LU80723A1 - PROCESS FOR THE MANUFACTURE OF LAMINATED PANELS - Google Patents

Description

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~ f 7 O * ^ RAND-DUCHY OF LUXEMBOURG

Patent No .................... / ...... £ J

from ... 27 ..... December ...... 1.9.7 £ Sir

Title issued from the National Economy and the Middle Classes Industrial Property Service

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MflùM '~ -4 --- Application for iUJo Invention Patent. .................................................. ............

I. Request

Mr. Guido Vçrhaeghe. Leuvensestraat 75. B-3054 _____________________________________________ (1) „I.Qo.n.beek..B..e..l..g.1..que .. * ..... represented ..... by. .... Mr. Charles München, .............

* patent attorney ..... â ..... Luxembourg, ..... acting on the quay i ... from .............. .............. (2) agent ................................ .................................................. .................................................. .................................................. .................................................. ..

deposits this twenty-seven December 1900 seventy-eight {3) at ....... 15 ... 00 .. hours, at the Ministry of National Economy and the Middle Classes, in Luxembourg: 1. la this request for obtaining a patent for an invention concerning: .... “. Process for the manufacture of panels ..... l.ajn.in § s _________________________________________________“) declares, in assuming responsibility for this declaration, that the inventor (s) is (are): ............................ .................................................. ......................... the ..... depositor .................. .................................................. .................................................. .................

2. the delegation of power, dated ... LQ..Qnb6 .. £ .k ............................ ..... the 3. description in language f, Γ.δ.n.ç.a iitS_Θ .......................... ......... of the invention in two copies; 4 ............ 5 ................. drawing boards, in two copies; 5. the receipt of the fees paid to the Luxembourg Registration Office on .......... 27 ...... December ..... 1978 ......... .................................................. .................................................. .................................................. ..................................

claims for the above patent application the priority of one (s) request (s) from ........................... . /. / .......................................... .... ................ filed in (7) .............. ............ ......................... U ........................ .................................................. ..

the .........................................././.... .................................................. .................................................. .................................................. .................................................. ................. (8) .............................. ...................................... U ........... .................................................. .................................................. .................................................. ..................................................

on behalf of ............... ................................ ........He......................................... .................................................. .................. ................................ ............................................. (9) elect domicile for him / her and, if appointed, for his / her representative, in Luxembourg .................................. ......

...... lia., ..... bou.ley.ard ...... Prince-Henri .., ...... Luxembourg ............ .................................................. ................................ (io) seeks the grant of a patent for the invention described and represented in the abovementioned annexes, - with postponement of this issue to ....... ^ .. 1. ^. “™ ..? .. ™ ...... months.

.....

* - II. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of National Economy and the Middle Classes, Industrial Property Service in Luxembourg, dated: 27 d * csnbre 1378

Pr. The Minister at 15 ··. · 0 ü hours / '\ of the National Economy and' key Middle Classes, \ B;: SV ù c / ^ p LA C3îj07 _. · -> __ / / __ / 1 \ TTf-.VA v.mAvî rt «, fi vtv. Q odrûnft Λ / 0 \ f * i T TT Tir., 1 V. rt M ·. ΛΑ λ1% “Ί? 4 m r.i-, ΐηΧηΪΜΗ Jt.

DESCRIPTION MEMORY filed in support of a PATENT D1INVENTION in the name of Guido VERHA.EGHE for: "Process for the manufacture of Laminated panels”.

The invention relates to a method for manufacturing laminated panels, more particularly laminated glazing.

Laminated glazing is glazing in which one or more layers of glass or plastic similar to glass are alternated with one or more sheets of a thermoplastic interlayer.

The most common in this application is plasticized polyvinyl butyral. These types of glazing are used for cover / - 2 - 1 ’mirrors and windshields for aircraft and tanks, and safety glazing for buildings. The number and thickness of layers of glass or similar plastic material and the number and thickness of layers of thermoplastic interlayer may vary according to the specific needs of one or other particular application.

Usually, the production of laminated glazing is done in several stages, two of which are particularly important, namely: 1 ° degassing or pre-bonding, 2 ° treatment in an autoclave, called "autoclaving", or final bonding.

1. The degassing or pre-bonding of laminated panels, in particular laminated glazing commonly known as laminated, is carried out in such a way that most of the gases, which have been enclosed between the different layers during assembly, are evacuated. Simultaneously with this evacuation, a laminate is pre-glued so as to seal the panels to prevent air or liquids from entering between the layers during the following manipulations, and in particular during autoclaving.

There are several methods of degassing or pre-bonding.

> One of the most widespread methods is calendering, in which the assembled laminates are alternately subjected to heating, usually at temperatures between 40 ° C and 130 ° C, and a passage between rollers of 'a grille.

During said passage the gases are pressed outwards and a pre-bonding of the individual layers develops / i - 3 - t \ »* at the same time as a sealing of the edges.

This can be done in several stages in order to be able to optimize the process, in particular in that it concerns a complete sealing of the edges without causing pockets of gas trapped in the laminate.

This is particularly important when you want to prevent bubbles from appearing in the finished product.

Other methods for degassing or pre-bonding consist of evacuating the gases through rubber rings, sealed bags, or sealed chambers in which a vacuum is applied to the interstices of the laminate. The laminates are then subjected to heating in a heated tunnel or an oven.

Finally, there is also a method according to which one operates by vacuum heating directly in the autoclave, without having recourse to rings or bags. This latter degassing and pre-bonding method is very delicate in its application due to the very limited bonding and sealing forces, which often results in excessive waste rates.

In addition, this latter method is also very sensitive to changes in rheology, such as plasticity and * viscosity, of thermoplastic interleaves and to defects in parallelism in the individual layers.

In addition, the thermal conductivity under vacuum is low and gives rise to excessively long cycles in the autoclave * 4 - coupled with high energy consumption.

2. Autoclaving or final bonding: The purpose of this step in the manufacture of laminated glazing is to achieve intimate contact and bonding between the different components. At the same time, there is an almost total relaxation of the tensions in the thermoplastic interlayer which simultaneously absorbs the remaining air, gas and humidity which were still present between the layers of the laminate. This is done at high pressures and temperatures. In the case of a plasticized polyvinyl butyral interlayer, these pressures are generally of the order of 10 to 15 atmospheres, at temperatures of the order of 130 ° C. to 150 ° C.

The present invention relates to a method which makes it possible to combine either partially or completely the step of! degassing and pre-bonding with the autoclaving and bonding stage, in a single operation. The main advantages of this! 1 method are as follows: - a significant reduction in energy consumption due to the fact that the laminate has to be heated only once; - a significant reduction in manpower since the number of manipulations is reduced as a result of the elimination of the pre-. bonding, and the total elimination of the use of pliers or a special roller which is used to better seal the edges to avoid penetrations during autoclaving; - a significant reduction in waste which is often the result of handling, especially in the case of calendering which frequently causes glass breakage; S] i - a significant reduction in waste due to the inclusion of / - 5 - - a significant increase in reproducibility with regard to the long-term stability of the laminates. This is the result of a more complete and more reproducible degassing. corn.

„What is claimed in the present patent application is a method which is based on the principle of a simultaneous application of a vacuum to the interstices of a laminate, and of a pressure with heating in an autoclave on the outside of the laminated, all by going through the three usual stages of an autoclave cycle. These three stages are as follows: the stage of pressure and temperature rise. , the step of maintaining temperature and pressure at nominal values, and the step of cooling and reducing pressure.

The particularities of the claimed method are as follows: A method is used by which the laminate is enclosed in a flexible and waterproof bag or envelope inside which a relatively high vacuum is applied.

Having thus evacuated practically all the air, the envelope is sealed. Then, the envelope is introduced into the autoclave: the autoclave is closed and the normal autoclaving cycle is applied by going through the three normal stages. autoclaving, namely: 1. The step of pressure and temperature rise.

2. The step of maintaining the pressure and the temperature at a nominal value.

3. The cooling and pressure reduction step. / - 6 - t. ",

NOT

According to the method of this invention, a flexible packaging material is used having a melting or distortion point higher than the temperature of pre-bonding or sealing of the thermoplastic interlayer in the laminate.

Another feature of this flexible packaging material is that it shrinks by heat at temperatures which are considerably lower than its melting or distortion point. Under the effect of this shrinking by the heat produced during the first autoclaving step, the sealed flexible packaging in which there is a vacuum, fairly high, comes into intimate contact with the laminate. Consequently, this packaging will follow, to a few degrees, the same rise in temperature as the laminate, even if the air circulating in the autoclave is appreciably warmer. This prevents certain parts of the packaging, in particular the welded or sealed edges, from rising too quickly in temperature with the risk of distortion or premature disintegration and loss of tightness that this would imply.

Another characteristic of this flexible packaging material is that it can have a melting or distortion point which is lower than the maximum temperature used during the second autoclaving step. Another characteristic of this flexible packaging material is that it must remain gas tight and therefore keep the vacuum up to the temperature of pre-gluing or sealing of the laminate. Yet another basic feature of this flexible packaging material is that it is an inexpensive, easy to manufacture product. It is on this last point that other methods described in the literature or known by the initiates and which used waterproof bags going through the three stages of autoclaving have most often failed in practice, their use, even manufacturing being too expensive in raw materials or labor.

Furthermore, the flexible packaging material used according to the invention is easy to remove from the laminate after autoclaving, this mistletoe implies that it does not excessively adhere to the laminates at temperatures close to its melting or distortion temperature. or above this temperature.

In addition, the flexible packaging material will preferably be self-extinguishing. A last important characteristic of flexible packaging material is that it must be easily sealed after evacuating the air according to current "heat seal" methods, thus allowing the use of simple and inexpensive equipment used in the vacuum packaging industry. All these characteristics are combined in the present invention by a judicious choice of materials making up the flexible packaging. As the preferred type of material, a biaxially oriented polyolefin film is used at temperatures substantially below the distortion or melting temperature. This polyolefin film will then be coated with a thin layer of polyvinylidene chloride of a high degree of purity and, consequently, of a * * - 8 -

A preferred example of implementation of the process of the invention is given below.

Example.

As shown in FIG. 1, a film of polyolefin, and preferably of polypropylene 2, known for example under the trade name "biaxially oriented" Eltex, with a thickness of the order of 15 to 60 μm (i and preferably between 20 and 40yM with a shrinkage rate of the order of 5 to 30% and preferably between 8 and 15% at temperatures of the order of 50 to 140 ° C and preferably between 60 and 110 ° C. In the case of this particular example, the biaxially oriented polypropylene film is made sealable by "heat seal", the characteristics of "heat seal" being obtained through a coating such as, for example, of polyethylene 1 coextruded with polypropylene 2 and with a thickness of the order of 10 / f and preferably between 2 and 6. Then a gas-tight layer is applied. The preferred method consists in coating a polyvinylidene chloride latex 3 of high purity such as the product known under the trade name "Ixan" from the firm Solvay or a pr equivalent odor.

Very pure polyvinylidene chloride latex has the characteristic that it produces layers much more impermeable to gases than ordinary plastic films, including extruded polyvinylidene chloride films, because of the additives required for extrusion. This layer coated with polyvinylidene chloride latex (PVDC) was

Tl - - _i_ Λ i ^ ra A ^ Λ V · "» / ^ 4- 1- r ··? R> T * ·! / 3 t (_ 9 - polyvinylidene chloride. Of particular importance is the fact that the crystallization of PVDC develops particularly well by traversing a temperature range between 60 and 90 ° C and this at speeds of the same order of magnitude as the heating speed of an air autoclave during the first autoclaving step This allows the use of very thin and therefore inexpensive PVDC coated layers. Typically, PVDC layers of the order of 1 to 8 μM and preferably 2 to 5 μm are used. This coating can be carried out either on one side or on both sides of the polyolefin film. In order to manufacture laminates according to the method of the present invention, a special film j is used as flexible packaging using the following process: ί ri It is a question of manufacturing a laminated glazing from a sheet of glass of a thickness which can vary depending on the final application between 0.5 and 12 mm., one or more sheets of plasticized polyvinyl butyral which vary in thickness between 0.30 | and 1.50 mm, and another sheet of glass similar to the; first. As shown in Figure 3, we start by expanding; a piece A of said flexible polypropylene packaging material - 1 _ biaxially oriented lene 2 and coated with polyvinyl chloride - | idene 3. The piece of flexible packaging material A will have a surface area which exceeds twice the surface area of the glazing to be wrapped. The face i ~ coated with polyvinylidene chloride 3 will be directed downward. The glass B / B /, 9 Λ * - 10 - will be assembled by superimposing the three layers, glass 4, polyvinyl butyral film 5 and glass 6 on the piece of flexible packaging material A (see figure 2). Then, we proceed to the sealing by "heat seal" of the three edges which have remained open while simultaneously evacuating the air by the vacuum packaging method by "heat seal" (see Figure 4). Evacuation will take place at a vacuum of the order of - 300 to -700 mm. Hg and preferably between -500 and -600 mm. Hg. The heat seal is carried out at temperatures of the order of 130 to 180 ° C and preferably between 135 and 155 ° C. A hot sealing method will be used which at the same time allows the excess of flexible packaging material to be separated, as shown in FIG. 5. The packaging thus obtained is introduced into the autoclave. The autoclave is closed and the first autoclaving step is carried out, gradually increasing the pressure and the temperature during a period which can vary between 15 and 200 minutes, and preferably between 30 and 60 minutes. It is during this step that we will obtain a seal and pre-glue the laminate. In the case of a commercial polyvinyl butyral film, this sealing will develop approximately from 45 ° C. and will be complete between 70 and 100 ° C., depending on the speed at which the temperature and pressure are increased. Since the flexible packaging material according to this invention retains all of its waterproof qualities up to temperatures above 70 ° C. there will be practically no gas penetration / 4 m O.

-The autoclave inside the degassed laminate. It is at this stage that we also take advantage of the shrinking properties of the packaging since the temperature of this packaging will in no place exceed the temperature of the laminate by more than a few degrees, because of intimate contact over its entire surface. as illustrated in figure, 5, and will therefore remain gas tight until the laminate has reached its sealing temperature. We can therefore continue to increase in temperature and pressure until the conditions for the second autoclaving stage are obtained. These conditions are of the order of 120 to 160 ° C and preferably of 135 to 150 ° c for the temperature and of the order of 6 to 15 bars and preferably of 10 to 14 bars for the pressure. In the event that from a temperature above the polyvinyl butyral sealing temperature, the flexible packaging begins to lose its waterproofing qualities, this will no longer have any negative effect on the quality of the laminate. The autoclaving is therefore continued by going through the second step during which the conditions already described are maintained for a period which varies according to the thickness of the glazing, their shape and the characteristics of the autoclave between 10 and 180 minutes and preferably between 15 and 25 minutes. Then, we go through the third autoclaving step during which we proceed to the cooling and the pressure drop. We will take care not to drop the pressure too suddenly and preferably we will simply limit ourselves to cooling the autoclave which, by / \ / / \ / //

Claims (20)

1.- What is claimed in the present patent application is a method which is based on the principle of a simultaneous application of a vacuum to the interstices of a laminate, and pressure and autoclave heating on the outside the puff pastry, all by going through the three habitual stages of an autoclave cycle. / /. • V - 13 - The vacuum at the interstices of the laminate is obtained by the use of a waterproof bag subjected to vacuum and sealed afterwards. The material used for this waterproof bag is a thin layer of polyvinylidene chloride applied on a support film . The polyvinylidene chloride is of high purity and is characterized by the fact that its gas tightness increases with the degree of crystallization, degree of -crystallization which in turn increases with the purity and slowly increasing the temperature to 80 to 90 ° C. 2. A method according to claim 1, characterized in that the layer of polyvinylidene chloride is coated with a latex or similar product. 3. A method according to either of the preceding claims, characterized in that the support film is a polyolefin film. 4. A method according to any one of the preceding claims, characterized in that the polyolefin support film is biaxially oriented and shrinking at temperatures well below its melting or distortion temperature. 5. Method according to any one of the preceding claims, characterized in that the polyolefin film is composed of a layer of polypropylene and a layer of coextruded polyethylene. 5. A method according to any one of the preceding claims, characterized in that the propyolefin support film is composed of a layer of polypropylene and of two layers of polyethylene, the polypropylene being Z A - 14 - " 7. A method according to any one of the preceding claims, characterized in that the waterproof bag is sealed by heat sealing. 8. A method according to any one of the preceding claims, characterized in that the layer of polyvinylidene chloride is oriented towards the outside of the package, and this in order to obtain self-extinguishing characteristics in the case autoclave fire. 9. Method according to any one of the preceding claims, characterized in that a layer of polyvinylidene chloride is applied to each side of the polyolefin film. 10. Method according to any one of the preceding claims, characterized in that several laminates are superimposed one on the other inside the flexible packaging. This can be done without difficulty in the case of flat laminates, unlike what is possible for curved laminates. This allows considerable savings in the consumption of flexible packaging material, and in labor for preparation, sealing and other handling for the preparation of flexible packaging. 11. Method according to any one of the preceding claims, characterized in that a layer of porous material is interposed between the laminate and the flexible packaging, such as for example paper, textile, or nonwoven, and this for the purpose to obtain easier passage of enclosed gases / - 15 - k · * "and mistletoe must be evacuated to the vacuum duct. In the case of the use of flexible packaging material with a tendency to stick too strongly on the glass after autoclaving, this additional layer can also serve as an anti-adhesive. 12, - A method according to any one of the preceding claims, characterized in that a plastic product is used as a substitute for glass such as for example poly-methylmetacrylate or polycarbonate. 13, - A method according to any one of the preceding claims, characterized in that mixed compositions of glass and glass substitutes are used, either in two layers or multiple layers. 14, - A method according to any one of the preceding claims, characterized in that thermoplastic spacers other than plasticized polyvinyl butyral are used, such as for example polyurethanes, polyesters, acrylics or polyolefins. 15, - A method according to any one of the preceding claims, characterized in that produced asymmetric laminates and in particular sheets for automobile windshields using a very thin glass layer as an inner layer. 16, - A method according to any one of the preceding claims, characterized in that it is applied for / the manufacture of composite laminates. / / - 16 - Λ * ♦ 17. A compound laminate manufactured according to the method of one of the preceding claims. 18. A method for manufacturing laminated panels, characterized in that it consists in surrounding one or more laminated sheets comprising several superimposed sheets of glass, or transparent plastic material alternated with one or more sheets of a thermoplastic interlayer in an envelope or bag made of flexible and gas-tight material, to create a relatively high vacuum inside this envelope, to completely close this envelope, to gradually increase the pressure around the envelope and simultaneously increase the temperature of the medium in which it -this is up to determined pressure and temperature values, to maintain this pressure and this temperature for a certain time and then simultaneously and gradually reduce this temperature to around ambient temperature and atmospheric pressure 19. The method of claim 18, characterized in that an envelope or bag is used which can shrink under the effect of heat. 20. Method according to either of claims 18 and 19, characterized in that the pressure around the envelope is increased while applying the aforementioned vacuum inside thereof. 21. Method according to any one of claims 18 to 20, characterized in that an envelope is used / obtained according to the method described above. //. · ”- 17 - 22. Method according to any one of claims 18 to 21, characterized in that it consists in using a single-use envelope. 23. Method according to any one of claims 18 to 22, characterized in that it consists in carrying out "degassing at room temperature. 24. Laminated panel obtained by implementing the method described above or shown in the accompanying drawings. 25. Method for manufacturing laminated panels as described above, more particularly in the example given in the description. Soothsayers: ........ 5 .......... p! Cnÿ "~ s 4t ...... es.-s cîjrit J .......: —Λ - Γ - 3, ....... '' Λ - .....; l - ï-'i-VZndcSfciOrt- ... /; ^ G ^ criptif Lux'in'iHr: ':' ',! 2 DEC 27 1 ^ 78 ^' Charles München i