A nitrile latex composite material, its preparation method and application

Abstract

The present invention discloses a nitrile latex composite material, a preparation method and an application thereof, relating to the technical field of nitrile latex. The nitrile latex composite material of the present invention comprises the following components in parts by weight: 100 parts of nitrile latex, 0.1 to 1 part of an anionic surfactant, 0.5 to 3 parts of an alkaline stabilizer, 1 to 8 parts of a resin crosslinking agent, 0.2 to 1 part of an antioxidant, 0 to 1.5 parts of an activator, and 0 to 1.5 parts of a catalyst. The nitrile latex composite material prepared by the above formula is non-toxic, harmless and odorless, and can be prepared under mild conditions. The nitrile gloves prepared from the nitrile latex have good aging resistance, can be worn for a long time without damage, have a high elongation rate and good softness.

Description

Technical Field

[0001] The present invention relates to the technical field of nitrile latex, and particularly to a nitrile latex composite material, a preparation method thereof, and an application thereof. Background Art

[0002] In order to meet normal use conditions, including mechanical properties, aging properties, and wearing properties, it is generally necessary to add sulfur and various accelerators to the nitrile latex formulation to crosslink rubber molecules into a network structure, enabling the product to have excellent properties; if sulfur and accelerators are missing in the formulation, or if one of them is missing, it is very difficult to process and form; even if a finished product is produced, due to the easy breakage, poor durability, and poor mechanical properties of the finished product, its practicality is relatively low.

[0003] Sulfur belongs to the fourth category of dangerous chemicals, and it has certain cytotoxicity both during the production process and in the finished product, causing human allergies, and there is also a risk of inducing various diseases after long-term contact; moreover, the existing conventional sulfur vulcanization system requires post-vulcanization at a relatively high temperature (100 - 120 °C), resulting in high energy consumption.

[0004] The nitrile latex products obtained by the existing conventional vulcanization system generally have a relatively low elongation at break. If the elongation at break is increased by adjusting the formulation ratio, problems will occur in the strength or durability of the product.

[0005] Patent CN202111078278.7, a sulfur-free vulcanized carboxylated nitrile latex and its vulcanization method and application, also discloses a preparation method of sulfur-free carboxylated nitrile latex, which uses peroxide vulcanization to prepare the carboxylated nitrile latex, but adding peroxide will affect the stability of the carboxylated nitrile latex and the elongation at break of the product. Summary of the Invention

[0006] The purpose of the present invention is to provide a nitrile latex composite material, a preparation method thereof, and an application thereof, so as to solve the technical problems that the preparation conditions of the existing nitrile latex composite material are harsh, the energy consumption is high, and it is difficult to balance mechanical properties and durability.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is: a nitrile latex composite material, the nitrile latex composite material contains the following components in parts by weight: 100 parts of nitrile latex, 0.1 - 1 part of an anionic surfactant, 0.5 - 3 parts of an alkaline stabilizer, 1 - 8 parts of a resin crosslinking agent, 0.2 - 1 part of an antioxidant, 0 - 1.5 parts of an activator, and 0 - 1.5 parts of a catalyst.

[0008] The present invention discovers through experiments that, compared with the conventional sulfur vulcanization system, using resin as a crosslinking agent can vulcanize the nitrile latex composite material under milder conditions with low energy consumption, and the products prepared from the nitrile latex composite material have good mechanical properties and durability.

[0009] Preferably, the nitrile latex composite material comprises the following components in parts by weight: 100 parts of nitrile latex, 0.2 - 0.6 part of anionic surfactant, 1.5 - 2 parts of basic stabilizer, 1.5 - 4 parts of resin crosslinking agent, 0.3 - 0.6 part of antioxidant, 0.3 - 1 part of activator, and 0.5 - 1.5 parts of catalyst.

[0010] The above limitations on the amounts of the anionic surfactant and the basic stabilizer are to maintain the stability of the system, avoid local coagulation during the production process, and have a great impact on the processing performance. Adding an activator is to improve the strength and modulus of the product. If the addition amount is too much, the modulus of the product will increase and the comfort will become worse. If the amount of the resin crosslinking agent is too small, the durability of the product will become worse. If the amount is too high, it will also affect the stability of the latex system and may cause problems such as an increase in the odor of the product. The catalyst will affect the speed of the vulcanization reaction between the resin and the nitrile latex. When the amount of the catalyst is less than 0.5 part, in addition to reducing the speed of the vulcanization reaction, it will also reduce the durability of the product prepared from the nitrile latex composite material. However, if the amount of the catalyst is too high, the stability of the system will become worse.

[0011] Preferably, the nitrile latex is carboxylated nitrile latex, and the surface tension of the nitrile latex is 30 - 60 Dyn / cm. The carboxylated nitrile latex has a relatively high bonding strength and mechanical properties superior to those of ordinary nitrile latex. When the surface tension of the nitrile latex meets the above limitations, the film-forming performance of the nitrile latex composite material is significantly better.

[0012] Preferably, the anionic surfactant is at least one of sodium dodecylbenzenesulfonate, alkyl diphenyl ether disulfonate, and dioctyl sulfosuccinate; the basic stabilizer is at least one of potassium hydroxide and ammonia monohydrate; the antioxidant is at least one of alkyl monophenol antioxidants and polymeric alkyl polyphenol antioxidants.

[0013] Preferably, the resin crosslinking agent is at least one of amino resin, vinyl resin, phenolic resin, and epoxy resin, and the amino resin is at least one of urea-formaldehyde resin, melamine-formaldehyde resin, and polyamide polyamine epichlorohydrin resin. Further preferably, the resin crosslinking agent is at least one of urea-formaldehyde resin, melamine-formaldehyde resin, and phenolic resin. Compared with other resin crosslinking agents, experiments find that the mechanical properties and durability of the products prepared by using the above three resin crosslinking agents are significantly more excellent.

[0014] Preferably, the active agent is at least one of metal oxides and carbonates; the catalyst is at least one of catalyst A and catalyst B; catalyst A is at least one of polyethyleneimine, aminomethane, diphenylethoxyphosphine, and ammonium sulfate, and catalyst B is at least one of sulfonic acid, sulfinic acid, and thiocarboxylic acid.

[0015] Preferably, the catalyst is a compound of catalyst A and catalyst B; the mass ratio of catalyst A to catalyst B is (1 - 3):(1 - 3). Selecting the above two catalysts in combination can improve the reaction degree and further improve the wearability and durability of the product.

[0016] Preferably, the active agent is at least one of zinc oxide, magnesium oxide, copper oxide, aluminum oxide, and zinc carbonate.

[0017] In addition, the present invention also discloses a preparation method of a nitrile latex composite material, and the preparation method includes the following steps:

[0018] (1) Dilute an anionic surfactant and an alkaline stabilizer with water respectively, and mix the diluted products with nitrile latex to obtain mixture A;

[0019] (2) Grind the active agent (if the weight part of the active agent is 0, it is not added) and an antioxidant into an aqueous dispersion, and mix the aqueous dispersion with the mixture A to obtain mixture B;

[0020] (3) Mix a resin crosslinking agent and a catalyst (if the weight part of the catalyst is 0, it is not added), dilute with water and then mix with the mixture B, stir, and pre-vulcanize to obtain the nitrile latex composite material.

[0021] Preferably, in step (1), the mass concentration of the anionic surfactant after dilution with water is 10% - 20%; when the alkaline stabilizer is potassium hydroxide, the mass concentration after dilution with water is 2% - 5%, and when the alkaline stabilizer is ammonia monohydrate, the mass concentration after dilution with water is 10% - 25%. The above limitation on the diluted concentration is to ensure the stability of the system.

[0022] Preferably, the D90 particle size of the active agent and the antioxidant in the aqueous dispersion is 3 - 8 μm. Excessive particle size will result in a smaller contact area between the active agent and the antioxidant and the latex particles, which is not conducive to their complete reaction in the latex, and too small particle size will make the dispersion difficult.

[0023] In addition, the present invention also discloses the application of the nitrile latex composite material in the preparation of nitrile gloves and the preparation method of the nitrile gloves, and the preparation method includes the following steps:

[0024] (1) Clean the hand mold with acid solution and alkali solution respectively, and then dry it;

[0025] (2) Immerse the hand mold obtained in step (1) in a coagulant, take it out and dry it.

[0026] (3) Immerse the hand mold obtained in step (2) in the nitrile latex composite material 1 - 2 times, take it out for shaping, hot water leaching, and curling, then vulcanize at 25 - 130 °C for 0.5 - 12 h, and finally perform chlorination treatment to obtain the nitrile gloves.

[0027] Preferably, in step (3), vulcanization is carried out at 60 - 100 °C.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The nitrile latex composite material prepared by the present invention using resin as a cross - linker can prepare products with good mechanical properties, especially high elongation and durability, without high - temperature vulcanization. The preparation process has low energy consumption and high economic benefits. Specific Embodiments

[0030] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0031] The components used in the examples and comparative examples are as follows:

[0032] Carboxylated nitrile latex: QD - 1001, ZXTD, surface tension is 31 Dyn / cm;

[0033] Nitrile latex: Model: 300, Taishan SanTree of Thailand, surface tension is 35 Dyn / cm;

[0034] Anionic surfactant: Sodium dodecylbenzenesulfonate, commercially available;

[0035] Alkaline stabilizer: Potassium hydroxide, commercially available;

[0036] Activator: Zinc oxide, commercially available;

[0037] Antioxidant: Polymerized alkyl polyphenol antioxidant, KY - 616, commercially available;

[0038] Resin cross - linker 1: Melamine - formaldehyde resin, REFORMCHEMICAL, brand: HK;

[0039] Resin cross - linker 2: Urea - formaldehyde resin, Jining Tangyi Chemical Co., Ltd., brand: 563;

[0040] Resin cross - linker 3: Phenolic resin, Sanshi Biology, brand: SH - 416156;

[0041] Resin crosslinking agent 4: Polyamide polyamine epichlorohydrin resin, manufactured by Ube Industries, Japan, grade: 1200;

[0042] Resin crosslinking agent 5: Vinyl resin, manufactured by Hebei Leon Anticorrosive Material Co., Ltd., LA - 066749;

[0043] Resin crosslinking agent 6: Epoxy resin, manufactured by Yueyang Petrochemical, E - 51;

[0044] Catalyst A: Methylamine, commercially available;

[0045] Catalyst B: Sulfonic acid, commercially available;

[0046] Sulfur: Commercially available;

[0047] Accelerator 1: Accelerator EZ, commercially available;

[0048] Accelerator 2: Accelerator BZ, commercially available;

[0049] Coagulant: Calcium nitrate, calcium chloride, commercially available;

[0050] The anionic surfactant, alkaline stabilizer, activator, antioxidant, sulfur, accelerators 1 - 2, and coagulant used in the examples and comparative examples are all the same commercially available products.

[0051] Examples 1 - 21

[0052] Examples of the nitrile rubber latex composite material of the present invention, the formulations of Examples 1 - 21 are shown in Table 1, and the preparation method is as follows:

[0053] (1) Dilute the anionic surfactant with water to a mass concentration of 15%, dilute the alkaline stabilizer with water to a mass concentration of 3%, mix the two, and then add them to the nitrile rubber latex or carboxylated nitrile rubber latex, and mix evenly to obtain mixture A;

[0054] (2) Grind the antioxidant and activator (if the weight part of the activator is 0, it is not added) into an aqueous dispersion with a ball mill. The D90 particle size of the activator and antioxidant in the aqueous dispersion is 3 - 8 μm, and add the aqueous dispersion to the mixture A to obtain mixture B;

[0055] (3) Mix the resin crosslinking agent and catalyst (if the weight part of the catalyst is 0, it is not added) evenly, dilute with 15 times the mass of water, and stir with a stirrer at a frequency of 50 Hz for 10 - 30 min until there are no lumpy particles in the solution to obtain mixture C;

[0056] (4) Dilute mixture B with water to a total solid content of 25%, add mixture C to it, stir with a stirrer at a frequency of 30 Hz, and pre - vulcanize at 25°C for 24 h to obtain the nitrile rubber latex composite material.

[0057] Table 1 (parts by weight)

[0058]

[0059]

[0060] Comparative Example 1

[0061] A nitrile latex composite material, whose formulation is shown in Table 2, is prepared as follows:

[0062] (1) Dilute the anionic surfactant with water to a mass concentration of 15%, dilute the alkaline stabilizer with water to a mass concentration of 3%, mix the two, and then add them to nitrile latex or carboxylated nitrile latex, mix evenly to obtain mixture A;

[0063] (2) Grind the antioxidant, activator, sulfur, and accelerator 1-2 into an aqueous dispersion with a ball mill. The D90 particle size of the solid particles in the aqueous dispersion is 3-8 μm, and add the aqueous dispersion to the mixture A to obtain mixture B;

[0064] (3) Dilute mixture B with water to a total solid content of 25%, stir at a frequency of 30 Hz, and pre-vulcanize at 25°C for 24 h to obtain the nitrile latex composite material.

[0065] Table 2 (parts by weight)

[0066]

[0067] Comparative Examples 2-3

[0068] Comparative Examples 2-3 are nitrile latex composite materials, and the only difference from Example 1 is the dosage of the resin crosslinking agent. The dosage of the resin crosslinking agent in Comparative Example 2 is 0.5 part, and the dosage of the resin crosslinking agent in Comparative Example 3 is 8.5 parts.

[0069] Application Examples 1-21 and Application Comparative Examples 1-3

[0070] Application Examples 1-21 are nitrile gloves prepared from the nitrile latex composite materials described in Examples 1-21 respectively, and Application Comparative Examples 1-3 are nitrile gloves prepared from the nitrile latex composite materials described in Comparative Examples 1-3 respectively. The preparation method of the nitrile gloves is as follows:

[0071] (1) Mix concentrated sulfuric acid with water respectively to make an acid solution with a mass concentration of 8%, and mix sodium hydroxide with sodium hypochlorite to make an alkali solution with an alkali mass concentration of 8%. Clean the hand mold. First, heat the prepared acid solution to 50 ± 5 °C, soak the hand mold for 10 s, take it out and rinse off the residual acid solution with clean water. Then soak it in the alkali solution heated to 50 ± 5 °C for 10 s, take it out again and rinse off the residual liquid, and brush it with a clean brush. After cleaning, put it in an oven at 80 °C and dry it for 10 min;

[0072] (2) Immerse the hand mold obtained in step (1) in a calcium nitrate solution with a calcium ion concentration of 13% for 10 s, take it out, and dry it in an oven at 80 °C for 5 min until the coagulant is completely dry. Then immerse it in the nitrile rubber latex composite material described in the example for 10 s, immerse it twice, and the two immersion times are the same. Then take it out, shape it in an oven at 60 °C for 2 min, then carry out hot water leaching and curling. Finally, put it in an oven and vulcanize it at 80 °C for 30 min. After vulcanization, place the glove in chlorine water with a chlorine concentration of 300 ppm for chlorination treatment for 1 min. After treatment, take it out and rinse off the residual chlorine water with clean water, and then dry the moisture on the glove surface and demold it to obtain the said nitrile glove.

[0073] Perform performance tests on Applications Example 1 - 21 and Application Comparative Examples 1 - 3, and refer to ASTM D6319 2019 for the test of mechanical properties;

[0074] Among them, the durability is evaluated through a wearing test. Wear it according to the size code that fits your palm. In this test, all the gloves manufactured in the examples and comparative examples are size M. The palm sizes of the test personnel are exactly suitable for the size of size M. Each application example and application comparative example are tested by the same 4 people (1 person wears 1 pair of gloves at the same time) and engage in the same food processing work. Among them, each application example and application comparative example wear and test a total of 16 (8 pairs) gloves, and each glove is worn for 5 h (the test ends if it is damaged during the wearing process), and record the breakage rate of the gloves after wearing for 3 h and 5 h. The test results are shown in Table 3:

[0075] Table 3

[0076]

[0077]

[0078] As can be seen from Table 3, the nitrile gloves described in Application Examples 1 to 21 did not break after being worn for 3 hours. The 300% modulus at elongation was 3.3 to 6.7 MPa, the elongation at break was 550% to 811%, the tensile strength was 21.5 to 42.8 MPa, and the tensile force was 9.0 to 18.3 N. The nitrile gloves had good mechanical properties and relatively good wearing comfort. The durability of Application Comparative Example 1 was poor, and breakage occurred after being worn for 3 hours. In Application Comparative Example 2, the amount of the resin crosslinking agent was too small, and the strength of the prepared nitrile gloves was too low, resulting in breakage after being worn for 3 hours. In Application Comparative Example 3, the content of the resin crosslinking agent was too high, the hardness of the nitrile gloves was too high, there were precipitates on the surface, the comfort was poor, and its elongation at break was relatively low, and the wearing durability was poor.

[0079] By comparing the formulations and test results of Application Examples 1 to 5, it can be found that when the raw materials of the nitrile latex composite material meet the following conditions, they have more excellent mechanical properties: 100 parts of nitrile latex, 0.2 to 0.6 parts of anionic surfactant, 1.5 to 2 parts of alkaline stabilizer, 0.3 to 1 part of activator, 1.5 to 4 parts of resin crosslinking agent, 0.5 to 1.5 parts of catalyst, and 0.3 to 0.6 parts of antioxidant. By comparing the formulations and test results of Application Example 1 and Application Example 6, it can be found that the nitrile gloves prepared with carboxylated nitrile latex have better comprehensive performance. By comparing the test results of Application Example 1, Application Examples 7 to 11, it can be found that the resin crosslinking agent is preferably melamine formaldehyde resin, urea formaldehyde resin, and phenolic resin. By comparing the formulations and test results of Application Example 1, Application Examples 12 to 17, it can be found that when the catalyst is a compound of Catalyst A and Catalyst B, the mechanical properties of the prepared nitrile gloves are better. Moreover, when the mass ratio of Catalyst A to Catalyst B is (1 to 3):(1 to 3), the durability of the nitrile gloves is excellent, and no breakage occurs after being worn for 5 hours. By comparing the performance test results of Application Example 2 and Application Examples 18 and 20, and Application Example 3 and Application Examples 19 and 21, it can be found that when the content of the catalyst or the activator is relatively small, the strength of the nitrile gloves is relatively low and the mechanical properties are slightly poor; when the content of the catalyst or the activator is relatively large, the 300% modulus at elongation of the nitrile gloves is relatively high and the comfort is poor.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention 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 invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A nitrile latex composite material, characterized in that, It comprises components in the following parts by weight: 100 parts of nitrile latex, 0.1 - 1 part of anionic surfactant, 0.5 - 3 parts of basic stabilizer, 1 - 8 parts of resin crosslinking agent, 0.2 - 1 part of antioxidant, 0.3 - 1.5 parts of activator, 0.5 - 1.5 parts of catalyst; The resin crosslinking agent is at least one of amino resin, vinyl resin, phenolic resin, and epoxy resin, and the amino resin is at least one of urea - formaldehyde resin, melamine - formaldehyde resin, and polyamide polyamine epichlorohydrin resin; The catalyst is a compound of catalyst A and catalyst B; the mass ratio of catalyst A to catalyst B is (1 - 3):(1 - 3); catalyst A is aminomethane, and catalyst B is sulfonic acid; The activator is at least one of metal oxides and carbonates.

2. The nitrile latex composite material according to claim 1, wherein It comprises components in the following parts by weight: 100 parts of nitrile latex, 0.2 - 0.6 part of anionic surfactant, 1.5 - 2 parts of basic stabilizer, 1.5 - 4 parts of resin crosslinking agent, 0.3 - 0.6 part of antioxidant, 0.3 - 1 part of activator, 0.5 - 1.5 parts of catalyst.

3. The nitrile latex composite material according to any one of claims 1 to 2, characterized in that The nitrile latex is carboxylated nitrile latex; the anionic surfactant is at least one of sodium dodecylbenzenesulfonate, alkyl diphenyl ether disulfonate, and dioctyl sulfosuccinate; the basic stabilizer is at least one of potassium hydroxide and ammonia monohydrate; the antioxidant is at least one of alkyl monophenol antioxidants and polymeric alkyl polyphenol antioxidants.

4. The nitrile latex composite material according to claim 3, characterized in that, The resin crosslinking agent is at least one of urea - formaldehyde resin, melamine - formaldehyde resin, and phenolic resin.

5. The nitrile latex composite material according to claim 1, characterized in that, The activator is at least one of zinc oxide, magnesium oxide, copper oxide, aluminum oxide, and zinc carbonate.

6. A preparation method of the nitrile latex composite material according to any one of claims 1 to 5, characterized in that, It includes the following steps: (1) Dilute the anionic surfactant and the basic stabilizer with water respectively, and mix the diluted products with the nitrile latex to obtain mixture A; (2) Grind the activator and the antioxidant into an aqueous dispersion, and mix the aqueous dispersion with mixture A to obtain mixture B; (3) Mix the resin crosslinking agent and the catalyst, dilute with water, and then mix with mixture B, stir, and pre - vulcanize to obtain the nitrile latex composite material.

7. The preparation method of the nitrile latex composite material according to claim 6, characterized in that, In the aqueous dispersion in step (two), the D90 particle size of the activator and the antioxidant is 3 - 8 μm.

8. Use of the nitrile latex composite material according to any one of claims 1 - 5 in the preparation of nitrile gloves.

9. A preparation method of nitrile gloves, characterized in that, It includes the following steps: (1) Clean the hand mold and dry it; (2) Immerse the hand mold obtained in step (1) in a coagulant, take it out and dry it; (3) Immerse the hand mold obtained in step (2) in the nitrile latex composite material according to any one of claims 1 - 5, take it out, shape, leach, and curl the edges, then vulcanize at 25 - 130 °C for 0.5 - 12 h, and finally perform chlorination treatment to obtain the nitrile gloves.

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