DE1297269C2 - UNDER THE INFLUENCE OF ULTRA-VIOLET LIGHT IN THE COLD, HARDENABLE POLYESTER RESIN MIXTURE FOR THE PRODUCTION OF COATINGS - Google Patents

Description

The invention relates to a polyester resin mixture curable in the cold under the influence of ultraviolet light for the production of coatings, consisting of styrene and a curable polyester made from an unsaturated carbonic acid and a dihydric alcohol.

It is known that mixtures of unsaturated polyesters with monomeric polymerizable compounds to stimulate crosslinking through interpolymerization by initiators. Be as initiators predominantly organic peroxides, but also other radical-forming substances, e.g. B. from the azo series, such as Azo-isobutyric acid dinitrile, is used. At room temperature there is a noticeable change in the Reaction mixture only after a long time, about 20 hours and more, a, so that on this Wise moldings and coatings cannot be produced.

It is therefore customary to effect the crosslinking in the presence of the peroxides either by heating Temperatures of 80 ° C and above or - at room temperature - by activators, as in that Mixture of substances soluble cobalt compounds, tertiary amines, azomethines, etc .. initiate.

In this way, gel times as short as 3 minutes can be achieved * with below Gelierzeil is to be understood as the period of time that begins with the mixing together of the reactants and ends when gelatinization occurs. Experience has shown that they generally have short gel times short curing times, which are desirable in practice. But let short gel times little time to process the M; terials. d. i.e. the pot life is short. One is therefore scl · ,, in a long time striving to have long pot lives he / ielcn without inadmissibly extending the gel times. It is known from German Auslcgeschrift 1054 619, a solution of unsaturated Polyesters in monomers volatile inhibitors, / B. Oximes, add them as long as they are present Miid. prevent networking after processing the solution, for example, to paint layers. evaporate and then no longer inhibit the reaction. However, no inhibitors have yet been found which has been made for the requirements of the pia \ is evaporate quickly enough.

One also has by using such Initiators that do not yet form free radicals at room temperature, e.g. B. cumene hydroperoxide in combination with common activators, ready-to-use polyester solutions with long pot lives produced, whose reaction only starts when heated. However, the procedure is for those polyesters that are in Contact with the oxygen in the air, sticky top layers and which must therefore be processed according to German Pativiischnft 948 816, not applicable because the / ueeset / th protective substances e.g. paraffins that are completely or remain partially dissolved and therefore the protective layer ZL, r Voihinciciuiif .. the SauerMofT ..- in * 111 um: not more is enough or ubemaupi not ciiuκΊπ

Hs is also an attempt; been, ur- PmHe ir. drr 21: short Ί opi / .cheii dachrvh zu urn, iicti. that the li'iiiialo;"dorl'ulu'sie;'uü;: nii 1 ··. 'uiii'.'- i ■ ::. '• end him getreiin: on ciie /.u iacku' - ^ c Γ: ιΐ; ii.iij. au 'brings. According to the German .-V ^ U: ■ -vehriii i 0Π5 "?"'." the initialoi becomes a \ eih:: M: -n; .i! ^! ii; ' · .Ö; j> o:

medium is not polyester. This varnish is applied in a thin layer and after it has dried with: a layer of initiator-free. but containing activator: covered with polyester varnish. The reaction of the The polyester layer begins at the interface between the two lacquers and continues through the polyester layer through away. In this process it forms between the base and the polyester layer an optically different layer, so that ζ. B. a coating applied to high-grade resin veneers is not produces the same luminosity of the grain as a polyester lacquer, in which the wood fiber itself is embedded.

From US Pat. No. 2,890,193 it is known to add aromatic ketones to polyester resins, including those which carry OH groups, that is to say come close to benzoin. In the case of the ketol specified in the USA patent as a light stabilizer, the oxygen atoms, on the one hand, and the OH group, on the other hand, are not located on neighboring carbons, and the OH group is also aromatically bonded. Compounds of this type have not been found useful for the purposes of the present invention. The invention is based on the object of overcoming the disadvantages of the known coating compositions; The invention is based in particular on the object, in the case of polyester resin mixtures intended for the production of coating compositions, which are curable in the cold under the influence of ultra-violet light and which consist of styrene and a curable polyester composed of a ^ -unsaturated dicarboxylic acid and a dihydric alcohol, both to enable a very long pot life as well as a short gel time and thus rapid curing.
The subject matter of the invention is a polyester resin mixture, curable in the cold under the influence of ultra-violet light, for the production of coatings, consisting of styrene and a curable polyester from a \, / 3-unsaturated dicarboxylic acid and a dihydric alcohol, which is characterized by _{{ ()} , _to ^ _{based on the} mixture, of an activator of the formulas

_QC j _er

O X

q q

K ₁ -L - L. 1

_{in wekhen} χ _{Clivn Hydroxyrcsi} . an esterified or etherified hydroxyres'. R _{1 is} a phenyl radical and R is a phenyl radical. a "-Chlorphenvl-, o-Methoxyphenvl or p-Meihoxvphenyirest means, and '

^{i cint> Suchc Mcn} ß ^{e cincs} Vanadylacciaiv or ^{ς; ni} ' ^s ° ^{clMts odcr} Naphthcnats d, s L-isens. Koball «.. Manganese. Nickel"; «The chromium, dab dac Me-alka: / m cmr

j
poor, ciüiiiil'ussiüen lacquer / ui: e ^ et / t. whose limde-Ηο!> ρ ^ 'ι: such Ak'^; ^.: | iü. '^; : are benzoin. Ü; ■; ■ ,. : like, meli der: ¹ :: Sub ^ \ ii 1-1 .'PM't.nHik; and I'm wv .. ν V) da ¹ · 4.4'-DiCiIHi! ¹ '-1 /' Vn. da ¹ -. ".r'-Dinieth / iw i'-en / iii'i and the 4.4 ' ¹ InIiM']. ixybeii; .up. hum. ci 'l'sicr iiiui Viii ei d. ' Ren. 'i> i! ie.

Of the activators, based on the resin mixture, preferably 0.8 to 2.5% are used.

The metal salts are preferably used in an amount that, based on the resin mixture, 0.00001 to 0.01%, preferably 0.0003 to 0.001% iron or 0.005 to 0.25%, preferably 0.025 to 0.1% manganese are present.

The polyester resin of the invention may also contain thixotropic agents.

The polyester resin mixture according to the invention has a very long pot life and a short gel time a fast curing achieved in the production of coatings, since the crosslinking reaction with Room temperature by irradiating the coating with short-wave light, the wavelengths of which are predominant or are to a large extent in the ultraviolet, can be triggered for a short time.

example 1

10

55 parts of an unsaturated polyester prepared from 1 mole of phthalic anhydride, 2.2 moles of propanediol (1,2) and stabilized with 0.02% of hydroquinone were dissolved in 45 parts of styrene. 0.08 part of paraffin was added to the solution. 100 parts of this »5 polyester solution were mixed with 5.25 parts of a warm solution of 2 parts of benzoin in 5 parts of methanol and with 10 parts of a saturated solution of vanadyl acetate in methanol. This mixture contained 0.0096% vanadium and its pot life was 4 hours. The mixture was sprayed onto a wooden panel in a layer thickness of about ¹ A mm and irradiated with light with a wavelength of 254 mm, generated by a low-pressure UV lamp of 30 W, from a distance of 25 cm. The coating layer gelled in 6 to 12 minutes and was fully cured after a total of 20 minutes and was sandable after 40 minutes.

Example 2

80 parts of a commercially available polyester solution with a content of 65% unsaturated polyester and 35 ° ρ styrene were styrene with 11.4 parts, 1.6 parts a 5% paraffin solution in styrene and a warm solution of 2 parts of benzoin in 5 parts Methanol mixed. 100 parts of this mixture were mixed with 0.2 parts of a 10% solution of iron naphthenate in styrene - corresponding to 0.0012 parts of Fe - added. The pot life of this Mixing was about 3 days, the gel time after processing and exposure according to Example 1 was 7 to 18 minutes, curing was complete after 40 minutes, sandability after 80 to 100 minutes achieved.

Example! 3

85 parts of a solution of a commercially available unsaturated air-drying polyester resin with a Contains 60 "/ 0 unsaturated polyester and 410% styrene were mixed with 10 parts of styrene, 2 parts of 1% silicone oil solution in toluene and one Part of benzoin mixed in 2 parts of dispersant. 0.8 part of a 1% solution of iron naphthenate was added to this polyester resin solution (Fe metal content 0.00048%). ~

One of these in the usual way, but without additions Varnish or film made from peroxide was about −1 mm thick after exposure with a 2600 W high pressure mercury steam jet Can be sanded in 10 minutes. The Koenig pendulum hardness value was about 70 seconds after exposure.

A test carried out in the same way without the addition of iron only gave a pendulum hardness value of 20 seconds.

Example 4

100 parts of a benzoin-containing polyester resin solution composed according to Example 3 were used with 1 part of a 25% manganese naphthenate solution in styrene (Mn metal content 0.025%).

^{A coating or film of about 3} Λ mm thickness produced from this in the usual way, but without the addition of peroxide, was cured in 10 minutes. The König pendulum hardness value was then about 40 seconds.

A test carried out in the same way without the addition of manganese only gave a pendulum hardness value of 20 seconds.

Example

100 parts of a paraffin-containing polyester solution according to Example 1 were mixed with a warm solution of 2 parts of benzoin methyl ether dissolved in 5 parts of ethanol mixed. To 100 parts of this mixture 0.2 parts of a 10% solution of iron naphthenate in styrene - corresponding to 0.0012 parts Fe - added. The pot life of this mixture was about 6 days. A film about 0.5 mm thick was cured after exposure as in Example 3 after 12 to 14 minutes.

Example 6

100 parts of a paraffin-containing polyester solution according to Example 1 were with a warm Solution of 2.5 parts of benzoin acetate dissolved in 5 parts of ethanol mixed. To 100 parts of this mixture were 0.5 parts of a 6% solution of iron naphthenate in styrene - accordingly 0.003 part Fe - added. A film about 0.35 mm thick was cured as in Example 3 and then had a König pendulum hardness value of about 70 seconds.

Example 7

100 parts of a solution of a commercially available air-drying polyester resin were mixed with 5 parts Styrene and a solution of 1 part 4,4'-dichlorobenzoin in 5 parts ethanol and a few drops mixed alcoholic potassium hydroxide solution. To this mixture was added 0.5 parts of a solution of manganese naphthenate in toluene - corresponding to an Mn metal content from 0.025 »/ 0 - added. The pot row of the Mixture was about 2 days. The gel time under the action of a UV lamp of the Heraeus type NN 30'89 was about 10 minutes, and full hardening occurred after about 25 minutes.

Example 8

100 parts of a paraffin-containing polyester solution according to Example 1 was with a warm A solution of 2 parts of 2,2'-dimoxybenzoin in 8 parts of methanol is added. This mixture were 0.2 parts of a 10% solution of Eisennaphlhcnu; in styrene - corresponding to 0.0012 parts ferrous metal content - added. The pot life of this Wed.-.- huni:

was about 6 days. A layer of about 0.5 mm was, as in Example 3, exposed approximately Cured for 20 minutes.

Example 9

100 parts of a paraffin-containing polyester solution according to Example 1 were mixed with a paraffin-containing solution of 1.5 parts of 4,4-dimethoxybenzoin in 6 parts of ethanol. To this mixture was added 0.5 parts of a 6 ^f 'intrinsically solution of iron naphthenate in styrene - corresponding to 0.003 part of ferrous metal content - was added. The pot life of this mixture was about 8 days. A layer of about 0.5 mm was exposed as in Example 3, cured in about 15 minutes.

Example 10

100 parts of an unsaturated polyester prepared according to Example 1 are mixed with 20 parts of an ao 10% benzene solution mixed in styrene. To this The mixture is 0.2 parts of a 10% solution of iron naphthenate in styrene - corresponding to 0.0012 parts of Fe - added. The product has a Shelf life of 2 to 4 days. After processing and exposure as in Example 1, the gel time is about 20 minutes, and curing is complete after about 60 minutes.

Claims (1)

Claim: Polyester resin mixture curable in the cold under the influence of ultraviolet light for the production of coatings, consisting of styrene and a curable polyester from a ν / ^ - unsaturated dicarboxylic acid and a dihydric alcohol, characterized by 1 0.1 to 3%, based on on the mixture, an activator of the formulas
OX R-C-CH-R
OO !! Il R, - C - C - Ri a ve ^r esterten or etherified hydroxyl radical, R ₁ is a phenyl radical and R is in which X is a hydroxyl radical a phenyl radical, a p-chlorophenyl, o-methoxyphenyl or p-methoxyphenyl, and
such an amount of a vanadyl acetate or an octoate or naphthenate of iron, cobalt, manganese, nickel or chromium that the metal salt is present in an amount, based on the resin mixture, of 0.00001 to 0.25% of the metal.