A biodegradable nitrile rubber, its preparation method, and its application in gloves

Abstract

This invention relates to the field of nitrile butadiene rubber (NBR) technology, and discloses a biodegradable NBR, its preparation method, and its application in gloves. The biodegradable NBR of this invention comprises 60-80 parts by weight of NBR, 3-6 parts by weight of filler, 1.2-1.8 parts by weight of vulcanizing agent, 20-40 parts by weight of polylactic acid (PLA), and 5-12 parts by weight of cyanopolyester. The cyanopolyester of this invention improves the compatibility between PLA and NBR, resulting in a thermoplastic PLA-NBR composite material with higher tensile strength and tear strength, exhibiting excellent mechanical properties. The cyanopolyester's main chain contains a large number of biodegradable ester groups, and the addition of biodegradable PLA further enhances the biodegradability of the NBR material, making it more environmentally friendly and suitable for practical applications in biodegradable gloves.

Description

Technical Field

[0001] This invention relates to the field of nitrile rubber technology, specifically to a biodegradable nitrile rubber, its preparation method, and its application in gloves. Background Technology

[0002] Nitrile rubber (NBR) possesses excellent oil resistance, chemical corrosion resistance, and abrasion resistance, making it widely used in gloves, gaskets, seals, and cable materials. To improve the mechanical properties of NBR, it is blended and vulcanized with high-performance plastics, resulting in thermoplastic vulcanizates with better processability and mechanical properties. Polylactic acid (PLA) exhibits excellent biodegradability, is environmentally friendly, and has high mechanical strength. Adding PLA to NBR can solve the problems of NBR's lack of biodegradability and relatively low mechanical strength.

[0003] Patent CN107400344B discloses a super-tough PLA / NBR bio-based thermoplastic vulcanizate with shape memory function and its preparation method. Using PLA-g-NBR grafts as compatibilizers, the prepared PLA / NBR bio-based thermoplastic vulcanizate exhibits excellent tensile strength and other mechanical properties. Compared to that patent, this invention not only improves the elongation at break and tear strength of nitrile butadiene rubber, but also further enhances the biodegradability of polylactic acid-nitrile butadiene rubber. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a biodegradable nitrile rubber, its preparation method, and its application in gloves, solving the problem of poor compatibility between nitrile rubber and polylactic acid, while simultaneously improving the mechanical properties and biodegradability of nitrile rubber.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a biodegradable nitrile rubber and its preparation method: the raw materials of the biodegradable nitrile rubber include 60-80 parts by weight of nitrile rubber, 3-6 parts by weight of filler, 0.5-1.2 parts by weight of activator, 0.6-1 parts by weight of antioxidant, 1.2-1.8 parts by weight of vulcanizing agent, 0.8-1.5 parts by weight of accelerator, 20-40 parts by weight of polylactic acid, 1-3 parts by weight of plasticizer, and 5-12 parts by weight of cyanopolyester.

[0006] The preparation method of biodegradable nitrile rubber is as follows:

[0007] (1) Add diacid diglycidyl ester and diamine monomer to ethanol, stir the reaction, remove ethanol by vacuum distillation, wash the product with petroleum ether, and dry to obtain diacid diglycidyl ester-diamine polymer. The preparation reaction formula is:

[0008] .

[0009] (2) Add diglycidyl diacidate-diamine polymer to N,N-dimethylformamide, stir, add acrylonitrile, and react. Remove N,N-dimethylformamide by vacuum distillation, wash the product with petroleum ether, and dry to obtain cyanopolyester. The preparation reaction formula is:

[0010] .

[0011] (3) Add nitrile rubber to a two-roll mill for plasticizing, then add filler, activator and antioxidant for mixing, and sheet to obtain nitrile rubber compound.

[0012] (4) Mix polylactic acid, plasticizer and cyanopolyester, add to open mill for plasticizing, then add nitrile rubber compound and mix, finally add vulcanizing agent and accelerator, vulcanize, and sheet to obtain biodegradable nitrile rubber.

[0013] Furthermore, the filler includes zinc oxide.

[0014] Furthermore, the active agent includes stearic acid.

[0015] Furthermore, the vulcanizing agent includes dicumyl peroxide.

[0016] Furthermore, plasticizers include dioctyl phthalate.

[0017] Furthermore, antioxidants include antioxidant D and antioxidant RD.

[0018] Furthermore, the accelerators include accelerator TMTD and accelerator CZ.

[0019] Furthermore, in (1), the reaction temperature is 70-80℃ and the reaction time is 18-24h.

[0020] Furthermore, (1) the amount of diglycidyl ester is 100 parts by weight and the amount of diamine monomer is 26-38 parts by weight.

[0021] Furthermore, (1) diglycidyl esters include diglycidyl succinate and diglycidyl adipic acid.

[0022] Furthermore, in (1), the molecular formula of the diamine monomer is NH2-(CH2). n -NH2, n includes 2-10.

[0023] Furthermore, (2) the amount of diglycidyl ester-diamine polymer is 100 parts by weight and the amount of acrylonitrile is 20-45 parts by weight.

[0024] Furthermore, in (2), the reaction temperature is 20-50℃ and the reaction time is 12-24h.

[0025] Furthermore, the temperature for sizing in (4) is 160-170℃.

[0026] Furthermore, the vulcanization time in (4) is 4-8 min.

[0027] Furthermore, biodegradable nitrile rubber is used in gloves.

[0028] The beneficial technical effects of this invention are as follows: A ring-opening polymerization reaction is carried out between diglycidyl diacidate and diamine to obtain a polymer containing imino groups. This polymer is then subjected to a Michael addition reaction with acrylonitrile to obtain a cyanopolyester. Finally, this cyanopolyester is blended and vulcanized with nitrile rubber compound, polylactic acid, etc., to obtain biodegradable nitrile rubber. The main chain of this cyanopolyester contains polyester molecular chains similar to those of polylactic acid, while a large number of cyano groups are introduced into the side chains. Due to its similar polarity to nitrile rubber, the cyanopolyester can act as a compatibilizer, improving the compatibility between polylactic acid and nitrile rubber. The resulting thermoplastic polylactic acid-nitrile rubber composite material exhibits higher tensile strength and tear strength, demonstrating excellent mechanical properties.

[0029] The cyanopolyester of this invention contains a large number of biodegradable ester groups in its main chain, and the hydroxyl groups in its side chain can improve the hydrophilicity of the polyester molecular chain and accelerate the hydrolysis of the polyester ester groups. At the same time, the addition of biodegradable polylactic acid further improves the biodegradability of nitrile rubber material, making it more green and environmentally friendly, and has good practical applications in biodegradable gloves and other fields. Detailed Implementation

[0030] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0031] The following nitrile rubber, model N 3330GRN, is from Guangzhou Ke'en Materials Co., Ltd. The polylactic acid, model PDLLA, is from Dongguan Xiuzhisheng Plastics Co., Ltd.

[0032] Prepared according to the method described in the journal *Mol. BioSyst.*, 2011, 7, 1254-1262, in the paper "Biodegradable cross-linked poly(amino alcohol esters) based on LMW PEI for gene delivery", the structural formula is as follows: .

[0033] Example 1:

[0034] (1) Add 40g of diglycidyl succinate and 10.4g of ethylenediamine to 400mL of ethanol, heat to 75℃, stir and react for 24h, reflux during the reaction, remove ethanol by vacuum distillation, wash the product with petroleum ether, dry, and obtain diglycidyl succinate-diamine polymer.

[0035] (2) Add 60g of diglycidyl diacid diamine polymer to 0.8L of N,N-dimethylformamide, stir and then add 12g of acrylonitrile. Stir and react at 30℃ for 12h. Remove N,N-dimethylformamide by vacuum distillation, wash the product with petroleum ether, and dry to obtain cyanopolyester.

[0036] (3) Add 800g of nitrile rubber to a two-roll mill for plasticizing, then add 60g of zinc oxide, 12g of stearic acid and 9g of antioxidant RD for mixing, and sheet out to obtain nitrile rubber compound.

[0037] (4) Mix 200g polylactic acid, 10g dioctyl phthalate and 50g cyanopolyester, add them to a two-roll mill, plasticize at 160℃, then add nitrile rubber compound, mix, and finally add 16g dicumyl peroxide and 10g accelerator TMTD, vulcanize for 8min, and sheet to obtain biodegradable nitrile rubber.

[0038] Example 2:

[0039] (1) Add 40g of diglycidyl succinate and 15.2g of butanediamine to 500mL of ethanol, heat to 80℃, stir and react for 18h, reflux during the reaction, remove ethanol by vacuum distillation, wash the product with petroleum ether, dry, and obtain diglycidyl succinate-diamine polymer.

[0040] (2) Add 60g of diglycidyl diacid diamine polymer to 1L of N,N-dimethylformamide, stir and then add 20g of acrylonitrile. Stir and react at 20℃ for 24h. Remove N,N-dimethylformamide by vacuum distillation, wash the product with petroleum ether, and dry to obtain cyanopolyester.

[0041] (3) Add 700g of nitrile rubber to a two-roll mill for plasticizing, then add 50g of zinc oxide, 8g of stearic acid and 10g of antioxidant RD for mixing, and sheet out to obtain nitrile rubber compound.

[0042] (4) Mix 300g polylactic acid, 22g dioctyl phthalate and 85g cyanopolyester, add them to a two-roll mill, plasticize at 170°C, then add nitrile rubber compound, mix, and finally add 18g dicumyl peroxide and 15g accelerator CZ, vulcanize for 5 minutes, and sheet to obtain biodegradable nitrile rubber.

[0043] Example 3:

[0044] (1) Add 40g of diglycidyl succinate and 12.9g of propylenediamine to 500mL of ethanol, heat to 70℃, stir and react for 24h, reflux during the reaction, remove ethanol by vacuum distillation, wash the product with petroleum ether, dry, and obtain diglycidyl succinate-diamine polymer.

[0045] (2) Add 60g of diglycidyl diacidate-diamine polymer to 1L of N,N-dimethylformamide, stir and add 27g of acrylonitrile, heat to 50℃ and react for 12h, remove N,N-dimethylformamide by vacuum distillation, wash the product with petroleum ether and dry to obtain cyanopolyester.

[0046] (3) Add 600g of nitrile rubber to a two-roll mill for plasticizing, then add 30g of zinc oxide, 5g of stearic acid and 6g of antioxidant D for mixing, and sheet out to obtain nitrile rubber compound.

[0047] (4) Mix 400g polylactic acid, 30g dioctyl phthalate and 120g cyanopolyester, add them to a two-roll mill, plasticize at 170°C, then add nitrile rubber compound, mix, and finally add 12g dicumyl peroxide and 8g accelerator CZ, vulcanize for 4 minutes, and sheet to obtain biodegradable nitrile rubber.

[0048] Comparative Example 1 differs from Example 1 in that cyanopolyester is not added.

[0049] (1) Add 800g of nitrile rubber to a two-roll mill for plasticizing, then add 60g of zinc oxide, 12g of stearic acid and 9g of antioxidant RD for mixing, and sheet out to obtain nitrile rubber compound.

[0050] (2) Add 200g polylactic acid and 10g dioctyl phthalate to a two-roll mill and plasticize at 160°C. Then add nitrile rubber compound and mix. Finally add 16g dicumyl peroxide and 10g accelerator TMTD, vulcanize for 8 minutes, and sheet to obtain biodegradable nitrile rubber.

[0051] Comparative Example 2 differs from Example 1 in that it uses diacid diglycidyl ester-diamine polymer instead of cyanopolyester.

[0052] (1) Add 800g of nitrile rubber to a two-roll mill for plasticizing, then add 60g of zinc oxide, 12g of stearic acid and 9g of antioxidant RD for mixing, and sheet out to obtain nitrile rubber compound.

[0053] (2) 200g polylactic acid, 10g dioctyl phthalate and 50g diglycidyl diacid diamine polymer were mixed in place of cyanopolyester and added to a two-roll mill. The mixture was plasticized at 160°C. Then, nitrile rubber compound was added and mixed. Finally, 16g dicumyl peroxide and 10g accelerator TMTD were added and vulcanized for 8 minutes. The mixture was then sheeted to obtain biodegradable nitrile rubber.

[0054] Comparative Example 3 differs from Example 1 in that 1,4-butanediol diglycidyl ether is used instead of diglycidyl succinate.

[0055] (1) Add 40g of 1,4-butanediol diglycidyl ether and 10.4g of ethylenediamine to 400mL of ethanol, heat to 75℃, stir and react for 24h, reflux during the reaction, remove ethanol by vacuum distillation, wash the product with petroleum ether, dry, and obtain butanediol diglycidyl ether-diamine polymer.

[0056] (2) Add 60g of butanediol diglycidyl ether-diamine polymer to 0.8L of N,N-dimethylformamide, stir and then add 12g of acrylonitrile. Stir and react at 30℃ for 12h. Remove N,N-dimethylformamide by vacuum distillation, wash the product with petroleum ether, and dry to obtain cyano polymer.

[0057] (3) Add 800g of nitrile rubber to a two-roll mill for plasticizing, then add 60g of zinc oxide, 12g of stearic acid and 9g of antioxidant RD for mixing, and sheet out to obtain nitrile rubber compound.

[0058] (4) Mix 200g polylactic acid, 10g dioctyl phthalate and 50g cyanopolymer, add to open mill, plasticize at 160℃, add nitrile rubber compound, mix, and finally add 16g dicumyl peroxide and 10g accelerator TMTD, vulcanize for 8min, and sheet to obtain biodegradable nitrile rubber.

[0059] Comparative Example 4 differs from Example 1 in that it uses polyethylene succinate instead of diglycidyl diacid diamine polymer.

[0060] (1) Add 40g of succinic acid and 21g of ethylene glycol to the reaction vessel, heat to 170°C in a nitrogen atmosphere, stir until no water is generated, add 0.25g of antimony trioxide, evacuate and control the vacuum degree to 50Pa, heat to 230°C, stir and react for 5h, cool and add the product to chloroform, stir and add methanol to precipitate, filter, dry to obtain poly(ethylene succinate).

[0061] (3) Add 60g of polyethylene succinate to 0.8L of N,N-dimethylformamide, stir and then add 12g of acrylonitrile. Stir at 30℃ for 12h, remove N,N-dimethylformamide by vacuum distillation, wash the product with methanol, and dry to obtain polyethylene succinate.

[0062] (3) Add 800g of nitrile rubber to a two-roll mill for plasticizing, then add 60g of zinc oxide, 12g of stearic acid and 9g of antioxidant RD for mixing, and sheet out to obtain nitrile rubber compound.

[0063] (4) Mix 200g polylactic acid, 10g dioctyl phthalate and 50g polyethylene succinate, add them to a two-roll mill, plasticize at 160℃, then add nitrile rubber compound, mix, and finally add 16g dicumyl peroxide and 10g accelerator TMTD, vulcanize for 8min, and sheet to obtain biodegradable nitrile rubber.

[0064] Nitrile rubber was placed in a flat vulcanizing machine and hot-pressed at 165℃ and 10MPa for 5 minutes, followed by cold pressing for 8 minutes to prepare the test specimens. Tensile properties were tested according to standard GB / T 528-2009, and tear strength was tested according to standard GB / T 529-2008. Degradability was tested according to standard GB / T 19277.1-2011 over a period of 30 days.

[0065] Table 1 Properties of Nitrile Rubber

[0066]

[0067] Tests showed that the nitrile rubber in Comparative Example 1 had low tensile and tear strength, and poor mechanical properties. This was mainly because polylactic acid and nitrile rubber have poor compatibility, which easily leads to interface defects and seriously affects the mechanical properties of the rubber-plastic composite material.

[0068] In Examples 1-3, cyanopolyester was incorporated into the polylactic acid-nitrile rubber materials. Its main chain contains polyester molecular chains similar to those of polylactic acid, while the side chains introduce a large number of cyano groups. These cyano groups have similar polarity to nitrile rubber, allowing the cyanopolyester to act as a compatibilizer, improving the compatibility between polylactic acid and nitrile rubber. The resulting rubber-plastic composite material exhibits better mechanical properties, with higher tensile strength and tear strength. Furthermore, the cyanopolyester's main chain contains a large number of biodegradable ester groups, and the hydroxyl groups in its side chains enhance the polyester's hydrophilicity, accelerating the hydrolysis of the ester groups and thus improving the biodegradability of the nitrile rubber material, making it more environmentally friendly.

[0069] The diglycidyl diacidate-diamine polymer in Comparative Example 2 does not contain cyano groups, making it difficult to improve the compatibility between polylactic acid and nitrile rubber, resulting in lower tensile properties and tear strength of the material.

[0070] The 1,4-butanediol diglycidyl ether of Comparative Example 3 and the cyano polymer prepared therefrom do not contain ester groups and polyester molecular chains, which makes it difficult to improve the compatibility between polylactic acid and nitrile rubber, resulting in low tensile properties and tear strength of the material, and low biodegradability of the nitrile rubber material.

[0071] The polyethylene succinate prepared in Comparative Example 4 does not contain imino groups and cannot undergo an addition reaction with acrylonitrile. Since no cyano groups are introduced into the side chain of polyethylene succinate, it is difficult to improve the compatibility between polylactic acid and nitrile rubber, resulting in lower tensile properties and tear strength of the material.

[0072] Although the invention has been described with reference to several typical embodiments, it should be understood that the terminology used is illustrative and exemplary, and not restrictive. Since the invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A degradable nitrile rubber, characterized by, The raw materials for the biodegradable nitrile rubber include 60-80 parts by weight of nitrile rubber, 3-6 parts by weight of filler, 0.5-1.2 parts by weight of activator, 0.6-1 parts by weight of antioxidant, 1.2-1.8 parts by weight of vulcanizing agent, 0.8-1.5 parts by weight of accelerator, 20-40 parts by weight of polylactic acid, 1-3 parts by weight of plasticizer, and 5-12 parts by weight of cyanopolyester; The method for preparing the cyanopolyester includes: adding diglycidyl diacidate-diamine polymer to N,N-dimethylformamide, stirring, adding acrylonitrile, reacting, washing the product by vacuum distillation, drying, and obtaining cyanopolyester.

2. The biodegradable nitrile rubber according to claim 1, characterized in that, The filler is zinc oxide, the activator is stearic acid, the vulcanizing agent is dicumyl peroxide, and the plasticizer is dioctyl phthalate.

3. The biodegradable nitrile rubber according to claim 1, characterized in that, The antioxidant is antioxidant D or antioxidant RD.

4. The biodegradable nitrile rubber according to claim 1, characterized in that, The accelerator is either TMTD or CZ.

5. The biodegradable nitrile rubber according to claim 1, characterized in that, The reaction temperature is 20-50℃, and the reaction time is 12-24h.

6. The biodegradable nitrile rubber according to claim 1, characterized in that, The amount of the diglycidyl diacidate-diamine polymer is 100 parts by weight, and the amount of acrylonitrile is 20-45 parts by weight.

7. The biodegradable nitrile rubber according to claim 6, characterized in that, The preparation method of the diacid diglycidyl ester-diamine polymer includes: adding 100 parts by weight of diacid diglycidyl ester and 26-38 parts by weight of diamine monomer to ethanol, heating to 70-80℃, stirring and refluxing for 18-24h, washing the product after vacuum distillation, and drying to obtain the diacid diglycidyl ester-diamine polymer.

8. The biodegradable nitrile rubber according to claim 6, characterized in that, The diacid diglycidyl ester is succinic acid diglycidyl ester or adipic acid diglycidyl ester; the molecular formula of the diamine monomer is NH2-(CH2) n -NH2, n is any one of 2-10.

9. A method for preparing biodegradable nitrile rubber as described in any one of claims 1-8, characterized in that, The preparation method includes: (1) Add nitrile rubber to a two-roll mill for plasticizing, then add filler, activator and antioxidant for mixing, and sheet out to obtain nitrile rubber compound; (2) Mix polylactic acid, plasticizer and cyanopolyester, add to open mill, plasticize at 160-170℃, then add nitrile rubber compound, mix, and finally add vulcanizing agent and accelerator, vulcanize for 4-8 minutes, and sheet to obtain degradable nitrile rubber.

10. The application of a biodegradable nitrile rubber obtained by the preparation method as described in claim 9 in gloves.

Images