A polyurethane rubber and its preparation method

Abstract

This invention belongs to the field of rubber, specifically disclosing a polyurethane rubber and its preparation method. This invention uses polycarbonate-type polyurethane instead of traditional polyester, polyether, or polycaprolactone-type polyurethane, resulting in rubber with better resilience, tensile strength, and tensile strength at a given elongation. Simultaneously, the reinforcing filler material is selected with a low specific surface area and high oil absorption value, thus achieving a balance between high tensile strength, tensile strength at a given elongation, and low compression set.

Description

Technical Field

[0001] This invention belongs to the field of rubber, specifically relating to a polyurethane rubber and its preparation method. Background Technology

[0002] Currently, automotive timing belts primarily use a composite material of hydrogenated nitrile butadiene rubber (HNBR) and nylon fabric. HNBR is widely used in automotive timing belts due to its high-temperature resistance, wear resistance, weather resistance, and excellent resilience. Even after prolonged use, the material deforms minimally, maintaining excellent timing belt tracking, and engine noise remains relatively low. Therefore, HNBR has long been the preferred choice in the automotive timing belt industry. From a technical perspective, the use of HNBR in automotive timing belts is impeccable. However, in recent years, due to the booming development of new energy vehicles, HNBR has been widely used in new energy batteries, leading to a surge in HNBR usage and a significant increase in material prices, exceeding the affordability of automotive manufacturers. Therefore, it is necessary to develop a material that can replace HNBR in terms of performance while significantly reducing costs.

[0003] In terms of tensile strength, abrasion resistance, and weather aging resistance, the performance of compounded polyurethane is close to that of HNBR. However, the performance of mainstream compounded polyurethanes on the market, including polyester, polyether, and polycaprolactone types, is slightly different from that of HNBR. Therefore, it is necessary to develop a new polyurethane material whose performance is infinitely close to that of HNBR rubber to meet practical needs. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention provides a polyurethane rubber and a method for preparing the same.

[0005] To achieve the above objectives, the following technical solutions are specifically included:

[0006] A polyurethane rubber comprises the following components in parts by weight: 100 parts of polycarbonate-type polyurethane, 20-80 parts of reinforcing filler, 1-8 parts of accelerator, 2-50 parts of plasticizer, 1-6 parts of antioxidant, and 0.5-5 parts of processing aid.

[0007] The reinforcing filler includes a light-colored reinforcing filler and / or a black reinforcing filler; the light-colored reinforcing filler has an oil absorption value of 120-160 mL / g (the value of adsorbed DBP, i.e., DBP value) and a specific surface area of ​​50-80 m². 2 / g; the black reinforcing filler has an oil absorption value of 100-130 mL / g (DBP value) and a specific surface area of ​​25-40 m². 2 / g.

[0008] In a preferred embodiment of the present invention, the accelerator comprises 0.5-3 parts of vulcanization accelerator and 0.5-5 parts of crosslinking accelerator.

[0009] As a further preferred embodiment of the present invention, the crosslinking promoter includes at least one of triallyl isocyanurate (TAIC), N,N'-p-phenyl bismaleimide (HVA-2), trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), and ethylene glycol dimethacrylate (EGDMA).

[0010] In a further preferred embodiment of the present invention, the crosslinking promoter is TMPTA and EGDMA.

[0011] In a preferred embodiment of the present invention, the black reinforcing filler includes carbon black HS25, and the light-colored reinforcing filler includes white carbon black 532EP.

[0012] In a preferred embodiment of the present invention, the vulcanization accelerator is a peroxide vulcanization system.

[0013] As a further preferred embodiment of the present invention, the peroxide sulfidation system includes at least one of 2,5-di-tert-butylperoxide-2,5-dimethylhexane (bis(2,5-di-5-di-5-di-5-di-di-5-di-di-di-di-tert-butylperoxide-diisopropylbenzene) (BIPB).

[0014] In a preferred embodiment of the present invention, the plasticizer is at least one of ester-based environmentally friendly plasticizers.

[0015] As a further preferred embodiment of the present invention, the ester-based environmentally friendly plasticizer includes at least one of di(butoxyethoxy)ethyl adipic acid (TP95), alkyl sulfonate phenyl ester (Mesamoll), and diisononyl cyclohexanedicarboxylate (DINCH).

[0016] In a preferred embodiment of the present invention, the antioxidant includes one or more of amine antioxidants and substituted phenolic antioxidants, such as antioxidant Naugard 445, antioxidant 1010, antioxidant 1076, etc.

[0017] In a preferred embodiment of the present invention, the processing aid includes at least one of stearic acid, polyethylene wax, and WB222.

[0018] A method for preparing polyurethane rubber includes the following steps: mixing polycarbonate-type polyurethane, processing aids, antioxidants, reinforcing fillers, and plasticizers and mixing them in an intensive mixer; mixing at 140-150°C to discharge the rubber; then re-mixing, sheeting, and allowing it to stand; adding a accelerator and then sheeting it through a thin pass to obtain the polyurethane rubber.

[0019] In a preferred embodiment of the present invention, the number of re-refining cycles is 2-3 times.

[0020] In a preferred embodiment of the present invention, the settling time is 10-24 hours.

[0021] In a preferred embodiment of the present invention, the number of thin passes is 5-6.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) In this invention, polycarbonate-type polyurethane is used instead of traditional polyester, polyether, and polycaprolactone-type polyurethane, which makes the rubber have better properties such as resilience, tensile strength, and tensile strength.

[0024] (2) The reinforcing filler material of the present invention is selected with a low specific surface area and a high oil absorption value, which can take into account the high tensile strength, constant elongation strength and low compression set of rubber.

[0025] (3) The present invention uses two crosslinking aids at the same time, which can balance the vulcanization speed and the degree of crosslinking to obtain high resilience, low compression set and faster vulcanization speed. Detailed Implementation

[0026] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0027] Information on the reinforcing fillers used in the examples and comparative examples:

[0028] Silica N255: Oil absorption value 230 (mL / 100g), specific surface area 175 (m²). 2 / g);

[0029] 532EP silica: oil absorption value 170 (mL / 100g), specific surface area 60 (m²). 2 / g);

[0030] Carbon black N330: oil absorption value 102 (mL / 100g), specific surface area 76 (m²). 2 / g);

[0031] Carbon black HS25: oil absorption value 102 (mL / 100g), specific surface area 28 (m²). 2 / g).

[0032] Examples 1-6 and Comparative Examples 1-4

[0033] The polyurethane rubber was synthesized using the formulation shown in Table 1, and its preparation method is as follows:

[0034] (1) Put polyurethane and 1 / 2 of the amount of processing aid into the mixing chamber, first plasticize for 2 minutes, then put in the remaining 1 / 2 of the amount of processing aid, antioxidant, and 2 / 3 of the amount of reinforcing filler, mix for 2 minutes, then put in the remaining reinforcing filler and plasticizer, mix until 140-150℃ and discharge the glue.

[0035] (2) Re-mill 2-3 times on a two-roll mill, produce sheets, and let stand for 12 hours;

[0036] (3) Add accelerator to open mill, pass through 5-6 times, and produce sheets according to the required thickness and size.

[0037] Table 1

[0038]

[0039]

[0040] The polyurethane rubber products prepared in the above embodiments and comparative examples were subjected to performance tests. The test methods are as follows: (1) Hardness: GB / T 531;

[0041] (2) 100% tensile strength: GB / T 528;

[0042] (3) Elongation at break: GB / T 528;

[0043] (4) Resilience: GB / T 1681;

[0044] (5) Taber wear H22: ASTM D3884;

[0045] (6) Compression set at 100℃ for 22 hours: GB / T 1683;

[0046] (7) 100℃*72h hot air aging: GB / T 3512.

[0047] Table 2

[0048]

[0049] As can be seen from the data in Table 1-2:

[0050] Compared with Comparative Example 1, the polyurethane rubber made from polycarbonate-type polyurethane has significantly better resilience and tensile strength than polyether-type polyurethane, and its compression set is also significantly smaller than that of polyether-type polyurethane.

[0051] Compared with Comparative Examples 1-4, in the system of the present invention, when alkaline silica 532EP or carbon black HS25 is used as a reinforcing filler, the resilience and compression set of the polyurethane rubber are significantly better than those of ordinary silica N255 or carbon black N330, while the tensile strength of the polyurethane rubber is only slightly lower than the latter. This is because, compared with silica N255 or N330, silica 532EP and carbon black HS25 have a smaller specific surface area (at this time, the particle size is larger), and the oil absorption value is only slightly lower than the former two materials. Among them, the larger particle size results in better resilience and compression set of the polyurethane rubber, and the oil absorption value determines its reinforcing performance of the rubber. Therefore, the tensile strength of the polyurethane rubber is only slightly lower than that of the former two materials.

[0052] In addition, suitable vulcanization accelerators, such as TMPTA and EGDMA, are more conducive to crosslinking, thereby improving the 100% tensile strength of the material and making it more suitable for use in the manufacture of automotive timing belt products.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polyurethane rubber, characterized in that, It includes the following components in parts by weight: 100 parts of polycarbonate-type polyurethane, 20-80 parts of reinforcing filler, 2-50 parts of plasticizer, 1-6 parts of antioxidant, 0.5-5 parts of processing aid, and 1-8 parts of accelerator. The reinforcing filler is a light-colored reinforcing filler and / or a black reinforcing filler; The black reinforcing filler is carbon black HS25 having an oil absorption number of 102 mL / 100 g and a specific surface area of 28 m 2 / g, and the light-colored reinforcing filler is white carbon black 532 EP having an oil absorption number of 170 mL / 100 g and a specific surface area of 60 m 2 / g; and the accelerators include 0.5 to 3 parts of a vulcanization accelerator and 0.5 to 5 parts of a crosslinking accelerator.

2. The polyurethane rubber as described in claim 1, characterized in that, The crosslinking accelerator includes at least one of triallyl isocyanurate, N,N'-p-phenylbismaleimide, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and ethylene glycol dimethacrylate; the vulcanization accelerator is a peroxide vulcanization system.

3. The polyurethane rubber as described in claim 2, characterized in that, The crosslinking accelerator is trimethylolpropane triacrylate and ethylene glycol dimethacrylate.

4. The polyurethane rubber as described in claim 2, characterized in that, The peroxide sulfidation system includes at least one of 2,5-di-tert-butylperoxide-2,5-dimethylhexane and di-tert-butylperoxide-diisopropylbenzene.

5. The polyurethane rubber as described in claim 1, characterized in that, The plasticizer is at least one of the ester-based environmentally friendly plasticizers; the antioxidant includes one or more of the amine antioxidants and substituted phenolic antioxidants; the processing aid includes at least one of stearic acid, polyethylene wax, and WB222.

6. The polyurethane rubber as described in claim 5, characterized in that, The ester-based environmentally friendly plasticizer includes at least one of di(butoxyethoxy)ethyl adipate, alkyl sulfonate phenyl ester, and diisononyl cyclohexanedicarboxylate; the antioxidant includes at least one of antioxidant Naugard 445, antioxidant 1010, and antioxidant 1076.

7. A method for preparing polyurethane rubber according to any one of claims 1 to 6, characterized in that, Includes the following steps: Polycarbonate-type polyurethane, processing aids, antioxidants, reinforcing fillers, and plasticizers are mixed and internally mixed at 140-150°C to remove the glue. After re-mixing, sheeting, and standing, accelerators are added, and the mixture is then passed through a thin pass and sheeted to obtain the polyurethane rubber.

8. The method for preparing polyurethane rubber as described in claim 7, characterized in that, Includes at least one of the following (a)-(c): (a) The number of times the refining process is repeated is 2-3 times; (b) The settling time is 10-24 hours; (c) The number of times the thin tube is passed is 5-6 times.

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