DE19643404A1 - Process for the production of composite safety washers - Google Patents

Abstract

The present invention relates to a method for producing in one step laminated safety glass windows made of at least two glass panes and a partially acetalised polyvinyl-alcohol interlayer containing a plasticizer. According to the non autoclave method, a foil of partially acetalised polyvinyl alcohol is used which contains a plasticizer and less than 0.35 w-t % of water in relation to the foil mass and an effective quantity of functional organosilicone which increases adhesion.

Description

Technical field

The invention relates to a method for producing ver collar safety washers consisting of at least two glass slices and an intermediate layer of plasticized partially acetalized polyvinyl alcohol, in a one-step, autoclave-free process.

Laminated safety panes, consisting of two glass panes and an adhesive film connecting the glass panes, preferably Made of polyvinyl butyral (PVB), are used especially as wind protection discs used in motor vehicles, where appropriate a glass pane through a plastic pane, mainly made of an amorphous polyamide, transparent PMMA, polycarbonate or Polyester, can be replaced. Also in the construction sector, e.g. B. as Window panes or as partitions, such silicate Glass / silicate glass or silicate glass / plastic composites inserted sets, where appropriate depending on their use, for. B. as Compound armored glass, also multiple composites, i.e. composites that consist of more than two load-bearing layers, who are used the.

While composite safety washers for construction i. a. a have the highest possible adhesion between glass and adhesive film should be used for composite safety windows for motor vehicles a defined, not too high liability is sought.

State of the art

For the production of composite safety washers, my used a two-stage manufacturing process. In one The first step is a so-called preliminary network consisting of the two panes of glass and the adhesive between them foil, usually made of PVB. This preliminary network in a second process step in an autoclave Temperatures of approx. 130-145 ° C and pressures of at least 11 bar pressed to the actual composite safety washer. This procedure is described, for example, in the introduction to EP 0 331 648 A2. The water content of the used PVB film significantly influences the bond strength of the composite.  

A water content of 0.40 to 0.55% by weight is usually used. the film - with very low tolerances - adhered to. Conditionally through the use of an autoclave this well-known two stage fen process is relatively complex and requires a high level of investment on, so that it is unprofitable for small production quantities.

EP 0 331 648 A2 discloses an autoclave of the generic type there are processes for the production of composite safety disks knows. In this known method, the glass panes with the intermediate PVB film in an airtight, eva chopped sack at elevated temperature through the outside air pressure glued together. From this document is also knows that the PVB film used to avoid bubbles should have the lowest possible water content in the network. However, the achievable adhesion is between the layers of the association, especially for the construction sector, not always sufficiently high.

DE 24 10 153 C3 describes a method for adjusting the Adhesion of plasticized partially acetalized polyvinyl alcohols with silicon functional and silicon organofunction nellen silanes known, the silicon-functional silanes reduce the adhesion and the silicon-organofunctional silanes increase liability. The effect is al in conventional processes but not very high.

task

The object of the present invention is to provide a method for the manufacture provision of composite safety washers, consisting of at least at least two glass panes and an intermediate layer of soft ma partially acetalized polyvinyl alcohol, in one to provide staged, autoclave-free processes, that with sufficient process reliability to bubble-free composite leads to high liability safety washers, in particular the Meet requirements for the construction sector.

Presentation of the invention

The invention solves this problem by using a partially acetalized polyvinyl alcohol film containing plasticizer  with a water content of less than 0.35 wt .-%, based on the mass of the film, and an effective content of the haf tion-increasing silicon-organofunctional silane in one one-step, autoclave-free process.

The partially acetalized polyvinyl alcohols can be in itself known by saponification of polyvinyl acetate and closing acetalization with aldehydes, such as. B. Formalde hyd, acetaldehyde, propionaldehyde, butyraldehyde and the like. Like. Herge be put. They usually still contain about 0.5 to 5 Ge percent by weight, in particular about 0.5 to 1.2 percent by weight, Acetyl groups, calculated as vinyl acetate residues. Other buttocks too lyvinyl esters of aliphatic acids with up to 9 carbon atoms can be saponified and then acetalized. Sub-duty Rized polyvinyl alcohol (PVB) is preferably used. With regard to the polymers that can be used, the DE 24 10 153 C3 referenced.

The film used for the process according to the invention ent holds plasticizers in amounts of preferably 20 to 40% by weight. Examples of plasticizers that can be used are triethylene glycol di (2-ethylbutyrate), di-n-hexyl adipate (DHA) and preferably Trie bhylene glycol bis-n-heptanoate (3G7).

According to the invention, the water content of the adhesive film is reduced to one Value of less than 0.35% by weight, preferably of the same or similar less than 0.30% by weight, based in each case on the mass of the film, set. The water content to be observed according to the invention serves to avoid bubbles in the finished product Composite safety washers, it affects together with the set silicon-organofunctional silanes beyond the adhesion between the adhesive film in a synergistic manner and the glass panes.

The sili used to increase adhesion cium organofunctional silanes are in themselves z. B. from the DE 24 10 153 C3 known, so that herewith reference to this document can be taken.  

During the addition of silicon to increase adhesion organofunctional silanes in the usual autoclave process only has caused a moderate increase in film / glass adhesion surprisingly found that the same silane compounds when using an autoclave-free procedure one more have a higher effect. This is explained below using Examples and comparative examples as well as the drawing ver clearly.

Brief description of the drawing

It show

Fig. 1 shows the pressure and temperature curves vs. Time after example 1, 2 and comparative example 3;

FIG. 2 shows the pressure and temperature curves vs. Time according to comparative examples 4 to 6;

Fig. 3 is a schematic representation of a Versuchseinrich device for a compression shear test.

Ways of Carrying Out the Invention and Comparative Examples example 1 (according to the invention)

By a method according to EP 0 185 863 B1, example 1 a PVB adhesive film roughened on both sides. As Plasticizer becomes triethylene glycol bis-n-heptanoate (3G7) used. The plasticizer is called silicon organofunction nelles silane a γ-aminopropyltriethoxysilane in an amount of 0.03 wt .-%, based on the mass of the film, added. Of the The water content of the PVB adhesive film was reduced to 0.29% by weight poses. Two flat silicate glass panes and the PVB adhesive film are then processed in a single-stage, autoclave-free Va vacuum process as described in EP 0 331 648 A2, processed into a composite safety disc. The procedure parameters were there we follow:  

Table 1

The exact chronological sequence is shown in more detail in FIG. 1.

Example 2

Following the same procedure as in Example 1, composite Si made of safety washers, but with di-n-hexyl adipate (DHA) is used as a plasticizer.

Comparative Example 3

Following the same procedure as in Example 1, composite Si made of safety washers, but do not use silane det.

Comparative Examples 4 to 6

Large composite safety panes are produced as in Examples 1 to 3, but the composite is produced using the conventional two-stage autoclave process. The pressure and temperature curve is shown in Fig. 2.

Trial evaluation

The composite safety washers produced in this way are one Standard compression shear test subjected to a quantita tive assessment of glass / film adhesion allowed. In doing so the composite safety washers to be tested at an angle clamped from 45 ° in a two-part test apparatus. The above right half is followed by a steadily increasing, exactly vertical downward force applied until it abheses tion within the test specimen, d. H. the group to be checked safety disc, coming.  

The test device used for this is shown schematically in FIG. 3. The test parameters were as follows:

Table 2

For each example, the force exerted during shear is used averaged from ten identical test specimens. To assess the The spread of the individual measurements will continue to be the standard dard deviation of the individual measurements is calculated.

The test results are shown in Table 3. At in all examples a water content of approx. 0.29% by weight the film adhered to in the manufacture of the composite.  

Compression shear test results

Compression shear test results

A comparison of the results of Comparative Example 6 with Comparative Example 3 (bottom line in Table 3) shows that when using conventional adhesive films, the compression shear forces drop to about 30% of the initial value when using an autoclave-free process compared to an autoclave process. However, if you compare the results of Comparative Examples 4 and 5 with Examples 1 and 2 according to the invention (upper and middle lines in Table 3), there is almost constant liability when using an autoclave-free process compared to an autoclave process.

When comparing the results of Comparative Example 6 with comparative examples 4 and 5 (right column in table 3) which the well-known use of adhesive films with and without Silane additives in the conventional autoclave process concern, he do you know an increase in compression shear forces of approx. 12% or 22% through the silane additives. But if you compare the results nisse of comparative example 3 with the case according to the invention if you play 1 and 2 (middle column in table 3), you get in the autoclave-free process, an increase in liability by the addition of the silanes of 250% or 330%, that is more than Ten times the effect of the silane additives in the autoclave-free Process!  

This effect of the known silane additives is complete surprised. It enables the autokla known per se ven-free process for the production of composite safety washers open up a wider application. In particular, it is there with also possible composite safety washers for the construction area to manufacture with higher process reliability.

Claims (5)

1. A process for the production of composite safety panes, consisting of at least two glass panes and an intermediate layer of plasticized partially acetalized polyvinyl alcohol, in a one-step, autoclave-free process, characterized by the use of a plasticized partially acetalized polyvinyl alcohol film

• - A water content of less than 0.35 wt .-%, based on the mass of the film, and
• - an effective content of a silicon organofunctional silane which increases the adhesion.

2. The method according to claim 1, characterized by the use of a silane of the formula
in the

• - R a hydrolyzable residue
• R 'is an alkyl radical having 1 to 18 carbon atoms,
• - A is a divalent alkylene radical with 1 to 10 carbon atoms, which can optionally be branched, and
• Z is a functional residue selected from the group consisting of
  where R is H or aminoalkyl having 2 to 8 carbon atoms in the alkyl radical and R '''is H or R'', and
• - n = 1 to 3 and
• - p is 1 or in the case of Z = -CH = CH ₂ is 0.

3. The method according to claim 1, characterized in that as silicon organofunctional silane γ-aminopropyltriethoxy silane is used. 4. The method according to claim 1, characterized in that the silicon organofunctional silane in an amount of 0.01 up to 0.06% by weight, based on the mass of the film is set. 5. The method according to claim 1, characterized in that as partially acetalized polyvinyl alcohol is a polyvinyl butyral resin with 12 to 25 wt .-% vinyl alcohol residues used becomes.