DE2151648A1 - Lamination of sheet materials - using olefinic pre-polymers as adhesives and hardening by ionising radiation - Google Patents

Abstract

Materials which form active centres on irradiation, are combined by using an intermediate layer of a resin material which can be hardened by exposure to ionising radiation. A hard adherent surface coating can be formed on the outside of the laminate at the same time, using a resin layer which is also hardened by radiation. Pref. an electron beam with energy of 0.1-3 MeV is used, with a dosage of 0.1-5 Mrad. The resin is pref. an acrylic resin prepolymer contg. reactive double bonds in an organic solvent and/or vinyl monomer such as styrene or methyl methacrylate. Suitable materials for laminating are wood, natural cellulose fibres and plastics. Strong, durable adhesion is obtained in a few seconds without heating or generation of harmful vapours such as formaldehyde. Laminates are dimensionally stable and resistant to water and weathering.

Description

Method of joining sheet materials The invention relates to an improved method of joining two or more sheet materials or plates.

For bonding flat materials made of wood, plastics, paper, It is customary to place an adhesive between the two-dimensional fabric and the like to be connected Insert materials and the adhesive under the action of heat, pressure and / or to dry or cure in the presence of a catalyst. The glued products or laminates are suitable for a wide variety of applications, e.g. as building materials or construction materials for interiors and in the price range. With these materials There must be no delamination or splitting, even if it lasts for a long time can be used. They must also have a high level of water and weather resistance to have. However, these conditions apply to the bonded products or laminates, which are produced in the manner described above are not sufficient Fulfills.

The usual bonding methods usually use a formaldehyde condensation resin, e.g. a urea resin, melamine resin or phenolic resin is used. These resins to develop however, during handling and use for making the bond Formaldehyde, which is harmful to human health. Furthermore, will also during the use of these laminated products, especially indoors, the free formaldehyde remaining in the adhesive is gradually released and has a detrimental effect on human health.

The usual lamination process has the further disadvantage that to achieve a quick bond generally requires heat. When the lamination is done at room temperature or normal temperature, this is excessive long time required, the invention has for its object to provide an improved To make lamination process available, in which durable bonds without loosening the Adhesive connection or splitting even with long service life and excellent Dimensional accuracy and water and weather resistance of the bond is achieved, no harmful Substances are released both during and after the lamination of the components is achieved in a very short time without the need for heat and lamination and surface lamination are possible at the same time.

In the method according to the invention, two or more two-dimensional Materials or plates that are active when exposed to ionizing radiation Able to form, bonded or laminated by using a resin material that passes through Exposure to ionizing radiation can be cured between those to be joined Components inserted and the multilayer material to harden the resin with ionizing radiation is irradiated.

When a coating material containing a resin material that by Exposure to ionizing radiation can be cured on the top of the not yet laminated Composite material is applied, a Covering can be formed at the same time as the sheets or panels are glued.

According to the invention, flat materials, plates or the like are laminated, capable of forming active sites when exposed to ionizing radiation will.

Examples of such materials are wood and natural cellulose fibers and plastics (e.g. polyethylene resins, polypropylene resins, polystyrene resins, polybutadiene resins, Diallyl phthalate resins and ABS resins). These materials are in the form of leaves or plates, e.g. in the form of paper-like sheets or webs, fabrics or Fabrics used.

According to the invention, two or more different or similar flat materials or panels can be connected at the same time.

In the lamination process according to the invention, a resin material, that can be cured by exposure to ionizing radiation, between the adjacent flat materials (or panels) to be connected are inserted. Prepolymers or prepolymers containing olefinic double bonds are suitable as resins contained in the molecule.

If the prepolymer is in liquid form, it can be used as such be applied. However, this prepolymer is preferably mixed with a suitable one Amount of an organic solvent and / or a vinyl monomer that is reactive Contains double bonds in the molecule, diluted in order to apply to the flat materials or plates to facilitate.

All 11 prepolymers ", the olefinic double bonds, are suitable (preferably about 0.5 to 3 average per average molecular weight of 10wo) contained in the molecule, and hardened by exposure to ionizing radiation or can be networked. The double bonds can be in the chain of the prepolymer or side constantly on the prepolymer chain or at the ends of the Prepolymer chain be present. As examples of prepolymers, the olefinic If the polymer chain contains double bonds, they are different unsaturated ones To name polyester precondensates (prepolymers). Examples of prepolymers with Double bonds that are pendent on the polymer chain are the alkyd hearts, Allylic resins, diene hearts, modified acrylic resins and modified epoxy resins. Examples of prepolymers with terminal olefinic double bonds are the modified ones Polyester resin, modified urethane resin and modified polyamide resin.

These prepolymers can be used at normal temperature or room temperature solid or highly viscous and as such are difficult to apply to the surface can be applied from flat materials or panels. To facilitate the The prepolymers are preferably applied using an organic solvent and / or with a vinyl monomer that has reactive double bonds in the molecule contains, diluted. Prepolymers that have a very high molecular weight and are used in cannot be dissolved in such an organic solvent or vinyl monomer can, therefore, are out of the question for the purposes of the invention.

Preferably the prepolymer is only diluted with a vinyl monomer. Suitable as "vinyl monomers" are liquid monomeric vinyl compounds that are reactive Contain double bonds in the molecule and when exposed to ionizing radiation able to react, examples of such vinyl monomers are acrylic acid, methyl acrylate, Ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, Propyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, Dode- cyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, Styrene, a-methylstyrene, vinyltoluene, dichlorostyrene, methyl vinyl ketone, acrylonitrile, Diacetone acrylamide, diallyl phthalate, divinylbenzene and triallyl isocyanurate. Of these Particularly preferred compounds are styrene and methyl methacrylate.

The amount of this vinyl compound is to be chosen so that a liquid Resin material can be formed having a viscosity such that it can be handled and can be applied. However, when an excessively large amount of the vinyl monomer is used, the reactivity for curing the resin material becomes excessive greatly reduced. Generally about 30 to 60 parts by weight of vinyl monomer will be used used per 100 parts by weight of prepolymer.

When an excessively large amount of a vinyl monomer is required is to use the prepolymer to produce a liquid resin material suitable for application To dilute, the vinyl monomer can be partially replaced by an organic solvent be replaced. It is also possible to use the prepolymer only with an organic solvent to dilute. However, this organic solvent must be removed at the end, so that its amount should be as small as possible. Generally it will be in a Amount of 0 to 15 wt., Based on the prepolymer, used.

For the purposes of the invention, organic solvents are used, which are miscible with the prepolymer and the vinyl monomer. To be favoured for example ketones, e.g. acetone and methyl ethyl ketone, aromatic hydrocarbons, e.g. benzene, toluene and xylene, and alcohols, e.g. methyl alcohol and butyl alcohol0 The viscous liquid resinous adhesive (i.e. that with a vinyl monomer and / or organic solvents thin prepolymers) is applied to the surface a flat component (or plate) applied to another flat Component (or plate) is to be glued, whereupon the components are placed on top of each other will.

The application of the liquid resin material can be any suitable Manner, e.g. with a brush coating machine, by spray application, with a blanket coater, a roller coater and by dipping die The amount of resin material to be applied is not critically important as long as it is can be cured by exposure to ionizing radiation. The amount can depend on the particular prepolymer, the type and thickness of the to be bonded flat components or plates, etc. can be varied. In general, however the resin adhesive applied in an amount of about 300 g / m or less.

One of the important features of the invention is that, if desired to have a cured coating on top of the laminate simultaneously the lamination can be formed. When the formation of such an external therzug is desired, a liquid paint or coating compound applied. Serving as the coating mass previously described v skoser liquid resin adhesive, which pigments, dyes or other additives usually applied to improve the properties of aes Films can be used, can be added. These additives are in the Industry Qer paints and varnishes well known. These paints and coatings can be applied in the same way as in the previous connection with the appearance of the resin adhesive was described. The outside overrug came in one Thickness of about 1 mm or less can be applied.

According to the invention, the not yet laminated composite material with the hardenable @@@@ ch @@@@ zw @ s @@ den neighboring components or plates and, if necessary, with the outer coating layer, then the action exposed to ionizing radiation. The sounding S @ @@ ung are suitable for the Purposes of the invention generated by an accelerator electric @ @st @en, neutron beams, heavy proton rays, pron rays.

Gamma rays, beta rays, alpha rays caused by radioactive Materials are generated, x-rays, etc. In general, however, the use is of electrons with an energy of 0.1 to 3 MeV from a value point of view preferable.

The amount of radiation that is to be absorbed by the laminate is not critical important as long as the sheet-like material forming the laminate does not adversely change or damaged and the resin material is cured properly. The amount of radiation may depending on the reactivity of the resin material and the amount nd type of vinyl monomer used can be varied.

In general, however, the amount of radiation is about 0.1 to 5 Mrad.

During this irradiation, active sites are formed in the material, from which the flat materials or panels to be connected are made. Similar active sites are also formed in the resinous adhesive material. Hence, by mutual Reaction (e.g. graft copolymerization) between the active sites in the one to be connected Material and the active sites in the resin material form a strong chemical bond educated. At the same time, the prepolymer and the vinyl monomer act in the resin material Hardening or crosslinking reactions as a result of irradiation. As a result of these different chemical reactions create a strong, durable bond. These reactions are Finished in a few seconds without the need for heat or catalysts If a coating is applied to the top of the laminate, find the same Reactions take place, being a clingy one and cured coating film The invention has the following advantages over, for example the usual lamination process: 1) No gases or substances are evolved or free that are detrimental to human health0 2) A strong, firm and durable bonding is achieved within a few seconds without exposure to heat0 3) Because the bond is the result of chemical reactions between the resin material and the flat components or plates to be connected and chemical reactions of the resin material itself, it is very strong and the laminate is dimensional stable and highly resistant to water, hot water and weather.

4) Since the bonding takes place in an extremely short time without Heat is required, the bonding of large-area hard planar materials or plates can be done in a simple manner and even continuously.

5) More than two flat materials or panels can be used at the same time be connected to each other.

6) If desired, a firmly adhesive can be used at the same time as gluing Outer coating are formed 0 Example 1 A mixture of 228 g (0.7 mol) of fumaric acid, 124 g (0.3 mol) of phthalic anhydride and 234 g (1.1 mol) of propylene glycol was in Put a flask equipped with a stirrer, thermometer, water separator and nitrogen inlet pipe was provided. The mixture was heated to 150 ° C in one hour while Nitrogen gas was introduced.

The system was held at 150OC for 1 hour and then for 2 hours heated to 2000C. As the reaction proceeded, water was formed as a by-product. This water was collected in the water separator. After the material 5 hours was maintained at 200 ° C, the heating was stopped and the system was turned on Chilled 1000C, whereupon 0.05 g of hydroquinone and 306 g of styrene were added and that Mixture was stirred to form a resin adhesive.

The surface of a panel made of lava wood (thickness 2 mm) was covered with the Resin material prepared in the manner described above based on the unsaturated Polyester coated in an amount of about 250 g / m2. Another board from Lavan wood of the same thickness was put on top, and the whole thing was done with electron beams Treated under the following conditions: voltage 1.5 MeV current 150 linear Speed 1.31 cm / second Distance between the radiation source and the surface of the laminate about 10 cm number of passages 5 amount of radiation 5 Mrad Example 2 In a flask equipped with a stirrer, thermometer and reflux condenser, were Added 200 g of xylene, which was heated to 130 to 1400C. Then it became a mixture of 65 g (35 mol) methyl methacrylate, 83 g (45 mol%) ethyl acrylate, 52 g (20 mol-ß) Glycidyl methacrylate and 3 g of tert-butyl perbenzoate were added dropwise over the course of 2 hours. The mixture was held at 130-14000 for about 3 hours and then cooled to 1000C. Then 26 g of acrylic acid, 1 g of triethylamine and 0.04 g of hydroquinone were added. The mixture was held at about 11,000. After «reaching an acid number of about 30 the xylene was distilled off under reduced pressure, on what 94 g of butyl acrylate was added, whereby a uniform solution was obtained (Adhesive based on acrylic resin).

Using the liquid resin material thus prepared A laminate of lava wood panels was produced in the manner described in Example 1 The laminates produced according to Examples 1 and 2 were subjected to the dip splitting test subjected and tested for resistance to boiling water. The results are listed in the table below.

Sample Example 1 Example 2 Commercially available laminate * Auspalt- None Splitting no splitting test ** on the bond Defor- No deformation No deformation. after 2000 hours after 2000 hours splitting perfect the perfect against free 20C hours boiling water * Two layers of lava wood (thickness 2 mm each), with adhesive on the base glued by phenol-formaldehyde resin.

** Immersed in boiling water for 4 hours, then in the air for 20 hours dried at 60 + 30C and then immersed in boiling water for 4 hours and then dried at room temperature.

Example 3 2 layers of lava wood (thickness 3 mm each) and a patterned one Sheets of paper for decorative laminates were laid one on top of the other, according to Example 2 produced acrylic resin material in an amount of about 250 g / m2 between the neighboring wood layers. The multilayer material was based on the in Example 1 described way treated with electron beams to the two wood layers and the DeRorat4cngboaen applied to the surface within to stick in a few seconds. The decorative plate obtained was excellent in terms of strength of the glue, wet strength and dimensional accuracy.

Example 4 A coating composition (paint) was made from 15 g of titanium dioxide, 85 g of the acrylic resin prepolymer prepared according to Example 2 and 100 g of glass beads manufactured. The mixture of these three materials was placed in a pressure-resistant glass bottle (Volume 250 ml) given. The bottle was placed on a shaker and shaken for about 1 hour. The even mixture was withdrawn from the bottle and filtered to obtain a paint.

Two layers of lava wood (3 mm thick) were placed one on top of the other. The acrylic resin material produced according to Example 2 was located between the layers in an amount of 250 g / m2. A thin film was put on top of the laminate (Thickness as above) of the paint prepared in the manner described above is applied. The whole was irradiated in the manner described in Example 1 under nitrogen. Within a few seconds, the layers of lava wood were firmly glued together. Simultaneously an adherent film had formed on the surface. The received decorative plate had excellent properties in terms of adhesive durability, wet strength and dimensional accuracy.

Example 5 Three layers of lava wood (thickness 2 mm each) were placed one on top of the other. Between the adjacent layers there was a thin layer (approx. 250 g / m2) of the according to Example 1 produced resin material based on the unsaturated polyester prepolymer The whole was irradiated in the manner described in Example 1, whereby a laminate was obtained which had excellent properties like that according to Example 1 produced laminate had.

Example 6 The surface of a lava wood panel (thickness 6 mm) was with the resin material prepared according to Example 2 based on the acrylic resin prepolymer coated in an amount of about 100 g / m². A cotton fabric was placed on top of this layer placed. The whole was irradiated in the manner described in Example 1, wherein a laminate made from the lava wood panel and the cotton fabric firmly attached to it was obtained.

Example 7 Two sheets of hard polyethylene (3 mm thick) were made Laying on top of each other. Between the plates there was a thin layer of the according to Example 2 produced resin material based on the acrylic resin prepolymer (approx 300 g / m2). The whole was irradiated in the manner described in 'Example 1, wherein an excellent laminate was obtained, the bonds of which did not come off0 Example 8 Two lava wood panels (thickness 2 mm each) and a plate made of hard polystyrene (Thickness 2 mm) were placed one on top of the other in the order given. Between adjacent layers was a layer of resin material based on an unsaturated Polyester (approx. 300 g / m2).

The whole was irradiated in the manner described in Example 1, whereby a laminate with firmly bonded layers was obtained.

Claims (9)

Pate ntans r1ich e 1) Method of joining two or more sheet materials or plates that form active sites when exposed to ionizing radiation able, characterized in that the flat materials or plates with one inserted between the adjacent layers, by the action of ionizing Radiation curable resin material superimposed and then the superimposed Treated layers with ionizing radiation and thereby harden the resin material. 2) Method according to claim 1, characterized in that one is on the top of the superimposed layers a coating mass before irradiation based on resin, which is curable by treatment with ionizing radiation is, and by the irradiation a firmly adhering and hardened film on the Surface of the laminate forms at the same time as the firm gluing of the layers. 3) Method according to claim 1 or 2, characterized in that with ionizing radiation with an energy of about 0.1 to 3 MeV is used. 4) Method according to claim 1 or 2, characterized in that the Radiation is delivered in a total dose of about 0.1 to 5 Mrads. 5) Method according to claim 1 or 2, characterized in that electron beams can be used as ionizing radiation. 6) Method according to claim 1 to 5, characterized in that as Resin material an unsaturated polyester resin prepolymer is used. 7) Method according to claim 1 to 5, characterized in that as Resin material an acrylic resin prepolymer with reactive double bonds is used becomes0 8) Method according to claim 1 to 7, characterized in that the prepolymer in an organic solvent and / or a vinyl monomer, the reactive Contains double bonds in the molecule, is dissolved. 9) Method according to claim 1 to 8, characterized in that styrene or methyl methacrylate is used as the vinyl monomer.