JPH0379362B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to aqueous compositions and methods of using the aqueous compositions. Although the compositions and methods of the present invention were initially developed for inks and related printing processes, it has been found that they are equally effective in other coating and bonding environments. be. The most commonly used coatings and binders these days are made of compositions which form a film or lattice upon evaporation of the carrier. These compositions generally contain inert, dispersed solids or soluble materials with the desired properties, which are obtained upon evaporation of the carrier.
Especially in printing applications, these properties (i.e., film hardness, gloss, tack) must be achieved quickly as the substrate must pass through the printing press at high speeds. No. Energy consumption is therefore prohibitive and ``quickly volatile'' organic solvents are used, creating fire hazards and pollution problems. The use of water-based inks instead of solvent-based products is not new in itself. Conventionally, this type of water-based ink has been used in the form of a dispersed polymer. Water-based inks save money, eliminate fire hazards, reduce air pollution, and do not use any hydrocarbons (hydrocarbons are prone to supply shortages and subsequent price increases). Although they have many advantages over solvent-based inks, they also have drawbacks such as pigment dispersion, gloss, film thickness, curing time, and flow characteristics. It was hot. These difficulties have made water-based inks using dispersed polymers unattractive. Against this background, the main object of the present invention is to eliminate the disadvantages always found in water-based inks in the prior art mentioned above (rather than to reproduce the drawbacks seen in solvent-based inks), Moreover, the object is to provide a water-based ink that is inexpensive, easy to use, and non-toxic. It is also an object to provide separate aqueous coating and bonding compositions which have been developed by our research and which are superior to such compositions of the prior art. and () are found to be within the scope of the inventive concept. These will be detailed next. Broadly speaking, the present invention can be summarized as follows: dyes;
A composition comprising a pigment or an auxiliary film-forming material for producing a clean coating, and an aqueous monomer system, the aqueous monomer system comprising at least one water-soluble or water-miscible or water-dispersible monomer. the composition is suitable for application to a substrate and is heated by UV radiation or by electron beam radiation in the presence of the photoinitiator catalyst; The present invention provides a polymerizable aqueous coating composition that does not require air drying and is characterized in that it is curable in the absence of. In the system described, the monomers used are very economical carriers, ie reactive monomers which are soluble in water. The water carrier imparts free flowing properties to the composition. This water carrier does not need to be removed by evaporation for the composition to achieve its desired properties. The composition is cured to a solid polymer by applying radiation, leaving the carrier (or proportions of the carrier) intact. The radiation can be of any type capable of initiating and continuing polymerization (e.g., heat, UV,
IR, electron beam, gamma and other radiation). The present invention also provides a method of coating onto a suitable substrate. The method generally involves applying the polymerizable aqueous coating composition described above onto the substrate, reacting with a hydrophobic polymer (e.g., rapidly absorbing and/or evaporating water present into the substrate). It consists of the process of forming Additionally, the present invention provides a bonding or foaming method. This involves the step of mixing the aqueous monomer system described above with the appropriate main components and optionally further catalyst and curing the resulting system/component mixture as described above. By controlling the rate of water release as well as the ultimate amount of water, the flexibility of the resulting film can be controlled. Although the present invention will be described with respect to the preferred embodiments of the invention set forth above, it should be understood that all specific descriptions thereof are merely illustrative of the invention and are therefore not intended to be limiting. You should understand. When coating, a low viscosity composition containing an aqueous monomer system and suitable coating components (e.g. pigments, dyes, etc.) will always contain the catalysts mentioned above to accelerate curing, and It may also contain one or more of the above-mentioned non-reactive water-floating components (emulsions, dispersed or dissolved resins, polymers, etc.). The composition is generally formulated taking into account factors such as the type of coating required and the type of radiation used. For example, if curing is carried out by electron beam radiation, no catalyst is required. For bonding and foaming, the aqueous monomer system is optionally used in combination with fillers, plasticizers, catalysts and blowing agents (one or more of each). The filler is selected from those described below. In this case, it is a dispersion of solids in a fluid fluid, and the composition is characterized by being cured by radiation or (for example) by a free-radical-generating catalyst. A particularly preferred aqueous monomer system is a one-component monomer system. However, it is also possible to use binary or ternary monomer systems. These will be explained in more detail below. Water soluble or miscible with water (or dispersible in water)
The monomers may be selected from any conventionally used monomers. Examples of such monomers include acrylic acid, methacrylic acid and their derivatives;
- Methylolacrylamide derivatives; modified acrylamides, especially acrylamides modified with aldehydes etc. to ultimately produce polycondensation type polymers; and pyrrolidones such as vinylpyrrolidones, and mixtures thereof. The catalyst (described above) is generally a conventional free radical generating moiety selected according to the type of radiation (thermal, UV, etc.) or other method of curing used. Both of these start a reaction,
and/or for the purpose of promoting. Catalysts include (for example) UV photoinitiators or free radical generating catalysts (alone or as a redox pair), and specific examples include sodium bisulfite, sodium formaldehyde sulfoxylate, and zinc formaldehyde sulfoxylate. Mention may be made of persulfates (eg ammonium persulfate), peroxides, AZDN, as well as various reducing agents such as. Benzyl dimethyl ketal, known as "IRGACURE 651" (registered trademark of Ciba Geigy), is a typical compound suitable for promoting UV radiation. No catalyst is required if curing is carried out by electron beam. The catalyst can be added at the same time as the monomer. It may also be added later together with any other conventional additives (such as fillers) or the composition may be pre-applied to the substrate to which it is subsequently applied. . As the plasticizer that functions to improve the flexibility of the cured composition, a humectant is preferably used. Typical examples are calcium and zinc chloride, sugar, glycerin and glycols, as well as other synthetics such as starch and starch derivatives, polyvinyl alcohol, gums and modified cellulose. The non-reactive water-floating components mentioned above, such as emulsions, dispersed or dissolved resins, or polymers, do not participate in the polymerization reaction. However, it is easily dispersed or dissolved in the composition and has the function of improving the final properties. Oxygen suppression becomes a real problem in applications as printing inks with very low coating weights. One optional form of the invention overcomes this problem by adding nitrogen externally to the printed substrate. Alternatively to this method, chemicals can be added to the system that generate carbon dioxide or nitrogen in situ during polymerization. At this time, the chemicals may include, for example, potentially
There are alkalis (e.g. basic carbonates for acidic formulations) that produce _CO2 . In binary monomer systems, acids such as hydrochloric acid and basic carbonates (e.g. sodium bicarbonate or ammonium carbonate) are used.
Base reactants can be used. In one-component monomer systems only basic carbonates can be used. This monomer system becomes acidic during the reaction and therefore subsequently reacts with the alkali carbonate and finally
Produces _CO2 . The monomer system is expanded to a three-component system, where the first component is a water-soluble or water-miscible (or water-dispersible) monomer component, and the second component is a plasticizer (e.g. The third component may consist of a plasticizer, a _CO2 -containing alkali, and a reducing redox couple. These three components can be mixed, and when mixed, foaming and polymerization occur. Binary monomer systems include water-soluble or water-miscible (or water-dispersible) monomers, plasticizers (e.g. carbohydrate plasticizers), CO2 _- containing alkalis and UV
It may have a first component comprising a catalyst and a second component comprising a carbohydrate plasticizer solution and an acid (these components may alternatively be in other configurations as shown in the Examples below). ). When these components are combined and cured (e.g., by exposure to UV light), polymerization occurs with the production of _CO2 gas. The gas thus produced foams and oxygen is displaced. In two-component and three-component systems, foaming begins as soon as the components are combined, but the polymerization reaction takes longer. The CO ₂ bubbles formed are therefore released prematurely. Such systems are therefore less suitable for use as printing (or other) thin films than the one-component monomer systems that are particularly preferred therefor. Such a one-component monomer system consists of a water-soluble or water-miscible (or water-dispersible) monomer, a potentially _CO2- forming alkali, a plasticizer consisting of a humectant, and a UV catalyst. be able to. Exposure to a UV light source initiates polymerization, creating an acidic environment that in turn reacts with alkali to produce CO ₂ . Polymerization occurs before gas generation begins, and the resulting gas is engulfed in a viscous polymer slime. As mentioned above, the coating component may be a dye or pigment. This includes water-soluble dyes, aqueous pigment dispersions, and materials such as clay (eg, highland clay) and white clay. Other additives are also optionally added, namely surfactants (to improve dispersion), plasticizers (as described above) and viscosity control agents. Among those specifically mentioned above, a particularly preferred water-soluble or water-dispersible monomer is acrylamide or its N-methylol derivative. The conventional method of producing acrylamide is to hydrate acrylonitrile at 100°C in the presence of sulfuric acid and water to produce sulfuric acid acrylamide;
The sulfate is then removed to obtain pure acrylamide. In the present invention, acrylamide is produced by reacting acrylonitrile in the presence of hydrochloric acid to produce acrylamide chloride. Further addition of calcium hydroxide produces calcium chloride. Production of calcium chloride in this manner is a convenient and inexpensive means of eliminating by-products that would otherwise be a nuisance. Acrylamide monomers are suitable as such (without further modification) as water-soluble or dispersible monomers. However, if acrylamide is modified to its N-methylol derivative, the range of formulation flexibility becomes even wider. When acrylamide is reacted with various aldehydes, corresponding methylol derivatives are produced, and when these are then polymerized, a condensation reaction also occurs at the same time. Formaldehyde (in the form of paraformaldehyde) is a particularly preferred reactant. The solids content is not particularly important. Returning now to the other (non-ink) aqueous compositions already mentioned above, all the problems of the prior art have once again been solved. Thus, in the field of paper and cardboard sizing, the main problem encountered when using prior art acrylamide emulsions is the difficulty in removing the residual carrier, which requires a great deal of energy during the drying operation. It was necessary. This problem is solved with the present invention. That is, when the compositions of the present invention are used as alternative coating compositions, such compositions can be applied to substrates using conventional techniques and cured by the methods described above. .
Typical substrates include paper, cardboard, wood, metalwork, glass, and woven synthetic surfaces. When the invention is applied to bonding, the composition will contain a conventional solid carrier (filler) as the main component. Solid carriers may include (ground) natural minerals such as clay, talc, slag, china clay, quartz, diatomaceous earth, etc., and (ground) synthetic minerals such as alumina, silicates, etc. Furthermore, natural rocks (crushed and separated) such as marble, calcite, pumice, etc., as well as solid synthetic polymers (e.g. polyethylene), (particles of) organic materials such as sawdust and plant fibers, and paper pulp, etc. Organic pulps such as For such solid carriers, water-soluble or water-miscible (or water-dispersible) monomers serve as binders. In one such embodiment of the invention, methylol acrylamide together with a thermally induced free radical catalyst acts as a binder for sand and/or marble debris.
When formed into the desired shape and cured by heat, e.g. in a hot plate press, heated roller, dielectric furnace, etc., such compositions undergo a polycondensation type reaction to form a hard, dimensionally stable replica. Form a brick. Sawdust and/or paper may be used in place of the sand, marble and marble chips, and the resulting composition is cured by the methods described above. In the above case, the advantage of this method is that a large amount of energy can be saved due to the exothermic polymerization reaction. The above carrier(s) can of course be multiplied. That is, one or more of plasticizers, stabilizers, dyes, etc. can also be added. When the invention is applied to foaming, the composition is made based on water-soluble monomers, plasticizer(s) and blowing agent(s).
The water-soluble monomers may also be in the form of binary monomer systems (containing monomers, plasticizers, catalysts, etc.) as shown in the composition above or as specifically exemplified in the examples below. good. Alternatively, the first component is a monomer, the second component is a mixture of a plasticizer, an acid and a free radical catalyst, and the third component is a combination of a plasticizer, a CO ₂ -containing alkali and a reducing redox. It may be a three-component system consisting of a mixture of the following. The components can be formulated and mixed to equal volumes. Foaming and polymerization occur simultaneously with mixing. The foamed compositions produced in this way, in which air acts as a filler, have use, inter alia, in thermally insulating environments and as protective coverings for animals. Further details of the invention will now be described with reference to specific embodiments. These examples are illustrative of all aspects of the invention. All parts are parts by weight unless otherwise specified. In carrying out the Examples, when compositions that have been manufactured and sold exclusively are used, they are available in the art under trade names or similar names, and can usually be identified, so they should be identified in that way. ,
Furthermore, in connection with this, we decided to identify them by referring to their general chemical structures as much as possible. Similarly, if known commercial equipment is used (such as a radiation source in a particular example), such equipment is identified by methods known in the art. Example 1 This example illustrates a ternary monomer system. The first component consists of 100 parts by weight of N-methylolacrylamide (60%) (hereinafter often abbreviated as NMA for convenience). The second component was made up of 50 parts water, 45 parts sugar, 3.5 parts hydrochloric acid and 1.5 parts ammonium persulfate, and the third part was 50 parts water, 45 parts sugar, 1.5 parts by weight. 3.5 parts of formaldehyde sodium sulfoxylate and 3.5 parts
Made from parts by weight of sodium bicarbonate. These three components were mixed in equal amounts. Example 2 This example illustrates a two-component monomer system. The first component is 37.5 parts by weight of water, 52 parts by weight of calcium chloride, 2 parts by weight of hydrochloric acid, 8 parts by weight of acetone co-solvent, and 0.5 parts by weight of a catalyst known as "Irgaquiure 651" (supra). was made by mixing. The second component was made from 87 parts by weight of 60% NMA, 5 parts by weight of ammonium hydroxide, and 8 parts by weight of ammonium carbonate. The two components were mixed. Example 3 This example illustrates a two-component monomer system. The first component was made by mixing 66 parts by weight of 60% NMA, 28 parts by weight of 50% sugar/water solution, 0.3 parts by weight of "Irgakiure 651" and 5.7 parts by weight of sodium bicarbonate. The second component was made by mixing 90 parts by weight of a 50% sugar/water solution, 9 parts by weight of acetone, 0.3 parts by weight of Irgakiure 651 and 0.7 parts by weight of acetic acid. The two components were then mixed. Examples 4-7 These examples each illustrate a separate one-component monomer system. For convenience, these systems are presented in a table.

[Fusion Systems Corp.'s U.V. curing device (H-type valve)]

Example 9 Flexo printing ink (black) on recycled paper: UV
Radiation cured Composition: 60% N-methylolacrylamide (water-soluble monomer) 50.0 PVPK-30 (viscosity control agent) 0.5 Alkanate 3SN5 (surfactant) 0.05 CONTINEX N326 (carbon black pigment) 7.45 Water 40.0 IRGAKIURE 651 (photopolymerization initiator catalyst) 2.0 NM PVPK-30 (polyvinylpyrrolidone)
A. Dissolve in solution and then add surfactant and water to it. The pigment and photoinitiator catalyst are dispersed in the same manner as in Example 8. Printing on paper substrates is done using a flexo printing machine. UV curing is carried out as in Example 8. Example 10 Transparent coating of printed paper: Cured with UV radiation Composition: 60% N-methylolacrylamide (water-soluble monomer) 30.0 PRIMAL HA-16 (polymer emulsion) 30.0 Irgaquia 651 (photopolymerized) Initiator Catalyst) 1.0 Acetone 5.0 Water 34.0 Stir the polymer emulsion into the NMA solution to mix and add water. The photopolymerization initiator catalyst is dissolved in acetone, and the catalyst solution is gradually added to and mixed with the NMA solution using high-speed mixing. Coating is performed using a roll coater equipped with a doctor blade.
Radiation is performed in the same manner as in Examples 8 and 9. Example 11 Transparent coating of clay-coated paper: cured by electron beam radiation Composition: 60% N-methylol acrylamide (water-soluble monomer) 50.0 33% Platamide M1255 (water-soluble copolyamide resin)
48.0 Eriosin Blue Dye 2.0 Mix the polyamide and NMA solution and dissolve the dye therein. Coating is carried out as in Example 10. Electron beam radiation is performed using a 250KV electron accelerator. Example 12 Clay coating on paper: cured with UV radiation Composition: 60% N-methylol acrylamide (water-soluble monomer) 48.0 Etsucalite clay 50.0 Irgakyure 651 2.0 Photoinitiator catalyst in NMA solution using bead or sand mill disperse. Then, disperse the clay in the same way. The coating is Example 10 and
Proceed as in step 11 (alternatively, an air knife may be used instead of the doctor blade). UV radiation is the same as in Examples 8-10. Example 13 Glazing ceramic tiles: cured by UV radiation Composition: 60% N-methylol acrylamide (water-soluble monomer) 35.0 Powdered red glazing glass (pigment) 40.0 Sandray 1000 (photopolymerization initiator catalyst) 1.0 Acetone 4.0 Water 10.0 Dilute the NMA solution with water and dissolve the photoinitiator catalyst in acetone. Next, add the former to the latter and mix vigorously. Disperse the glazing glass powder into the resulting mixture (while continuing to mix vigorously). Perform silk screen printing and UV radiation as described above. Example 14 (see Example 2) Foaming mixture: Cured with UV radiation Composition: Part A: 60% N-methylolacrylamide 87.0 Aqueous ammonia 5.0 Ammonium carbonate 8.0 Part B: Water 37.5 Calcium chloride 52.0 Hydrochloric acid (10M) 2.0 Acetone 8.0 IRGAKI YUA 651 0.5 For part A, mix ammonia water and NMA solution and dissolve ammonium carbonate therein. For part B, the calcium chloride plasticizer is dissolved in water, hydrochloric acid is added, and the photoinitiator catalyst is dissolved in acetone. Combine these solutions and stir rapidly. When both parts are mixed, foaming begins. Radiation can be done with direct sunlight. Example 15 Artificial brick: thermoset composition: 60% N-methylol acrylamide 20.0 Ammonium persulfate 0.1 Sand filler 79.9 The ammonium persulfate catalyst is dissolved in the NMA solution and the filler is then dispersed therein. Production is carried out by continuous extrusion into an oven at 110° for 5 minutes. Radiation is done thermally (from a furnace). Finally, once again, the above-described implementation details for inks and other compositions and printing and other methods are not intended to be limiting. Therefore individually specified examples (for components and monomers)
can be replaced by a functional equivalent,
There are also cases where it is said that oxygen suppression curing is not necessary. As long as the essentially inventive criteria based on new applications of water-soluble monomers in novel compositions and related processes are observed, matters within this scope may be modified according to the needs of the time. be able to. "PRIMAL" and "CONTINEX" are registered trademarks.

Claims (1)

Claims: 1. A composition comprising a dye, a pigment or an auxiliary film-forming material for producing a clean coating, and an aqueous monomer system, the aqueous monomer system comprising at least one water-soluble or water-based monomer system. a miscible or water-dispersible condensation product of acrylamide and an aldehyde or a derivative of N-methylolacrylamide and optionally a photoinitiator catalyst,
The composition is suitable for application to a substrate and is curable in the absence of heat by UV radiation or electron beam radiation in the presence of the photoinitiator catalyst. A polymerizable aqueous coating composition that does not require air drying. 2. Composition according to claim 1, characterized in that the pigment is a pigment for creating a clay coating. 3. A composition according to claim 1, characterized in that the pigment is a pigment for creating a glazed coating. 4. The composition according to claim 1, wherein the aqueous monomer system is a one-component system. 5. A composition comprising a dye, a pigment or an auxiliary film-forming material for producing a clean coating, and an aqueous monomer system, the aqueous monomer system being at least one water-soluble, water-miscible or water-dispersible. acrylamide and aldehyde condensation product or a derivative of N-methylol acrylamide and, if necessary, a photoinitiator catalyst, onto one suitable substrate; Curing the composition by UV radiation or electron beam radiation in the absence of heat and in the presence of the photoinitiator catalyst without preliminary air drying to polymerize the aqueous monomers. A method of coating the composition on a substrate, comprising: 6. The method of claim 5, wherein the substrate is selected from paper, cardboard, wood, metalwork, glass, and woven synthetic surfaces.