DE1191067B - Coating agents to be hardened with high-energy light and subsequent heating - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. σ .:

Number:
File number:
Registration date:
Display day:

C09d

German class: 10 p.m. - 3

M39848IVc / 22h 4th December 1958 15th April 1965

Coating agents to be hardened with high-energy light and subsequent heating

Applicant:

Minnesota Mining and Manufacturing Company, St. Paul, Minn. (V. St. A.)

Representative:

Dr.-Ing. H. Ruschke, patent attorney, Berlin 33, Auguste-Viktoria-Str. 65

Named as inventor:

Wesley Ray Workman, St. Paul, Minn.

(V. St. A.)

The invention relates to coating agents to be hardened with high-energy light and subsequent heating, the at least two epoxy-containing, optionally resinous compounds and nitrogen-containing compounds Compounds and optionally contain fillers.

A large number of curable compounds or compositions containing epoxy groups and curing agents are known. Typical examples of such epoxy compounds are the glycidyl ether of bisphenol A, aliphatic glycidyl ethers, glycidyl esters such as polyglycidyl methacrylate, and bisepoxy compounds such as vinyl cyclohexene diepoxide. Other typical epoxy compounds are described in Modern Plastics Encyclopedia Issue, Vol. 35, No. IA, p. 105, September 1957. As a hardener, for. B. acid anhydrides or amines are used. The curing usually takes place by heating a mixture of the epoxy compound and the curing agent to higher temperatures. Particularly when using the acid anhydride as the curing agent must be heated to well above 120 ⁰ C it. However, curing is initiated immediately after the curing agent has been mixed with the epoxy compound, and exothermic reactions can occur spontaneously, leading to rapid insolubility and complete curing. As a result, after the curing agent has been added, in most cases the time during which the resulting reaction mixture can be handled at temperatures sufficiently elevated to maintain viscosity is unusually short (ie, the "life" is very short). This is generally not a problem if, after mixing with the hardener, only simple processing methods, e.g. B. a casting should be carried out. So far, however, it has not been easy to produce epoxy resins in self-supporting skins or in thin moldings, unless using suitable molds in conjunction with mold release agents. Because of the good mechanical properties, e.g. B. toughness, the insoluble epoxy resins, however, the utility of epoxy resins in coatings has already been investigated and recognized. Used

the resins for the production of coatings in j

Solution, the best possible insolubility cannot be r

can be achieved.

From French patent specification 1 172 303 it is contained in which η = 1 or 2, R _{1 is} a hydrogen atom, the selected curing of mixtures of poly 50 is an alkyl radical with 1 to 7 carbon atoms, R _{2 is} epoxies and nitrogen-containing compounds and R ₃ Hydrogen atoms, alkyl or cycloalkyl radicals known high-energy light. As nitrogenous are, the total number of carbon atoms of

509 539/389

Compounds were azidobenzoic acid or aminobenzoic acids and condensation products from p-nitrosodimethylaniline and hexahydrodiphenylamine are used.

The coating compositions according to the invention are now characterized in that they are nitrogen-containing Compounds contain those which have an N-nitrosoamine group in -position to a reactive one Have carbon double bond adjacent carbon atom.

The coating compositions according to the invention contain compounds containing N-nitrosoamine groups, preferably those of the general formulas

R ₄

R ₄

NO R ₁ R ₂

_N - C = C- R _a NO Z

I / \

- N - C = C - R ₃

ON-NC = CR ₃

3 4

R ₁ , R ₁ and R _{8 is} not greater than 16, R _{4 is} an alkyl, (2-methylpropenylnitrosamino) hexane, 1,4-bis (2-cyclo-

Alkenyl, aralkyl, cycloalkyl, alkylene, aralkylene hexylvinylnitrosamino) butane, 1,8-bis (2,2-dicyclo-

or cycloalkylene radical, in which the ethylene double hexylvinylnitrosamino) octane, l, 4-bis (l, 2-dicyclo-

bond around at least one carbon atom of a hexylpropenylnitrosamino) cyclohexane, 1,3-bis (vinyl-

Valence position is removed, Z is a divalent radical 5 nitrosoaminomethyl) benzyl, 1,2-bis (propenylnitroso-

with the formation of a five- or six-membered aminoethyl) benzene and l, 4-bis (2-methylpropenyl-

Ringes required number of carbon atoms. nitrosoamino) cyclohexane.

From those compositions according to the invention which in In the formulas given above, Z represents a

Organic solvents are soluble, can be according to alkylene groups, which have 2 to 4 carbon atoms in

the action of high-energy light in the io of a chain contains and terminally available valences

Thermosetting, un- in organic solvents, like 1,2-ethylene-, 1,3-propylene-, 1,4-Bu-

soluble molded articles (molded parts) manufactured tylene-, 2-methyl-l, 3-propylene-, 2-ethyl-l, 3-butylene-

will. Furthermore, from the group according to the invention and other such groups, the total

Mass sheet structures are produced which contain no more than 8 carbon atoms. Examples

high-energy light can be hardened. Thereby 15 for nitrosamines, which for the purposes of the present

is a selective or different curing invention are suitable and the general formula possible. With hooves of the masses according to the invention

can still produce layered items Z

the load-bearing surfaces with / \

borrowed have raised signs, which from the 20 R ₃ —C = CN - NO
hardened epoxy resin compound.

It has also been found that when the actinic R ₁
Light the mixture according to the invention of epoxy compound and hardener through a cover sieve, for. B. have, N-nitroso -Δ ² -tetrahydropyridine, a photographic negative, achieved, the obtained 25 5 ethyl 6 -methyl- N- nitroso -A ³ - tetrahydropyridine, sheet after heating and removing the soluble, N- Nitroso / l ² -dihydropyrrole, 2-methyl-N-nitroso non-hardened epoxy compound by a solution ^{I 2} -tetrahydropyridine and 3-ethyl-N-nitroso- ^{I 2} -tetramittel a raised positive image of the hydropyridine used. Examples of nitrosamines that are used for the negatives because only the light exposed purposes of the present invention are useful. Areas have been hardened and made insoluble. 30 and the general formula
The positive image obtained can be used as a printing plate for

Used for printing purposes. r j ^ o Ζ

The "^ -unsaturated nitrosamines, which are found in the

inventive masses as usable by light _R Jj c - r P

activated hardeners can be used, 35 ⁴ L ~
generally as derivatives of methylvinylnitrosamine

are designated. They all have a basic chain, are methyl-Zl ^ cyclohexenylnitrosamine,

of the formula phenethyl-zl ¹ -cyclohexenylnitrosamine, cyclohexyl-

Nö / P-cyclopentenylnitrosamine, butyl-2-methyl-zl ^ cyclo-

III 40 pentenylnitrosamine, 1,4-bis (J ¹ -cyclohexenyl-nitros-

N C = C amino) -butane and l ^ - ^^ cyclopentenyl-nitrosamino-

methyl) benzene.

Certain members of this series have several. The N-nitroso compound is preferably in one

of these basic chains. An example of such an amount of about 0.01 to 4 equivalents per equivalent

Compound that applied two vinyl nitrosamine groupings 45 epoxy groups.

contains is 1,2-bis (propenylnitrosamino) ethane. Any suitable inert solvent can be given examples for suitable formulas given above, if for the preparation of a liquid mixture if the epoxy compound chosen

is a solid substance. Then the

50 masses are kept until they are used without any change, provided that that these are not exposed to light. Optionally, the solution of a solid resin prepolymer

corresponding compounds are methylvinylnitros- are poured onto a support, whereupon the

amine, ethylvinymitrosamine, butylvinylnitrosamine, 55 solvents for the purpose of forming a dry,

Octylvinylnitrosamine, dodecylvinylnitrosamine, allyl-layered sheet or film structure is evaporated.

vinylnitrosamine, methallylvinylnitrosamine, but-3-enyl- The masses or the counter-

vinylnitrosamine, dec-9-enylvinylnitrosamine, benzyl levels are in subdued light or in the

vinylnitrosamine, phenylbutylvinylnitrosamine, cyclo- dark handled and stored until it

Pentylvinymitrosamine, cyclohexylvinylnitrosamine, 60 are meant to be cured.

Ethylpropenylnitrosamine, Allyloct-1-enylnitrosamine, If the masses are to be hardened

Benzylpropenylnitrosamine, Cyclohexyl-dec-l-enyl- they turn off actinic light for an effective period of time-

nitrosamine, phenylbutyloct-1-enylnitrosamine, oct- set. This initiates hardening, whereupon

7-enyl-oct-l-enymitrosamin, ethyl-l-methylpropenyl by heating at temperatures up to about 15O ⁰ C

nitrosamine, phenylethyl-oct ^ -en ^ -yl-nitrosamine, 65 for a time of about 3 minutes up to 3 days the

Methyl-dec-4-en-4-yl-nitrosamine, butyl-2-ethyl-but-epoxy compound hardened to a hard mass

1-enymitrosamine, 1,2-bis (propenylnitrosamino) ethane, is practically insoluble in any solvent

A, 3-bis- (1-methylpropenylnitrosamino) -propane, 1,6-bis- is. The desired impact of actinic light is

Γ NO R ₁ R ₈ R ₄ -JNC = C-

apparently a "photolytic effect," which denotes the effect of actinic radiation which is intended to effect photolytic decomposition of the exposed Λ, / 3-unsaturated nitrosamines sufficient with the existing concentration. The photolytic curing agents of the present invention Invention apparently show their maximum sensitivity in the ultraviolet region; the actinic The radiation source should therefore have the maximum radiation in this spectral range. The one with it The decomposition products formed are not exactly known, but it is currently assumed that these contain at least some secondary amine and possibly a Schiff base (cf. C. H. Bamford, Journal of the Chemical Society [London], 1939, p. 12).

The exact duration of exposure to actinic light that will be effective to initiate cure is obviously determined by a number of factors such as film thickness, light intensity and the distance of the light source from the hardenable composition. With a relatively thin layer in which the absorption by the epoxy compound is only slight and simultaneous If there is little nitrosamine present, only a short exposure is necessary, whereas thicker ones Layers and a higher content of unsaturated nitrosamine require a longer exposure time will be.

By exposing the mixture from the soluble Epoxy compound and the nitrogen-containing compound of the invention with high-energy Blasting and subsequent hardening result in solid, heat-hardened, insoluble molded parts or coatings produced.

A great deal of leeway is possible in the choice of epoxy compounds or compounds. The epoxy compound should preferably be practically free of groups or additives like the quinones in one Strongly absorb light in the range of about 3200 to 4000 angstrom units. It is usually preferred Epoxy compounds, either alone or in admixture, should not be used before curing are sticky or soft, but if a clear, removable protective sheet is used in between the epoxy compound and the negative even liquid epoxy compounds can be used. the Epoxy can be customized according to the desired properties, such as hardness, color and electrical properties, which the hardened material is to have, are selected, the hardenable compositions e.g. B. modified by incorporating finely divided, preformed polymers or inert fillers which absorb light in a range of 3200 to 4000 angstrom units neither disadvantageously, reflect, which would otherwise prevent the curing agent from being irradiated, nor the epoxy compounds cure spontaneously. Such additives can be classified as "non-protective" or "inert" Additions are designated. Suitable epoxy compounds, which are in the masses of the present Invention may be used include e.g. B. the diglycidyl ethers of 4,4'-dihydroxydiphenylpropane (Bisphenol A) of the general formula

H ₃ H

C - C-CH ₂ -

O— 1

CH ₃

c — 1 ₅

CH ₃

-OCH ₂ -CHOH-CH ₂ -O

HH ₂ i-O-CHo-C-C

in which m = 0, 1, 2 or a number up to about 20. An epoxy compound of the general formula given above, in which m has an average value of about 0.3, and an epoxy compound, which has a softening point of about 64 to 76 ° C and has the same formula given above, in which m is about 2, are suitable within the scope of the invention.

The organic inert solvents in which the uncured coating materials are used for manufacture of films or removal of the unexposed and uncured epoxy compounds are those known to be useful for such a purpose.

Plating may have the most benefits depending on the procedure that is used for a particular purpose offers, from solution, by applying a molten material, by painting, brushing or Immersion.

The specified exposure times indicate the required conditions. Because this implementation runs to the end, overexposure is usually preferable when it is uncertain whether the entire exposed area is cured in the heating stage, while not exposed or only weakly exposed areas can then be removed by washing with a solvent. Trial exposures of portions of the curable mixture are the most suitable means, those required Determine minimum conditions.

The heating step of the process, the epoxy compound is completed by the initiated by light curing is usually carried out at temperatures between about 50 and 150 ⁰ C. If z. B. α, 5-nitro unsaturated amines are used /, dissolved in thin layers of the epoxy compound, the heating step may be carried out in a relatively short time by heating at about 140 to 150 ⁰ C. Unsaturated amine are heated, this temperature may be 50 ⁰ C only - in other cases, at temperatures below the decomposition point of the "used, ^. A temperature between approximately 80 and 120 ^° C. is preferably used. The heating stage can be carried out separately or simultaneously with the exposure with the aid of circulating hot air, a heated metal plate behind the plate or the like. This shortens the processing time.

The following examples serve to illustrate the invention. Unless otherwise noted, all are Parts parts by weight.

example 1

A 10% solution of methylvinylnitrosamine in an epoxy compound (a liquid resin of the above

given general formula, in which m has a value of about 0.3) is prepared by mixing 1 part of the nitrosamine with 10 parts of the resin. The mixing and handling of the resulting mass takes place in subdued yellow light. The homogeneous, viscous solution obtained is divided into four equal parts, whereupon each part is poured onto glass to form an approximately 1 mm thick test layer. Two of the specimens are exposed at a distance of about 20 cm with the light of a high pressure mercury vapor lamp which emits high intensity ultraviolet light in a range of about 3200 to 4000 Angstrom units. The other two specimens are not exposed to light. One sample each of the exposed and unexposed material is left to stand at 25 ^° C .; the other two samples are heated at 9O ⁰ C. The preserved at 25 ° C samples were not hard even after 2 days of standing, although the light-exposed sample after 2 days showed a small increase in viscosity, while not noticed test piece did not change significantly even after 60tägigem standing at 25 ⁰ C and even after two days was still liquid at 90 ⁰ C. In contrast, the exposed specimen heated to 90 ° C. hardens within 5 hours, which shows the latent hardening initiated by the irradiation.

In Example 1, the molar ratio of methyl vinyl nitrosamine to the epoxy equivalent is about 0.23: 1.

Example 2

A solution of 20.0 parts (1 molar equivalent of oxirane groups) of polyglycidyl methacrylate and 6.0 parts (0.5 mol) methylvinylnitrosamine in 40 parts of dioxane is in a 0.13 mm thick layer Silica-treated aluminum is applied so that when it dries a layer with a thickness of about 0.05 to 0.076 mm remains. The plate is then protected from light and dust Avoid draining, dried.

A halftone negative of about 49 lines per centimeter is placed emulsion side up on the dry plate without the interposition of any membrane, and the plate is exposed to light through the negative in a lighting fixture. After exposure, the plate is ^{heated to 140 °} C. for 3 minutes. Although this temperature is above the normal thermal decomposition temperature of methylvinylnitrosamine, decomposition is not observed if the coating is less than 0.013 mm thick. An equally satisfactory process is followed by heating to a temperature of 120 ° C. for 15 minutes after exposure.

After exposure and heating, the plate is immersed in acetone and then dried. Vigorous washing or rubbing that may result in loss of detail or damage to the Form of mark is because of the ready solubility of the epoxy compound in this Solvent not required. The plate produced by this method is satisfactory as a dry offset plate. You can post to print Letter printing processes can be used in the same way as an etched plate.

The coating agents according to the invention are particularly suitable for the production of books for the blind, by exposing coatings on thin, tough plastic sheets, e.g. B. made of polyethylene terephthalate, through a negative of the Braille script and fixing and developing, as already described, getting produced. The opposite side of each sheet can be coated and "printed" using this process. , whereby a larger content can be achieved than by conventional methods. When a thin carrier sheet on plastic, coated with a UV-absorbing material such as carbon black or iron oxide, is filled and coated on both sides with the photosensitive epoxy resins, is used simultaneous exposure of both sides possible, which increases the production speed will.

Claims (2)

Patent claims: 1. With energetic light and the following Heating coating agents to be hardened, which have at least two epoxy groups, optionally resinous compounds and nitrogen-containing compounds and optionally fillers contain, characterized in that they are used as nitrogen-containing compounds contain those which have an N-nitrosoamine group in the α-position to a reactive one Have carbon double bond adjacent alkyl-substituted carbon atom. 2. Coating agent according to claim 1, characterized in that it is used as N-nitrosoamine groupings Compounds comprising those of the general formula NO R ₂ -Ν - C = C- R ₃ Γ NO Z / \
NC = CR ₃ ON-NC = CR ₃ contain, in which η - 1 or 2, R _{1 is} a hydrogen atom, an alkyl radical having 1 to 7 carbon atoms, R ₂ and R _{3 are} hydrogen atoms, alkyl or cycloalkyl radicals, the total number of carbon atoms of R ₁ , R ₂ and R ₃ is not greater than 16, R _{4 is} an alkyl, alkenyl, aralkyl, cycloalkyl, alkylene, aralkylene or cycloalkylene radical in which the ethylene double bond is at least one carbon atom away from a valence position, Z is a divalent radical with the is the number of carbon atoms required to form a five- or six-membered ring. Documents considered: French Patent No. 1 172 303. 509 539/389 4.65 © Bundesdruckerei Berlin