New technology: polyvinyl alcohol (PVA) film
The density of the polyvinyl alcohol film is 1.26-1,29g/cm cubic, the refractive index is 1.52, and it emits white light after ultraviolet radiation. It has high water absorption and can be dissolved in water. The moisture content of the fiber can reach 30%-50%, and the moisture content can reach 4.5% under the environment of 65% RH and 25 ℃. It can permeate water vapor, but is difficult to permeate alcohol vapor, let alone organic solvent vapor, inert gas and hydrogen. The barrier properties of polyvinyl alcohol film are even better than vinylidene chloride film.
Definition of polyvinyl alcohol film
Polyvinyl alcohol (PVA) [1] is a water-soluble polymer, which is characterized by good density, high crystallinity, strong adhesion, flexible and smooth films, oil, solvent, abrasion, and gas resistance. It has good permeability and water resistance after special treatment, so it has a wide range of uses.
Polyvinyl alcohol is non-toxic, tasteless and harmless to the human body, has good affinity with the natural environment, does not accumulate, and does not pollute.
Polyvinyl alcohol film is a green and environmentally friendly functional material that is mainly made of polyvinyl alcohol, added with modifiers and other additives, processed by a special process, and can be completely degraded by microorganisms in the soil. It can be degraded into carbon dioxide and water in a short time, and has the effect of improving the land.
The biggest advantage of polyvinyl alcohol film is water solubility, and the biggest disadvantage is poor water resistance. The poor water resistance is due to the hydrophilic hydroxyl (-OH) in the molecule. If the hydroxyl group can be properly blocked and water-resistant groups can be attached, the water resistance of the PVA film can be improved. PVA contains hydroxyl groups, which can undergo a typical reaction of polyols. If appropriate polycondensate is selected, it can interact with the hydroxyl groups in PVA to form a strong three-dimensional structure. Stabilize the air tightness of VA under wet conditions and improve the water resistance.
classification
Polyvinyl alcohol films are divided into the following categories according to their solubility characteristics:
Room temperature soluble film (NT type, also known as fast soluble film, cold soluble film): Dissolving temperature 25℃
Medium temperature soluble film (IT type, also known as medium soluble film, hot melt film): Dissolving temperature 65℃
High temperature soluble film (HT type, also known as insoluble film, resistant to soluble film): Dissolving temperature 85℃
Special film: formula and process can be designed according to specific use to meet the requirements of special use.
performance
1 Environmental protection
PVA film products are green materials料. Relevant departments have measured that the biological oxygen consumption of PVA (BOD) is much smaller than that of starch. Five days after Airvol's PVA products were put into the biological solution by Air Products, the measured BOD was less than 1% of the original BOD total. Biological tests prove that PVA is neither toxic.
As far as the decomposing machine is concerned, PVA material has two decomposing properties: water and biology. It first dissolves in water to form a glue and penetrates into the soil, which can increase the soil's mass adhesion, air permeability and water retention, and is especially suitable for sandy soil reconstruction. The PVA material in the soil can be decomposed by bacteria in the soil, and finally can be decomposed into CO2 and H2O.
2 Water solubility
The solvent of PVA is water, but its solubility in water is greatly affected by polymerization, especially by alcoholysis. When alcoholysis 度 is below 88%, it is almost completely dissolved in water at room temperature at 20℃. As the alcoholysis 度 rises, it dissolves 度 significantly 度 down降, and the completely alcoholysis PVA dissolves in water very little.
The water solubility of PVA film is related to the thickness 度 of the film and the temperature 度 of the water. The relevant data table is as follows:
Dissolving water temperature Start dissolving time
(Minutes) complete dissolution time
(minute)
Room temperature soluble film 25℃ 0.5 15
Medium temperature soluble film 65℃ 0.5 10
High temperature melting film completely melted below 40℃, completely dissolved above 85℃ 0.5 10
Note: 1. Film thickness 度: 20μm, 2. In turbulent water.
3 Strength and weather resistance
PVA film has good toughness, high tensile strength, high tear resistance, and ranks first among all kinds of films. Its bidirectional tensile strength is superior, good weather resistance, and long service life. The strong performance of various films is as follows:
PVA film PT film (cellophane) PE film PP film PVC film
拉Strength 度 (MPa) 44.1~63.7 54.9~131.4 17.3~19.1 45.1~53.9 20.6~17.6
Extension率 (%) 150~400 15~25 50~600 200~600 5~25
4 Mold release and metal plating
PVA film has low affinity for highly hydrophobic plastics, and has good release (peeling) performance for various organic materials with low polarity.
PVA film can be aluminum-plated under a vacuum of 1.33×10~266×10Pa, and the product will be peeled off when the product is immersed in water at 30°C for 24 hours.
5 Transparency and gloss
The transparency and gloss of PVA film are better than other films.
PVA film PT film (cellophane) PVC film PET film
Through 率% 90.1 60.5 50.4 57.8
Reflection率% 81.5 60.5 79.5 22
6 Moisture permeability
The moisture permeability of PVA film is similar to that of cellophane. It is a kind of film with extremely high moisture permeability. When packaging hot and wet items, it will produce mist. The data measured according to JIS-Z1503 are as follows:
PVA film PT film (cellophane) PVC film PET film
Moisture permeability度 1500~2000 1300~2000 120~180 35~180
7 Barrier
PVA film has excellent oxygen barrier properties under dry conditions, and its oxygen permeability coefficient is the lowest among various resin films.
There are large hydroxyl groups (-OH) on the molecular chain of PVA. These hydroxyl groups and water molecules form hydrogen bonds in a humid environment, which leads to changes in the structure of the PVA aggregate state, which greatly reduces the barrier properties of PVA. As the relative humidity 度 rises, its oxygen transmission 量 increases significantly.
PVA film has strong permeability to moisture and ammonia, but has excellent barrier properties to oxygen, nitrogen, hydrogen, helium, argon and carbon dioxide. The barrier to oxygen under normal pressure environment is about the usual poly 1000 times of vinyl film, 300 times of polypropylene film. The use of PVA film can keep the ingredients of the packaged product and its own smell intact.
8 Anti-static
Many plastic films have strong chargeability, while PVA films are almost static. In the process of packaging products with PVA film, 不 will cause its plasticity 降 low or electrostatic dust due to static electricity.
PVA film PT film (cellophane) PVC film PE film PET film
Static voltage 1.2V 1.3V 40.5V 98.6V 120.6V
9 Printing performance
PVA film has excellent water color and ink printability, which is the advantage that the existing plastic film can only be printed with ink. It can be used for water transfer printing, such as: glass, ceramics, electrical housing, automobile parts, etc. Irregular surface Color printing. At the same time, the PVA film has strong polarity and can be used for electric sparks during printing. It is also widely used in special printing industries, such as water transfer film substrates.
10 Heat sealability
The water-soluble packaging film has good heat sealing properties and is suitable for resistance heat sealing and high frequency heat sealing. The heat sealing strength is related to conditions such as temperature, humidity, pressure, and time, and is generally greater than 200g/cm2.
11 Oil resistance and solvent resistance
PVA film has excellent oil resistance (vegetable oil, animal oil, mineral oil), resistance to organic solvents and carbohydrates. However, strong alkalis, strong acids, chlorine free radicals and other substances that can chemically react with PVA (such as borax, boric acid, certain dyes, etc.) are suitable for PVA film packaging.
A Grease absorption量表
Oil test conditions PVA PET OPP PE OPS
Gas oil 20℃, 10 days 0 1.1 1.1 4.7
Diesel oil 40℃, 30 days 0 3.2 5.2 3.5 2.8
Color oil 40°C, 30 days 0 1.8 3.1 4.6 1.5
B Solvent absorption量 table
Solvent PVA EVAL CPP OPP PET
Toluene 3 120 3740 6120 670
Isopropyl alcohol 80 3440 600 430 1070
Ethyl acetate 10 240 2950 3700 1520
Methyl ethyl ketone 7 500 2070 2790 1560
Total amount 100 4300 9360 13040 4820
12 Fragrance retention and sublimation prevention
PVA film has excellent fragrance retention and prevention of sublimation of the package. The use of PVA film packaging can only maintain the fragrance of the package, and it can also prevent the package from being affected by external odors.
Fragrance retention test table
Contents Rose flavor (1ml) lemon flavor (1ml) apple flavor (1ml) wind oil essence (1ml) soy sauce (2ml) 茶 leaf (3g) cigarette (3g)
PP
(25μm) 1 hour 1 hour 1 hour 1 hour 3 hours 1 day 1 day
PP/PE (65μm) 3 hours 1 day 1 day 1 hour 1 week 1 week 1 week
PVA/PP (32μm) 1 week 1 week 1 week 2 days 4 weeks
Above 4 weeks
Above 4 weeks
the above
1 Fast dissolving film
Pesticides and chemical products are packed in lining bags, which can avoid touching the pesticides and chemical products by hand, and there is no residual pesticide in the plastic bag.
Cement additive packaging bag to avoid dust flying and harm the environment.
Embroidery substrates, wigs and other fabric carriers. Set off the carrier for easy cleaning.
Artificial marble release film, with a water-soluble film in the molded film, which can be released quickly.
Water transfer printing, after printing on the film, it can be transferred to the curved surface.
Seed bags, pack the seeds at regular intervals and then bury them in the ground, saving valuable seeds and eliminating the busy thinning.
Wash the packaging bags in the hospital, and put the packaging bags directly into the washing machine without touching the contaminated clothes.
Garbage bags.
2 Medium soluble film
Food, cosmetics packaging bags, supermarket shopping bags.
Food packaging composite film, high-end textiles, plastic bags, packaging cushions.
Use cellophane type printing ink 便 to get beautiful printing effect.
The packaging of animal oil, vegetable oil, mineral oil and the packaging of fat food.
Used for packaging and sealing tea, coffee, curry powder, chili powder, pepper powder and other spices.
It can be used in the packaging of small grains, oil, dried seafood, precious Chinese medicinal materials, tobacco, etc. It can be used in conjunction with deoxidizer or vacuum, and its anti-mildew, anti-moth, and anti-fading quality and freshness.
Anti-static packaging for electronic products.
3 Insoluble film
Sealing of clothing, shoes and hats, leather and leather products, arts and crafts, manuscripts, files, and supporting use with deoxidizers, it has the effects of preventing mildew, insects, and oxidation and discoloration.
Use cellophane type printing ink to get beautiful printing effect.
Packaging of alcohols, ethers, ketones, esters, chemical raw materials and intermediates.
Daily necessities, medicine, toy packaging.
It is used for the sealing of radio components and complete machines, precision machinery, ordnance, 雷da, and ammunition. It has a unique anti-oxidation and corrosion function.
Optical instruments, lenses and spare parts are sealed in a comprehensive way to prevent mold and fogging.
4 Special film
Polyvinyl alcohol film can also be used in special fields such as polarization mode, automobile film, windshield interlayer, and sanitary material manufacturing.
We offer patented full biodegradable film and PVA bag, all products are made by casting equipment, It is different from traditional blow molding products, all blow molding products are non full biodegradable. We can produce pva films and bags in full transparent and various colors. and the PVA film is more smooth than the traditional blow molding products.
We also offer organic material full biodegradable film and bags with patented raw material and production Process.
For more PVA film and bags products please visit us:
http://www.joyful-printing.net/pva-bag/
http://www.joyful-printing.com/pva-bag/