Composition for producing a polymer, use of the composition for producing a polymer, and polymer

Abstract

The invention relates to a composition for producing a polymer and to a polymer. The invention also relates to uses of the composition. The composition is characterized in that the composition comprises a photoinitiator, an isocyanate group-free reactive diluent based on (meth)acrylic acid, and oligomers, wherein each of the oligomers contains or consists of a condensation product of itaconic acid and at least one dialcohol and does not have a respective acrylic acid group or a methacrylic acid group at the end groups thereof. By virtue of the aforementioned composition, it is possible to produce polymers with a significantly reduced propensity for UV-induced darkening, i.e., polymers with which rarely any UV-induced discoloration (e.g., yellowing or browning) occurs.

Description

[0001] Composition for producing a polymer, use of the composition for producing a polymer, and polymer

[0002] A composition for producing a polymer and a polymer are provided. Uses of the composition are also proposed. The composition is characterized in that it contains a photoinitiator, an isocyanate-free reactive diluent based on (meth)acrylic acid, and oligomers, wherein the oligomers each contain or consist of a condensation product of itaconic acid and at least one dialcohol and each have no acrylic acid residue and no methacrylic acid residue at their end groups. The composition makes it possible to produce polymers whose susceptibility to UV-induced darkening is greatly reduced, i.e., in which hardly any or no UV-induced discoloration (e.g., yellowing or browning) occurs.Formulations of radically curing materials are known in the prior art, which contain polyester-based or polyurethane acrylate-based oligomers and acrylic acid-, methacrylic acid- or acrylamide-based reactive diluents, wherein the oligomers may contain itaconic acid residues (see, for example, WO 2010 / 099009 A1 and DE 10 2015 105 993 A1).

[0003] The formulations known in the prior art either result in (slightly) yellow-colored polymers (resins) after curing, or in polymers that are colorless immediately after curing, but which darken within days to weeks under the influence of UV radiation (e.g., during post-curing in a UV post-curing oven or even in indoor light), i.e., turn yellow or even brown. This discoloration of the produced polymers can be undesirable for many applications.

[0004] Based on this, the object of the present invention was to provide a composition for producing a polymer and a polymer which does not cause the disadvantages known in the prior art. In particular, the composition should make it possible to produce a polymer that does not exhibit any darkening (i.e., no brown discoloration) even within days to weeks after its production. Furthermore, a use of the composition should be proposed and a corresponding polymer should be provided.

[0005] The object is achieved by the composition having the features of claim 1, the polymer having the features of claim 10 and the use having the features of claim 12. The dependent claims show advantageous developments.

[0006] According to the invention, a composition for producing a polymer is provided, containing or consisting of: a) oligomers each containing or consisting of a condensation product of itaconic acid and at least one polyalcohol, wherein the at least one polyalcohol is a dialcohol; b) a reactive diluent selected from the group consisting of acrylic acid ester, methacrylic acid ester, acrylamide, methacrylamide and combinations thereof; and c) a photoinitiator; characterized in that the oligomers each have no acrylic acid residue and no methacrylic acid residue at their end groups and the reactive diluent has no isocyanate group.

[0007] The composition according to the invention can be used to produce a polymer whose susceptibility to UV-induced darkening is greatly reduced, ie, the polymer according to the invention exhibits little to no UV-induced discoloration (e.g., yellowing or browning). Even if the polymers exhibit a slight yellowing due to a pre-existing slight yellowing of the oligomers in the formulation, this yellowing disappears in the cured formulation (i.e., in the polymers) after exposure to UV light.

[0008] The reason for this property of the polymers is that the oligomers present in the composition do not have any acrylic acid residues or methacrylic acid residues at their end groups, and the reactive diluent does not contain any isocyanate groups. Due to the absence of a (meth)acrylic acid residue at the end groups of the oligomers, these cannot react with the photoinitiator after curing to form discolored products. The absence of an isocyanate group in the reactive diluent also rules out the reactive diluent binding to the end groups of the oligomers via its isocyanate group in order to modify them with a (meth)acrylic acid residue before or after radical curing. This ensures that the oligomers do not have any acrylic acid residues or methacrylic acid residues at their end groups during radical polymerization and also thereafter. Consequently, darkening of the polymers due to UV light is prevented or even eliminated.allows slight gel discoloration resulting from the oligomers in the formulation to disappear after UV light exposure.

[0009] The condensation product of the oligomers can be produced at a temperature of not more than 175 °C, preferably not more than 150 °C, particularly preferably not more than 130 °C. The lower the production temperature, the lower the susceptibility of the polymer produced from the oligomers to darkening.

[0010] The condensation product of the oligomers can be prepared in a nitrogen atmosphere. The nitrogen atmosphere during the preparation of the oligomers can further reduce the susceptibility to UV-induced darkening of the polymers produced from the oligomers.

[0011] The oligomers may be present in the composition in a concentration of 20 to 80 wt.%, preferably 30 to 70 wt.%, particularly preferably 40 to 60 wt.%, very particularly preferably 45 to 55 wt.%, in particular 48 to 50.9 wt.%, based on the total weight of the composition.

[0012] Furthermore, the oligomers can each have a molar mass in the range of 250 to 10000 g / mol, optionally in the range of 1500 to 9500 g / mol, wherein the molar mass refers to a molar mass determinable by size exclusion chromatography.

[0013] Apart from that, the oligomers can have an acid number in the range of <20 mg KOH / g oligomers, preferably in the range of <15 mg KOH / g oligomers, particularly preferably in the range of <10 mg KOH / g oligomers, and most preferably in the range of <5 mg KOH / g oligomers. The acid number of the oligomers refers in particular to an acid number determined titrimetrically according to ISO 2114-2000. The lower the acid number, the lower the susceptibility of the oligomers to reacting with the photoinitiator of the composition according to the invention to form a polymer that exhibits UV-induced darkening. Lower acid numbers thus result in a lower susceptibility of the polymer to UV-induced discoloration.

[0014] Furthermore, the oligomers can have a molar ratio of hydroxyl end groups to carboxyl end groups in the range of >4, preferably in the range of >6, particularly preferably in the range of >12, in particular in the range of >25. The molar ratio of hydroxyl end groups to carboxyl end groups in the oligomers relates in particular to a quotient of the hydroxyl number of the oligomers as the numerator and the acid number of the oligomers as the denominator (i.e. molar ratio = hydroxyl number : acid number). The higher this molar ratio, the lower the molar proportion of acid end groups in the oligomers and the lower the susceptibility of the oligomers to reacting with the photoinitiator of the composition according to the invention to form a polymer that exhibits UV-induced darkening. Higher molar ratios therefore result in a lower susceptibility of the polymer to UV-induced discoloration.

[0015] Furthermore, the oligomers can have a hydroxyl number in the range of > 80 mg KOH / g oligomers, preferably > 100 mg KOH / g oligomers, particularly preferably > 120 mg KOH / g oligomers, especially > 140 mg KOH / g oligomers. The hydroxyl number of the oligomers refers in particular to a hydroxyl number determined according to ISO 4629-1996. The higher the hydroxyl number, the lower the acid number of the oligomers can be, which reduces the susceptibility of the oligomers to reacting with the photoinitiator of the composition according to the invention to form a polymer that exhibits UV-induced darkening. Higher hydroxyl numbers therefore result in a lower susceptibility of the polymer to UV-induced discoloration.

[0016] In a preferred embodiment, the oligomers are linear polyesters (i.e., non-branched polyesters).

[0017] According to the invention, the polyalcohol is a dialcohol, wherein the dialcohol is preferably selected from the group consisting of saturated aliphatic dialcohols. The saturated aliphatic dialcohol is preferably selected from the group consisting of 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, isosorbide, cyclohexanedimethanol, polyether polyols based on ethylene glycol, 1,3-propanediol, and 1,4-butanediol, and combinations thereof. The saturated aliphatic dialcohol is in particular selected from the group consisting of neopentyl glycol, 1,6-hexanediol, and combinations thereof.

[0018] The oligomers can each contain or consist of a condensation product of itaconic acid, at least one polyalcohol, and at least one polyacid other than itaconic acid. The at least one polyacid other than itaconic acid can be a diacid, wherein the diacid is preferably selected from the group consisting of aromatic or saturated aliphatic diacids.

[0019] The diacid is particularly preferably an aromatic diacid selected from the group consisting of phthalic acid, dihydrophthalic acid, tetrahydroxyphthalic acid, hexahydroxyphthalic acid, isophthalic acid, dihydroisophthalic acid, hexahydroisophthalic acid, terephthalic acid, dihydroterephthalic acid, tetrahydroterephthalic acid, hexahydroterephthalic acid, furandicarboxylic acid, dihydrofurandicarboxylic acid, tetrahydrofurandicarboxylic acid, and combinations thereof, wherein the aromatic diacid is in particular phthalic acid.

[0020] The diacid may alternatively be a saturated aliphatic diacid selected from the group consisting of oxalic acid, malonic acid, succinic acid, malic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and combinations thereof, wherein the saturated aliphatic diacid is preferably selected from the group consisting of sebacic acid, adipic acid, and combinations thereof.

[0021] The reactive diluent may be present in the composition in a concentration of 20 to 80 wt.%, preferably 30 to 70 wt.%, particularly preferably 40 to 60 wt.%, very particularly preferably 45 to 50 wt.%, in particular 46 to 48 wt.%, based on the total weight of the composition.

[0022] Furthermore, the reactive diluent can be selected from the group consisting of hexanediol diacrylate, trimethylolpropane triacrylate, neopentyl glycol diacrylate, acryloylmorpholine, isobornyl acrylate, pentaerythritol triacrylate, hydroxyethyl methacrylate, tricyclodecanediethanol diacrylate, and combinations thereof. These reactive diluents have the advantage that they are colorless and can polymerize via radical polymerization with the oligomers in the formulation according to the invention to form uncolored polymers. The reactive diluent particularly preferably contains or consists of acryloylmorpholine and / or isobornyl acrylate.In a preferred embodiment, the reactive diluent does not have a group that is suitable for forming a covalent bond with a carboxyl group during radical polymerization of the composition and does not have a group that is suitable for forming a covalent bond with a hydroxy group during radical polymerization of the composition. This makes it possible to reliably prevent the reactive diluent in the composition (e.g. before or during radical polymerization of the composition) from binding to the end groups of the oligomers by forming a covalent bond and modifying these with a (meth)acrylic acid residue. Consequently, it can be better ensured that after radical polymerization the end groups of the oligomers are still free of an acrylic acid residue and a methacrylic acid residue and thus do not react with the photoinitiator to form discoloring orcan react with darkening substances.

[0023] The photoinitiator may be present in the composition in a concentration of 0.1 to 6 wt.%, preferably 0.5 to 5 wt.%, further preferably 1.0 to 4.5 wt.%, particularly preferably 2.0 to 4.0 wt.%, most preferably 2.5 to 3.5 wt.%, based on the total weight of the composition.

[0024] Furthermore, the photoinitiator can be selected from the group consisting of α-hydroxyketone, α-alkoxyketone, α-aminoketone, acylphosphine oxide, azo compound, and combinations thereof. The photoinitiator is preferably selected from the group consisting of 2-hydroxy-2-methyl-l-phenylpropan-l-one, 1-hydroxycyclohexylphenyl ketone, α,α-dimethoxy-α-phenylacetophenone, 2-benzyl-2-(dimethylamino)-l-[4-(4-morpholinyl)phenyl]-l-butanone), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, azobis(isobutyronitrile), and combinations thereof. In particular, the photoinitiator is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO). TPO has the advantage of being colorless and thus does not contribute to yellowing of the polymer produced with this photoinitiator. Furthermore, TPO can react with long-wave UV light (e.g.,UV light with a wavelength of > 380 nm), which allows for lower exposure to harsh UV radiation during curing of the composition. Other photoinitiators require a wavelength of < 380 nm for the reaction and / or exhibit a strong yellow color, which can contribute to yellowing of the polymer produced with these photoinitiators.

[0025] The composition may further contain a polymerization inhibitor.

[0026] The polymerization inhibitor is preferably present in the composition in a concentration of >0 to 0.4 wt.%, preferably 0.01 to 0.2 wt.%, particularly preferably 0.02 to 0.1 wt.%, very particularly preferably 0.03 to 0.07 wt.%, in particular 0.05 wt.%, based on the total weight of the composition.

[0027] Furthermore, the polymerization inhibitor may contain or consist of methoxyphenol and / or 3,5-bis(l,l-dimethylethyl)-4-hydroxytoluene.

[0028] The composition may further contain at least one additive or no additive selected from the group consisting of pigment, effect pigment, dye, stabilizer, UV absorber, antioxidant, biocide, flow control agent, rheology modifier, defoamer, antistatic agent and combinations thereof.

[0029] According to the invention, a polymer is also provided, containing or consisting of a) covalently bonded via a carbon-carbon bond

[0030] Residues of oligomers each containing or consisting of a condensation product of itaconic acid and at least one polyalcohol, wherein the at least one polyalcohol is a dialcohol, and

[0031] Residues of a reactive diluent selected from the group consisting of acrylic acid ester, methacrylic acid ester, acrylamide, methacrylamide, and combinations thereof, wherein the reactive diluent does not have an isocyanate group; b) a photoinitiator embedded in the polymer; characterized in that the residues of the oligomers each have no acrylic acid residue and no methacrylic acid residue at their end groups, and the residues of the reactive diluent each have no isocyanate group. The polymer according to the invention has a low susceptibility to darkening, i.e., hardly any or no UV-induced discoloration (e.g., yellowing or browning) occurs in the polymer according to the invention. Even if the polymers exhibit a slight yellowing, this yellowing disappears after weathering with UV light.

[0032] In a preferred embodiment, the polymer according to the invention was produced using a composition according to the invention. Consequently, the polymer according to the invention can have at least one feature that necessarily results from the use of the composition according to the invention in the production of the polymer according to the invention.

[0033] The use of the composition according to the invention for producing a polymer by radical polymerization is proposed. The polymer according to the invention is preferably produced using a UV-curing 3D printing process or such a process is used for its production.

[0034] The radical polymerization can be induced by irradiating the composition with UV light, preferably with UV light of a wavelength of > 380 nm (part of the near-UV range).

[0035] Furthermore, the radical polymerization can be carried out at a temperature of < 40 °C, preferably < 35 °C, particularly preferably < 30 °C, in particular < 25 °C.

[0036] The subject matter of the invention will be explained in more detail with reference to the following figure and the following examples, without wishing to restrict it to the specific embodiments shown here.

[0037] The figure shows photographs of test strips (i.e. cured polymers) prepared from six different formulations, the composition of which is given in Example 3. The figure shows the test strips immediately after curing of the formulations (see upper photo in the rows of the figure) and after post-curing in a UV post-curing oven for 2 x 15 minutes (see lower photo in the rows of the figure), on the one hand without artificial weathering with UV light from a xenon lamp in an artificial weathering device for 72 h (ATLAS Suntest) (see middle column in the figure) and on the other hand after such artificial weathering (see right column in the figure).

[0038] Example 1 - Synthesis of the first itaconic acid-based oligomers, each of which has no acrylic acid residue and no methacrylic acid residue at their end groups ("Oligomers 1")

[0039] In a 1L 3-neck flask equipped with a water separator, reflux condenser, and precision glass stirrer, 284.16 g of 1,6-hexanediol, 131.97 g of phthalic anhydride, and 115.53 g of itaconic acid are placed. In addition, 0.15 g of 4-methoxyphenol and 0.2 g of 3,5-bis(l,l-dimethylethyl)-4-hydroxytoluene are added as inhibitors. 15 g (0.15 mol) of heptane are then added. The reaction mixture is then evacuated three times and flushed with nitrogen. It is then slowly heated to 130 °C under a nitrogen atmosphere while stirring (100-250 rpm) until a homogeneous melt is formed. Next, 1.95 g of methanesulfonic acid is added as a catalyst, and the temperature is adjusted to 130 °C under continuous reflux. The resulting water collects in the water separator. The reaction progress is monitored by titrating the acid number. This type of reaction monitoring is common in this field and is well known to those trained in this type of synthetic chemistry.Once the acid number has reached a value lower than 5 mg KOH / g, the heptane is removed under reduced pressure and the resulting colorless, transparent resin (designation: "Oligomers 1") is bottled and characterized.

[0040] Acid number: <5 mg KOH / g

[0041] Hydroxyl number: 142 mg KOH / g

[0042] Double bond content: 1.8 mmol / g

[0043] Example 2 - Synthesis of second itaconic acid-based oligomers which do not have an acrylic acid residue or a methacrylic acid residue at their end groups ("Oligomers 2")

[0044] In a 1L 3-neck flask equipped with a water separator, reflux condenser, and precision glass stirrer, 246.77 g of 1,6-hexanediol, 54.37 g of neopentyl glycol, 70.03 g of malic acid, and 203.90 g of itaconic acid are placed. 0.15 g of 4-methoxyphenol and 0.2 g of 3,5-bis(l,l-dimethylethyl)-4-hydroxytoluene are added as inhibitors. 15 g (0.15 mol) of heptane are then added. The reaction mixture is then evacuated three times and purged with nitrogen. It is then slowly heated to 130 °C under a nitrogen atmosphere while stirring (100-250 rpm) until a homogeneous melt is formed. Next, 1.95 g of methanesulfonic acid is added as a catalyst, and the temperature is adjusted to 130 °C under continuous reflux. The resulting water collects in the water separator. The reaction progress is monitored by titrating the acid number. This type of reaction monitoring is common in this field and well known to those trained in this type of synthetic chemistry.Once the acid number has reached a value lower than 5 mg KOH / g, the heptane is removed under reduced pressure and the resulting slightly yellowish, transparent resin (designation: "Oligomers 2") is bottled and characterized.

[0045] Acid number: <5 mg KOH / g

[0046] Hydroxyl number: 150 mg KOH / g

[0047] Double bond content: 3.1 mmol / g

[0048] Example 3 - Preparation of compositions according to the invention and reference compositions

[0049] The components of the formulations used to produce a polymer and the proportion of each component (relative to the total weight of the respective formulation) are shown in Table 1 below.

[0050] Table 1

[0051] Oligomers 1: aliphatic oligomers, each a condensation product of 1,6-hexanediol, phthalic acid (more precisely: phthalic anhydride), and itaconic acid, and each having no (meth)acrylic acid residue at the end groups (for preparation see Example 1); Oligomers 2: aliphatic oligomers, each a condensation product of 1,6-hexanediol, neopentyl glycol, malic acid, and itaconic acid, and each having no (meth)acrylic acid residue at the end groups (for preparation see Example 2);

[0052] Oligomers 3 (reference): Commercially available 2-functional, aliphatic urethane methacrylate oligomers that do not contain itaconic acid and have methacrylic acid (or a methacrylate residue bound to the oligomers) at the end groups;

[0053] Reactive thinner “ACMO”: Acryloylmorpholine (does not contain an isocyanate group);

[0054] Reactive thinner “IBOA”: Isobornyl acrylate (does not contain an isocyanate group);

[0055] Photoinitiator "TPO": diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide;

[0056] Dye: "Blue 30C591" (The Shepard Color Company, CAS

[0057] # 1345-16-0). Formulation No. 3 was added with this dye to compensate for a very slight yellowing of oligomer 2

[0058] Example 4 - Curing of the compositions according to the invention and reference compositions and analysis for discoloration

[0059] Formulations 1 to 6 from Example 3 were processed into test bars in a DLP 3D printer under identical conditions, using layer thicknesses of 10 μm and exposure times of 3 seconds. The test bars were then washed with isopropanol. To investigate color stability, the test bars, which were either not subjected to post-curing or were subjected to post-curing, were subsequently irradiated for 72 hours with UV light from a xenon lamp in an artificial weathering device (ATLAS Suntest).

[0060] The results are shown in Figure 1 and the following Table 2 and are described in more detail after Table 2.

[0061] Table 2

[0062] Formulation No. 1 (containing oligomers 1 according to the invention with 3 wt. % photoinitiator) was colorless immediately after curing in the 3D printer, and the cured polymer remained colorless even after post-curing in a UV post-curing oven for 2 x 15 minutes (see Figure 1 and Table 2: designation: "without post-curing" or "with post-curing"). The test strips remained colorless even after treatment for 72 h with UV light from a xenon lamp in an artificial weathering device (ATLAS Suntest), and the color / gloss values ​​hardly changed either (see Figure 1 and Table 2: designation: "without post-curing + 72h xenon" or "with post-curing + 72h xenon"). Formulation No. 2 (containing oligomers 1 according to the invention with 1 wt.% photoinitiator) was colorless immediately after curing in the 3D printer and the cured polymer remained colorless even after post-curing in the UV post-curing oven for 2 x 15 minutes (see Figure 1 and Table 2: designation: "without post-curing" or"with post-curing"). The test strips remained colorless even after treatment for 72 hours with UV light from a xenon lamp in an artificial weathering device (ATLAS Suntest), and the color / gloss values ​​hardly changed either (see Figure 1 and Table 2: designation: "without post-curing+72h xenon" or "with post-curing+72h xenon").

[0063] Formulation No. 3 (containing inventive oligomers 2 with 0.01 wt.% dye Blue 30C591) showed only a slight yellowing immediately after curing in the 3D printer, which was due to the slight yellowing of oligomers 2. However, after treatment in the UV post-curing oven for 2 x 15 minutes, a more pronounced discoloration (visible as yellowing in the original) of the cured polymer was visible (see Figure 1 and Table 2: designation: "without post-curing" or "with post-curing"). However, after 72 hours of artificial weathering with UV light from a xenon lamp in an artificial weathering device (ATLAS Suntest), it was found that in both cases a discoloration occurred and both materials showed significantly improved color / gloss values ​​(see Figure 1 and Table 2: designation: "without post-curing + 72h xenon" or "with post-curing + 72h xenon").

[0064] Formulation No. 4 (containing oligomers 2 according to the invention without the dye Blue 30C591) showed only a slightly stronger yellow coloration than formulation No. 3 immediately after curing in the 3D printer, which is due to the slight yellow coloration of the oligomers 2. However, after treatment in a UV post-curing oven for 2 x 15 minutes, a more pronounced discoloration (visible as yellowing in the original) of the cured polymer was noticeable (see Figure 1 and Table 2: designation: "without post-curing" or "with post-curing"). However, after 72 hours of artificial weathering with UV light from a xenon lamp in an artificial weathering device (ATLAS Suntest), it was shown that discoloration occurred in both cases and both materials exhibited significantly improved color / gloss values ​​(see Figure 1 and Table 2: designation: "without post-curing + 72h xenon" or "with post-curing + 72h xenon"). In the case of formulation no. 5 (reference oligomers 3 with 3 wt.-% photoinitiator) a pronounced darkening occurred already after curing in the 3D printer (visible as yellow discoloration in the original), whereby the cured polymer darkened even more after treatment in the UV post-curing oven for 2 x 15 minutes (visible as brown discoloration in the original) (see Figure 1 and Table 2: designation: "without post-curing" or "with post-curing"). After 72 hours of artificial weathering with UV light from a xenon lamp in an artificial weathering device (ATLAS Suntest), both samples darkened further and the color / gloss values ​​also changed significantly (see Figure 1 and Table 2: designation: "without post-curing + 72h xenon" or "with post-curing + 72h xenon").

[0065] In the case of formulation no. 6 (reference oligomer 3 with 1 wt.% photoinitiator), a slight darkening (visible as yellow discoloration in the original) occurred already after curing in the 3D printer, with the cured polymer darkening even more after treatment in the UV post-curing oven for 2 x 15 minutes (visible as brown discoloration in the original) (see Figure 1 and Table 2: designation: "without post-curing" or "with post-curing"). After 72 h of artificial weathering with UV light from a xenon lamp in an artificial weathering device (ATLAS Suntest), both samples darkened further, and the color / gloss values ​​also changed significantly (see Figure 1 and Table 2: designation: "without post-curing + 72h xenon" or "with post-curing + 72h xenon").

[0066] It is suspected that in formulations 5 and 6, residual oligomers are present after curing in the 3D printer. Their methacrylate residues at the end groups are still so reactive that they react with the residual photoinitiator (TPO), which decomposes under normal light, causing the yellowing or browning, respectively. Since oligomers 1 and 2 do not have any methacrylic acid residues (or acrylic acid residues) at their end groups, said oligomers 1 and 2 cannot react with the residual photoinitiator, thus preventing any yellowing or browning. The polymers produced with formulations 1 to 4 therefore remain uncolored even after treatment in the UV post-curing oven. In the case of those prepared from formulations No. 3 and No. 4, discoloration even occurs after 72 hours of artificial weathering with UV light from a xenon lamp in an artificial weathering device (ATLAS Suntest).

Claims

Patent claims Composition for producing a polymer, containing or consisting of: a) oligomers, each containing or consisting of a condensation product of itaconic acid and at least one polyalcohol, wherein the at least one polyalcohol is a dialcohol; b) a reactive diluent selected from the group consisting of acrylic acid ester, methacrylic acid ester, acrylamide, methacrylamide, and combinations thereof; and c) a photoinitiator; characterized in that the oligomers each have no acrylic acid residue and no methacrylic acid residue at their end groups, and the reactive diluent has no isocyanate group. Composition according to the preceding claim, characterized in that the condensation product of the oligomers i) was produced at a temperature of not more than 175°C, preferably not more than 150°C, particularly preferably not more than 130°C; and / or ii) was produced in a nitrogen atmosphere.Composition according to one of the preceding claims, characterized in that the oligomers i) are present in the composition in a concentration of 20 to 80 wt.%, preferably 30 to 70 wt.%, particularly preferably 40 to 60 wt.%, very particularly preferably 45 to 55 wt.%, in particular 48 to 50.9 wt.%, based on the total weight of the composition; and / or. ii) each have a molar mass in the range of 250 to 10000 g / mol, optionally in the range of 1500 to 9500 g / mol, wherein the molar mass refers to a molar mass determinable by size exclusion chromatography.

4. Composition according to one of the preceding claims, characterized in that the dialcohol is selected from the group consisting of saturated aliphatic dialcohols, wherein the saturated aliphatic dialcohol is preferably selected from the group consisting of 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, isosorbide, cyclohexanedimethanol, polyether polyols based on ethylene glycol, 1,3-propanediol and 1,4-butanediol and combinations thereof, wherein the saturated aliphatic dialcohol is in particular selected from the group consisting of neopentyl glycol, 1,6-hexanediol and combinations thereof.

5. Composition according to one of the preceding claims, characterized in that the oligomers each contain or consist of a condensation product of itaconic acid, at least one polyalcohol and at least one polyacid different from itaconic acid, wherein the at least one polyacid different from itaconic acid is a diacid, wherein the diacid is preferably selected from the group consisting of aromatic or saturated aliphatic diacids, wherein the diacid is particularly preferably i) an aromatic diacid selected from the group consisting of phthalic acid, dihydrophthalic acid, tetrahydroxyphthalic acid, hexahydroxyphthalic acid, isophthalic acid, dihydroisophthalic acid, hexahydroisophthalic acid, terephthalic acid, dihydroterephthalic acid, tetrahydroterephthalic acid, hexahydroterephthalic acid, furandicarboxylic acid, dihydrofurandicarboxylic acid, tetrahydrofurandicarboxylic acid, and combinations thereof,wherein the aromatic diacid is in particular phthalic acid; or ii) a saturated aliphatic diacid selected from the group consisting of oxalic acid, malonic acid, succinic acid, Malic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and combinations thereof, wherein the saturated aliphatic diacid is preferably selected from the group consisting of sebacic acid, adipic acid, and combinations thereof. Composition according to one of the preceding claims, characterized in that the reactive diluent i) is present in a concentration of 20 to 80 wt.%, preferably 30 to 70 wt.%, particularly preferably 40 to 60 wt.%, very particularly preferably 45 to 50 wt.%, in particular 46 to 48 wt.%.-%, based on the total weight of the composition, is present in the composition; and / or ii) is selected from the group consisting of hexanediol diacrylate, trimethylolpropane triacrylate, neopentyl glycol diacrylate, acryloylmorpholine, isobornyl acrylate, pentaerythritol triacrylate, hydroxyethyl methacrylate, tricyclodecanedimethanol diacrylate and combinations thereof; and / or iii) does not have a group that is suitable for forming a covalent bond with a carboxyl group during a radical polymerization of the composition and does not have a group that is suitable for forming a covalent bond with a hydroxy group during a radical polymerization of the composition. Composition according to one of the preceding claims, characterized in that the photoinitiator i) is present in a concentration of 0.1 to 6 wt.%, preferably 0.5 to 5 wt.%, furthermore preferably 1.0 to 4.5 wt.%, particularly particularly preferably 2.0 to 4.0 wt.-%, most preferably 2.5 to 3.5 wt.%, based on the total weight of the composition, in the composition; and / or ii) is selected from the group consisting of a-hydroxyketone, a-alkoxyketone, a-aminoketone, acylphosphine oxide, azo compound. and combinations thereof, wherein the photoinitiator is preferably selected from the group consisting of 2-hydroxy-2-methyl-1-phenylpropan-l-one, 1-hydroxy-cyclohexyl-phenyl ketone, a,a-dimethoxy-a-phenylacetophenone, 2-benzyl-2-(dimethylamino)-l-[4-(4-morpholinyl)phenyl]-l-butanone), phenyl-bis(2,4,6-trimethyl-benzoyl)-phosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, azo-bis-(isobutyronitrile) and combinations thereof, wherein the photoinitiator is in particular diphenyl(2,4,6-trimethyl-benzoyl)phosphine oxide. Composition according to one of the preceding claims, characterized in that the composition further contains a polymerization inhibitor, wherein the polymerization inhibitor is preferably i) present in a concentration of >0 to 0.4 wt.%, preferably 0.01 to 0.2 wt.%, particularly preferably 0.02 to 0.1 wt.%, very particularly preferably 0.03 to 0.07 wt.%, in particular 0.05 wt.-%, based on the total weight of the composition, is present in the composition; and / or ii) contains or consists of methoxyphenol and / or 3,5-bis(1,1-dimethylethyl)-4-hydroxytoluene. Composition according to one of the preceding claims, characterized in that the composition further contains or contains no additive selected from the group consisting of pigment, effect pigment, dye, stabilizer, UV absorber, antioxidant, biocide, flow control agent, rheology modifier, defoamer, antistatic agent and combinations thereof. Polymer containing or consisting of: a) covalently bonded via a carbon-carbon bond. Residues of oligomers each containing or consisting of a condensation product of itaconic acid and at least one polyalcohol, wherein the at least one polyalcohol is a dialcohol, and Residues of a reactive diluent selected from the group consisting of acrylic acid ester, methacrylic acid ester, acrylamide, methacrylamide, and combinations thereof; b) a photoinitiator embedded in the polymer; characterized in that the residues of the oligomers each have no acrylic acid residue and no methacrylic acid residue at their end groups, and the residues of the reactive diluent each have no isocyanate group. Polymer according to claim 10, characterized in that it was produced with a composition according to any one of claims 1 to 9. Use of the composition according to any one of claims 1 to 9 for producing a polymer by means of radical polymerization, wherein the polymer is preferably produced in a UV-curing 3D printing process.Use according to claim 12, characterized in that the radical polymerization i) is initiated by irradiating the composition with UV light; and / or ii) is carried out at a temperature of < 40 °C, preferably < 35 °C, particularly preferably < 30 °C, in particular < 25 °C.

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