MXPA00011865A - Hot-melt adhesive for sealing the edge of laminated glass - Google Patents

Abstract

The invention relates to a hot-melt adhesive for sealing the edge of laminated glass that has been produced according to cast-resin technology. The inventive adhesive comprises acrylate or metacrylate homopolymers or copolymers or mixtures thereof. The invention also relates to a method for the production and to the uses of said hot-melt adhesive.

Description

HOT FUSION ADHESIVE TO SEAL THE LAMINATED GLASS EDGE FIELD OF THE INVENTION 5 The present invention relates to a new hot melt adhesive for sealing the edge of laminated glass that is produced by means of molding resin technology, a method for the preparation thereof, and also the uses of this hot melt adhesive. BACKGROUND OF THE INVENTION Laminated glass consists of at least two sheets of glass and an intermediate layer connecting the glass sheets together. The glass sheets can be selected from inorganic glass, such as float glass, glass colorless, single-pane safety glass, partially tempered glass, colored glass, coated glass, mirror-coated glass and thin film solar modules, and organic glass, such as, for example, glass made of polymethacrylate or polycarbonate, being also can be combined with other glass sheets that are made of different types of glass. Laminated glass is used, for example, as laminated glass with safety properties and / or sound insulation, such as fire protection glass, as laminated glass with variation of its transmission capacity -------------- -db-t-ük- ^ i-iy-iái-ta-k-1 light-dependent temperature, when objects are sealed in the inter-space between composite glass sheets (eg solar cells or lamellar systems, which are used for protection against insolation or to look through, are sealed in the interspace between the sheets), or for the protection of surfaces by joining the surface with a layer of glass (flat surfaces (eg marble) are protected in this way for example). A common method for producing laminated glass includes filling a composite prepared glass plate, which is sealed in the edge region, with a liquid molding resin that hardens under suitable conditions (e.g. under ultraviolet light, thermally or by means of initiators). redox). Molding resins that do not need to harden and that have sufficient stability due to their thixotropic properties, for example, can also be used for the production of laminated glass. The hardened molding resin may be transparent, colored or cloudy or may become cloudy as a function of temperature and may contain, for example, silicone, polyurethane, polyester, polyether or polyacrylate as the main constituent. The edge seals that are normally used for the production of laminated glass by means of molding technology are designed as butyl cords and adhesive tapes with thicknesses between 1 and 3 mm. The butyl cords, which may contain a hard core which is made of a thermoplastic polymer (for example polypropylene), consist, for example, of soft mixtures based on polymers of isobutylene and carbon black. Any of the foam tapes that are covered at both ends with contact adhesive and which is based on polyacrylate (ex 3M), polyethylene (ex Norton and Vito) or polyurethane (ex Norton) or 10 also self-adhesive transparent solid tapes , which consist of polyacrylate (ex 3M), can be used as adhesive tapes. The butyl cords and the adhesive tapes are usually placed in the edge region of a glass plate by hand, the second plate is then placed on top, and the compound is finally pressed in a surface press until contact exists. The liquid molding resin is poured through a piece that is left free in the edge seal (feed opening) and this resin can then be hardened after the feed opening has been sealed by means of an additional material (for example). Example of hot melt adhesive based on ethylene vinyl acetate (EVA) copolymer). The disadvantage in this connection is the manual application of the edge seal, and in addition, compatibility problems may arise between the molding resin and the backing material. -tBiÍ-k - ^ - -M- - -É - ^ - »- iM-ll - ^ ---» lÉ- * tr¡¡ ?? l -m i- * Mr? ti ri ní ..ni, it > , i,, - sealed by the feed opening. The process of sealing the edge by means of a butyl cord is, to a greater degree, prone to allow an exit during the filling and curing process, since the molding resin can easily infiltrate the boundary layers between the glass and butyl. In addition, the black color of the butyl is perceived as unpleasant. In addition, butyl cords, because of the hard core and the adhesive tapes, in view of the high level of elasticity, have the disadvantage that they do not reduce the stresses they develop in the edge region of the molding resin layer during curing as a result of the shrinkage through polymerization, since only by plastically deforming the edge seal can these stresses be permanently reduced. SUMMARY OF THE INVENTION 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 polymers of isobutylene and carbon black, is automatically extruded in a first glass plate by means of a suitable machine with variable strand thicknesses, the second glass plate is placed in the upper part and then, by means of a surface press, this is pressed until there is an interspace predetermined. As described above, a molding resin is poured through a feed opening, the feed opening is sealed by means of a hot melt adhesive and the molding resin hardens. It is disadvantageous in this connection that the material used for the edge seal is too firm to completely reduce the stresses in the edge region of the molding resin layer. In addition the black color of the edge is impressively unpleasant, since as a rule the resin of molding is transparent or translucent. In addition, compatibility problems with hot melt adhesive may arise in the case of this laminated glass. The underlying objective of the invention is therefore to overcome the disadvantages of the prior art and to develop a new hot melt adhesive for seal the edge of the laminated glass produced by means of molding resin technology and also provide a method for the preparation of the new hot melt adhesive. The goal is achieved by means of an adhesive Hot melt as specified in claim 1 or claim 2 and consisting of homopolymers or copolymers of acrylates or methacrylates, or mixtures thereof or containing homopolymers or copolymers of acrylates or meta-acrylates or mixtures thereof. The claim 3 specifies a further development of the ^ Hgg ^ -H -i-MÉÉ- -É hot melt adhesive according to the invention; claims 4 and 5 specify a method for the preparation of the hot melt adhesive according to the invention, and claims 6 to 8 relate to the use of the hot melt adhesive according to the invention. The hot melt adhesive according to 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 (meta) acrylates, are, as a rule, polymers of the esters of acrylic acid or methacrylic acid and may contain as an alcohol constituent 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 major homologs, 2-ethylhexyl, phenoxyethyl, hydroxyethyl, 2-hydroxypropyl, caprolactone hydroxyethyl or dimethylaminoethyl. The homopolymers and copolymers of acrylates or methacrylates can also contain the monomers of acrylic acid, methacrylic acid, the amides of the mentioned acids and acrylonitrile and also in small amounts (<; 5%) of additional monomers, such as olefins (for example ethylene or propylene) or functional vinyl compounds (for example vinyl acetate, styrene, α-methyl styrene or vinyl chloride). It is also possible to use partially degraded poly (meta) acrylates, in which the degradation is effected by means of a multifunctional monomer with, for example, diethylene glycol or trimethylol propane as the constituents of alcohol and mixtures of the homopolymers and copolymers of acrylates or methacrylates . The hot melt adhesive according to claim 2 may additionally contain additional components, such as thermoplastic polymers, natural and synthetic rubbers, viscosity additives, softeners, adhesion promoters, stabilizers and strength-increasing fillers and not increase of resistance. Examples of thermoplastic polymers are polyolefins such as homopolymers and copolymers, produced outside the monomers of ethylene, propylene, n-butene and their major homologs and isomers, and of vinyl functional compounds, such as vinyl acetate, vinyl chloride, styrene and a-methyl styrene. Further examples are polyamides, polyimides, polyacetals, polycarbonates, polyesters and polyurethanes and mixtures of all the mentioned polymers. The hot melt adhesive according to the invention can, however, also be prepared without thermoplastic polymers. Natural and synthetic rubbers can be selected from the group of homopolymers of dienes, from the group of the copolymers and thermopolymers of dienes with olefins, and from the group of copolymers of olefins. Examples are polybutadiene, polyisoprene, polychloroprene, styrene-butadiene rubber, block copolymers with blocks of styrene and butadiene or isoprene, butyl rubber, high molecular weight polyisobutylene, ethylene vinyl acetate rubber (EVM), ethylene propylene rubber and ethylene propylene diene rubber (EPDM), for example with dicyclopentadiene or ethyldiene norbornene as the constituent diene. The rubbers can also be used in hydrogenated form and also in mixtures. The hot melt adhesive according to the invention can, however, also be prepared without rubber materials. The viscosity adhesives may be selected from the group of natural and synthetic resins and also from subsequently modified resins, which include inter alia hydrocarbon resins, colophonium and its derivatives, polyterpenes and their derivatives, coumaron-indene resins and phenolic resins and from the group of polybutenes, polyisobutenes and imperfect liquid rubbers (for example butyl rubber or EPDM) which can also be hydrogenated. The listed viscosity additive mixtures can also be used.

The hot melt adhesive according to the invention can, however, be prepared without viscosity additives. Examples of plasticizers are the esters of phthalic acid (for example di-2-ethyl hexyl-phthalate, disodium-phthalate, diisobutyl-phthalate or dicyclohexyl-phthalate), phosphoric acid (for example 2-ethyl hexyl -diphenyl-phosphate, tri - (2-ethyl hexyl) -phosphate or tricresyl phosphate), trimellitic acid (for example tri- (2-ethylhexyl) -trimellitate or tri-isononyl trimellitate), citric acid (for example acetyl tributyl citrate or acetyl triethyl citrate) or dicarboxylic acids (for example di-2-ethyl hexyl adipate or dibutyl sebacate). Mixtures of plasticizers can also be used. The hot melt adhesive according to the invention can, however, also be prepared without plasticizers. The adhesion-promoting substances may be selected from the group of silanes, which may include, for example, 3-glycidyl oxypropyl-trialkoxysilane, 3-amino propyl-trialkoxysilane, N-aminoethyl-3-amino propyl-trialkoxysilane, 3-methacryloxypropyl-trialkoxysilane, vinyltrialkoxysilane, isobutyltrialkoxysilane, 3-mercaptopropyltrialkoxysilane, the group of esters of siliconic acid for example tetralkyl orthosilicates and the group of metalates, for example tetralkyl titanates or tetralkylzirconates, and also the mixtures of the listed promoter substances . The hot melt adhesive according to the invention can, however, also be prepared without adhesion promoting substances. The stabilizers can be antioxidants of the sterically retarded phenol type (for example tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane) or the antioxidant type based on sulfur, such such as mercaptans, sulfides, polysulfides, thiourea, mercaptalos, thioaldeids, thioketones. UV stabilizers of the benzotriazole type, benzophenone type or HALS type (retarded light stabilizers) and also ozone protection agents can also be used as stabilizers. They can be used either alone or in mixtures. The hot melt adhesive according to the invention can, however, also be prepared without stabilizers. Examples of reinforcing and non-reinforcing fillers are pyrogenic silica and precipitated respectively, silica gel, precipitated or ground chalk (also treated surface), calcium oxide, clay, kaolin, talc, quartz, zeolites, titanium dioxide, glass fibers or zinc and aluminum powder and mixtures thereof.

Unless a dark color of the hot melt adhesive according to the invention is perceived as - inconvenient, it is also possible to use carbon black, carbon fibers or graphite. The hot-melt adhesive according to the invention can, however, also be prepared without fillers. If the hot melt adhesive according to the invention consists of a plurality of components, it is prepared by mixing the homopolymers and / or copolymers of acrylates and / or methacrylates with the additional components in a suitable mixing unit. If shear forces are required, the mixing unit may for example be a mechanical kneader, a twin screw extruder or a single screw extruder. If high shear forces are not required, the mixing can be carried out by means of a planetary dissolver, a blade mixer with a dissolver disk, a turbulence mixer or similar units. Whether high or low shear forces are required depending on the consistency of the starting materials and the respective product; in this way high shear forces are required in order to incorporate rubbers or reinforcing fillers. The mixing temperature is in the range of 40 ° C to 200 ° C, preferably in the range between 70 ° C and 180 ° C. Optionally, the mixing can be carried out in a protective gas or under vacuum. The hot melt adhesive according to the invention, can be used to produce laminated glass that is produced by means of molding resin technology, with the method including the following steps for the production of the laminated glass: - applying the hot melt adhesive according to the invention to the region of edge of a glass sheet by means of the suitable apparatus (for example an extruder or a barrel pump); placing a second sheet of glass in order to be congruent with it in the hot melt adhesive; pressing the laminated glass to a predetermined thickness; fill the interspace between the sheets with a molding resin; as a rule, seal the feed opening with a suitable material, for example the hot melt adhesive according to the invention; as a rule, hardening the molding resin under suitable conditions (for example by UV radiation treatment, thermally or by means of redox initiators); optionally, repeat the steps of the method in the case of laminated glass having more than two sheets of glass.

The hot melt adhesive according to the invention is processed in the usual equipment for the application of hot melt adhesive or by means of an extruder, with the processing temperature typically in the range between 40 ° C and 200 ° C, preferably between 70 ° C and 180 ° C. Advantageously, it is possible to fill the interspace between the sheets with a molding resin by means of a feed opening which must subsequently be sealed by means of a suitable material (advantageously by means of the hot melt adhesive according to the invention, but also, for example, by means of another hot melt adhesive which is normally used). Other filling methods operate by means of one or more needles (for example, a needle comb) which is guided through the edge seal, with at least one needle advantageously inserted through the edge seal for the purpose of improved ventilation . If thin needles are required for backfill purposes, the openings through the edge seal can seal themselves on themselves or can be sealed by manual deformation of the edge seal. The hot melt adhesive according to the invention has the following functions in laminated glass: - as a seal for the interspace between the sheets of laminated glass, in the case of resin molding systems which harden during the filling process with molding resin and subsequent hardening or in the case of resin molding systems that do not need to harden during and after the filling process with molding resin; as spacers for the interspace between sheets of laminated glass with a high plastic content in order to reduce the stresses that develop during curing in the edge region of the molding resin layers. If the hot melt adhesive also contains fillers that are used simultaneously as drying agents (such as, for example, zeolites, silica gel or calcium oxide) the hot melt adhesive also acts as a barrier to water vapor which can reach the molding resin layer from the outer side through the edge seal. It is possible to produce laminated glass having more than two glass sheets by means of the hot melt adhesive according to the invention. The laminated glass produced by means of the hot melt adhesive according to the invention can be used for safety glass, acoustic insulation glass and fire protection glass.

If the hot melt adhesive according to the invention is used to produce a laminated glass, a glass sheet which is a thin film solar module, a photovoltaic module compound is obtained. It is possible to seal the edge of the sheets with the aid of the hot melt adhesive according to the invention, before the objects are molded in the interspace between the sheets of the glass sheet composite. The hot melt adhesive according to the invention can also be used, in the case of this application, to fix the objects, which are molded in the interspace between the sheets, in the interspace before filling it with molding resin. The objects that are molded right there, for example, can be lamellar systems or solar cells. An additional use of the adhesive according to the invention is one in which, when a compound is produced in which, by means of the adhesive, a glass sheet with a certain space on a protecting surface is adhered, the edge is sealed and subsequently the space between the protecting surface and the glass sheet is filled with a molding resin. In addition, the hot melt adhesive according to the invention can be advantageously used as a sealing material to feed openings for the molding resin after the interspace between the sheets has been filled with molding resin. The hot melt adhesive according to the invention, as an edge seal for laminated glass produced by means of molding resin technology has the advantage, in comparison with the known edge seals, that because of their high plastic content contribute to the reduction in stresses in the edge region of the molding resin layer which may develop as a result of the shrinkage through the polymerization during the hardening process and thus the risk of damage, as a result of the molding resin layer being detached from the glass or as a result of fractures in the molding resin layer is decreased. A further great advantage lies in the increased safety that the edge seal provides against the molding resin that is spilled during the filling and hardening process compared to known edge seals. In addition, the hot melt adhesive according to the invention makes possible; automate the application of the edge seal. Various embodiments of the hot melt adhesive that is claimed in the following examples are described in great detail. All percentages given, unless otherwise specified, are percentages by weight. Examples 1 and 2: Synthesis of poly (meta) acrylates by means of UV-polymerization. The synthesis of the hot melt adhesive precursors according to the invention are described in Examples 1 and 2. Example 1: 0.8 g (0.4% relative to the monomers) of benzyl dimethyl etal was added to 200 g of a mixture consisting of 2-ethyl hexyl acrylate, 2-ethyl hexyl methacrylate and acrylic acid (weight ratio 65: 33: 2). The mixture was placed in a compound, which consisted of a Teflon sheet and a thin sheet of polyester with a non-tacky coating (Hostaphan ex Hoechst) and which was sealed by means of an adhesive tape which was 2 mm thick and was covered on both sides with contact adhesive, and polymerized by UV radiation treatment (tube type: Philips TL 36 W / 08) for 20 minutes Example 2: 200 g of a mixture of methyl methacrylate, 2-ethyl hexyl acrylate, n-butyl acrylate, 2-ethylhexyl methacrylate and acrylic acid (weight ratio 30: 25: 20: 11: 40) were polymerized in a manner analogous to Example 1, with 2 g (1% relative to monomers) of benzyl dimethyl ketal under the influence of UV light for 30 minutes. Examples 3 to 5: Mixture of hot melt adhesive.

Example 3: In a mechanical kneader heated to 130 ° C, 80 g (66.7%) of the copolymer of Example 1 was kneaded with 40 g (33.3%) of an acrylate resin (Jágotex AP 273 ex Jáger) for 60 minutes. A vacuum was then applied for 30 minutes at 130 ° C and subsequently the material was poured into a cartridge. This hot melt adhesive contains no additional components. Example 4: 60 g (69.0%) of the copolymer of the Example 1 with 6 g (6.9%) of highly dispersed silicic acid, 20 g (23.0%) of an acrylate resin (Jágotex AP 273 ex Jáger) and 1 g (1.1% of tetrakis [methylene-3- (3, 5 -di-tert-butyl-4-hydroxyphenyl) propionate-methane) (Stabilizer Ralox 630 ex Raschig) for 60 minutes in a mechanical kneading machine heated to 130 ° C. A vacuum was then applied for 30 minutes at 130 ° C and subsequently the material was emptied into a cartridge. Example 5: 120 g (85.7%) of the copolymer of the Example 2 with 12 g (8.6%) of ac tributyl citrate (plasticizer), 1 g (0.7%) of tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate-methane) (Ralox Stabilizer 630 ex Raschig) and 7 g (5.0% silicic acid highly dispersed for 60 minutes in a mechanical mixer heated to 130 ° C. A vacuum was then applied for 30 minutes at 130 ° C and subsequently the material was emptied into a cartridge. Example 6: Use of Hot Melt Adhesive Hot melt adhesive strands of Examples 3 to 5 from a cartridge at 150 ° C were applied to the edge region of a glass sheet, having dimensions of 30 cm × 30 cm x 4 mm, by means of a heatable blow gun having a nozzle diameter of 4 mm, a second glass sheet having the same dimensions as the first one was placed on top to be level with each other , and this was pressed to give an interspace between the sheets of 2 mm Immediately afterwards an acrylate-based molding resin (Naftolan® UV 22 ex Chemetall) was emptied through a feed opening leaving the edge seal free by means of a feed hose and the opening was sealed by means of a hot melt adhesive. The filled sheets were hardened by UV-radiation treatment (tube type: Philips TL 36 W / 08) within 15 minutes.

Example 7: Spreading times of the uncured molding resin in the glass sheet compounds containing the hot melt adhesive according to the invention.

- In order to demonstrate the advantage of the high level of safagainst spillage that is achieved when the hot melt adhesive according to the invention is used, in comparison with the edge seals that were previously used, the spill times of a Unhardened molding resin were determined in straight glass sheet compounds having different edge seals in each case. The spill time is the time during which the edge seal is infiltrated by the molding resin and the molding resin starts to spill. The results are shown in Table 1 Comparative Example A: Use of a butyl cord as an edge seal. A commercially available butyl cord having a core having a diameter of 3.5 mm (Naftotherm® Bu-cord 4554 ex Chemetall) was applied to the edge reagent of a glass sheet in a manner analogous to Example 6, a second Glass sheet was placed on the top in order to be level with each other, and this was pressed to give an interspace between the sheets of 2 mm. Immediately afterwards, an acrylate-based molding resin was emptied and, in a manner analogous to Example 7, the spillage time of the uncured molding resin was determined. The results are shown in Table 1.

Comparative Example B: Use of a self-adhesive, solid polyacrylate-based adhesive tape as an edge seal. A commercially available self-adhesive was applied, solid polyacrylate-based adhesive tape (Acrylic foam tape® 4918 ex 3M) having a thickness of 2 mm, to the edge region of the glass sheet in a manner analogous to Example 6, a second sheet of glass was placed over the upper part in order to be level with each other, and this was pressed on the adhesive tape. Immediately afterwards, an acrylate-based molding resin was emptied and, in a manner analogous to Example 7, the spillage time of the uncured molding resin was determined. The results are shown in Table 1.

Comparative Example C: Use of polyacrylate-based foam tape, which is covered on both sides with a contact adhesive, such as an edge seal. A commercially available polyacrylate-based foam tape coated on both sides with a contact adhesive (Acrylic foam tape® 4912 ex 3M) and having a thickness of 2mm was applied to the edge region of a glass sheet in a manner analogous to Example 6, a second sheet of glass was placed on the top so as to be level with one another, and this was pressed onto the adhesive tape. Immediately afterwards, an acrylate-based molding resin was emptied and, in a manner analogous to Example 7, the spillage time of the uncured molding resin was determined. The results are shown in Table 1. Table 1: (Spill times of glass sheet compounds with different edge seals after filling with acrylate-based molding resin and without hardening the molding resin It is noted that the spill times of Comparative Examples A to C are clearly below the spill times of Examples 3 to 5. This shows that the sheet compounds produced with the hot melt adhesive according to the invention achieve a comparatively high level of production-safety, since the infiltration of the edge seal by the molding re-sine and the resulting leaks do not need to be considered.

Claims (8)

1. CLAIMS 1. the hot melt adhesive for sealing the edge of laminated glass that is produced by means of molding resin technology, characterized in that the hot melt adhesive consists of; homopolymers or copolymers of acrylates or methacrylates or mixtures of the polymers.
2. 2. The hot melt adhesive for sealing the edge of laminated glass produced by molding resin technology, characterized in that the hot melt adhesive contains homopolymers or copolymers of acrylates or methacrylates or mixtures of the polymers and additional components according to the following composition (specified in percentage by weight): homopolymers or copolymers of acrylates or methacrylates or mixture of polymers 30 - 100% thermoplastic polymers 0 - 50% natural and synthetic rubbers 0 - 50% viscosity additives 0 - 30% plasticizers 0 - 50% adhesion promoters 0 - 5% stabilizers 0 - 5% reinforcement loads and non-reinforcement 0 - 50% 3.
3. The hot melt adhesive according to claim 2, characterized in that; the hot melt adhesive contains homopolymers or copolymers of acrylates or methacrylates or mixtures of the polymers and additional components according to the following preferred composition (specified in percent by weight): homopolymers or copolymers of acrylates or methacrylates or mixture of polymers 50 - 100% thermoplastic polymers 0 - 30% natural and synthetic rubbers 0 - 30% viscosity additives 0 - 25% plasticizers 0 - 30% adhesion promoters 0 - 2% stabilizers 0-2% reinforcement loads and non-reinforcement 0-30% 4.
4. The method for preparing the hot melt adhesive according to claims 1 to 3, characterized in that the components are mixed by means of a mechanical kneader, or a single screw extruder or a twin screw extruder, a planetary dissolver, a blade mixer with a dissolving disk, or turbulence mixer, and the mixing temperature is in the range of 40 to 200 ° C, preferably in the range of 70 ° to 180 ° C.
5. The method according to claim 4, characterized in that the components are mixed under vacuum or in a protective gas.
6. 6. The use of the hot melt adhesive according to claims 1 to 3 for the production of laminated glass for safety, sound insulation, and fire protection purposes, for the production of photovoltaic modules and also for the production of glass laminated with molding objects in the interspace.
7. The use according to claim 6, wherein the hot melt adhesive is applied to the edge region of a glass sheet, a second sheet of glass is then placed on it in order to be congruent with the The glass sheet composite is then pressed to a certain thickness, the interspace between the sheets is then filled with a molding resin, the feed opening is then sealed, and finally the molding resin can be cured.
8. 8. The use of the hot melt adhesive according to claims 1 to 3, as a sealing material for a feed opening for the molding resin.