FLAME RETARDANT COMPOSITION AND INSULATED WIRES FOR USE IN ELECTRONIC EQUIPMENT

Abstract

This invention relates to a flame retardant composition comprising Component (A) being a thermoplastic copolyester elastomer comprising 20 to 80 wt. % of monomeric units derived from a dimerised fatty acid or a derivative thereof and further monomeric units derived of at least one dicarboxylic acid and at least one diol, wherein wt % is with respect to the total weight of the thermoplastic copolyester elastomer; and Component (B) being a metal salt of a phosphinic acid of the formula [R.sup.1R.sup.2P(O)O]-.sub.mM.sup.m+ (formula I) and/or a diphosphinic acid of the formula [O(O)PR.sup.1—R.sup.3—PR.sup.2(O)O].sup.2-.sub.nM.sub.x.sup.m+ (formula II), and/or a polymer thereof, wherein —R.sup.1 and R.sup.2 are equal or different substituents chosen from the group consisting of hydrogen, linear, branched and cyclic C1-C6 aliphatic groups, and aromatic groups, —R.sup.3 is chosen from the group consisting of linear, branched and cyclic C1-C10 aliphatic groups and C6-C10 Caromatic and aliphatic-aromatic groups, —M is a metal chosen from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, and K, and —m, n and x are equal or different integers in the range of 1-4; as well as an insulated wire for use in electronic equipment, comprising an electrically conductive core and an insulating layer and/or an insulating jacket comprising or consisting of the flame retardant composition.

Claims

1. Flame retardant composition comprising Component (A) being a thermoplastic copolyester elastomer comprising 20 to 80 wt. % of monomeric units derived from a dimerised fatty acid or a derivative thereof and further monomeric units derived from at least one dicarboxylic acid and at least one diol, wherein wt % is with respect to the total weight of the thermoplastic copolyester elastomer; and Component (B) being a metal salt of a phosphinic acid of the formula [R.sup.1R.sup.2P(O)O].sup.−.sub.mM.sup.m+ (formula I) and/or a diphosphinic acid of the formula [O(O)PR.sup.1—R.sup.3—PR.sup.2(O)O].sup.2−.sub.nM.sub.x.sup.m+ (formula II), and/or a polymer thereof, wherein R.sup.1 and R.sup.2 are equal or different substituents chosen from the group consisting of hydrogen, linear, branched and cyclic C1-C6 aliphatic groups, and aromatic groups, R.sup.3 is chosen from the group consisting of linear, branched and cyclic C1-C10 aliphatic groups and C6-C10 aromatic and aliphatic-aromatic groups, M is a metal chosen from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, and K, and m, n and x are equal or different integers in the range of 1-4.

2. Flame retardant composition according to claim 1, further comprising component (C) being a styrenic block copolymer and/or an olefinic thermoplastic elastomer.

3. Flame retardant composition according to claim 2, wherein component (C) is present in at least 15 wt % relative to the total weight of the flame retardant composition.

4. Flame retardant composition according to claim 1, further comprising a component (G), being a thermoplastic polymer different from component (A) and (C), component (G) being a polyester, polyamide, polycarbonate, copolyester elastomer (TPE-E), copolyamide elastomer (TPE-A), copolyurethane elastomer (TPE-U), olefinic polymer, as well as combinations thereof.

5. Flame retardant composition according to claim 1, further comprising component (D) being a nitrogen containing flame retardant synergist and/or a phosphor/nitrogen containing flame retardant.

6. Flame retardant composition according to claim 1, further comprising component (E) being a basic and amphoteric oxides, hydroxides, carbonates, silicates, borates, stannates, mixed oxide-hydroxides, oxide-hydroxide-carbonates, hydroxide-silicates and hydroxide-borates, and mixtures thereof.

7. Flame retardant composition according to claim 1 wherein the amounts are as follows with wt % relative to the total weight of flame retardant composition; 30 wt % to 80 wt % component (A); 5 wt % to 25 wt % component (B); 0 wt % to 40 wt % component (C); 0 wt % to 20 wt % component (D); 0 wt. % to 5 wt. % component (E); 0 wt. % to 10 wt % component (F); 0 wt % to 10 wt % component (G).

8. Flame retardant composition according to claim 1, wherein the flame retardant composition consists essentially of, expressed as wt % relative to the total weight of the flame retardant composition unless denoted otherwise: Component (A) in an amount of between 30 wt % to 80 wt % of a thermoplastic copolyester elastomer, comprising 20 to 80 wt. %, wherein wt % of monomeric units is with respect to the total weight of the thermoplastic copolyester elastomer, of monomeric units derived from a dimerised fatty acid or a derivative thereof and further monomeric units derived of at least one dicarboxylic acid and at least one diol; Component (B) in an amount of between 5 wt % to 25 wt % of a metal salt of a phosphinic acid of the formula [R.sup.1R.sup.2P(O)O].sup.−.sub.mM.sup.m+ (formula I) and/or a diphosphinic acid of the formula [O(O)PR.sup.1—R.sup.3—PR.sup.2(O)O].sup.2−.sub.nM.sub.x.sup.m+ (formula II), and/or a polymer thereof, wherein R.sup.1 and R.sup.2 are equal or different substituents chosen from the group consisting of hydrogen, linear, branched and cyclic C1-C6 aliphatic groups, and aromatic groups, R.sup.3 is chosen from the group consisting of linear, branched and cyclic C1-C10 aliphatic groups and C6-C10 aromatic and aliphatic-aromatic groups, M is a metal chosen from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, and K, and m, n and x are equal or different integers in the range of 1-4; and optionally Component (C) in an amount of between 0 wt % to 40 wt % of styrenic block copolymer and/or an olefinic thermoplastic elastomer; and Component (D) in an amount of between 0 wt. % to 20 wt % of a nitrogen containing flame retardant synergist and/or a phosphor/nitrogen containing flame retardant; and Component (E) in an amount of between 0 wt. % to 5 wt. % of basic and amphoteric oxides, hydroxides, carbonates, silicates, borates, stannates, mixed oxide-hydroxides, oxide-hydroxide-carbonates, hydroxide-silicates and hydroxide-borates, and mixtures thereof; and Component (F) being further additives in an amount of between 0 wt % to 10 wt %; and Component (G) being a thermoplastic polymer different from components (A) and (C), and being a copolyester elastomer, a copolyamide elastomer, a copolyurethane elastomer, polyolefin and combinations thereof, in an amount of between 0 wt % to 10 wt %; wherein the total weight of all components add up to 100%.

9. Flame retardant composition according to claim 1, wherein the flame retardant composition consists essentially of, expressed as wt % relative to the total weight of the flame retardant composition unless denoted otherwise: Component (A) 35 wt % to 50 wt % being a thermoplastic copolyester elastomer comprising 20 to 80 wt. %, wherein wt % of monomeric units is with respect to the total weight of the thermoplastic copolyester elastomer, of monomeric units derived from a dimerised fatty acid or a derivative thereof and further monomeric units derived of at least one dicarboxylic acid and at least one diol; and Component (B) 10 wt % to 20 wt % being a metal salt of a phosphinic acid of the formula [R.sup.1R.sup.2P(O)O].sup.−.sub.mM.sup.m+ (formula I) and/or a diphosphinic acid of the formula [O(O)PR.sup.1—R.sup.3—PR.sup.2(O)O].sup.2−.sub.nM.sub.x.sup.m+ (formula II), and/or a polymer thereof, wherein R.sup.1 and R.sup.2 are equal or different substituents chosen from the group consisting of hydrogen, linear, branched and cyclic C1-C6 aliphatic groups, and aromatic groups, R.sup.3 is chosen from the group consisting of linear, branched and cyclic C1-C10 aliphatic groups and C6-C10 aromatic and aliphatic-aromatic groups, M is a metal chosen from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, and K, and m, n and x are equal or different integers in the range of 1-4, and Component (C) 20 wt % to 35 wt % being a styrenic block copolymer and/or an olefinic thermoplastic elastomer; and Component (D) 5 wt. % to 15 wt. % being a nitrogen containing flame retardant synergist and/or a phosphor/nitrogen containing flame retardant. Component (E) 0 wt. % to 5 wt. % of basic and amphoteric oxides, hydroxides, carbonates, silicates, borates, stannates, mixed oxide-hydroxides, oxide-hydroxide-carbonates, hydroxide-silicates and hydroxide-borates, and mixtures thereof; and Component (F) 0 wt % to 10 wt % being additives; and Component (G) 0 wt % to 10 wt % being a thermoplastic polymer different from components (A) and (C), and being a copolyester elastomer, a copolyamide elastomer, a copolyurethane elastomer, polyolefin and combinations thereof; wherein the total weights of all components add up to 100%.

10. Flame retardant composition according to claim 1, wherein component (B) and the component (D) are present in a weight ratio in the range of 9:1-2:9.

11. An insulated wire for use in electronic equipment, comprising an electrically conductive core and an insulating layer and/or an insulating jacket comprising or consisting of a flame retardant composition surrounding the electrically conductive core, wherein the flame retardant composition is the flame retardant composition according to claim 1.

12. The insulated wire according to claim 11, wherein the insulated wire is a bipolar or tripolar wire consisting of two or three electrically conductive cores, two or three insulating layers each surrounding one of the electrically conductive cores, and optionally a jacket layer surrounding the electrically conductive cores and the insulating layers, wherein the insulating layers and/or the jacket layer consist of the flame retardant composition.

13. A connection cable comprising (i) a piece of an insulated wire according to claim 11 and (ii) one or two connection elements, for connecting the cable to electrical and/or electronic equipment and/or to a power supply unit, fixed to the piece of insulated wire and optionally (iii) an electrical or electronic part.

14. The connection cable of claim 13, wherein the connection cable is a mobile phone charger cable or computer accessory connection cable.

Description

SPECIAL EMBODIMENTS

[0120] The combination of component (A), and flame retardants (B) and optionally component (C), (D), (E) provide a unique combination of flame retardant properties, mechanical and electrical properties all achieved while providing an insulated cable with enhanced consumer appeal as indicated by softness, surface feel and appearance, flexibility and density. In addition, the effectiveness of both the flame retardant component (B) and (D) to impart flame retardant properties and the styrenic block copolymer and/or olefinic thermoplastic elastomers component (C) to impart consumer properties, enables the flexibility of additional components to be added to improve the other functionalities such as processability, thermal resistance, mechanical strength, and surface appearance and feel.

[0121] A higher minimal total weight for components (B), and optionally (D) and/or (E) has the advantage that even better flame retardancy properties are obtained. A lower maximum total weight for components (B) optionally (D) and/or (E) has the advantage that the insulated wires have an improved softness and flexibility. Further, the relatively low levels of flame retardants required under the scope of the present invention enables a greater flexibility to tailor specific formulations to specific need use applications while maintaining the required flame retardant, mechanical, electrical, heat resistant and consumer appeal properties.

[0122] For instance, as another embodiment of the present invention there is provided an insulated wire for use in electronic equipment, comprising an electrically conductive core and an insulating layer and/or an insulating jacket comprising or even consisting of a flame retardant composition surrounding the electrically conductive core, wherein the flame retardant composition the formulation (%. wt expressed relative to the total weight of the flame retardant composition) essentially consists of:

[0123] 30 wt % to 80 wt % component (A), preferably 35 to 50 wt %;

[0124] 5 wt % to 25 wt % component (B), preferably 10 to 20 wt %;

[0125] 0 wt % to 40 wt % component (C), preferably 20 to 35 wt %;

[0126] 0 wt % to 20 wt % component (D), preferably 5 to 15 wt %;

[0127] 0 wt. % to 5 wt. % component (E); preferably 0 to 4 wt %;

[0128] 0 wt. % to 10 wt % component (F);

[0129] 0 wt % to 10 wt % component (G).

[0130] The components refer to the description above, including all preferred embodiments.

[0131] The combined level of the flame retardant components (B) and (D) is preferably between 20 wt % and 40 wt. % and more preferably between 25 wt % and 35 wt. % relative to the total weight of the flame retardant composition.

[0132] Preferably, component (C) is in the range of 20 wt. % to 40 wt. % and more preferably 20 wt. % to 35 wt. % relative to the total weight of the flame retardant composition.

[0133] This composition is able to comply with the UL 1581 VW-1 standard, especially when the proportion of flame retardants (B) and (D) are at the upper range limit (i.e 25 wt. % to 35 wt. % (B) and (D) combined), while lower flame retardant standards are maintainable at lower levels of component (B) and optionally (D) and/or (E). The relatively lower levels of the flame retardant system (B), (D) and (E) result in a relatively lighter (lower density) cable, compared to other non-halogen flame retardant systems, which has the mechanical and consumer appeal properties associated with the styrenic block copolymer and optionally the olefins.

[0134] If component (C) is a TPO, the combined level of flame retardant components (B) and (D) is preferably increased to between 20 wt % to 40 wt %.

[0135] Preferably, the insulation resistance in water is greater than 0.5, 0.75, 1.0, 1.5 or 2.0 GΩm.

[0136] Preferably, the elongation at break, determined according to ISO 527/1A, of the flame retardant composition is at least 200%, 300%, 400%, 500% or even at least 600%.

[0137] Preferably, the E-modulus, determined according to ISO 527/1A, of the flame retardant composition is less than 150, 100 MPa, 90 MPa, 80 MPa, 70 MPa 60 MPa, 50 MPa or 40 MPa. Preferably, the composition has a minimum E-Modulus of at least 5 MPa and more preferably at least 10 MPa, to enable the cable to have sufficient rigidity to perform its function.

[0138] Preferably, the yield stress, determined according to ISO 527/1A, is less than 12 MPa, more preferably less than 6 MPa, more preferably less than 5 MPa and even more preferably less than 4 MPa. Preferably, the composition has a minimum yield stress of at greater 1.2 MPa and more preferably at greater 1.8 MPa, to enable the cable to have sufficient rigidity to perform its function.

[0139] Preferably the Shore A hardness, determined according to DIN 53505, is less than 95, 90, 85, 80, 70, 60, 50 or 40.

[0140] Preferably the Shore D hardness, determined according to ISO R 868, is less than 50, 45, 40, 36, 34, 33, 32 or 31.

[0141] Preferably, the roughness (Ra) of the cable surface is less than 11 Ra, more preferably less than 8 Ra, more preferably less than 6 Ra, more preferably less than 5 Ra, more preferably less than 4 Ra, even more preferably less than 3 Ra and most preferably less than 2 Ra.

[0142] The combination of elasticity (% elongation at break), softness (low Shore A hardness), flexibility (low E modulus and yield stress) and/or smoothness (low roughness Ra) are mechanical properties of particular importance to the consumer appeal of the resultant insulated wire or product derived therefrom.

[0143] The invention in particular relates to an insulated wire wherein the insulated wire is a bipolar or tripolar wire consisting of two or three electrically conductive cores, two or three insulating layers each surrounding one of the electrically conductive cores, and optionally a jacket layer surrounding the electrically conductive cores and the insulating layers, wherein the insulating layers and/or the jacket layer consist of the flame retardant composition comprising components (A) (B) and optionally (C), (B) and (C) or any preferred embodiment thereof as described above.

[0144] The invention also relates to a connection cable comprising (i) a piece of an insulated wire according to the invention or any preferred embodiment thereof and (ii) one or two connection elements, for connecting the cable to electrical and/or electronic equipment and/or to a power supply unit, fixed to the piece of insulated wire and optionally (iii) a electrical or electronic part.

[0145] Suitably, the connection cable is a mobile phone charger cable or computer accessory connection cable.

[0146] The invention further relates to the use of the inventive insulated wires and connection cables made thereof in or connected to electronic equipment and to electronic equipment comprising insulated wires according to the invention, or any preferred embodiment thereof.

[0147] The invention also relates to a flame retardant composition. The flame retardant composition according to the invention corresponds with the flame retardant composition in the insulated wire according to the invention described here above, and any of the preferred embodiments thereof. The advantage of the flame retardant composition according to the invention resides in the combined effects on flame retardancy and consumer appeal properties, in addition to other effects when the flame retardant composition is applied in electrical cables as described above.

[0148] The flame retardant composition can be made by compounding methods used in the art for making flame retardant compositions in general and elastomeric thermoplastic compositions in particular. Suitable methods include methods involving melt mixing, i.e. methods wherein component (A) and optionally component (C) are transformed into a melt and the components (B) and other optional components are added, simultaneously, consecutively or partly simultaneously and partly consecutively to the component (A) and optionally component (C) prior, during or after the transformation into the melt and the polymer melt and other components and additives are mixed to form a homogenous mixture.

[0149] Suitably, this melt mixing is performed in an extruder and the homogenous mixture after being formed by said melt mixing is discharged from the extruder after which the composition is cooled and optionally granulated.

[0150] It is also possible to add the flame retardant components and the additives in the form of a master batch. It is also possible, in particular with solid additives, to add the additive or additives after cooling and optional granulation, whereby the additive or additives is applied on the granule surface.

[0151] The cooled and optionally granulated composition can be used for making the insulated wires, for example by extrusion coating of one or more metal wires which than form the electrically conductive core of the resulting insulated wires.

[0152] The invention is further illustrated with the following Examples and Comparative Experiments.

Examples

Materials

[0153] Component (A): Thermoplastic copolyester elastomer comprising 50 wt % monomeric units derived from a dimerised fatty acid and further monomeric units derived of terephthalic acid and 1,4-butanediol, wherein wt % is with respect to the total weight of the thermoplastic copolyester elastomer. Shore-D hardness is 34. [0154] Component (B): Exolit OP1230: Aluminium diethylphosphinate; Clariant, Germany. [0155] Component (C): Styrenic block copolymer available from Kraton under the trade name Kraton SEBS1536 HS. [0156] TPE-E: Polyetherester elastomer (TPE-E) comprising hard segments consisting of polybutyleneterephthalate segments and soft segments consisting of poly(tetramethylene glycol). Shore-D hardness is 33. [0157] Component (D): Melapur® 200 (MPP): Melamine polyphosphate; Ciba Geigy, Switzerland. [0158] Component (E): Zinc Borate (2 ZnO.sub.3B.sub.2O.sub.3.3.5H.sub.2O), Firebrake® 500, Borax, USA [0159] Add F1: Blend of auxiliary stabilizer package. [0160] Add F2: Silicon gum comprising ultrahigh-molecular-weight polydimethylsiloxane in pellet form available from Wacker under the trade name Genioplast® Pellet S.

Compounding

[0161] For the preparations of moulding compositions, ingredients were compounded in ratios as indicated in Tables 1 to 3. The moulding compositions were prepared by melt-blending the components A and optionally C with the flame retardant components and stabilizer package on a ZSK 25/33 screw speed 400 rpm respectively, throughput of 25 kg/hr, and melt temperature regulated at <260° C., extruding the melt from the extruder through a die, and cooling and granulating the melt. The granules obtained by compounding in the extruder were dried for 24 hours at 90° C., prior to further use.

Moulding of Test Samples and Insulated Cables

[0162] Test samples for testing the mechanical properties and the flame retardancy properties according to UL-94-V (1.5 mm thickness) were prepared on an injection-moulding machine of type Engel 80 A. For the injection moulding set temperatures of 200-230° C. were used.

[0163] Insulated cables for testing the flame retardancy properties according to UL 1581 VW-1 were prepared on an industrial production line under comparable operating conditions at a speed of between 50 to 100 m/min. The cables thus produced included: [0164] Cable 1: Insulated 18AWG cable. This cable is used in NC power cable type applications. [0165] Cable 2: Insulated jacketed SVE cable containing 3 cores of Insulated 18AWG cable. This cable is used for NC power cable type applications.

Test Methods

Mechanical Properties:

[0166] Tensile tests (E-modulus, Stress at yield and elongation at break) were performed according to ISO 527/1A using dry-as-moulded samples. Dimensions of tensile test specimens: thickness 4 mm.
Shore A hardness, according to DIN 53505

Flame Retardancy

[0167] Sample preparation and testing was performed according to UL1581 VW-1. Three individual samples were measured for each cable sample and the after contact burn time for each of the five flame contacts was recorded. The sum of the 5 burn times was defined as the total burn time of an individual sample. The average total burn time of all three individual samples was determined for each cable sample and used to compare the flame retardancy performance across different cables samples in a quantitative manner.

[0168] Compositions according to the invention, Examples 1 to 5 (E1-E5) and Comparative Experiments A and B (CEA, CE-B) were prepared and tested as described above. The compositions and test results are presented in Table 1.

TABLE-US-00001 TABLE 1 Compositions and results for Examples 1-5 and Comparative Experiments A and B CE-A Example 1 Example 2 CE-B Example 3 Example 4 Example 5 Compositions (wt %) Component (A) 46.0 48.1 38.5 43.0 74.0 TPE-E 46.0 38.5 Component (B) 14.2 14.2 13.3 19.0 19.0 17.0 14.2 Component (C) 25.0 25.0 25.0 30.0 30.0 30.0 Component (D) 7.1 7.1 6.7 9.5 9.5 8.5 7.1 Component (E) 0.8 0.8 1.5 1.5 0.0 0.8 Add F1 5.4 5.4 5.4 1.6 1.6 1.6 2.4 Add F2 1.5 1.5 1.5 1.5 Total 100 100 100.0 100.0 100.0 100.0 100.0 Mechanical Results Tensile strength (MPa) 9.4 9.2 8.3 11.1 7.7 7.4 8.7 E-modulus (MPa) 49 54 52 53 78 56 83 Elongation at break (%) 410 381 324 433 256 307 318 shore-A hardness 89 91 91 90 92 91 95 Mechanical retentions after heat aging (121° C., 168 hrs) Tensile strength (% ret.) 104 112 110 113 114 112 97 Elongation at break (% ret.) 93 112 108 105 113 110 75 Cable results Cable type Cable 2 Cable 2 Cable 2 Cable 1 Cable 1 Cable 1 Cable 2 Av. Total burn time VW-1 (s) 55 30 28 14 13 15 23

Results

[0169] The results summarized in Table 1 show that all compositions yield insulated wires with a sufficient consumer appeal while maintaining a sufficient combination of flame retardant and mechanical properties to satisfy UL62 norm requirements. Surprisingly, however, when comparing Example 1 with CE-A and

[0170] Example 3 with CE-B, it is clear that the compositions comprising Component (A) give rise to much improved flame retardancy properties. In addition, heat aging properties of the compositions according to the invention are excellent (mechanical retentions >100%. Even more surprisingly, Example 2 and 4 illustrate that compositions according to the invention allow significantly lower amounts of flame retarding components (B), (D) and (E), while maintaining the flame retardancy properties at approximately the same, improved level. This leads to better processability, higher overall consumer appeal and lower ecological footprint of the compositions and the ensuing insulating wires. Example 5 does not contain component (C), which has the advantage that the composition exhibits the highest level of biorenewable content, while still exhibiting sufficient flame retardant properties.