Is the resin of the 3D printer toxic?

This article explores the toxicity of 3D printer resin, analyzing its composition, short and long-term exposure effects, and providing safety precautions. It also offers ways to reduce toxicity risks, including optimizing operations, strengthening protection, improving the environment, and choosing low-toxicity resins.

Composition of 3D printer resin

• Oligomer (Oligomer) : Refers to low molecular weight polymers with unsaturated functional groups in the photosensitive resin component, and active groups at the molecular end of the light-curing reaction, such as unsaturated double bonds and epoxy groups. After initiating polymerization, the molecular weight solidifies and rises to a solid, which is the largest component and the key to determining the quality. Common oligomers include polyacrylic resin, epoxy acrylic resin, and polyurethane acrylic resin.
• Active monomer (active diluent) : As a defensible functional group in photosensitive resin, it is responsible for reducing the viscosity of the entire resin system and preventing the print head from clogging. Its main components include acrylic esters, vinyl ethers, etc.
• Photoinitiator : It is a compound that can cause polymerization. Its principle is that the photoinitiator or photosensitizer absorbs energy, and then is excited from the ground state to the excited state. When the excited state energy is large, weak bonds break to form primary active species. According to the different absorption energy, it can be divided into ultraviolet light initiators and visible light initiators. According to the different formation activity, it can be divided into free radicals and cations. Free radical photoinitiators mainly include benzoin and ether derivatives, benzophenone, etc. In addition, there are additives, which are auxiliary materials in 3D printing resins and can improve the rheology, viscosity, mechanical properties and other characteristics of resins.

Toxicity analysis of 3D printer resin

• Short-term exposure effects : If it is only a short-term exposure, it usually does not cause harm to health. Because these toxic ingredients are released in small amounts under normal working conditions, there is no need to worry too much.
• Long-term exposure effects : Long-term exposure or accidental ingestion may have an impact on the nervous system, leading to discomfort symptoms such as dizziness, headache, decreased sleep quality, and decreased memory. There may also be symptoms such as itchy skin, tearing eyes, and rashes, blisters, coughs, and other symptoms, which can sometimes be very serious. As this is a cumulative process, there may be no feeling at first until the body reacts, which may be too late.

Safety precautions for using 3D printer resin

Personal protective equipment

• Gloves : Nitrile gloves must be worn when handling resins or prints (do not use latex gloves), and if possible, gloves should have extended cuffs to prevent the resin from contacting the skin. Because toxic components in the resin may enter the human body through skin contact, long-term accumulation can cause harm to health.
• Masks or gas masks : Wear masks such as N99, or even gas masks, to prevent inhalation of toxic gases emitted by the resin. Because the resin may release gases containing toxic components such as benzophenone and mithrone during the printing process, inhalation may cause damage to the respiratory and nervous systems.
• Goggles or safety glasses : prevent resin from dripping into the eyes and protect the eyes from injury. Because if the resin accidentally enters the eyes, it may cause discomfort symptoms such as eye pain, tearing, and swelling, and in severe cases, it may affect vision.
• Protective clothing : Wear a lab coat or suitable covering over personal clothing to avoid resin contact with clothing, prevent resin from splashing on the body during operation, and reduce the risk of skin exposure.

Work environment requirements

• Ventilation :
  • 3D printers and uncured open resin should be stored and operated in a well-ventilated or locally ventilated area. Ventilation is a very important measure to discharge toxic fumes emitted by the resin from the work area. Simply opening doors and windows for ventilation may not be effective. It is best to use external vents and electric fans. If conditions permit, smoke exhaust devices can be installed, especially when effective natural ventilation is not possible. Professional or industrial 3D printers generally come with such devices, while desktop 3D printers often need to be purchased and installed by themselves.
  • Avoid placing 3D printers on carpeted areas or using barriers to avoid damaging the carpet. If there is an odor problem, do not set up a dedicated work/personal space near the printer.
• Avoid heat and ignition sources : Do not expose UV curable resins to heat (110 ° C/230 ° F or above), flames, sparks, or any ignition source to prevent dangerous situations such as resin combustion or explosion, because resins may be flammable substances. Contact with heat or ignition sources may cause fires or release more toxic gases.

Operating standards

• According to the operation manual : The operator must operate the machine safely according to the manufacturer’s manual, which is the premise of ensuring safety. Different 3D printers may have different operation requirements and safety precautions. Strictly following the manual operation can avoid safety issues caused by misoperation.
• Handling Ink Cartridges and Resin Bottles : If the UV-curable resin is in a sealed cartridge, check the cartridge before loading it into the printer. Do not use leaking or damaged cartridges. If the UV-curable resin is in a dumping bottle, carefully pour the liquid from the storage bottle into the printer tray to avoid overflow and dripping. If there is a leak or damage to the ink cartridge, handle it according to local regulations and contact the supplier.
• Cleaning and post-treatment :
  • Before reusing tools that may be contaminated with materials, clean them with a large amount of ethanol or isopropanol, or follow the instructions of the resin SDS, and then wash them thoroughly with soap and water.
  • Please wear gloves to remove the parts from the printer and clean them with the manufacturer’s recommended solvent (such as isopropyl alcohol or topical alcohol) before post-curing. According to the printer manufacturer’s recommendations, ensure that all 3D printed parts are irradiated with ultraviolet light and thoroughly cured after molding.
  • After the operation, please wash your hands, face, or any body parts that may come into contact with UV-curing resin with a mild skin cleanser and soap – do not use solvents. Clean any contact or exposed surfaces to prevent contamination, clean with ethanol or isopropanol, or follow the instructions of the resin SDS, and then thoroughly wash with soap and water. If the resin is accidentally touched, immediately rinse the contaminated eyes or skin with plenty of water for 15 minutes, and if necessary, wash the skin with soap and plenty of water or anhydrous cleanser. If skin irritation or rash occurs, seek qualified medical attention. If accidentally ingested, do not induce vomiting and seek medical attention immediately.

How to reduce the toxicity risk of 3D printer resin

Optimize the operation process

• Reduce contact time and frequency : Minimize contact time and frequency with resin while meeting printing needs. For example, arrange printing tasks reasonably to avoid unnecessary frequent operation of the printer and resin processing.
• Standardized operation actions : Adding resin, removing printed parts, and post-processing according to the correct operation method. During the operation, the action should be gentle to avoid resin splashing or overflow and reduce unnecessary exposure risks.
• Keep the work area clean : Clean up the resin drips, residues, etc. in the work area in time to prevent the resin from remaining in the work area for a long time and continuously releasing toxic substances. Regularly deep clean the work area, including the surface of the printer, tools, desktop, etc.

Strengthen protective measures

• Choose the right protective equipment : In addition to the basic protective equipment such as gloves, masks, goggles, and protective clothing mentioned earlier, you can also choose higher-level protective equipment according to the actual situation. For example, if the odor emitted by the resin is very strong or the concentration of toxic gases is high, you can choose a gas mask with an activated carbon filter layer to improve protection against toxic gases.
• Ensure the correct use and maintenance of protective equipment : Wear protective equipment correctly to ensure that it can effectively play a protective role. For example, gloves should fit the hands, masks should fit tightly to the face, and goggles should be adjusted to the appropriate position. At the same time, regularly inspect and replace protective equipment, such as replacing gloves in a timely manner when they are damaged or the filtering effect of masks decreases.

Improving the working environment

• Enhance ventilation effect : If the natural ventilation effect is not good, you can consider installing more powerful ventilation equipment, such as industrial exhaust fans, ventilation ducts, etc., to improve ventilation efficiency and ensure that the toxic gases emitted by the resin can be discharged from the work area in time. You can also use an air purifier to filter and purify the air in the work area, reducing the content of toxic substances.
• Set up a separate workspace : If conditions permit, set up a separate workspace for the 3D printer, isolating it from the personnel activity area. This can reduce the impact of toxic gases emitted by the resin on the surrounding environment, and also facilitate centralized ventilation and management of the work area.

Choose low-toxicity resins

• Pay attention to the composition and characteristics of the resin : When choosing 3D printing resin, carefully read the product manual and related information to understand the composition of the resin, and try to choose resin products that are marked with low volatility and low toxicity. For example, some new environmentally friendly resins may use special formulas to reduce the use of toxic ingredients.
• Refer to the evaluation and experience of other users : You can understand the feedback and evaluation of other users on the toxicity of different resin products through online forums, communities, product evaluation websites and other channels. This can help us screen out relatively low toxicity products among many resin products.