Process for obtaining and applying Anti-allergic and Anti-corrosive coating for metal accessories

Description

/ 12 “PROCESS FOR OBTAINING AND APPLYING ANTI-ALLERGIC AND ANTI-CORROSIVE COATING FOR METAL ACCESSORIES” Field of Invention [1] The present invention relates to the development of a coating for metal parts, accessories and utensils, for protection against corrosion and / or prevention of allergic reactions through skin contact with metals. The coating, after drying on the part, results in a thin, transparent film, providing a barrier between the metal surface and the skin. [2] The coating is formulated with the natural resin rosin and specific solvents, xylene and acetone, which ensure adhesive properties and form a protective film after drying. This coating meets a growing need for hypoallergenic solutions in the jewelry and accessories market, especially due to the high prevalence of allergies caused by metals such as nickel, copper and lead. In addition, the invention also protects against corrosion, extending the aesthetic and functional durability of the parts. [3] The coating process involves simple and efficient steps of controlled heating and agitation, enabling its uniform application through accessible methods such as brushes or sprays. Thus, the invention falls within the technical field of functional coating compositions for the jewelry and accessories industry, offering a sustainable, safe and practical alternative for both consumers and manufacturers. Description of the State of the Art [4] The invention in question falls within the field of functional coating compositions applied to metal accessories, focusing on solutions that prevent allergic reactions and corrosion. Metal allergy is a common condition, especially to nickel, copper and lead, frequently found in accessories such as earrings, necklaces, watches and eyeglasses. These allergic reactions can cause contact dermatitis, severe irritation and, in extreme cases, infections. Petition 870250011564, dated 12 / 02 / 2025, page 9 / 21 / 12 [5] Traditional methods to minimize these reactions include the use of metallic coatings such as gold or rhodium, which are expensive and do not guarantee long-lasting protection due to wear of the protective layer. Alternatively, processes such as physical vapor deposition (PVD) and plasma electrolytic oxidation (PEO) have been used to create protective layers. However, these solutions involve high costs, require specialized equipment and are not accessible for large-scale applications or the direct consumer market. [6] The specific field of application of the invention encompasses jewelry and costume jewelry making, such as earrings, necklaces and rings, as well as other metal items, such as watches, eyeglasses, clothing buttons and piercings, which frequently cause irritation and allergic reactions due to the presence of metals that can react chemically with the skin. These accessories come into direct and prolonged contact with the skin, often causing allergic reactions and irritation due to the composition of the metals. Humidity, sweat and environmental factors can intensify these problems by facilitating corrosion and wear of the parts. [7] The use of protective coatings for metal parts, especially jewelry and accessories, has been a common practice to prevent allergic reactions and protect against corrosion. However, the methods and materials currently available have limitations in terms of efficiency, cost, accessibility and environmental impact. [8] PVD coatings – Physical Vapor Deposition – are widely used and involve vaporizing a metal and then condensing it onto the surface of the jewelry in a vacuum environment. These coatings are very thin, but extremely durable and resistant. They can be applied to a variety of metals and are known for their resistance to corrosion and wear. [9] Plasma electrolytic oxidation (PEO) is a technique that forms a hard, dense oxide layer on metals such as Petition 870250011564, dated 12 / 02 / 2025, page 10 / 21 / 12 aluminum and titanium, which increases corrosion resistance and biocompatibility. PEO is environmentally friendly and effective for creating coatings on metals that are in prolonged contact with the skin. Electroplating is also a known technique, especially with nickel-free metals, and is used to avoid allergic reactions while providing corrosion protection.

[10] Regarding characteristic coatings for jewelry and costume jewelry, there are variations. Rhodium plating is commonly used to coat white gold and silver jewelry and provides a bright, reflective surface that is highly resistant to tarnishing and corrosion. It also forms a hypoallergenic barrier that can prevent skin irritation caused by nickel and other base metals commonly found in jewelry alloys.

[11] Palladium plating is sometimes used as a hypoallergenic coating for jewelry. It is less likely to cause allergic reactions compared to nickel. It is also durable and tarnish-resistant, making it a good option for avoiding skin irritation. Some platings are specifically designed to be nickel-free in order to avoid allergic reactions. These platings may include alloys made of metals such as titanium or stainless steel.

[12] Ceramic coatings involve applying a thin layer of ceramic material to the surface of the jewelry. Ceramic is hypoallergenic, highly durable, and resistant to scratches and tarnishing. This makes it a good option for coating jewelry to prevent skin irritation.

[13] Gold plating involves applying a thin layer of gold to the surface of the jewelry, usually over a base metal such as silver or copper. Gold is hypoallergenic and does not react with the skin, making it a popular choice for people with sensitive skin. However, it is softer and less durable than other platings, so the thickness of the gold layer is important for longevity.

[14] Lacquer and polymer coatings involve applying a layer of clear varnish or polymer to the surface. They are also relatively Petition 870250011564, dated 12 / 02 / 2025, page 11 / 21 / 12 easy to apply and can be reapplied as needed. Surface coating solutions, such as paints, primers and other polymeric systems, are seemingly limitless.

[15] Paints are a relatively inexpensive method of increasing corrosion resistance. However, the processes involved are highly inefficient; during application, up to 50% of the coating can evaporate and oven curing produces harmful byproducts that are hazardous and expensive to dispose of in large volumes. Although they offer excellent chemical and corrosion resistance, like other polymeric hydrocarbons, paints are soft, meaning they are easily peeled off and abraded.

[16] Powder coatings, like paints, are another relatively inexpensive option. The benefits of powder coatings are practically the same as paints, but thicker protective layers can be applied more efficiently and quickly. The coatings are thick, which adds bulky layers (usually above 80μm) that substantially increase a material's corrosion resistance. The cost of this additional protection is the added thickness, and the aesthetic effects produced are not as attractive and are not consistent throughout the material.

[17] The commercial product Jewelry Shield (UPC 654207168546) is a coating for brush application on jewelry and metal accessories, intended to protect the skin from allergic reactions. It is formulated with three main solvents (methyl ethyl ketone, xylene and ethylbenzene), in addition to a resin that provides a characteristic finish. This product creates an invisible layer that protects sensitive skin and offers durability for up to three months. However, the high concentration of solvents and the absence of natural resins make its composition more aggressive and less sustainable.

[18] The Eternal Jewelry Coating (ASIN B07FYX1J6C) product is a brush-applied coating, but its exact chemical composition is not publicly disclosed. This product uses nanoceramic technology that allows the formation of a durable and resistant coating layer capable of bonding. Petition 870250011564, dated 12 / 02 / 2025, page 12 / 21 / 12 molecularly to the metallic surface. The Eternal Jewelry Coating creates an ultra-thin, wear-resistant protective barrier, as well as repelling water and dust, facilitating the cleaning of the piece and preventing allergies. Although effective for protection, the invention proposed here uses a natural resin base, differing in its simplicity and lower cost.

[19] Patent document US4761971A describes a coating for metallic devices in direct contact with the skin, aimed at preventing allergic reactions and irritations. The composition includes trichloroethane, toluene and methoxyethanol, and is characterized by being biologically inert, adhering permanently to the metal. The coating is composed of transparent plastic, which differentiates it from the use of natural resins, as in the invention proposed here, which seeks temporary and biodegradable protection for parts in direct contact with the skin.

[20] US patent document A-4,861,658 proposes incorporating an allergen into a xylene-based coating on jewelry to make it hypoallergenic.

[21] Patent document JP5832474B2 discloses a coating based on silicone resin or silicone oligomer and alkoxysilane, which forms a protective layer for metallic articles for direct use on the human body. The application covers jewelry, electronics and medical instruments, among others.

[22] Patent document FR2737427B1 describes a method for coating metal objects with cellulose derivatives (cellulose acetate and acetobutyrate) to prevent allergic reactions. The method proposes creating a barrier between the metal and the skin, being a robust and permanent solution with greater technical complexity.

[23] US patent document 20070292468A1 refers to a jewelry coating employing a film former such as a polymer and solvents. The formulation may also include medications to alleviate allergic symptoms, such as antibiotics, an approach that differs from the proposed invention, which is formulated exclusively to provide an anti-allergic barrier. Petition 870250011564, dated 12 / 02 / 2025, page 13 / 21 / 12

[24] Patent document KR100492011B1 describes a coating process for eyeglass frames with layers of high-purity metallic film, which protect against oxidation and increase durability. The formulation includes acrylic polyol resin and cellulose acetate.

[25] Patent document KR20210063945A refers to an antimicrobial and antiallergic polymer coating composition including: a (meth)acrylic polyol resin with a number average molecular weight of 3,000 to 20,000; a (co)polymer including ethylene glycol repeating units; a polyacrylic acid resin; and sodium chlorophyllin salt or a metal complex thereof. Despite its effectiveness, the use of synthetic resins and the lack of focus on biodegradability limit its suitability for modern demands.

[26] Patent document DE-A3,917,376 describes an acrylic resin-based varnish in a solvent mixture, deposited in a state-of-the-art manner on the metal objects to be protected.

[27] Patent document JPH02134314A describes the use of a polyvinyl alcohol-based resin in solution in a ketone-type solvent, applied to the surface of the metal object to be protected. After drying, this resin forms an interposition layer between the metal and the skin. However, studies have shown that polyvinyl alcohol and vinyl derivatives, as well as acrylic resins and acrylates (e.g., methyl methacrylate) are highly allergenic compounds that can cause skin irritation.

[28] Existing solutions predominantly use synthetic resins, aggressive solvents, or approaches with high technical complexity. Various resin film-forming materials, including thermoplastic and thermosetting polymers, can be used, allowing adjustments to the formulation to meet different needs, such as flexibility, durability, and gloss. Solvent selection and the polycondensation reaction are crucial for obtaining a film that is effective in protecting against allergies, as well as providing properties such as hardness and water repellency. In addition, many imported products, such as Jewelry Shield and Eternal Jewelry Coating, face Petition 870250011564, dated 12 / 02 / 2025, page 14 / 21 / 12 logistical difficulties and high costs, which restricts its accessibility in the Brazilian market.

[29] In terms of durability, metallic coatings, such as gold and rhodium, offer aesthetics and protection, but wear out over time and do not prevent all forms of allergies. Alternatives based on synthetic polymers, such as epoxy or acrylic resins, are durable, but can yellow and have a negative environmental impact.

[30] The present invention features a novel formulation with two solvents and a natural resin (not acrylic). The production process is simple without compromising the effectiveness of the coating. The coating is biologically inert, does not react with skin or body fluids and is designed to avoid allergies while maintaining the aesthetic appeal of the piece.

[31] Furthermore, the present invention proposes a practical application, by methods such as brushing or spraying, which allows its adoption by both manufacturers and end consumers. In this sense, the issue of durability will depend on the constant use of the parts, and future maintenance layers can be easily applied by the user.

[32] The main concern is that, being a solvent-based coating, it can emit volatile organic compounds (VOCs), which requires proper ventilation and handling to ensure safety. The coating formula must be applied correctly to ensure a uniform and adherent layer. Any failure in application can result in uncovered areas or inadequate protection, compromising the effectiveness of the coating. Objectives of the Invention

[33] The present invention aims at an innovative approach through an efficient method of manufacturing an anti-allergenic and anti-corrosive protective coating for metal accessories in direct contact with the skin, using a combination of solvents and resins that ensures homogeneity and stability. The coating can be easily applied. Petition 870250011564, dated 12 / 02 / 2025, page 15 / 21 / 12 with brush or spray allowing its use by both manufacturers and end consumers, creating a thin and transparent film after drying. Advantages of the invention

[34] In summary, the present invention has the following main advantages: • The use of natural resin (rosin) gives the formulation an ecological character, reducing dependence on synthetic resins, and it is also composed of resin acids that provide unique properties to the protective film. • The coating extends the lifespan of parts and accessories, increasing customer satisfaction and reducing the need for frequent replacements, resulting in long-term savings. • Accessories coated with this technology can be sold at a premium price due to their anti-allergenic / anti-corrosive properties, which can increase profit margins for manufacturers and sellers. • The coating also allows access to new market segments, reaching consumers who would avoid these accessories due to allergies. • The simplicity of the manufacturing process and the use of readily available materials make the solution economically viable for both consumers and manufacturers. • The method of obtaining the product is efficient, involving moderate heating and controlled agitation, which ensures homogeneity and stability in the formulation. • The formulation allows drying at room temperature in about 30 minutes or, optionally, with hot air, making it quick and convenient to use. Brief description of the invention

[35] The objectives of the present invention are achieved by a process for obtaining an anti-allergenic and anti-corrosive coating, using natural resin (rosin) and specific solvents (xylene and acetone) in controlled proportions. The process involves moderate heating, followed by agitation. Petition 870250011564, dated 12 / 02 / 2025, page 16 / 21 / 12, guaranteeing the formation of a homogeneous and stable solution ready for application. The resulting composition is applied to metal accessories using simple and accessible methods, such as brush and spray. After application, the solution dries and forms a transparent film, which acts as a barrier between the metal and the skin, preventing allergic reactions and protecting against corrosion. Detailed description of the invention

[36] The present invention describes a coating formulated to be applied to metal parts and accessories, with the aim of forming a barrier with anti-allergenic and anti-corrosive protection. This coating forms a transparent and hypoallergenic film on the metal surface and skin, reducing the occurrence of allergies and protecting against corrosion.

[37] The focus of the invention is on the coating composition, which uses a combination of resins and solvents to ensure the formation of a protective film. The coating composition uses natural resin (rosin), known for its adhesive and sustainable properties, combined with solvents (xylene and acetone) that ensure the homogeneity of the solution and facilitate application and drying. The use of rosin resin is a natural and sustainable alternative to commonly used synthetic resins.

[38] The present invention relates that the process begins with the formulation of the composition. Initially, the rosin resin is weighed and added to a container containing the xylene. The system is heated to a controlled temperature under constant stirring. After partial dissolution of the resin, acetone is slowly added to the mixture, ensuring complete solubility of the components. The mixture is stirred until it reaches a uniform and stable consistency, ready for application.

[39] The final composition has a weight ratio of 15-21% (w / v) rosin, 27-34% (v / v) xylene and 55-64% (v / v) acetone and is Petition 870250011564, dated 12 / 02 / 2025, page 17 / 21 / 12 heated to temperatures between 20 and 55°C under constant agitation to ensure complete dissolution of the resin and homogeneity of the composition.

[40] The process for obtaining and applying anti-allergenic and anti-corrosive coating for metal accessories employs only three components, in which xylene acts as the main solvent, providing anti-corrosive properties and facilitating the penetration of the product into metal surfaces; acetone serves as a co-solvent to improve resin dispersion and mixture homogeneity; and rosin resin adds adhesion properties, forming a durable and stable protective film against external agents.

[41] For practical application, it is essential to prepare the surface of the part, which must be clean and dry to ensure that the coating adheres correctly. Residues of dirt, oil or other contaminants may compromise the effectiveness of the protection. To clean the surface, a dry cloth or a cotton swab can be used, depending on the complexity and size of the part.

[42] The coating can be applied using a brush, ideal for precise and controlled applications, especially in detailed areas of the part, or by spray, being effective for covering large areas or multiple parts quickly and evenly. Its ability to adhere to surfaces of different geometries and curvatures makes the coating highly versatile, applicable to various types of parts with complex details, guaranteeing long-lasting and effective protection without compromising the functionality or design of the object.

[43] During application, the coating should be evenly distributed over the surface of the jewelry, ensuring that all areas in contact with the skin are covered. It is important to apply the coating in a thin, even layer to avoid excessive buildup and ensure effective protection.

[44] The degree of thickness may vary depending on the amount of product applied; a more generous layer will result in thicker protection. Petition 870250011564, dated 12 / 02 / 2025, page 18 / 21 / 12 and perceptible to the touch. The layer is designed to fit accessories of varying sizes and shapes, from small pieces such as earrings and rings to larger items such as bracelets and watches, adapting to each surface in a uniform manner.

[45] After application, the solvent evaporates rapidly, forming a transparent plastic layer that isolates the metal. This coating usually dries in 30 minutes, although drying time may vary and, in some cases, it may be more efficient if left on for longer periods.

[46] After drying, the coating gives the piece a soft sheen, does not alter the original surface texture, remaining smooth and without roughness. This characteristic makes the layer ideal for pieces that need comfort in direct contact with the skin, such as necklaces and watches, ensuring that there are no sensory alterations in the use of the pieces.

[47] The lifespan of the coating depends on several factors, such as correct application and the durability of the protective layer. The resin and solvents used in the compound are designed to form a resistant film, but continuous exposure to use and the environment can affect its effectiveness. If the part is removed, reapplication of the product is necessary.

[48] ​​Chemical resistance analysis demonstrated that the coating exhibits stability when exposed to moisture and perspiration, common factors that intensify metallic corrosion and allergic reactions.

[49] For the reasons stated, it is evident that the present invention achieves the objectives it proposes to achieve, offering a practical and accessible approach to solving recurring problems in the metal accessories market, revealing a method capable of producing an anti-allergenic and anti-corrosive coating, creating a protective barrier between the metal and the skin, preventing irritation / allergies, and maintaining the shine and durability of the piece.

[50] Having disclosed some examples of preferred and alternative embodiments of the present invention, it is clear that none of the examples given is limiting to the scope of protection of the present invention, this being Petition 870250011564, dated 12 / 02 / 2025, page 19 / 21 / 12 defined and limited solely by the claim framework and the claims contained therein. Petition 870250011564, dated 12 / 02 / 2025, page 20 / 21

Claims

CLAIMS 1. PROCESS FOR OBTAINING AN ANTI-ALLERGIC AND ANTI-CORROSIVE COATING FOR METAL ACCESSORIES characterized by comprising the following steps: heating the natural resin rosin rosin at a temperature between 20°C and 55°C in a proportion of 15% to 21% w / v, followed by the addition, under constant stirring, of 55% to 64% v / v of the solvent xylene and acetone in a proportion of 27% to 34% v / v, ensuring complete dissolution of the resin and homogeneity of the formulation for application.

2. APPLICATION OF ANTI-ALLERGIC AND ANTI-CORROSIVE COATING FOR METAL ACCESSORIES, characterized by forming a continuous and transparent protective layer film after drying on metal surfaces, with adhesive and protective properties, which prevents allergic reactions caused by direct contact between the skin and these metals, and prevents corrosion, increasing the durability of the parts.

3. APPLICATION OF ANTI-ALLERGIC AND ANTI-CORROSIVE COATING FOR METAL ACCESSORIES, according to claim 2, characterized by being carried out with a brush or by spray on clean metal accessories; after application, it is necessary to allow the piece to dry, with a drying time of at least 30 minutes, which may occur at room temperature or with the aid of hot air. Petition 870250011564, dated 12 / 02 / 2025, page 21 / 21