DE2521986A1 - COATING COMPOSITION CURABLE BY RADIATION - Google Patents

Description

DR. E. WIEGAND DIPL-iNG. W. NOBODY? R?

DR. M. KÖHLER DlPL.-iNG. C. GERNHARDT "^

MÖNCHEN HAMBURG

TELEPHONE: 555476 8000 MDNCHEN 2. 1 «· ^ ^? -i 1975

TELEGRAMS: KA R PATE NT MATH I LD CN STRASSE 12 TELEX: 529 068 KARPD

V.4-2270 / 75 Kd / hs

Mobil Oil Corporation
New York, NY (V.3t.A.)

Radiation curable composite composition

The invention relates to radiation curable surfactant compositions based on Epoxy acrylate esters.

In British Patent 1,241,851, there is a Process for coating objects described in which a film of an ethically unsaturated ester is applied with hydroxyl groups and this one exposed to ionizing radiation. No liquid carrier is used.

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Similar resins are used in a carrier in the superior combinations according to the invention, which is a reactive monomer, This one Bearer reacts,>; erm die überaug3zuyai: .meiiaet.; Mig b & - S'branIt and göhär:; efc vnrd, mit- your Earx and: - / lrd a integral part of the resulting coating.

Heretofore, substrates such as metals that are suitable for making containers have been made with various Coating compositions similar to that heat bear cbai-e resin constituents and non-reactive, contained volatile organic solvents, wherein the solvents from the coating during carving removed. Today's restrictions on air pollution, the lack of organic solvents and the lack of fuel to heat the furnace required for curing has led to the desire for coating compositions which are low energy cured can and where non-reactive organic solvents are not required.

In accordance with the invention, radiation curable coating compositions are provided which are composed of an adduct of acrylic acid and an epoxy resin or an adduct modified with an anhydride and which are characterized in that they contain a reactive acrylate monomer.

When curing with ultraviolet light (UV light), photosensitizatoiai and a tertiary Amine used as a cosensitizer.

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There are also pigmented ones that are curable with UV light Coating compositions have been created that contain a photo-sensitizer combination from 2-chlorothioxanthone and a phenyl ketone.

UV-curable coating compositions are also grounded with improved adhesion in which at least a portion of the tertiary amine cosensitizer is created Dimethylaminoäthylacrylat is replaced.

The coating compositions according to the invention include an adduct, a reactive monomer carrier, and optionally a photosensitizer. The adduct is an adduct of acrylic acid and an epoxy resin. This adduct can be modified by reacting with an anhydride be.

The epoxy resin can be any of the polyglycidyl ethers polyhydric organic compounds, especially polyhydric phenols. Glycidyl ethers are particularly important Preferred by bisphenols, the two phenolic groups that dirch an intervening aliphatic bridge are connected.

Although any bisphenols can be used, the compound 2.2-bis (p-hydroxyphenyl) propane, commonly known as bisphenol A, which is the most readily available commercially. Of the suitable Diglycidyl ether is preferred over polyglycidyl ethers.

Depending on whether the epoxy resin is essentially monomeric or in certain. AwimF'.l pojyineri-

fa O 9 8 A 9 / O 9 8 6

the preferred epoxy resins have an epoxy equivalent weight between about 170 and about 2000 and an epoxy value between about 0.60 and about 0.05 · Die preferred epoxy resins, that is, those made from bisphenol A, have two spoxy groups each Molecule. Hence the stoichiometric required Amount of acrylic acid to form a diacrylate adduct two moles of acid for every two epoxy groups. In the In practice, however, it is preferred to use slightly less acid than the amount necessary to keep with to react both epoxy groups, namely to ensure that no free acrylic acid in the reaction product is present. Free acid would lead to increased volatility of the films formed, while small amounts bring no disadvantages to free epoxy groups. Because of this, the amount of acrylic acid used between about 1.85 and 2.0 moles of acid for every two epoxy groups. The esterification reaction between the acrylic acid and epoxy resin are at esterification temperature, e.g., between about 90 ° C and about 110 ° C carried out. The esterification is carried out until an acid number of 5 to 15 is obtained. This implementation usually takes 8 to 15 hours.

In a further embodiment according to the invention, the epoxy diacrylate is further reacted with an anhydride. Maleic anhydride is preferred. However, other anhydrides are also suitable for this purpose, such as citraconic anhydride, succinic anhydride, ethylsuccinic anhydride, amylene succinic anhydride, itaconic anhydride, glutaric anhydride, Λ -4-tetrahydrophthalic anhydride, phthalic anhydride,

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Hemimellitic anhydride, trimellitic anhydride and pyromellitic anhydride. The amount of anhydride used is between about 0.1 and 1.0 moles of anhydride per mole of diacrylate resin. The reaction is generally carried out at a temperature between about 80 ° and about 90 ⁰ C. The conversion is considered complete when the acid numbers determined with alcoholic EOH and aqueous KOH match, ie are about 10 to 40. This shows that anhydride groups are no longer present.

The esterification reaction and the further reaction with anhydride can be carried out without a catalyst will. However, it is preferred to carry out these reactions with the aid of catalysts such as tertiary amines, quaternary ammonium hydroxides, such as benzyltrimethylammonium hydroxide, Ν, Ν-dimethylaniline, N, N-benzylmethylamine, Perform triethylamine and KOH. It is also advantageous to use small amounts of hydroquinone Use polymerization inhibitor.

The epoxy diacrylate prepared as described above or the anhydride modified epoxy diacrylate is then dissolved in a reactive monomer carrier to prepare the coating composition. The reactive monomer carrier is a monofunctional ester, acrylic acid with 4 to about 20 carbon atoms. The acrylate esters can be alkyl or hydroxyalkyl acrylates, such as methyl acrylate, Ä * thy I acrylate, hydroxyethyl acrylate, Propyl acrylate, isopropyl acrylate, hydroxypropyl acrylate, butyl acrylate, isobutyl acrylate, Amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, Decyl acrylate, dodecyl acrylate, tetradecyl acrylate

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and hexadecyl acrylate. Acrylic esters of the ether alcohols of the formula ROCEUCHpOH, in which R is an alkyl group with 1 to 6 carbon atoms or a phenyl group, ie cellosolves, are also suitable. Examples of such esters are methoxyethyl acrylate (methyl cellosolve acrylate), itoxyethyl acrylate (cellulose acrylate), butoxyethyl acrylate (butyl cellusol acrylate), isobutoxyethyl acrylate (isobutyl cellusol acrylate), hexoxyethyl acrylate (phenyl cellulose acrylate) and phenoxyethyl acrylate. The reactive monomer carriers. can be described with the formula CHp = CH _p COOR ', in which R ¹ denotes hydrogen, an alkyl group with 1 to 15 carbon atoms or a -C ^ H ^ OR "group, in which R" denotes an alkyl group with 1 to 6 carbon atoms or represents a phenyl group. The reactive monomer carrier may contain a small amount (up to about 20% by weight) of a multifunctional acrylate, for example neopentyl glycoid diacrylate, but is essentially monofunctional.

The coating composition is cured by exposure to radiation. When the radiation used is electron beam, no photosensitizer is required, but when ultraviolet light is used, a photosensitizer is required. Suitable sensitizers are acetophenone, benzophenone, zanthone, benzoin isobutyl ether and 2-chlorothioxanthone. 2-chlorothioxanthone is preferred, especially when the formulation is provided with pigments. A tertiary amine cosensitizer can be used in UV-curable coating compositions and serves to accelerate the rate of cure. To achieve this effect

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aim, it is necessary that free amine is present. The amine concentration is usually in the range between about 1.25 to about 3 times the kenge required is to neutralize the free acid. The amount required for neutralization can easily be calculated from the specific acid number of the resin. The tertiary amines are usually liquid trialkylamines, trialkanolamines or tertiary mixed alkylalkanolamines. Examples of such amines are triethylamine, triisopropylamine, tributylamine, trihexylamine, tri-2-ethylhexylamine, Tridodecylamine, methyl diethanolamine, dimethylethanolamine, 2-hydroxyethyldiisopropylamine and triethanolamine.

The coating compositions according to the invention form and are in clear coatings Form applicable.

Although a pigment is not required, it is preferred to include a pigment in the coating compositions to be introduced according to the invention. The preferred pigment for white coatings is titanium dioxide. However, all known filler pigments can be used, such as zinc oxide, ^ bentonite, silicon oxide, ocher and Chrome yellow and chrome green.

Depending on whether the coating compositions are pigmented or non-pigmented, Table I below shows the suitable and preferred concentration ranges of the ingredients specified.

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Table I.

5098 ^ Components suitable (Wt%) 10-75 preferred (Wt%) CD Adduct resin pigmented not pigmented 20-90 pigmented not pigmented - ⁴ ^
CD
CD Reactive monomer
carrier 10-30 0.5-6 15-30 10-50 CO
CD tertiary amine 40-60 0.1-2 30-50 50-90 Sensitizer
(if used) 0.5-6 2-4 2-4 0.1-2 0.5-1 0.5-1

The coating compositions are applied to conventional substrates such as metal, paper, leather, cloth and the like. applied using any conventional method of application such as brushing, spraying and Application by means of rollers. Suitable metallic substrates are aluminum, steel and galvanized steel. It is sufficient to use the coating in an amount of

apply about 1 to 20 mg / 6.4 cm. After application, the coating is cured by exposure to radiation for about 0.01 to about 30 seconds. In some cases, the coating with a short irradiation, for example, cures less than 1 second ₅ so that the coating colors and / or Naßfarblacke assumes. After printing, or to providing coatings with these coatings may be further cured by being heated to about 5 minutes to 121.1 2 $ 2 ° C (250 to 450 ⁰ F) for about 3 seconds.

Suitable radiations are ultraviolet light and electron beams. Ultraviolet is preferred Light of a wavelength less than 4000 Angstrom units. The electron beam is formed by high-energy electrons that are generated with a high-voltage electron accelerator be generated. Such devices are well known and include VandeGraaff's accelerator, resonance transformer, Transformer rectifier, microwave waveguide linear accelerator and synchrotrons.

The preparation of the adducts and the coating compositions according to the invention is described below explained in more detail using examples.

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example 1

In a vessel equipped with a stirrer, a reflux condenser, an inlet for inert gas and a charging device, 660 g of a diglycidyl ether of bisphenol A with a spoxy equivalent weight of about 185 to 192 and an epoxy value of 0.50 to 0.54- (Epon 828) brought in. Nitrogen was introduced through the gas inlet throughout the resin production. With stirring, 2p8 g of ice-cold acrylic acid were added and the mixture was stirred until the epoxy resin was dissolved. After the acrylic acid had dissolved, 1.3 S triethylamine and 0.1 g of hydroquinone were added. With further stirring, the temperature to about 96.1 ⁰ C to 100 ⁰ C (205-212 ⁰ F) and maintained at this value until the acid number was about 5 to 10 (about 10 hours). The temperature was reduced to about 65.6 ⁰ C to 71.1 ° C (I50 to 16O ⁰ P), and 600 g of hydroxypropyl acrylate were added, and the mixture stirred until uniform. The end product was a clear solution of the prepolymer in the monomer at a weight ratio of 60 / 4-0.

Example 2

7,200 g of diglycidyl ether of bisphenol A, 2590 g of ice-cold acrylic acid, 15 g of triethylamine and 1.2 g of hydroquinone were placed in a vessel which was equipped as described in Example 1. The mixture was stirred while introducing nitrogen and the mixture was heated to 100.degree. The temperature was maintained at 95 ° C to 100 ⁰ C, until an acid number of 5 to 10 Then 432 g of maleic anhydride were added and the temperature was kept at 90 ° C until the with alcoholic KOH and

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aqueous KOH agreed acid number, indicating the complete absence of anhydride. The time typically required for this resin preparation step is 1 1/2 hours. Then 6,835 g of hydroxypropyl acrylate were added. The end product had a weight ratio of prepolymer / monomer of 40/60, a viscosity of 850 to 900 cP at 26.7 ° C. (80 ⁰ I ¹ ), a ratio of 4.3 kg / 3.8 1 and an acid number from 28 to 35 · The molar ratio of maleic anhydride to epoxy resin was 0.25-

The following examples 3 and 4 relate to coatings, which can be hardened by electron beams.

Example 3

In a suitable size high speed disperser, there was 12.29 kg (27.1 lbs) of product of Example 1 and 1914 kg (42.8 lbs) of titanium dioxide pigment intimately mixed and the mixture stirred until a freeness of 7 or better was achieved. Then 14.2 kg (31 »*! bs) hydroxypropyl acrylate and 9.16 kg (20.2 lbs) of the product of Example 1 was added and the mixture stirred until uniform. The product obtained had a pigment / binder ratio of 0.52 / 1 and a ratio of prepolymer to total binder of 0.4 / 1.

Example 4

"Using the apparatus of Example 3 12.4 kg (27.3 lbs) of the resin solution of Example 2 and 19.15 kg (42.9 lbs) of titanium dioxide pigment were intimately mixed.

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Then it was stirred at high speed, until a minimum meal of 7 has been reached. The stirring was continued at a slower speed, being 4.54 kg (10.0 lbs) of the resin solution of Example 2 and 7.94 kg (17.5 lbs) of hydroxypropyl acrylate were added. This mixture was stirred until uniform. The product obtained had a pigment / binder ratio of 0.78 / 1 and a ratio of prepolymer to total binder of 0.4 / 1.

Example 5

A suitable size ball mill weighed 0.45 kg Introduced 2-chlorothioxanthone and 0.9 kg of hydroxypropyl acrylate. This mixture was milled for 24 hours until it was thoroughly dispersed. The product is used as a photoinitiator suitable for pigmented coatings.

Example 6

In a suitably sized high speed disperser, 12.3 kg (27.1 lbs) of the product were obtained of Example 1, 19.4 kg (42.8 lbs) titanium dioxide pigment and 0.7 kg (1.5 lbs) of the product of Example 5 intimately mixed. This mixture was stirred until a freeness of 7 or better was obtained. Then were 14.2 kg (31.4 lbs) of hydroxypropyl acrylate, 0.9 kg (2 lbs) of methyl diethanolamine, and 9.2 kg (20.2 lbs) of the product of Example 1 was added. The mixture was stirred until uniform. The coating obtained had a pigment / binder ratio of 0.52 / 1 and a ratio of prepolymer to total binder from 0.4 / 1.

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Example 7

Using the equipment of Example 6, 12.4 kg (27> 3 lbs) of the resin solution of Example 2, 19 »5 kg (4-2.9 lbs) titanium dioxide pigment and 0.36 kg (0.8 lbs) 2-chlorothioxanthone intimately mixed. The honor under high speed was continued until a freeness of at least 7 was obtained. The stirring was then continued at a slower speed using 4, 5 kg (10 lbs) of the resin solution of Example 2, 7.9 kg (17.5 lbs) of hydroxypropyl acrylate and 0.68 kg (1.5 lbs)

Methyl diethanolamine were added. This mixture was stirred until uniform. The coating obtained had a pigment / binder ratio of 0.78 / 1 and a ratio of prepolymer to total binder of 0.4 / 1.

Examples 8 to 27

In Table II below, values are given for various coatings which were produced in accordance with the procedure described in Examples 1 to 7. Each coating was applied to different substrates, cured with UV light or electron beams and examined for its properties. The adhesion test is performed by hatching a coated area with cut lines about 0.16 cm (1/16 inch) apart and pressing an adhesive strip firmly onto this hatched area and quickly removing it. The amount of coating remaining on the panel was visually determined and determined on a percentage basis. Pasteurization was performed by immersing the coated plate in water at 69 ° C (155 ° F) for 30 minutes. Then the

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Ik.

- Vi- -

The panels were wiped dry with an absorbent cloth and the adhesion test was carried out as described above.

The following abbreviations are used in Table II:

THP CTX Monomer trv-25

= Epon 1004; reaction product of epichlorohydrin and bisphenol A, molecular weight about 1400, epoxy value 0.10 to 0.12

= Epon 828; Diglycidyl ether of bisphenol A, Molecular weight about 350 to 400, epoxy value 0.50 to 0.54

= 2 moles of acrylic acid, per mole of epoxy = 0.25 moles of maleic anhydride per mole of epoxy = hydroxypropyl acrylate - hydroxyethyl acrylate = 2-ethylhexyl acrylate = methyl diethanolamine = triethanolamine = centipoise = aluminum = chromium-chromium oxide-treated steel a tin-coated steel Fr.

= Titanium dioxide = <^ - 4-tetrahydrophthalic anhydride = 2-chlorothioxane bon = reactive monomer carrier

= Ultraviolet light at a linear velocity of 7.62 m (25 ft) / min per lamp

s * electron radiation of 2 Me even ad

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Table II Viscosity, adhesion, gloss and feathering at different values of the epoxy molecular weight

and anhydride

Composition % by weight resin monomer

CD
CO
CO
OT

Example Type% by weight Type% by weight

8 828 / A / M 23.O HPA

9 828 / A / M 23.2 HPA

10 828 / A / M 42 KPA

11 828 / A / M 44 HPA

12 828 / A 22.8 HPA

13 828 / A 23-2 HPA

14 8? 8 / A 53 HPA

15 828 / A 45 HPA

16 1004 / A / M 20 HPA

17 1004 / A / M 20 HPA

18 1004 / A / M 30 HPA IQ LOOVA / M 30 HPA

20 1004 / A 20 HPA

21 1004 / A 20 HPA

22 1004 / A 30 HPA

23 1004 / A 30 HPA

24 828 / A 23.2 HEA

25 828 / A 28.6 HPA

26 828 / A / M 23.O HPA /

2-EH A

27 828 / A / THP 23.2 HPA

29.7 34.8

56

44 * 55

Amines

Viscosity (cps) at shear rate

41.7 33.3 46.7 33.3 66.5 70 _ 42.2 33.3 46 7 33.3 66 ^ 5 - 70 _ 30.3 42 25.6 42 14.6 / 42 14.6 30.3 37

Weight% Type Weight%

MDEOA
MDEOA
MDEOA
MDEOA
MDEOA
MDEOA
MDEOA
MDEOA

MDEOA

TEOA

MDEOA

.5 MDEOA

4 4 4
2
4th

4th
2

222 sec '

615 6OO 200 250

375

4oo

200

150 iooo 1200

400

500

9OO

900

350

450

500 1200

67O

244

0.0028 see

18,000

10,000

200

3OO

29,000

60,000

3OO

200

2,460

4,000

400

600

15,000

45,000

350

550

35,000

60,000

156,000

24,000

CD OO CD

Table II (continued)

Viscosity, adhesion, gloss and flow at different values of the epoxy molecular weight

and anhydride

Film properties

JJ \ 5 JU O ^ /. Hardening 8th conditions 9 UV-25 10 EB-2 cn 11 UV-25 σ 12th EB-2 CD 13th UV-25 co 14th EB-2 , "A 15th UV-25 16 EB-2 CD . 17th UV-25 CO 18th EB-2 CO 19th UV-25 CD 20th EB-2 21 UV-25 22nd EB-2 23 UV-25 24 EB-2 25th UV-25 26th UV-25 27 UV-25 UV-25

% Adhesion after % adhesion after
5-min. Heating pasteurization
to 177 ⁰ C (35Q ⁰ J?)

Al CCO CDC5 Al CCO CI

100 100 25th 100 100 0 100 100 25th 100 100 0 100 0 0 100 0 0 100 0 0 100 0 0 100 0 0 100 0 0 100 0 0 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 100 100 100 100 50 100 100 100 100 100 50 100 100 . 100 100 100 0 100 100 100 100 100 0 100 100 0 100 100 0 100 100 0 100 100 0 100 0 0 100 0 0 100 0 0 100 0 0 100 100 25th 100 100 0 100 100 25th 100 100 0 100 100 100 100 100 0 100 100 100 100 50 0

Shine run

30 90 80

95 50

90 80

6o 90 80 90 55 90 80 90 55 65 15 60

good Good

excellent excellent bad badly marked. excellent excellent _% excellent - * excellent ^ * excellent acceptably acceptably priced. excellent reasonably good

acceptbu-r tvj

acceptable- cn

The results given in Table I show the following:

(a) An increase in the molecular weight of the epoxy resin improves the adhesion to metals

(b) Maleic anhydride adducts show better adhesion to metals and better flow as compositions of resins without maleic anhydride

(c) Coatings with a content of TiOp show better adhesion to metals than identical coatings without TiO ₂ ♦

The coating compositions described above can be viewed as "base coating compositions". It has been found that certain properties of the cured films are improved by the incorporation of further chemical compounds in these basecoat compositions can significantly improve the properties of the cured films.

In the case of the UV light curable basecoat compositions, the gloss of the cured film is generally lower than desired, especially at high cure speeds. This shine can, through use a coating composition comprising a mixture of sensitizers of 2-chlorothioxanthone and a phenyl ketone, can be significantly improved. Benzophenone is that preferred phenyl ketone, but other phenyl ketones such as acetophenone, propiophenone and butyrophenone, be used.

This improvement in gloss is shown in the following examples. In each example, according to the in Examples 1 to 7 described a procedure

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pigmented coating composition (A) without benzophenone (Bzph) and (B) made with benzophenone, and these applied to aluminum and treated with UV light exposed at different curing speeds. The obtained films were glossy at 60 ° examined.

Example 28

An epoxy diacrylate of a diglycidyl ether of bisphenol A (Epon 828) was modified with 0.25 moles of maleic anhydride per mole of epoxy. This resin (resin A) was mixed with hydroxypropyl acrylate, TiO ^ pigment and sensitizer and cosensitizer. Below
the amounts of the constituents, the pigment / binder ratio (P / B), the resin / binder ratio (R / B) and essential test results are shown.

Examples TiO ₂ GTX (25FPM) MDEOA no resin A. 5 2% Bzpl 28A 36.6 0.9 yield 3.6 24, 5 28B 36.6 0.9 shine 3.6 24, 90 Examples HPA BZJDh. P / B R / B 88 28A 34.4 0 0.58 0.39 28B 32.4 2.0 0.58 90 0.39 UV curing speed 79 J3zph 7.62 m / min

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Example 29

An epoxy diacrylate of a diglycidyl ether of bisphenol A (resin B) was _{mixed with hydroxypropyl acrylate (TiO 2} pigment) and sensitizer and gosensitizer. The amounts of the constituents and essential test results are given below.

example TiO ₂ Resin B HPA CTX 29A 42.8 28.6 25.6 1.0 29B 41.5 27.7 24.8 1.0 example MDEQA Bzph P / B R / B 29A 2.0 0 0.75 0.50 29B 3.0 2.0 0.71 0.475

UV curing speed

m / min (PPM) yield no Bzph 2% BzT> h 7.62 25th shine 94 91 yield 95 95 15.24 50 shine 91 87 yield 77 93 $ 0.48 100 shine 87 84 Example 30 39 90

An epoxy diacrylate of 1004 was modified with 0.25 moles of maleic anhydride per mole of epoxy. This resin

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(Resin C) was made with hydroxypropyl acrylate, TiOp pigment and sensitizer and co-sensitizer mixed. The following are amounts of the components and essentials Test values given.

Examples TiO ₂ resin C (PPM) 1 no CTZ 2% Bzph 3OA 33.3 20.0 25 yield 1.0 3OB 33.0 19.8 shine 88 1.0 88 Examples EDEOA HPA 50 yield 89 Bzph 89 3OA 4.0 41.7 shine 86 0 85 3OB 4.0 41.2 100 yield 7 "? , 0 88 UV curing speed shine 73 Bzph 77 m / min 45 62 7.62 15.24 30.48

The preceding examples show that the phenyl ketone benzophenone in combination with 2-chlorothioxanthone has essentially no effect on film yield, but has the gloss of pigmented UV curable coatings increased. Each sensitizer is used as described in an amount from about 0.1 to about 2% by weight used.

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It has been found that the adhesion of the cured coatings to certain substrates, in particular pasteurized adhesion (hereinafter abbreviated to past. Adh.), by using dimethylaminoethyl acrylate (DMAEA) in the coating composition is improved. For electron beam curable coatings, the DMAEA is used in the coating composition in amounts between about 0.5 and about 6% by weight are added. For UV-curable coatings the DMAEA in amounts between about 0.5 and about 6 wt .-% instead of all or part of the tertiary amine cosensitizer used.

Example 31

Resin B (Example 29) was mixed with hydroxypropyl acrylate, 2-chlorothioxanthone and MDEOA or DMAEA. The coatings were applied to aluminum plates and cured with UV light. The coated panels were the Subjected to adhesion test. The amounts of the ingredients and the test results are shown below.

Examples Resin B CTX HPA MDEOA DMAEA 31A 4-9.5 1.0 44.5 0 5 31B 50.0 1.0 47.0 2 0 UV curing (15 , 24 m / min; 50 PPM) Movie example yield adhesion Past. Adh. 31A 92 100 50 31B 89 20th 0

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■ oU ·

Example 32

Resin C (Example 30) was made with hydroxypropyl acrylate 2-chlorothioxanthone and MDEOA or DMAEA. mixed. the Coatings were applied to aluminum panels and UV cured. The coated panels were re the adhesion investigated. The amounts of the ingredients and the test results are shown below.

example Resin C HPA πι / min GTX MDEOA DMAEA Past. 32A 29.2 68.2 0.5 2 0 Adh. 32B 29.2 68.2 0.5 0 2 85 example UV curing Movie- 70 speed (FPK) yield Adh. 100 32A 7.62 25th 92 100 100 15.24 50 87 100 32B 7.62 25th 89 100 15.24 50 87 100 Example 33

Resin B (Example 29) was _{mixed with hydroxypropyl acrylate, TiO 2} pigment, 1.0% 2-chlorothioxanthone and MDEOA or DMAFA. The pigment / binder ratio of the coatings was 0.75 and the ratio of resin to total binder was 0.40. Each coating was applied to metal plates and cured with UV light. The coated panels were examined for adhesion. The results are given below.

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Amine viscosity Example 34 cP 0
100 Examples 4% MDE0A
5% DMAEA 222 see- ¹ 0. 33A
33B 395
283 Examples 15.24 m / min (50 PPM)
yield 33B 00 00
vD VD , 0228 see " ¹ 29 100
564 Adhesion to
Al CCO 100
100

Resin B (Example 29) was _{mixed with hydroxypropyl acrylate, TiO 2} pigment, 1.0% 2-chlorothioxanthone and MDEOA or DMAEA. The pigment / binder ratio of the coatings was 0.75 and the resin / binder ratio was 0.6. The coatings were applied to metal plates and UV cured. The coated panels were examined for adhesion. The results are given below.

Examples amine

4% MDEOA 5% DMAEA

222 se e

800 598

-1

0.0228 see

86 100 14 800

-1

Examples

15.24 m / min (50 PPM) yield

Adhesion to Al CCO

88 89

100
100

0 100

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From the above examples it can be seen that
the use of dimethylaminoethyl acrylate results in at least equivalent UV curing. It also leads to improved adhesion both in the wet and in the dry state.

The examples below show preferred coatings compositions according to the invention.

Example 35

Using a reaction vessel equipped with a stirrer, reflux condenser, inert gas inlet and feeder, 525 g of the reaction product of epichlorohydrin and bisphenol A and 70 g of toluene were charged. It was heated, stirred and a slower inert gas stream was introduced. The temperature was increased to reflux temperature to remove the water (vessel temperature 150 to 160 ° C). The mixture was cooled to 80 to 85 ° C. and 4-0 g of ice-cold acrylic acid, 1 g of triethylamine and 0.1 g of hydroquinone were added. The temperature was raised to 95-100 ° C to achieve esterification and the reaction continued until an acid number of 8-13 was obtained. The mixture was then cooled to 80 to 85 ° C. and 7 g of maleic anhydride were added. The temperature was kept at 80 to 85 ^° C. for 1 1/2 to 2 hours until the acid numbers determined with alcoholic KOH and aqueous KOH matched (10 to 15). The heat source was removed and 175 S hydroxypropyl acrylate was added. The mixture was heated again to 80-85 ° C and vacuum applied to remove the toluene. The heat source was then removed and a further 182 g of hydroxypropyl acrylate were removed

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admitted. The final product had a viscosity of 45 to 50,000 cP, a ratio of 4.35 kg / 3.8 1, one Acid number of 10.5 and a solids content of about 97% · This resin was used for the formulations of the examples 36 to 38 used (the amounts are in% by weight specified).

Examples 36 to 38 Clear coatings

Components 36 37 38

Composition according to
Example 35 40.3 56.4 33.2 Hydroxypropyl acrylate 56.3 40.2 37.6 Pbenyl cellosolve acrylate - - 21.8 Methyl diethanolamine 1.9 1.9 2.9 Dimethylaminoethyl
acrylate _ _ - 3.5 2-chlorothioxanthone 0.5 0.5 0.5

Fluorocarbon

Wetting agent - - 0.5

Silicone lubricant 1.0 1.0 viscosity (seconds

No. 4 Ford Cup) 50-60 175-225 30-35

kg / 3.8 1 4.10 4.26 4.06

(Wt./gal. (Ib.)) (9.04) (9.40) (8.95)

Examples 36 and 37 show abrasion resistant coatings for bottoms of cans that have been applied by brushing and one to two seconds with UV power treated with no post-curing required.

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* ■ .26 -

Example 38 shows a coating for flat sheets or webs and may be applied with rollers, one second with UV light is irradiated and cured in the oven, for 10 minutes at 171-204 ° C (340 to 400 ⁰ F). The phenyl cellosolve acrylate in Example 38 gives the coating improved corrosion resistance and flexibility.

Example 39

In a suitable size ball mill, 312 g an epoxy diacrylate made from diglycidyl ether of bisphenol A and acrylic acid, 430 g titanium dioxide, 198 g cellosolve acrylate, 10 g 2-chlorothioxanthone, 40 g Dimethylaminoäthylacrylat and 10 g of benzophenone introduced and to a grind of 7, measured on a Hegman grind meter, ground. The meal lasted 24 to 48 hours. The end product was a white coating composition, which was suitable for application with rollers on flat plates or webs. The product had a viscosity from 90 to 100 sec No. 4 Ford Cup and weighing 5.9 to 6.0 kg (13.1 to 13.3 lbs) each 3.8 1. It will normally applied at a thickness of 10 mg / 6.4 cm and cured by irradiating with UV light for one second and then cured for 6 minutes at 163 ° C (325 ° F) will. After UV exposure, the film was sufficiently cured to accept paints and wet paints. The 6-minute curing at 163 ° C was carried out after the dyeing or painting.

In Examples 38 and 39, methylaminoethyl acrylate was used used. This compound has a tertiary amine functionality. It can therefore, as above executed the tertiary amine, which is used to increase the

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Cure rate used is replaced partially (Example 38) or entirely (Example 39). This compound also shows a reactive ethylenically unsaturated functionality (acrylate) and is therefore effective as a reactive monomer. The use leads to a coating composition with improved rheology, this is reflected in better flow properties and the cured coatings have improved adhesion to metal substrates. The addition of benzophenone to the coating composition (Example 39) improved the gloss of the pigmented coatings.

Other known auxiliaries, such as flow regulators and waxes, can be added to the coatings. Using of waxes these are called slurries or emulsions of petroleum wax (paraffin wax), natural waxes such as montan wax, beeswax and carnauba wax, synthetic waxes such as polyethylene wax are added.

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Claims (9)

Claims Λ . Radiation-curable coating composition consisting of an adduct of acrylic acid and an epoxy resin which can be modified with an anhydride, characterized in that the composition contains a monofunctional acrylic acid ester as a carrier. 2. Coating composition according to claim 1, characterized in that the ester is hydroxypropyl acrylate. 3. coating composition according to claim 1, characterized characterized in that the ester is hydroxyethyl acrylate. 4. A coating composition according to any one of claims 1 - 3i characterized in that it further comprises a photosensitizer and a tertiary amine as Cosensibili- sator. 5 · Coating composition according to claim 4, characterized characterized in that the photosensitizer is 2-chlorothioxanthone is. 6. coating composition according to claim 4 or 5i characterized in that the tertiary amine is methyl diethanolamine or triethanolamine. 7- coating composition according to any one of claims A- - 6, characterized in that it also contains dimethylaminoethyl acrylate contains. B. Coating composition according to any one of claims 1-7? characterized in that it is also a phenone, preferably benzophenone. 9 849/0986