AT527021A1 - Photobases - Google Patents

Abstract

The present invention relates to the use of a triphenylphosphonium carboxylate salt of the following formula (I) as a photobase generator in a photopolymerizable composition comprising at least one type of monomers for producing photopolymers by curing the composition by irradiation with light of a suitable wavelength: wherein R1 and R2 are each independently selected from -H and -OCH3, wherein on each of the three phenyl radicals at least one of R1 and R2 is -OCH3, and wherein R3 is selected from -H and -CH3 and X is either absent or selected from a chemical bond, -CH2-, -O-CH2- -CH2-O-, -C(=O)-, -O- and -S-; and corresponding novel triphenylphosphonium carboxylate salts of the formula (I).

Description

Photobase generators in phatepolymerizable compositions,

STATE OF THE ART

The concept of organic phenol base generators (FRG) was first introduced in 1900 by Cameron and Frechet, who used a hydroxyl-based carbamate group to generate basic amines (J.F. Cameron, JM... Frechet, J. Org. Chem. 55, 5919-5922 (1900). Later reports describe the induced release of primary, secondary or tertiary amines, which are rather weakly basic and therefore inefficient in the activation of anionic polymerization. The use of salts to generate bases first appeared in a report from 1598 in the form of quaternary ammonium salts (Sarker et al, 4, Phys, Chem, A 102, 5375-5382 (1998), which significantly increases the storage stability of the formulations, in recent years numerous Carboxylates are described as counterions of the bases in the salts used as PBG. For example, in one article, salts of 2(3-benzoylphenol, 2-xanthone-2-yl) and 2-thioxanthorne-2-ylpropionic acid or acetic acid are disclosed as carboxylate-functional chromophores for PBG. These are characterized by short-lived absorption wavelengths below 400 nm and are therefore suitable for curing the formulations using UV irradiation. The cations of the salts include those of peralkylated guanidines and phosphazenes (Zivic et al., Angew. Chem. Int. Ed, S8(31), 10410-40422 (2017-193).

Recently, the suitability of triphenylphosphines as nuciferous catalysts for oxa-Michael additions was also revealed, whereby specifically triphenylphosphine, mono- and trimethoxylated triphenylphosphine were investigated for their catalytic effect on 16 different combinations of Michael donors and acceptors. The use of tris(d-methyl-oxyphenylphosphine) tended to give the best conversions, but in almost half of the experiments hardly any differences could be observed between the three catalysts (Fischer et al, Selstein J. Orga. Chem 47, 1680-1607 (20273).

compositions,

DISCLOSURE OF THE INVENTION This object is achieved by the present invention in a first aspect by providing a new photopolymerization process, namely one using a triphenylmethane carboxylate salt of the following formula {PD} as a photobase generator in a photopolymerizable composition comprising at least one type of monomers for the preparation of photopolymers with partial curing of the composition by irradiation with light of a certain nmellar length:

1 7 2 LE y RR Rn | | a

} A EN 4 Kr ; |

} wherein RT and R% are each independently selected from -H and -OCHa, wherein on each of the three phenyl residues at least one of RT and R? is -OCMa, and wherein R3 is selected from -H and -CH3 and X is either absent or selected from a chemical bond, -CHa-, «CACHia- «CH2-Q-, -CI=C}, -5- and -5-.

The inventors have discovered that the salts consisting of such a triphenyl ohosohanlum cation and the amino acid of a phenylacetic acid or phenylpropionic acid derivative defined above, all of which were prepared for the first time by the inventors, are sometimes excellent photobase generalizers.

ran, as the later games clearly show, Möchst surprising was

De

have.

According to the invention, conversions were already achieved with singly methoxylated phenyl radicals, with the methoxy group in the ortho position, i.e. with an -OCHs as RR} giving better results than in the para position, i.e. with -OCHs as R*. However, the triphenylphosphonium cations with multiply methoxylated phenyl radicals were clearly superior to these. In preferred embodiments, therefore, at least one R' on each of the three phenyl radicals is -OCH3, even more preferably both R7 are -GOCH3, and in particular both R* and R° are -OCHs. This means that the phosphenium cation of the salt is preferably the tris(2-methoxyphenol)phosphonium, even more preferably the tris(2,6-dimethoxyphenol)phosphonium and

in particular the triis(2,4,8-yimethoxyphenyBohosphonium potassium ion,

As for the carboxylic anion, in preferred embodiments, X is absent or is selected from a chemical bond, -C- and -5-. More preferably, it is the anion of one of the following. Carboxylic acids: 243-benzoyiphenyÖpropionic acid (kefoprofen) or -acetic acid, 2-(xanthone-Z-vvibroprofen acid or -acetic acid or 2thioxanthone-2-vipropionic acid or -acetic acid, And in particular the photobase generator is selected from the following triphenylphosphonium carboxylate salts: tris(2,6-dimethaxyphenyiiphosphonium-Z-(I-benzoyiphenyÖproglonate, tris(2 4,5-trimethaxyohenyÜphosphonlium 2-(3-benzoylphenylpropionate, tris(2,6-dE methoxyphenyÜphosphonium-Z-(xanthone-2\Macetate, tris(2,4,8-wimethoxyphenyl)ohosphonium-2-xanthone-Z-yfacetate, Tris(2,6-dimeihoxyphenyllphosphonium-Z-{thioxanthone-Zacetate or Tris(2,4,6-trimethoxyophenyDphosphonium-Z-(hloxanthan-2-

yDacetate, with which excellent results were achieved.

The type of curing of the photopolymerizable composition is not specific

limited, In preferred embodiments, the photopolymerizable

However, the composition is either applied to a substrate and hardened to a coating by re-abrasion or hardened to a three-dimensional object in a generative manufacturing process by means of layer-by-layer irradiation. In both cases, the hardening can be carried out by heating and the photopolymer obtained can be subjected to a thermal post-treatment.

to optimize the mechanical properties.

As a generative manufacturing process, hot laeography is preferably used with heating to a temperature of at least 50 °C or at least 70 °C or at least

80 °C, where high conversions can be achieved in a particularly short time.

The use according to the invention is also not restricted to polymerizations based on Michael additions, although in preferred embodiments at least two types of monomers that can be polymerized by Michael addition reactions are used in the photopolymerizable composition, which are even more preferably dolifiable by oxa-ene additions, oxa-yne additions or C-D addition reactions of C.M.-active compounds, in particular by oxa-ene additions. Particularly preferred examples of the monomers are combinations of (methacrylates or (methacrylamides) and alcohols, which are particularly suitable for generative manufacturing processes, preferably without SOLVENT MONOMIES.

each! in mass in the presence of the photobase generator.

In addition, the photopolymerizable compositions may further comprise at least one photosensitizer, preferably 9, 10-dibutoxyanthracene, and/or at least one racemic scavenger, preferably 2,86-ditert-butyl-p-crasol (butylhydrocyanoate, BHT), in order to increase the reaction rate and the conversion.

better and to increase the storage stability of the composition. In a second aspect, the present invention also provides a curing

a polyhetopolymerizable composition as described above

Photopolvener ready,

DS $ gl al X a} Y X 2

Re

Zn

C) where RT and RT are each independently selected from -M and -OCHs and where RI is selected from + and -CHa3 and X is either absent or selected from +O- and -S, wherein the salt is specifically selected from the group consisting of the following:

Sruppe selected is:

Tris(4-methoxyphenyDphosphantum-Z-(3-benzoylphenylproplonate (F}

Ed © A Ds

“5.

Dr |

AL

Tris(2,5-dimethoxyphenyohosphanium-2-(3-benzoyiohenylpropionet (3X 5 oO

ZA >

N H Ze Y

2

>

Di C ) oO zn

Tris(2,4,8-trimethoxyphenylenhasphonium-Z2-(3-benzoyiphenyoroplonaft (4x

| ß

Or U O0

7 Ze on 4

0 A © P rn

7743

and

Finally, the invention also relates to the use of one of these new triphenylphosphonium carboxylate salts as a phosphorus base generator in photopolymerizable

able compositions for the preparation of photopolymers, BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be explained below with reference to concrete examples

and the supporting drawings, which show the following:

Reaction 14 achieved reaction sales,

Fig. 2 is a photo-RDSC diagram of the photoohmic measurements performed in Example 15.

sation,

And Fig. 3A-0, Fig. 4A-8, Fig. BA-B and Fig. 6A-8 are photographs of the four In

Reispie! 21 three-dimensional bodies produced by hot lithography

Synthescabasniele — Seisniefe 1 to 6, Vergleichebelspiele 1 bis 8

To prepare the new phosphonium carboxylate salts, commercially available reagents were used, i.e. the respective triphenylphosphine (or in comparative example 2 BINAP, i.e. 2,2-bis(diphenylphosphino >17, 1'-5inaphihy) and the corresponding carboxylic acid (or in comparative example 3 triethylammonium tetraphenylborate), which were dried under high vacuum and used to form the salt without further purification. For comparative example 3, example 5 and example 6, the acid containing the respective ion (i.e. triethylammonium tetraphenylborate, 9-oxo-SAxanthene-Z-acetic acid or 9-oxo-SM-thioxanthene-2-acetic acid) was prepared according to the procedure described in Example 1.

placed, cleaned and dried,

The salt formation was carried out by introducing a solution or suspension of the acid in abs, THF, adding an equimolar amount of the acid (or for comparative example 2, half the molar amount of the bisphosphine BINAP), stirring for one hour, removing the solvent in a vacuum, washing the residue with a suitable solvent and drying the salt in a high vacuum. In the majority of the examples according to the invention, quantitative conversions {>90% ad. Th, "auant,"} were achieved. Characterization was carried out in each case by means of NMR spectroscopy.

scopy.

nohenyiphosphonium-2-(3-benzoyiohenyipropionate (VT}

OO A

(V4)

2-(3-Benzovighenyoropionic acid (1 eq., 2 mmol, 0.508 g) and trighenylphosphine (1 adz. 2 mmol, 0.525 ag) in abs, THF (6 ml) gave, after removal of the solvent, a sticky solid residue which was washed with petroleum ether and dried to give a white solid (yield: 0.8096 0, 87% AT

IH-NMR (600 MHz, CeDe) & 7.85 (t, 4M), 7.70 (de, ZH), 7.54 (dt, 1H), 7.47-7.33 (m, MH), 7.23 (dt, TH), 7.14-7.09 (m, 1H), 7.08-7.00 {m, 11H), 6.98 (5 TH}, 3.40 (m, IH ), 4.22 (d, 33H).

13C-NMR (151 Mbiiz, CeDe} 8: 195.31, 180.22, 140.21, 138.28, 137.73, 137.63, 133.91, 133.78, 121.96, 134.07 , 129.99, 129.42, 128.98, 128.54, 128.51, 128.48,

128.42. 128.08, 45.04, 17.74.

HPUNMR (243 MHZ, CeDe) 5: 5.41.

Tris(4-methoxyphenol)chosphine and 2-(3-benzoylphenol)propionic acid gave tris-

(4-methoxyphenyDohosphoniüm Ce jpropionate {FT}

AA Ss 2 UL / h

hey

ZZ OL

(1)

2-3-Benzoylphenoxyboroplanic acid (1 μg, 4.8 mmol, 0.458 g) and tri(4-methoxyphenyl)-2-oxosulfonic acid (1 eq, 1.8 mmol, 0.834 g) in abs. THF (7 ml) gave, after removal of the solvent, a white solid residue which was washed with THF and dried to give a white solid (yield: 1.092 g,

quant.}.

TEE NM (600 Miz, CeDe) &: 7.85 {s, TH), 7.70 (dd, 2M), 7.53 fat, 1HM), 7.41 (dg, SF), 723 (ct, 1 , 7.13-1.07 (m, TH), 7.05-7.00 {m, 4), 8.96 @ 1520, 6.7686.717 (m, 59), 3.38 fg, 1 }, 3.23 (sS, OM) 1.21 (0, SH)

O-NMR {151 MHz, CeDe) &: 194.42, 178.94, 150.48, 139.46, 137.39, 136.89, 4134.40, 134.26, 131.08, 130.21 , 129.11, 128.75, 128.58, 128.09, 127.55, 127.19,

113.43, 113.38, 53.49, 44.17, 16.95,

MPUNMR (243 MHz, CeDe) 5: - 10.32,

(2-meithoxyohenyiohosphonlum-2-{3-benzoylohenyDpropionate {2}:

(2)

2-{(3-Benzoviphenypropionic acid (1 aqu,, 4.8 mmol, 0.458 g} and tris(2-methoxyphenylphosphine (1 aqu,, 4.8 mmol, 0.634 g} in abs. THF (8 ml) gave, after removal of the solvent, a sticky solid residue which was washed with diethyl ether and dried to give a white solid (yield: 0.95009, 52% 1X

IH-NMR (600 MHz, CeDe) &: 7.85 (s, 14), 7.72-7.87 (m, 2H)}, 7.53 (dt, 24}, 7.23 (dt, 4H ), 7.12-7.07 (m, SH}, 7.08-7.00 (m, 2H}, 8.97 (1, IH), 6.78 (td, 3H), 6.51 ( m, 34), 2.39 (0, IM), 3.17 (8, OH), 4.21 (d, 83H).

BO-NMR (151 MHz, CeDs} &: 195.29, 179.91, 161.85, 161.73, 140.28, 138.26, 137.74, 134.05, 137.96, 131.08 , 125.95, 129.77, 128.96, 128.42, 128.08, 125.54,

125.43, 120.94, 110.06, 54.76, 45.03, 17.77.

SENMR (243 MMz, CeDe)} 6: 37.37,

On

Tris(2, 6-01 methoxyphenyl}phosphonium-Z2-(S-benzoylohenyöpropionate (3)

® i Se AS © N a.” Sf =

(3)

243-Benzylphenylpropionic acid (1 eq., 1.5 mmol, 0.381 g) and tris(2,6-dimethoxyphenylphosphine (1 eq., 1.5 mmol, 0.864 g) in abs, THF (7 ml) gave, after removal of the solvent, a white solid residue which was washed with THF and dried to give a white solid (yield: 1.045 g).

quani.}.

4NMR (800 Mbiz, OD) 8: 7.92 (d, 19), 7,747.70 {m, 2H), 7.55 (gt, 1H), 7.38 (dt, 7 7,457.10 tt, 83H) , 7.03 {m, SH), 7.10-7.02 a 8.31 (dd, EM), 3.58 (g, 19), 3.22 (8, 18F), 1.32 (d , 3H \

BONMR (151 MbMz, CeDe} 5: 195.44, 178.09, 162.73, 162.57, 141.32, 138.10, 137.84, 1341.89, 131.41, 120.98, 129.40 128.64, 128.50, 128.33, 128.03, 127.97, 1042.35, 55.42, 45.40, 15.25,

SIPNMR (243 MHz, CeDe} 8: 37.31,

“AD

DZ

Aris(2,4 S-trnmethoxyphenyDohosphonlum-2-{3-benzoyioghenyDoropionat {4} O sea

(4)

2-{3-Benzylphenyl nronic acid {1 aqu, 2.38 mmol, 0.6059) and tris(2,4,86-trimethoxoxyhenychosphine (1 agın, 2.38 mmol, 1.266 a} in abs, THF (9 ml) gave, after removal of the solvent, a beige, viscous solid residue, which was washed with ethyl acetate and dried to give a slightly beige solid (yield: 1.252 g, 67% of the weight).

H-NMR (800 MHz, CeDe) 5: 8.05 (4, 1H), 7.79-7.74 (m, 2H), 7.84 (dt, 15), 7.57 (gt, 4M) , 7.48-7.10 {m, 3H)}, 7.10:7.03 (m, 3H), 8.11 (d, SM), 3.88 (G, TH), 3.42 ( 8, OH}, 3.28 (s, 180), 1.48 (d, 3H).

BO-NMR (151 MiHz, CeDe) 5: 195.82, 177.51, 163.72, 163.67, 143.51, 138.07, 137.68, 132.09, 131.70, 130.07 , 129.71, 129.20, 128.10, 127.94, 071.45, 55.60,

55.48, 55.23, 54.82, 46.70, 19.12.

HPNME (243 MHZ, O6De) 5: 64.88.

A « =

2,2 -Bis(diophenylphosphonium)- 1, 1'-bingaphihyl and 2{3-R-benzoylpropionic acid gave 2,2 -8is(diphenylphosphonium)- 1, 1 -binaphihyl-DiIs[2-(3-benzoylpropionate)] (VZ)

(V2)

2-(3-Benzayipgheny)oropionic acid {2 eq., 1.5 mmol, 0.4068 g} and 2,2-bis(diphenylohosohino)- 1,T'-binaphihyl) (T eq., 0.8 mmol, 0.498 g} in abs. THF (S mil} gave, after removal of the solvent, a white solid residue which was washed with THF and dried to give a white solid (yield: 0.6909, 76% of T.}

H-NMR (400 Mbiz, CeDe) 5: 7.95 (t, 25), 7.89-7.70 (m, 7M), 7,707.43 (m, 119), 7.41-8.93 { m, 28H, 6.78 (m, 2M), 3.48 (g, 2M}, 1.31 (0, SM).

BONMR {1017 MHz, CaDse) & 1956.24, 180.07, 140.20, 138.20, 137.75, 134.56, 134.34, 133.08, 132.98, 132.88, 131, 92, 131.03, 129.94, 120.30, 128.96, 128.36,

128.06, 126.35, 125.72, 45.01, 17.18.

HEUANMR (182 MHZ, Cole) 8:15.04.

Uh

Trist2,4,S-trimethaxyphenyÖphosphin and triethylammoniumtetraphenylborate

ben Tns(2,4,6-trimethoxyphenyophosphonlunmletraphenyiborate {VS}

© Da

(V3)

Triethylammonium tetraphenylborate (1 eq., 1.0 mmol, 0.4219) prepared according to the literature (Faulkner et al, 4. Am, Chem, Soc. 137022), FZ24-7230 (2015) and tris{2,4,5-trimethoxyphenol (T eq., 1.0 mmol, 0.535 g)}) in abs. THF (7 ml) gave, after removal of the solvent, a white solid residue which was washed with hexane and dried to give a white solid.

(Yield: 045404, 54% dd. 1)

H-NMR (800 MHz, acetone-de} 8: 7.35 (m, SH), 6.94 (1 BM), 8.79 (tt, 44), 6.38 (d, EM), 3, 91 (s, OH}, 3.77 (sS, 184}.

BCO-NMR (1517 MHz, CeDe) 5: 205.32, 164.26, 136.16, 125.09, 121.36, 91.45, 91.40, 56.11, 55.40.

SIPNMR (243 MHz, acetone-de) 5: -52.03,

“AS

o SO

(V4)

Phenylolvoxalic acid (1 ÄAau,, 1.0 mmeoi, 0.1509} and tris(2,4,8-trimethoxyphenyl)-

ohosphine {1 ÄAdı., *L0 mmol, 0.533 9) in abs. THF (3 mi) gave after removal

of the solvent a beige, sticky residue which was identified with TME S $ S

washed and tracked, whereby a slightly beige, sticky solid

was obtained (yield: 0.8683 a, quani

H-NMR (400 MHz, Aceton-de) 5: 7.90-7.83 (m, ZH), 7.46-7.38 (m, 1M}), 7.32 (%, 25), 6 .15 (d, ZH), 3.74 (d, OH), 3.53 (sS, 18H).

BENMR (101 Mitz, Acelon-de}) &; 170.08, 163.19, 132.52, 120.39, 128.19, 91.35, 91.30, 55.79, 55.41, 55.08.

38

Tris(2,4,6-Yimethoxyphenol) and phihalmidoacetic acid gave tris(2,4,86-

trimethoxyphenyiohosphoniumoöhthalimidegacetate (V5):

'

Ö

{ } BD X Q x“ u ©

(V5)

N-phthaloyl (1 eq., 1.0 mmol, 0.205 g) and tris(2,4,8-thiethoxyphenyDphosphine (1 eq., 1.0 mmol, 0.5339) in abs. THF (3m) gave, after removal of the solvent, a beige solid residue, which was washed with THF and dried to give a slightly beige solid (yield:

{0.738 9, quani

1H-NMR (400 MiHz, acetone-de) 5: 7.89-7.81 (m, AH), 6.25-6.14 (m, SH), 4.34 (s, 2H), 3, 83 (s, OH), 3.59 (s, 18M).

BO-NMR (101 MHz, acetone-de} 5: 168.74, 167.56, 163.54, 183.47, 133.99, 122.83, 51.18, 91.16, 55.46, 54 .73, 40.96,

LET

{2,4 6-trimethoxyphermyphosphonlum-Z-(xanthone-Z-yibacetate (6)

* SS ES A | —_ > A m ‘ An ON A 0” OO

D

a

9 ö 9 Ö D Sy NN

he

(SS)

9-0xo-SH-xanthene-Z-acetic acid (1 aqu., 0.2 mmol, 51 mg) prepared according to the literature (Blake et al, Org Leif, 8(6), 1057-1060 (2006) with the exception that Kol Os was used instead of Cs2CCh) and tris(2,4,8-trimethoxypheny)phosphine (1 aqu., 0.2 mmol, 107 ma) in abs. THF (0.5 ml) gave, after removal of the solvent, a beige solid residue which was washed with THF and dried to give a slightly beige solid (yield: 158 mg,

quane

H-NMR (400 MHz, acetone-de} 5: 8.13 (dd, IM), 8.06 {d, TH), 7.77-.7.88 (m, 2H} 7.51.7.40 ( m, ZH}, 7.38-7.29 (m, 1H), 6.03 (s, SH), 3.66 (s, OH}, 3.61 (s, ZH), 3.39 (8 , 18H).

KO-NMR (107 MHz, Acelon-da} &: 171.64, 163.390, 136.66, 135.07, 126.60, 126.21, 124.05, 118.10, 117.98, 91.11 , 55.32, 54.59, 30.67.

=

“48.

Tris(2,4 S-Atrimethoxvphernyflohosphonium-Z-(hioxanthone-2-yDacetate (6X

Ooo

SEN

(8)

S-oxo-SM-ihloxanthene-Z-acetic acid (1 AÄau., 0.15 mmol, 41 mg) and tris(2,4,5-trimethoxyphenyDphosphine (1 AÄau., 0.415 mmol, 80 mg) in abs, THF (0.5 with) prepared according to the literature (Yılmaz et al, Macromeoi, Rapid Commun, 3/13), 1046-1051 (2016)) gave, after removal of the solvent, a light green solid residue, which was washed with THE and dried to give a pale green solid.

ten (yield: 121 mg, auant }

1H-NMR (400 MHz, acetone-de) 5: 8.42-8.29 (m, ZH), 7.83-7.54 (m, 49), 7.49-7.35 (m, { H), 5.97 (d, SH), 3.84 (s, 0.3H), 3.69 (s, 1.7H), 3.64 (s, OH), 3.37 (s, 18H ).

BCNMR (101 Miz, Aceton-de) 6: 163.25, 134.28, 132.58, 1729.95, 129.35, 126.43, 126.31, 126.19, 91.06, 55.22 , 54.48, 40.28.

Sections 7 to 12. Comparative Examples S to 10. — Photocatalysis "Oxa-Ene The new compounds according to the invention {1} to (8) prepared as described above and those of the comparative examples (V1} to (V5} were firstly

ohotoinitiated model reaction for their suitability as phosphobase general

“40.

Alkahof and its acrylate, specifically between Benzylalkohof as Michael

Danoar and kenzylacorylate as Michael accentor according to the following reaction:

The chemical shift of the two hydrogen atoms (highlighted in the scheme above) of the methylene group of the benzyl alcohol halide was used to determine the conversion. These each give a singlet in the THNMR spectrum, the peak of which for the benzyl alcohol contained as a solvent in the reaction mixture at 4.83 ppm, but after successful addition to the acylate double bond appears to be shifted downfield to 4.43 ppm (while that for the methylene group of the ester

bound benzyl alcohol at more than 5 ppm Rect)

The percentage turnover was therefore calculated according to the following formula

U (9%) = Ipfflp + Is} x 100 where Ip is the integral of the singlet peak in the product (i.e. at 4.43 o0m) and Ig is that of the peak in the reactant (Dei 4.53 ppm),

The reaction mixtures of the model reactions were (expressed as molar amounts) 1 eq. benzyl alcohol, 1 eq. benzyl acrylate, 2 mol% of the potential photobase generator, 0.02 mol% 9, 10-dibutoxyanthracene (BAnt) as photosensitizer and 2 mol% 2,6-ditert-butyl-D-cresof (butyloxytoluene, BHT) as radical scavenger. 10 to 15 mg of the formulations mixed at room temperature were filled into an aluminum DSC crucible and covered with a clear glass plate. The reaction mixtures were then heated to 80 °C and then irradiated at this temperature for 50 s with the medium pressure mercury lamp of the DSC device.

Light with a wavelength between 320 nm and 500 nm (with 133 miWWom®) bestrabhli,

TH

cooled and dissolved in ODOR, after which their TH-NMR spectra were recorded.

The sales calculated according to the above formula were as shown in the following

Table 1 shows

Table 4

Example Connection Sales (0) Comparison Example 6 (VD) Ö Example 7 (Ay 8

Example 8 Sn {2} 40

Example 9 {3} 58

Example 10 {4} 65

Example 11 {8 8

Example 12 {5} S4

Comparison example 7 (VZ) Q Comparison example 8 BY 9 Comparison example 9 (V4) 8 Comparison example 10 (V5)} GT

From this it is clear that none of the comparison substances was able to generate conversions, i.e. to be split upon irradiation and to trigger the Michel addition reaction. This means that neither the unsubstituted triphenylphosphonium nor the BINAP cation in combination with inventive ions nor the tris(2,4 S-irimethoxyphenylphosphonium cations) in combination with nuclear anions are suitable as photobase generators.

suitable

You

re-derivatives, it was shown that the number of substituents as well as their position significantly influence the reactivity: The ortho position of the methyloxy group on the phenyl residues of compound (2), i.e., as substituent R}, is to be preferred over the para position of compound (1) as substituent RZ. However, the conversions of 10% and only 6% achieved with this can be reduced by &

Increasing the number of substituents to two or three even multiplied the conversion: 58 % of conversion was achieved with the dimethoxy- and 69 % with the trimethyloxy-substituted compound.

dung {3} or {4},

On the other hand, it can also be seen that a cation between the two benzyl rings in the aromatic anion improves the ability of the salt to act as a photobase generator even further: In combination with the tris(2,4,6-trimethylethoxyphenylphosphonium cation, 81% conversion was achieved with the 2-(xanthone-2-methylacetate anion and 834% conversion with the 2-(thioxanthone-2-methylacetate anion for the compounds (5) and (6), respectively. The inventors therefore assume that similar results can also be achieved with a chemical bond, -OMHa-, OOo +CHa2-CL or -C(=O). as substituent X in formula {1} - as well as with a longer alkyl radical as a substituent.

tuent RO (such as ethyl or praopyl). However, an increase in the molecular weight of the photobase generator is of course not preferable as long as it

no significantly better results can be achieved,

Figure 13, Comparative Example 11 — Photocatalysis TC. 0" The exact compound (4) and a known catalyst of the O-C-

Michela delition, namely CGT 1183 (from BASF) of the following formula: OD Sy | > ö “DD

In photo-OSC experiments analogous to those above, the achievable conversions were investigated in a model reaction with diethylimalonate as Michael donor and again benzyl lacıylate as Michael acceptor according to the following reaction:

A

H za hut Ha rn a A . N MW Uh " AD

°

N

o © OÖ 9 | SUN HH $ { ©

En |

0” 80

De

To determine the conversion, the chemical shift of the two hydrogen atoms (highlighted in the above scheme) of the benzylmethylene group of renyl acrylate in the product and in the product was used.

The reaction mixtures in this case were 1 eq. diethylmalonal, 2 eq. benzyl acrylate, 2 mol-% of compound {4} or CO 1193, 0.02 mol-% BAnt as chotosensiizer and 2 mol-% BHT as radical scavenger. The reaction conditions for example 13 were the same as before (80 °C, 2 x 50 s exposure, each followed by 850 s heating). The conversions calculated from the !H-NMR spectra are given in Table 2 below.

to

Table 2

Example ' Connection Sales (%) — Comparison Example 11 OGE1103 35 Example 13 {4} — ze DB

24 / 43

The suitability of the compound as a catalyst for C-C Michael addition ions is also demonstrated.

Example 14 — Reaction temperature

Since it was assumed that the conversions could be further increased by increasing the concentration of the photobase generator, the sensitizer or the reaction temperature, the inventors carried out further photo-DSC experiments with compound (4), with which a conversion of 60% had previously been achieved in the Qxa-En experiments.

carried out,

The concentration of the photobase generator was increased from 2 to 5 mol% and that of the sensitizer from 0.02 to 1 mol%. The temperature was increased in each batch from room temperature (258 °C) in steps of 25 °C to 150 °C. The conversions calculated again from the respective FHL-NMR spectra as described above are given in Table 3 below and in

Fig. 1 graphically shown.

Table 3

Temperature (°C) Conversion /%) 25 to 20 Ma 50 | 55 75 BE 100 8 to 125 74 150 48

From these results it can be concluded that the optimum reaction temperature for this reaction mixture is likely to be in a range between 80 °C and 90 °C. On the other hand, it can be seen that the reaction conversion is mainly determined by the

Increased photobase generatrix concentration compared to those with compound

THERE

be increased konnie

From this it can be further deduced that the only mono-methyl-substituted compounds (1) and {Z), which had given comparatively poor results under the above reaction conditions of Examples 7 and 8, can also be used industrially as pholobase generators after optimization of the parameters.

This also applies to ortho/para-disubstituted varlarıtes, which have not yet been tested — especially in combination with a

enclosed anion of the formula {P}.

Ralsojal 35 Photenolvmerization

To confirm the suitability of the photobase generators according to the invention for the production of photopolymers, another photo-DSC experiment was first carried out using multifunctional monomers. Specifically, a reaction mixture of 1 eq. trimethylolpropane (TMP), 1 eq. trimethylolpropane lat {TMPTA)N 5 mol-36 of the compound (4), 2 mol-% BHT as a radical scavenger and BAnt as a photosensitizer was prepared, the amount of which was now reduced to 0.02 mol-%. The reaction temperature, however, was increased to 100 °C.

DR ; 3 b x e=s Lo sa > Wed — A TME TAADTA

As can be seen in Fig. 2, a strong exotherm was observed just a few seconds after the start of the exposure, which again subsided after just over a minute.

which had completely subsided, indicating complete conversion of the reactants.

“D8

appropriate photopolymers can be produced in a very short time,

Example 16 Phototransformation for the preparation of a sizing agent A reaction mixture of 1 eq TMP, 1 eq TMPTA, 2 mol% of the compound (4), 2 mol% BMT as radical scavenger and 0.02 mol% BArnt as photosensitizer was treated with

a doctor blade in a layer thickness of 100 µm on a glass plate,

This was heated to 80 °C in a UVM-Cfen INTELLERAY 600 from Uvitron International and irradiated with the mercury broadband (M lamp of the oven with LALLI light at 320500 am. After an exposure time of only 1 min, a harı

te transparent coating on the glass plate,

Examples 17 to 70, comparative examples 12 and 13

To determine the reaction parameters of the above photopolymerization reaction in more detail, further photo-DSC experiments were carried out with reaction mixtures analogous to Example 16, consisting of 1 mol% TMP, 1 mol% TMPTA, 2 mol% of the respective photobase generalor, 2 mol% MT as radical scavenger and 0.02 mol% BAnt as photopolymerization reaction.

sensiizer undertaken.

The performance of the compounds according to the invention was investigated {1}

is (4), i.e. the tris({methaxyphenybohosphonium-2-(3-benzoyl)propionates substituted at different positions or with a small number of methoxy groups, as well as those from comparative examples 3 and 4 with different anions, i.e. tris(2,4,6-imethoxyphenolhosphoniumtetrahydroborate {(V3} and tris(2,4,6-timethoxyphenolhosphoniumphenyloxylate (V4},

From the corresponding photo-DSC diagrams, the peak area (J/q) as a measure of the conversion achieved, the peak height ({mW/ma)} as a measure of the polymerization rate and the time to reach 95% of the conversion, tos {6}, as a measure of the speed at which the overall reaction takes place, were determined. The results

are given in Table 4 below,

“26.

| Example connection | Area (Ja: | HShe (mWima) ton {8} Comparison example 12 O3 233 10,3 48.2 Comparison example 13 (Va) 155 5.3 52,5 Example 17 398 Ca 26 Example 18 (2) 288" 18,3 38,6 Example 19T (3) 314 18,7 39,0 Example 20 (4) 336 EG 887

At first glance, it can be seen that the two comparison substances, which in the above comparison examples 8 and 9 were unable to generate any salt as catalysts for the oxa-acetyl adaptation between benzyl alcohol and benzyl acrylate, also showed activity as photobase generators. However, they were clearly outperformed by the four compounds according to the invention in all respects. The latter gave peak areas that were around 1.5 or 2 times larger, a peak height that was around 2 or 4 times larger, and lines for iss that were around 20% shorter, which shows that

they were able to generate significantly higher sales in a shorter period of time.

In comparison to the above results of the photo-DSC experiments for the reaction between benzyl alcohol and styryl acrylate, it was not only surprising that (V3) and (V4) now also acted as photobase generators, but also that all four compounds according to the invention gave comparable results in the present examples 17 to 20: they did not differ by more than 10% in any of the three parameters, although the conversions achieved in the earlier examples 7 to 10 had been lower (5%, 10%, 58% and 60% conversion, respectively).

Without wishing to commit to a theory, the inventors assume that both are due to the Trommsdorf effect or GerEHect, through which the reaction rate increases in the course of polymerizations with increasing conversion, since the reaction

reaction mixture, the reaction heat can be dissipated more and more poorly, WO-

B.F.

Diluting effect of a solvent can be observed.

In any case, these results also demonstrate the superiority of the combinations according to the invention of formula (PD) of methoxy-substituted trifluorophosphonium cations and the anions of defined phenylacetic acid or phenylpropionic acid derivatives over similar other salts whose cation and/or anion does not correspond to the

Definition according to the present invention,

Haisniel 21 — Hot Lähoarachle

Due to the fact that the reaction mixtures tested required or were preferable to high reaction temperatures, they are extremely well suited for 30-printing by means of lithography, &‚A5. layer-by-layer exposure of the liquid mixtures with a laser while heating to elevated temperatures to produce three-dimensional photopolymers with predefined formats.

and structure,

For this purpose, four experiments were carried out, each with the same reaction mixture as in example 18, i.e. 1 eq. TMP, 1 eq. TMPTA, 2 mol% of the compound (4), 2 mol% BET and 0.02 mol% BAnt. The first three were heated to 80 °C in a Cubiecure Callgma 2009 Hot Lithography System and hardened layer by layer with a layer thickness of 50 μm to form three-dimensional bodies using a 375 nm laser (60 HA) with a scan rate of 200 mm/s. Photos of the molded bodies thus obtained are shown in the

Pie, 3 and 4 shown,

First, a full square pyramid (Fig. 3A) and then a hollow cube (Fig. 3B) were produced. After that, a hollow pyramid was produced, which can be seen in Fig. 3C and Fig. 4, where in Fig. 4A the area of the four struts is marked, of which Fig. 4B shows an enlarged view, from which it can be seen that the layers hardened one after the other in the 3D printing even with

visible to the naked eye,

“OB

The printing was again carried out at 80 °C with an exposure time of 18 s and an intensity of 75 mW/cm®. In this case, however, Digital Light Processing, or DLP for short, was used, in which the light is projected onto the reaction mixture to be hardened using a projector or beamer instead of a laser using reflective micromirrors.

is directed,

In Figs. SA and SB light microscopic images of this complex Mohl cube are shown at different magnifications, from which the high resolution

solutions of this SD printing process,

All four experiments, as well as the other examples, clearly demonstrate the usability of the triphenylphosphonium sarboxylate salts according to

Formula {N as photobase generafogren,

“THE

Claims (1)

4 Use of a tripheryiohosphonium carboxylate salt of the following formula (1) as a photobase generator in a photopolymerizable composition comprising at least one type of monomer for the preparation of photo- polymers by curing the composition by irradiation with light of a suitable wave length: 2 > 9 R) 7 | Lo De GO () wherein RT and R?* are each independently selected from -H and -OCHz, wherein on each of the three phenyl residues at least one of R' and R® is -QOMs, and wherein RS is selected from -H and OH and X is either absent or consists of a chemical bond, -Chio-, «CO CHe-CH2-O-, C(=C, -Q- and -S-, 2, Use according to claim 1, characterized in that at each of the three phenyl radicals at least one R7 stands for -OCHs, 3 Use according to claim 2, characterized in that the phosphonium cation of the salt is the cation of one of the following triphenylphosphines: tris(2-methaxyphenylphosphine, tris(2,6-dimethoxyphenylphosphine or tris(2,4,6-trimeihoxyphenylphosphine,. 4. Use according to one of claims 1 to 3, characterized in that X is missing or consists of a chemical bond, Pa 31 u 31 o 6. Use according to claim 5, characterized in that the photobase generator is selected from the following triphenviphosphonium carboxylate salts: tris(2,6-dimethylphenylphosphonium-2-{3-benzoyiphenylphosphonate, tris«(2,4,6-trimethoxyphenylphosphonium-2-(3-benzoyiphenylphosphonate, tris(2 S-dimethOxypheny)phosphonium-2-(xanthone-2-yl)acetate, tris(2,4,8-irimethoxyphenolphenyl)phosphonium-Z-(xanthone-2-yl)acetate, tris(2,6-dimethoxyphenylphosphonium-Z-(ihloxareihon-2-yl)acetate and tris(2,4,8-trimethoxyphenylphosphonium-2-(thloxanthon-2-yl)acetal, 7. Use according to one of claims 1 to 6, characterized in that the photopolymerizable composition is applied to a substrate and cured by irradiation to form a coating or is cured in a general manufacturing process by means of layer-by-layer irradiation to form a three-dimensional object, wherein the curing is optionally carried out with heating and wherein the photopolymer obtained is optionally subjected to a thermal mixed post-treatment, B, Use according to claim 7, characterized in that lithography is carried out as a generative manufacturing process with heating to a temperature of at least 50 °C or at least 70 °C or at least 50 °C, 8, Use according to one of claims 1 to 8, characterized in that at least two types of monomers polymerizable by Michael addition reactions are used in the photopolymerizable composition. Ur active compounds, preferably by oxa-ene additions, are polymerizable, 11. Use according to claim 10, characterized in that a combination of (meilacrylates or (meilacrylamides) and alcohols as monomers, before ZugswWeise solvent is used in mass, 12. Use according to one of claims 1 to 11, characterized in that the photopolymeric composition further comprises at least one photoSensitizer, preferably 9, 10-dibuloxvarthracene, and/or at least one radical Approx scavenger, preferably 2,5-di-tert-butyvi-po-cresol (bubyihydroxytoluene, BET). 12 Photopolymer, which is obtained by curing a phofopolymerizable compound composition as described in any one of claims 1 to 12, 14. Trighenylnhaosphonlumocarboxylate salt of the following formula (PD 5 x X 8 oO 6 Ur ; A De a2 e © wherein R' and RR? are each independently selected from -H and -OCHs and wherein R* is selected from -H and -CHa3 and X is either absent or selected from OD and -SAUS, wherein the salt is selected from the group consisting of the following: "338 wherein the salt is selected from the group consisting of the following "338 DD © nn Pan Tris(@-methoxyohenyDphosphanium-2-(3-benzoyiphenyÜprogionate (2}: | DA A & KL LOL N Si u_- N ; > UV I er CO Po ES u u) Tris(2, Sy eleehonum dd ben phem pr epEne SE | A CO ® | PS N A 2 | L y / Da Y ix DA De Ss © = BA U ANA Ss YO "u Ä SA A J Upper Austria DD Trns(2,4 S-trimethoxyphenyDphosphorium-2-(xanthone-zyfacetate (5): OO AA En © A VL LT | Oi and Üris(2,4,E-tr (methoxypheny! phosphoni un-Z-(thloxanthone-2-yacelate (8X) m ; Q © On Su A DS “35. Creation of photopolymers, Vienna on O7, August, 2023 TE AS ts E SD Or. N N Susss Ss Ns 385 - 36 =