[patent abstract] the invention relates to A production method of polyurethane latex condom. A) prepare polyurethane latex, mix water-based polyurethane with an auxiliary agent with solid content of 35%~55% and stir it evenly to obtain polyurethane latex.B) polyurethane latex obtained in step A above is used for molding with A condom mold to obtain polyurethane latex condom;The mould is prepared from polyolefin materials, and the polyolefin materials are polyethylene and/or polypropylene.The invention also provides a special mould for producing polyurethane latex condoms.
The invention discloses a production method of polyurethane latex condom and a special mould thereof
The invention relates to a condom, in particular to a production method of polyurethane latex condom and a special mould thereof.
Condoms are one of the most widely used contraceptives in the world.In the existing technology, the main raw material for making condoms is natural latex, but natural latex condoms have the risk of sensitization and nitrosamines causing cancer.Therefore, looking for a more suitable raw material to produce condoms is the inevitable trend of condom production development.
Compared with natural latex condoms, polyurethane condoms with non-toxic, high strength, good thermal conductivity, no allergic reactions and other characteristics, heat, humidity and uv light is not sensitive, good aging resistance, in the storage process is not affected by a variety of oil-based lubricants.Polyurethane condom barrier effect is very high, can effectively contraception and filter HIV, is a safe and comfortable use of condoms.
Condoms generally adopts direct immersion method of assembly line production plant, with the number of mold in the assembly line, each clamping mould respectively by special mould clamping equipment, in terms of a single condom production, its in the transmission device, in turn, complete immersion latex a dry cooling a second dip latex, dry cooling terminating time dipped latex a dry a curling a dry - water stripping a centrifugal dehydration is a finishing a finished product drying steps.In industrial production, because the condom production line needs to transfer thousands of molds at the same time, the transmission capacity of conveyor belt mainly determines the weight of each mold, and thus determines the energy consumption of production, mold weight will increase the burden of transmission equipment and increase the energy consumption of production.The mould material, therefore, in addition to conform to the requirements of the work, also need to have the right price, weight, can realize the industrialization of the condom, in addition, the mold also processed into the shape of a right, because the mould based on the slender rod, also has the end, thread, such as structure, or according to need to be processed into the hollow structure, so it can processing performance are also should consider the factors in the industrial production.
In addition, condom film should be able to adhere to the mold and to meet the requirements of easy edge, demoulding process, so that the mold material must have appropriate surface energy.In the existing technology, the mold material of natural latex contraceptive set is glass, ceramic, stainless steel, etc., and the surface energy of polyurethane is about 43mN/m, while the surface energy of glass (70mN/m) and stainless steel (75mN/m) is too high. The polyurethane condom will firmly attach to its surface and bond with the mold, resulting in the problems of difficult edge curling and film dropping.PTFE is used to solve the problem of mold release. It is proved by experiments that the surface energy of PTFE (18.5mn /m) is too low. When impregnated, polyurethane latex is prone to "slip glue phenomenon", resulting in incomplete attachment of condom film, which cannot meet the requirements of qualified rate of industrial production.In addition, PTFE is expensive and has high density (2.14 ~2.2g/ cm3), which makes it extremely difficult to process, because PTFE melting temperature is as high as 327?342°C, and the melt viscosity is very high (103Pa*s), which is difficult to flow, and can not be processed by the common thermoplastic resin method.Therefore, the molding process of PTFE condoms is very complicated. PTFE rods with appropriate diameter need to be produced by molding and pressing first, and the required shape needs to be turned by the recar bed.Obviously, turning and processing costs are high for the mould with complex structure, which is time consuming and material consuming. Besides, due to its high density, the weight of the mould is large. The solid mould also needs to be drilled to reduce the weight of a single mould.For this reason, PTFE mold is difficult to adapt to the industrial production of polyurethane condoms due to its "slippery rubber phenomenon", extremely difficult processing, high cost and large weight.
The invention provides a polyurethane latex condom production method to solve the technical problems existing in the process of industrial production of polyurethane condoms with existing technologies, which greatly reduces the adhesion force of polyurethane rubber film on the surface of mold, has the characteristics of easy edge rolling and film dropping, and can reduce the production cost.
The invention also aims to provide a special mould for the production method mentioned above, which has the advantages of low cost and good machinability.
The invention relates to A method of polyurethane latex condom production includes the following steps: A) preparation of polyurethane latex, the solid content is 359 Γ 55% of waterborne polyurethane emulsion mixed with additives and stir well, for A quick polyurethane latex;B) polyurethane latex obtained in step A above is used for molding with A condom mold to obtain polyurethane latex condom;Wherein, the mould is prepared from polyolefin materials, and the polyolefin materials are polyethylene (PE) and/or polypropylene (PP).A polyurethane latex condom production special die, for the application of it in the production of ammonia ester latex condoms, it consists of a convex head, cylinder and ring card pad, described convex one form is above the front end of the cylinder head, cylinder including ontology and connecting column, ring card pad set described in ontology and the connection between column, the connection with external thread is formed on the column.
Beneficial effects of the present invention is that: the invention of waterborne polyurethane emulsion could be limited to 359 Γ solid content 55%, can guarantee of polyurethane latex has good film-forming performance, get the polyurethane film thickness suitable when impregnated, and film uniformity good flowing property;The invention adopts polyethylene (PP) and polypropylene (PE) as mold materials to solve the following problems: 1. The surface energy of PP and PE materials "PE (33mN/m) and PP (29mN/m)" is suitable, and the dip will not occur the phenomenon of slip glue, and can meet the requirements of edge curling and mold stripping, solving the difficult problem of edge curling and mold stripping in the production of polyurethane condoms.
2. Cheap mold price, diverse molding methods, easy mass production, and convenient secondary processing;PP, PE processing performance is good, can use injection molding, blow molding, extrusion and other methods to process PP, PE condom mold, production process is simple, and injection molding workers can efficiently mass production of a large number of molds, production and processing costs are low.
3. Low density of PP and PE, light mold weight, can effectively reduce the burden of production line and reduce energy consumption.PP, PE is the most productive varieties of common plastics, has a low price, small density (PP for 0. 9 (Γ, 91 g/cm3, I3E as 0. 92?As the density of PP and PE is less than that of glass, PTFE and stainless steel, the mould weight is greatly reduced, which can effectively reduce the burden of the production line and reduce energy consumption.
Therefore, PP, PE material chosen for the condom mold material effectively solve the edge, demoulding difficult technical problems at the same time, with low price, qualitative light, and the advantage of convenient processing, in the realization of the mould optimization, production line optimization at the same time, get together ammoniac ester latex and optimization of formula, to solve the technical problems in the industrialization of polyurethane condoms.
The mould for the production of polyurethane latex condoms is provided with outer spiral lines formed on the connecting column on the side of the ring card pad, which can be directly connected to the threaded hole in the mould base of the impregnating machine. Without additional mould clamping equipment, it is very convenient to disassemble and install, and the production line is further optimized, which is suitable for mass production.