As consumption patterns have changed due to economic growth, packaging materials have also become increasingly diversified, with an accompanying improvement in quality. Pearlized films and synthetic paper used for various kinds of labels and packaging materials have followed this trend, becoming more diversified and improved in quality in response to increasing demand. Synthetic paper is an especially promising material. Although more expensive than natural paper, it has many applications including outdoor advertising materials, sterilized packaging materials and damp proof labels, etc, in that it has good durability and damp proof and can be recycled.
Manufacturing principle
[Definition of cavitation in film] Fillers are added to plastic resin, sheets are formed through casting a process and then MD stretching and TD stretching are carried. At this point, the interface between filler particles that are finely spread and the plastic resin is opened, it forms fine pores (cavitations) which interconnected in three dimensions. This forms a porous structure, lowers the specific gravity and shows a milky white color by dispersing light.
Film History
A. Pearl Film This film is produced filled with CaCO3 M/B, using PP (Polypropylene) as the main material, which shows a pear tone. For that reason, it is called pearl film.
B. Synthetic Paper Synthetic paper means "synthesized paper" in which paper made originally from pulp (wood) is produced using synthetic resin as a main material obtained from petroleum and appears to be common paper made from pulp That is, common synthetic paper can be defined as "plastic paper that is produced from synthetic resin, but has also characteristics of paper produced from pulp, so can be processed in various applications".
Fogging is a condition in which water vapor is discontinuously condensed in the form of small water droplets.
A. Fogging on a film surface Plastic film is hydrophobic, so when packaging food, water contained in the food is evaporated and sticks to the inside of the packaging and makes it opaque. Generally, when liquid touches the surface of solid, it does not spread but forms a drop.
B. Conditions under which fogging forms on a film surface
- When the temperature inside the film falls below the dew point of the mixture of air and water vapor
- When the air temperature around the film is too cool to allow absorption of water vapor.
Packaging food at room temperature ¡æ Keeping it cold (4¢ªC) ¡æ below dew point with water vapor saturation ¡æ Condensation on film surface
Anti-Fogging Mechanism
Water has a surface energy as high as 72mJ/m2 and tends to form a spherical shape, which is the most stable form. Therefore, when the surface tension of the material to touch water is low, spherical water drops are formed. By contrast, when the surface tension is high, water is spread broadly.
A/F additives that are applied to inside are surfactants and are not compatible with polymer. When a film is produced, an A/F agent is uniformly dispersed into the entire film and transferred to the surface, increasing the critical wettability. Such a phenomenon, in which the difference between polymer and water is definitely decreased, occurs at the same time when water is partially dissolved to decrease the surface tension of water. As a result, the contact angle between the surface of the polymer and the water decreases causing the water to spread more uniformly, thereby reducing the opacity caused by the formation of water drops. There is also a "reservoir" effect in which you can use the film longer by adding A/F agent to the inside of the film and distributing it uniformly, maintaining the concentration of the A/F agent.
Effects of fogging
A. Agriculture
When the contact angle (¥á) is large, part of the light is reflected back due to internal total reflection and average light transmission is rapidly decreased.
- Decrease in growth rate of plants
- Decrease in yield
- Delay of ripening of crops and thus time of sales
Water drops function as a lens, focusing penetrated light (or heat) on weak plant tissue
- Burning crops
- Damage to crops
B. Food packag
When the film is used for packaging food, especially when exhibiting the contents or keeping it cold
- Decrease in transparency lowers purchase appeal
- The quality of food appears to be poor
- Water is gathered in a certain part of the package, which may cause food spoilage
Characteristics of H.S.I anti-fogging film
A. Good fogging ability and maintenance of freshness H. S. I anti-fogging film has a good ability of fogging and does not cause dew condensation, thus preventing propagation of putrefying bacteria caused by condensed water, and helping to maintain freshness
B. High transparency H.S.I anti-fogging film has a high degree of transparency and makes the packaged food appear fresh, increasing the effect and value of its display.
C. Excellent Heat-sealability H.S.I anti-fogging film is heat sealable on one side or both sides, and has a good heat-sealing property for its high heat sealable intensity.
D. Excellent anti-static property
What's heat sealing?
Heat sealing is a phenomenon in which a molecular chain on one side of a film is contact melted for a certain length of time above the softening point of the film, and spreads to the other side, bonds with other molecular chains and solidifies (crystallizes), resulting in fusion of the films. In this state, the interface of the film loses its original nature and cannot be separated. This phenomenon is called heat sealing.
Principle
A. Surface sealing Bonded is achieved by intermolecular force on the film surface, brought about through the momentary contact. (The strength of the bond depends on the intermolecular force and contact area)
B. Fusion sealing The film is fused when a molecular chain on one side of a film is contact melted for a certain length of time above the softening point of the film, and spreads to the other side, bonds with other molecular chains and solidifies.
Types
Optimal heat sealable condition
Characteristics of H.S.I heat sealable film
Heat sealing properties are very important, as even small defects in heat sealing may cause fatal defects in products. H.S.I heat sealable film has excellent heat sealing properties and we manufacture a diverse range of products, so you can choose one according to your intended use.
A. One side Treatment, One side Heat sealable
- HO801 : Good heat sealable properties at low temperature
- HO271 : Good heat sealable properties, good stiffness and suitable for machining and printing
- HP431 : Elegant appearance with a transparent pearl tone Good heat sealable properties at low temperature, suitable for printing, and good opaque properties
- HO681 : Good stiffness, good slip properties, and metallizable film
- HO691 : High elongation, good heat sealable properties, and metallizable film
B. Non-treated, Both sides heat sealable
- HZ800, HT800 : Good hot slip properties, suitable for high-speed machine, and good anti-static properties, and good optical properties
C. One side Treatment, Both side Heat sealable
- HT801 : Good printing property
D. Both side Treatment , Both side Heat sealable
Patent
Registration No. 0367114 : Biaxially oriented polypropylene film for fluorescence sensor and process for preparation thereof
What is "metallizing"?
Heating metal in a vacuum ¡æ evaporation of metal ¡æ Brownian motion of metal ¡æ condensation on the material in a vacuum. Metals such as Al, Zn, Si, Pt and oxides like SiOx, AlOx are used.
Principles and characteristics
Method
Contents
Chemical method of forming thin layer
Spray
Chemical Vapor Deposition(CVD) : APCVD, LPCVD, PECVD, EPITAXY, MOCVD
SOL-GEL
DIPPING
Physical method of forming thin layer
Vacuum evaporation
Sputtering : DC, PF, DC Magnetron, RF Magnetron, BIAS, Reactive
ION Plating
A. Physical method - Evaporation : There are thermal evaporation methods in which metal is heated and evaporated in a vacuum and electron beam evaporation methods in which electrons are accelerated by thousands of volts between metallized materials and filaments and are collided with the metallized materials, changing kinetic energy to heat energy. Evaporation is performed under low pressure, below 10-5 Torr, and metals or various kinds of materials are used for coating. Evaporation has a high thin layer formation rate, its contact intensity is low and it is not suitable for producing small and uniform thin layer. Especially, the substrate coverage is low for direct motion of evaporated molecules.
- Sputtering : Sputtering is a phenomenon in which particles with high energy are collided with a target material and the target material emits atoms or molecules. On the assumption that the target pole is the negative (-) pole and the substrate is the positive (+) pole, when high voltage is applied under 10-2 Torr of Ar gas, Ar gas around the negative (-) pole is ionized to become Ar+ and collides with the negative (-) pole. Molecules or atoms coming out in the ion impact stick to the substrate of the positive (+) pole, forming thin layers. n sputtering, metals, metal compounds and insulators can easily form thin layers. They have high energy, so the adhesive force of thin films and coverage are good, but formation of thin layers is slow.
B. Chemical method(CVD: Chemical Vapor Deposion) In this method a substrate is coated with metals, carbides, nitrides, or sulfides by gas reaction. Halogen compounds like chlorides are used for the reaction, and H2 or a mixed gas of N2 and hydrocarbon is used as the carrier or reaction gas. These reacted materials are vaporized from a vaporizer, sent to a treatment chamber with the carrier gas, and reacted on the substrate surface, which is heated to high temperature, separating coated materials.
- Atmospheric Pressure Chemical Vapor Deposition (APCD) : In one method, thin layers are metallized by chemical reaction of heat energy in a reaction vessel under normal pressure.(760 Torr) It consumes much gas and exhibits a high proportion of defects, but also results in a high metallizing ratio even at low temperatures. (400-500¢ªC)
- Low pressure Chemical Vapor Deposition (LPCVD) : It In another method thin layers are metallized by chemical reaction of heat energy in a reaction vessel under low pressure (0.2 - 2.0 Torr). It uses high temperature (300-900¢ªC) and exhibits a low metallizing ratio, but the purity of the metallized films is high and results are uniform.
- Plasma Enhance Chemical Vapor Deposition (PECVD) : There is also a method in which thin layers are metallized through a reaction in which electrons obtaining high energy from electricity are collided with molecules of neutral gas, decomposing gas molecules and the decomposed molecules stick to the substrate. Metallizing occurs under low pressure (0.1-5 Torr) and at low temperature (200-500¢ªC) and reaction time is short, but there are problem related to impurities.
Purpose of metallizing
A. Giving barrier property
The most important function of a packaging substrate is to protect the packaged materials. Therefore, food and electronic materials sensitive to air and moisture need to be protected from them. Metals used in metallizing, such as aluminum, function as a barrier and for that reason it is used for packaging materials like food and electronics.
B. Optical property
Generally, plastic films exhibit a low ability to reflect light, but tend to transmit it, while Aluminum metallized films do not transmit light but reflect it, having a glossy surface. For that reason, they are used for packaging presents or agricultural products.
C. Surface conduction
The largest problem with plastic films is that they cause static electricity, but Aluminum metallizing has the property of conduction, which prevents static electricity on the metallized surface.
D. Electromagnetic wave prevention
In metallizing, metals are usually used, which blocks electromagnetic waves.
E. Heat Stability
Plastic films are transformed at a relatively low temperature and the film itself is melted, but for Aluminum heat transformation occurs above 800¢ªC.
Main factors in the metallizing process
A. Temperature
High temperature and heat stability are needed for heating and evaporating metals like Aluminum, and a cooling process is also needed. For Aluminum, 900-1300¢ªC is needed. B. Vacuum
It is very difficult to heat and evaporate metals like Aluminum; evaporation can be achieved through lowering vapor pressure. The vacuum facilities are as follows. (Less than 10-4 Torr)
- Rotary Pump : A method in which a vacuum is formed by pumping air inside of the evaporator to the outside
- Diffusion Pump : A method in which a vacuum is formed by heating the air, so that air inside of the evaporator can be pulled out more easily
- Poly Cold : When the inside of the evaporator where the vacuum is formed contains moisture, as well as air, the degree of vacuum is lowered and metallized films are not formed uniformly, so it is necessary to remove them. Poly-cold facilitates by condensating of water vapor by rapid cooling and is used for resolving the above problem. About -100 ~ -150¢ªC C. Cooling R/L
When metal gas is metallized onto a film surface that is coated, high temperature of heat occurs and a cooling process is required. (-25 ~ 20¢ªC) D. Tension
To metallize films uniformly, it is necessary to use an R/L (Expander R/L or banana R/L and Grooved R/L) that maintains the appropriate tension and flattens the film.
Characteristics of H.S.I metallized films
A. For packaging presents(HM131)
Used for packaging presents as it displays a fine gloss and good slip properties, and good Al bonding strength.
B. For packing food
Snacks in which oils and fats are processed or spice is added are deteriorated by moisture, light and extremes of temperature. Therefore, protective packaging is needed.
- HM191 : High elongation, good heat sealable properties, good Al bonding strength and good prevention of moisture and air penetration
- HM181 : Good heat sealable properties, good slip properties, good tearability, and good Al bonding strength
C. For agriculture(HM121)
With its reflection properties, it is used for maximizing irradiation of light and improving concentration of fruits in orchards; it exhibits a fine gloss.
What's breathable film?
Breathable films have a structure in which continuous pores are distributed inside of the film, and the pore size is less than a few§. It is a representative functional film that has functions of both vapor permeation and waterproofing, whereby air and water vapor permeate, but water drops do not.
Manufacturing processes for breathable films
A. General methods
Classification
Large classification
Small classification
polymer porous films
Melting process
extraction method, foaming method, stretching method, electron beam irradiation method
B. Stretching method The main materials used in the stretching method are polyolefin resin, inorganic fillers and various kinds of additives. These materials are mixed very uniformly and processed into pellets, and these pellets are then processed into sheets through extrusion molding and stretched through a special process, which causes cracks between the resin and inorganic fillers and thus forms continuous and uniform pores, manufacturing breathable film that has both functions of vapor permeation and waterproofing.
Structure, functions and effects of breathable film applied by stretching method
A. Structure
Breathable film processed using the mono axially oriented method has a one-layered structure in which pores are formed continuously and uniformly. Resins are oriented in the direction of stretching through the stretching process, and pores are also shaped in an oval form that is expanded in the direction of stretching. In addition, the surface of these breathable films becomes rough through the formation of pores and special micro-embossing treatment, and their cross section has a structure in which channels are formed whose upper and lower parts are interconnected by continuous pores that allow vapor, air and gas to pass through.
B. Function
- The most representative function of breathable films is vapor permeation and waterproofing in which air and water vapor pass through but water drops do not, due to the continuous and uniform fine pores.
- Mechanism and model of vapor permeation
Classification
fine pore
water vapor
water drops
pore size(§)
0.1~10
0.00001~0.0001
100
C. Role and effect of breathable film in diapers - Lowering temperature and humidity inside of diapers by the function of vapor permeation of breathable films
Dermatitis may be caused by various kinds of bacterial growth fostered by the increase of temperature and humidity inside of diapers. It is necessary to down the temperature and humidity inside of diapers in order to prevent dermatitis. When breathable films are used in diapers, water vapor is discharged to the outside of the diaper through fine pores that are formed over the cross-section of the film, lowering the humidity and temperature by vaporization, which checks the growth of various kinds of bacteria and prevents dermatitis.
Laminating products
Combining the functionality of breathable films with characteristics of other materials, applications in new industrial fields with various kinds of laminating processes are increasing. For diapers, compound products are being developed in which breathable films and non-woven materials are laminated, giving both the feeling of non-woven fabric and the functionality of breathable film.
Properties of breathable film
A. Waterproofing properties
Step
Kind
Use
Test Method
1
material penetration
solid compound, criterion of resistance against penetration of sprayed materials
ASTM F1215
2
Liquid penetration
criterion of resistance against penetration of liquid
Measurement of hydrostatic head(AATCC 127, ISO811, JIS L-1092) Evaluation of liquid repulsion(ISO 6530, EN 368) Evaluation of liquid penetration(ASTM F903, ISO 13994)
3
Penetration of mixed solution (blood, urine)
criterion of resistance against penetration of vapor, medical industry(related to blood)
ASTM F1670
4
Virus penetration
criterion of resistance against virus penetration
ASTM F903, F1670, F1671
B. Functionality
Kind
Use
Test Method
Water vapor transfer rate
criterion of evaporation of vapor
ASTM E96(Water/Desiccant method), JIS Z 0208(KCL method)
D. Other special property UV Stability, Flame retardance, Decrease in surface resistance or static charge
Use of breathable products
Kind
Use
Required property
Structure
For hygiene/diaper
diaper
WVTR, tear strength, tensile strength
breathable film + materials for diapers
House Wrap
prevention of moisture-prevention of dew condensation-blocking cold air
hydrostatic head, tensile strength of a break, tensile strength, WVTR, flexibility, resistance to air flow, durability
breathable film + PE gunny bag breathable film + PET, PP non-woven fabric
Industrial protection clothes
removing asbestos, pollution treatment and disposable working clothes
WVTR, waterproofing, liquid pollution prevention, air permeation, prevention of particle penetration
breathable film + PP non woven fabric, SMS Spunbonds Tyvek (Dupont NWF)
Leisure clothes
sox, town wear, clothes preparing for odorous atmosphere
WVTR, waterproofing, toughness
Gore Tex laminate PTFE film + monolithic hydrophilic polyurethane
Bedding
prevention of various kinds if harmful viruses and ticks in bed, furniture, and pillow
WVTR, water resistant, prevention of viruses penetration, Softness, air permeability, defense of particle
breathable film + SBW non-woven fabric
Roofing Membrane
prevention of heat loss on a roof, discharge of moisture, and prevention of dew condensation
WVTR, tear strength
breathable film +high basis weight and flame retardant SBW non-woven fabric breathable film +high-strength PE gunny bag
What's "laminating"?
It means a process in which printed paper and films are adhered to each other with adhesives or heat sealable resin, to perform various functions.
What are "adhesives"?
Adhesion is an operation in which the same or different kinds of solids are adhered by adhesive force of materials (mainly intermolecular forces) to show the properties necessary for the materials (e. g. physical strength). Adhesives are the materials used for adhesion. The most important property in adhesives is adhesive force, and the adhesive force is measured from breakage resulting from a load applied in the adhesion field, as in Figure 1-1. Such broken areas generally have three parts, as shown in Fig. 1-1. Breakage at ¨ç is called as a cohesive failure in adhesive layers, breakage at ¨è is called as a adhered interface failure and breakage at ¨é is called as a cohesive failure of adhered materials. When applied to adhesion field, breakage occurs at the most weak place, but failure of adhered interface cohesive failure and cohesive failure of adhesive layers are caused by misuse of adhesives.
¡Ø Requirements for adhesives Requirements for adhesives are as follows Should be liquid, Should make adhered materials wet, Should be solidified during adhesion process
Kind and process of paper lamination
A. Dry lamination
B. Wet lamination
Purpose of lamination
A. Increase in value of appearance
B. Improve durability
C. Protect contents
D. Increase quality and differentiation
Kinds and characteristics of paper lamination
A. Kind of film for laminating paper
- Clear lamination film : Products suitable for laminating application that exhibits an elegant appearance and good gloss by increasing transparency and surface gloss.
- Matte lamination film : Products suitable for laminating application that exhibits matte effect, with high opacity and low surface gloss.
B. Characteristics by kind
Section
Clear laminating film
Matte laminating film
Characteristics
good gloss effect
good matte effect (faint effect)
good slip properties
good slip properties
good anti-static properties
good prevention of static electricity
suitable for printing, good workability of lamination
suitable for printing, good workability of lamination
good adhesion
good adhesion
-
UV coating available
Main use
Section
Clear lamination film
Matte lamination film
Main use
Covers of publications (books, magazines, catalogues)
Commercial prints (posters, calendars, catalogues)
-
Matte transcription
Outline
In the past, we used emery paper roughed from lumber or coating film to grant non- lustrous effect to decorative material. But after Matte film, excellent in cost and time saving aspect, was developed, the lustrous effect granting method by transcribing is generalized. In case of Matte Pet film, it is superior in heat resistance so work can be done in high te mperature. Also it is superior in abrasiveness thus showing no respond to outer friction.
Synthetic paper which made out of BOPP and Biaxially Oriented Polypropylene Film doesn't have the defect that paper has (for example: ripping, weak in water and others) and it has the printing ability and post processing ability through appropriate manufacturing process. It also has skill with plastic such as intensity, waterproofing, ¡°weatherability¡±, measurement stability, smoothness, dust-proof, moisture proof, oil resistance, and impact resistance. Synthetic paper is manufactured using Polypropylene synthetic paper produced from petroleum and inorganic matters. It is similar to natural paper, pulp, and plastic film thus used very widely. It will be used as substitute for natural paper.
Manufacturing method of synthetic paper
Synthetic paper has characteristic of both film and paper and its main material is Polypropylene. It is manufactured generating micro-void adding inorganic bulking agent. The structure of synthetic paper consists of both a ground layer and a material layer. And it goes through double drawing process in Machine Direction and Transverse Direction. In the material layer of synthetic paper forms enormous micro-void through two drawings and by this micro-void, the low gravity and low light transparency is granted.
Merit of Synthetic paper and superior property of matter
Section
natural
film
synthetic
others
Intensity
¡Ü
¡Ü
Excellent in tensile strength, bursting and impact intensity and durability.
water resistance
¡Ü
¡Ü
Due to water-proof plastic as main material, the water resistance is great and there is no change in intensity and measurement in humid conditions.
folding endurance
¡Ü
¡Ü
appropriate for map sheet which is folded repeatedly.
printableness
¡Ü
¡Ü
With the special coating process, you can get clear printing and almost all printing method can be applied.
oil and chemical resistance
¡Ü
¡Ü
has tolerance to acid, alkali, organic solvent, oil and others.
lightness
¡Ü
with influence of micro-void, it weighs 2/3 of natural paper.
weatherability
¡Ü
¡Ü
no change intensity and appearance in ultraviolet rays, rainfalls.
Product Introduction
Section
Usage
Representable Grade and others
General Grade
general synthetic paper Grade
HU532, WG102, WS102, UV102(202)
Coating Grade
Improved printing ability Grade
HU201, WG201, WS201
Special Grade
Granted functions through special coating Grade
TS201, HU, UM101(201)
Detailed introduction of Product
A. General Grade
Section
Thickness
Usage
Trait
HU532
60, 80, 90
For header
excellent stiffness
WG102
80
for tacky adhesion label
excellent stiffness superior whiteness and sequestration
WS102
80
for tacky adhesion label
superior sequestration, electric charge resistance Semi-Matte product
UV102/UV202
30
For Duct Wrapping
excellent UV stability metalization possibility UV102(a face matte), UV202(double face matte Type
PL102
60, 80
for POP, for tacky adhesion label
High Yield(25.6m2/Kg) superior sequestration
B. Coating Grade
Section
Thickness
Usage
Trait
HU201(2)
60, 80, 90
For tacky adhesion lable, POP, Tag, map and others
superior stiffness excellent in printableness (offset printing, UV offset printing is possible) HU201(inner side coating product), HU202(double face coating product)
WG201
80
superior stiffness superior whiteness and sequestration excellent in printableness (offset printing, UV offset printing is possible)
WS201
80
superior sequestration, electric charge resistance excellent in printableness (offset printing, UV offset printing is possible)
C. Special Grade
Section
Thickness
Usage
Trait
For ink jet
-
For photo printing paper for ink jet printer
excellent printing ability and color expression superior water resistanc
TS203
80
For thermal paper
excellent color make and color make stability superior stiffness and sequestration
UM102/UM202
30
For Duct Wrapping
A metal product excellent Barrier
Usage of synthetic paper
Section
Trait
Applying usage
General printing
intensity, durability, whiteness, printability
out-door poster, back light poster, banner, pamphlet and others
publication
water-proof, smoothness, printability, electric charge resistance
product manual, children's book, index chart, calender, menu and others
map
smoothness, chemical resistance, water-proof, folding endurance
It is ideal for specialized map production such as tourism map, topographical map, route map, military map, marine chart and others.
label and tag
printability, water-proof, recycle, stiffness
general label and airline luggage tag and others
thermal paper
chemical resistance, smoothness, dust-proof, durability
printing paper, blueprint paper, clean-room paper, tracing paper, thermal paper and others
For OA and others
smoothness, water resistance
ink jet paper, photo printing paper and others
Properties of matter chart
Section
Download the properties of matter chart
General Grade
HU532, WG102, UV102(202), WS102
Coating Grade
HU201(202), WG201, WS201
Special Grade
For ink jet, TS102, UM101(201)
Patent status quo
Registration No
Title
10-0263021
Polypropylene synthetic paper and producing method
What is cavitated film?
