Halogen-free flame retardant thermoplastic polyurethane elastomer composition and product and flame retardant package thereof

Abstract

A halogen-free flame retardant thermoplastic polyurethane elastomer composition and product and flame retardant package thereof comprised thermoplastic polyurethane and halogen-free flame retardant package. The halogen-free flame retardant comprises inorganic phosphorus-based flame retardant and can further comprise expandable graphite, melamine or derivatives thereof and organic phosphorus-based flame retardant. The composition is environmentally friendly and safe, the comprehensive mechanical properties thereof are excellent, does not drip during the burning test, passed UL94 with rating of V0−1.5 mm, and the limiting oxygen index thereof can be up to 35%.

Claims

1. A halogen-free flame retardant thermoplastic polyurethane elastomer composition comprising a thermoplastic polyurethane and a halogen-free flame retardant composition comprising, based on the weight of the thermoplastic polyurethane: inorganic hypophosphite selected from lanthanum hypophosphite, yttrium hypophosphite, or a mixture thereof: 10-45 wt %; expandable graphite: 2-7 wt %; melamine or derivatives thereof: 7-13 wt %; and organic phosphorus-based flame retardant: 4-25 wt %; wherein the organic phosphorus-based flame retardant has the structural formula of ##STR00008## wherein R is ##STR00009##  or meta-substituted benzene ring; n is an integer from 1 to 10; X.sub.1, X.sub.2, X.sub.3 and X.sub.4 are the same or different and are phenyl or a C6-C18 aryl group containing 1 to 3 C1-C2 alkyl substituent respectively; and wherein the thermoplastic polyurethane is polyether-based thermoplastic polyurethane.

2. The halogen-free flame-retardant thermoplastic polyurethane elastomer composition according to claim 1, characterized in that the initial expansion temperature of the expandable graphite is 200° C. to 800° C.; the average particle diameter of the expandable graphite is 5 μm to 150 μm, and the expansion multiple of the expandable graphite is 20 to 500.

3. The halogen-free flame retardant thermoplastic polyurethane elastomer composition according to claim 1, characterized in that the derivatives of melamine are melamine cyanurate.

4. The halogen-free flame-retardant thermoplastic polyurethane elastomer composition according to claim 1, characterized in that the weight-average molecular weight of the thermoplastic polyurethane is from 60,000 to 800,000.

5. The halogen-free flame-retardant thermoplastic polyurethane elastomer composition according to claim 1, characterized in that the weight ratio of the halogen-free flame retardant composition to the thermoplastic polyurethane elastomer in the composition is 0.2-0.8:1.

6. An article comprising the halogen-free flame retardant thermoplastic polyurethane elastomer composition of claim 1.

7. The halogen-free flame-retardant thermoplastic polyurethane elastomer composition according to claim 1, characterized in that n is an integer from 1 to 5; X.sub.1, X.sub.2, X.sub.3 and X.sub.4 are the same or different and are ##STR00010##  ortho-substituted ##STR00011##  or ortho-substituted ##STR00012##

8. The halogen-free flame-retardant thermoplastic polyurethane elastomer composition according to claim 2, characterized in that the initial expansion temperature of the expandable graphite is 210 to 500° C.; and the expansion multiple of the expandable graphite is 30 to 250.

9. The halogen-free flame-retardant thermoplastic polyurethane elastomer composition according to claim 5, characterized in that the weight ratio of the halogen-free flame retardant composition to the thermoplastic polyurethane elastomer in the composition is 0.25-0.45:1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a SEM image of the interior of the carbon layer after combustion of the composition of Example 2;

(2) FIG. 2 is a SEM image of the interior of the carbon layer after combustion of the composition of Example 7.

DETAILED DESCRIPTION

(3) The method provided by the present invention is further described in detail below, but present invention is not limited thereto by any means.

(4) The materials used in the following examples and comparative examples are as follows:

(5) The thermoplastic polyurethane elastomer is produced by Wanhua Chemical Group Co., Ltd., of which:

(6) Wanhua Chemical Wanthane WHT-1565, polyester-based TPU, hardness 65A

(7) Wanhua Chemical Wanthane WHT-1180, polyester-based TPU, hardness 80A

(8) Wanhua Chemical Wanthane WHT-1164, polyester-based TPU, hardness 64D

(9) Wanhua Chemical Wanthane WHT-8175, polyether-based TPU, hardness 75A

(10) Wanhua Chemical Wanthane WHT-8185, polyether-based TPU, hardness 85A

(11) Wanhua Chemical Wanthane WHT-8254, polyether-based TPU, hardness 54D

(12) Wanhua Chemical Wanthane WHT-2190, polycaprolactone-based TPU, hardness 90A

(13) Wanhua Chemical Wanthane WHT-7185, polycarbonate-based TPU, hardness 85A

(14) Wanhua Chemical Wanthane WHT-7190, polycarbonate-based TPU, hardness 90A

(15) Calcium hypophosphite, aluminum hypophosphite: 99 wt % of purity, Hubei Hongjia Chemical Co., Ltd.;

(16) Expandable graphite (hereinafter referred to graphite): Initial expansion temperature 300° C., average particle size of 10 um, Zibo Wuwei Industrial Co., Ltd.;

(17) Melamine cyanurate (MCA): 99.5 wt % of purity, Star-Better (Beijing) Chemical Materials Co., Ltd.;

(18) Ammonium polyphosphate (APP), 99.8 wt % of purity, Kline Chemical;

(19) Pentaerythritol: 99.5 wt % of purity, Yunnan Yuntianhua Co., Ltd.;

(20) Aluminum phosphate: 99.5 wt % of purity, Liaoning Pengda Technology Co., Ltd.;

(21) Magnesium oxide: 99.5 wt % of purity, Yingkou Hengyu Refractories Co., Ltd.;

(22) Resorcinol bis(diphenyl phosphate) (RDP), 99.8 wt % of purity, Zhejiang Wansheng Chemical Co., Ltd.;

(23) Bisphenol A bis(diphenyl phosphate) (BDP), 99.8 wt % of purity, Zhejiang Wansheng Chemical Co., Ltd.;

(24) Meanwhile, the materials used in the following examples and comparative examples that are not listed above, are all of analytical grade.

(25) The test standard of various performance indicators of the flame retardant thermoplastic polyurethane elastomer composition prepared in the Examples and Comparative Examples are as follows:

(26) Hardness test using ASTM D2240 standard;

(27) Tensile strength, elongation test using ASTM D412 standard;

(28) Tear strength test using ASTM D624 standard;

(29) Flame retardant performance test using UL94 standard;

(30) LOI test using ASTM D2863 standard.

(31) In the following Examples and Comparative Examples, the amounts of each formula for preparing the flame retardant thermoplastic polyurethane elastomer composition are all in parts by weight, as shown in Table 1 in detail. In preparation, after pre-mixing the thermoplastic polyurethane elastomer and flame retardant package according to the amount of Table 1, into a closed mixing equipment or an extruder and mixing for 80-120 seconds to obtain the flame retardant thermoplastic polyurethane elastomer composition.

(32) TABLE-US-00001 TABLE 1 Organic phosphorus- based flame Polyurethane/ Hypophosphite/ Phosphate/ retardants/ Others/ in parts by in parts by in parts by in parts by in parts by weight weight weight weight weight Example 1 WHT-1565/100 calcium hypophosphite/31.5 Example 2 WHT-1565/100 aluminum hypophosphite/45 Example 3 WHT-1565/100 APP/45 Example 4 WHT-1565/100 aluminum phosphate/45 Example 5 WHT-1565/100 zinc hypophosphite/65 Example 6 WHT-1565/100 iron hypophosphite/95 Example 7 WHT-1565/100 aluminum graphite/5 hypophosphite/19 Example 8 WHT-1180/100 APP/40 graphite/5; Example 9 WHT-1180/100 aluminum graphite/5; phosphate/40 Example 10 WHT-1180/100 calcium graphite/20 hypophosphite/6 Example 11 WHT-1180/100 aluminum graphite/4.5 hypophosphite/40 Example 12 WHT-1180/100 magnesium graphite/5 hypophosphite/65 Example 13 WHT-1180/100 aluminum RDP/10 graphite/1 hypophosphite/26 Example 14 WHT-1180/100 calcium RDP/35 graphite/2 hypophosphite/6 Example 15 WHT-1180/100 zinc BDP/45 graphite/3 hypophosphite/6 Example 16 WHT-1164/100 aluminum graphite/10 hypophosphite/14 Example 17 WHT-1164/100 aluminum MCA/29 hypophosphite/14 Example 18 WHT-1164/100 aluminum MCA/10 hypophosphite/7 Example 19 WHT-1164/100 calcium hypophosphite/31.5 Example 20 WHT-1164/100 calcium MCA/10 hypophosphite/21.5 Example 21 WHT-1164/100 zinc MCA/50 hypophosphite/25 Example 22 WHT-1164/100 magnesium MCA/65 hypophosphite/10 Example 23 WHT-1164/100 APP/45 Example 24 WHT-1164/100 aluminum phosphate/45 Example 25 WHT-1164/100 APP/40 MCA/5 Example 26 WHT-1164/100 aluminum MCA/5 phosphate/40 Example 27 WHT-8185/100 aluminum graphite/4.5 hypophosphite/9.5 Example 28 WHT-8185/100 aluminum graphite/2; hypophosphite/7 MCA/5 Example 29 WHT-8185/100 calcium graphite/2; hypophosphite/6 MCA/8 Example 30 WHT-8185/100 aluminum graphite/5; hypophosphite/35 MCA/4 Example 31 WHT-8185/100 magnesium graphite/2; hypophosphite/15 MCA/36 Example 32 WHT-8185/100 iron graphite/9; hypophosphite/18 MCA/12 Example 33 WHT-8185/100 aluminum graphite/10; hypophosphite/15 MCA/8 Example 34 WHT-8185/100 zinc graphite/1; hypophosphite/6 MCA/50 Example 35 WHT-8185/100 aluminum graphite/10; phosphate/26 MCA/8 Example 36 WHT-8185/100 APP/20 graphite/1; MCA/50 Example 37 WHT-8254/100 aluminum graphite/3; hypophosphite/18 MCA/10 Example 38 WHT-8254/100 aluminum RDP/4 graphite/2; hypophosphite/10 MCA/7 Example 39 WHT-8254/100 potassium BDP/8 graphite/7; hypophosphite/11 MCA/10 Example 40 WHT-8254/100 sodium RDP/15 graphite/6; hypophosphite/18 MCA/11 Example 41 WHT-8254/100 yttrium BDP/20 graphite/5; hypophosphite/30 MCA/12 Example 42 WHT-8254/100 lanthanum RDP/25 graphite/4; hypophosphite/45 MCA/13 Example 43 WHT-8175/100 APP/20 BDP/10 graphite/3; MCA/10 Example 44 WHT-2185/100 ammonium BDP/12 graphite/3; pyrophosphate/30 MCA/10 Example 45 WHT-7180/100 magnesium RDP/15 graphite/3; phosphate/45 MCA/ Example 46 WHT-7190/100 zinc RDP/20 graphite/6; phosphate/45 MCA/11 Comparative WHT-1164/100 APP/51 pentaeryth- Example 1 ritol/17 Comparative WHT-1164/100 MCA/44 Example 2 Note: the blank space in Table 1 indicates that no such substance is added.

(33) TABLE-US-00002 TABLE 2 Tensile Tear LOI Hardness strength strength Elongation UL94 UL94 Note (%) Notes Example 1 68A 28 MPa 84 N/mm 760% V2.sup.−1.5 mm dropping 28.2 during combustion Example 2 69A 26 MPa 81 N/mm 702% V2.sup.−1.5 mm dropping 29.2 during combustion Example 3 69A 22 MPa 77 N/mm 650% V2.sup.−3.0 mm dropping 28.0 during combustion Example 4 69A 20 MPa 74 N/mm 610% V2.sup.−3.0 mm dropping 27.8 during combustion Example 5 70A 22 MPa 78 N/mm 660% V2.sup.−1.5 mm dropping 30.2 during combustion Example 6 71A 21 MPa 76 N/mm 630% V0.sup.−1.5 mm dropping 31.0 during combustion Example 7 68A 27 MPa 82 N/mm 688% V0.sup.−3.0 mm without 30.4 dropping Example 8 84A 31 MPa 94 N/mm 560% V0.sup.−3.0 mm without 30.4 dropping Example 9 84A 30 MPa 91 N/mm 552% V0.sup.−3.0 mm without 30.2 dropping Example 10 83A 34A 98 N/mm 552% V0.sup.−3.0 mm without 30.2 dropping Example 11 84A 32 MPa 96 N/mm 562% V0.sup.−1.5 mm without 31.2 dropping Example 12 84A 30 MPa 92 N/mm 522% V0.sup.−1.5 mm without 32.6 dropping Example 13 82A 32 MPa 92 N/mm 600% V0.sup.−3.0 mm without 30.4 With dropping excellent Example 14 81A 31 MPa 90 N/mm 620% V0.sup.−3.0 mm without 30.2 processing dropping properties, Example 15 80A 30 MPa 88 N/mm 660% V0.sup.−1.5 mm without 30.2 can be dropping molded by blowing or casting Example 16 65D 36 MPa 114 N/mm 501% V0.sup.−0.75 mm without 31.8 dropping Example 17 65D 35 MPa 112 N/mm 512% V0.sup.−1.5 mm without 31.8 dropping Example 18 64D 38 MPa 120 N/mm 522% V0.sup.−1.5 mm without 31.4 dropping Example 19 64D 37 MPa 116 N/mm 550% V2.sup.−1.5 mm dropping 29.2 during combustion Example 20 65D 35 MPa 105 N/mm 510% V0.sup.−07.5 mm without 33.8 dropping Example 21 66D 28 MPa 99 N/mm 560% V0.sup.−0.75 mm without 34.8 dropping Example 22 66D 28 MPa 98 N/mm 568% V0.sup.−0.75 mm without 35.0 dropping Example 23 65D 30 MPa 101 N/mm 500% V2.sup.−1.5 mm dropping 29.0 during combustion Example 24 65D 30 MPa 101 N/mm 510% V2.sup.−1.5 mm dropping 29.2 during combustion Example 25 65D 31 MPa 102 N/mm 560% V0.sup.−1.5 mm without 30.8 dropping Example 26 65D 30 MPa 101 N/mm 562% V0.sup.−1.5 mm without 31.0 dropping Example 27 86A 30 MPa 85 N/mm 582% V2.sup.−3.0 mm dropping 28.2 during combustion Example 28 87A 28 MPa 80 N/mm 562% V0.sup.−3.0 mm without 30.0 dropping Example 29 86A 30 MPa 85 N/mm 650% V2.sup.−3.0 mm dropping 28.2 during combustion Example 30 87A 25 MPa 85 N/mm 564% V0.sup.−1.5 mm without 31.4 dropping Example 31 87A 22 MPa 81 N/mm 580% V0.sup.−1.5 mm without 31.8 dropping Example 32 87A 25 MPa 85 N/mm 512% V0.sup.−1.5 mm without 31.0 dropping Example 33 87A 24 MPa 88 N/mm 562% V0.sup.−1.5 mm without 31.0 dropping Example 34 87A 22 MPa 80 N/mm 590% V0.sup.−1.5 mm without 32.4 dropping Example 35 87A 24 MPa 85 N/mm 562% V0.sup.−3.0 mm without 30.0 dropping Example 36 87A 26 MPa 90 N/mm 521% V0.sup.−3.0 mm without 31.2 dropping Example 37 65D 34 MPa 102 N/mm 524% V0.sup.−3.0 mm without 20.0 dropping Example 38 65D 32 MPa 100 N/mm 518% V0.sup.−1.5 mm without 31.0 With dropping excellent Example 39 65D 30 MPa 99 N/mm 520% V0.sup.−1.5 mm without 31.2 processing dropping properties, Example 40 65D 31 MPa 98 N/mm 545% V0.sup.−1.5 mm without 32.0 can be dropping molded by Example 41 66D 30 MPa 100 N/mm 523% V0.sup.−1.5 mm without 33.2 blowing or dropping casting Example 42 66D 28 MPa 92 N/mm 554% V0.sup.−1.5 mm without 34.0 dropping Example 43 75A 18 MPa 70 N/mm 745% V0.sup.−3.0 mm without 29.0 dropping Example 44 88A 27 MPa 85 N/mm 573% V0.sup.−3.0 mm without 30.2 dropping Example 45 90A 30 MPa 90 N/mm 545% V0.sup.−3.0 mm without 31.0 dropping Example 46 90A 31 MPa 91 N/mm 533% V0.sup.−3.0 mm without 31.4 dropping Comparative 65D 18 MPa 80 N/mm 451% V0.sup.−3.0 mm dropping 30.4 Example 1 during combustion Comparative 65D 20 MPa 88 N/mm 412% V2.sup.−3.0 mm dropping 28.8 Example 2 during combustion

(34) It can be seen from the above examples that, in the present invention, the addition of inorganic phosphorus-based flame retardant alone can obtain a good retardant effect, especially the addition of inorganic hypophosphite; In addition, adding the inorganic phosphorus-based flame retardant can generate synergistic flame retardant effect with graphite or MCA, the flame retardant effect of adding more organic phosphorus-based flame retardants or melamine cyanurate can be achieved under the condition of smaller additive amount of total flame retardant; in which, under the synergistic effect of graphite and the inorganic phosphorous-based flame retardant, a sufficient carbon-forming effect can be achieved with a small additive amount, thus resulting in a carbon layer structure having a dense surface and an internal porous structure (the internal structure of carbon layers in Example 2 and Example 7 is shown in the electron micrographs of FIG. 1 and FIG. 2, wherein, the carbon layer in FIG. 1 is dense, and is consistent with the dense carbon layer structure phase of its surface; the carbon layer in FIG. 2 is a porous structure, it should be noted that its surface is consistent with the dense carbon layer structure phase of the surface of Example 2, and those skilled in the art can understand that due to the porous carbon layer structure formed by the synergistic effect of expandable graphite and inorganic phosphorous, a smaller additive amount can increase the carbon layer volume significantly), which has excellent flame retardant effect.

(35) In addition, it can be seen from the overall of the examples that after the addition of the expandable graphite, the composition does not drip during the combustion process, and after the organic phosphorus-based flame retardant is added, not only the flame retardant effect is better, but also the processability of the composition is more excellent.