An adaptive flexible TPE clamp material and a preparation method thereof

Abstract

The application discloses a self-adaptive flexible TPE clamp material, which comprises a TPE resin and a shape memory compound compounded with the TPE resin, wherein the TPE resin comprises the following components: 50-70 wt% SEBS matrix, 10-20 wt% C9 petroleum resin, 10-20 wt% plasticizer and 5-15 wt% functional additives; and raw materials of the shape memory compound comprise the following components: 50-70 wt% polycaprolactone diol, 15-35 wt% 4,4'-diphenyl methane diisocyanate, 5-15 wt% chain extender and 2-6 wt% nano graphene oxide. The TPE clamp material is prepared by compounding the TPE resin and the shape memory compound with the shape memory function, so that the clamp can recover the original shape more quickly to adapt to objects with different sizes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermoplastic elastomer materials, and in particular to a self-adaptive flexible TPE clamp material and a preparation method thereof. BACKGROUND

[0002] TPE (thermoplastic elastomer) is a kind of polymer material with rubber elasticity and plastic processing performance. It presents rubber characteristics at room temperature and can be molded at high temperature without vulcanization. It can be processed by injection molding, extrusion and other thermoplastic processes. Its molecular structure is composed of "hard segment" (resin phase) and "soft segment" (rubber phase). The hard segment forms microzones through physical crosslinking, and the soft segment provides elasticity.

[0003] In recent years, TPE materials have rapidly replaced traditional rubber and some plastics in the fields of automobiles, medical treatment, electronics, etc. due to their unique "elasticity + plasticity" advantages. For example, in the automotive industry, TPE materials are mainly used in the preparation of instrument panel soft touch layer, seat support pad, etc.; in the medical field, TPE materials are mainly used in the preparation of infusion tubes, sealing pads, etc.; in the field of wire and cable, TPE materials are mainly used in the preparation of insulation layer and sheath; in the field of building industry, TPE materials are mainly used in the preparation of waterproof paint, sealing material, etc.; in the consumer goods industry, TPE materials are mainly used in the preparation of mobile phone cases, sports equipment handles, toys and clamps, etc.

[0004] With the progress of science and technology, the performance of TPE materials is also continuously improving, but there are still some deficiencies. For example, the rigidity-flexibility switching of traditional TPE clamp materials (such as SEBS-based materials) mainly depends on external heating / cooling, which has a slow response speed; the resilience recovery force is single, which cannot adapt to the complex curved surface clamping demand; or, plastic deformation easily occurs after long-term use, which affects the clamping stability of the consumer, thereby affecting the use of the consumer. SUMMARY

[0005]

Problems to be solved

[0006] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present application is to provide a flexible clamp material with shape self-adaptive ability and a preparation method thereof, which has better elasticity and resilience recovery force and can quickly respond, especially suitable for robot clamping, precision instrument clamping, instrument clamping, instrument fixing or positioning, etc., and more in line with user needs.

[0007]

Means for solving the problem

[0008] An adaptive flexible TPE clamp material, comprising a TPE resin and a shape memory compound compounded with the TPE resin, the TPE resin comprising the following components: 50-70 wt% SEBS matrix, 10-20 wt% C9 petroleum resin, 10-20 wt% plasticizer and 5-15 wt% functional additives; the raw material of the shape memory compound comprising the following components: 50-70 wt% polycaprolactone diol (PCL-diol), 15-35 wt% 4,4'-diphenyl methane diisocyanate (MDI), 5-15 wt% chain extender and 2-6 wt% nano-oxidized graphene.

[0009] The technical solution is mainly to prepare a TPE clamp material by compounding a TPE resin and a shape memory compound with shape memory function, so that the clamp can quickly restore the original shape to adapt to objects of different sizes.

[0010] Preferably, the mass ratio of the TPE resin to the shape memory compound is 2-5:1.

[0011] Preferably, the nano-oxidized graphene is loaded on a temperature-sensitive material, and the preparation method of the loading comprises the following steps:

[0012] (1) mixing the temperature-sensitive material with the nano-oxidized graphene for preliminary adsorption; wherein the temperature-sensitive material and the nano-oxidized graphene can be preliminarily adsorbed through π-π conjugation or hydrogen bonding;

[0013] (2) adding a crosslinking agent or an initiator to perform in-situ polymerization at 50-70°C to form a chemical bonding network;

[0014] (3) removing unreacted monomers or impurities by centrifugation or dialysis.

[0015] The compounding of the nano-oxidized graphene and the temperature-sensitive material can form a smart response type composite material, especially a temperature-sensitive response, thereby improving the mechanical strength, response speed and functional diversity of the shape memory compound.

[0016] Preferably, the temperature-sensitive material is poly-N-isopropyl acrylamide (PNIPAM) or PBI-PNIPAM, which is purchased from Shenzhen Lijing Biochemical Technology Co., Ltd.

[0017] Preferably, the shape memory compound is prepared by the following steps:

[0018] A, prepolymer preparation: polycaprolactone diol reacts with 4,4'-diphenyl methane diisocyanate to obtain a prepolymer;

[0019] B, chain extension and functionalization: adding a chain extender and a catalyst to the prepolymer for chain extension; then adding dispersed nano-oxidized graphene for mixing and dispersion, and the shape memory compound is obtained.

[0020] Preferably, the specific step of step A is: the polycaprolactone diol is pre-dehydrated in a 100-120℃ environment, and then reacted with 4,4'-diphenyl methane diisocyanate in a 70-90℃ nitrogen environment to obtain a prepolymer.

[0021] Preferably, in step B, the temperature condition of chain extension is 65-85℃; the chain extender is an aliphatic diol; and the mass ratio of the catalyst is 0.5-1.5wt%.

[0022] Further, the chain extender is preferably 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol or 1,6-hexanediol; the catalyst is dibutyltin dilaurate; and the nanometer graphene oxide is dispersed by pre-adding dimethylformamide (DMF) and ultrasonic treatment.

[0023] In the technical solution, the SEBS matrix serves as a basic elastomer, having the effects of high elasticity and aging resistance. The addition of the plasticizer is conducive to improving the temperature sensitivity of the TPE resin, producing the effects of low-temperature plasticization and high-temperature softening, so that the fixture is more easily attached to an object.

[0024] The C9 petroleum resin added in the TPE resin of the technical solution has good compatibility with the SEBS matrix, forms physical crosslinking points through molecular chain entanglement, and significantly improves the cohesive strength, wear resistance and flexibility; in addition, the C9 petroleum resin forms a uniform dispersion system with the TPE molecular chain in a molten state, which can reduce the melt viscosity, shorten the injection molding cycle and reduce energy consumption.

[0025] Preferably, the plasticizer is paraffin oil or naphthenic oil. Further preferably, the paraffin oil is paraffin oil 150N or 500N oil; and the naphthenic oil is KN4006 or KN4010.

[0026] Preferably, the functional additive includes one or more of nanosilica, an antioxidant, a photoinitiator, a UV stabilizer and a conductive filler.

[0027] Specifically, the nanosilica can enhance rigidity and improve the wear resistance and dispersibility of the TPE fixture; the antioxidant, the photoinitiator, the UV stabilizer and the like are conducive to avoiding thermal oxidative degradation of the TPE fixture, thereby improving the outdoor durability of the TPE fixture. The addition of the conductive filler is conducive to activating the shape memory of the TPE fixture through electrothermal response, achieving dynamic adjustment.

[0028] Preferably, the conductive filler includes one or more of conductive carbon black, graphene and carbon nanotubes.

[0029] Further, the functional additives include 0.5-5 wt% nano-silica, 0.5-1.5 wt% antioxidant, 1-2 wt% photoinitiator, 0.5-2 wt% UV stabilizer, and 0.5-5 wt% conductive filler.

[0030] A preparation method of the TPE clamp material as described above, the TPE clamp material being prepared by the following steps:

[0031] S1: premixing: the SEBS base, C9 petroleum resin, and plasticizer are premixed and then added to the main feeding port of the extruder to obtain a premix;

[0032] S2: blending: the shape memory compound and the functional additives are added to the side feeding port of the extruder and then melt-blended and extruded with the premix;

[0033] S3: molding: an injection molding process is adopted to inject into a mold and cool and demold.

[0034] Preferably, in step S1, the SEBS base, C9 petroleum resin, and plasticizer are premixed by a high-speed blender at a speed of 8000-12000 rpm for 3-5 minutes; in step S2, the shape memory compound and the functional additives are mixed and then melt-blended with the premix at a temperature of 180-220℃; in step S3, the mold temperature in the injection molding process is 40-60℃, and the injection pressure is 80-100 MPa.

[0035] Preferably, in step S3, after the mixture is injected into the mold, it is irradiated with ultraviolet light at an intensity of 50-100 mW / cm 2 for 0.5-1.5 min to initiate crosslinking reaction and form a three-dimensional network.

[0036] A clamp comprising the TPE clamp material as described above.

[0037]

Effects of the Invention

[0038] The TPE clamp material of the present application mainly adds a shape memory compound, which forms a strong interfacial bond with the TPE resin through hydrogen bonds / van der Waals forces, effectively transmits external stress during deformation, improves the reliability and response speed of the shape memory effect, and improves the mechanical properties and permanent deformation resistance of the TPE clamp material.

[0039] The shape memory compound of the present application can quickly trigger phase change and realize shape recovery under specific electrothermal stimulation by introducing nano-oxidized graphene, breaking through the spatial limitations of traditional thermal response, and thus endowing the TPE clamp with rapid, precise, and controllable recovery capability. DETAILED DESCRIPTION

[0040] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined object, the specific embodiments, structures, features and effects according to the present application are described in detail as follows in combination with the embodiments.

[0041] Embodiment 1

[0042] An adaptive flexible TPE clamp material, comprising a TPE resin and a shape memory compound compounded with the TPE resin, wherein the mass ratio of the TPE resin and the shape memory compound is 4:1. Wherein 100 parts by weight of the TPE resin comprises the following components and parts by weight: SEBS matrix 64 parts, C9 petroleum resin 15 parts, paraffin oil 150N 15 parts, nano-silicon dioxide 3 parts, conductive carbon black 3 parts.

[0043] Specifically, 100 parts by weight of the raw materials of the shape memory compound comprises the following components and parts by weight: polycaprolactone diol 60 parts, 4, 4'-diphenyl methane diisocyanate 25 parts, 1, 4-butanediol 10 parts, nano-graphene oxide 4 parts and catalyst 1 part. The shape memory compound is prepared by the following steps:

[0044] A, prepolymer preparation: polycaprolactone diol is dehydrated at 110℃ for 2 hours, and then reacted with 4, 4'-diphenyl methane diisocyanate at 80℃ under nitrogen protection for 3 hours (NCO / OH molar ratio = 2:1), to obtain a prepolymer;

[0045] B, chain extension and functionalization: after adding 1, 4-butanediol and catalyst dibutyltin dilaurate to the prepolymer, chain extension is carried out at 75℃ for 1 hour; then nano-graphene oxide after dispersion is added and mixed, and stirred and dispersed for 2 hours, to obtain the shape memory compound.

[0046] Wherein, the nano-graphene oxide is loaded on a temperature-sensitive material, comprising the following steps:

[0047] (1) mixing the temperature-sensitive material poly-N-isopropyl acrylamide with nano-graphene oxide, and preliminarily adsorbing by π-π conjugation or hydrogen bonding;

[0048] (2) adding a crosslinking agent glutaraldehyde, and carrying out in-situ polymerization at 60℃ to form a chemical bonding network;

[0049] (3) after removing unreacted monomers or impurities by centrifugation or dialysis, collecting the compound.

[0050] Wherein, the specific steps of dispersing the nano-graphene oxide are: adding the nano-graphene oxide into dimethylformamide and ultrasonic treatment for 30 minutes.

[0051] The TPE clamp material is prepared by the following steps:

[0052] S1: premixing: SEBS base, C9 petroleum resin and paraffin oil 150N are premixed by high-speed mixer, wherein the rotating speed of the high-speed mixer is 10000 rpm, the premixing time is 3-5 minutes; then, the premixing material is added into the main feeding port of the twin-screw extruder;

[0053] S2: blending: the shape memory compound prepared above is added into the side feeding port of the twin-screw extruder, then nano-silicon dioxide and conductive carbon black are added, and after mixing, the premixing material in the main feeding port is melt-blended at 180℃ and then extruded;

[0054] S3: molding: injection molding process is adopted, the mold is injected, the mold temperature is 50℃, the injection pressure is 100 MPa, and the mold is cooled and demolded.

[0055] Example 2

[0056] The difference between this embodiment and Example 1 is that 100 parts by weight of the shape memory compound comprises the following components and parts by weight: polycaprolactone diol 50 parts, 4, 4'-diphenyl methane diisocyanate 35 parts, 1, 4-butanediol 10 parts, nano graphene oxide 3.5 parts and catalyst 1.5 parts.

[0057] Example 3

[0058] The difference between this embodiment and Example 1 is that 100 parts by weight of the shape memory compound comprises the following components and parts by weight: polycaprolactone diol 70 parts, 4, 4'-diphenyl methane diisocyanate 15 parts, 1, 4-butanediol 12.5 parts, nano graphene oxide 2.5 parts and catalyst 0.5 parts.

[0059] Example 4

[0060] The difference between this embodiment and Example 1 is that 100 parts by weight of the TPE resin comprises the following components and parts by weight: SEBS base 53 parts, C9 petroleum resin 20 parts, naphthenic oil KN4006 20 parts, nano-silicon dioxide 3 parts, graphene 4 parts.

[0061] Example 5

[0062] The difference between this embodiment and Example 1 is that 100 parts by weight of the TPE resin comprises the following components and parts by weight: SEBS base 70 parts, C9 petroleum resin 10 parts, paraffin oil 500N oil 10 parts, nano-silicon dioxide 3 parts, antioxidant (1010) 3 parts, photoinitiator benzophenone 2 parts, graphene 2 parts.

[0063] Example 6

[0064] The difference between this embodiment and Example 1 is that in step S2 of the preparation step of the TPE clamp material, no shape memory compound is added, but after step S3, a shape memory compound is coated on the surface of the prepared TPE clamp material with a coating thickness of 200-220 μm, and then the TPE compound is placed in an oven at 80°C for curing for 6 hours to obtain the required TPE clamp material.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is that the TPE clamp material only has TPE resin without shape memory compound.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that in the preparation of the shape memory compound of the TPE clamp material, the nano-oxidized graphene is replaced by graphene.

[0069] Comparative Example 3

[0070] The difference between this comparative example and Example 1 is that the nano-oxidized graphene added in the shape memory compound of the TPE clamp material is not pre-loaded on the temperature-sensitive material.

[0071] Comparative Example 4

[0072] The difference between this comparative example and Example 1 is that in the preparation of the TPE clamp material, the C9 petroleum resin is replaced by white mineral oil.

[0073] The above obtained clamps are numbered, wherein the clamps of Examples 1-6 are numbered 1-6, and the clamps of Comparative Examples 1-4 are numbered 7-10.

[0074] Shape recovery performance test

[0075] Test method: the clamps of the examples and comparative examples are heated to 60°C by power supply, an external force is applied to bend them to 90° and fixed; after cooling to 25°C by power off, the external force is removed, and the initial deformation angle is recorded; after heating to 60°C again, the angle after recovery is measured, and the shape recovery rate is calculated. The shape recovery rate is the recovery angle / initial deformation angle x 100%.

[0076]

Evaluation

[0077] 1. Mechanical strength

[0078] Test method: 1. According to ASTM D412 standard, the tensile strength and elongation at break of the clamps of the examples and comparative examples are measured, wherein the tensile strength is the stress (MPa) when the clamp breaks, and the elongation at break is the elongation rate (%) when the clamp breaks, wherein the elongation at break = (L tL0 / L0x100%, wherein L0 is the length measured before the tensile test, and L is the length measured after the tensile test. t L0 is the length measured before the tensile test, and L is the length measured after the tensile test.

[0079] 2. Anti-deformation

[0080] After measuring the original height of the clamps of the examples and the comparative examples, the clamps were placed in a compression device, and the clamps were compressed by 25% at 70°C for 24 hours. Then, the height of the clamps in the compressed state was measured. After removing the load, the height of the clamps after recovery was measured after 30 minutes of standing. The compression permanent deformation rate (%) was calculated.

[0081] Compression permanent deformation rate = (H0-H1) / (H0-H s ) x 100%, wherein H0 is the original height, H1 is the height after recovery, and H is the height in the compressed state. s

[0082] The test results are shown in the following table

[0083]

[0084] From the above test results, it can be seen that the TPE clamps prepared in the present application have good test results in shape recovery rate, tensile strength, elongation at break and compression permanent deformation rate, and have better performance than the TPE clamps of the comparative examples.

[0085] The above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions described in the foregoing examples can still be modified, or some or all of the technical features can be replaced by equivalents. Such modifications or replacements do not change the essence of the corresponding technical solutions, and they should be covered in the scope of the claims and the description of the present application. In particular, each technical feature mentioned in each example can be combined in any manner without structural conflict. The present application is not limited to the specific examples disclosed herein, but includes all technical solutions falling within the scope of the claims.​

Claims

1. A self-adapting flexible TPE clamp material, characterized in that, A TPE resin and a shape memory composite compounded with the TPE resin; wherein the TPE resin comprises the following components: 50-70wt% SEBS base, 10-20wt% C9 petroleum resin, 10-20wt% plasticizer and 5-15wt% functional additives; the raw materials of the shape memory composite comprise the following components: 50-70wt% polycaprolactone diol, 15-35wt% 4,4'-diphenyl methane diisocyanate, 5-15wt% chain extender and 2-6wt% nano graphene oxide; The nano graphene oxide is loaded on a temperature-sensitive material, and a preparation method of the loaded material comprises the following steps: (1) mixing the temperature-sensitive material with the nano graphene oxide for preliminary adsorption; (2) adding a crosslinking agent or an initiator to perform in-situ polymerization at 50-70°C to form a chemical bonding network; (3) removing unreacted monomers or impurities by centrifugation or dialysis; The shape memory composite is prepared by the following steps: Prepolymer preparation: polycaprolactone diol is reacted with 4,4'-diphenyl methane diisocyanate to obtain a prepolymer; Chain extension and functionalization: the prepolymer is added with a chain extender and a catalyst for chain extension, and then the dispersed nano graphene oxide is mixed and dispersed to obtain the product.

2. The TPE clamp material of claim 1, wherein, The specific steps of step A are: the polycaprolactone diol is pre-dehydrated in a vacuum environment at 100-120°C, and then reacted with 4,4'-diphenyl methane diisocyanate in a nitrogen environment at 70-90°C to obtain a prepolymer; in step B, the temperature condition for chain extension is 65-85°C; the chain extender is an aliphatic diol, and the mass ratio of the catalyst is 0.5-1.5wt%.

3. The TPE clamp material of claim 2, wherein, The chain extender is 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol or 1,6-hexanediol; the catalyst is dibutyltin dilaurate; and the nano graphene oxide is dispersed by pre-adding dimethylformamide (DMF) for ultrasonic treatment.

4. The TPE clamp material of claim 1, wherein, The plasticizer is paraffin oil or naphthenic oil.

5. The TPE clamp material of claim 1, wherein, The functional additives include one or more of nano silicon dioxide, an antioxidant, a photoinitiator, a UV stabilizer and a conductive filler.

6. A method of producing a TPE clamp material according to any one of claims 1 to 5, characterized in that, The TPE clamp material is prepared by the following steps: S1: premixing: the SEBS base, the C9 petroleum resin and the plasticizer are premixed and then added to the main feeding port of an extruder to obtain a premix; S2: blending: the shape memory composite and the functional additives are added to the side feeding port of the extruder, and then melt blended and extruded with the premix; S3: molding: an injection molding process is adopted to inject into a mold and then cool and demold.

7. The preparation method according to claim 6, characterized in that, In step S1, the SEBS base, the C9 petroleum resin and the plasticizer are premixed by a high-speed stirrer at a speed of 8000-12000 rpm for 3-5 minutes; in step S2, the shape memory composite and the functional additives are mixed and then melt blended with the premix at a temperature of 180-220°C; in step S3, the mold temperature in the injection molding process is 40-60°C, and the injection pressure is 80-100 MPa.

8. A clamp characterized in that, The TPE clamp material comprises the TPE clamp material according to any one of claims 1 to 5.

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