Thermoplastic composition

Abstract

A thermoplastic elastomer composition comprising a blend of (A) thermoplastic materials comprising (A1) a polyamide block copolymer and (A2) one or more thermoplastic organic polymers excluding (A1), with (B) a silicone composition comprising (B1) a silicone base comprising (B1a) a diorganopolysiloxane polymer having a viscosity of at least 1000000 mPa.Math.s at 25° C. and an average of at least 2 alkenyl groups per molecule, (B1b) a reinforcing filler in an amount of from 1 to 50% by weight of polymer (B1a), and (B2) an organohydrido silicone compound which contains an average of at least 2 silicon-bonded hydrogen groups per molecule, (C) a hydrosilylation catalyst, which composition may additionally optionally comprise (D) one or more additives; wherein the weight ratio (A):(B) is in the range 50:50 to 95:5, and wherein component B2 and C being present in an amount sufficient to cure said silicone composition B.

Claims

1. A thermoplastic elastomer composition comprising a blend of (A) thermoplastic materials comprising (A1) a polyamide block copolymer, said polyamide block copolymer comprising hard blocks derived from polyamides and soft blocks derived from polyesters, polyethers, or copolymers of polyesters and polyethers; and (A2) one or more thermoplastic organic polymers that are different from (A1), said thermoplastic organic polymers selected from the group consisting of copolymers with polyurethane blocks and polyether blocks, and copolymers with polyester blocks and polyether blocks; with (B) a silicone composition comprising: (B1) a silicone base comprising (B1a) a diorganopolysiloxane polymer having a viscosity of at least 1,000,000 mPa.Math.s at 25° C. and an average of at least 2 alkenyl groups per molecule, selected from an α, ω-vinyldimethylsiloxy polydimethylsiloxane, an α,ω-vinyldimethylsiloxy copolymer of methylvinylsiloxane and dimethylsiloxane units, and/or an α,ω-trimethylsiloxy copolymer of methylvinylsiloxane and dimethylsiloxane units, and (B1b) a reinforcing filler in an amount of from 1 to 50% by weight of polymer (B1a), and (B2) an organohydrido silicone compound which contains an average of at least 2 silicon-bonded hydrogen groups per molecule; and (C) a hydrosilylation catalyst; which composition may additionally optionally comprise: (D) one or more additives selected from the group consisting of softening mineral oils, plasticizers, mineral fillers that are different from the (B1b) reinforcing filler, viscosity modifiers, stabilizers including UV stabilizers, lubricants, unreactive polydimethylsiloxanes, fire resistant additives, coloring agents, effect pigments, interference pigments, reflective pigments, anti-aging agents, antioxidants, fluidizing agents, anti-abrasion agents, mold-release agents, surfactants, brighteners, fibers, and waxes; wherein the weight ratio (A) : (B) is in the range 50:50 to 95:5, and wherein component B2 and C are present in an amount sufficient to cure said silicone composition B.

2. The thermoplastic elastomer composition according to claim 1 wherein the diorganopolysiloxane polymer (B1a) is a diorganopolysiloxane gum.

3. The thermoplastic elastomer composition according to claim 1 wherein the reinforcing filler (B1b) is silica.

4. The thermoplastic elastomer composition according to claim 3 wherein the silica reinforcing filler (B1b) is present at from 2 to 20% by weight based on the weight of the diorganopolysiloxane polymer (B1a).

5. The thermoplastic elastomer composition according to claim 4 wherein the silica reinforcing filler (B1b) is present at from 6 to 20% by weight.

6. A vulcanized thermoplastic elastomer that is the product of curing the thermoplastic elastomer composition in accordance with claim 1.

7. A part or component for sports equipment, footwear, automotive, appliances, electronics, portable electronic, electrical, communication, and medical applications wherein the part or component comprises the thermoplastic elastomer in accordance with claim 6.

8. A wearable item comprising the thermoplastic elastomer in accordance with claim 6.

9. A process for forming the vulcanized thermoplastic elastomer in accordance with claim 6 comprising mixing (A) the thermoplastic materials, (B) the silicone composition, (C) the hydrosilylation catalyst, and optionally the one or more additives (D).

10. The process according to claim 9 wherein the thermoplastic materials (A), the silicone base (B1), the organohydrido silicone compound (B2) and the hydrosilylation catalyst (C) are contacted at a temperature in the range 100° C. to 250° C.

11. The process according to claim 9 wherein the thermoplastic materials (A), the silicone base (B1), the organohydrido silicone compound (B2) and the hydrosilylation catalyst (C) are blended in an extruder.

12. The process in accordance with claim 9 wherein after forming said thermoplastic elastomer is extruded, co-extruded, laminated, calendered and/or extruded-calendering to form a thermoplastic film or thermoplastic sheet.

13. A method of making a wearable item comprising curing the thermoplastic elastomer composition of claim 1 to form the wearable item, wherein the wearable item is intended to be in contact with the wearer's skin when in use.

14. A method of making a part or component for sports equipment, footwear, automotive, appliances, electronics, portable electronic, electrical, communication, or medical applications, comprising: curing the thermoplastic elastomer composition in accordance with claim 1.

Description

EXAMPLES

(1) The invention is illustrated by the following examples, in which parts and percentages are by weight unless otherwise stated.

(2) The materials used in the Examples were: Si-Rubber 1: Uncatalysed Silicone Rubber Base, comprising a vinyl-terminated diorganopolysilxane gum and silica. The base has a plasticity value of 360 mm/100 measured using a Williams Parallel plate plastimeter in accordance with ASTM D-926-08. Si-Rubber 1 is intended to have a Shore A hardness of 70 upon cure. Si-Rubber 2: Uncatalysed Silicone Rubber base, comprising a vinyl-terminated diorganopolysilxane gum and silica. The base has a plasticity value of 169 mm/100 measured using a Williams Parallel plate plastimeter in accordance with ASTM D-926-08. Si-Rubber 2 is intended to have a shore A hardness of 40 upon cure. A Silicone based catalyst solution containing adequate catalyst concentration able to cure Si Rubber bases above PEBA 3: thermoplastic organic polyether block amide copolymer of 25 shore D PEBA 1 thermoplastic organic polyether block amide copolymer of 41 shore D TPU 1: Aliphatic TPU Desmopan 85085 DP0063 TPU 2: Aromatic TPU Pearlthane 11T85

(3) Thermoplastic elastomers were prepared by mixing of components and vulcanisation was carried out using a twin screw extruder. The processing section was heated in a range from 160° C. up to 240° C. the screw speed was between 150 and 400 rpm. Si-Rubber 1 or 2 was added to an organic thermoplastic pre-blend within the first sections of the extruder, then the organohydridopolysiloxane cross linker and the catalyst, which initiates the vulcanization of the silicone composition within the thermoplastic matrix were added. The proportions of materials are depicted in Table 1 and 3.

(4) Gloss Measurement

(5) Gloss is determined by projecting a beam of light at a fixed intensity and angle onto a surface and measuring the amount of reflected light at an equal but opposite angle.

(6) TABLE-US-00001 TABLE 1 PEBA 1 Ex 1 Ex. 2 Ex. 3 Ex. 4 Si-Rubber 1 with adequate curing 0 20.87 52.8 agent solution and concentration to ensure crosslinking Si Rubber 2 with adequate curing 0 21.19 52.98 agent solution and concentration to ensure crosslinking PEBA 1 100 79.13 78.81 47.82 47.02

(7) Test specimens for mechanical and scratch resistance testing were prepared by injection moulding. Heating temperature for injection moulding was set at 180° C. to 220° C. and mold temperature set at 40° C. The mechanical properties were tested according to international standards as set out in Table 2 below.

(8) TABLE-US-00002 TABLE 2 Unit Standard PEBA 1 Ex 1 Ex. 2 Ex. 3 Ex. 4 Hardness ShoreA ISO 868 93.4 91.8 90.9 87.2 85.5 Tensile strength at MPa ISO 37 8.5 8.6 8.2 7.6 8.5 100% of elongation - transversal- 500 mm/min Tensile strength at MPa ISO 37 8.6 9.8 9.7 9.4 10.6 200% of elongation - transversal- 500 mm/min Tensile strength at MPa ISO 37 9.3 11.7 11.5 11.1 12.4 300% of elongation - transversal- 500 mm/min Tensile strength at MPa ISO 37 43.8 19.5 20.8 15.9 15 break - transversal- 500 mm/min Elongation at % ISO 37 905 528 579 544 455 break - transversal- 500 mm/min Tear strength - N/mm ISO R 128 112.2 98.3 71.8 69.1 Transversal- 34/B/A 500 mm/min Flexural modulus MPa 85 76 63 46 37 Gloss B Internal 34 39 30 13 9

(9) Comparative example (table 2) shows the benefits of present invention in hardness lowering (compared to pure PEBA 1) and moreover flexibility increase.

(10) It can be observe that elastomeric performance in present invention are maintain, with ultimate elongation value over 400%.

(11) It can be observed that present invention is able to manage different properties such as flexibility, hardness, elastic properties and gloss by using various silicone Si Rubber composition with adequate curing agent solution and concentration to ensure crosslinking, and keep using a similar PEBA.

(12) TABLE-US-00003 TABLE 3 PEBA 3 TPU 1 TPU 2 Ex 1 Ex. 2 Ex. 3 Ex. 4 Si-Rubber 1 with 0 26.09 26.09 adequate curing agent solution and concentration to ensure crosslinking Si Rubber 2 with 0 26.49 26.49 adequate curing agent solution and concentration to ensure crosslinking PEBA 3 100 47.02 47.82 47.02 47.82 TPU 1 100 26.49 26.09 TPU 2 100 26.49 26.09

(13) Test specimens for mechanical and scratch resistance testing were prepared by injection moulding. Heating temperature for injection moulding was set at 180° C. to 220° C. and mold temperature set at 40° C. The mechanical properties were tested according to international standards as set out in Table 4 below.

(14) TABLE-US-00004 TABLE 4 Unit Standard PEBA 3 TPU 1 TPU 2 Ex 1 Ex. 2 Ex. 3 Ex. 4 Hardness Shore ISO 868: 80 85.1 85.8 78.7 79.4 76.2 78.7 A 2003(en) Tensile strength MPa ISO 37: 4.1 4.1 5.9 5.1 5.4 4.5 4.6 at 100% of 2011(en) elongation - transversal- 500 mm/min Tensile strength MPa ISO 37: 4.3 5 7.5 7.0 7.1 6.1 5.9 at 200% of 2011(en) elongation - transversal- 500 mm/min Tensile strength MPa ISO 37: 4.9 6.1 10.4 8.9 8.9 7.9 7.7 at 300% of 2011(en) elongation - transversal- 500 mm/min Tensile strength MPa ISO 37: 22.6 22.1 42.3 13 13.7 15.7 17.6 at break - 2011(en) transversal- 500 mm/min Elongation at % ISO 37: 928 887 573 529.1 555.9 544.7 557.5 break - 2011(en) transversal- 500 mm/min Tear strength - N/mm ISO R 87.7 109.9 106.5 73.5 76.9 63.3 65.8 Transversal- 34/B/A 500 mm/min Abrasion Mm3 na 65 46 26 30 27 30 resistance, weight loss, Gloss B na Internal 57 65 70 1.4 1.4 1.4 1.6

(15) Comparative example (table 4), a silicone free elastomer shows a hardness of 80 shore A (PEBA 3), as silicone based elastomer of present invention.

(16) Comparative example in table 4 shows that different composition of present invention helps to increase mechanical performance at 100%, 200% and 300% elongation measured at room temperature comparing to PEBA 3, while maintaining a similar hardness.

(17) Ultimate performance of products based on present invention confirms the elastomeric properties, with ultimate elongation value over 400%.

(18) Another benefits of present invention is the important reduction of surface gloss: addition of a silicone phase in the material brings an intrinsic mat effect while pure CoPA is glossy