DE2334466B2 - Use of solvent-free coating compounds as curable printing inks - Google Patents

Description

The invention relates to the use of solvent-based coating compositions as curable Printing inks that are particularly characterized by fast curing. Under "solvent frci" systems are understood here that are not a solvent in the strict sense of the word and also have no diluents, like water in emulsion systems.

With conventional printing processes such as letterpress printing. Offset printing and rotary light printing will be one Paper web quickly passed through a printing station in which a liquid color is applied to the paper will. Thereafter, the paper is used to drive off the paint composition and solvent The paint is heated dry. The use of volatile solvents in printing processes leads to considerable problems. So that a solution agent Ink composition is useful in conventional printing processes. she must be within be curable for an extremely short time and at temperatures at which no combustion or excessive The paper is dried.

From the DT-C) S 20 13 905 is a method for Bcschichlen a solid surface, in particular a glass container, is known. In this procedure, a hardenable coating agent is applied to the surface in the heated state, which is a monomic or Contains low molecular weight polymer that hardens quickly at surface temperature, and wherein the cured polymer forms a hard and adhesive coating on the surface.

From DT-OS 20 54 680 sprayable and curable Millcl without solvents are known, which as the main polymerizable constituent a cycloaliphatic polyepoxide or polymer dcs- X ₁ - AX,

where X and X _{2 are} identical or different cycloaliphatic rings carrying an epoxide and A is a connecting unit.

The compositions according to the invention can - as will be explained in more detail below - either reactive or non-reactive diluents to control viscosity, pigments and other components. The printing inks have a short duration at suitable temperatures Hardening time.

The masses or compositions can be applied to all solid surfaces that are compatible with this. d. H. which are not attacked by the system and the curing temperature withstand for a short time.

The hardenable mass is applied to a printable Surface, e.g. B. Paper, in a conventional manner using the usual equipment for letterpress printing, Offset printing, rotary light printing or other processes applied. Because of the unique properties of the masses, the color will be within the normal printing processes in which Heat is applied to dry the paint and drive off the volatile solvents Time and temperature ranges, e.g. B. 121 to 204 C, preferably 149 to 177 C and 0.3 to 30.0 seconds, preferably 0.3 to 1.0 seconds, hard.

The cycloaliphatic rings represented by X ₁ and X 2 in the aforementioned formula I are usually cyclohexanes or cyclohexane rings, but they can be 4-, 7- or 8-membered rings or even larger rings. 5- and 6-glicdrigc rings are preferred. The rings can have one or more heteroatoms, e.g. B. O, S or NH, and they can by hydrocarbon radicals such as alkyl, ι. Β. Methyl, ethyl, propyl, butyl, octyl, dccyl etc., aryl, ζ. B. phenyl, ToIyI etc. aralkyl, e.g. B. benzyl, and cycloaliphatic radicals, e.g. B. Cyclohexyl and

Cyclopcntyl. or by other groups such as methoxy, ftthoxy, phenoxy, phenoxy, Cl, IBr, NH ₂ , a substituted amino group, OH, SH, etc. be substituted.

The ring can also be unsaturated. Condensed rings such as dckahydromiphthalene can also be used are present.

In formula I, Λ can represent one or more covalent links between X ₁ and X 2. This is explained in more detail in Table A below. Alternatively, A can be a linking group which, in its composition, ranges from a simple mono-, di- or triatomic group such as - O -, - S -, - NH - or --CH ₂ - to more complex groups, e.g. B. long groups, as shown in the following Table B is sufficient.

Table A.

Covalent links from X to the epoxy-coated, cydoaliphatic ring

Stcrcoisomere is solid at room temperature, the crstcrc liquid form preferred. However, in all cases in which the cycloaliphatic Polycpoxjd is solid, and especially when it melts quite high, its melting point as well Viscosity can be reduced by the application of heat and / or a reactive diluent is used, which lowers the viscosity and the melting point, but the im The hardening process reacts with the cydoaliphatic polyepoxide on a hot surface and therefore does not require evaporation.

Table B.
A as a connecting group

OI -J-CH CH ₂

35

In Table A and in the description, the arrangement of the epoxy oxygen is said to be outside the ring both the endoseal, d. H.

45

as well as the exo position, d. H.

55

60

mean, and these two configurations can be used. If such a! Stereoisomer liquid at room temperature and the other

65

- O -

Q

- NH-O

- c - ο-Ι!

- ο —c -

Il ο

- CH ₂ -
-CHR ₁ -

(CH ₂ ) ,,,

- (CH ₂ J ₁₁ -COO

- OC (CH ₂ ) ,, -

(m = 1—20)
(n = 1-20)

(n = 1-20)
(ti- = 0-20)

Il O

0 ^ 0-

- O - Cl · 4-C-

c — ο—

oil 4-CH —A — C — 0-4-0

4 [

(A '= covalent bond or a linking group)

10

ο—

O
Il O
η O Il
—C— C --Ο - ^c "V O
η O
Η O- Il
> -C —O O —C- O
Η Il
O —C-

In addition, A can have one or more other epoxy-bearing groups, so that formula 1 assumes the following form:

20th

(H)

where X] ₁ X ₂ and _{—X n are} epoxy-bearing groups, π O or c is a positive integer indicating the total number of such epoxy-bearing groups. The following Tris compound is used to explain such higher polyepoxides:

α O CH ₃ O / ν

Il I Il Λκ

^c - ^o -r ^o - ^c V °

35

C = O

(HI)

45

In Table B, R ₁ and R _{2 are} e.g. B. Hydrocarbon groups such as methyl, ethyl, propyl etc .: aryl such as phenyl etc .; Aralkyl such as benzyl, etc .; R ₃ and R ₄ are H, alkyl, ζ. Β. Methyl, ethyl, propyl etc., aryl such as phenyl etc., aralkyl such as benzyl etc., or other groups.

In the formula I, X ₁ and X _{2 can be} identical, ie a bis compound can be present or they can be different. A bis compound is shown in the following formula IA; Formula IB represents a class of compounds in which X _{1 and X 2 are} similar but not identical, and

In the formulas given, rings mean like Cyclohexane Cyclopentane

d. H. fully saturated rings (saturated, cycloaliphatic rings), while through an unsaturation

the formula IC represents a class of compounds 60 is given a double bond, e.g. B. in which these two epoxy-bearing residues are completely dissimilar.

(IA) Cycloxcn and an aromatic ring by the Kekulc-Formcl

is specified.

benzene

It should be noted that mixtures of Any of these cycloaliphatic polyepoxides are just as good like mixtures of these and other cycloaliphatic Polyepoxides with non-cycloaliphatic epoxides such as epichlorohydrin, ethylene oxide, Propylene oxide and diglucidyl ether or bisphenol-A can be used. In all cases where a monomeric epoxide is called, its lower homo- and copolymers can be used in place of the Monomers are used.

Specific examples of suitable, cycloaliphatic polyepoxides are:

S ^ -Epoxycyclohcxylmethyl-S / l-epoxycyclo-

hcxane carboxylate,
3,4-epoxy-1-methylcyclohcxylmethyl-S ^ -epoxy-

1-methylcyclohexane carboxylate, ß ^ -Epoxy-S-methylcyclohexylmethyl-S.'t-epoxy-

2-methyl-cyclohexanecarboxylate, S-Mclhyl-l.S-pentanediol-bis-P ^ epoxycyclo-

hcxane carboxylate),
!, S-Pcntanediol-bis-ß ^ -epoxycyclohexane

carboxylate),
2-methoxy-melhy1-2,4-dimethyl-1,5-pentanediol

bis- (3,4-cpoxycyclohexanecarboxylate), ethylcnglycol-bis- (3,4-epoxycyclohexanecarboxylate)

oxyiate),
2,2-diethyl-1,3-propanediol-bis- (3,4-epoxycyclo-

hcxane carboxylate),
2-Butcn-1 ^ -dioI-bis-Q ^ -cpoxycyclohexanecarb-

oxylate),
2-Butcn-1 ^ -diol-bis-O ^ -epoxy-ö-methylcyclo-

hcxancarboxylal),
1,1,1 -trimelhylolpropane-tris-P / l-epoxycyclo-

hcxancarboxylal),
l ^ -Propanetriol-tris-O ^ -epoxycyclohexan-

carboxylate), dipropylene glycol bis (2-ethylhexyl-4,5-epoxy cyclohexane-1,2-dicarboxylate), diethylene glycol bis (3,4-cpoxy-6-methyl-cyclohexane carboxylate) and triethylene glycol sebacate,

bis (3,4-epoxycyclohexanecarboxylate), S bis (3,4-cpoxybimethylcyclohxylmethyl) adipate,

Bis- (3,4-epoxycyclohexylmethyl) oxalate, Bis-P ^ -epoxy-o-methylcyclohxylmethyl) -S.iMBis-P ^ -epoxycyclohexyO-spirobi-fmeta-

dioxane),
ίο vinylcyclohexane dioxide,

Bis- (2,3-epoxycyclopenlyl) -iither, bis-iepoxycyclopentyl-isophthalate, ! ^, S-Tris-iepoxycyclopentyO-benzene, l-methoxy-S.S-bis-iepoxycyclopentyO-benzene, 1,3-bis- (epoxycyclopentyl) -benzene, bis- (cpoxycyclopentyl) -mcthan, bis-icpoxycyclopentyO-sulfide, Bis (epoxycyclopentyl) ketone, bis (3,4-epoxycyclopentyl) sebacate, I, I, l-trimethylolpropane tris-β ^ -epoxycyclopentyl carboxylate).

It should be noted that in the general -. and specific examples mentioned above »5 and will be mentioned below instead of a 6-membered, cycloaliphatic ring, i. H. of the cyclohexyl ring, a 4-, 5-, 7-, 8- or higher-membered ring can also be used and that the ring has a or several unsaturated groups, jo Furthermore, hetero rings can be used in place of the carbocyclic Rings are used wherever a cycloaliphatic or aromatic, carbocyclic ring is shown e.g. B. furan, pyrrole, pyridine and their fully or partially hydrogenated derivatives. Further can, wherever a replaceable hydrogen is shown, this hydrogen off rest by a coal, z. B. Methyl, ethyl, propyl, decyl, phenyl, tolyl, benzyl, Cyclohexyl, etc., or a hetero radical, e.g. B. methoxy, ethoxy, amino, dimethylamino, etc. are replaced. The hardening agents which can be used for the preferred compositions or compositions are polyvalent Phenols such as low molecular weight phenolic resins of the novolak or resol type. Particularly Modified phenol-aldehyde resins, such as the 2,6-dimethylo1-4-hydrocarbylphenols, can be used and their condensation products, e.g. B.

where R is an alkyl or hydrocarbon radical and π is O to S or 6.

The cycloaliphatic polyepoxides of the classes described and shown are catalyzed by polyvalent metal salts of phenols. Examples of these catalysts are listed below:

Polyvalent metal salts of phenolic novolak resins with the general formula

OH

iV) where a is a small whole number, e.g. B. 1, 2 or 3 is. This resin is referred to below as "HarzV". The metal-forming salts of resin V and other similar resins can contain, for example, Al, Fe (III) and Ti (IV); homologues can be used in which the benzene rings _{are substituted by one or more C 1} - to Gj-alkyl radicals.

Salts of the same metals with polyvalent phenols such as 2,4,4'-trihydroxybenzophenone, 2-nitroso-1-naphthol, 1,2,4-trihydroxyanthraquinone, etc. can be used.

The curable coating compositions can be mixed with a large number of organic and inorganic dyes and pigments

509524/388

become, ζ. B. with soot, titanium dioxide, zinc oxide, azo dyes, Aniline black, phthalocyanine blue, phthalocyanine green, anthraquinone red, anthraquinone blue, Nigrosines, barium lithol red, pigment green B, pigment green 10 and benzinic acid, with mineral fillers, e.g. B. Calcium carbonate, silica, clays, mica, metal powder, with conventional abrasives used in paint compositions such as low molecular weight waxes and with ultraviolet absorbers or shielding means, e.g. B. 2 (2 '- Hydroxy - 3' - di - lert. - butyl - 5 '- methyl - phcnyl) benzotriazole, 2 (2'-llydroxy-5'-di-tert-bulyl-phcnyl) -bcnzotriazole , 2 (2'-Hydroxy-5-methylphynyl) -bcnzotriazole, p-Oclylphynyl-salicylate, 2-ethylhexyl-2-cyano-3,3 - diphynyl acrylate, ethyl - 2 - cyano - 3,3 - diphynyl acrylate, 2,4 - dihydroxybenzophynone, 2,2 '- dihydroxy -4,4'-dimethoxybenzophynone, 2,2 ', 4,4'-tetrahydroxybenzophynone, 2'-Hydroxy-4-methoxy benzophynone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfonbenzophynone, Rsorcinol mono-benzoate, nickel-bis-octylphonyl sulfide, [2,2'-thio-bis (4'-tert-octylphenolate)] -n-butylamine nickel. The selection and the application Such additives naturally depend on the particular use of the curable mass.

The viscosity of the curable masses can be regulated. For paints, the viscosity must e.g. B. be low enough that there is good flow and uniform coverage with no build-up. However, it must be high enough to prevent it from penetrating the paper or the other printed matter Avoid surfaces. The viscosity of the masses can be within the range normally found in paints Ranges, e.g. 1500 to 5000OcP can be set. For other applications, e.g. B. if the curable mass is sprayed or injected, the viscosity can be lower. The viscosity of the Curable mass can to some extent by the amount of hardener, pigment or other Additives that are present are regulated. However, the invention also includes the addition of reactive diluents, d. H. Thinners that crosslink with the hardenable mass, or of non-reactive diluents in the hardenable mass, which are not evaporate, but rather become part of the finally hardened mass.

Typical reactive diluents include the glycidyl ethers, such as dccylglycidyl ethers, 1,4-butanediol diglycidyl ethers and poxydicrtes Soybean oil. Representatives of non-reactive diluents are dioctyl phthalate, polyethylene glycol-200-dibcnzoate, alkyl acryl phosphate and non-volatile Ester or ether.

The amounts of the cycloaliphatic epoxy monomer, the phenol aldehyde resin hardener and the catalyst or other constituents can vary within wide limits depending on the particular application. Usually the monomer comprises from 40 to 95 percent by weight and preferably from 60 to 90 percent by weight of the curable compositions. The amount of hardener can vary from 5 to 30 percent by weight and preferably from 5 to 25 percent by weight. The amount of catalyst can range from 0.01 to about 20 percent by weight, preferably from 0.1 to 10 percent by weight. For coloring compositions in which the regulation of the viscosity is more important, the amounts and types of ingredients are as follows:

Art ilcs Ucsuinil- Broiler Area Preferred Area part

Monomcrcs 40 to 80% 40 to 65%

(cycloaliphatic

lic poly-

cpoxide)
Resin hardening 5 to 30% 15 to 25%

middle

Dilution 5 to 20% 5 to 15%

middle

Pigment 5 to 25% 10 to 15% for carbon black

5 to 10% for others

Colours

Abricbsmitlcl I up to 10% 1 to 3%

Catalyst 2 to 15% 5 to 10%

The invention is explained in more detail below by means of examples.

example 1

An uncatalyzed mass was made up of the following Ingredients mixed together:

Type of ingredient Chemical name Quantity

Epoxy monomers 3,4- Epoxycy el ohexy 1- 54.8 methyl-3,4-cpoxy- cyclohexane carboxylate Responsive Decyl glycidyl ether 7.8 Diluents Hardening agents Condensation poly 12.5 merisate of 2,6-di- methylol-4-butyl- phcnol pigment Alkali blue 3.1 Abrasives low molecular weight 2.0 wax Picment soot 19.5

All compounds with the exception of the carbon black and the alkali blue were put together and under Application of heat released. The mixture was then allowed to cool to room temperature, and the carbon black and alkali blue became intimate in the mixture using a three wheel chair dispersed. This basic approach was then used for the subsequent formulations with catalysts used, the finished compositions were obtained for use for printing inks.

Example 2

10 parts of uranyl nitrate were dissolved in 10 parts of methanol, to which 90 parts of dioctyl phthalate and 100 parts of a novolaklyp phenolic resin (formula V) were added. The mixture was ^{heated to 120 °} C. for 1 hour and then allowed to cool before use. A mixture of 5.5 parts of this catalyst with 100 parts of the batch described in Example 1 was processed on an offset printing press and it was found that

9-

it at a rate of about 0.3 seconds and a web temperature of 149 "C a good print quality revealed. The pot life of the compound mixed with catalyst showed in terms of viscosity during no increase over a period of many hours.

Example 3

5 parts of trabulyl titanate were mixed with 50 parts of a phenolic resin of the novolak type (formula V) at room temperature implemented with stirring. In an exothermic reaction, the mixture gave a viscous, brown liquid. 6 parts of this catalyst were used with 100 parts of the basic batch described in Example 1 mixed. ι S.

Example 4

14.7 parts of his (III) chloride were with 35 parts a phenolic resin of the novolak type (formula V) implemented until the wrapping of HCI stopped, κ » \ which was the case in about an hour. A viscous, brown liquid was obtained, which then with 25 parts of dioctyl phthalate was diluted. 6 parts of this catalyst were mixed with 100 parts of the im Mixing the basic batch described in Example 1, or 5 parts of this catalyst were divided into 50 parts of the epoxy monomer described in Example I and 11 parts of the novolak-type phenolic resin (Formula V) introduced.

B c i sp i c 1 5

1 part of aluminum chloride was reacted with 3 parts of a novolak type phenolic resin (Formula V) by heating the mixture to 100 ⁰ C with stirring. The yellow product was then diluted with 4 parts of propylene glycol dibanol. A mixture of 5 parts of this catalyst with 50 parts of the basic batch described in Example 1 gave a curing time of 30 seconds at 150.degree. The viscosity remained constant over a period of several hours.

Example 6

A mixture of 282 parts of freshly distilled phenol and 246 parts of aluminum sec-butoxide was heated with stirring at 150 to 160 ⁰ C boiled for 2 hours under reflux. After distilling off 222 parts of sec-butanol, aluminum phenolate was obtained as a dark brown, hard, resin-like mass. Other aluminum phosphate and crystallate can be made in a similar manner. A mixture of 5 parts of this catalyst diluted with 4 parts of dioctyl phthalate was added to the batch described in Example 1. This paint showed a curing time of 30 seconds at 150 ° C. The pot life for usable paint application exceeded 2 hours.

Example 7

A mixture of 15 parts of distilled m-Krcsol and 11.3 parts of aluminum sck.-butoxide were heated to 150 to 160 ° C. with stirring and for 3 hours refluxed. After the sec-butanol formed had been distilled off, it became a crystalline product obtain. A mixture of 4 parts of this catalyst and the basic batch from Example 1 showed a curing time of 30 seconds at 150 "C. In In the same way, aluminum sck.-butoxide was used with o-cresol and the aforementioned phenolic resin from Novolak type implemented, with catalysts were obtained, the rapid curing with the im Example 1 resulted in the basic approach described and obtained usable masses for a print became.

For various purposes is a relatively high viscosity, which is due to the use of solid hardeners, Pigments such as carbon black and fillers such as fumed silica are advantageously achieved. The colors do not have to exceed speeds of up to 600 m / min at 177 ° C on a printing press Cure temperatures.

On the other hand, the viscosity can be reduced by using a reactive diluent low viscosity such as vinyl cyclohexene dioxide is added. Curing that is too slow can result Using a higher temperature or a more active catalyst or through a prepolymerization be improved. Too rapid curing can be achieved by using a lower temperature and / or a less active catalyst. If the monomer is too volatile, the Volatility can be reduced by a prepolymerization, or a more active catalyst and a lower one Temperature can be applied. The brittleness can be reduced by using a plasticizer such as Vinyl stearate, or by using a catalyst that allows a lower temperature and therefore the oxidation inhibits, be corrected.

Claims (5)

Patent claims: 1. Use of solvent-based coating materials which contain a cycloaliphatic polyepoxide as the main polymeric constituent, a phenol-aldehyde resin as the hardening compound, a polyvalent metal salt of a phenol-like material as a catalyst, a pigment and, if necessary, other conventional additives in the range from 93 to 204 ⁰ C in a period of 0.3 to 30 seconds curable printing inks. 2. Use of solvent-free coating compounds according to claim 1, wherein a polyvalent metal salt of a low molecular weight novolak resin is used as the catalyst. 3. Use of solvent-free coating compounds according to claim 2, wherein the polyvalent metal is aluminum, ice (III) or Titanium (IV) can be used. 4. Use of solvent-free coating compounds according to one of claims 1 to 3, wherein the hardening agent is 2,6-dimethylol-4-hydrocarbyl alcohol resin is used. 5. Use of solvent-free coating compositions according to one of claims 1 to 4, a glycidyl ether being used as a diluent. same mil low molecular weight or a mixture from a dciartig monomers and polymers and a catalyst included, which is composed of a Metal salt of a polysiloxanol or a metal salt a phenolic crystal. In the aforementioned publications, however, there are no solvent-based, printing inks described. The object of the invention is to create improved curable printing inks which are solvent-free at t '.- ncn Coating masses are used. The invention relates to the use of solvent-based coating compositions which have a cycloaliphatic polyepoxide as the main polymeric constituent, a phenol-oxide resin as the hardening agent, a polyvalent metal salt of a phenol-like material as a catalyst, a pigment as well as optionally contain other customary additives than in the range from 93 to 204 "C in a period of Inks curable for 0.3 to 30 seconds. A polyvalent metal salt of a low molecular weight novolak resin is preferably used as the catalyst used, with aluminum, ice (III) or titanium (IV) being used in particular as the polyvalent metal will. The cycloaliphatic polyepoxide can be represented by the following general formula: