Performance and application of VAE emulsion
Anruijie
Beijing Organic Chemical Factory
VAE emulsion is vinyl acetate - ethylene* **Polymer emulsion is an adhesive with excellent performance. VAE emulsion is non-toxic, odorless, affordable and has excellent bonding effects on surfaces of many different materials. Therefore, this adhesive has a wide range of applications in many fields.
VAE emulsion is a water dispersion system, thus avoiding the impact of solvents on the environment and potential safety hazards. Ethylene gives the polymer soft properties that are permanent and unaffected by the environment and climate. VAE emulsion can not only be used as an excellent adhesive alone for bonding paper, wood, plastic, synthetic cloth, etc., but can also be easily combined with thickeners, surfactants, PH regulators, plasticizers, Solvents, preservatives, fillers and other ingredients are mixed to make various special-purpose adhesives.
1. Add thickener
Water-soluble polymer thickener can increase the viscosity of the continuous phase between dispersed polymer particles, thereby increasing the viscosity of VAE emulsion. Sodium polyacrylate is a very effective thickener for VAE emulsions. When the added amount of thickener is less than 1%, it has little effect on the peel strength. When 7% is added, the bonding strength is significantly reduced.
Carboxyl styrene-butadiene emulsion can significantly increase the viscosity of VAE emulsion and improve the bonding strength to PVC, PP and other base materials. However, attention should be paid to controlling the amount added to prevent the viscosity from being too high.
2. Add surfactants
Adding surfactants such as alkyl polyoxyethylene ether and MS-1 to VAE emulsion can make difficult-to-wet surfaces (such as PVC film, etc.) to improve wettability. The effective concentration is 0.1 to 1.0% surfactant per 100 parts of emulsion.
Adhesives made with VAE emulsion generally do not require the addition of defoaming agents. If there is foam, add 0.1 to 0.2% defoaming agent 7010 or F691.
3. Add pH regulator
VAE emulsion is generally stable in the pH range of 3.0 to 8.5. If the pH of a mixture containing VAE emulsion is adjusted below 3.0, it will result in excessively high synergistic viscosity and more rapid hydrolysis in the wet state, resulting in a lower and lower pH value. When the VAE emulsion is mixed with a dispersion with a completely different pH (for example, a pH of 9.0), the pH of the VAE emulsion should first be adjusted to above 7 with an alkaline substance. Minimize the effects caused by pH differences. Ammonia and sodium hydroxide are commonly used pH adjusters for VAE emulsions.
4. Add plasticizers and solvents
Adding plasticizers can reduce the cost of the formulation because a higher synergistic viscosity can be obtained. This viscosity-increasing effect allows the viscosity to be formulated with water to the desired viscosity, thus reducing the viscosity. The addition of plasticizers and solvents can also improve the properties of substrates that are difficult to bond during construction. Figure 1 shows several plasticizers: dibutyl phthalate, butyl phenyl phthalate, dipropylene glycol phthalate, and dioctyl phthalate. The case where BJ-705 is thickened by adding concentration.
Solvents compatible with VAE emulsion include 3-methoxybutyl acetate, butyl acetate, isobutyl acetate, isophorone, toluene, xylene, methyl isobutyl (methyl isobutyl) ) ketone, methanol, "Texanol" alcohol ester, etc. In addition to affecting the viscosity of the emulsion, adding solvent can also moisten the surface of the adherend and improve the adhesion to the bonding surface. For example: adding 1 to 10 parts of toluene per 100 parts of emulsion can help wet an oily surface such as a plasticized PVC film. Even trace amounts of plasticizer seeping out on the surface of such a PVC film will cause the adhesion to deteriorate. It's very difficult. The addition of solvent can therefore promote adhesion to this surface.
Table 1 lists representative bond strength values ??for VAE emulsions modified by adding 10% dibutyl phthalate.
Table 1 Peel strength of plasticized VAE emulsion lamination and bonding in air drying
Adding plasticizer can improve the bonding strength and adhesion of VAE emulsion to Mylar polyester. Bonding strength to K-type cellophane. In this case, dibutyl phthalate increased the bond strength more than it decreased it.
Adding 15% to 25% isocyanate adhesion promoter to BJ-705 can usually improve the adhesion to "Mylar" polyester.
Because this adhesive is cross-linked on the surface of "Mylar". This mechanism is the same as that of adding plasticizers. Both the addition of plasticizer and the addition of isocyanate add polar materials to the VAE emulsion to improve adhesion to the polar matrix. Adding plasticizers to non-polar matrices will not only fail to improve the bonding strength, but will instead reduce it.
5. Add fillers
In adhesives based on VAE emulsion, low-cost fillers such as clay and calcium carbonate can be added as fillers or fillers. Adding dry fillers can significantly increase the viscosity of the emulsion. If the filler is first dispersed with water, then large amounts of filler can be added without making the workable viscosity unduly high. BJ-707 can accept more fillers than other varieties.
6. Wet strength additives
The water resistance of VAE emulsion generally meets the requirements. Where improvements are needed, dialdehyde, water-soluble urea-formaldehyde resin (UF), melamine resin (MF) or phenolic resin can be added. Excellent water resistance can be achieved by heat curing.
The application of VAE emulsion is mainly reflected in the following aspects:
1. Adhesives for surface bonding
VAE emulsion and VAE emulsion-based 's adhesive provides better bonding to difficult-to-bond compositions than vinyl acetate homopolymer emulsion. In the furniture industry, VAE emulsion can be used to bond polyvinyl chloride decorative films to laminates, particleboards, hardboards or fiberboards; to bond fireproof veneers to laminates, particleboards, hardboards or fiberboards; to bond wood-like ( Such as beech, ash, etc.) veneer and particleboard, hardboard or fiberboard bonding. In recent years, with the rapid development of my country's packaging industry, paper-plastic composite products have been widely used in commodity packaging. VAE emulsion can be made into a laminating adhesive with excellent performance by adding a small amount of additives, which can be used for laminating polyvinyl chloride film, oriented polypropylene film, polyolefin film with color printing paper, kraft paper, etc. In wall insulation in the construction industry, VAE emulsions are used as adhesives for polystyrene foam boards and concrete walls. Since VAE emulsion has excellent bonding properties to fibers, VAE emulsion is also widely used in the production of non-woven fabrics and the bonding of non-woven fabrics. VAE emulsion can be used as an adhesive for rigid non-woven fabrics, carpet backing adhesive, etc.
2. Adhesive for particle bonding
VAE emulsion can bind cheap fillers at a very high ratio and maintain sufficient bonding force, thus achieving good Balanced costs. VAE emulsion can be used as a caulking adhesive between drywall boards. VAE emulsions also have extraordinary performance in some special fields: for example, the flame retardant antimony oxide, halide or phosphide is bonded to the matrix to increase flame retardancy; the barite (barium sulfate) is bonded to the matrix to increase the flame retardancy. To achieve the purpose of noise reduction. Using VAE emulsion as the base material, mid-to-high-end interior and exterior wall coatings can be produced. The waterproof coating based on VAE emulsion has excellent weather resistance, acid and alkali resistance and ultraviolet resistance. It can be used for waterproofing treatment of special-shaped roofs, repair of old roofs and construction of colorful roofs. It can also be used for bathroom waterproof coatings. . Adding VAE emulsion to cement can not only greatly increase the strength of the cement, but also reduce the voids after solidification of the cement to prevent leakage. Therefore, VAE emulsion can be used to repair concrete and anti-seepage treatment of reservoirs to achieve excellent results. VAE emulsion is mixed with cement and used for laminating tiles and wall tiles. The strong hydration force of the emulsion can prevent the water in the cement mortar from losing too quickly, ultimately achieving excellent bonding strength and excellent durability. In addition, VAE emulsion can also be used as a high-quality interface agent and is widely used in construction and road and bridge construction.
3. Used for high-speed bonding
Continuous production requires fast and efficient bonding. BJ-705 and 706 are designed for high-speed bonding. When the water in the emulsion adhesive not only evaporates but is absorbed into the porous matrix, bonding occurs very quickly. "Fibre tear bonding" occurs just before the last bit of moisture leaves the adhesive. BJ-705 can be used as splice glue, lap glue for high-speed cigarettes and glue for rapid carton prototyping after proper adjustment.
4. Used in disposable tableware and food packaging
According to the relevant regulations of FDA (U.S. Food and Drug Administration), VAE emulsion 705 and 707 are used in food production, manufacturing and packaging. It is safe during transportation, storage and other processes, and is included in the excluded inspections in FDA regulations.
These types of VAE emulsions can not only be used where adhesives are separated from food, but can also be used in places in contact with food. Therefore, VAE emulsion can be used as an adhesive in disposable tableware, paper cups and food packaging industries.
The above uses of VAE emulsion are just a general introduction to VAE emulsion. Due to the wide adaptability of VAE emulsion, users can develop VAE deep-processing varieties suitable for their own purposes according to their actual needs.
As the first VAE emulsion manufacturer in China, Beijing Organic Chemical Factory took the lead in introducing VAE emulsion production equipment from the United States. It currently has an annual production capacity of 60,000 tons of VAE emulsion and is the largest VAE in the country. Emulsion adhesive manufacturer. In recent years, while expanding production scale and improving product quality, we have continuously researched and developed new varieties of VAE emulsions to meet the needs of users from all walks of life and repay new and old users for their support and care for Beijing Organic Chemical Factory over the years.