Which opening agent is better for polyethylene rubber isolation film?
Through femtosecond detection, it is found that the polyethylene rubber anti-blocking agent is a functional substance between the mold and the product. In the rubber and plastic manufacturing industry, when manufacturing model products, in order to release the mold, improve production efficiency, and prolong the service life of the mold,
At the same time, make the product smooth and clean, the size is qualified, and reduce waste,
It is an indispensable auxiliary that needs to be used. Its main function is to make the demoulding operation easy and prevent damage to the product caused by forced removal. The isolation of the anti-blocking agent depends on its surface properties. Its notable feature is that the critical surface tension is small and it is difficult to be wetted by liquid. Because of this, the release effect can be achieved. Rubber opening agent refers to a type of substance used to prevent the rubber product from sticking to the surface of the mold, and to enable it to be released from the mold without tearing. Fluorine anti-blocking agent inherits the characteristics of fluorine-containing materials, which can significantly reduce the surface energy of solids, making it hard to wet and non-adhesive, and not easy to dissolve with other substances, which solves the problem of bonding between the finished product and the mold. , When formulated as an opening agent, the amount of fluorine-containing compounds is extremely small. It is suitable for thermosetting resin, thermoplastic resin and various rubber parts. The surface of the molded product is smooth and clean, and the secondary processing performance is excellent. It is especially suitable for the demoulding of fine electronic parts.
1) Polytetrafluoroethylene (relative molecular mass 1800);
2) Fluorine resin powder (low molecular weight PTFE);
3) Fluorine resin coating (PTFE, FEP, PFA).
Silicone anti-blocking agent
Silicone anti-blocking agent is prepared from organosiloxane, which has the advantages of good heat resistance, moderate surface tension, easy to form a uniform isolation film, and long mold release life. The disadvantage is that there is a layer of oily surface on the surface of the product after demoulding, and the surface must be cleaned for secondary processing. Commonly used are silicone oil, silicone rubber, emulsified silicone oil and silicone grease. Silicone anti-blocking agents are the mainstream products in the mid-range market of rubber and plastic anti-blocking agents, and are widely used in the processing of resins such as polyurethane, rubber, polyethylene, and polyvinyl chloride.
1) Methyl branched silicone oil (No. 128 silicone oil), directly used for demoulding.
2) Methyl silicone oil: Dissolve methyl silicone oil with a viscosity of 300~1000cp in gasoline (or toluene, xylene, dichloroethane) to make a 0.15%~2% silicone oil solution. It is suitable for demoulding of rubber and plastic model products.
3) Emulsified methyl silicone oil. Formulated into water emulsion containing 35% ~ 40% silicone oil (need to add emulsifier such as Tween 20, Pingpingjia or polyethylene
enol, the dosage is about 2% of the silicone oil content). Then add water to dilute to 0.1% ~ 5% of silicone oil, spray it on the mold, remove water by heating, and make the silicone oil settle on the surface of the mold cavity. Suitable for all kinds of rubber and plastic products.
4) Hydrogen-containing methyl silicone oil. Use 30 parts of 202# and 821# silicone oil, 4 parts of n-butyl phthalate, and 300 parts of solvent gasoline with a viscosity of 5 to 50cp to make a solution, and spray it into the cavity of a 150 e hot mold. Suitable for inner tube opening agent.
5) 295# silicone grease, diluted with solvents such as toluene or rosin water, mixed thoroughly, and then sprayed in the mold cavity. Suitable for rubber, plastic laminates and other products.
6) Silicone resin: Dissolve 1# or 2# silicone resin in toluene to make a 3%~9% solution, suitable for rubber products.
7) Silicone rubber: Prepare methyl (or methyl vinyl) silicone rubber as a 10% gasoline solution for storage, and then dilute it with gasoline at a ratio of 1:28 and mix well. It is suitable for demoulding of conveyor belt products.
8) Toluene solution of silicone rubber. Dissolve silicone rubber in toluene to make a 1%-2% solution. Suitable for mold release of rubber, polyethylene, polystyrene products
Wax (oil) based anti-blocking agent
Wax oil series anti-blocking agent is characterized by low price and good adhesion performance, but the disadvantage is that it pollutes the mold. Its main varieties are:
1) Vaseline for industrial use, directly used as an anti-opening agent.
2) Paraffin, used directly as an anti-opening agent.
3) Sulfonated vegetable oil, directly used as anti-blocking agent.
4) Printing and dyeing oil (Turkish red oil, Swire oil), the emulsion made by adding 0.9~2 parts of printing and dyeing oil to 100 parts of boiling water has a better demoulding effect than soapy water.
5) Polyethylene wax (relative molecular mass 1500~2500). Mixing polyethylene with a certain proportion of emulsifier is suitable for opening agent of rubber products.
6) Polyethylene glycol (relative molecular weight 200~1500), directly used for demoulding of rubber products.
Surfactant-based anti-blocking agent
The surfactant anti-blocking agent is characterized by good isolation performance, but pollutes the mold. There are mainly the following categories:
1) Soapy water. Use soap to make a certain concentration of aqueous solution, which can be used as a lubricant for molds and as a core remover for rubber hoses.
2) Sodium oleate. Mix 22 parts of oleic acid with 100 parts of water, heat to near boiling, then slowly add 3 parts of caustic soda, and stir until
Saponification, control the pH value to 7~9. Dilute 1:1 with water when used. When it is used for tire vulcanization and demoulding, 2 parts of glycerin should be added to 200 parts of the above solution.
3) Glycerin. It can be directly used as anti-blocking compound or water tire lubricant.
4) Aluminum fatty acid solution. Dissolve fatty aluminum in dichloroethane to make a 1% solution. Suitable for polyurethane products, one coat, can be
Repeated use many times, the demoulding effect is good.
5) Zinc stearate is an anti-blocking agent for transparent plastic products.
Other types of mouthpieces
1) Polyvinyl alcohol. The formula is 5 parts of polyvinyl alcohol, 35 parts of alcohol, and 1 part of washing powder; the preparation process is to dissolve polyvinyl alcohol with part of the water (heat 60-70 degrees), then add enough water, stir well, then add alcohol and dissolve For good detergent, mix until the white precipitate is dissolved. Suitable for mold release of unsaturated polyester and epoxy resin moldings.
2) Polyacrylamide: the formulation, preparation process and application are the same as (1).
3) The organic solvent solution of cellulose acetate and polystyrene can also be used as an anti-blocking agent.
4) The organic solvent solution of cellulose acetate and polystyrene can also be used as an anti-blocking agent.
5) Water-based opening agents containing masking agents. Formula: 2.7 parts of microcrystalline wax, 2.0 parts of polysiloxane, 7.88 parts of thick petrolatum, fungicide
0.1 parts, fatty alcohol adduct 1.5 parts, nonylphenol EO adduct 0.4 parts, fatty alcohol and polyethylene glycol ether mixture 0.32 parts, water 84.73 parts. First heat one-half of the water to 95 degrees, then add the above-mentioned components one after another under stirring, and add the corresponding emulsifier. It is suitable as an anti-blocking agent for polyurethane products.
6) Durable opening agent. In 200ml mixed solvent (
Xylene: ethylbenzene: ethane: toluene = 82:16:5:1), add Me3SiCl 1.6, Si (OEt) 4 1.0, water 19.2mol,
Stir at 25°C to 40°C for 1h to obtain a silicone resin solution. Then this solution 15, dimethyl siloxane (viscosity 200Pa.s) 66, mixed solvent 19
mix. Make a 4%~10% solution with dichloromethane. It is suitable for demoulding of polyurethane foam products, and one coating film can be reused hundreds of times.
7) Multi-layer compound anti-blocking agent. The bottom layer is short-chain tetrafluoroethylene telomer; the second layer is polyethylene; the third layer is polyvinyl alcohol.
If the bottom layer is damaged after long-term use, it should be updated in time; the second and third layers need to be updated frequently. It is suitable for demoulding of polyurethane ultra-microporous products.
Internal opening agent
1) Zinc stearate, ammonium stearate, paraffin, etc. should be used as internal anti-blocking agents.
Anti-blocking agent, also known as slip agent, anti-blocking agent, anti-caking agent, etc., is often used in the production and preparation of plastic film materials, which can effectively improve the opening performance of the film. The earliest anti-blocking agents are inorganic talcum powder, diatomaceous earth, etc.; the mid-term development is organic oleic acid amide, erucamide and EBS derivatives, etc.; chemical additives that must be added to low-density polyethylene (LDPE) film materials. Adding 0.1-0.5 oleic acid amide to the low-density polyethylene film material can not only improve the antistatic and lubricating properties, but also improve the moisture-proof performance, can significantly reduce the friction coefficient and adhesion resistance, and significantly improve the blown film (extrusion) It can effectively prevent the bonding between the films and the agglomeration between the pellets, increase the smoothness of the film surface, prevent the accumulation of dust on the surface of the product, and produce a very smooth plastic product.
