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Procedure Instruction of Pre-Laminating Polyvinyl Butyral PVB Interlayer Film

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Technical Induction of Polyvinyl Butyral PVB Interlayer Film

By Peter Shin www.HelloGlass.com
Polyvinyl Butyral PVB Interlayer Film

Polyvinyl butyral PVB interlayer film is the resin that compounded
from polyvinyl alcohol reacted with butyraldehyde.  Polyvinyl butyral
PVB interlayer film is usually implied in the situation that needs
strong binding, toughness and flexibility. Polyvinyl butyral PVB
interlayer film as a protective interlayer film, is often used to make
automotive laminated glass and architectural laminated glass.
Polyvinyl butyral PVB interlayer film has many properties: Impact
resistance, great adhesion, sound control, UV-radiation filtered, and
good aging resistance.
Technical Parameters of Polyvinyl Butyral PVB Interlayer Film
Note: Following data is general number of PVB Film, and the data may
be different of different Polyvinyl Butyral manufacturers, because the
formula of manufacturing Polyvinyl Butyral may be different.
Property Items PVB
Density 1.069g/cm³
Tensile Strength ≥ 20MPa
Elongation  ≥ 200%
Visible Light Transmission Rate 88.5%
Haze ≤ 0.4%
Ultraviolet Radiation Blocking Rate 99%
Weather Resistance
(85℃,85% Humidity,UV,1000 hrs） Moisture Absorption  0.4-0.6%
Shrinkage  High Temperature Resistance Qualified
Moisture Resistance Qualified
Impact Resistance Against Shot-Bag Qualified
Radiation Resistance Qualified
Ball Impact Peeling Resistance Qualified
Polyvinyl Butyral PVB Interlayer Film for Laminated Glass
Polyvinyl Butyral PVB interlayer film have the impact resistance. The
single  flat glass would lead to serious injuries to human being or
other properties when it’s broken, but Laminated glass with Polyvinyl
Butyral PVB interlayer film can stick the glass together when it’s
impacted, which can remain it’s safety. The safety of the laminated
glass with Polyvinyl Butyral PVB interlayer film is popularly
recognized as safety glass in architectural design.
And Polyvinyl Butyral PVB is good at penetration resistance, so is
better than tempered glass in Automotive windshield implication.
CNC-INTERLAYER TECH:
【1】CNC-Force® EVA INERLAYER FOR ARCHITECTURAL LAMINATED GLASS
【2】CNC-Smart® SMART FILM FOR PRIVACY SWITCHABLE GLASS
【3】CNC-Shield® PVB INTERLAYER FOR AUTOMOTIVE WINDSHIELD GLASS
Mail: cnc@cncnext.com Web: www.CNCnext.com
benext77@gmail.com/benext77@hotmail.com

Vacuuming And Heating Instruction of Polyvinyl Butyral PVB Interlayer Film
www.helloglass.com

Preheating and Exhaust of PVB Film:
After the glass and Polyvinyl Butyral PVB interlayer film is combined,
there are some air between the PVB interlayer film and the glasses.
PVB Interlayer Film can dissolve some of air by itself, but not very
much of it. To extrude the air out, here are the methods:
+Hot roller extrude exhausting air
Hot roller exhausting air has many ways: single thermostat chamber
with double rollers or double thermostat chambers with double rollers.
Single thermostat chamber with double rollers: usually for laminating
flat glass with Polyvinyl Butyral PVB interlayer film. When
pre-laminated glass goes through the frist roller, most of air will be
squeezed  out. Then the pre-laminated glass goes into the thermostat
chamber to heat, then, go through second roller to extrude exhaust
after heating. At this most, air isolation and edge seal is finished
at the same time, the pre-laminated glass looks prey translucent while
the narrow area around edge shows transparent.
The temperature control is very important, in order to expulsion of
air and seal sides of pre-laminated glass successfully, temperature
should be kept about 70-80 degree after going through the second
roller.
If you doesn’t find the prey translucent area after the second
rolling, which means the glass temperature is too low. On the
contrary, if the temperature is too high, edges of the pre-laminated
glass will be sealed too early, which will stop squeeze air out, then
bubbles will appears in the laminated glass.
Vacuuming exhausting air
This method is specially for laminating uneven glass with PVB
interlayer film, such as automobile windshield glass, bending glass.
Put the pre-laminated glass into a vacuum bag or put vacuum rubber
ring to seal the glass, then start  the vacuum pump.
The procedure is divided into two steps: cold vacuuming period and hot
vacuuming period. In the cold vacuuming period, the temperature is
about 25 degrees and holding time about 15 minutes, and the negative
pressure should be at least 0.8 bar. In the hot vacuuming period,
temperature is about 80-110degrees, and holding time about 30 minutes.
And the most suitable temperature and time of hot vacuuming exhausting
air depends on the machine and producing speed.The transparency of the
laminated glass is better if it’s made of the hot vacuuming exhausting
air method.
High-pressure Molding of PVB Interlayer Film
The Pre-laminated glass have went through the Preheating and
Exhausting Air procedure, but the whole pre-laminated glass still have
air inside the laminated glass. In order to finally melt the PVB
Interlayer film and exhausting all the air out, the pre-laminated
glass should be put into the higher pressure laminating autoclave.
There are three steps:
+Heating
Put the pre-laminated glass vertically on the bracket, make sure the
space between the two pre-laminated glass is equal, so each
pre-laminated glass will get the same pressure. Make sure the
pre-laminated glass not touch the metal part of the machine, to
prevent the part of pre-laminated glass get too high temperature and
break out. Close the autoclave and start heating. After the
temperature rise up to 50 degree. Increase the pressure inside the
autoclave. It’s suggested that the speed of increasing pressure and
temperature is :0.06MPA/MIN and 5 degree/min. If the temperature and
pressure is not synchronous, please adust the machine. If temperature
is too fast, then stop increasing the temperature until the pressure
catch up, vice verse .
+Maintaining Pressure Stage:
The temperature and pressure are very important parameters for making
laminated glass successfully. When the temperature and pressure reach
to the setted point (like 120-140 degrees), pay attention to these two
parameters carefully. If the temperature is lower than  130 degree,
the pressure time should be  longer.But if the temperature is lower
than 120 degree, it’s not helpful to keep the pressure time longer.
And the laminated glass may be not adhesive or not very strong. If the
pressure is less than 1.2-1.4MPA, the time for pressure should be
longer, but at the same time, the temperature should be 120-140
degrees. If the temperature is higher than 160 degree, the PVB
interlayer film will turn yellow. And the laminated glass is failure.
+ Cooling with pressure stage
After the maintaining pressure stage, it’s time to cooling the
laminated glass. Still maintain the pressure and open the cooling
water to reduce the temperature. When the temperature reaches 45
degree, start to reduce the pressure. When open the autoclave door,
check the temperature of the laminated glass up and down, make sure
the temperature of the laminated glass is even. Don’t reduce the
pressure too early, otherwise the bubbles would appear on the edges of
the laminated glass.

CNC-INTERLAYER TECH:
【1】CNC-Force® EVA INERLAYER FOR ARCHITECTURAL LAMINATED GLASS
【2】CNC-Smart® SMART FILM FOR PRIVACY SWITCHABLE GLASS
【3】CNC-Shield® PVB INTERLAYER FOR AUTOMOTIVE WINDSHIELD GLASS
Mail: cnc@cncnext.com
Web: www.CNCnext.com
benext77@gmail.com/
benext77@hotmail.com

Delamination Analysis of Laminated Glass with Polyvinyl Butyral PVB
Interlayer Film
By www.helloglass.com

Condition One: Delamination Appears in Lines.
Reason:
When combining the glass with the Polyvinyl Butyral PVB interlayer
film, some folds occur , or some place of Polyvinyl Butyral PVB
interlayer film is too thin due to the hard pulling of the Polyvinyl
Butyral PVB interlayer film. Especially the place near the hole or
edges,  some Polyvinyl Butyral PVB interlayer film have been shrink,
so the Polyvinyl Butyral PVB interlayer film is too thin or even gone
between the too glasses.

Solution:
When combining the glass with Polyvinyl Butyral PVB interlayer film,
pull the Polyvinyl Butyral PVB interlayer film gently, make sure no
fold of Polyvinyl Butyral PVB interlayer film, and the Polyvinyl
Butyral PVB interlayer film is 2mm wider than the glass. And also cut
the Polyvinyl Butyral PVB interlayer film gently.

Condition Two: Delamination in Edges and Holes of Laminated Glass with
Polyvinyl Butyral PVB Interlayer Film
Reason:
The plainness of the edges and holes of the tempered glass is not good.

Solution:
Adjust the plainness of the tempered glass, clip the edges of the
pre-laminated glass before putted into the autoclave. But don’t use
too big clips, in case the PVB Film’s shape changes.

Condition Three: Delamination on Edges and Holes After the Laminated
Glass is Installed in the Building

Solution: Install the laminated glass gently. it’s better if use the
wrench with scale to hole the laminated glass. Make sure the glass
glue is suitable for the laminated glass, and it should be neutral
glue.

Condition Four: Irregular Delamination of Laminated Glass with
Polyvinyl Butyral PVB Interlayer Film
Reason1:
The Adhesion of Polyvinyl Butyral PVB interlayer film and glass is not strong.
Solution1:
The washing glass water is not good quality, it’s better use the water
whose electric conductivity is lower than 20us.

Solution2:
The Polyvinyl Butyral PVB interlayer film absorbed too much moisture,
maybe more than 6%. If moisture of Polyvinyl Butyral PVB interlayer
film is higher than 1%, the laminated glass may appear white haze.

Solution3:
The combination of pre-laminated glass and roller exhausting air stage
maybe not operate correctly, which lead to Polyvinyl Butyral PVB
interlayer film not reacted perfectly. The main parameters are
temperature, pressure and time.

Solution4：
The glass surface is not clean and dry enough.

Reason2:
The Polyvinyl Butyral PVB interlayer film is too thin.
Solution:
Use thicker or more layer of Polyvinyl Butyral PVB interlayer film.

Reason3:
The plainness of the tempered glass is not good.
Solution: Choose better quality tempered glass.

Condition Five: Delamination of Laminated Glass with Polyvinyl Butyral
PVB Interlayer Film When in Boling Water Test

Reason1:
Two much air contained inside the laminated glass with Polyvinyl
Butyral PVB interlayer film.
Solution1:
Sealing the edges too early in the pre-pressure exhausting air stage,
which lead to the air stocked inside the laminated glass. Although, it
seams successful when the laminated glass come out from the autoclave,
but when in the boiling test, the bubbles will appears.
Reason2:
The Polyvinyl Butyral PVB interlayer film has absorbed too much
moisture before laminating.
Solution2:
Adjust the storage conditions, make sure the moisture of Polyvinyl
Butyral PVB interlayer film is less than 0.55%.

Copyright:

All rights reserved by CNC-INTERLAYER TECH:
【1】CNC-Force® EVA INERLAYER FOR ARCHITECTURAL LAMINATED GLASS
【2】CNC-Smart® SMART FILM FOR PRIVACY SWITCHABLE GLASS
【3】CNC-Shield® PVB INTERLAYER FOR AUTOMOTIVE WINDSHIELD GLASS
Mail: cnc@cncnext.com
Web: www.CNCnext.com
benext77@gmail.com/
benext77@hotmail.com