Stock material or miscellaneous articles – Composite – Of quartz or glass
Reexamination Certificate
2001-02-22
2004-03-23
Lipman, Bernard (Department: 1713)
Stock material or miscellaneous articles
Composite
Of quartz or glass
C428S442000, C528S319000
Reexamination Certificate
active
06709750
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a new hot-melt adhesive for sealing the edge of laminated glass that is produced by means of casting-resin technology, a method for the preparation thereof, and also uses of this hot-melt adhesive.
Laminated glass consists of at least two glass panes and one intermediate layer which connects the glass panes with one another. The glass panes can be selected from inorganic glass, such as float glass, colourless glass, single-pane safety glass, partly tempered glass, coloured glass, coated glass, mirror-coated glass and thin-film solar modules, and from organic glass, such, as, for example, glass made from polymethacrylate or polycarbonate, with it also being possible to combine with one another glass panes that are made of different types of glass.
Laminated glass is used, for example, as laminated glass with safety and/or sound-proofing properties, as fire-protection glass, as laminated glass with temperature-dependent variation of its light-transmitting capacity, when sealing objects in the interspace between the panes of the glass composite (for example solar cells or lamellar systems, which are used to protect against insolation or for looking through, are sealed in the interspace between the panes), or for the protection of surfaces by bonding to the surface with one glass pane (planar surfaces (for example marble) are protected in this way for example).
One common method for producing laminated glass involves filling a prepared glass-plate composite, which is sealed in the edge region, with a liquid casting resin that is cured under suitable conditions (for example under ultraviolet light, thermally or by means of redox-initiators). Casting resins that do not need to be cured and which have sufficient stability on account of their thixotropic properties, for example, can also be used for the production of laminated glass.
The cured casting resin can be transparent, coloured or turbid or can become turbid as a function of the temperature, and can contain, for example, silicone, polyurethane, polyester, polyether or polyacrylate as the main constituent.
The edge seals that are usually used for the production of laminated glass by means of casting technology are designed as butyl cords and adhesive tapes with thicknesses between 1 and 3 mm. Butyl cords, which can contain a hard core that is made from a thermoplastic polymer (for example polypropylene), consist, for example, of soft mixtures based on isobutylene-polymers and carbon black. Either foam tapes that are coated on both sides with contact adhesive and which are based on polyacrylate (ex 3M), polyethylene (ex Norton and Vito) or polyurethane (ex Norton) or else self-adhesive transparent solid tapes, consisting of polyacrylate (ex 3M), can be used as the adhesive tapes. Butyl cords and adhesive tapes are usually laid at the edge region of a glass plate by hand, the second plate is then laid on top, and the composite is finally pressed in a surface press until there is contact. The liquid casting resin is poured in through a piece that is left free in the edge seal (feed opening) and this resin can then be cured after the feed opening has been sealed by means of a further material (for example hot-melt adhesive based on ethylene vinyl acetate copolymer (EVA)).
The disadvantage, in this connection, is the manual application of the edge seal, and, moreover, problems of compatibility can arise between the casting resin and the sealing material for the feed opening. The process of sealing the edge by means of a butyl cord is, to a great extent, prone to allow a run-out during the filling and curing process, since the casting resins can easily infiltrate the boundary layer between the glass and butyl. In addition, the black colour of the butyl is perceived to be unpleasant. Furthermore, butyl cords, on account of the hard core, and adhesive tapes, in view of the high level of elasticity, have the disadvantage that they do not reduce the tensions which develop at the edge region of the layer of casting resin during the curing as a result of the contraction through polymerization, since it is only by plastically deforming the edge seal that tensions can be permanently reduced.
An improved edge seal is possible with the so-called “TPS-system”, in which a strand-of a material that can be processed thermoplastically, and which is based on isobutylene-polymers and carbon black, is automatically extruded onto a first glass plate by means of a suitable machine with variable strand thickness, the second glass plate is laid on top and then, by means of a surface press, this is pressed until there is a predetermined interspace. As described above, a casting resin is poured in through a feed opening, the feed opening is sealed by means of a hot-melt adhesive, and the casting resin is cured. It is disadvantageous in this connection, that the material that is used for the edge seal is too firm to reduce tensions at the edge region of the layer of casting resin completely. In addition, the black colour of the edge is strikingly unpleasant, since as a rule casting resin is transparent or translucent. Moreover, problems of compatibility with the hot-melt adhesive can also arise in the case of this laminated glass.
SUMMARY OF THE INVENTION
The underlying object of the invention is therefore to overcome the disadvantages of the prior art and develop a new hot-melt adhesive for sealing the edge of laminated glass produced by means of casting-resin technology and also to provide a method for the preparation of the new hot-melt adhesive.
The object is achieved by means of a hot-melt adhesive which consists of homopolymers or copolymers of acrylates or methacrylates, or mixtures thereof or which contains homopolymers or copolymers of acrylates or methacrylates, or mixtures thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The hot-melt adhesive in accordance with the invention consists of homopolymers or copolymers of acrylates or methacrylates, or mixtures thereof. The homopolymers or copolymers of acrylates or methacrylates, which are also called poly(meth)acrylates, are, as a rule, polymers of the esters of acrylic acid or methacrylic acid and can contain as alcohol constituents an alkyl group, substituted or unsubstituted by functional groups, for example methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl and hexyl and their isomers and higher homologues, 2-ethyl hexyl, phenoxy ethyl, hydroxyethyl, 2-hydroxypropyl, caprolactone hydroxyethyl or dimethylaminoethyl. The homopolymers and copolymers of acrylates or methacrylates can also contain the monomers acrylic acid, methacrylic acid, the amides of the acids mentioned and acrylonitrile, and also in small quantities (<5%) further monomers, such as olefins (for example ethylene or propylene) or functional vinyl compounds (for example vinyl acetate, styrene, &agr;-methyl styrene or vinyl chloride). It is also possible to use partly cross-linked poly(meth)acrylates, in which the cross-linkage is effected by way of a multi-function monomer with, for example, diethylene glycol or trimethylol propane as the alcohol constituents, and mixtures of the homopolymers and copolymers of acrylates or methacrylates.
The hot-melt adhesive in accordance with the invention according to claim
1
consists of homopolymers or copolymers of acrylates or methacrylates, or mixtures thereof. The homopolymers or copolymers of acrylates or methacrylates, which are also called poly(meth)acrylates, are, as a rule, polymers of the esters of acrylic acid or methacrylic acid and can contain as alcohol constituents an alkyl group, substituted or unsubstituted by functional groups, for example methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl and hexyl and their isomers and higher homologues, 2-ethyl hexyl, phenoxy ethyl, hydroxyethyl, 2-hydroxypropyl, caprolactone hydroxyethyl or dimethylaminoethyl. The homopolymers and copolymers of acrylates or methacrylates can also contain the monomers acrylic acid, methacryli
Pohlmann Thomas
Schwamb Michael
Antonelli Terry Stout & Kraus LLP
Lipman Bernard
Metallgesellschaft Aktiengesellschaft
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