PRINTED AND UNPRINTED COMPOSITE LAMINATED GLASS AND PRODUCTION

METHOD

This invention is related to the printed and unprinted composite laminated glass production method that can be used in industrial, architectural areas such as furniture, refrigerator, dishwasher, fixed kitchen furniture, air conditioner, automotive, decoration, windows and doors, one surface of which is glass and the other surface is metal, plastic, fabric, wood, paper, mining products (marble etc. sand etc, and colored stone etc.)

Laminated glass already known is the unprinted laminated glass used in automotive and architectural areas. It is produced by placing thermo polymers such as PVB (polyvinyl butyral) or EVA (ethylene vinyl acetate), which have adhesive characteristics between at least two glasses (Glass+PVB or EVA+Glass)

In the production through use of PVB, PVB is placed between glasses and pipe- type roving, one side of which is slotted, is fitted on the edges of the glass. After the air between the glasses is vacuumed at 30 minutes/square meter from the tip of such roving and then it is carried into an autoclave tank resistant to high temperature and pressure. Inside the tank glasses are placed on special printing apparatus and the lid of the tank is locked. The tank is filled with pressure at 13 bars through the edge roving. After 45 minutes, the environment under pressure is started to be heated. It is kept at 35-165 C° for 120 minutes. At the end of his period, pressured air is discharged and environment is cooled down for 15 minutes until it comes to room temperature and glasses are taken out of the tank to complete the production.

This production process lasts for about 3 hours and high level of energy is consumed for the pressure, heating and cooling procedures. In order to increase resistance against pressure, autoclave tank is of cylindrical shape. And this restricts the amount of glass put inside and there are places unused inside the autoclave. As the amount of work carried out by high pressure and heating energy inside the tank is low, more energy is used. And as high pressure, heating and cooling is performed in the same environment, energy consumption and therefore production time increase. Furthermore, investment costs for a tank resistant to high pressure and having holes due to cables and hose pipes is rather high. Special equipment and trained personnel needed for maintenance and tests also increase such cost.

In this production method, since the air remained between the sheets of the glass is vacuumed through the edge roving, glasses in different sizes and holes cannot be produced.

There are two types of unprinted laminated glass production using EVA. Larger glass can be produced with EVA in PVB production method as stated above. All processes and production results are the same. Other production method using EVA is for smaller sizes of glass. This production is carried out inside lamination furnaces and eva polymer is placed between two sheets of glasses at least and then put inside the drawer of the furnace. Inside the drawer, there are vacuum channels and glass placement areas. The glass placed in that area is coated with a silicone plate specially manufactured which is locked for air tightness. The air inside is vacuumed at 30 minutes/square meter and the drawer is left inside the furnace and heated. After it is kept at 135-165 C° for 120 minutes is taken out for cooling down. After 45 minutes, when the products reach room temperature, silicon plate is removed and the production is completed.

The dimensions of the glasses between which eva polymer is placed cannot be different from each other. If the entire place inside the drawer is not used, there may be loss of energy therefore cost increases. In the event that there is leakage from the locks of the silicone plate used for air tightness, all glass products will be defective. Therefore, the rate of loss products is high. Special apparatus are made for the glasses smaller or larger than the placement area inside the drawer. When variety of products is taken into consideration, the cost is relatively high due to such apparatus.

As the heating system of the furnace is located on the side walls of the furnace, the sides of drawer and middle sections are not heated at the same time. This results in defective products. Another reason that increases energy consumption is that production lasts for 150 minutes because of the time needed to cool down the drawer. Therefore it is not suitable for mass production due to high investment costs.

The wires on the heaters used in all production processes defined above are not insulated. Since they corrode; repair and maintenance costs are high. And due to the structure of such heaters, efficiency gets lower and energy consumption increases. Whatever the dimensions of glass are, energy loss is high because inner volume is heated.

Laminated glass with patterns already known is produced through the methods specified above. To make patterns, a plate carrying the pattern is inserted between two sheets of glass. However, in this production, the amount of PVB and EVA used is twice more. Glass +PVB or EVA +pattern carrier + PVB or EVA + Glass. As pattern carrier, cloth, paper and plastic films are used. On the back side of the pattern and second polymer layer increase the cost. Cost of defective products is high. Energy consumption is higher. Furthermore, glass both increase the weight of the products and makes it harder to attach it on the wall or wooden surfaces etc, and the cost. The dimensions of the pattern carrier cannot be smaller than those of glass. Therefore, sectional pattern production is not possible.

Another known method of patterned laminated glass is carried out by digital printing on the surface of glass. In his kind of production, PVB or EVA polymers are inserted between the sheets of glass. As a pattern carrier, one of the surfaces of the glass is used. On the surface of the glass, pattern is drawn through digital printing. Later on, the back of the pattern is covered with ground paint. Then the polymer and second sheet of glass is placed. By using above methods, the glass is laminated.

As one of patterned side of the glass is coated with ground paint in his method of production, adhesive polymer is attached through ground paint not through the glass. And his causes laminated glass feature on that section. In terms of usage, laminated glasses should be safety glass, the glasses produced in his method is not included in the class of safety glass. And this reduces the area of use of the product. Besides, as the surface energy of the glass is low (other materials hold onto glass surface), printing resolution will be of low quality. Because of the same reason, costs of printing and printing machine will be much higher. It is non-durable against sun light as the ink cannot hold onto the glass. It is non persistent especially in outdoor areas and interiors having direct sunlight. As it is digital printing, it does not have the appearance of paper, cloth, plastic pattern carriers. Patterns must be dried for ground covering behind the pattern during digital printing. This process is carried out in special rooms insulated from dust and smoke and therefore costs of investment and production will be high.

Another known method of printed laminated glass is the method of production with liquid polymer, which is not commonly used today, or liquid adhesive. This production is carried out with one or two sheets of glass and the cost of production is high and not suitable for mass production. One surface of the glass is applied adhesive and then pattern carrier is placed and pressed. In his method, liquid absorbent pattern carriers such as paper and cloth cannot be used. Instead, pattern carriers such as plastic or marble are used.

In this production method, only plain glass is used. As it is pressed, production in larger dimensions is not possible. The pattern carrier must not be affected by liquid adhesive. Its adherence to the glass is lower than that of PVB and EVA. Air bubble voids may occur between the glass and pattern carrier. As it is affected by heat, humidity and sun, its area of use is relatively restricted. It is not suitable for mass production. Labor costs and production process is long. The cost of investment is high due to molding and pressing procedures.

In his method, unprinted laminated glass is produced by placing PVB or EVA polymers on one side of the glass and vacuuming it at 85-145 ⁰ C for 15 minutes. The production is performed with the help of a machine having drawers on four sides and vacuumed glass tube heaters inside the drawers covered with flexible film. Unprinted laminated glass is produced by applying transparent film on thermo polymer. The reason to apply transparent film is to provide passage between the surfaces. The advantages of our invention of printed and unprinted composite laminated glass comparing to previous methods are as the following;

^* Production can be done at lower temperatures compared to already known production method using PVB or EVA polymers already used,

*With this method, laminated glass can be produced with one single sheet of glass while at least two sheets of glass are required in production method using PVB and EVA, *lt does not required pressing a special molding as in method using liquid adhesive, which is the only known method of single sheet of glass,

*lt is cost effective since the pattern is applied on a single sheet of glass and the weight of product is relatively lower.

*Production of glass in variety of dimensions can be made by the same machine with the same method.

*Energy consumption and cost of investment is low,

*lt is suitable for mass production due to the production method and as the production process is short,

* Pattern carrier in different size from the glass is applied on the back of the sheet of glass,

*Different pattern carriers are applied on the same sheet of glass in different sizes in the same production process,

*Certain sections of the same glass are covered with pattern carrier and molded,

*lt is in compliance with safety glass standards as printed glass does not affect the adherence of PVB or EVA,

* Metal, plastic, fabric, wood, paper, mining products (marble etc. sand etc, and colored stone etc.) are used as pattern carriers,

*As the patterns are on the carrier they are not affected by humidity, light and heat,

^* Phosphorescent printed and unprinted laminated glass which is by the only application known so far can be produced,

*Products which are completed heating process are cooled down outside the machinery; energy consumption is low as heat loss inside the machine is prevented.

*As the heaters are located on upper and lower base of the machine, the area where the glass is placed inside the drawer is heated. By this way loss of energy is minimized, ^* As the heaters are inside the glass tubes, they do not corrode, their economic life is long and energy consumption does not change,

^* As the heaters do not radiate, they do not disseminate radiation and therefore do not cause any deterioration of the product,

*The film used for vacuuming only vacuums the area in the area where the product is placed; the products in the same drawer are independent from each other. Therefore, products defects resulting from leakage remains in that area only and the loss of product is minimized,

*lt is not possible to recycle the product with already known methods; however, with this method it is possible. Thanks to this invention, the products is placed inside the same machinery again and heated and the pattern on back of the glass is detached and new pattern is placed on the adhesive polymer remaining on the surface of the glass and production begins.

*Glasses having patterns formed by carving which cannot be laminated through any other method can be laminated.

The flow chart of the invention of printed and unprinted composite laminated glass production method subject to our application is given in Table-1.

In this invention, the production is made with w machinery having drawers on four sides. At the lower section of the drawers, there is a wire board like a grid, and teflon or silicone plate and again grid-like wire board. The parts of wire boards' upper side must be coated with plastic to prevent scratches. This wire board helps air be vacuumed. Besides, it eliminates the requirement to use molding or auxiliary materials. There is a flexible film to increase vacuum impermeability. This film made from Teflon, silicone, pvc, paper, plastic, metal etc of impermeable characteristic. There is a vacuum pipe connection In order to vacuum the air inside the drawers and provide impermeability.

In the machinery, there are tubes in which heating wires on the upper and lower sides and they are placed after the air inside is vacuumed. These tubes are connected in a way that they are independent from each other. All parts of the machinery are also coated with heat insulated material. To measure temperature, semi-conducting electronic sensors are used.

In this invention, printed and unprinted composite laminated glass is placed on wire board coated with plastics over the drawer made of tempered or non-tempered glass (Figure-1-A/1). PVB or EVA polymer cut in the sizes of pattern carrier (Figure-1- A/2) is then placed on the pattern carrier glass (Figure-1-A/3).lf the pattern is bigger than pattern carrier, it is cut as much as the size of thermo polymer glass. Later, the surface is covered with a flexible film of impermeable characteristics (Figure-1-C/1) and the air is vacuumed (§ekil-1-C/2). After it is vacuumed for 3 minutes independently from the sizes of glass, it is taken inside the heating area in the machine. Depending on the structure of the pattern carrier, it is kept at 85-145 C for 8-10 minutes (Figure-1-C/3).ln the meantime; product is put inside the other drawer and vacuumed. While the first drawer is taken out and cooled down (Figure-1-C/4), other drawer is put inside the heating area. And this process continues successively for each of the drawers.

For pattern carriers such as marble, printed sheet iron, wood which has pores that PVB or EVA polymers cannot cover, PVB or EVA thermo polymers are used. Before such type of pattern carriers are placed inside the drawer, the surfaces of which carriers are coated with liquid thermo polymer through spraying (Figure-1-B/1).The surface is than scraped with a clean cut material and excess liquid thermo polymer is removed (Figure-1-B/2) and then placed inside the drawer (Figure-1-B/3) and above mentioned vacuuming and heating processes begin.

Before the printed glasses, the surfaces of which is carved through acid or mechanically are laminated, the spaces in the pattern is filled with materials such as phosphor powder, colored sand, silver, and photo chromic and thermo chromic particles. Then PVB or EVA polymer is placed on. The ground paint is inserted and pattern carrier is placed and production process begins. The production can also be made by applying the paint which can fill in such pores onto the pattern carrier. To do this, transparent paint is applied onto the pattern carrier and then such particles are poured. The particles adhere to the transparent paint form the pattern and the glass is laminated.