Water-based release agent for producing disposable butyronitrile gloves, preparation method of water-based release agent and demolding method of butyronitrile gloves

Abstract

The invention provides a water-based release agent for producing disposable butyronitrile gloves, a preparation method of the water-based release agent and a demolding method of the butyronitrile gloves, and belongs to the technical field of release agents. The water-based release agent is prepared from the following components in percentage by weight: 6 to 10 percent of hydrophobic nano silicon dioxide, 1 to 4 percent of organic silicon microspheres, 1 to 1.5 percent of a nonionic surfactant, 1 to 2 percent of an anionic surfactant, 8 to 15 percent of a coalescing agent, 0.4 to 0.6 percent of a pH regulator, 0.08 to 0.12 percent of a de-foaming agent, 0.08 to 0.1 percent of a preservative and 68 to 80 percent of water. Through a compounding technology of hydrophobic nano silicon dioxide and organic silicon microspheres, and by combining a special microstructure formed in a water-based carrier, the water-based release agent disclosed by the invention has excellent release performance, stability and film forming uniformity, and residues of the water-based release agent have no adverse effect on subsequent surface treatment of butyronitrile gloves.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of release agent, in particular to a water-based release agent for producing disposable nitrile glove, a preparation method thereof and a release method of nitrile glove. BACKGROUND

[0002] In the production process of disposable nitrile glove, in order to peel the vulcanized glove from the ceramic hand mold smoothly, a layer of release agent must be coated on the hand mold before dipping the latex. The current release agent is mainly calcium stearate system, although the release effect is acceptable, but it has the following significant shortcomings: 1. It mainly depends on the "flaky" or "powdery" physical particles of calcium stearate, a physical isolation layer is formed on the surface of the mold. Its lubrication mechanism is sliding friction, the friction coefficient is relatively high and unstable, and local friction force is easy to be too large due to uneven distribution of particles.

[0003] 2. Calcium stearate is very easy to scale on high-temperature mold. These scale layers are hard and difficult to clean, which causes the production line to be shut down frequently for chemical or physical cleaning, seriously affecting the production efficiency.

[0004] 3. The powdery residues of calcium stearate system will inevitably transfer to the surface of nitrile glove. These hydrophobic powder residues will seriously interfere with the subsequent chlorination or polyurethane (PU) coating process, resulting in poor adhesion of coating, uneven surface treatment, or pinholes, affecting the yield.

[0005] Therefore, it is urgent to develop a water-based release agent with high efficiency, less residue and good compatibility with subsequent processing technology to meet the production needs of high-quality disposable nitrile glove. SUMMARY

[0006] Therefore, the purpose of the present application is to provide a water-based release agent for producing disposable nitrile glove, a preparation method thereof and a release method of nitrile glove. The water-based release agent provided by the present application has excellent release performance, stability and film uniformity, and its residues have no adverse effect on the subsequent surface treatment of nitrile glove.

[0007] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions: The present application provides a water-based release agent for producing disposable nitrile glove, which comprises the following components in the following amounts: Hydrophobic nano-silica 6~10wt%, silicone microspheres 1~4wt%, non-ionic surfactant 1~1.5wt%, anionic surfactant 1~2wt%, film-forming aid 8~15wt%, pH adjuster 0.4~0.6wt%, defoaming agent 0.08~0.12%, preservative 0.08~0.1%, water 68~80wt%.

[0008] Preferably, the hydrophobic nanosilica has a particle size of 10-40 nm and a specific surface area of 200-400 m 2 / g.

[0009] Preferably, the silicone microspheres have a diameter of 1-5 μm and a contact angle > 110°.

[0010] Preferably, the silicone microspheres are made of polydimethylsiloxane.

[0011] Preferably, the film-forming aid comprises modified acrylate, which comprises anionic silicone-modified acrylic emulsion and polyurethane acrylate copolymer emulsion.

[0012] Preferably, the mass ratio of the anionic silicone-modified acrylic emulsion and the polyurethane acrylate copolymer emulsion is (7:3) to (5:5).

[0013] Preferably, the pH regulator comprises one or more of 2-amino-2-methyl-1-propanol (AMP-95), N,N dimethyl ethanolamine and triethanolamine.

[0014] The present application also provides a preparation method of the aqueous release agent described in the above technical solution, comprising the following steps: adding non-ionic surfactant, anionic surfactant, pH regulator, defoaming agent and preservative into part of the water in sequence to obtain a pre-dispersion; adding hydrophobic nanosilica and silicone microspheres into the pre-dispersion to obtain a slurry; adding film-forming aid and the remaining water into the slurry in sequence to obtain the aqueous release agent.

[0015] The present application also provides a release method of nitrile glove, comprising the following steps: sequentially performing cleaning of hand mold, dipping of release agent, dipping of coagulant, dipping of nitrile latex, dripping, lip rolling, vulcanization and chlorine aftertreatment, wherein the release agent is the aqueous release agent described in the above technical solution or the aqueous release agent prepared by the preparation method described in the above technical solution.

[0016] Preferably, the coagulant comprises calcium nitrate solution, and the concentration of the calcium nitrate solution is 10-15 wt%.

[0017] The application provides a water-based release agent for disposable nitrile glove production, which comprises the following components in the following contents: hydrophobic nanosilica 6-10 wt%, silicone microspheres 1-4 wt%, non-ionic surfactant 1-1.5 wt%, anionic surfactant 1-2 wt%, film-forming aid 8-15 wt%, pH adjuster 0.4-0.6 wt%, defoaming agent 0.08-0.12%, preservative 0.08-0.1%, and water 68-80 wt%.

[0018] Compared with the prior art, the application has the following beneficial effects: 1. Synergistic friction structure: through the composite technology of hydrophobic nanosilica and silicone microspheres, the hierarchical composite structure of "nanoparticle rolling layer" and "micron microsphere protruding island structure" is constructed by using the "ball bearing" effect of hydrophobic nanosilica and the "sliding hydrophobic" property of silicone microspheres. The synergistic effect of this structure is much greater than that of a single component. Combined with the method of forming a special microstructure in the water-based carrier, the friction coefficient in the glove production process is significantly reduced, the release efficiency is improved, and product defects are reduced.

[0019] 2. Excellent post-processing compatibility: the film-forming aid (including modified acrylate) is used to fix the lubricating particles (including hydrophobic nanosilica and silicone microspheres) on the mold surface, which greatly reduces the migration of active substances to the finished glove. The film formed during use can effectively improve the wetting state of the glove surface, avoiding the "mottling" or uneven coating phenomenon caused by the residue of the release agent during subsequent processing, and significantly improving the appearance quality of the finished product.

[0020] 3. Coating durability and mold protection: the film-forming aid combined with temperature-resistant silicone microspheres and hydrophobic nanosilica forms a protective film on the surface of the ceramic mold, which has good thermal stability and durability. This not only prolongs the effective release times of a single coating, but also reduces the direct erosion and fouling of the latex and chemicals on the ceramic mold, prolonging the service life of the mold.

[0021] 4. Quality improvement of finished gloves: uniform and extremely low friction coefficient ensures that the nitrile latex can be uniformly attached during the dipping process and uniformly stressed during demolding. This significantly reduces point defects, stretching deformation or mouth tearing caused by uneven demolding resistance, making the surface of the finished glove smoother and the defect rate lower (target not greater than 1%).

[0022] 5. Meet the environmental protection requirements.

[0023] The application further provides the preparation method of the water-based release agent for producing disposable nitrile gloves. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A schematic diagram of a microstructure formed by the water-based release agent on a mold surface. DETAILED DESCRIPTION

[0025] The application provides a water-based release agent for producing disposable nitrile gloves, which comprises the following components in the following amounts: hydrophobic nanosilica 6-10 wt%, silicone microspheres 1-4 wt%, non-ionic surfactant 1-1.5 wt%, anionic surfactant 1-2 wt%, film-forming aid 8-15 wt%, pH regulator 0.4-0.6 wt%, defoaming agent 0.08-0.12%, preservative 0.08-0.1%, and water 68-80 wt%.

[0026] In the application, the raw materials used are commercially available products in the art, unless otherwise specified.

[0027] In the application, the content of the hydrophobic nanosilica in the water-based release agent can be specifically 6 wt%, 8 wt% or 10 wt%. The hydrophobic nanosilica exhibits significant advantages as a lubricant additive in reducing friction and wear. The hydrophobic nanosilica can generate both rolling friction and sliding friction at the friction interface, form a protective film to reduce friction, and tend to fill surface pits, so that the friction surface becomes smooth, thereby reducing the friction coefficient.

[0028] In the application, the particle size of the hydrophobic nanosilica is preferably 10-40 nm, and can be specifically 10 nm, 20 nm, 30 nm or 40 nm. The specific surface area is preferably 200-400 m 2 / g, and can be specifically 200 m 2 / g, 300 m / g or 400 m / g.

[0029] In specific embodiments of the present application, the hydrophobic nanosilica is preferably HB-630 from Hubei HuiFu Nanometer Material Co., Ltd., SS-S50K from Wuhu JiXin New Material Technology Co., Ltd., or VK-SP30S from Xuancheng Jingrui New Material Co., Ltd.

[0030] In the present application, the content of the silicone microspheres in the aqueous release agent can be specifically 1wt%, 2wt%, 3wt% or 4wt%, the present application applies the hydrophobic nanosilica and silicone microspheres compounding technology to the field of glove release agent, by forming a special microstructure in the aqueous carrier, the friction coefficient is significantly reduced, the hydrophobic nanosilica has excellent thermal stability and chemical stability, while the silicone microspheres provide good hydrophobic performance, the combination of the two can form a composite material with hierarchical structure, and better release effect is achieved.

[0031] In the present application, the diameter of the silicone microspheres is preferably 1-5μm, and can be specifically 1, 2, 3, 4 or 5μm, and the contact angle is preferably >110°.

[0032] In the present application, the material of the silicone microspheres is preferably polydimethylsiloxane.

[0033] In the present application, the silicone microspheres are preferably resistant to temperatures ≥150℃.

[0034] In specific embodiments of the present application, the silicone microspheres are preferably KMP-590 from ShinEtsu, HY-690 from Shenzhen Haiyang Powder Technology Co., Ltd., or ETERPEARL GP3500 from Changxing Material Industrial Co., Ltd.

[0035] In the present application, the content of the non-ionic surfactant in the aqueous release agent can be specifically 1wt%, 1.2wt% or 1.5wt%.

[0036] In the present application, the non-ionic surfactant is preferably a fatty alcohol polyoxyethylene ether or a polyoxyethylene castor oil derivative, and in specific embodiments of the present application, it is preferably Haishihua MOA-9 or Haishihua EL-30 from Haian Petroleum Chemical Plant in Jiangsu Province.

[0037] In the present application, the content of the anionic surfactant in the aqueous release agent can be specifically 1wt%, 1.5wt%, 1.8wt% or 2wt%.

[0038] In the present application, the anionic surfactant is preferably sodium fatty alcohol polyoxyethylene ether sulfate (AES) or sodium dodecyl sulfate (SDS).

[0039] In the present application, the content of the film-forming aid in the aqueous release agent can be specifically 10wt%, 12wt% or 15wt%.

[0040] In the present application, the film-forming aid includes preferably modified acrylate, which preferably includes anionic silicone-modified acrylic emulsion and polyurethane acrylic copolymer emulsion.

[0041] In the present application, the mass ratio of the anionic silicone-modified acrylic emulsion and the polyurethane acrylic copolymer emulsion is preferably (7:3)~(5:5), and can be specifically 7:3, 6:4 or 5:5.

[0042] In the present application, the Tg of the film-forming aid is preferably 10~45℃, and can be specifically 10, 20, 30, 40 or 45℃.

[0043] In specific embodiments of the present application, the anionic silicone-modified acrylic emulsion is preferably Bemis TX-010 of Dow Chemical (China) Co., Ltd. or LNS-2573 of Qingdao Enze Chemical Co., Ltd.; and the polyurethane acrylic copolymer emulsion is preferably Lacper 4220 of Wanhua Chemical Group Co., Ltd. or PUA-5811 of Guangzhou Guanzhi New Material Technology Co., Ltd.

[0044] In the present application, the content of the pH regulator in the aqueous release agent can be specifically 0.4wt%, 0.5wt% or 0.6wt%.

[0045] In the present application, the pH regulator preferably includes one or more of 2-amino-2-methyl-1-propanol (AMP-95), N,N dimethyl ethanolamine and triethanolamine.

[0046] In the present application, the content of the defoaming agent in the aqueous release agent can be specifically 0.08wt%, 0.1wt% or 0.12wt%.

[0047] In specific embodiments of the present application, the defoaming agent is preferably a silicone-based defoaming agent, and more preferably TEGO Airex 902W of Evonik Special Chemicals (Shanghai) Co., Ltd., TSA-630 of Jiangsu Tenda Additives Co., Ltd. or SAG-630A of Jiangsu Sixin Technology Application Research Institute Co., Ltd.

[0048] In the present application, the content of the preservative in the aqueous release agent can be specifically 0.081wt%, 0.09wt% or 0.1wt%.

[0049] In the present application, the preservative is preferably a mixture of 2-methyl-4-isothiazolin-3-one (MIT) and 1,2-benzisothiazolin-3-one (BIT), more preferably Defros BM or Defros BM2550 of Hofmann (Tianjin) Chemical Co., Ltd.

[0050] In the present application, the water is preferably deionized water.

[0051] In the present application, the solid content of the aqueous release agent is preferably 22-30%, and the pH value is preferably 8.5-9.5.

[0052] In the present application, the aqueous release agent is based on the principle of nanoparticle surface effect and microstructure contact area reduction, and the hydrophobic nanosilica particles have high specific surface area and surface activity, which can form a uniform dispersed micro "ball bearing" effect on the surface of the glove mold; the silicone microspheres provide good sliding performance and hydrophobic properties, and after compounding, a special hierarchical structure is formed in the aqueous carrier: Nanoparticle rolling effect: hydrophobic nanosilica forms a rolling layer at the interface, which converts sliding friction into rolling friction, and the theoretical calculation of the friction coefficient is formula (1): Formula (1); Where μ0 is the friction coefficient without nanoparticles (0.4), η is the nanoparticle coverage (target > 80%), r is the radius of hydrophobic nanosilica (5-20 nm), and R is the contact deformation radius (500 nm).

[0053] Contact area reduction principle: microstructure reduces the actual contact area, according to the Hertz contact theory, the friction force F is proportional to the actual contact area A, as shown in formula (2): Formula (2); Where τ is the interfacial shear strength, and through microstructure design, the actual contact area (the sum of the effective contact sections of the micro convex structure (mainly microspheres) of the nitrile latex film and the aqueous release agent) can be reduced by 65-75%.

[0054] The microstructure design of the aqueous release agent formed on the surface of the mold is shown in Figure 1 , including: Bottom structure: the hydrophobic nanosilica adsorbed on the surface of the ceramic substrate forms a uniformly distributed base layer, i.e. the nanoparticle rolling layer, with a thickness of 50-80 nm and a coverage of > 85%; The middle layer structure: the organic silicon microspheres are embedded in and protrude from the nanoparticle layer, forming a "micron microsphere protruding island structure", the diameter of the organic silicon microspheres is preferably 1-5 μm, the average spacing is 8-12 μm, the average spacing refers to the average center distance between the organic silicon microspheres, and the average spacing ensures that the nitrile latex film forms a multi-point contact at the top of the microspheres, avoiding the collapse of the latex film to contact the bottom nanolayer; The surface layer structure: the film-forming aid forms a translucent network structure, that is, a film-forming aid layer, which "fixes" the lubricating particles (hydrophobic nanosilica and organic silicon microspheres) on the surface of the mold. The non-ionic surfactant and the anionic surfactant are distributed on the interfaces of the particles and the surface of the coating, and are mainly enriched on the surface of the film or wrapped by the polymer matrix after film formation.

[0055] In the present application, the key size parameters of the microstructure preferably include: Nanoparticle layer thickness: 50-80 nm; Organic silicon microsphere protrusion height: 1.5-2.0 μm; Surface roughness Ra: 0.3-0.5 μm; Contact angle: 110-120°: The present application significantly reduces the friction coefficient in the glove production process, improves the demolding efficiency, reduces product defects, meets environmental protection requirements and cost control targets, and achieves the following targets: reducing the friction coefficient to 0.15 or less, improving the demolding efficiency by 30% or more, reducing the glove surface defect rate to 1% or less, while ensuring environmental protection and economic feasibility.

[0056] The present application also provides a preparation method of the water-based release agent described in the above technical solution, comprising the following steps: The non-ionic surfactant, the anionic surfactant, the pH adjuster, the defoaming agent and the preservative are sequentially added to part of the water to obtain a pre-dispersion liquid; The hydrophobic nanosilica and the organic silicon microspheres are added to the pre-dispersion liquid to obtain a slurry; The film-forming aid and the remaining water are sequentially added to the slurry to obtain the water-based release agent.

[0057] The non-ionic surfactant, the anionic surfactant, the pH adjuster, the defoaming agent and the preservative are sequentially added to part of the water to obtain a pre-dispersion liquid.

[0058] In the present application, the part of the water preferably accounts for 70% of the total weight of the water.

[0059] In the present application, the non-ionic surfactant, the anionic surfactant, the pH regulator, the defoaming agent and the preservative are sequentially added under stirring.

[0060] In the present application, the stirring speed is preferably 100-200 rpm.

[0061] After the addition is completed, the stirring is preferably continued for 10 min to completely dissolve and uniformly mix.

[0062] After the pre-dispersion is obtained, hydrophobic nano-silica and silicone microspheres are added to the pre-dispersion to obtain a slurry.

[0063] In the present application, the hydrophobic nano-silica and the silicone microspheres are preferably added at a speed of 1000-1500 rpm.

[0064] After the addition is completed, the stirring is preferably continued for 20-30 min to ensure that the powder is completely wetted and not aggregated.

[0065] After the slurry is obtained, film-forming aids and the remaining water are sequentially added to the slurry to obtain the water-based release agent.

[0066] In the present application, the film-forming aids are preferably added at a speed of 300-500 rpm, and then the stirring is continued for 15 min, the remaining water is added, and the stirring is continued at a speed of 300-500 rpm for 10 min to obtain the water-based release agent.

[0067] After the stirring is completed, the solid content (preferably 22-30%) and the pH value (preferably 8.5-9.5) are preferably detected to be qualified, and then the product is filtered to obtain the water-based release agent.

[0068] The reasons for the stepwise addition in the preparation method of the present application are as follows: Powder wetting difficulty: the hydrophobic nano-silica and the silicone microspheres have strong hydrophobicity and large specific surface area, and if they are directly added into a system containing film-forming aids and emulsifiers, the powder will easily snatch the emulsifiers in the system, resulting in emulsion demulsification, skinning or gel particle formation.

[0069] Anti-aggregation: the powder must be completely depolymerized, wetted and uniformly dispersed in the aqueous phase containing surfactants (non-ionic surfactants and anionic surfactants) by using high shear force to form a stable slurry.

[0070] Protection of emulsion: the film-forming aids are sensitive to high shear force, and if they are added in the high-speed dispersion stage, demulsification will easily occur, resulting in mechanical stability problems. Therefore, the film-forming aids must be added after the powder is dispersed well and the speed is reduced.

[0071] The present application also provides a release method for butyronitrile gloves, comprising the following steps: After sequentially performing cleaning of the hand mold, immersion of a release agent, immersion of a coagulant, immersion of a nitrile latex, leaching, lip rolling, vulcanization, and chlorine washing post-processing, the release agent is the aqueous release agent described in the above technical solution or the aqueous release agent prepared by the preparation method described in the above technical solution.

[0072] In the present application, the hand mold is preferably a ceramic mold.

[0073] In the present application, the coagulant preferably comprises a calcium nitrate solution, and the concentration of the calcium nitrate solution is preferably 10-15 wt%, and can be specifically 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, or 15 wt%.

[0074] In the present application, the vulcanization is preferably hot air vulcanization, and the temperature of the hot air vulcanization is 120℃, and the time is 20 min.

[0075] In the present application, the active chlorine concentration of the chlorine washing post-processing is preferably 400-800 ppm, and can be specifically 400, 600, or 800 ppm, the pH value is preferably 2.0-3.0, and the processing time is preferably 1-2 min. After the chlorine washing post-processing is completed, it is preferably further comprising sequentially performing neutralization and water washing to remove the powder on the surface of the glove and reduce the stickiness of the latex itself.

[0076] The aqueous release agent provided by the present application uses water as a dispersion medium, is environmentally friendly and safe, and through the composite technology of hydrophobic nano-silica and organic silicon microspheres, combined with the formation of a special microstructure in the aqueous carrier, the aqueous release agent of the present application has excellent release performance, stability, and film uniformity, and the residue has no adverse effect on the subsequent surface treatment (such as PU coating, chlorination) of the nitrile glove.

[0077] The technical solutions in the present application will be clearly and completely described below in combination with the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0078] Example 1 Water-based release agent formulation: 8wt% hydrophobic nano silica (HB-630), 3wt% organosilicon microspheres (KMP-590), 1.2wt% nonionic surfactant (MOA-9), 1.5wt% anionic surfactant (AES), 12wt% film-forming aid (a mixture of LNS-2573 and Lacper 4220 in a 7:3 mass ratio), 0.5wt% pH adjuster (AMP-95), 0.1wt% defoamer (TSA-630), 0.1% preservative (Defros BM), and 73.6wt% deionized water.

[0079] The preparation method is as follows: Pre-dispersion: Add water (70% of the total mass of the formulation) to a mixing tank and start stirring (200 rpm). Add nonionic surfactant, anionic surfactant, pH adjuster, defoamer, and preservative in sequence, and stir for 10 minutes until completely dissolved and mixed.

[0080] Slurry preparation: Hydrophobic nano-silica and organosilicon microspheres were added to a high-speed disperser (1000 rpm) and dispersed for 20 min to obtain a slurry.

[0081] Add film-forming aid: Reduce stirring speed (500 rpm), add film-forming aid, and continue stirring for 15 minutes.

[0082] Blending: Add the remaining water, stir at 500 rpm for 10 minutes, and after the solid content and pH value are qualified, filter and discharge.

[0083] Example 2 Water-based release agent formulation: 6wt% hydrophobic nano silica (VK-SP30S), 4wt% organosilicon microspheres (ETERPEARLGP3500), 1.0wt% nonionic surfactant (EL-30), 2.0wt% anionic surfactant (SDS), 10wt% film-forming aid (TX-010 and PUA-5811 mixed in a 5:5 mass ratio), 0.6wt% pH adjuster (triethanolamine), 0.1wt% defoamer (SAG-630A), 0.1wt% preservative (Defros BM), and 76.2wt% deionized water.

[0084] The preparation method is the same as in Example 1.

[0085] Example 3 Water-based release agent formulation: 10wt% hydrophobic nano silica (SS-S50K), 3wt% organosilicon microspheres (HY-690), 1.5wt% nonionic surfactant (MOA-9), 1.8wt% anionic surfactant (AES), 15wt% film-forming aid (a mixture of LNS-2573 and PUA-5811 in a 6:4 mass ratio), 0.5wt% pH adjuster (AMP-95), 0.1wt% defoamer (SAG-630A), 0.1wt% preservative (Defros BM2550), and 68wt% deionized water.

[0086] The preparation method is the same as in Example 1.

[0087] Comparative Example 1 MaxCo B101 calcium stearate release agent, commercially available from Lexis Chemical Sdn Bhd in Malaysia.

[0088] Comparative Example 2 Release agent formulation: 10wt% hydrophobic nano silica (SS-S50K), 1.5wt% nonionic surfactant (MOA-9), 1.8wt% anionic surfactant (AES), 15wt% film-forming aid (a mixture of LNS-2573 and PUA-5811 in a 6:4 mass ratio), 0.5wt% pH adjuster (AMP-95), 0.1wt% defoamer (SAG-630A), 0.1wt% preservative (Defros BM2550), and 71wt% deionized water.

[0089] The preparation method is similar to that in Example 1, except that the types and amounts of raw materials are different.

[0090] Comparative Example 3 Release agent formulation: 6wt% silicone microspheres (HY-690), 1.5wt% nonionic surfactant (MOA-9), 1.8wt% anionic surfactant (AES), 15wt% film-forming aid (a mixture of LNS-2573 and PUA-5811 in a 6:4 mass ratio), 0.5wt% pH adjuster (AMP-95), 0.1wt% defoamer (SAG-630A), 0.1wt% preservative (Defros BM2550), and 75wt% deionized water.

[0091] The preparation method is similar to that in Example 1, except that the types and amounts of raw materials are different.

[0092] Application process: The application processes of Examples 1-3 and Comparative Examples 2-3 are as follows: Cleaning the hand mold → Impregnation with release agent → Impregnation with coagulant → Impregnation with matured nitrile latex → Lamination → Lid rolling → Vulcanization → Chlorine washing and post-treatment → Demolding inspection Coagulant formulation: calcium nitrate solution, concentration 13wt%.

[0093] Vulcanization: Hot air vulcanization, 120℃, 20min.

[0094] Post-chlorination treatment: active chlorine concentration 800ppm, pH 3.0, treatment time 2 minutes, followed by neutralization and water washing.

[0095] The application process for Comparative Example 1 is as follows: Cleaning the hand mold → Impregnation with coagulant (containing calcium stearate release agent) → Impregnation with matured nitrile latex → Lapping → Lid rolling → Vulcanization → Chlorine washing and post-treatment → Demolding inspection Coagulant formula: 15wt% calcium nitrate, 1.5wt% calcium stearate release agent, water balance.

[0096] Vulcanization: Hot air vulcanization, 120℃, 20min.

[0097] Post-chlorination treatment: active chlorine concentration 800ppm, pH 3.0, treatment time 2 minutes, followed by neutralization and water washing.

[0098] Performance testing methods are as follows: 1. Coefficient of friction: The coefficient of friction of nitrile rubber sheets was tested using an FPT-F1 friction coefficient tester in accordance with GB / T 10006-2021 standard.

[0099] 2. Demolding efficiency: On the pilot production line, the number of gloves successfully demolded per unit time (1 hour) was counted and compared with the production line using standard calcium stearate release agent to calculate the percentage increase in efficiency.

[0100] 3. Defect rate: Randomly select 500 gloves and check for defects such as tearing, holes, adhesion, and powdering caused by demolding, and calculate the defect rate.

[0101] 4. Post-processing compatibility: Visually inspect whether the surface of the chlorinated gloves is flat and uniform, and count whether there are "shrinkage holes", "mottling" or areas with poor wetting.

[0102] The performance test results are shown in Table 1. Result analysis: Examples 1-3 all significantly improved the production and finished product performance of nitrile gloves, with Example 3 exhibiting the best overall performance. Comparative Example 1, used as a baseline, exposed the main shortcomings of the prior art: high coefficient of friction, easy scaling with the mold after drying, leading to time-consuming and laborious mold cleaning, and a high defect rate in the gloves; simultaneously, its residue can interfere with subsequent processing, causing defects such as mottling. Comparative Examples 2 and 3 further demonstrate the synergistic effect between hydrophobic nano-silica and organosilicon microspheres. That is, the water-based release agent of this invention is significantly superior to the mainstream calcium stearate system in terms of coefficient of friction, yield, and post-processing appearance quality.

[0103] Table 1 Performance Test Results

[0104] Further durability tests were conducted on the performance of the water-based release agent in protecting ceramic molds and reducing scaling. The results are shown in Table 2.

[0105] Test method: 1. Effective demolding times per coating: Under laboratory simulation conditions, after applying a release agent to the hand mold once and drying it, the nitrile latex is continuously impregnated and demolded. The cumulative number of demolding times is recorded until sticking or demolding difficulties occur (significant increase in tensile force).

[0106] 2. Mold scaling rate (simulation): Clean ceramic sheets were immersed in a release agent, dried, and aged at 120℃. This process was repeated 100 times, and the weight gain per unit area of ​​the ceramic sheet (mg / cm²) was measured. 2 This simulates scaling conditions during long-term production.

[0107] 3. Production line cleaning cycle: On the pilot production line, the continuous running time (in days) from the time the mold is thoroughly cleaned to the time it needs to be cleaned again due to severe buildup of dirt is recorded.

[0108] Table 2 Test Results of Mold Protection and Scale Resistance

[0109] As shown in Table 2, Example 3 exhibits the best mold protection performance. This is due to the protective film layer structure formed by the organosilicon microspheres and hydrophobic nano-silica. After a single coating, it can be continuously demolded up to 10 times, far exceeding the single-coat requirement of traditional calcium stearate. At the same time, the extremely low scaling and weight gain (far lower than Comparative Example 1) proves that this formulation can significantly reduce chemical deposition on the mold surface, extending the mold cleaning cycle on the production line from the traditional 2-3 days to 20 days, greatly improving production efficiency and extending the service life of ceramic molds.

[0110] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A water-based release agent for the production of disposable nitrile gloves, characterized in that, Components including the following contents: Hydrophobic nano-silica 6~10wt%, organosilicon microspheres 1~4wt%, nonionic surfactant 1~1.5wt%, anionic surfactant 1~2wt%, film-forming aid 8~15wt%, pH adjuster 0.4~0.6wt%, defoamer 0.08~0.12%, preservative 0.08~0.1%, water 68~80wt%.

2. The water-based release agent according to claim 1, characterized in that, The hydrophobic nano-silica has a particle size of 10-40 nm and a specific surface area of ​​200-400 m². 2 / g.

3. The water-based release agent according to claim 1, characterized in that, The diameter of the organosilicon microspheres is 1~5μm, and the contact angle is >110°.

4. The water-based release agent according to claim 1 or 3, characterized in that, The organosilicon microspheres are made of polydimethylsiloxane.

5. The water-based release agent according to claim 1, characterized in that, The film-forming aid includes modified acrylates, which include anionic silicone-modified acrylic emulsions and polyurethane acrylate copolymer emulsions.

6. The water-based release agent according to claim 5, characterized in that, The mass ratio of the anionic silicone-modified acrylic emulsion and the polyurethane acrylate copolymer emulsion is (7:3) to (5:5).

7. The water-based release agent according to claim 1, characterized in that, The pH adjuster includes one or more of 2-amino-2-methyl-1-propanol, N,N-dimethylethanolamine, and triethanolamine.

8. A method for preparing the water-based release agent according to any one of claims 1 to 7, characterized in that, Includes the following steps: A pre-dispersion solution was obtained by sequentially adding a nonionic surfactant, anionic surfactant, pH adjuster, defoamer, and preservative to a portion of water. Hydrophobic nano-silica and organosilicon microspheres were added to the pre-dispersion liquid to obtain a slurry; Film-forming aid and remaining water are added sequentially to the slurry to obtain the water-based release agent.

9. A method for demolding nitrile gloves, characterized in that, Includes the following steps: The process involves sequentially cleaning the hand mold, impregnating with a release agent, impregnating with a coagulant, impregnating with nitrile latex, leaching, rolling the lip, vulcanizing, and chlorination post-treatment. The release agent is the water-based release agent according to any one of claims 1 to 7 or the water-based release agent prepared by the preparation method according to claim 8.

10. The demolding method according to claim 9, characterized in that, The coagulant includes a calcium nitrate solution with a concentration of 10-15 wt%.

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