Thermoplastic elastomer material as well as preparation method and application thereof

Abstract

The invention discloses a thermoplastic elastomer material as well as a preparation method and application thereof, and belongs to the field of high polymer materials. According to the invention, the polar elastomer is added into the SEBS material, the proportion of the melt index of the polar elastomer in the formula to the melt index of the SEBS and plasticizer mixture is controlled in a suitable range, and the proper compatilizer is selected, so that the bonding strength of the material on PC, ABS and PC / ABS alloy is improved; the obtained thermoplastic elastomer material is suitable for preparing products such as automobile wireless charging panel rubber coating and sound equipment foot pads.

Description

Technical Field

[0001] This application relates to the field of polymer materials, and particularly to a thermoplastic elastomer material, its preparation method and application. Background Art

[0002] In the automotive and electronics industries, PC (polycarbonate) and ABS (acrylonitrile-butadiene-styrene terpolymer) are widely used due to their excellent comprehensive properties. With the gradual increase in people's requirements for the aesthetics and user experience of products, the surfaces of more and more PC and ABS parts are coated with thermoplastic elastomers (TPEs), such as the overmolding of automotive wireless charging panels and the gaskets of speakers. For such coated structures, the TPE is generally directly injection-molded onto the surfaces of PC, ABS, or PC / ABS alloy parts through insert injection molding or two-color injection molding. To ensure that the TPE does not fall off the surfaces of PC, ABS, or PC / ABS alloy parts, good adhesion needs to be maintained between the TPE and PC, ABS, or PC / ABS alloy.

[0003] PC, ABS, and PC / ABS alloy have a certain polarity and poor compatibility with common TPE materials (such as the hydrogenated copolymer of styrene-butadiene SEBS), resulting in poor adhesion of the TPE material to PC, ABS, and PC / ABS alloy. Therefore, it is urgent to develop a technology to improve the adhesion of the TPE material to PC, ABS, and PC / ABS alloy. Summary of the Invention

[0004] Based on the defects existing in the prior art, the purpose of this application is to provide a thermoplastic elastomer material, its preparation method and application, and the obtained thermoplastic elastomer material has high adhesion strength and good adhesion effect on PC, ABS, and PC / ABS alloy.

[0005] To achieve the above purpose, in the first aspect, this application provides a thermoplastic elastomer material, which comprises the following components in parts by weight: 24 - 36 parts of a hydrogenated copolymer of styrene-butadiene, 30 - 50 parts of a polar elastomer, 3 - 5 parts of a compatibilizer, 25 - 35 parts of a plasticizer, 0 - 20 parts of a filler, and 0 - 2 parts of an auxiliary agent; The thermoplastic elastomer material satisfies: 10 ≤ A / B ≤ 30, wherein, A is the melt index of the polar elastomer at 190 °C and 2.16 kg, and the unit is g / 10 min; B is the melt index of the mixture obtained by mixing the hydrogenated copolymer of styrene-butadiene and the plasticizer according to their ratios in the thermoplastic elastomer material at 190 °C and 2.16 kg, and the unit is g / 10 min.

[0006] The inventors' research found that adding polar elastomers to SEBS can improve its compatibility with PC and ABS, thereby enhancing its adhesion strength to PC, ABS, and PC / ABS alloys. Controlling the ratio of the melt index of the polar elastomer to the melt index of the SEBS and plasticizer mixture (i.e., A / B) within the above suitable range can promote the migration of the polar elastomer in the thermoplastic elastomer material to the bonding interface during the injection molding process, while avoiding obvious phase separation between the polar elastomer and SEBS, ensuring that the thermoplastic elastomer material itself has good mechanical properties, and preventing the thermoplastic elastomer material from breaking during the adhesion strength test, thus achieving the improvement of the adhesion strength of the thermoplastic elastomer material to PC, ABS, and PC / ABS alloys.

[0007] The SEBS is 24 to 36 parts by weight, such as 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, or the range formed by any two of the above values. Preferably, the weight percentage content of the SEBS in the thermoplastic elastomer material is above 15%, such as 15%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 38.3%, or the range formed by any two of the above values.

[0008] The polar elastomer is 30 to 50 parts by weight, such as 30 parts by weight, 32 parts by weight, 34 parts by weight, 36 parts by weight, 38 parts by weight, 40 parts by weight, 42 parts by weight, 44 parts by weight, 46 parts by weight, 48 parts by weight, 50 parts by weight, or the range formed by any two of the above values.

[0009] The compatibilizer is 3 to 5 parts by weight, such as 3 parts by weight, 3.2 parts by weight, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.4 parts by weight, 4.6 parts by weight, 4.8 parts by weight, 5 parts by weight, or the range formed by any two of the above values.

[0010] The plasticizer is 25 to 35 parts by weight, such as 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, or the range formed by any two of the above values.

[0011] The filler is 0 to 20 parts by weight, such as 0 parts by weight, 2 parts by weight, 4 parts by weight, 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, or the range formed by any two of the above values.

[0012] The auxiliary agent is 0 to 2 parts by weight, such as 0 part by weight, 0.2 part by weight, 0.4 part by weight, 0.6 part by weight, 0.8 part by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight or the range formed by any two of the above values.

[0013] The value of A / B is 10 to 30, such as 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 or the range formed by any two of the above values.

[0014] The A and the B are measured according to ASTM-D1238-2010.

[0015] Preferably, the A is 9 to 16 g / 10min, such as 9 g / 10min, 10 g / 10min, 11 g / 10min, 12 g / 10min, 13 g / 10min, 14 g / 10min, 15 g / 10min, 16 g / 10min or the range formed by any two of the above values.

[0016] Preferably, the B is 0.4 to 1.5 g / 10min, such as 0.4 g / 10min, 0.5 g / 10min, 0.6 g / 10min, 0.7 g / 10min, 0.8 g / 10min, 0.9 g / 10min, 1.0 g / 10min, 1.1 g / 10min, 1.2 g / 10min, 1.3 g / 10min, 1.4 g / 10min, 1.5 g / 10min or the range formed by any two of the above values.

[0017] The value of B can be regulated by adjusting the ratio of SEBS to the plasticizer, the kinematic viscosity of SEBS at 10 wt.% content in toluene solution at 25°C, etc.

[0018] The ratio of the total weight of the styrene-butadiene hydrogenated copolymer and the plasticizer to the weight of the polar elastomer is 1 to 2.3, such as 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.3 or the range formed by any two of the above values. Preferably, the ratio of the total weight of the styrene-butadiene hydrogenated copolymer and the plasticizer to the weight of the polar elastomer is 1.2 to 1.8, so that the polar elastomer can obtain a higher bonding strength on PC, ABS and PC / ABS alloys at a relatively low addition amount of SEBS and the plasticizer, and the cost performance is higher.

[0019] Preferably, the weight percentage of styrene in the SEBS is 20% - 40%. For example, the weight percentage of styrene in the SEBS is 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40% or any range formed by any two of the above values. The weight percentage of styrene in the SEBS is detected with reference to ASTM D5775 - 2019.

[0020] Preferably, the kinematic viscosity of the SEBS at a content of 10 wt.% in toluene solution at 25°C is 300 - 2000 cP. For example, the kinematic viscosity of the hydrogenated styrenic elastomer at a content of 10 wt% in toluene solution at 25°C is 300 cP, 400 cP, 500 cP, 700 cP, 1000 cP, 1200 cP, 1500 cP, 1800 cP, 2000 cP or any range formed by any two of the above values. The kinematic viscosity of the SEBS is measured according to ASTM D2196 - 2019.

[0021] Preferably, the polar elastomer includes at least one of thermoplastic polyurethane (TPU) and polyester elastomer (TPEE).

[0022] Preferably, the thermoplastic polyurethane includes at least one of thermoplastic polyester - type polyurethane and thermoplastic polyether - type polyurethane.

[0023] Preferably, the compatibilizer includes at least one of styrene - butadiene hydrogenated copolymer grafted maleic anhydride (SEBS - g - MAH) and POE grafted maleic anhydride (POE - g - MAH). Compared with POE - g - MAH, using SEBS - g - MAH results in better adhesion strength of the thermoplastic elastomer material on PC, ABS and PC / ABS alloy.

[0024] Preferably, the grafting rate of maleic anhydride (i.e., MAH) in the styrene - butadiene hydrogenated copolymer grafted maleic anhydride is 0.8 wt.% - 1.5 wt.%, such as 0.8 wt.%, 0.9 wt.%, 1.0 wt.%, 1.1 wt.%, 1.2 wt.%, 1.3 wt.%, 1.4 wt.%, 1.5 wt.% or any range formed by any two of the above values.

[0025] Preferably, the grafting rate of maleic anhydride in the POE - g - MAH is 1.0 wt.% - 1.5 wt.%, such as 1.0 wt.%, 1.1 wt.%, 1.2 wt.%, 1.3 wt.%, 1.4 wt.%, 1.5 wt.% or any range formed by any two of the above values.

[0026] The grafting ratio of maleic anhydride in the SEBS-g-MAH and the grafting ratio of maleic anhydride in the POE-g-MAH are measured by acid-base titration. For example, a certain amount of SEBS-g-MAH or POE-g-MAH is accurately weighed and placed in a conical flask, an excessive amount of standard alkali solution is added, and the maleic anhydride on the grafted product is completely neutralized by heating. Then, the excessive alkali is titrated with a standard acid solution, and the content of maleic anhydride is calculated to obtain the grafting ratio.

[0027] Preferably, the plasticizer is an oil, and the oil includes at least one of white oil, paraffin oil, naphthenic oil, and aromatic oil.

[0028] Preferably, the kinematic viscosity of the plasticizer at 40 °C is 30-45 mm² / s. For example, the kinematic viscosity of the plasticizer at 40 °C is 30 mm² / s, 32 mm² / s, 34 mm² / s, 36 mm² / s, 38 mm² / s, 40 mm² / s, or any range formed by any two of the above values.

[0029] The kinematic viscosity of the plasticizer is measured with reference to ASTM D445-2015.

[0030] Preferably, the filler includes at least one of calcium carbonate, talcum powder, and montmorillonite.

[0031] Preferably, the average particle size (i.e., Dv50) of the filler is 50-300 nm. The average particle size of the filler is tested with a laser particle size analyzer.

[0032] Preferably, the auxiliary agent includes at least one of an antioxidant, a light stabilizer, and a lubricant.

[0033] Exemplarily, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0034] Exemplarily, the light stabilizer includes at least one of LA-402AF, UV-1600, and UV-3529.

[0035] The thermoplastic elastomer material may further contain at least one of TPU and TPEE. For example, the TPU is 30-50 parts by weight, and / or the TPEE is 30-50 parts by weight.

[0036] In a second aspect, the present application provides a method for preparing the thermoplastic elastomer material, including the following steps: Mix and disperse all the raw materials, melt and extrude, and granulate to obtain the thermoplastic elastomer material.

[0037] Preferably, the temperature of the melt extrusion is 190-230 °C.

[0038] Preferably, the melt extrusion is carried out in a twin-screw extruder, and the ratio of the length to the diameter of the twin-screw extruder is (36-60):1, and the screw rotation speed is 300-400 r / min.

[0039] In a third aspect, the present application also provides an application of the thermoplastic elastomer material in encapsulating an automotive wireless charging panel or a sound insulation foot pad.

[0040] In a fourth aspect, the present application further provides an encapsulation product, including a matrix material and an encapsulating material coated on the surface of the matrix material, and the encapsulating material is the thermoplastic elastomer material.

[0041] Preferably, the matrix material includes at least one of PC and ABS.

[0042] Compared with the prior art, the beneficial effects of the present application are as follows: (1) By adding a polar elastomer to the SEBS material, controlling the ratio of the melt index of the polar elastomer in the formulation to the melt index of the mixture of SEBS and plasticizer within an appropriate range, and selecting a suitable compatibilizer, the present application improves the adhesion strength on PC, ABS, and PC / ABS alloys.

[0043] (2) Under the combined action of the components in specific contents, the thermoplastic elastomer material of the present application has high adhesion strength on PC, ABS, and PC / ABS alloys, and is suitable for preparing products such as encapsulating automotive wireless charging panels and sound insulation foot pads. Specific Embodiments

[0044] In order to better illustrate the purpose, technical solutions, and advantages of the present application, the present application will be further described below in conjunction with specific examples and comparative examples. The purpose is to understand the content of the present application in detail, rather than to limit the present application. All other examples obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application. The experimental reagents and instruments involved in the implementation of the present application are all common ordinary reagents and instruments unless otherwise specified. In the present application, for the technical features described in an open-ended manner, a closed technical solution composed of the listed features is included, as well as an open technical solution including the listed features.

[0045] The following examples and comparative examples all provide a thermoplastic elastomer material. The formulations of these thermoplastic elastomer materials are shown in Tables 1 and 2 (in the tables, (SEBS + plasticizer) / polar elastomer refers to the ratio of the total weight of the hydrogenated copolymer of styrene-butadiene and plasticizer to the weight of the polar elastomer). Their preparation methods include the following steps: Mix and disperse all the raw materials and then feed them into a twin-screw extruder, melt extrude, and pelletize to obtain the thermoplastic elastomer material; The screw length-to-diameter ratio of the twin-screw extruder is 48:1, the screw speed is 350 r / min, and the melt extrusion temperature is 200°C.

[0046] The raw material information used in the above examples and comparative examples is as follows, and unless otherwise specified, they are all commercially available raw materials. In addition, the component raw materials used in each parallel experiment are all of the same kind: SEBS 1: The dynamic viscosity of 10wt.% in 25℃ toluene solution is 400cP, the weight percentage of styrene is 31%, model SEBS 7554, manufacturer Li Changrong; SEBS 2: The dynamic viscosity of 10wt.% in 25℃ toluene solution is 1500cP, the weight percentage of styrene is 33%, model YH-503, manufacturer Yuehua Chemical; SEBS 3: The dynamic viscosity of 10wt.% in 25℃ toluene solution is 2000cP, the weight percentage of styrene is 33%, model SEBS 7551, manufacturer Li Changrong; Polar elastomer 1: TPU, model HY-185A, manufacturer Haoyi; Polar elastomer 2: TPU, model 680AS-3, manufacturer Lianjing; Polar elastomer 3: TPU, model HF-85AE, manufacturer Huafeng; Polar elastomer 4: TPEE, model H28DFE, manufacturer Hechuang; Compatibilizer 1: SEBS-g-MAH, MAH grafting rate 1.0wt.%, GPM5601, Ningbo Nengzhiguang; Compatibilizer 2: POE-g-MAH, MAH grafting rate 1.0wt.%, model W1A, manufacturer Coase; Plasticizer 1: white oil, kinematic viscosity at 40°C is 31.5 mm² / s, model 150N, manufacturer: Formosa Plastics; Plasticizer 2: paraffin oil, kinematic viscosity at 40°C is 43 mm² / s, model PW-32, manufacturer’s product; Filler: calcium carbonate, commercially available; Additives: antioxidant 1010 and antioxidant 168, the mass ratio of the two is 1:1, commercially available.

[0047] The melt index (i.e., A) values of polar elastomers 1 to 4 at 190°C and 2.16 kg are shown in Tables 1 and 2. The SEBS and plasticizer raw materials used in the above examples and comparative examples and the resulting thermoplastic elastomer materials were subjected to the following performance tests: (1) Put the used SEBS and plasticizer into a high-speed mixer according to their proportions in the thermoplastic elastomer material (25°C, 800 rpm, 15 min) for mixing and dispersion to obtain a mixture of SEBS and plasticizer. Test the melt index of this mixture at 190°C and 2.16 kg according to ASTM-D1238-2010.

[0048] (2) Inject the obtained thermoplastic elastomer material onto the surface of ABS (model KF-730, manufacturer Liaoning Jinfa) or PC (model PC 2220, manufacturer Wanhua Chemical) at a temperature of 200°C. After placing it at 23°C for 48 h, conduct a 90° peel test at 23°C according to GB / T 7760-2003.

[0049] The test results are shown in Table 1 and Table 2.

[0050] Table 1 Table 2 It can be seen from the above data that the thermoplastic elastomer materials of the embodiments of the present application have good adhesion effects and high adhesion strengths on ABS and PC. For example, the peel force on ABS is above 4.1 N / mm, and the peel force on PC is above 4.2 N / mm.

[0051] In Comparative Examples 1-4, due to the too low or too high A / B value, the adhesion strengths of the obtained thermoplastic elastomer materials on ABS and PC are relatively low.

[0052] By comparing Examples 1, 11-14, it can be known that when the ratio of the total weight of the styrene-butadiene hydrogenated copolymer and the plasticizer to the weight of the polar elastomer is 1.2-1.8, the polar elastomer can enable the material to obtain a higher adhesion strength on PC, ABS, and PC / ABS alloy at a relatively low addition amount, and the cost performance is higher.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application rather than to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A thermoplastic elastomer material, characterized in that, Comprising the following components in parts by weight: 24 - 36 parts of a hydrogenated copolymer of styrene - butadiene, 30 - 50 parts of a polar elastomer, 3 - 5 parts of a compatibilizer, 25 - 35 parts of a plasticizer, 0 - 20 parts of a filler, 0 - 2 parts of an auxiliary agent; The thermoplastic elastomer material satisfies: 10 ≤ A / B ≤ 30, wherein, A is the melt index of the polar elastomer at 190 °C and 2.16 kg, in units of g / 10 min; B is the melt index of the mixture obtained by mixing the hydrogenated copolymer of styrene - butadiene and the plasticizer according to their ratios in the thermoplastic elastomer material at 190 °C and 2.16 kg, in units of g / 10 min.

2. The thermoplastic elastomer material according to claim 1, characterized in that The A is 9 - 16 g / 10 min.

3. The thermoplastic elastomer material according to claim 1, characterized in that, The B is 0.4 - 1.5 g / 10 min.

4. The thermoplastic elastomer material according to claim 1, characterized in that, The ratio of the total weight of the hydrogenated copolymer of styrene - butadiene and the plasticizer to the weight of the polar elastomer is 1.2 - 1.

8.

5. The thermoplastic elastomer material according to claim 1, characterized in that, The kinematic viscosity of the hydrogenated copolymer of styrene - butadiene at a content of 10 wt.% in a toluene solution at 25 °C is 300 - 2000 cP.

6. The thermoplastic elastomer material according to claim 1, wherein The polar elastomer includes at least one of thermoplastic polyurethane and polyester elastomer; and / or The plasticizer is an oil, and the oil includes at least one of white oil, paraffin oil, naphthenic oil and aromatic oil; and / or The compatibilizer includes at least one of a hydrogenated copolymer of styrene - butadiene grafted with maleic anhydride and POE grafted with maleic anhydride; and / or The filler includes at least one of calcium carbonate, talcum powder and montmorillonite; and / or The auxiliary agent includes at least one of an antioxidant and a light stabilizer.

7. The preparation method of the thermoplastic elastomer material according to any one of claims 1 to 6, characterized in that, Comprising the following steps: Mix and disperse all raw materials, melt - extrude, and pelletize to obtain the thermoplastic elastomer material.

8. The application of the thermoplastic elastomer material according to any one of claims 1 - 6 in the encapsulation of an automotive wireless charging panel or an audio footpad.

9. A coated product, characterized in that, Comprising a matrix material and a coating material coated on the surface of the matrix material, and the coating material is the thermoplastic elastomer material according to any one of claims 1 - 6.

10. The overmolded product according to claim 9, characterized in that, The matrix material includes at least one of PC and ABS.

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