DE2159303C3 - Complete curing of polymerizable films - Google Patents

Description

Its only purpose is to prevent the Effect wax or paraffin to the surface , {Column 1, line 60, to column 2, line 8).

* So the problem of oxygen inhibition became so far always solved in such a way that one works either with the use of paraffins or waxes, the

! «Bf the surface form a protective film, or the

Hardening in a vacuum or under a protective gas atmosphere

| 4urchfüfart Just US-PS 3,531,317 shows completely

! It is clear that despite the use of UV

, Radiation and electron beams for excluded

UeIt, when working without protective gas or without

* Twist or vacuum to the protective wax. "To dispense paraffin film. This makes \ clear that they sought the solutions for the identified 'problems in a completely different direction. The comparison I drive to the invention has therefore not obvious, and who scored technological progress must be regarded as surprising in ^one highly. This all the more is done to as the inventive curing the surface layer without the use of activators and / or catalysts polymerizable in curing films with UV radiation alone in practice are always required.

According to the method of the invention, the coating films can be fully cured using a powerful UV light source, usually lasting less than 1 minute Irradiation can be achieved. This means that insufficiently hardened surfaces can quickly become damaged by the action can be eliminated by UV light even if the film to be cured does not contain free radicals Contains forming catalysts or photoinitiators.

A particularly advantageous system for the rapid and complete curing of polymerizable films results from the combination of an electron beam with ultraviolet light. Through the application the first-mentioned radiation, relatively thick and opaque films can be hardened so quickly that no blistering due to volatile components and no excessive absorption of the uncured film occurs through porous substrates. The thin, incompletely cured surface layer that usually remains is easily penetrated by the UV light and cures quickly.

The method of the invention can be applied to any polymerizable film, with the exception of a thin one, due to the oxygen inhibition of the ionizing radiation induced polymerization incompletely cured surface layer, cured by exposure to ionizing radiation will. As a rule, such mixtures comprise masses which are radically polymerizable. One to prefer: The class of such masses are the polymerizable resins with terminal acrylate or Methacrylate groups, which are known from German Offenlegungsschrift 1916 500, are hereby referred to Is referred to. These resins can be used neat or dissolved in up to 50% of a vinyl monomer be used.

Other polymerizable compositions which can be used for the process of the invention are those in the USA patent 3,437,514, to which reference is also made, described α, / 3-olefinically unsaturated organic resins. Such resins include unsaturated polyester resins, acrylic resins, modified ones Acrylic resins, urethane-modified organic resins, silicone-modified organic resins and Epoxy resins.

Vinyl monomers in which the above-mentioned resins can be dissolved include, for example monovinyl aromatic hydrocarbons of the benzene series, such as styrene, vinyl toluene, ethyl vinyl benzene, Isopropyl styrene, tert-butyl styrene, sec-butyl styrene and mixtures of the compounds mentioned, ot-methylstyrene, divinyl compounds of the benzene series, such as divinylbenzene, acrylic acid, vinyl acetate, diacetone acrylamide, Methyl methacrylate, ethyl methacrylate, n-butyiacrylate, ethyl acrylate, cydohexyl acrylate, yS-hydroxyethyl acrylate and the like.

The term "ionizing radiation" is intended in the present description and the claims both Corpuscle beams, such as highly accelerated electrons, protons, neutrons, alpha particles, deuterons and ^ -rays, as well as electromagnetic waves such as X-rays and y-rays. The dose of ionizing radiation required to cure a particular film depends on the radiation power or intensity, the temperature and the thickness and composition of the film to be cured. Will be useful results for example, using high-energy electrons with? .O KeV to 10 MeV and radiation powers from 1 megarad per minute to 10 megarad per second. Electron beams are preferred with sufficient voltage or sufficient energy content and thus high intensity or Radiance applied so that it penetrates the full thickness of the film to be cured and the film cure in a few seconds or less.

Any UV light sources, including short-wave fluorescent lamps, long-wave fluorescent lamps, mercury vapor lamps and even sunlight, can be used to carry out the surface curing used in accordance with the invention. Light sources emitting short-wave light, however, remove incompletely hardened surface layers much more quickly than long-wave light sources. Where the rate of surface cure is a concern, powerful quartz mercury vapor halogen lamps are particularly preferred. Radiation intensities or densities of about 0.78 to 2.33 W per cm ⁸ and minute are preferably used, but lower radiation intensities can also be used if longer curing times can be tolerated -Light depends on the intensity or radiation density of the UV light source, the degree to which the surface in question is incompletely cured and the composition of the film. With a 1200 W quartz mercury vapor lamp spaced about 7.5 cm apart, surfaces can usually be cured to the desired extent in about 2 to 20 seconds.

As already mentioned above, a rapid surface curing can be achieved using UV light even in the absence of a catalyst or photoinitiator which forms free radicals achieve. In some cases, however, by adding a free radical forming catalyst, such as Benzoyl peroxide and azobisisobutyronitrile, or a photoinitiator such as benzoin and 2,3-butanedione, a even faster removal of insufficiently hardened

5 6

Surfaces srziekn. In addition, the vision under the reflector is also revealed, which leaves behind energy from unscratching no more white scratch marks on the upper filter UV light sources are more effective when the surface and the surface shows the same hardness Photo initiators are present, properties like an identically composed,

The method of the invention is particularly suitable, however, in contact with a cover film made of polygut for curing films in the form of clear excess ethylene terephthalate, which is applied to prevent the extracts on hard plywood, chipboard, cover hardening inhibition by oxygen, flexible plywood, fiber boards and cardboard hardened cover,
and for hardening pigmented coatings, the B is ρ ie 1 3
for example titanium dioxide, calcium carbonate, zinc io

oxide or talc, on wood cuttings, hard The coating agent of Example 2 is with cardboard, plywood., steel, tin and aluminum. The one part glycidyl acrylate and 0.5 part benzoin ver process the invention also lends itself well to sets. After hardening with an electron hardening of carrierless films and for curing beam analogous to Example 1, the coating is hard Surfaces more porous, with hardening by ionizing 15, but has a sticky surface. To Radiation-curable liquids impregnated with 5 times performing under the beterialien in Example 2. For example, you can write an impregnated 1200 watt lamp with a speed pier and wood according to the method of the invention at a speed of 6.1 m per minute, corresponding to a GePaper plastic and wood-plastic combination total exposure time of 5 seconds, the upper sticks Harden. 20 no more surface and stay on it when scratching

The examples explain the invention and are not returned in any white scratch marks,

in no way to be understood as a limitation. Information as per 1 4

in parts, unless otherwise stated, ^

always on the weight. Analogously to Example 1, plywood is made with one as follows

35 composite coating agent coated

Example 1 _unc j ^ ₆ layer irradiated with an electron beam:

It becomes a coating agent by dissolving

20 parts of butyl acrylate in 80 parts of a by Kon- a) 17.5 parts by condensing 2 moles of 2-Hy-

condense 2 moles of 2-hydroxyethyl acrylate, 2 moles of hydroxyethyl acrylate, and 2 moles of maleic anhydride

Maleic anhydride and 1 mole of bisphenol A diglycidyl ether and 1 mole of bisphenol A diglycidyl ether

Dylether obtained vinyl ester resin produced. Then made vinyl ester resin;

a 0.076 mm b) 17.5 parts is applied to a hard cardboard blank by condensing 2 mol of 2-hystyrene layer of this coating agent on hydroxypropyl acrylate, 2 mol of maleic anhydride. The coated blank is then produced twice and 1 mol of butanediol diglycidyl ether at a speed of 15.24 m per Mi- 35 vinyl ester resin;
groove under an electron beam of 300KeV and c) 15 parts of n-butyl acrylate;
20 mA carried out. The electron beam has d) 30 parts of titanium dioxide and
a trailing edge or a scanning width of 45.72 cm. e) 20 parts of talc.
The total radiation dose for this treatment is 8.5 megarads. The applied layer hardens. The resulting hard, resilient, white coating hardens well, but the surface of the so made has a sticky surface that is then slightly sticky to hardened coating and can easily be hardened to a tack-free surface by scratching . The coating is then applied in the manner described in Example 2 6 times with a 100 W at a distance of 3.81 cm at a speed of 18.3 m per minute, quartz mercury lamp for 30 seconds without an in-between 45 corresponding to a total exposure time of 2 The switched-on filter irradiated. After cooling down under the 1200 W UV lamp, the surface shows no trace of stickiness. -ic
on and when scratching with a coin stick to the example
her back no white scratch marks. A conventional unsaturated polyester resin, _. . . . Polylite 31-583 50 (a semi-hard, unsaturated, in vinyl 15 e ι s ρ ι el l _{toluo, dissolved} p _o] y _e art. Product of Reichhold

Analogously to Example 1, a 0.127 mm thick layer of Chemical Co.) is applied to a metal foil in a 0.127 mm thick layer composed of 25 parts of n-butyl acrylate and 75 parts. After three cycles of the vinyl ester resin used in Example 1, the coating agent under the electron beam according to Example 1 is applied to plywood at a speed of 18.3 m per minute, whereupon the coated plywood sheet is suddenly broken when it is bent, but it is using an electron beam analogous to Example 1, the surface is still sticky. After 10 x-rays. The coating obtained in this way also started out hard under the 1200-cured method described in Example 2 and has a tacky surface. The watt lamp with a speed of 6.1 m per coated board is then with a speed of 60 minutes, corresponding to a total exposure time of 6.1 m per minute in about 7.5 cm distance 10 seconds, is the surface of the Films hard and under a 12 "long, with a 4" non-sticky,
wide reflector equipped 1200 W Hanovia.
Quartz mercury arc lamp carried out. After five examples 6
successive passes, the surface is 65. By reacting 100 parts of polypropylene, it was no longer tacky, but on scratching, it takes up glycol with a molecular weight of 400 with white scratch marks. After five more transit 78.2 parts of tolylene diisocyanate, 91 parts of 2-Hydroxygängen that ethylacrylate a Gesamtexponierungszeit of 10 seconds and 0.2 parts of tin octoate at 6O ⁰ C is

a resin solution prepared. This resin solution is applied in a 0.102 mm thick layer on cardboard, whereupon the coated paperboard is irradiated by running it three times at a speed of Performs 25.6 m per minute under the electron beam described in Example 1, which is a total radiation dose of 6 megarads. The clear coating obtained is flexible and strong, has however, has a sticky surface. The paperboard is then made five times under that described in Example 2 UV lamp carried out, whereby a non-tacky coating is obtained.

Example 7

Example 6 is repeated, however, in deviation therefrom, a 0.178 mm thick layer is applied to the cardboard will. The same results as in Example 6 are obtained.

Example 8

The pigmented coating agent mixture of Example 4 is mixed with 0.5% benzoin and in a 0.279 mm thick layer on top layer plywood

carried. As in Example 1, the coating is made in three passages at a speed of 18.3 m irradiated per minute, giving a hard but tacky coating. After five rounds at a speed of 6.1 m per minute under the UV lamp described in Example 2 the surface is no longer sticky and is no longer scratched by a coin.

Example 9

Example 8 is repeated, but deviating therefrom after irradiation with an electron beam hard but tacky coating obtained at a distance of 7.62 cm under a 30.48 cn long 1800 watt "Chromolux" infrared lamp equipped with a 10.16 cm wide reflector to be led. After ten passes at a speed of 18.3 m per minute, there is no ver detect a reduction in surface tack. Be

ao the coating is continuously blasted for several se announce with the infrared lamp, so the upper changes color dark surface without its stickiness being eliminated.

Claims (3)

Material Inherence Insufficiently Hardened Surface Claims: As a rule, layers can be avoided by treating the non-hardened FOm with an inert one 1. Process for full curing of cover sheet covers or so long in an oxygen polymerizable Film that by irradiating S maintains a free atmosphere until it is cured This have been cured with ionizing radiation, however, techniques are often not appropriate in practice. - mod due to oxygen inhibition an incomplete or for large-scale production processes Dig have hardened surface layer, because the scale is too expensive. characterized by the fact that this D, * invention is therefore based on the object Surface layer with UV light for so long ίο a process for complete curing poly-wired, until it is hardened to the desired extent to create merisable fumes, which after loading 2. The method according to claim 1, characterized marked radiation with ionizing radiation insufficiently drawn that one has electrolytic hardened surface layers as ionizing radiation,
Electron radiation uses the subject of the invention is thus a method 3. The method according to claim 1 or 2, characterized xs for the complete curing of polymerizable characterized in that the UV light source is a film which is produced by irradiation with an ionizing beam quartz mercury vapor arc lamp used. treatment have been hardened and as a result of oxygen inhibition have an incompletely cured surface layer, which is characterized in that ao one this surface layer for so long with L V light irradiated until it is hardened to the desired extent. Compared to the method of the invention, the known methods differ in various ways Respect. The invention relates to a method for completely * 5 From DT-AS 1 163 014 is a method for compacting Curing of polymerizable films that are produced by crosslinking thermal radiation that can be crosslinked by UV radiation Moplastics have been cured with ionizing radiation. In this process, the and, due to oxygen inhibition, an incomplete thermoplastic to just below the softening temperature »Have a permanently hardened surface layer. temperature and in this state a UV radiation It is known that numerous polymerizable 3 <> treatment (claim 1, as well as column 1, lines 20 Systems with ionizing radiation can be cured to 23). Since it is not about the cross-linking of polymer the can. The use of ionizing radiation sizable masses, as in the method of the invention, and especially of electron beams, but rather the cross-linking of thermoplastics. Compared to the conventional methods of polydelt, the problem of oxygen inhibition arises merize and crosslink polymerizable systems 35 initially not at all. Apart from that, however, takes place when using catalysts, especially irradiation with UV light not in air, then have a number of distinct advantages when film but in a vacuum or in an inert gas atmosphere Coatings are held on wood and wood products, fabrics, spheres, being crucial for networking Rubber, glass, metal and similar substances or the temperature (column 2, lines 40 to 46). Substrates are to be hardened. 40 FR-PS 1 217 565 relates to surface finishing For example, by using the ionic improvement of plastics by treating them with animal radiation as a polymerization initiator, IR radiation, whereby a momentary melting occurs which can be observed during curing with catalysts or a surface change up to the flowable long-lasting induction period takes place, which the desired surface finish should result in the use of film-forming mixtures without any criticism (left column, paragraph 3). Thus, a limited pot life enables the temperature rise to keep the application of IR radiation low in the FR-PS during the polymerization and in 1 217 565 for surface heating of the plastics, in many cases a superior bond between the results of the application of the IR coating and Substrate can be achieved. Much radiation after the application of ionizing films can be cured using high-energy radiation, from Example 9, the present shear electrons in less than 1 second. Registration can be seen, although treatment with Unfortunately, if the uncured film IR radiation is allowed to come into contact with air with ionic air before extensive curing, the soothing radiation is often not possible due to the volatility of the oxygen inhibition of the curing with monomers mentioned is.
ionizing radiation in the surface layer, 55 The process of US Pat. No. 3,531,317 relates to the curing of unsaturated polyester resins which are sticky or otherwise not so well penetrated by wax or paraffin. D «hardens like the bulk of the film. Although curing takes place in such a way that the polyester resins only incorporate a photosensitizer in a very thin layer of incompletely cured material, then the poly layer, ie in layers with a thickness of large-ester resins, cures with UV radiation until the wax is properly 2.5 ^s is present 10 ~ to 2.5 x 10 "· cm, or paraffin on the surface results in a protective this superficial insufficient curing frequently film is formed, and then treated with electron beams to severe loss of gloss and problems (claim 1). the US-PS 3,531,317 with regard to scratch resistance or waxing, the coated substrates being stored in stack form prior to hardening by electron beams s blocking occur. Due to acidic application of UV radiation only and