CN108587123B

CN108587123B - Dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer and preparation method thereof

Info

Publication number: CN108587123B
Application number: CN201810444492.1A
Authority: CN
Inventors: 徐龙平; 王娟; 雷霆; 谢刚
Original assignee: CHENGDU SILIKE TECHNOLOGY CO LTD
Current assignee: CHENGDU SILIKE TECHNOLOGY CO LTD
Priority date: 2018-05-10
Filing date: 2018-05-10
Publication date: 2021-06-25
Anticipated expiration: 2038-05-10
Also published as: CN108587123A

Abstract

The invention discloses a preparation method of dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer, which comprises the steps of premixing thermoplastic polyurethane, methyl vinyl siloxane, reinforcing filler and chain extender, then carrying out melt extrusion granulation with a catalyst in an internal mixer or a double-screw extruder to prepare polysiloxane master batch, then uniformly mixing the thermoplastic polyurethane, the polysiloxane master batch, a compatilizer and a polymerization inhibitor, and then adding a cross-linking agent and the catalyst for dynamic vulcanization. Because the methyl vinyl siloxane used for preparing the master batch has lower viscosity and is easy to disperse well, and simultaneously can realize chain growth under the action of a catalyst and improve the viscosity and the molecular weight of polysiloxane, the obtained elastomer has better mechanical property and smooth hand feeling, is easy to process, and can be used in high-requirement application fields of buildings, automobile accessories, wires and cables, medical appliances, wearable equipment and the like.

Description

Dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer and preparation method thereof

Technical Field

The invention belongs to the technical field of thermoplastic elastomers and preparation thereof, and particularly relates to a dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer and a preparation method thereof.

Background

Thermoplastic Polyurethane (TPU) is An (AB) n-type block copolymer having a plurality of repeating urethane groups (-NH-COO-) in its molecular chain and comprising flexible segments and rigid segments alternately linked. The rigid chain segment plays the role of an elastic crosslinking point at normal temperature, so that the rigid chain segment becomes an elastic material between common rubber and plastic. The TPU elastomer has wide hardness range, and although the TPU elastomer can be widely applied to the fields of automobile accessories, industrial rubber pipes, gears, shoe materials and the like, in the fields of application of special elastic materials such as wearable equipment accessories, automobile interior decorations, cable sheaths and the like, the TPU elastomer is difficult to meet the requirements of scratch resistance, high and low temperature resistance and the like.

The thermoplastic elastomer prepared by the dynamic vulcanization method not only has the physical and mechanical properties of thermosetting rubber, but also has the flow processability of thermoplastic plastics, and has better processing and using performance compared with the thermoplastic elastomer prepared by simple blending. US patent 6759487B 2 discloses a dynamically vulcanized thermoplastic polyurethane-silicone elastomer and a process for its preparation. Wherein the silica-reinforced silicone elastomer is dispersed in a thermoplastic polyurethane matrix and dynamically vulcanized by a hydrosilylation reaction. Although the thermoplastic elastomer obtained in this way has almost no reduction in physical properties such as hardness and tensile strength when heated for a long time, the silicone rubber has poor compatibility with most thermoplastic resins including TPU and is prone to phase separation due to the non-polarity and low surface energy of the molecular chain of the silicone elastomer. US patent US20170233572 a1 describes a narrower range of formulations than in US 6759487B 2, giving thermoplastic elastomers excellent scratch, abrasion and chemical resistance, but emphasizes the need to select a specific matrix polymer (i.e. TPU or a mixture of TPU and other thermoplastic elastomers). However, the invention still does not improve the compatibility of polysiloxane and organic polymer matrix, and the problems of phase separation or poor interface combination are easy to occur. Chinese patent CN102153853 provides a silicone rubber/polyurethane thermoplastic elastomer, and a certain amount of silicone modified polyurethane is added in the formulation as a compatibilizer, but the problem of poor dispersion still exists because the viscosity of silicone rubber is greatly different from that of polyurethane. Since the above technical solutions all adopt direct addition of silicone rubber as a rubber phase, there are problems as follows: the silicon rubber has high molecular weight, high viscosity and great direct feeding difficulty, and needs special feeding and processing equipment with high investment. Secondly, the silicon rubber has no fluidity like that of thermoplastic resin at high temperature, has large viscosity difference with resin matrix, and is difficult to disperse uniformly, so that the performance of the obtained thermoplastic elastomer can not be ensured.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a novel preparation method of dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer.

It is another object of the present invention to provide a dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer prepared by the above process which meets the requirements of use in some particular fields.

The invention provides a preparation method of a novel dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer, which is characterized by comprising the following process steps and conditions:

(1) 100 parts of thermoplastic polyurethane, 100-200 parts of methyl vinyl siloxane, 50-100 parts of reinforcing filler and 1-10 parts of chain extender are premixed, and then the premixed material is mixed with a catalyst with the content of 2.5 multiplied by 10 in terms of Pt, Pd, Rh, Ru, Ni or Co^-4～1×10^-3Adding the mixture into an internal mixer or a double-screw extruder, and carrying out melt extrusion granulation and cooling at 160-240 ℃ to obtain granular or flaky polysiloxane master batch;

(2) uniformly mixing 100 parts of dried thermoplastic polyurethane, 115-400 parts of polysiloxane master batch, 10-25 parts of compatilizer and 0.1-1.5 parts of polymerization inhibitor, adding 2-9 parts of cross-linking agent, continuously and uniformly mixing at 160-240 ℃, and adding 6.0 multiplied by 10 in terms of Pt, Pd, Rh, Ru, Ni or Co content^-3～1.5×10^-2And (3) adding the catalyst, and carrying out dynamic vulcanization at the temperature of 160-240 ℃ under the shearing action of a mixing device.

The thermoplastic polyurethane in the above method is any one of polyester type thermoplastic polyurethane, polyether type thermoplastic polyurethane or aliphatic type thermoplastic polyurethane.

The methyl vinyl siloxane described in the above method has a viscosity of 10 to 300Pa.s (measured at 25 ℃), and a molar fraction of vinyl groups is 0.26 to 0.80%, preferably 0.35 to 0.55%.

The reinforcing filler in the above method is at least one of silicon dioxide prepared by a gas phase method or/and a precipitation method after being treated by any one of hydroxyl-containing oligosiloxane (hydroxyl silicone oil), silazane or borosiloxane.

The chain extender in the method is any one of hydrogen-containing silicone oil containing at least 2 Si-H bonds, and the hydrogen content is 0.10-0.75 wt%.

The catalyst in the method is Pt, Pd, Rh, Ru, Ni, Co and compounds or complexes thereof, preferably Pt and compounds or complexes thereof, and the Pt content is 500-10000 ppm or a commercially available common specification.

The compatibilizer described in the above method is any one of aminopropyl terminated polysiloxane, amino terminated polysiloxane, hydroxyalkyl terminated polysiloxane, epoxy terminated polysiloxane, polyurethane-siloxane copolymer, aminopropylmethylsiloxane-dimethylsiloxane copolymer, polyether-siloxane copolymer, or polyether-polyamine-siloxane copolymer, or caprolactone-siloxane copolymer.

The cross-linking agent in the method is hydrogen-containing silicone oil containing at least 2 Si-H bonds, and the hydrogen content is 0.36-1.60 wt%.

The polymerization inhibitor in the method is an alkyne-containing compound, and specifically is any one of hexynol, 1-ethynyl-1-cyclohexanol, 3-phenyl-1-butyn-3-ol, phenylacetylene, propiolic alcohol, 2-methyl-3-alkyne-2-ol or 3-methyl-1-alkyne-2-ol.

In addition to the above components, suitable amounts of processing aids may be added, including but not limited to antioxidants, stabilizers, flame retardants, anti-uv agents, light stabilizers, colorants, mineral fillers, and the like, polymer processing aids and auxiliary fillers well known in the art. Except that these processing aids should be added prior to the addition of the catalyst to allow more uniform dispersion in the system or added directly to the final thermoplastic polyurethane/silicone elastomer and mixed uniformly.

In the process, the initial molecular weight and viscosity of the polysiloxane are low, and the polysiloxane is easily and uniformly dispersed in the carrier resin under the shearing action of the screw. Meanwhile, polysiloxane and hydrogen-containing silicone oil are subjected to addition reaction under the action of a catalyst to obtain polysiloxane with further improved molecular weight and viscosity.

The invention provides a dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer which is prepared by dynamically vulcanizing the following components in parts by weight:

thermoplastic polyurethane 100 parts

115-400 parts of polysiloxane master batch

10-25 parts of compatilizer

2-9 parts of cross-linking agent

0.1 to 1.5 portions of polymerization inhibitor

Catalyst 6.0X 10^-3～1.5×10^-2The preparation method comprises the following steps of (1),

wherein the weight portion of the catalyst is calculated by Pt, Pd, Rh, Ru, Ni or Co, the tensile strength of the elastomer is 6.28-12.71MPa, the elongation at break is 505.92-799.40%, the compression deformation at 23 ℃ is 20.7-36.78%, the tearing strength is 21.69-53.3KN/m, and the surface quality is smooth.

Compared with the prior art, the invention has the following positive effects:

1. in the dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer provided by the invention, the polysiloxane component is introduced in the form of polysiloxane master batch, so that the final good dispersion of the polysiloxane component in the thermoplastic polyurethane matrix can be ensured, the problem caused by directly adding high-viscosity polysiloxane in a system is avoided, the operation is simple, and the equipment investment is low.

2. In the preparation process of the polysiloxane master batch, the methyl vinyl siloxane adopted by the dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer provided by the invention has low viscosity, is easy to disperse uniformly in the thermoplastic polyurethane, and can react with the chain extender under the action of the catalyst to realize chain growth to generate polysiloxane with higher molecular weight, so that the mechanical property of the final elastomer can be ensured, and the viscosity and the molecular weight of the final polysiloxane can be controlled by adjusting the molecular weight of the chain extender, thereby obtaining the elastomer with wider application range.

3. The dynamic vulcanization thermoplastic polyurethane/polysiloxane elastomer provided by the invention also introduces the compatilizer into the formula system, and the non-siloxane chain segments in the compatilizer and the active groups on the molecular chain of the thermoplastic polyurethane can form certain hydrogen bonds or other chemical bonds, and the siloxane chain segments can be compatible with the polysiloxane component to play a good compatibilization role, so that the interface combination of the polysiloxane and the thermoplastic polyurethane is improved, the phase separation phenomenon cannot occur, and the dispersion effect of the polysiloxane in the thermoplastic polyurethane matrix is further improved.

4. The dynamic vulcanization thermoplastic polyurethane/polysiloxane elastomer provided by the invention has excellent flow processing performance and demoulding performance, and does not need to add plasticizer or filling oil, so that the problem of small molecule precipitation and stickiness in the long-term use process can be avoided, and compared with the traditional thermoplastic polyurethane, the thermoplastic elastomer has more excellent heat resistance, scratch resistance, wear resistance, compression deformation resistance and smooth hand feeling, and can be used in high-requirement application fields such as buildings, automobile accessories, wires and cables, medical instruments, wearable equipment and the like.

Drawings

FIG. 1 is an electron micrograph of the TPU dynamically vulcanized thermoplastic polyurethane/silicone elastomer etched away prepared in example 4 of the present invention.

FIG. 2 is an electron micrograph of a TPU dynamically vulcanized thermoplastic polyurethane/silicone elastomer etched away prepared according to comparative example 3 of the present invention.

FIG. 3 is an electron micrograph of a TPU dynamically vulcanized thermoplastic polyurethane/silicone elastomer etched away prepared according to comparative example 4 of the present invention.

From a comparison of the above figures, it can be seen that the vulcanized silicone particles prepared in example 4 are uniformly dispersed in the TPU and the interfacial bonding is good. In contrast, in comparative example 3 (FIG. 2), the polysiloxane having a high viscosity was directly added, and the polysiloxane was not uniformly dispersed; comparative example 4 (fig. 3) polysiloxane particles cohered and agglomerated in the TPU matrix and the interfacial bond was poor due to the absence of a compatibilizer added to the formulation.

Detailed Description

The present invention is further illustrated by the following examples, which should not be construed as limiting the scope of the invention. Those skilled in the art may make insubstantial modifications and adaptations to the present invention as described above.

It is to be noted that 1) the parts of the raw materials used in the following examples and comparative examples are all parts by weight; 2) the melt flow rates (MFI) of the thermoplastic elastomers obtained in the following examples and comparative examples were measured according to ISO-1133; tensile properties were tested according to ISO-37; the compression set is tested according to the ISO-815 standard; the tear strength was tested according to ISO-34 standard. 3) The following examples and comparative examples used the following starting materials, respectively:

TPU 1: wanhua cigarette holder

WHT-1485, polyester, Shore hardness 85A;

TPU 2: wanhua cigarette holder

WHT-1570, polyester type, Shore hardness 73A;

TPU 3: wanhua cigarette holder

WHT-8180, polyether type, with a Shore hardness of 80A;

polysiloxane mixture: 65% methylvinylsiloxane (viscosity 30000Pa.s at 25 ℃ C., vinyl content 0.16%) and 35% fumed silica (treated with 15% hydroxysilicone oil);

methylvinylsiloxane 1: viscosity at 25 ℃ is 10Pa.s, and vinyl content is 0.80%;

methylvinylsiloxane 2: viscosity at 25 ℃ is 80Pa.s, and vinyl content is 0.55%;

methylvinylsiloxane 3: viscosity at 25 ℃ is 200Pa.s, and vinyl content is 0.30%;

methylvinylsiloxane 4: viscosity at 25 ℃ is 300Pa.s, and vinyl content is 0.26%;

methylvinylsiloxane 5: viscosity at 25 ℃ is 200Pa.s, and vinyl content is 0.40%;

reinforcing filler 1: 15% hydroxy silicone oil treated fumed silica;

reinforcing filler 2: 20% hydroxy silicone oil treated precipitated silica;

chain extender 1: hydrogen-containing silicone oil having a hydrogen content of 0.75 wt%;

chain extender 2: hydrogen-containing silicone oil having a hydrogen content of 0.36 wt%;

chain extender 3: hydrogen-containing silicone oil having a hydrogen content of 0.10 wt%;

1 part of compatilizer: a polyurethane-siloxane copolymer;

a compatilizer 2: an aminopropyl terminated polysiloxane;

a compatibilizer 3: aminopropyl methylsiloxane-dimethylsiloxane copolymer;

crosslinking agent 1: methyl terminated hydrogen-containing silicone oil having a hydrogen content of 0.36 wt%;

crosslinking agent 2: methyl-terminated hydrogen-containing silicone oil with hydrogen content of 0.80 wt%;

crosslinking agent 3: methyl-terminated hydrogen-containing silicone oil having a hydrogen content of 1.60 wt%;

polymerization inhibitor 1: 1-ethynyl-1-cyclohexanol;

polymerization inhibitor 2: a hexynol;

catalyst 1: chloroplatinic acid-vinyltetramethylsiloxane complex solution (concentration 750ppm in terms of platinum content);

catalyst 2: chloroplatinic acid, isopropanol dilute 300 times;

catalyst 3: chloroplatinic acid-vinyltetramethylsiloxane complex solution (concentration 2000ppm, in terms of platinum content);

catalyst 4: chloroplatinic acid, isopropanol, diluted 100 times.

Example 1

Premixing 100 parts of TPU1, 100 parts of methyl vinyl siloxane 3, 50 parts of reinforcing filler 1 and 1 part of chain extender 2, adding the premixed materials into a double-screw extruder with the length-diameter ratio of 48:1, adding 0.33 part of catalyst 1 from a side feeding port, performing melt extrusion granulation at 190 ℃, and cooling and shaping to obtain granular polysiloxane master batch 1.

Example 2

100 parts of TPU1, 155 parts of methyl vinyl siloxane 3, 50 parts of reinforcing filler 1, 25 parts of reinforcing filler 2 and 6 parts of chain extender 2 are premixed and then added into a double-screw extruder with the length-diameter ratio of 48:1, 0.43 part of catalyst 1 is added from a side feeding port, and the mixture is melted, extruded and granulated at 190 ℃, cooled and shaped to obtain granular polysiloxane master batch 2.

Example 3

Premixing 100 parts of TPU1, 200 parts of methyl vinyl siloxane 5, 60 parts of reinforcing filler 1, 40 parts of reinforcing filler 2 and 10 parts of chain extender 2, adding the premixed materials into a double-screw extruder with the length-diameter ratio of 48:1, adding 0.54 part of catalyst 1 from a side feeding port, carrying out melt extrusion granulation at 190 ℃, and carrying out cooling setting to obtain granular polysiloxane master batch 3.

Example 4

100 parts of TPU2, 150 parts of methylvinylsiloxane 1, 40 parts of reinforcing filler 1, 30 parts of reinforcing filler 1 and 8 parts of chain extender 1 are premixed and then added into a double-screw extruder with the length-diameter ratio of 48:1, 0.4 part of catalyst 2 is added from a side feeding port, and the mixture is melted, extruded and granulated at 190 ℃, cooled and shaped to obtain granular polysiloxane master batch 4.

Example 5

100 parts of TPU2, 150 parts of methyl vinyl siloxane 2, 40 parts of reinforcing filler 1, 30 parts of reinforcing filler 1 and 5 parts of chain extender 3 are added into a double-screw extruder with the length-diameter ratio of 48:1, then 0.4 part of catalyst 2 is added from a side feeding port, and the mixture is melted, extruded and granulated at 180 ℃, cooled and shaped to obtain granular polysiloxane master batch 5.

Example 6

100 parts of TPU3, 150 parts of methylvinylsiloxane 4, 40 parts of reinforcing filler 1, 30 parts of reinforcing filler 1 and 5 parts of chain extender 3 are premixed and then added into a double-screw extruder with the length-diameter ratio of 48:1, 0.4 part of catalyst 2 is added from a side feeding port, and the mixture is melted, extruded and granulated at 180 ℃, cooled and shaped to obtain granular polysiloxane master batch 6.

Example 7

And (2) uniformly mixing 100 parts of dried TPU (thermoplastic polyurethane) 1, 200 parts of polysiloxane master batch 1, 15 parts of compatilizer 1 and 0.9 part of polymerization inhibitor 1 in a mixer of a torque rheometer, adding 4.5 parts of cross-linking agent 2, continuously uniformly mixing at 180 ℃ until the torque is balanced, adding 0.48 part of catalyst 3, and dynamically vulcanizing at 180 ℃ and 60rpm of rotor speed under the shearing action of a mixing device.

The resulting dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomers were pressed into tablets on a flat vulcanization press at 200 ℃ for performance testing, and the results are shown in Table 1.

Example 8

And (2) uniformly mixing 100 parts of dried TPU (thermoplastic polyurethane) 1, 200 parts of polysiloxane master batch 2, 15 parts of compatilizer 1 and 0.9 part of polymerization inhibitor 1 in a mixer of a torque rheometer, adding 4.5 parts of cross-linking agent 2, continuously uniformly mixing at 180 ℃ until the torque is balanced, adding 0.48 part of catalyst 3, and dynamically vulcanizing at 180 ℃ and 60rpm of rotor speed under the shearing action of a mixing device.

Example 9

And (2) uniformly mixing 100 parts of dried TPU (thermoplastic polyurethane) 1, 115 parts of polysiloxane master batch 3, 11.5 parts of compatilizer 1 and 0.7 part of polymerization inhibitor 1 in a mixer of a torque rheometer, adding 3 parts of cross-linking agent 2, continuously uniformly mixing at 180 ℃ until the torque is balanced, adding 0.35 part of catalyst 3, and dynamically vulcanizing at 180 ℃ and 60rpm of rotor speed under the shearing action of a mixing device.

Example 10

After 100 parts of dried TPU1, 200 parts of polysiloxane master batch 3, 15 parts of compatilizer 1 and 0.9 part of polymerization inhibitor 1 are uniformly mixed in a mixer of a torque rheometer, 4.5 parts of cross-linking agent 2 is added (0.48 part of catalyst 3 is added after the mixture is continuously uniformly mixed at 180 ℃ until the torque is balanced, and dynamic vulcanization is carried out under the shearing action of a mixing device at the temperature of 180 ℃ and the rotating speed of a rotor of 60 rpm.

Example 11

And (2) uniformly mixing 100 parts of dried TPU (thermoplastic polyurethane) 1, 400 parts of polysiloxane master batch 3, 25 parts of compatilizer 1 and 1.2 parts of polymerization inhibitor 1 in a mixer of a torque rheometer, adding 9 parts of cross-linking agent 2, continuously uniformly mixing at 180 ℃ until the torque is balanced, adding 0.8 part of catalyst 3, and dynamically vulcanizing at 180 ℃ and 60rpm of rotor speed under the shearing action of a mixing device.

Example 12

After 100 parts of dried TPU2, 250 parts of polysiloxane master batch 4, 10 parts of compatilizer 3 and 0.1 part of polymerization inhibitor 2 are uniformly mixed, the mixture is added with a length-diameter ratio of 52: 1, 7 parts of cross-linking agent 1 is added from the second section of the extruder and is melted and extruded at 170 ℃, and 0.6 part of catalyst 3 is added from the fourth section of the extruder and is dynamically vulcanized and extruded at 170 ℃.

The resulting dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomers were pressed into tablets on a flat vulcanization press at 180 ℃ for performance testing, and the results are shown in Table 2.

Example 13

After 100 parts of dried TPU2, 250 parts of polysiloxane master batch 5, 14 parts of compatilizer 2 and 0.3 part of polymerization inhibitor 2 are uniformly mixed, the mixture is added with a length-diameter ratio of 52: 1, 7 parts of cross-linking agent 1 is added from the second section of the extruder and is melted and extruded at 170 ℃, and 0.6 part of catalyst 3 is added from the fourth section of the extruder and is dynamically vulcanized and extruded at 170 ℃.

Example 14

After 100 parts of dried TPU2 and 400 parts of polysiloxane master batch 5 are uniformly mixed with 25 parts of compatilizer 2 and 1.5 parts of polymerization inhibitor 2, the mixture is added with a length-diameter ratio of 52: 1, 2 parts of cross-linking agent 3 is added from the second section of the extruder and is melted and extruded at 170 ℃, and 0.9 part of catalyst 4 is added from the fourth section of the extruder and is dynamically vulcanized and extruded at 170 ℃.

Example 15

After uniformly mixing 100 parts of dried TPU3, 250 parts of polysiloxane master batch 6, 14 parts of compatilizer 3 and 0.6 part of polymerization inhibitor 2, adding the mixture with the length-diameter ratio of 52: 1, 7 parts of cross-linking agent 1 is added from the second section of the extruder and is melted and extruded at 170 ℃, and 0.6 part of catalyst 3 is added from the fourth section of the extruder and is dynamically vulcanized and extruded at 170 ℃.

Example 16

After uniformly mixing 100 parts of dried TPU3, 400 parts of polysiloxane master batch 6, 20 parts of compatilizer 2 and 1.5 parts of polymerization inhibitor 2, adding the mixture with the length-diameter ratio of 52: 1, 2 parts of cross-linking agent 3 is added from the second section of the extruder and is melted and extruded at 170 ℃, and 0.9 part of catalyst 4 is added from the fourth section of the extruder and is dynamically vulcanized and extruded at 170 ℃.

Comparative example 1

And uniformly mixing 100 parts of dried TPU1, 115 parts of polysiloxane master batch 3 and 11.5 parts of compatilizer 1 in a mixer of a torque rheometer, and continuously uniformly mixing at 180 ℃ and 60rpm of rotor speed until the torque is balanced.

The resulting elastomer mixtures were pressed into tablets on a flat vulcanization press at 200 ℃ for property testing, the results of which are shown in Table 3.

Comparative example 2

And (3) uniformly mixing 100 parts of dried TPU1, 200 parts of polysiloxane master batch 3 and 15 parts of compatilizer 1 in a mixer of a torque rheometer, and then continuously uniformly mixing at the temperature of 180 ℃ and the rotating speed of a rotor of 60rpm until the torque is balanced.

Comparative example 3

And (2) uniformly mixing 100 parts of dried TPU1, 100 parts of polysiloxane mixture and 10 parts of compatilizer 1 in a mixer of a torque rheometer, adding 4.5 parts of cross-linking agent 2 at the temperature of 180 ℃, continuously uniformly mixing at the rotor speed of 60rpm until the torque is balanced, adding 0.48 part of catalyst 3, and dynamically vulcanizing at the temperature of 180 ℃ and at the rotor speed of 60rpm under the shearing action of a mixing device.

The resulting dynamically vulcanized elastomer blends were pressed into tablets on a press vulcanizer at 200 ℃ for performance testing, and the results are shown in Table 3.

Comparative example 4

And (2) uniformly mixing 100 parts of dried TPU1 and 200 parts of polysiloxane master batch 3 in a mixer of a torque rheometer, adding 4.5 parts of cross-linking agent 2 at the temperature of 180 ℃, continuously uniformly mixing at the rotor speed of 60rpm until the torque is balanced, adding 0.48 part of catalyst 3, and dynamically vulcanizing at the temperature of 180 ℃ and the rotor speed of 60rpm under the shearing action of a mixing device.

Since comparative examples 1, 2 produced directly simple blends of TPU and polysiloxane, the mechanical properties were much poorer than those of the corresponding thermoplastic elastomers obtained by dynamic vulcanization of examples 9, 10 (see tables 1, 3). In contrast, comparative example 3, in which a high viscosity silicone mixture was directly added, even though the sample was prepared by dynamic vulcanization, the high viscosity silicone itself was incompatible with the TPU, which resulted in uneven silicone dispersion (see FIG. 2), and uneven vulcanization, which resulted in rough sample surfaces and poor properties. Comparative example 4 because no compatibilizer was added to the formulation, not only was the polysiloxane dispersed very unevenly in the TPU, but also it was not evenly after vulcanization, as reflected in the electron micrograph of fig. 3, i.e. the polysiloxane particles adhered and agglomerated in the TPU matrix and the interfacial bonding was also not good.

TABLE 1

TABLE 2

TABLE 3

Claims

1. A preparation method of dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer is characterized in that the method comprises the following process steps and conditions:

(1) 100 parts of thermoplastic polyurethane, 100-200 parts of methyl vinyl siloxane, 50-100 parts of reinforcing filler and 1-10 parts of chain extender are premixed, and then the premixed material is mixed with a catalyst with the content of 2.5 multiplied by 10 in terms of Pt, Pd, Rh, Ru, Ni or Co^-4~1×10^-3Adding the mixture into an internal mixer or a double-screw extruder, and carrying out melt extrusion granulation and cooling at 160-240 ℃ to obtain granular or flaky polysiloxane master batch;

(2) uniformly mixing 100 parts of dried thermoplastic polyurethane, 115-400 parts of polysiloxane master batch, 10-25 parts of compatilizer and 0.1-1.5 parts of polymerization inhibitor, adding 2-9 parts of cross-linking agent, continuously and uniformly mixing at 160-240 ℃, and adding 6.0 multiplied by 10 in terms of content of Pt, Pd, Rh, Ru, Ni or Co^-3~1.5×10^-2The catalyst is added and dynamically vulcanized under the shearing action of a mixing device at the temperature of 160-240 ℃,

wherein the viscosity of the methyl vinyl siloxane is 10-300 Pa.s, and the mole fraction of vinyl is 0.26-0.80%; the compatilizer is any one of aminopropyl terminated polysiloxane, amino terminated polysiloxane, hydroxyalkyl terminated polysiloxane, epoxy terminated polysiloxane, polyurethane-siloxane copolymer, aminopropyl methyl siloxane-dimethyl siloxane copolymer, polyether-siloxane copolymer or polyether-polyamine-siloxane copolymer or caprolactone-siloxane copolymer.

2. The process for the preparation of dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer according to claim 1, wherein said thermoplastic polyurethane is any one of polyester type thermoplastic polyurethane, polyether type thermoplastic polyurethane or aliphatic thermoplastic polyurethane.

3. The process for the preparation of dynamically vulcanized thermoplastic polyurethane/silicone elastomers according to claim 1 or 2, wherein the reinforcing filler is at least one of a fumed silica or/and a precipitated silica treated with any one of a hydroxyl-containing oligosiloxane, silazane or borosiloxane.

4. The process for preparing a dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer according to claim 1 or 2, wherein the chain extender is any one of hydrogen-containing silicone oils having at least 2 Si-H bonds, and the hydrogen content is 0.10 to 0.75 wt%.

5. The process for preparing a dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer according to claim 3, wherein said chain extender is any one of hydrogen-containing silicone oils having at least 2 Si-H bonds, and the hydrogen content is 0.10 to 0.75 wt.%.

6. The process for the preparation of dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomers according to claim 1 or 2, wherein said crosslinking agent is a hydrogen-containing silicone oil having at least 2 Si-H bonds and having a hydrogen content of 0.36 to 1.60% by weight.

7. The process for preparing a dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomer according to claim 5, wherein said crosslinking agent is a hydrogen-containing silicone oil having at least 2 Si-H bonds and having a hydrogen content of 0.36 to 1.60% by weight.

8. Process for the preparation of dynamically vulcanised thermoplastic polyurethane/silicone elastomers as claimed in claim 1 or 2, characterized in that the polymerization inhibitor in the process is any one of hexynol, 1-ethynyl-1-cyclohexanol, 3-phenyl-1-butyn-3-ol, phenylacetylene, propynol, 2-methyl-3-yn-2-ol or 3-methyl-1-yn-2-ol.

9. The process for the preparation of dynamically vulcanized thermoplastic polyurethane/polysiloxane elastomers according to claim 7, wherein said polymerization inhibitor is any one of hexynol, 1-ethynyl-1-cyclohexanol, 3-phenyl-1-butyn-3-ol, phenylacetylene, propynol, 2-methyl-3-yn-2-ol or 3-methyl-1-yn-2-ol.

10. A dynamically vulcanized thermoplastic polyurethane/silicone elastomer prepared by the process of claim 1, which elastomer is prepared by dynamic vulcanization of the following components in parts by weight:

thermoplastic polyurethane 100 parts

115-400 parts of polysiloxane master batch

10-25 parts of compatilizer

2-9 parts of cross-linking agent

0.1 to 1.5 portions of polymerization inhibitor

Catalyst 6.0X 10^-3~1.5×10^-2The preparation method comprises the following steps of (1),