How to Process Laminated Glass with EVA Film Interlayer

How to Process Laminated Glass with EVA Film Interlayer

How Do You Process Laminated Glass with EVA Film?

1)Processing the Laminated Glass with EVA Film is different from the laminating with PVB Film.

Different in Oven: Laminating with PVB Film you need autoclave; laminating with EVA Film you need a simple oven: one-step laminating oven which is simpler and easier to process, and less cost to install.

2)Install the ONE-Step of vacuum laminating Oven

Make sure the silicone vacuuming bag is great, and the heating is even inside the oven.

3)Combine the pre-laminated glass

Normal the combination is :GLASS+EVA FILM+GLASS

Cut the extra EVA Film gently.

Solid the pre-laminated glass with high-temperature tape

4) Put the pre-laminated glass inside silicone vacuum bag

Seal the silicone vacuum bag.

Start vacuum pump, double check the vacuuming is working well, and the value of vacuum pump reaches the requirement.

5)Heating in two temperature stages

Normally, the heating will be set in two stage:

Low temperature stage: 60 degrees C for 15 minutes

High temperature stage:130 degrees C for 40 minutes

6)Do NOT stop vacuuming after the laminated glass is cool as room temperature

Don’t stop vacuuming until the laminated glass is cool to the room temperature, Or the bubbles will come out inside the laminated glass.

Preparation for Glass Lamination with EVA Film

Preparation for Lamination:

1)Cut the glass as the size you want, and use Glass Edging Machines to shape the edges of the glasses, which will avoid the glasses hurt the silicon vacuum bag.

2)Use the purified water, deionized water, industrial alcohol or Ethanol to clean the glasses, then use the clean hot wind to dry the glasses. Make sure no black spot, water mark, finger print etc on the glasses.

Pre-Laminating:

1)Put the EVA FILM on the bottom glass, make sure the EVA Film is plain, then put the other glass on the EVA Film, then use the high-temperature-resistance tape to solid the pre-laminated glass.

2)Cut the extra EVA FILM that outside the pre-laminated glass. Don’t pull the EVA Film hard to avoid the remove of the EVA Film. Cutting out the extra EVA Film can void the extra EVA Film melting and sealing the edges of the laminating glass and hold back vacuuming.

3)When you put the pre-laminated glass in the silicon bag, make sure that each pre-laminated glass is 3-5cm away from each other to help vacuuming.

4)To help vacuuming, you can also put the wooden bar around the silicon bag to help vacuuming.

Notes: if you seal the pre-laminated glass totally with tape, you need to make some small holes on the tapes to help vacuuming.

Heating Procedures of Laminating Glass with EVA Film

1)Before the silicon bag shelf being pushed into the oven, start the vacuum pump to vacuuming for 3-5five mins. Check whether the silicon bag is leaking or not. And the vacuum value should at least be 0.095Mpa.

2)Push the silicon bag shelf into the oven, then set the parameters of temperature and time. Following two STAGE heating temperature and time. The low temperature stage is 60degress C and 15mins. And the high temperature stage is 130 degree C and 40 mins (notes:following the instructions that the EVA FILM MANUFACTURERS give to you, the parameters maybe different for different manufacturers). Because it takes time for the heat transfer through the silicon bag, so the temperature the detector gets may be different from the real temperature of the laminated glass.

3)Stop heating. Wait till the temperature is lower than 75 degrees, then open the oven door and pull out the silicon shelf to help cooling. But don’t open the silicon bag or let cold water touch the laminated glass.

4)After the temperature is lower than 45 degree, now you can open the silicon bag and check the laminated glass.

Processing Temperature and Time for Laminating Glass with EVA FILM

First I would to say that no fixed standard value for the processing parameters, because different EVA film manufacturer have different formula for the EVA FILM, and different glass laminating machine manufacturer have different property for the machine.What’s more, the weather and moisture is different in different regions, which also would affect the processing parameters. So there is no fixed standard value for the processing temperature and time for laminating glass with EVA FILM.

But I can tell you some general rules of the processing parameters for laminating glass with EVA FILM.

1) Indoor EVA FILM (like 110 degrees C) need lower temperature for laminating than outdoor EVA FILM (130 degrees C).

2) If you laminating thicker glass with more layers of EVA FILM, then the keeping time should be longer, for example if 5mmglass+0.38mm EVA FILM +5mm glass is 130 degree and 40 min, then 10mm glass+2layer EVA FILM +10mm glass should be 130 degree and 55mins.

Because more time is needed for the heat pass through the thicker glass and more layer of EVA FILM.

3) The tempered glass laminating with EVA FILM needs longer keeping time than the flat glass laminating with EVA FILM.

4) If the weather is colder in your region, then the keeping time should be longer.

And it’s also different for different glass laminating machine, because the heating part is different.

So :

1) If you change the EVA FILM supplier, maybe you have to adjusting the processing parameters for laminating glass with EVA FILM.

2) If you buy a new EVA glass laminating machine, and the processing parameters maybe different from your older one.

3) If the weather changes from different seasons, maybe you also need to adjust the processing parameters for laminating glass with EVA FILM.

4) Yes, every EVA FILM Manufacturers would offer you the processing instructions or parameters for laminating glass with EVA FILM, but you don’t have to follow them exactly. You should change some according to your real situation.

Why Two Periods of Temperature for Laminating Glass with EVA FILM?

1)Low temperature period can help vacuuming, at this temperature the EVA Film is still not melted, but the temperature is higher than room temperature, the numerators of air would move faster, which is helpful for the vacuuming. If vacuuming is not good, the bubbles would come out the laminated glass.

2)If the moisture in your place is high, and maybe the EVA FILM has already absorbed some moisture, the low temperature period would help dry the EVA FILM before the EVA FILM start to melt, which can avoid bubbles and be good for the adhesion of the EVA FILM.

3)If you wash the glass, and maybe the glasses are not dry enough, the low temperature period can help dry the glasses.

For laminating with papers, if you print ink in the papers are not dry enough, the low temperature period can help dry the print ink.

4)And also, after the low temperature period, the machine is stay hot too, so temperature detector can measure a more correct temperature closer to real temperature of the laminated glass.

Notes of Making Laminated Glass with EVA Interlayer Film

1).Glass is not a good conductor of heat, so please don’t laminate different thickness of glasses at the same silicon bag. It’s more easily for the thin laminated glass with EVA Interlayer Film to transfer heat, so the keeping heating time at high temperature can be shorter. And if the laminated glass is thicker, the keeping heating time for the high temperature should be longer.

2).For the different thickness of the fabric or papers, the thickness of EVA interlayer film should be different. For the thin and small silk, the 0.25 thickness EVA interlayer film would be ok. For the thicker and bigger silk or fabric, the thickness of EVA Interlayer Film should be 0.38mm or more.

3).Normally, the EVA Interlayer Film is soften at 75 degree C and start to react at about 100 degree C. And the EVA Interlayer Film would be totally melted at about 115 degree C. Generally speaking, when the detector gets the temperature of 120degree C, the real temperature of EVA Interlayer Film gets 115 degree C.

4).The mobility of different thickness of EVA Interlayer Films is different when being heated. The mobility of thicker EVA Interlayer Film is more than the thinner EVA Interlayer Film. So please adjust the time of high-temperature-period of different thickness EVA Interlayer Film. If the high-temperature-period is too long, the melted EVA Film Interlayer would leak from the laminated glass, which will cause bubbles in the edges of laminated glass.

5).The quality of laminated glass is partly decided by the plainness of the glasses. So please try to select the good plainness of flat glass. If you are laminating with tempered glass, please use the thicker EVA Film Interlayer. For the poor plainness glass, the laminated glass may be broken when vacuuming or cause bubbles of laminated glass.

CNC Glass Interlayer Tech
cnc@cncglass.com

Knowledge of Switchable Privacy Glass Solution

Knowledge of Switchable Privacy Glass Solution

Description ofSmart Glass (Switchable Glass, Privacy Glass, Magic Glass)

Privacy glass is laminated with special polymer film, which allows people to control the transparency of the final laminated glass. The smart choice can be controlled by electronic, sound, sunlight etc. Generally, the smart glass (privacy glass) is translucent when the smart choice is off and transparent when the smart choice is on. The smart glass can provide privacy, light control etc. for people. Smart glass technologies include electro chromic devices, suspended particle devices, Micro-Blinds and liquid crystal devices. And here we are going to talk about the privacy glass with Polymer dispersed liquid crystal devices.

The privacy glass is well implied in high class architectures, bank, office room, super-market, showcase, auto-car, hotel windows, jewelry store, etc.

When implying privacy glass, you need consider the cost of installation, the electricity power, durability, and the kind of functional features you care most, like the speed of switching, degrees of transparency when the smart choice is on, the size of the privacy glass etc.

The characteristics of Switchable film (PDLC FILM, Magic film, Smart film, Privacy Film)

+ The translucent state of switchable film

The switchable film is composed by two transparent conductive film laminating with a polymer liquid core. And the polymer liquid core composes crystal ball and polymer. When the light pass through the PDLC FILM and reach the liquid crystal ball and polymer, the light is scattering. And the switchable film appears translucent.

+ The transparent state of switchable film

When electricity power is connected, the polymer-liquid crystal core is allowing light pass through, the switchable film appear transparent.

+ Haze of switchable film

To identify the switchable film quality, haze (the opposite is transparence ) is the key parameter to describe the switchable film. When the power is on, the switchable film should be as transparent as possible , when the power is off, the switchable film should be more haze.

+ View range of the switchable film

If the scattering is more, the view range is wide, the switchable film appears more haze.

Two Kinds of Switchable Privacy Film

+ Non-Adhesive Privacy Film ——have to be processed in laminating way, but very good in safety.

+Self-Adhesive Privacy Film——Very convenient and flexible in installation of the already built windows.

The implication of Smart Glass(Switchable Glass, Privacy Glass, Magic Glass )

+ Imply Smart glass in door, windows or the glass insulation. For example, in the windows of the business office, when the smart glass is on, the state of the switchable glass is transparent, you will feel the room space is big, and feel comfortable. When you are in the business meeting, you need some privacy, you can just turn off the switchable privacy glass, the privacy glass turns to be translucent, you have the privacy.

+ Using the smart glass for projecting screen. In the state of translucent, the privacy glass can strengthen the view effect of the projection. The viewable range can be 140 degrees.

+ Imply the smart glass in bank industry, jewelry industry and showcase. When it’s off work, you can turn off the privacy glass, the sate of smart glass turns into translucent. Which can protect the high-value properties from the criminals. Also the smart glass is laminated with advanced EVA INTERLAYER FILM, when the glass is broken,the EVA INTERLAYER FILM will stick the broken glass pieces, avoiding the broken glass hurting people or properties.

+Imply the smart glass in hospital. The smart glass can be used to replace curtains, which is safe and solid and can be view insulation.

+ Imply the smart glass in high-end hotel, cooperation building, bathroom. Which shows the humane optional and high classic artistic sense.

CNC Glass Interlayer Tech
cnc@cncglass.com

Analyse Bubbles of Laminated Glass with EVA Film Interlayer

Analyse Bubbles of Laminated Glass with EVA Film Interlayer

What People May Think, When They Face Bubbles

When some customers processing laminated glass with EVA FILM, bubbles appear inside the laminated glass, People would always think is this way:

1.The EVA Film I ordered last time, didn’t have bubbles problem, why this time the bubbles is coming out, that’s definitely the reason of the quality of EVA Film.

2. Some customers face this situation. Maybe they don’t use EVA Film very much, so they don’t finish the one roll of EVA FILM in a short period. They used two thirds of the roll of EVA film, and after several weeks, they go back to use the left part of the roll. But this time the bubbles coming out, they are very confused. How come the same roll has different quality?

3. Some customer may just change the new EVA FILM supplier and the bubbles comes out. Even their new supplyer tell them it’s all about the processing , they would not believe him, they would think it’s of course the problem of the quality of your EVA film, because my older supplier don’t have this bubbles problem.

General Reasons for Bubbles

Many Laminated glass producer have misconception of the reasons of the bubbles problems. Here is the real why:

1. First situation: the temperature is too high, maybe more than 180 degree, which will cause the compound to break down and create gas. In this way, it’s just reducing your temperature, and everything would just be fine.

2. Second situation: the temperature in the oven is not average, which means some part of the glass, is hotter than others. So some part of the EVA film will melt and finish the crosslink reaction while other parts of EVA Film is still not melted, which will interrupt the vacuuming and cause the bubbles. For this situation, we suggest you modified the lamination machine.

3. Third situation: the Vacuum machine is old or the vacuum ability is not good enough. If the vacuum machine is old, renew it. If the vacuum ability is not powerful enough, try to buy a new one.

4. Four situation: the air moisture is high. The moisture in the air in your region is changed, which will easily cause the EVA film wet when it exposes in the air. Moisture in the EVA FILM would cause the bubbles. Although the EVA FILM is less sensitive to moisture compared with PVB FILM. But if the moisture is too high, the bubbles will also come out.

Some customer open the packaged of one roll, and don’t use it up at one time. And the left part of the EVA film will absorb the moisture in the air and cause the bubbles.

5. Five Situation: Different EVA FILM supplier has different formula for EVA FILM, so if you change the EVA FILM supplier, you need to adjusting the processing parameters according to the supplier’s EVA FILM property.

Micro Reasons for Bubbles:

I wrote an article Bubbles Solution for Laminated Class with EVA Film, talked about the situations that bubbles come out the laminated glass. It is macro views. Today I like to talk about the other reasons in micro views that cause the bubbles in laminating glass with EVA Film.

1. The plainness of the tempered glass is bad.

+As you known, tempered glass is less plain than the flat glass. So you should choose a company that produce better tempered glass.

+ Since the tempered glass’s plainness is worse than flat glass, you should use thicker EVA FILM interlayer for the tempered glass. Generally speaking, the tempered glass should be laminated with at least 0.8 mm thickness EVA Film Interlayer.

+ Laminate Less layers “pre- laminated glass” in a silicon bag at one time. If you laminate too many layers “pre-laminated glass” in a silicon bag at one time, the vacuuming would not work perfect and cause the bubbles.

+If you laminated small pieces “pre-laminated glasses” at the same time, put the “pre –laminated glasses” on the fabric, which will help vacuum, and the fabric should cover the vacuum hole to make sure the vacuum hole is not sealed by the silicone bag itself.

2. Check if the silicon bag is leaking.

1) Averagely speaking, a silicon bag can be used for several years. But check the silicon bag if your laminated glasses have bubbles.

2) Check the concavo convex of the edge of the silicon bag is sealed perfectly when processing laminated glass with EVA Film.

3. It’s too early to put the laminating glass out of the oven,

The temperature of laminated glass is still very high and the EVA FILM is still melting and reacting. When the laminated glass is getting cold, the melted EVA FILM is contracting, and the EVA Film can’t fully fill the gap between two glasses, so bubbles come out.

4.It’s too early to stop the vacuuming.

And the cross link reaction of the EVA film is not totally finished and stable. And also the silicon bag would suck same air back in to the bag, which cause the bubbles. So generally speaking, don’t stop vacuuming until the temperature of the laminated glass is lower than 45 degrees.

Notes:Always remember you put the wire net on the vacuuming hole to make sure the vacuuming is not stop by the laminated glass on the hole. To be more perfect, also can use wire net over the laminated glass.

Case Study: Bubbles of Laminated Glass with EVA Film Interlayer

We have seen a situation in this way: Bubbles comes out in the Laminated Glass. And we checks all the details of vacuuming and vacuuming is definitely no problem.

But the bubbles still comes out in the laminated glass. And the bubbles are regular and on lines.

Finally we realized that the bubble lines are right upon the heating pipes.

So we reduced the temperatures and did the test. Then no bubbles comes out, but some part of laminated glass is not very transparent.

So we know the reason:

Because the heating pipes are under silicon bag, when laminating glass, the part of laminated glass right upon the heating pipes are in higher temperature. And the temperature inside the oven is not in average.

Remember that when the temperature is too high, the copolymer will be breaking up and produce gas which would cause bubbles inside laminated glass.

So It’s better of you can talk to the EVA Glass Lamination Oven producer to modify the oven.

CNC Glass Interlayer Tech
cnc@cncglass.com