxy polymers, a compatibilizer having a polyethylenic structure and optionally antimony trioxide. The concentration of the low molecular weight brominated epoxy polymer of Formula (I) or tribromophenol end-capped brominated epoxy polymer of Formula (I) is from about 30 wt. % to about 80% wt. % of the total weight of the masterbatch and more preferably from about 40% wt. % to about 70% wt. %. The concentration of the high molecular weight brominated epoxy polymer of Formula (I) is from about 10 wt. % to about 50 wt. % of the total weight of the masterbatch and more preferably from about 10 wt. % to about 30 wt. %. The concentration the compatililizer having polyethylenic structure is from about 10 wt. % to about 50 wt. % of the total weight of the masterbatch and more preferably from about 10 wt. % to about 30 wt. %, e.g. from 10 wt. % to about 20 wt. %. If antimony trioxide is also incorporated in the masterbatch, then its concentration may be between 0.1 and 30 wt. %. Other additives may also be included in the masterbatch, including inert carriers such as polypropylene or polyethylene at concentration in the range of 3 to 30 wt. %. The bromine content of the masterbatch is preferably not less than 40 wt. %.

The masterbatch composition of the invention is prepared by melting the brominated epoxy flame retarding agents and the compatibilizer in an extruder, e.g., in a twin-screw extruder. The starting materials are employed either as powders or granules. The extruded strands produced are cooled, e.g., with water. A subsequent drying step is employed, followed by strand pelletizing to provide the masterbatch composition in a granular form. A preferred masterbatch composition of the invention comprises high molecular weight brominated epoxy of Formula I with molecular weight from 40000 to 60000 (e.g., F-2400), low molecular weight brominated epoxy of Formula I or its end- capped derivative with molecular weight from 1000 to 2100 (e.g., F-2016 or F-3020) and compatibilizer having polyethylenic structure as set forth above.

The invention therefore also relates to a process for preparing a high impact polypropylene composition suitable for the manufacture of electronic and automotive parts, which process comprises: providing a masterbatch which comprises a mixture of a low molecular weight brominated epoxy of Formula (I), a carrier polymer which is one or more high molecular weight brominated epoxy polymers of Formula (I), as set forth above, and optionally a compatibilizer having a polyethylenic structure, an inert polymer carrier and inorganic synergist such as antimony trioxide; and processing said masterbatch with the high impact polypropylene, and optionally also with said compatibilizer and/or synergist if the latter are not present in said masterbatch, to form a high impact polypropylene composition in which the bromine content is preferably in the range between 4 and 10 wt. % and the inorganic synergist (e.g., antimony trioxide) concentration is in the range between 0 and 3 wt. %.

In addition to the high impact polypropylene, the mixture of brominated epoxy polymers which function as flame retardants, the compatibilizer and the inorganic synergist (e.g., antimony trioxide), the composition of this invention may contain conventional ingredients, such as fillers, smoke-suppressants, glass reinforcement, impact modifiers, pigments, UV stabilizers, heat stabilizers, lubricants and antioxidants. The concentration of each of the additives listed above is typically in the range between 0 and 30 wt. %.

In a specific embodiment there is provided injection molded components, e.g., electronic or automotive components, comprising a high impact polypropylene and a flame retardant additive composition, which composition comprises low molecular weight brominated epoxy polymer or end-capped low molecular weight brominated epoxy polymer, high molecular weight brominated epoxy polymer, and at least one compatibilizer having a polyethylenic structure or a compatibilizer which is phosphatotitanante, and an inorganic synergist such as antimony trioxide.

In another embodiment there is provided a flame retarded article, e.g., an electronic or automotive component, preferably an injection molded electronic component, as described herein, made by the above-described method.

The following examples are used to illustrate the present invention. The compositions are defined in terms of weight percent, unless otherwise indicated. EXAMPLES

Materials

The materials used in the following examples are presented in Table 1.

TABLE 1

TRADE NAME (Supplier) GENERAL INFORMATION FUNCTION

ASI Polypropylene 1404-01 Polypropylene Impact Copolymer Plastic matrix (A. Schulman)

F-2400 (ICL-IP) High Mw brominated epoxy polymer FR

F-2016 (ICL-IP) Low Mw brominated epoxy polymer FR

F-3020 (ICL-IP) Low Mw brominated epoxy polymer end- FR

capped with tribromophenol

FR-01 120 LD (ICL-IP) Antimony trioxide master batch (80%) FR synergist

Irganox B225 (Ciba) IRGAFOS 168 and IRGANOX 1010 Thermal

50/50 blend stabilizer

Joncryl ADR-4300 (BASF) Epoxy modified acrylic copolymer Compatibilizer

Joncryl ADR 4385 (BASF) Epoxy modified acrylic copolymer Compatibilizer

Epolene C-26 (Westlake) Polyethylene-MA modified copolymer Compatibilizer

Epolene E-25 (Westlake) Polypropylene-MA modified copolymer Compatibilizer

Epolene-E-43 (Westlake) Polypropylene-MA modified copolymer Compatibilizer

Lotader 8840 (Arkema) Ethylene-glycidyl methacrylate Compatibilizer copolymer (epoxy modified PE)

Lotader 5500 (Arkema) Ethylene-ethyl acrylate-MA-copolymer Compatibilizer

Orevac 18720 (Arkema) MA modified polypropylene Compatibilizer

Baker X- 10016 (Baker Hughes) Maleated propene homopolymer Compatibilizer

Baker X- 10082 (Baker Hughes) Maleated propene homopolymer Compatibilizer

Baker X-10083 (Baker Hughes) Maleated propene homopolymer Compatibilizer

Baker X-10122 (Baker Hughes) Epoxidized 1 - propene homopolymer Compatibilizer

Integrate NP507030 (Equistar) Propylene-MA modified copolymer Compatibilizer

Fusabond P353 (DuPont) Propylene-MA modified copolymer Compatibilizer

Fusabond P613 (DuPont) Propylene-MA modified copolymer Compatibilizer

Admer AT2543A (Mitsui Polyethylene-MA modified copolymer Compatibilizer Chemicals)

Ken-React CAPS L12/L (Kendrich Neopentyl(diallyl)oxy, Compatabilizer Petrochemicals) tri(dioctyl)phosphate titanate LLDPE

masterbatch Test Methods

Tests employed in this work are summarized in Table 2.

TABLE 2

Examples 1-10 and comparative examples 1C-13C Preparation and testing of flame retarded high impact polypropylene

1. Compounding

Compounding was performed using a C. W. Brabender conical twin screw co-rotating extruder with an L/D = 10.6. Residence time was established at 30 seconds. The extrudate was water cooled and pelletized using a Conair Model 304. The material was dried in a forced air oven at 75 °C for 4 hours prior to molding. The compounding conditions are presented in Table 3.

TABLE 3

2. Injection Molding

Test specimens were prepared by injection molding using an Arburg 270S Allrounder 250-150. The conditions of the injection molding are presented in Table 4. TABLE 4 Regime of injection molding in Arburg 270S Allrounder 250-150

3. Conditioning

Specimens were conditioned at 23°C and 50% RH for 48 hours prior to UL-94 and mechanical property testing.

4. Results

Table 5 shows examples of high impact polypropylene compositions flame retarded with the blend of low molecular weight and high molecular weight brominated epoxy polymers. All compositions contain 8 wt. % Br with 6 wt. % Br coming from low molecular weight brominated epoxy polymer and 2 wt. % coming from high molecular weight brominated polymer. All compositions contain 2.64 wt. % antimony trioxide being compounded as 3 wt. % of 80% masterbatch. As it is seen from Table 5 all compatibilizers with polyethylenic structure or phosphatotitanate (examples 1-10) provide significant improvement in Izod impact strengths (> 400 J/m) compared to the composition without a compatibiiizer (70 J/m, comparative example 1C).

Table 6 shows comparative examples of high impact polypropylene compositions containing compatibilizers having polypropylenic and other non-polyethylenic structures. As it is seen from this table, non polyethylenic compatibilizers provide only moderate improvement in Izod impact strength (< 175 J/m, comparative examples 2C-13C) compared to the composition without compatibiiizer (70 J/m, comparative example 1C) and these Izod impact values are much lower than those of the non flame retarded polymer (585 J/m, Table 5).

TABLE 5

TABLE 6

Example 2C 3C 4C 5C 6C 7C 8C 9C IOC l ie 12C 13C

Compatilizer Baker Baker Baker Baker Fusabond Fusabond Joncryl Joncryl Orevac Integrate Epolene Epolen

XI 0082 XI 0083 X10016 X10122 P353 P613 ADR- ADR- 18720 507030 E-43 E-25

4300F 4380

PP 77.7 77.7 77.7 77.7 77.7 77.7 77.7 77.7 77.7 77.7 77.7 77.7

F-2400 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2

F-2016 12.6 12.6 12.6 12.6 12.6 12.6 12.6 12.6 12.6 12.6 12.6 12.6

A01120 LD 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.3

Compatibilizer 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0

Irganox B225 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2

UL-94 rating V-2 V-2 V-2 V-2 V-2 V-2 V-2 V-2 V-2 V-2 V-2 V-2

Izod Impact 95 105 1 6 100 120 118 91 174 137 128 92 90

Example 11-12

Preparation of masterbatch compositions of flame retardants

The next examples illustrate that the composition of the invention [comprising (a) high molecular weight brominated epoxy polymer, (b) low molecular weight brominated epoxy polymer and (c) a compatibilizer having polyethylenic structure] can be produced in a masterbatch form using a twin screw extruder.

Two masterbatch compositions of flame retardants were prepared according to Table 7. Compounding of the masterbatch compositions was performed using a C. W. Brabender conical twin screw co-rotating extruder with an L/D = 10.6. Residence time was established at 30 seconds. The extrudate was composed of strands of about 1-.1.5 inches long which were dropped and cooled in water. The material was dried in a forced air oven at 75 °C for 4 hours prior to molding. The strands required further size reduction prior to blending with polypropylene pellets. It was done by Conair Model 304 pelletizer. The compounding conditions are presented in Table 8.

TABLE 7

TABLE 8

Examples 13-14 (high impact polypropylene made through a masterbatch route) and 15-16 (high impact polypropylene made through separate addition of the components^')

Examples 13-14 illustrate that the compositions of the invention can be applied in a masterbatch form in the preparation of high impact polypropylene. The resultant polymer formulations meet the UL-94 V-2 rating. Thus, the masterbatch route can be employed, as an alternative to the compounding of high impact polypropylene based on the separate addition of the flame retardants and compatibilizer (see Example 15- 16).

1. Compounding

Compounding was performed using a C. W. Brabender conical twin screw co-rotating extruder with an L D = 10.6. Residence time was established at 30 seconds. The extrudate was water cooled and pelletized using a Conair Model 304. The material was dried in a forced air oven at 75°C for 4 hours prior to molding. The compounding conditions are presented in Table 9.

TABLE 9

2. Injection Molding

Test specimens were prepared by injection molding using an Arburg 270S AUrounder 250-150, the injection molding conditions are presented in Table 10. TABLE 10 Regime of injection molding in Arburg 270S Allrounder 250-150

3. Conditioning

4. Results

The results are presented in Table 11. It may be appreciated that high impact polypropylene compositions prepared through the masterbatch route (Examples 13 and 14) and high impact polypropylene compositions produced by means of separate addition of the components (Examples 15 and 16) are equally good in terms of flame retardancy, being assigned the UL-94 V-2 rating.

TABLE 11

Examples 13 14 15 16

PP (ASI 1404-1) 77.7 79.0 77.7 79.0

Masterbatch of Example 11 18.8 -

Masterbatch of Example 12 - 17.5 -

F-2400 3.2 2.9

F-2016 12.6

F-3020 11.6

Epolene C-26 3.0 3.0

A01120 LD 3.3 3.3 3.3 3.3

Irganox B225 0.2 0.2 0.2 0.2

UL-94

Vertical, 1.6 mm V-2 V-2 V-2 V-2

Total burn time 72 56 60 37

Maximum burn time 14 11 14 6

Drips Yes Yes Yes Yes

Claims

1. A flame retardant additive composition comprising:

(a) at least one high molecular weight brominated epoxy polymer or its end-capped derivative having average molecular weight above 5000;

(b) at least one low molecular weight brominated epoxy polymer or its end-capped derivative having average molecular weight of less than 2500;

(c) at least one compatibilizer, said compatibilizer either having polyethylenic structure or is organotitanate.

2. The flame retardant additive composition of claim 1 wherein the high molecular weight brominated epoxy polymer is represented by Formula (I):

wherein n, the average degree of polymerization, is in the range from 24 to 115, and o

R¹ and R² are glycidyl ether groups of the structure ^{H2C—CH— C il2} .

3. The flame retardant additive composition of claims 1 or 2, wherein the high molecular weight brominated epoxy polymer has average molecular weight in the range from 40000 to 60000.

4. The flame retardant additive composition of claim 1 wherein the high molecular weight brominated epoxy polymer is present in the amount from about 10 wt. % to about 50 wt. % of the total weight of said flame retardant composition.

5. The flame retardant additive composition of claim 4 wherein the high molecular weight brominated epoxy polymer is present in the amount from about from about 10 wt. % to about 30 wt. % of the total weight of the flame retardant composition.

6. The flame retardant additive composition according to any one of the preceding claims wherein the low molecular weight brominated epoxy polymer and its end-capped derivative is represented by Formula (I):

wherein n, the average degree of polymerization, is in the range from 0.5 to 7.2 and

R 1 and R 2 are independently selected from the group consisting of glycidyl ether groups

O

H₂C— CH-CH₂

or 2-hydroxypropyltribromophenol ether groups

7. The flame retardant additive composition of claim 6 wherein the low molecular weight brominated epoxy polymer or its end-capped derivative have average molecular weight in the range from 1000 to 2100.

8. The flame retardant additive composition of claim 1 wherein the low molecular weight brominated epoxy polymer or its end-capped derivative is present in the amount from about 30 wt. % to about 80% wt. % of the total weight of the flame retardant composition.

9. The flame retardant additive composition of claim 8 wherein the low molecular weight brominated epoxy polymer or its end-capped derivative is present in the amount from about 40% wt. % to about 70% wt. % of the total weight of the flame retardant composition.

10. The flame retardant additive composition according to any one of the preceding claims wherein the compatibilizer has polyethylenic structure.

1 1. The flame retardant additive composition according to claim 10 wherein the compatibilizer is a copolymer of ethylene and a second, polar monomer.

12. The flame retardant additive composition according to claim 1 1 wherein the second monomer is maleic anhydride.

13. The flame retardant additive composition of claim 10 wherein the compatibilizer is selected from the group consisting of maleic anhydride functionalized high-density polyethylene, maleic anhydride functionalized low- density polyethylene or maleic anhydride functionalized linear low density polyethylene.

14. The flame retardant additive composition of claim 10 wherein the compatibilizer is selected from the group consisting of copolymers of ethylene and a second monomer bearing epoxy groups.

15. The flame retardant additive composition of claim 14 wherein the monomer is glycidyl methacrylate.

16. The flame retardant additive composition of claim 1 wherein the compatibilizer is phosphatotitanate.

17. The flame retardant additive composition of claim 16 wherein the phosphatotitanate is neopentyl(diallyl)oxy tri(dioctyl phosphate) titanate.

18. The flame retardant additive composition of claim 1 wherein the compatibilizer is present in the amount from about 2 wt. % to about 20% wt. % of the total weight of the flame retardant composition.

19. The flame retardant composition of claim 1 further containing inorganic synergist, selected from the group of inorganic antimony, inorganic bismuth, inorganic tin, inorganic iron or inorganic zinc compounds.

20. The flame retardant composition of claim 19 wherein the inorganic antimony compound is selected from the group of antimony trioxide, antimony pentoxide or sodium antimonite.

21. The flame retardant composition according to any one of the preceding claims, wherein said flame retardant composition is provided in the form of a masterbatch comprising a combination of the brominated epoxy polymers, the compatibilizer and optionally antimony trioxide.

22. A masterbatch composition according to claim 21, comprising high molecular weight brominated epoxy of Formula I with molecular weight from 40000 to 60000, low molecular weight brominated epoxy or its end-capped derivative of Formula I with molecular weight from 1000 to 2100 and a compatibilizer having polyethylenic structure.

23. A masterbatch composition according to claim 22, wherein the compatibilizer is as defined in claims 11 to 15.

24. A flame retarded high impact polypropylene composition comprising the flame retardant composition defined in any one of the preceding claims.

25. The flame retarded high impact polypropylene composition of claim 24 with bromine content of about 4 wt. % to about 10 wt. % based on the total weight of the high impact polypropylene composition

26. The flame retarded high impact propylene composition of claim 25 further comprising from about 0.5 wt. % to about 3 wt. % of antimony trioxide based on the total weight of the high impact polypropylene composition.

27. A process of preparing flame retarded high impact polypropylene composition comprising blending high impact polypropylene and the components of the flame retardant composition of claim 1 and processing the resultant mixture by extrusion,

28. A process of preparing of flame retardant high impact polypropylene composition according to claim 27, wherein at least two of the components of the flame retardant composition are provided in the form of a masterbatch.

29. Injection molded components, comprising the high impact polypropylene composition of claim 24.