Oil-resistant TPV material and preparation method thereof

Abstract

The present invention provides an oil-resistant TPV material and a preparation method thereof. The TPV material provided by the present invention has excellent oil resistance and can take into account comprehensive properties such as good mechanical properties. The oil-resistant TPV material is prepared by using raw materials including the following components in parts by weight: 5-25 parts of PP resin, 30-50 parts of EPDM rubber, 10-30 parts of TPU, 15-40 parts of TPEE, 0.3-1.5 parts of vulcanizing agent, 0.5-1.0 parts of vulcanization accelerator, 3-10 parts of compatibilizer, preferably 5-10 parts, and 1.0-4.2 parts of auxiliary agent; wherein the hardness of the TPU is 60-95ShoreA, and the hardness of the TPEE is 28-40ShoreD.

Description

Technical Field

[0001] The invention relates to the technical field of thermoplastic vulcanizate (TPV), and in particular to an oil-resistant TPV material and a preparation method thereof. Background Art

[0002] Thermoplastic vulcanizate (TPV) refers to a polymer elastomeric material prepared by a dynamic vulcanization process with plastic as the continuous phase and rubber as the dispersed phase. It has excellent tensile strength, elasticity and flex fatigue resistance, as well as good processability and service life. It is widely used in automotive sealing strips, drive shaft sleeves, clean end air pipes, turbocharger pipes and other parts.

[0003] The TPV materials currently used for clean side air pipes of intake assemblies, turbocharger pipes and other engine and peripheral parts have the following defects:

[0004] 1) Traditional PP+EPDM TPV, because EPDM has ethylene propylene and other structures in its molecular structure, which is similar to the alkane structure of oil, it has good compatibility with it. In addition, although PP has the ability to crystallize, it is a non-polar material and has poor oil resistance. In an oil-rich environment, oil penetrates into the EPDM phase through the PP amorphous area, the TPV material absorbs oil and swells, the material volume increases significantly, and the bonding between PP and EPDM inside the material is weakened. This ultimately leads to problems such as oil seepage and performance degradation in the material, limiting the application of this material.

[0005] 2) The PA+AEM oil-resistant TPV materials currently available have a complex preparation process for AEM, which usually consists of two vulcanization steps. In addition, the source of AEM raw materials is single, the supply cannot be guaranteed, and the price is high, which limits its application.

[0006] 3) The PA+NBR type TPV materials currently available have high requirements for the dynamic vulcanization process of NBR and the screw extrusion equipment. The equipment has poor compatibility with the process and high cost, which limits its application. Summary of the invention

[0007] In order to overcome the problem of poor oil resistance of TPV materials in the prior art, the present invention provides an oil-resistant TPV material and a preparation method thereof. The TPV material provided by the present invention has good oil resistance and can take into account good resistance to engine oil penetration and oil aging.

[0008] To achieve the purpose, the present invention provides the following technical solutions:

[0009] In one aspect, the present invention provides an oil-resistant TPV material, which is prepared by using raw materials including the following components in parts by weight:

[0010]

[0011] Wherein, the hardness of the TPU is 60-95 ShoreA, and the hardness of the TPEE is 25-40 ShoreD.

[0012] In the TPV material formula system provided by the present invention, the above-mentioned components are used in combination according to specific dosages, and TPU with a hardness of 60 to 95 Shore A and TPEE with a hardness of 25 to 40 Shore D are used in combination. Through the interaction and organic combination of the components, a TPV material with excellent oil resistance can be obtained.

[0013] In a preferred embodiment, the PP resin is homopolypropylene, and the melt index under the test conditions of 230°C and 2.16kg is less than 5g / 10min, preferably less than 2g / 10min; the EPDM rubber is ethylene propylene diene monomer rubber, and the Mooney viscosity ML (1+4) 125°C (test conditions: 125°C, preheating for 1 minute, testing for 4 minutes, GB 1232) is 55-120, preferably 65-95; the ENB content of the EPDM rubber is 3.5-6.5wt%, preferably 4.0-5.5wt%. In the formulation system of the present invention, the use of the above preferred PP resin and EPDM rubber is conducive to obtaining TPV materials with better performance.

[0014] In a preferred embodiment, the hardness of the TPU is 70-80 ShoreA, and the hardness of the TPEE is 28-40 ShoreD, more preferably 29-33 ShoreD. In the formulation system of the present invention, the use of TPU and TPEE with preferred hardness is conducive to obtaining a material with a relatively ideal hardness (hardness between 65-75A). The obtained material is easy to demold and shape when used for parts, and it is conducive to the material taking into account both better oil resistance and basic mechanical properties. In the present invention, TPU is a polyester or polyether thermoplastic elastomer; TPEE is a thermoplastic polyester elastomer.

[0015] In a preferred embodiment, the weight portion of the compatibilizer is 5-10 parts, more preferably 7-10 parts. The preferred amount of compatibilizer is used to obtain a material with better basic mechanical properties and better resistance to engine oil aging.

[0016] In a preferred embodiment, the weight portion of the compatibilizer is 5-10 parts, more preferably 7-10 parts; and the weight portion of the TPU is 15-30 parts, and the weight portion of the TPEE is 15-30 parts. The inventors found that in the formulation system of the present invention, the compatibilizer, TPU, and TPEE are added in the above-mentioned preferred dosage combination, which can not only significantly improve the comprehensive mechanical properties, but also significantly further improve the oil resistance, so that the material has excellent oil permeability resistance and oil aging resistance. In this preferred embodiment, the compatibilizer is added in 7-10 parts by weight, and the basic mechanical properties and oil resistance of the obtained material are better. More preferably, in the above preferred embodiment, TPU with a hardness of 70-80ShoreA and TPEE with a hardness of 29-33ShoreD are used at the same time, which is conducive to obtaining a material with better comprehensive performance. The obtained material can have excellent oil resistance, mechanical properties and moderate hardness, and is a TPV material that is easy to demold and form.

[0017] In some embodiments, the auxiliary agent includes an antioxidant, a light stabilizer, and a lubricant.

[0018] In some implementations, the weight portions of the antioxidant, light stabilizer and lubricant are 0.3-0.8 parts, 0.4-0.8 parts and 0.2-0.8 parts respectively.

[0019] The antioxidant can be any type conventionally added in the art, and there is no particular limitation on this. In some embodiments, the antioxidant is selected from but not limited to one or more of antioxidants 1010, 1076, 1098, 1024, DLTP, DSTP, 168, and 626.

[0020] The light stabilizer may be a type conventionally added in the art, and there is no particular limitation on this. In some embodiments, the light stabilizer may be selected from, but not limited to, one or two of HALS and UV-531.

[0021] The vulcanizing agent can be a type conventionally added in the art. Preferably, the vulcanizing agent is a peroxide vulcanizing agent; for example, it can be selected from but not limited to dichlorodiphenylmethane, odorless DCP, etc.

[0022] The vulcanization accelerator can be a type conventionally added in the art. In some embodiments, the vulcanization accelerator is selected from a combination of one or more of TMPTA (trimethylolpropane triacrylate), TMPTMA (trimethylolpropane trimethacrylate), TAC (triallyl cyanurate), TAIC (triallyl isocyanurate), BMI (N,N'-4.4'-diphenylmethane bismaleimide), BP (benzoyl peroxide), and 1,2-PBR (1,2-polybutadiene).

[0023] In some embodiments, the compatibilizer is selected from one or more combinations of polypropylene grafted maleic anhydride, polyethylene grafted maleic anhydride, PPE grafted maleic anhydride, POE grafted maleic anhydride, and SEBS grafted maleic anhydride.

[0024] The lubricant may be of a type conventionally used in the art, such as, but not limited to, a combination of one or more of erucamide, silicone, and zinc stearate.

[0025] The second aspect of the present invention also provides a method for preparing the oil-resistant TPV material described above, the preparation method comprising the following steps:

[0026] 1) PP resin, EPDM rubber, vulcanizing agent, vulcanization accelerator and auxiliary agent are firstly plasticized in a twin-screw extruder to obtain a semi-finished product;

[0027] 2) The semi-finished product, TPU, TPEE and compatibilizer are plasticized for the second time in a twin-screw extruder to obtain the oil-resistant TPV material.

[0028] Based on the TPV material formula system provided by the present invention, the preparation is carried out according to the above-mentioned process steps. First, PP and EPDM are plasticized for the first time to obtain a completely dynamically vulcanized TPV material semi-finished product with good fluidity; then the semi-finished product is blended with TPU, TPEE and a compatibilizer for a second plasticization, which is conducive to obtaining a TPV material with significantly improved oil resistance and good comprehensive performance, and a material with a good molding appearance.

[0029] In a preferred embodiment, in step 1), the screw aspect ratio of the twin-screw extruder is greater than 56:1, the screw speed is 500-650r / min, and the temperature condition for the first plasticizing is 160-200°C; in step 2), the screw aspect ratio of the twin-screw extruder is 56:1, the screw speed is 400-500r / min, and the temperature condition for the second plasticizing is 160-200°C. Through the aforementioned step 1), the uniform dispersion and distribution of PP, EPDM and small materials can be completed in one step, and a good dynamic vulcanization effect and a good phase area size can be achieved. Steps 1) and 2) use a preferred screw aspect ratio combination, which can make the polar elastomers TPU and TPEE fully and effectively dispersed and distributed in the continuous phase, which is conducive to obtaining TPV materials with further improved oil resistance.

[0030] The technical solution provided by the present invention has the following beneficial effects:

[0031] The technical solution based on the present invention can provide a TPV material with good oil permeability resistance and oil aging resistance by matching and organically combining the components in the formula system. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0033] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in the art can be used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased commercially.

[0034] Embodiment 1:

[0035] This embodiment provides a highly oil-resistant TPV injection molding material, the formulation system of which includes the following components in parts by weight:

[0036] 25 parts by weight of homopolymer polypropylene resin,

[0037] 50 parts by weight of EPDM rubber,

[0038] 10 parts by weight of TPU,

[0039] 15 parts by weight of TPEE,

[0040] 8 parts by weight of a compatibilizer,

[0041] 0.5 parts by weight of peroxide curing agent,

[0042] 0.5 parts by weight of peroxide vulcanization accelerator,

[0043] 0.3 parts by weight of antioxidant,

[0044] 0.4 parts by weight of light stabilizer,

[0045] 0.3 parts by weight of lubricant.

[0046] Among them, the melt index of homopolymer polypropylene resin (PP resin) is 1.8g / 10min (230℃, 2.16kg); the Mooney viscosity (ML(1+4)125℃) of EPDM rubber is 70, and the ENB content is 4wt%; TPU is a polyester thermoplastic elastomer with a hardness of 75Shore A; TPEE is a polyester elastomer with a hardness of 30Shore D; the vulcanizer is a dipentadienyl vulcanizer; the vulcanization accelerator is TMPTMA; the compatibilizer is polypropylene grafted maleic anhydride; the lubricant is zinc stearate; the antioxidant is 1010, and the light stabilizer is UV-531.

[0047] The above formulation system is prepared into TPV material by the following steps:

[0048] 1) EPDM oil-filled and dynamically vulcanized semi-finished products:

[0049] A twin-screw extruder with a screw length-diameter ratio of 60:1 was used, the screw speed was 600r / min, the conveying section temperature was 160°C, the plasticizing and dynamic reaction temperature was set to 200°C, and the die temperature was set to 200°C. PP resin, EPDM, and vulcanization accelerator were mixed evenly and added from the main feed port, and auxiliary agents (antioxidants, light stabilizers, and lubricants) were added online in the third zone using an oil scale, and vulcanizers were added online in the sixth zone. The TPV semi-finished product was obtained through the first plasticizing in step 1).

[0050] 2) TPV semi-finished products are blended with polar elastomers TPEE and TPU:

[0051] A twin-screw extruder with a screw length-diameter ratio of 56:1 was used, the screw speed was 400 r / min, the conveying section temperature was 160° C., the plasticizing temperature was set to 190° C., and the die temperature was 200° C. The TPV semi-finished product prepared in step 1), TPU, TPEE and compatibilizer were plasticized for the second time in the twin-screw extruder to obtain an oil-resistant TPV material.

[0052] Embodiment 2:

[0053] This embodiment is carried out with reference to embodiment 1, with the main difference being:

[0054] In the formula system, 20 parts by weight of homopolypropylene resin, 40 parts by weight of EPDM rubber, 15 parts by weight of TPU, 15 parts by weight of TPEE, 8 parts by weight of compatibilizer, 0.5 parts by weight of peroxide vulcanizer, 0.5 parts by weight of peroxide vulcanization accelerator, 0.3 parts by weight of antioxidant, 0.4 parts by weight of light stabilizer, and 0.3 parts by weight of lubricant are selected.

[0055] Embodiment 3:

[0056] This embodiment is carried out with reference to embodiment 1, with the main difference being:

[0057] In the formula system, 15 parts by weight of homopolypropylene resin, 30 parts by weight of EPDM rubber, 20 parts by weight of TPU, 25 parts by weight of TPEE, 8 parts by weight of compatibilizer, 0.5 parts by weight of peroxide vulcanizer, 0.5 parts by weight of peroxide vulcanization accelerator, 0.3 parts by weight of antioxidant, 0.4 parts by weight of light stabilizer, and 0.3 parts by weight of lubricant are selected.

[0058] Embodiment 4:

[0059] This embodiment is carried out with reference to embodiment 1, with the main difference being:

[0060] In the formula system, 20 parts by weight of homopolypropylene resin, 40 parts by weight of EPDM rubber, 15 parts by weight of TPU, 15 parts by weight of TPEE, 5 parts by weight of compatibilizer, 0.5 parts by weight of peroxide vulcanizer, 0.5 parts by weight of peroxide vulcanization accelerator, 0.3 parts by weight of antioxidant, 0.4 parts by weight of light stabilizer, and 0.3 parts by weight of lubricant are selected.

[0061] Embodiment 5:

[0062] This embodiment is carried out with reference to embodiment 1, with the main difference being:

[0063] In the formula system, 20 parts by weight of homopolypropylene resin, 40 parts by weight of EPDM rubber, 15 parts by weight of TPU, 15 parts by weight of TPEE, 3 parts by weight of compatibilizer, 0.5 parts by weight of peroxide vulcanizer, 0.5 parts by weight of peroxide vulcanization accelerator, 0.3 parts by weight of antioxidant, 0.4 parts by weight of light stabilizer, and 0.3 parts by weight of lubricant are selected.

[0064] Comparative Example 1 (without adding TPU and TPEE)

[0065] This comparative example was carried out with reference to Example 1, with the main difference being:

[0066] In the formula system, 19 parts by weight of homopolymer polypropylene resin, 79 parts by weight of EPDM rubber, 0.5 parts by weight of peroxide vulcanizer, 0.5 parts by weight of peroxide vulcanization accelerator, 0.3 parts by weight of antioxidant, 0.4 parts by weight of light stabilizer, and 0.3 parts by weight of lubricant are selected.

[0067] Comparative Example 2 (without adding compatibilizer)

[0068] This comparative example was carried out with reference to Example 1, with the main difference being:

[0069] In the formula system, 20 parts by weight of homopolypropylene resin, 40 parts by weight of EPDM rubber, 15 parts by weight of TPU, 15 parts by weight of TPEE, 0.5 parts by weight of peroxide vulcanizer, 0.5 parts by weight of peroxide vulcanization accelerator, 0.3 parts by weight of antioxidant, 0.4 parts by weight of light stabilizer, and 0.3 parts by weight of lubricant are selected.

[0070] Example 6

[0071] This embodiment is carried out with reference to embodiment 1, with the main difference being:

[0072] In the formula system, 20 parts by weight of homopolymer polypropylene resin, 40 parts by weight of EPDM rubber, 15 parts by weight of TPU with a hardness of 60 Shore A, 15 parts by weight of TPEE with a hardness of 25 Shore D, 8 parts by weight of compatibilizer, 0.5 parts by weight of peroxide vulcanizer, 0.5 parts by weight of peroxide vulcanization accelerator, 0.3 parts by weight of antioxidant, 0.4 parts by weight of light stabilizer, and 0.3 parts by weight of lubricant are selected.

[0073] Example 7

[0074] This embodiment is carried out with reference to embodiment 1, with the main difference being:

[0075] In the formula system, 20 parts by weight of homopolymer polypropylene resin, 40 parts by weight of EPDM rubber, 15 parts by weight of TPU with a hardness of 80 Shore A, 15 parts by weight of TPEE with a hardness of 35 Shore D, 8 parts by weight of compatibilizer, 0.5 parts by weight of peroxide vulcanizer, 0.5 parts by weight of peroxide vulcanization accelerator, 0.3 parts by weight of antioxidant, 0.4 parts by weight of light stabilizer, and 0.3 parts by weight of lubricant are selected.

[0076] Table 1 Formulation system of embodiments and comparative examples (parts by weight)

[0077]

[0078] The performance of the TPV materials obtained in the above examples and comparative examples was tested, and the results are shown in Table 2 below.

[0079] Table 2

[0080]

[0081]

[0082] From the experimental results of Examples 1-7 and Comparative Examples 1 and 2, it can be seen that the TPV material obtained by using the formulation system of the present invention has better oil aging resistance and oil penetration resistance. In the thermal degradation performance experiment, the degree of mechanical property attenuation of the material after soaking in engine oil is significantly lower than that of Comparative Examples 1 and 2, and the oil penetration resistance is better. Compared with Example 1, Comparative Example 1 does not add TPU, TPEE and compatibilizer, and the mechanical property of the material after soaking in engine oil is significantly attenuated, and the oil penetration resistance is poor. Comparative Example 2 does not add a compatibilizer, and the basic performance and oil aging resistance of the material are significantly reduced.

[0083] In Examples 1-7, Examples 2-4 use the preferred hardness and dosage of TPU and TPEE, and the preferred dosage of compatibilizer. The resulting TPV material has better comprehensive performance, can take into account better basic mechanical properties and oil resistance, while taking into account relatively moderate hardness (between 65-75A), and has better part formability and demolding performance.

[0084] In Examples 6 and 7, compared with Example 2, the preferred hardness of TPU and TPEE is not adopted; compared with Examples 6 and 7, Example 2 can better balance relatively moderate hardness, good oil resistance and basic mechanical properties.

[0085] Compared with Example 1, Examples 2-3 not only adopt the preferred amount of compatibilizer, but also adopt the preferred amount of TPU and TPEE added, not only the basic mechanical properties are better, but also the oil resistance of TPV materials is significantly improved, and the mechanical property retention rate of materials after oil immersion is significantly improved. Compared with Example 2, Example 5 does not adopt the preferred amount of compatibilizer, the basic mechanical properties of the material are reduced, and the mechanical property retention rate of the material after oil immersion is reduced.

[0086] In general, the oil-resistant injection molding TPV material prepared by the technical solution of the present invention has excellent properties of resistance to oil aging and oil penetration, and the product performance is significantly better than that of traditional processing technology.

[0087] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. An oil-resistant TPV material, characterized in that: The oil-resistant TPV material is prepared by using raw materials including the following components in parts by weight: Wherein, the hardness of the TPU is 60-95 ShoreA, and the hardness of the TPEE is 25-40 ShoreD.

2. The oil-resistant TPV material according to claim 1, characterized in that: The PP resin is homopolymer polypropylene, and the melt index under the test conditions of 230° C. and 2.16 kg is less than 5 g / 10 min; The Mooney viscosity ML (1+4) of the EPDM rubber at 125° C. is 55-120; the ENB content of the EPDM rubber is 3.5-6.5 wt %.

3. The oil-resistant TPV material according to claim 2, characterized in that: The homopolymer polypropylene has a melt index of less than 2 g / 10 min under the test conditions of 230° C. and 2.16 kg.

4. The oil-resistant TPV material according to claim 2, characterized in that: The Mooney viscosity ML (1+4) of the EPDM rubber at 125° C. is 65-95; The ENB content of the EPDM rubber is 4.0-5.5 wt %.

5. The oil-resistant TPV material according to claim 1, characterized in that: The hardness of the TPU is 70-80 Shore A; the hardness of the TPEE is 28-40 Shore D.

6. The oil-resistant TPV material according to claim 5, characterized in that: The hardness of the TPEE is 29-33 Shore D.

7. The oil-resistant TPV material according to any one of claims 1 to 6, characterized in that: The weight portion of the TPU is 15-30 parts, and the weight portion of the TPEE is 15-30 parts.

8. The oil-resistant TPV material according to any one of claims 1 to 6, characterized in that: The weight portion of the compatibilizer is 5-10 parts; Furthermore, the weight portion of the TPU is 15-30 parts, and the weight portion of the TPEE is 15-30 parts.

9. The oil-resistant TPV material according to claim 8, characterized in that: The weight portion of the compatibilizer is 7-10 parts.

10. The oil-resistant TPV material according to any one of claims 1 to 6, characterized in that: The auxiliary agents include antioxidants, light stabilizers and lubricants; The weight portions of the antioxidant, light stabilizer and lubricant are 0.3-0.8 parts, 0.4-0.8 parts and 0.2-0.8 parts respectively.

11. The oil-resistant TPV material according to claim 10, characterized in that: The antioxidant is selected from one or more of antioxidants 1010, 1076, 1098, 1024, DLTP, DSTP, 168, and 626; And / or, the light stabilizer is selected from one or both of HALS and UV-531.

12. The oil-resistant TPV material according to any one of claims 1 to 6, characterized in that: The vulcanizing agent is a peroxide vulcanizing agent; And / or, the vulcanization accelerator is selected from one or more combinations of TMPTA, TMPTMA, TAC, TAIC, BMI, BP, and 1,2-PBR; And / or, the compatibilizer is selected from one or more combinations of polypropylene grafted maleic anhydride, polyethylene grafted maleic anhydride, PPE grafted maleic anhydride, POE grafted maleic anhydride, and SEBS grafted maleic anhydride.

13. The method for preparing the oil-resistant TPV material according to any one of claims 1 to 12, characterized in that: The preparation method comprises the following steps: 1) PP resin, EPDM rubber, vulcanizing agent, vulcanization accelerator and auxiliary agent are firstly plasticized in a twin-screw extruder to obtain a semi-finished product; 2) The semi-finished product, TPU, TPEE and compatibilizer are plasticized for the second time in a twin-screw extruder to obtain the oil-resistant TPV material.

14. The preparation method according to claim 13, characterized in that: In step 1), the screw aspect ratio of the twin-screw extruder is greater than 56:1, the screw speed is 500-650r / min, and the temperature condition of the first plasticizing is 160-200°C; In step 2), the screw aspect ratio of the twin-screw extruder is 56:1, the screw speed is 400-500 r / min, and the temperature condition of the second plasticizing is 160-200°C.

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