1. Understand Acrylic Material
Acrylic, also known as PMMA or acrylic, comes from English acrylic (acrylic plastic). The chemical name is polymethyl methacrylate, which is an important plastic polymer material developed earlier. It has good transparency, chemical stability and weather resistance, easy to dye, easy to process, and beautiful appearance. It is widely used in the construction industry. Has a wide range of applications. Plexiglass products can generally be divided into cast sheets, extruded sheets and molding compounds.
2. Application Of Acrylic Bottles In The Cosmetics Industry
In the field of Cosmetic Bottle Packaging, Acrylic Bottles are widely used in cosmetic packaging such as high-end creams and lotions, and are very popular in the market. Acrylic bottles not only have the characteristics of plastic: drop resistance, light weight, easy coloring, easy processing, and low cost, but also have the characteristics of glass bottles with beautiful appearance and high-grade texture. It allows cosmetics manufacturers to use the cost of plastic bottles to obtain the appearance of glass bottles, and it also has the advantages of resistance to falling and transportation. Acrylic packaging bottles have a wide variety, rich colors, and have excellent comprehensive performance, providing designers with a variety of choices. They can be dyed, and the surface can be painted, silk-screened or vacuum-coated. At present, the domestic acrylic cosmetic bottle manufacturers are relatively concentrated in Shangyu, Zhejiang. The manufacturers here are also the first batch of manufacturers to start acrylic packaging production in China, and their products are exported to the European and American cosmetic bottle packaging markets.
Acrylic packaging bottles have excellent transparency, with a light transmittance of over 92%, good anti-aging performance, and can be used outdoors with peace of mind. Although acrylic bottles have achieved great success in the cosmetics market, they have not been widely used in other packaging fields such as food and medicine. This is also a field worth exploring and exploring for acrylic bottle manufacturers.
3. Acrylic Processing Technology
Casting molding is used to form plexiglass sheets, rods and other profiles, that is, the profiles are formed by bulk polymerization. The molded products need to be post-treated, and the post-treatment conditions are 2 hours at 60°C and 2 hours at 120°C.
(2). Injection Molding
Injection molding adopts the pellets prepared by suspension polymerization, and the molding is carried out on ordinary plunger or screw injection molding machines. Injection molded products also need post-processing to eliminate internal stress. The processing is carried out in a hot air circulation drying oven at 70-80 ° C. The processing time depends on the thickness of the product, and generally takes about 4 hours.
(3). Extrusion Molding
Polymethyl methacrylate can also be formed by extrusion, and plexiglass plates, rods, pipes, sheets, etc. are prepared from the particles produced by suspension polymerization, but the profiles prepared in this way, especially the plates, have a small molecular weight. The mechanical properties, heat resistance, and solvent resistance are not as good as those of casting profiles, and its advantage is high production efficiency, especially for pipes and other casting molds. Difficult-to-manufacture profiles. Extrusion molding can use single-stage or double-stage exhaust extruder, and the screw length-to-diameter ratio is generally 20-25. Table 2 is the typical process conditions of extrusion molding
Thermoforming is the process of making plexiglass sheets or sheets into products of various sizes and shapes. The blanks cut to the required size are clamped on the mold frame, heated to soften them, and then pressed to make them adhere to the mold surface. , to obtain the same shape as the profile, and trim the edges after cooling and shaping to obtain the product. Pressurization can be done by vacuum drawing or by directly pressurizing the punch with the profile. The thermoforming temperature can refer to the recommended temperature range in Table 3. When using rapid vacuum low-draw molding products, it is advisable to use a temperature close to the lower limit. When forming a deep-drawn product with complex shapes, it is advisable to use a temperature close to the upper limit. Generally, the normal temperature is used.
(5). Engraving And Cutting
It is mainly for hollowing out and engraving of formed acrylic or colored acrylic materials. Ordinary laser engraving and cutting machines can meet the engraving and hollowing needs of most acrylic products.
4. Process Characteristics
(1). Polymethyl methacrylate contains polar side methyl groups and has obvious hygroscopicity. The water absorption rate is generally 0.3%-0.4%. It must be dried before molding. The drying condition is to dry at 80°C-85°C for 4-5h .
(2). Polymethyl methacrylate has effective and obvious non-Newtonian fluid characteristics in the temperature range of molding processing. The melt viscosity will decrease significantly with the increase of shear rate, and the melt viscosity is also very sensitive to temperature changes. Therefore, for the molding process of polymethyl methacrylate, increasing the molding pressure and temperature can significantly reduce the melt viscosity and achieve better fluidity.
(3). The temperature at which polymethyl methacrylate begins to flow is about 160°C, and the temperature at which it begins to decompose is higher than 270°C, which has a wide processing temperature range.
(4). Polymethyl methacrylate has high melt viscosity and fast cooling rate, and the product is prone to internal stress. Therefore, strict control of process conditions is required during molding, and post-processing is also required after molding.
(5). Polymethyl methacrylate is an amorphous polymer, and its shrinkage rate and its variation range are small, generally about 0.5%-0.8%, which is conducive to forming plastic parts with high dimensional accuracy.
(6). Polymethyl methacrylate has very good cutting performance, and its profiles can be easily machined into various required sizes.
*Maypak packaging is Acrylic Bottle Manufacturer and has been focusing on acrylic bottles for more than 17 years and was established in 2006,the company enjoys a good reputation at home and abroad. If you have any questions about lipstick tubes, please contact us.
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