|Posted by pvac.sales on March 13, 2013 at 2:20 AM||comments (7)|
Carefully distinguish between the nose radome is white, FRP composite material, there is no doubt as proposed. The radar cover the rear of the body and wing are green, yellow, silver-gray tail is the Air Force. Air Force silver-gray ordinary common color, unable to distinguish between the specific material. See the figure, Jian Qi flight test surface is yellow anti-corrosive paint, Jianqi outer skin is aluminum, normal materials. The green part of the front and rear parts of the body should not be ordinary aluminum skin. Contact my previous engineering composites, green and blue-green, which indicates that the front and rear of the body's skin may be carbon fiber, great! Lose weight and durable carbon fiber maintenance performance is very Well! Central body is yellow aluminum skin, but also central for a large part of the force, and composite materials technology is not then cross the border ah! Aircraft engine part is yellow rust, the engine temperature is high, the composite skin is not so good temperature tolerance. Super low shrinkage material PVAC Polyvinyl Acetate also have a significant performance
|Posted by pvac.sales on February 26, 2013 at 2:40 AM||comments (1)|
Polyvinyl Acetate (PVAC) is largely used in SMC technology for Auto panel and Auto lamps. Polyvinyl Acetate used here is as a Low Profile Additive (LPA) to make the surface an "A" Class.
|Posted by pvac.sales on December 12, 2012 at 2:10 AM||comments (1)|
Polyvinyl Acetate Food Grade (PVAC) is produced by USA expired and open patent.which was imported by our joint-venture partner Germany Yinji Group Limited. and invested more than 5 millions in the enterprise.after joint-venture imported new technology and advanced equipments were used.so our output was increased and quality is improved also.
We are the only one manufacturer who can produce Granule form PVAC. including the grades of high.middle and low molecular weight. Granule PVAC for gum base production is produced by whole production line of underwater molding which was imported from other country.
Granule form PVAC is clear crystal without impurity. it is not produced by crush method and do not contain metal scrap particles. Because its small particles and good dispersion.so it is easy for adding in production and save energy
According to the customer demands.Products are divided intoSlice, Crush and Granules. Packing of products are in the plastic bag with carton.high performance to price ratio.and cost saving.
1. Appearance: grain. pieces. particles and flake
2. The content of solid: 100%
3. Acid : < 0.5 (mgkoH/g)
4. Viscosity: 1-12 mpas
5. Molecular weight: 10000-220000
|Posted by pvac.sales on June 14, 2012 at 10:55 PM||comments (2)|
PVAC (Polyvinyl Acetate) Application in Technology of SMC * BMC
SMC and BMC are thermoset, that means crosslinking materials where the crosslinking is irreversible. This is the base for the unique technical performance of these materials class.
The materials consist of the following components:
In difference to most other polymer materials the shrinkage can be controlled and adjusted very precisely by adding LS or LP additives. For highest precision and optimum surface qualities materials with negative shrinkage (= expansion) are composed.
Manufacturer of SMC
SMC composites are made from chopped multi end rowing strand sandwiched between two layers of film, onto the resin paste (resin, shrink compensation, fillers, additives and curing agent) has already been applied. The prepreg passes through a compaction system that ensures complete strand impregnation and makes a sheet wound into rolls. These are stored for pre maturing before moulding to allow the prepreg to thicken into a mouldable viscosity.
Injection SMC is after pre maturing cut into smaller, coreless coils and packed in styrene tight bags, fitting all UP injection moulding machines stuffer units.
Manufacture of BMC
BMC composites are made from a premix, consisting resin, shrink compensation, additives and curing agent which is compounded in special dissolvers, and the reinforcement, consisting of chopped fibres. The final mix and homogenisation is made in different types of kneeders / mixers. BMC is compacted and packed in styrene tight bags in variable size, fitting all UP injection moulding machines stuffer units.
Molding of SMC/BMC
Moulding is made in heated steel tools at temperatures between 125°C and 170°C. It is very important to take note of the setup instructions of each specific material due to the variety of formulations. All known processes are possible as the material will be tailor made for your specific process and application.
Layers of SMC or preformed pellets of BMC are placed into the heated tool. Through closing the tool the material fills the cavity and polymerizes. After complete cure the parts are released hot.
With compression moulding highest mechanical strengths can be achieved.
Preformed SMC or BMC is placed in the injection valve of the heated tool and is injected into the cavity after closing the tool. The material fills the cavities and polymerizes. After complete cure the parts are released hot.
Transfer moulding is used for multi cavity tools of thick parts with high requirements for strength.
BMC or injection SMC are placed in the stuffer which feeds the injection unit. For these thermosets non return valves are used. The Composit is injected into the closed hot tool, fills the cavities and polymerizes. After complete cure the parts are released hot.
Injection moulding is used for highest precision parts and complex geometries.
Injection Compression Molding
BMC or injection SMC are placed in the stuffer which feeds the injection unit. For these thermosets non return valves are used. The Composit is injected into the semi closed hot tool, fills the cavities and polymerizes. After complete cure the parts are released hot.
Injection compression preserves the fibres and improves the degassing of the cavities. The process is used for parts with high mechanical strengths.
|Posted by pvac.sales on May 2, 2012 at 10:55 PM||comments (3)|
The price of polyvinyl acetate (PVAC) is always the key issue that is concerned before purchase. How to evaluate the price of polyvinyl acetate (PVAC) is a significant element that a purchasing manager have to acquired. Here are some clues to help with pricing polyvinyl acetate (PVAC).
|Posted by pvac.sales on April 27, 2012 at 9:50 PM||comments (2)|
polyvinyl acetate (pvac) has large applications in Adhesives. For the application in Adhesive industry, previously the market is widely occupied by Wacker, Synthomer, Sekisui and Colomblia Chemicals, but now with the joining of YY PVAc, the market share is going to change. As the polyvinyl acetate provided by YY PVAC is in equivelent quality and better price, It will take the places of the previous market occupiers.
Polyvinyl acetate (PVAc) (Vinyl Acetate Homopolymer) includes polymers of all molecular weights formed from the free radical polymerization of vinyl acetate monomer. These homopolymers are sold as latex, emulsion, or spray dried solids. The spray dried polyvinyl acetate emulsions can be reconstituted in water, mixed with other adhesive emulsions, or mixed with other dry ingredients, where they have the ability to be used as a binder in dry mix formulations.
The PVAc emulsions are, by far, the major form in which polyvinyl acetate is used in the adhesive market. PVAc emulsions exhibit excellent compatibility with many modifying resins, lending themselves to a broad range of applications through formulation. In addition to compatibility, molecular weight, or grade, and the amount and type of protective colloid used to produce the emulsion affect adhesive properties. Variations in type and quantity of protective colloid used in producing the PVAc emulsion have a major impact on the performance of the adhesive film. Vinyl acetate adhesives that vary from low moisture sensitivity by changing the content and type of protective colloid.
In addition to protective colloids, PVAc homopolymers typically contain functional additives such as wetting agents and plasticizers such as dioctylphthalate or dibutylphthalate. Such modifiers impact adhesion, open times, speed of tack, water resistance and emulsion stability.
There are three major types of stabilization mechanisms used in the manufacture of PVAc homopolymers; polyvinyl alcohol (PVOH), hydroxy-ethyl cellulose (HEC), and surfactants.
Although PVAc films possess good aging characteristics due to inherent inert properties to UV and oxidation, vinyl acetate is hard and water sensitive rendering the films brittle below room temperature. Thus, making PVAc homopolymers inappropriate for exterior uses.
PVAc hompolymers are the lowest cost emulsions while possessing good adhesion to many porous surfaces such as wood and paper.
Packaging and furniture applications involving paper and wood substrates constitute over 90% of the usage of PVAc emulsion adhesives. The balance of the usage involves a wide variety of applications including consumer white glue. The packaging applications include boxboard manufacture, paper bags, paper lamination, tube winding and remoistenable labels. In construction, PVAc is used in prefab construction, including flooring and panel installation. PVAc is not generally used as a primary fastener where great strength is needed.
Alternative systems, such as vinyl acetate/acrylic copolymers and/or vinyl acetate ethylene coplymers (VAE), limit the growth of PVAc in applications requiring properties such as moderate water resistance, flexibility, low temperature adhesion, or specific adhesion to non-porous surfaces, e.g., vinyl or aluminum.
There exists a hurdle rate beyond which PVAc will lose any cost advantage and thus share to VAEs. Historically, this threshold has been a price differential of $0.11 per wet pound vs. VAEs, with VAEs being the higher priced polymers. This resin classification market report on polyvinyl acetate (PVAc) (vinyl acetate homopolymer)estimates 2003 demand with a historical perspective back to 2000 as well as forecasts through 2005 and 2010 within the U.S. Adhesives Industry
|Posted by pvac.sales on April 26, 2012 at 1:00 AM||comments (14)|
Polyvinyl acetate (PVA or PVAc) is a rubbery synthetic polymer with the formula (C4H6O2)n.
Polyvinyl acetate (PVA or PVAc) is a rubbery synthetic polymer. (Homo)polymers are prepared by polymerization of vinyl acetate monomer.
Copolymers are vinyl acetate (VAM) based polymers internally plasticized with for example ethylene (VAE) or acrylic (VAA).
Polyvinyl acetate is also the raw material to make Polyvinyl alcohol. Polyvinyl acetate is partially or completely hydrolysed.
Polyvinyl acetate was discovered in Germany in 1912 by Dr. Fritz Klatte. On an industrial scale, vinyl acetate is produced from ethyne, ethanoic acid and a mercury(I) salt.
The degree of polymerization of polyvinyl acetate typically is 100 to 5000. The ester groups of the polyvinyl acetate are sensitive for alkali and will slowly convert PVAc into polyvinyl alcohol and acetic acid.
Under alkaline conditions, boron compounds, such as boric acid or borax causes the polymer to cross-link forming tackifying precipitates or slime.
Applications and uses
As an emulsion in water, PVAc emulsions are used as adhesives for porous materials, particularly for wood, paper, and cloth, and as a consolidant for porous building stone, in particular sandstone. Uses: as wood glue PVAc is known as "white glue" and the yellow "carpenter's glue" or PVA glue.
in paper converting as fast binding adhesive
in bookbinding and book arts due to its flexible strong bond and non-acidic nature (unlike many other polymers).
for handcrafted works.
To a lesser extent PVAc emulsion are used in paper coatings, paint and other industrial coatings. PVA can also be used as coating to protect cheese from fungi and humidity.
Translation of "Polyvinyl acetate"
Czech: Polyvinylacetát, German: Polyvinylacetat, Estonian: Polüvinüülatsetaat, Spanish: Acetato de polivinilo, French: Polyacétate de vinyle, Indonesian: Polivinil asetat, Lithuanian: Polivinilo acetatas, Malay: Polivinil asetat, Dutch: Polyvinylacetaat, Japanese: ポリ酢酸ビニル, Polish: Poli(octan winylu), Portuguese: PVA, Russian: Клей ПВА, Swedish: Polyvinylacetat, Chinese: 聚醋酸乙烯酯.