Radiation curable composition for additive manufacturing process
阅读说明：本技术 用于增材制造方法的可辐射固化组合物 (Radiation curable composition for additive manufacturing process ) 是由 约阿希姆·策希 亨德里克·格鲁普 马尔特·科滕 拉尔夫·佩尔 迪特马尔·布勒斯 焦阿基诺· 于 2018-05-21 设计创作，主要内容包括：本发明涉及用于增材制造方法的可辐射固化组合物,该组合物包含作为组分A1的不包含氨基甲酸酯部分、具有至少1,000的分子量Mw的一种或多种(甲基)丙烯酸酯组分,作为组分B的光引发剂,作为组分C的红色、黄色或橙色染料或它们的组合物,作为组分D的具有在350nm至420nm范围内的光吸收带的蓝色染料,以及任选的作为组分E的稳定剂。本发明进一步涉及在增材制造方法中由可辐射固化组合物生产弹性3维制品的方法,并且涉及获得的弹性3维制品。(The present invention relates to a radiation curable composition for use in an additive manufacturing process, the composition comprising as component a1 one or more (meth) acrylate components not comprising a urethane moiety, having a molecular weight Mw of at least 1,000, as component B a photoinitiator, as component C a red, yellow or orange dye or a combination thereof, as component D a blue dye having a light absorption band in the range of 350nm to 420nm, and optionally as component E a stabilizer. The invention further relates to a method of producing an elastomeric 3-dimensional article from a radiation curable composition in an additive manufacturing process, and to the elastomeric 3-dimensional article obtained.)
1. A radiation curable composition for use in an additive manufacturing process, the composition comprising:
one or more (meth) acrylate components as component A1, said (meth) acrylate components not comprising urethane moieties, having a molecular weight Mw of at least 1,000,
as the photoinitiator of the component B, there is used,
as component C, a red, yellow or orange dye or a combination thereof,
a blue dye as component D, the blue dye having a light absorption band in the range of 350nm to 420nm, and
optionally as a stabilizer for component E.
2. The radiation curable composition according to any of the preceding claims, characterized by any one or combination of more of the following technical features:
viscosity: less than 200Pa s at 23 ℃;
pH value: 6 to 8 when the curable composition is contacted with a wet pH sensitive test paper;
light transmittance: using light having a wavelength of 500, for an optical path length of 1mm, of at least 40%;
radiation curing with light having a wavelength in the range of 350nm to 420 nm;
appearance: is transparent;
color: red, yellow or orange.
3. The radiation curable composition according to any one of the preceding claims, the one or more (meth) acrylate components being characterized by any one or a combination of more of the following technical features:
comprises at least 2 (meth) acrylate moieties;
comprises a polyalkylene oxide backbone;
molecular weight (Mw): 1,000 to 20,000 g/mol;
a polyether backbone comprising the (meth) acrylate moiety attached thereto;
viscosity: from 0.1 pas to 100 pas at 23 ℃.
4. The radiation curable composition according to any of the preceding claims, the red, orange or yellow dye being characterized by a combination of any one or more of the following technical features:
solubility: is soluble in triethylene glycol di (meth) acrylate at 23 ℃;
has a light absorption band in the range of 460nm to 600 nm;
comprising perylene moieties.
5. The radiation curable composition according to any of the preceding claims, the blue dye being characterized by any one or a combination of more of the following technical features:
solubility: is soluble in triethylene glycol di (meth) acrylate at 23 ℃;
comprising a terephthalic acid moiety.
6. The radiation curable composition according to any one of the preceding claims, additionally comprising one or more (meth) acrylate components comprising a urethane moiety as component a2, wherein component a1 is present in higher amounts compared to component a 2.
7. A method of producing an elastic 3-dimensional article, the method comprising the step of processing the radiation curable composition according to any of the preceding claims in an additive manufacturing process comprising a radiation curing step, preferably using light having a wavelength in the range of 350nm to 420 nm.
8. The method according to the preceding claim, the elastic 3-dimensional article having the shape of an orthodontic or dental article, preferably a dental impression.
9. An elastomeric 3-dimensional article comprising the radiation curable composition according to any preceding claim in its cured state.
10. Elastic 3-dimensional article according to the preceding claim, characterized by any one or a combination of the following technical features:
tensile strength: from 0.5MPa to 50MPa according to ISO/DIN 53504 (2015-8);
elongation at break: from 10% to 1000% according to ISO/DIN 53504 (2015-8);
shore A hardness: from 30 to 90 according to ISO/DIN 53505 (2000-8);
light transmittance: when light having a wavelength in the range of 450nm to 600nm is used, the optical path length for 1mm is at least 50%
Water contact angle: less than or equal to 100 degrees;
no tack to the surface of the cured (meth) acrylate;
color: red, orange or yellow.
11. A method of curing a radiation curable composition II comprising the steps of:
a) providing a radiation curable composition I according to any one of claims 1 to 7,
b) curing composition I using radiation processing the radiation curable composition I in an additive manufacturing process to obtain a transparent elastomeric 3-dimensional article having an outer side and an inner side,
c) placing a radiation curable composition II on the inside of the transparent 3-dimensional article,
d) photocuring the radiation curable composition II from the outside of the transparent 3-dimensional article,
the radiation curable composition II is different from the radiation curable composition I.
12. The method of claim 11, wherein the curing in step b) and step d) is performed at different wavelengths.
13. The method according to claim 11 to 12,
the radiation curing step b) is carried out at a wavelength in the range of 350nm to 420nm,
the radiation curing step d) is carried out at a wavelength in the range of from 430nm to 500 nm.
14. The method according to claims 11 to 13, the radiation curable composition II being selected from a dental cement, a dental adhesive or a dental composite.
15. A kit comprising
A radiation curable composition I according to any one of claims 1 to 7, and
a radiation curable composition II which differs from the radiation curable composition I in its chemical composition and is radiation curable within a wavelength in the range of 430nm to 500 nm.
Technical Field
The present invention relates to a radiation curable composition useful in an additive manufacturing process.
The radiation curable composition is especially useful for producing transparent and elastic 3-dimensional articles, which 3-dimensional articles can further be used e.g. in the dental and orthodontic field, e.g. for fixing brackets.
Background
In orthodontic treatment, brackets must be placed accurately on the patient's teeth. For this reason, so-called positioning brackets may be a useful tool.
Such positioning trays or transfer trays essentially consist of an impression of the patient's jaw with a mould at those locations where the brackets are positioned. Thus, brackets may be placed into these molds and thus transferred into the patient's mouth.
When such a dental tray comprising brackets is placed in the mouth of a patient, the brackets are automatically positioned accurately on the teeth.
Such procedures are described, for example, in the background section of US2015/0313687A1(Blees et al).
These trays are typically made in a time consuming process that begins with a model of the patient's mouth on which the brackets are placed.
It begins with the manufacture of a model of the patient's jaw and the positioning of brackets on the lingual side of the tooth model.
The housing is then manufactured by applying a shim on the former and vacuum forming a deep-drawn foil on the shim.
The shim is then removed and the shell is filled with a clear heat curable silicone so that the shell acts like an impression tray.
The casing with the mixed silicone paste is then placed back on the mold and heat cured.
This causes the silicone to set, forming a transparent and resilient inner shell that can be machined to receive the bracket. A picture of such a transparent positioning tray is shown in fig. 1.
During use, the transparent positioning tray contains all of the brackets on the lingual side of the teeth in the patient's mouth.
In the next step, the orthodontist can place all brackets in the patient's jaw at once using the transparent positioning tray, which saves time and makes bracket placement accurate.
The brackets typically contain a layer of adhesive or cement on their surface that the orthodontist light-cures.
This means that after placing the transparent positioning tray with the brackets in the patient's mouth, the doctor cures the adhesive located on the brackets by using conventional dental curing light through the material of the transparent positioning tray.
Light is applied such that the light passes through the outer shell and the inner shell until the bracket is secured to the lingual surface of the tooth.
It is clear that although positive results can be obtained by following this method, a simplified method is still needed.
US 6,855,748(Hatton) describes UV curable compositions comprising oxetane and epoxy compounds in combination with polyfunctional hydroxy compounds which may comprise additional (meth) acrylates and which may be used in laser induced stereolithography processes.
US 2014/0035202 a1(Southwell et al) describes radiation curable resin compositions and fast 3-dimensional imaging methods using these compositions. These resins are based on the combination of cycloaliphatic epoxides with oxetanes and (meth) acrylates and cationic and free-radical photoinitiators.
One suitable class of free radical photoinitiators includes ionic dye-counter ion compounds that are capable of absorbing actinic radiation and generating free radicals.
WO 2014/078537 a1 (dentspray) describes A3-dimensional manufacturing material system for producing dental products, such as artificial teeth, dentures, splints, veneers, inlays, onlays, coping, framework styles, crowns, bridges, etc. A DLP process was used.
The material is a (meth) acrylate based material and may comprise a pigment.
WO 2015/073301 a1(Chang) relates to 3-dimensional color printing, for example by SLA, to produce 3-dimensional printed coloured multicoloured parts, but without treatment of the dye to avoid over-curing.
US 2007/0205528 a1(Patel et al) and US 2007/0256781a1(Johnson et al) describe photocurable compositions for rapid prototyping techniques which may contain dyes but which do not address detail resolution issues.
WO 2014/078537 a1(Sun et al) describes a three-dimensional manufacturing material system for producing dental products. The composition for producing a three-dimensional dental prosthesis comprises a mixture of a (meth) acrylate, an inorganic filler, an organic filler, a silicone-acrylic based rubber impact modifier, a pigment and a photoinitiator.
WO 2013/153183A 2(Wachter et al) describes a composite resin composition and a method for producing dental components by stereolithography. The composite resin composition comprises a) at least one polymeric binder, b) a first photopolymerization initiator having an absorption maximum at a wavelength of less than 400nm, c) a second photopolymerization initiator having an absorption maximum of at least 400nm, and d) an absorber having an absorption maximum at a wavelength of less than 400nm for SLA production of a composite resin based dental moulding component.
US 2008/0287564 a1(Klare et al) describes biocompatible, low-viscosity radiation-curable formulations for the production of medical products, in particular adaptive earpieces, shells or ear parts, by the PNP process or the stereolithography process, wherein the critical energy of the penetration depth is adjusted by the addition of small amounts of anaerobic inhibitors such as phenothiazine or DPPH.
US 2014/0072712 a1(Xu) describes opaque inks for use with three-dimensional printing systems comprising 10-95 wt% of a polymerizable component and 3-25 wt% of a non-reactive wax component.
Disclosure of Invention
There is a need for a radiation curable composition that can be processed in additive manufacturing techniques, especially using stereolithography 3-dimensional printing methods, to obtain transparent elastomeric 3-dimensional articles with high surface resolution.
In particular, the radiation curable composition should be suitable for producing elastic 3-dimensional articles that can be used in the dental or orthodontic field.
Furthermore, there is sometimes a need to increase the possibilities of inspecting and/or controlling the production of 3-dimensional articles in 3-dimensional printing methods.
Furthermore, the radiation curable composition should be able to produce a so-called transparent positioning tray (CPT), if possible, from data obtained, for example, from an intraoral scan of the dental condition in a patient's mouth.
Such transparent positioning trays should be sufficiently elastic, translucent, especially in the region of 420nm to 500nm, and should be easily removable from other dental or orthodontic appliances and materials like dental adhesives or dental cement compositions comprising (meth) acrylate components.
One or more of the above objects may be achieved by the invention described herein.
In one embodiment, the present invention is technically characterized by a radiation curable composition I as claimed in the claims and described herein, comprising:
one or more (meth) acrylate components, which do not contain urethane moieties, preferably having a molecular weight Mw of at least 1,000,
-a photo-initiator,
-a red, orange, yellow dye or a combination thereof,
a blue dye showing an absorption band in the range of 350 to 420nm,
-optionally a stabilizer.
In another embodiment, the invention relates to a method for producing a transparent elastomeric 3-dimensional article according to the claims and as described herein by processing a radiation curable composition I in an additive manufacturing process comprising a radiation curing step.
The present invention also relates to a transparent elastomeric 3-dimensional article obtained by radiation curing a radiation curable composition I as defined in the claims and herein.
Another aspect of the present invention relates to a kit comprising a radiation curable composition I and a radiation curable composition II as claimed in the claims and described herein.
The present invention also relates to a process for curing a radiation curable composition B by irradiating light through a cured elastomeric 3-dimensional article obtained from the radiation curable composition I.
Unless defined differently, for purposes of this specification, the following terms shall have the given meanings:
a "hardenable component or material" or "polymerizable component" is any component that can be cured or hardened by radiation-induced polymerization in the presence of a photoinitiator. The hardenable component may comprise only one, two, three, or more polymerizable groups. Typical examples of polymerizable groups include unsaturated carbon groups such as vinyl groups present in particular in (meth) acrylate groups.
A "photoinitiator" is a substance capable of initiating or initiating the curing process of a hardenable composition in the presence of radiation, in particular in the presence of light (wavelength of 300nm to 700 nm).
A "monomer" is any chemical species characterized by a chemical formula with polymerizable groups (including (meth) acrylate groups) that can be polymerized into oligomers or polymers to increase molecular weight. The molecular weight of the monomers can generally be calculated simply on the basis of the given chemical formula.
As used herein, "(meth) acryloyl" is a shorthand term that refers to "acryloyl" and/or "methacryloyl". For example, a "(meth) acryloxy" group is a shorthand term that refers to an acryloxy group (i.e., CH)2(ii) a ═ CH-C (O) -O-) and/or methacryloxy group (i.e., CH2＝C(CH3) Any one of-C (O) -O-).
"curing, hardening, or setting reaction" is used interchangeably and refers to a reaction in which the physical properties of the composition (e.g., viscosity and hardness) change over time due to chemical reactions between the individual components.
The term "dental or orthodontic article" means any article to be used in the dental or orthodontic field, in particular any article used for producing dental restorations, orthodontic devices, tooth models and their components.
Examples of dental articles include crowns, bridges, inlays, onlays, veneers, braces, coping, crowns and bridge frames, implants, abutments, milling pieces, single piece dental restorations, and components thereof.
Examples of orthodontic articles include brackets, buccal tubes, splints and buttons and components thereof.
The dental or orthodontic article should not contain components that are harmful to the health of the patient and therefore not contain components that can migrate out of the dental or orthodontic article that are hazardous and toxic.
A "transparent article" is an article that is transparent under human eye observation, particularly an article having a light transmission of at least 40% for light having a wavelength of 500nm for an optical path length of 1 mm.
Thus, the picture can be seen through a thin sheet (1mm thick) of such transparent material.
A "red dye" is a dye that has a red appearance in the human eye.
A "yellow dye" is a dye that has a yellow appearance in the human eye.
An "orange dye" is a dye that has an orange appearance in the human eye.
By "additive manufacturing" or "3-dimensional printing" is meant a process that includes a radiation curing step for making a 3-dimensional article. One example of an additive manufacturing technique is Stereolithography (SLA), where successive layers of material are laid down under computer control. The article can have virtually any shape or geometry and be produced from a 3-dimensional model or other source of electronic data.
By "ambient conditions" is meant the conditions to which the compositions described herein are typically subjected during storage and handling. The ambient conditions may be, for example, a pressure of 900mbar to 1100mbar, a temperature of 10 ℃ to 40 ℃ and a relative humidity of 10% to 100%. Ambient conditions are usually adjusted in the laboratory to 20 ℃ to 25 ℃ and 1000 mbar to 1025 mbar.
A composition is "substantially or substantially free of" a component if the composition does not contain that component as an essential feature. Thus, the components are not optionally added to the composition or combined with other components or ingredients of other components. Compositions that are substantially free of a component typically do not contain that component at all. However, the presence of small amounts of said components is sometimes unavoidable, for example due to impurities contained in the raw materials used.
As used herein, "a," "an," "the," "at least one," and "one or more" are used interchangeably. The terms "comprise" or "contain" and variations thereof do not have a limiting meaning when they appear in the description and claims. Also herein, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).
The addition of plural forms to terms means that the terms shall include both singular and plural forms. For example, the term "additive" means one additive and more additives (e.g., 2, 3, 4, etc.).
Unless otherwise indicated, all numbers expressing quantities of ingredients, measurements of physical properties as described below, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about".
The term "comprising" shall also include the terms "consisting essentially of and" consisting of.
Drawings
Figure 1 shows a picture of a transparent positioning tray according to the state of the art.
Fig. 2 shows a picture of a test sample obtained from the colored radiation curable composition described herein.
Fig. 3 shows a picture of a test specimen obtained from a colorless radiation curable composition.
Fig. 4 shows a picture of a transparent positioning tray obtained from the colored radiation curable composition described herein.
Detailed Description
It has been found that the compositions described herein have several advantageous properties.
The radiation curable composition I described herein can be processed as a manufacturing material in an additive manufacturing process, in particular a so-called SLA process.
Due to the presence of red, orange or yellow dyes, especially fluorescent dyes, the production of 3-dimensional articles in the additive manufacturing process can easily be checked by e.g. using blue light.
Furthermore, the radiation curable composition I described herein helps to solve different problems.
In additive manufacturing processes, especially in SLA processes, the problem of "overcuring" has to be solved. This means that the detail accuracy of the light-induced polymerisation may be less than satisfactory, as polymerisation occurs not only in the regions exposed to light, but also in a slightly wider region, resulting in a loss of detail accuracy in the additive manufacturing process.
It has been found that the use of a red, orange or yellow dye in combination with a blue dye as described herein helps to produce good printing accuracy in the additive manufacturing process, resulting in a coloured elastic article with good resolution of details.
Such elastomeric articles should also be sufficiently transparent to allow transmission of light in the wavelength range typically used in the dental field for curing radiation curable dental adhesives or dental cements.
This is particularly useful in the orthodontic field because it enables the radiation of a dental adhesive or cement to be positioned on the surface of an orthodontic bracket, for example in a transparent positioning tray.
As suggested herein, the combination of a blue dye and another dye selected from a red dye, an orange dye and/or a yellow dye also satisfies this need.
The elastomeric articles obtained by curing the radiation curable composition I described herein are sufficiently transparent in the wavelength range of 420nm to 500 nm.
Furthermore, the elastomer obtained after curing the radiation curable composition I and used for radiation curing another radiation curable composition should be easily removable from the other radiation curable composition after curing.
It has also been found that the elastic 3-dimensional articles obtained from the curable compositions described herein do not stick to the surface of other (meth) acrylate containing compositions. That is, the elastomeric 3-dimensional article can be easily removed from the surface of a (meth) acrylate composite article or composition, including dental adhesives and dental cements.
This is surprising because both the elastic 3-dimensional article and the (meth) acrylate composite article are based on the same crosslinking chemistry.
Conversely, it would be desirable to position the curing of a radiation curable (meth) acrylate composition on the surface of another (meth) acrylate article that would result in adhesion of the radiation curable (meth) acrylate composition to the other (meth) acrylate article.
According to a preferred embodiment, the present invention allows a dental composition (such as an adhesive or cement) to be photocured by passing light through an elastic transparent 3-dimensional article obtained by curing the radiation curable composition I described herein and then removing the elastic transparent 3-dimensional article.
To our knowledge, there is no commercially available SLA resin available so far that exhibits good elastic properties (e.g. good elastic recovery and good elongation at break) after additive manufacturing processes.
Thus, the radiation curable composition I described herein is particularly useful for making transparent positioning trays. Transparent positioning trays can now be produced more easily.
Furthermore, in addition to its use in the orthodontic or dental field, the invention also provides a solution for any procedure requiring a 3-dimensionally printable composition, in which a photocuring process should be done by the 3-dimensionally printable composition, for example in order to shape, fix or cure any component in the manufacturing process chain.
The transparent elastomeric 3-dimensional printed articles obtained from the radiation curable composition I described herein may also be used for the production of technical parts, such as fittings, bumpers, seals and the like.
The present invention relates to a radiation curable composition I for use in an additive manufacturing process comprising a radiation curing step.
In certain embodiments, the radiation curable compositions I described herein generally satisfy a combination of any one or more of the following characteristics:
a) viscosity: less than 200Pa s at 23 ℃;
b) pH value: 6 to 8 when the curable composition is contacted with a wet pH sensitive test paper;
c) light transmittance: using light having a wavelength of 500nm, the optical path length for 1mm is at least 40%;
d) radiation curing with light having a wavelength in the range of 350nm to 420 nm;
e) appearance: is transparent;
f) color: red, orange or yellow.
In certain embodiments, combinations of the following technical features are sometimes desired: a) c) and d) or e) and f).
The radiation curable composition I described herein comprises one or more (meth) acrylate components which do not comprise a urethane moiety as component a 1.
The nature and structure of component a1 is not particularly limited unless the desired result cannot be achieved.
Component a1 can be characterized by any one or a combination of more of the following technical features:
a) comprises at least 2 or 3 or 4 (meth) acrylate moieties;
b) comprises a polyalkylene oxide backbone;
c) molecular weight (Mw): 1,000 to 20,000 g/mol; or 2,000g/mol to 15,000 g/mol; or 3,000g/mol to 10,000 g/mol;
d) a polyether backbone comprising attached (meth) acrylate moieties;
e) viscosity: from 0.1 to 100 or from 1 to 50 pas at 23 ℃.
The combination of the technical features a) and b), or a), b) and c), or a), d) and e) may sometimes be preferred.
According to one embodiment, component a1 comprises a polyalkylene oxide backbone having attached at least two (meth) acrylate moieties.
Such components are suitable for the production of rubber-elastic compositions.
The average molecular weight (Mw) of component a1 is typically in the range of 1,000 to 20,000.
Molecular weights within this range may contribute to improved properties such as elasticity, elongation at break, Young's modulus, and/or elastic modulus.
Suitable methods for measuring the molar mass of reactive end groups, for example polyalkylene oxides containing OH groups, include titration of the end groups.
Preferred representatives of component A1 include
R-[(CH2)n-(CHR')-O]k-[(CH2)m-(CHR”)-O]l-(CH2)m-(CHR”)-R
Wherein:
n is 1 to 6, preferably 1 to 4, especially 1;
m is 1 to 6, preferably 1 to 4, especially 3;
k. 2 to 500, preferably 4 to 250, especially 10 to 200;
r ', R "are independently selected from H, methyl, ethyl, preferably R' ═ R" H,
R＝CH2(O) -O-or CH2＝C(CH3)-C(O)-O-，
The expression in square brackets, indexed by the symbols k and l, can be arranged regularly or irregularly, in alternating form or in blocks.
Suitable polyethers or polyether groups which can form the polyalkylene oxide backbone of component a1 can be produced in a manner known to the person skilled in the art, for example by reaction of a starter compound having active hydrogen atoms with alkylene oxides, for example ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran or epichlorohydrin or mixtures of two or more thereof.
Particularly suitable are polyether compounds obtainable by polyaddition of ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide or tetrahydrofuran or mixtures of two or more of the compounds mentioned with the aid of suitable starting compounds and suitable catalysts.
The reaction products of low molecular weight polyfunctional alcohols having at least two hydroxyl groups with alkylene oxides, so-called polyethers, can also be used as polyols. The alkylene oxide preferably has 2 to 4 carbon atoms. Suitable polyols are, for example, the reaction products of ethylene glycol, propylene glycol, butylene glycol or hexylene glycol isomers with one or more of the following alkylene oxides: ethylene oxide, propylene oxide or butylene oxide such as tetrahydrofuran. Furthermore, the reaction product of a polyfunctional alcohol (e.g. glycerol, trimethylolethane or trimethylolpropane, pentaerythritol or a sugar alcohol, or a mixture of two or more thereof) with said alkylene oxide forms a polyether polyol, which are also suitable.
Suitable starting compounds are, for example: water, ethylene glycol, 1, 2-or 1, 3-propanediol, 1, 4-or 1, 3-butanediol, 1, 6-hexanediol, 1, 8-octanediol, neopentyl glycol, 1, 4-hydroxymethyl-cyclohexane, 2-methyl-1, 3-propanediol, glycerol, trimethylolpropane, 1,2, 6-hexanetriol, 1,2, 4-butanetriol, trimethylolethane, pentaerythritol, mannitol, sorbitol, or a mixture of two or more thereof.
Particularly suitable are polyether compounds obtained by polyaddition of ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide or tetrahydrofuran or mixtures of two or more of the mentioned compounds with the aid of suitable starting compounds and suitable catalysts.
For example, polyether polyols prepared by copolymerization of tetrahydrofuran and ethylene oxide in a molar ratio of from 10:1 to 1:1, preferably 4:1, in the presence of strong acids, such as boron trifluoride etherate, are also suitable.
Specific examples of component a1 include (meth) acrylated ethylene oxide, propylene oxide, ethylene oxide/propylene oxide copolymers, ethylene oxide/tetrahydrofuran copolymers, polypropylene glycol, and mixtures thereof.
Component a1 is typically present in the following amounts:
-a lower limit: at least 50 wt%, or at least 55 wt%, or at least 60 wt%;
-an upper limit: at most 95 wt%, or at most 90 wt%, or at most 85 wt%;
-a range: 50 to 95 wt.%, or 55 to 90 wt.%, or 60 to 85 wt.%;
the weight% is relative to the total composition.
According to one embodiment, the radiation curable composition I further comprises a (meth) acrylate component having a urethane moiety as component a 2.
The addition of a (meth) acrylate component having a urethane moiety can help to improve the physical properties of the cured composition, such as flexural strength and/or elongation at break.
Component a2 can be characterized by any one or a combination of more of the following technical features:
a) comprises at least 2 or 3 or 4 (meth) acrylate moieties;
b) molecular weight (Mw): 200g/mol to 1,000g/mol or 300g/mol to 800 g/mol;
c) comprises C1To C20A linear or branched alkyl moiety to which a (meth) acrylate moiety is attached through a urethane moiety;
d) viscosity: from 0.1 to 100 or from 1 to 50 pas at 23 ℃.
Combinations of the technical features a) and b), or b) and c), or a) and d) may sometimes be preferred.
Urethane (meth) acrylates can be obtained by various methods known to the skilled person.
Urethane (meth) acrylates are typically obtained by reacting NCO-terminated compounds with suitable monofunctional (meth) acrylate monomers such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, preferably hydroxyethyl acrylate and hydroxypropyl methacrylate.
For example, a polyisocyanate and a polyol may be reacted to form an isocyanate-terminated urethane prepolymer, which is subsequently reacted with a (meth) acrylate such as 2-hydroxyethyl (meth) acrylate. These types of reactions can be carried out at room temperature or higher, optionally in the presence of a catalyst such as a tin catalyst, a tertiary amine, or the like.
The polyisocyanate useful in forming the isocyanate functional urethane prepolymer can be any organic isocyanate having at least two free isocyanate groups. Including aliphatic, cycloaliphatic, aromatic and araliphatic isocyanates.
Any known polyisocyanate may be used, such as alkyl and alkylene polyisocyanates, cycloalkyl and cycloalkylene polyisocyanates, and combinations such as alkylene and cycloalkylene polyisocyanates.
Preferably, compounds having the formula X (NCO)2Wherein X represents an aliphatic hydrocarbon group having 2 to 12C atoms, a cycloaliphatic hydrocarbon group having 5 to 18C atoms, an aromatic hydrocarbon group having 6 to 16C atoms and/or an araliphatic hydrocarbon group having 7 to 15C atoms.
Examples of suitable polyisocyanates include 2,2, 4-trimethylhexamethylene-1, 6-diisocyanate, hexamethylene-1, 6-diisocyanate (HDI), cyclohexyl-1, 4-diisocyanate, 4' -methylene-bis (cyclohexyl isocyanate), 1' -methylenebis (4-isocyanato) cyclohexane, isophorone diisocyanate, 4' -methylenediphenyl diisocyanate, 1, 4-tetramethylene diisocyanate, m-and p-tetramethylxylene diisocyanate, 1, 4-phenylene diisocyanate, 2, 6-and 2, 4-toluene diisocyanate, 1, 5-naphthylene diisocyanate, 2,4 '-diphenylmethane diisocyanate and 4,4' -diphenylmethane diisocyanate and mixtures thereof.
Higher functional polyisocyanates or other modified polyisocyanates known from polyurethane chemistry, such as those containing carbodiimide groups, allophanate groups, isocyanurate groups and/or biuret groups, may also be used. Particularly preferred isocyanates are isophorone diisocyanate, 2,4, 4-trimethyl-hexamethylene diisocyanate and higher functional polyisocyanates having an isocyanurate structure.
The isocyanate-terminated urethane compound is terminated with a (meth) acrylate to produce a urethane (meth) acrylate compound. Generally, any (meth) acrylate-type capping agent having a terminal hydroxyl group and also having an acrylic or methacrylic moiety, with methacrylic moieties being preferred, can be used.
Examples of suitable capping agents include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, glycerol di (meth) acrylate, and/or trimethylolpropane di (meth) acrylate. Particularly preferred are 2-hydroxyethyl methacrylate (HEMA) and/or 2-hydroxyethyl acrylate (HEA).
The equivalent ratio of isocyanate groups to compounds reactive with isocyanate groups is from 1.1:1 to 8:1, preferably from 1.5:1 to 4: 1.
The isocyanate polyaddition reaction may be carried out in the presence of catalysts known from polyurethane chemistry, for example organotin compounds such as dibutyltin dilaurate or amine catalysts such as diazabicyclo [2.2.2] octane. Furthermore, the synthesis can be carried out in the melt or in a suitable solvent, which can be added before or during the preparation of the prepolymer. Suitable solvents are, for example, acetone, 2-butanone, tetrahydrofuran, dioxane, dimethylformamide, N-methyl-2-pyrrolidone (NMP), ethyl acetate, alkyl ethers of ethylene glycol and propylene glycol, and aromatic hydrocarbons. Particular preference is given to using ethyl acetate as solvent.
Suitable examples of urethane (meth) acrylates include 7,7, 9-trimethyl-4, 13-dioxo-3, 14-dioxa-5, 12-diazahexadecane-1, 16-dioxo-dimethacrylate (e.g.Plex 666-1, B,
Suitable urethane dimethacrylates may be characterized, for example, by the formula:
wherein
R1Is a hydrogen atom or a methyl group; and is
R2Is a linear or branched alkylene radical having from 1 to 8 carbon atoms or
Specific examples of component a2 also include bis (acryloyloxyethyl) dimethylene dicarbamate, bis (methacryloyloxyethyl) -dimethylene dicarbamate, bis (acryloyloxyethyl) tetramethylene dicarbamate, bis (methacryloyloxyethyl) -tetramethylene dicarbamate, bis (acryloyloxyethyl) -trimethylhexamethylene dicarbamate, and bis (methacryloyloxyethyl) -trimethylhexamethylene dicarbamate, and mixtures thereof.
According to one embodiment, urethane dimethacrylate having the following formula is preferred:
other suitable urethane (meth) acrylates that may be present in the radiation curable compositions described herein are characterized as follows:
-having the structure A- (-S1-U-S2-MA)nWherein
A is a connecting element comprising at least one cell,
-S1 is a spacer group comprising at least 4 units linked to each other,
-S2 is a spacer group comprising at least 4 units linked to each other,
units of-A, S1 and S2 are independently selected from CH3-、-CH2-、-O-、-S-、-NR1-、-CO-、-CR1＝、
Wherein R is1And R2Independently selected from hydrogen, alkyl, substituted alkyl, alkenyl, cycloalkyl, substituted cycloalkyl, aralkyl, aryl or substituted aryl, wherein these units may form a linear, branched or cyclic structure, such as an alkyl, cycloalkyl, aryl, ester, carbamate or amide group,
u is a carbamate group linking the spacer groups S1 and S2,
MA is an acrylate or methacrylate group, and
-n is 3 to 6.
According to one embodiment, the urethane (meth) acrylate is represented by the following structure
A-(-S1-U-S2-MA)n
Wherein
-A is a connecting element comprising at least 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 units,
s1 is a spacer group consisting of units linked to one another and comprising at least 4, 5, 6, 7, 8, 9 or 10 units,
-S2 is a spacer group consisting of units linked to each other and comprising at least 4, 5, 6, 7, 8, 9, 10, 12, 15, 20 or 25 units,
u is a carbamate group linking the spacer groups S1 and S2,
MA is an acrylate or methacrylate group, and
-n is 3 to 6 or 4 to 6 or 5 to 6.
It may be preferred if a has a cyclic structure and comprises at least 6 units.
It may be further preferred if S1 has a linear or branched structure and comprises at least 4 or 6 units.
It may be further preferred if S2 has a linear or branched structure and comprises at least 6 or 8 units.
Urethane (meth) acrylates in which a has a cyclic structure and comprises at least about 6 units, and S1 has a linear structure and comprises at least 4 units, and S2 has a linear structure and comprises at least 8 units, and U is a urethane group may also be preferred.
Neither the atom of the urethane group nor the atom of the (meth) acryloyl group connecting S1 and S2 belongs to the spacer group S1 or S2. Thus, the atoms of the carbamate group are not counted as units of the spacer group S1 or S2.
The nature and structure of the connecting element is not particularly limited. The linking element may contain saturated (no double bonds) or unsaturated (at least one or two double bonds) units, aromatic or heteroaromatic units (aromatic structures containing atoms including N, O and S).
Specific examples of the connecting member a having a ring structure include:
specific examples of the connecting element a having a non-cyclic but branched structure include:
the dashed line indicates the bond to the spacer group S1.
The nature and structure of the spacer group S1 or S2 is also not particularly limited.
The spacer group is composed of units linked to each other. A typical cell includes: CH (CH)3-、-CH2-、-O-、-S-、-NR1-、-CO-、-CR1＝、
These units may form linear, branched, or cyclic structures, such as alkyl, cycloalkyl, aryl, ester, carbamate, or amide groups.
The structure of S1 may be the same as that of S2. However, in some embodiments, the structure of S1 is different from the structure of S2. In a specific embodiment, the number of units present in S1 is less than or equal to the number of units present in S2.
In a particular embodiment, S1 may have a saturated hydrocarbon structure.
In another specific embodiment, S2 may have a saturated hydrocarbon structure.
Typical examples of useful spacer groups for S1 include:
the dotted line represents a chemical bond to group a or group U.
Typical examples of useful spacer groups for S2 include:
the dashed line indicates a chemical bond to a (meth) acrylate group or group U. The number of units counted according to the invention is given in parentheses.
Specific examples of the hardenable component (B) include
Further suitable urethane (meth) acrylates are based on α, omega-terminated poly (meth) acrylate diols (e.g. as described in EP 1242493B 1), or may be polyester, polyether, polybutadiene or polycarbonate urethane (meth) acrylates (e.g. as described in US 6,936,642B 2).
Component a2, if present, is typically present in the following amounts:
-a lower limit: at least 1 wt%, or at least 5 wt%, or at least 10 wt%;
-an upper limit: at most 40 wt.%, or at most 35 wt.%, or at most 30 wt.%;
-a range: 1 to 40 wt%, or 5 to 35 wt%, or 10 to 30 wt%;
the weight% is relative to the total composition.
According to one embodiment, the radiation curable composition comprises component a1 and component a2, wherein component a1 is present in an amount exceeding component a 2.
The molecular weight of component A2 is generally lower than the molecular weight of component A1.
The radiation curable compositions I described herein comprise one or more photoinitiators as component B.
Or the nature and structure of the photoinitiator is not particularly limited unless the desired result cannot be achieved.
The photoinitiator may be characterized by any one or a combination of more of the following technical features:
-shows a light absorption band in the wavelength range of 300nm to 450nm, preferably in the range of 380nm to 420 nm;
-solubility: at 23 ℃ of at least 2g in 100g of triethylene glycol di (meth) acrylate (TEGDMA).
Photoinitiators typically absorb light in the blue spectral range, for example in the range of 350nm to 450 nm.
The photoinitiator should be soluble in the radiation curable components of the curable resin compositions described herein.
The photoinitiator is capable of generating free radicals for polymerization upon exposure to light energy having a wavelength between 350nm and 450 nm.
The following classes of photoinitiators have been found to be particularly useful: a component system in which two radicals are generated by cleavage.
Examples of photoinitiators according to this type generally contain a moiety selected from benzoin ether, acetophenone, benzoyl oxime or acyl phosphine.
One particularly suitable class of photoinitiators comprises the class of acylphosphine oxides as described in US patent US 4,737,593 (ellich et al).
Such acylphosphine oxides have the formula
(R9)2—P(＝O)—C(＝O)—R10
Wherein each R9May be independently a hydrocarbyl group such as alkyl, cycloalkyl, aryl and aralkyl, any of which may be substituted with halogen, alkyl or alkoxy groups, or two R9The group may be joined to form a ring with the phosphorus atom, and wherein R10Is a hydrocarbyl group, a five-or six-membered heterocyclic group containing S-, O-, or N-, or-Z-C (═ O) -P (═ O) - (R)9)2A group wherein Z represents a divalent hydrocarbon group such as a hydrocarbylene group or a phenylene group having 2 to 6 carbon atoms.
Preferred acylphosphine oxides are those wherein R is9And R10Groups are those of phenyl or lower alkyl-or lower alkoxy-substituted phenyl. "lower alkyl" and "lower alkoxy" mean such groups having 1 to 4 carbon atoms.
Exemplary UV initiators include 1-hydroxycyclohexyl benzophenone (e.g., under the trade designation "IRGACURETM184 "from Ciba Specialty Chemicals Corp., Tarrytown, NY), 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (e.g., under the trade designation" IRGACURETM2529 "available from Ciba specialty Inc.), 2-hydroxy-2-methylpropiophenone (e.g., under the trade designation" DAROCURETMD111 "from Ciba specialty Chemicals), and bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide (e.g., under the trade name" IRGACURETM819 "from Ciba specialty Chemicals).
Most preferably, the acylphosphine oxide is bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide (IRGACURE)TM819, Ciba specialty Chemicals, Tariden, N.Y.).
The tertiary amine reducing agent may be used in combination with the acylphosphine oxide. Exemplary tertiary amines include ethyl 4- (N, N-dimethylamino) benzoate and N, N-dimethylaminoethyl methacrylate.
Commercially available phosphine oxide photoinitiators capable of free radical initiation when irradiated at wavelengths greater than 400nm to 1200nm include a mixture of bis (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one (IRGACURE) in a weight ratio of 25:75TM1700 Ciba refining Co.), 2-benzyl-2- (N, N-dimethylamino) -1- (4-morpholinylphenyl) -1-butanone (IRGACURE)TM369 Ciba Georgi), bis (η 5-2, 4-cyclopentadien-1-yl) -bis (2, 6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium (IRGACURE)TM784Dc, Ciba specialty Chemicals), a mixture of bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR) in a weight ratio of 1:1TM4265 available from Ciba specialty Chemicals), and ethyl-2, 4, 6-trimethylbenzylphenylphosphinate (LUCIRIN)TMLR8893X, BASF corp, Charlotte, NC, Charlotte, north carolina.
Also useful are photoinitiators comprising α trione-based moieties or α diketodialkyl ketal moieties.
The photoinitiator is typically present in the following amounts:
-a lower limit amount: at least 0.01 wt%, or at least about 0.05 wt%, or at least about 0.1 wt%;
-an upper limit amount: at most 5 wt.%, or at most 3 wt.%, or at most 2 wt.%;
-a range: 0.01 to 5 wt.%, or 0.01 to 3 wt.%, or 0.01 to 2 wt.%;
the weight% is relative to the weight of the entire composition.
The radiation curable compositions described herein comprise as component C one or more red, orange, yellow dyes or combinations thereof.
The nature and structure of component C is not particularly limited unless the desired result cannot be achieved.
The red dye has a light absorption band in the wavelength range of 550nm to 600nm, preferably showing a light absorption maximum.
The orange dye has a light absorption band in the wavelength range of 480nm to 550nm, preferably showing a light absorption maximum.
The yellow dye has a light absorption band in the wavelength range of 460nm to 480nm, preferably showing a light absorption maximum.
The dye may also be a red, orange or yellow fluorescent dye, i.e. a dye that shows fluorescence if illuminated by light.
According to one embodiment, component C may be characterized by any one or a combination of more of the following technical features:
a) solubility: at least 0.1g of triethylene glycol di (meth) acrylate (TEGDMA) in 100g at 23 ℃;
b) has a light absorption band in the range of 460nm to 600nm,
c) having a fluorescence band in the range of 500nm to 650nm,
d) comprising perylene moieties.
The combination of the technical features a) and b), or a), b) and c), or a), b), c) and d) may sometimes be preferred.
The addition of red, orange or yellow dyes as described herein can help to improve printing accuracy, especially in terms of surface detail.
Furthermore, it may be advantageous if the red, orange or yellow dye absorbs light in the range of 380nm to 420 nm. Such light absorption may further contribute to good printing accuracy.
In particular, the presence of dyes showing fluorescence in the human visible spectrum enables the 3-dimensional article to be easily inspected and controlled in additive manufacturing processes (especially in SLA processes).
Suitable examples of red dyes include Lumogen having an absorption maximum at 575nmTMF Red 300 (BASF) and fluorozenitrot 94720 (Kremer).
A suitable example of an orange dye is fluorozenzorange 94738 (kramer) having an absorption maximum at 526 nm.
A suitable example of a yellow dye is fluorozenzgelb 94700 (kramer) having an absorption maximum at 474 nm.
The red dye is typically present in the following amounts:
-a lower limit: at least 0.001 wt%, or at least 0.003 wt%, or at least 0.005 wt%;
-an upper limit: at most 1 wt%, or at most 0.5 wt%, or at most 0.1 wt%;
-a range: 0.001 to 1 wt.%, or 0.003 to 0.5 wt.%, or 0.005 to 0.1 wt.%;
the weight% is relative to the total composition.
The radiation curable compositions described herein comprise one or more blue dyes as component D.
Or the nature and structure of component D is not particularly limited unless the desired result is not achieved.
The blue dye may also be a blue fluorescent dye, i.e. a red dye that shows fluorescence if illuminated by light.
The blue dye has a light absorption band in the wavelength range of 350nm to 420nm, preferably showing a light absorption maximum.
If desired, the blue dye may be characterized by any one or a combination of more of the following technical features:
a) solubility: at least 0.1g in 100g of TEGMA at 23 ℃;
b) has a light absorption band in the wavelength range of 350nm to 420 nm;
c) a fluorescent band having a range of 440nm to 550 nm;
d) does not have a light absorption band in the wavelength range of 440nm to 500 nm;
e) comprising a terephthalic acid moiety.
The technical features a) and b), or a combination of a), b) and c) may sometimes be preferred.
Blue dyes typically have a light absorption band in the wavelength range of 300nm to 450nm, i.e. in the range associated with the UV region.
Such absorption may be advantageous because it substantially corresponds to or overlaps with the emission band of light of the apparatus used for the additive manufacturing technique.
Typically, blue dyes show a light absorption band in the same region of the electromagnetic spectrum, where the photoinitiator also shows light absorption.
Blue dyes are generally soluble in organic solvents and may also be soluble in radiation curable compositions.
According to one embodiment, the blue dye comprises a terephthalic acid moiety and thus may be characterized as a terephthalic acid dye.
Suitable examples of blue dyes include LumiluxTMBlue (Honeywell) and TinuvinTM326 (Ciba corporation).
The blue dye is typically present in the following amounts:
-a lower limit: at least 0.01 wt%, or at least 0.04 wt%, or at least 0.08 wt%;
-an upper limit: at most 0.1 wt%, or at most 0.5 wt%, or at most 1 wt%;
-a range: 0.01 wt% to 1 wt%, or 0.04 wt% to 0.5 wt%, or 0.08 wt% to 0.1 wt%;
wt% is relative to the weight of the curable composition.
The radiation curable compositions described herein may also comprise stabilizers as component E.
The stabilizer may extend the shelf life of the curable composition, help prevent undesirable side reactions, and regulate the polymerization process of the radiation curable components present in the curable composition.
The addition of one or more stabilizers to the curable composition may further help to improve the precision or detail resolution of the surface of the 3-dimensional article to be produced.
In particular, it has been found that the addition of a stabilizer to the curable composition described herein can help to enhance the resolution and accuracy of the SLA process by reducing or avoiding undesirable scattering effects, as well as increase the shelf life of the curable composition.
Stabilizers that can be used generally comprise a phenol moiety.
Specific examples of the stabilizer that can be used include: p-Methoxyphenol (MOP), hydroquinone Monomethyl Ether (MEHQ), 2, 6-di-tert-butyl-4-methylphenol (BHT; Ionol), phenothiazine, 2,6, 6-tetramethylpiperidin-1-oxyl radical (TEMPO) and mixtures thereof.
If present, the stabilizer may be present in the following amounts:
-a lower limit: at least 0.001 wt%, or at least 0.005 wt%, or at least about 0.01 wt%;
-an upper limit: at most 0.02 wt%, or at most 0.05 wt%, or at most 0.5 wt%, at most 1 wt%,
-a range: 0.001 wt% to 1 wt%, or 0.005 wt% to 0.05 wt%;
wt% is relative to the weight of the curable composition.
According to one embodiment, the radiation curable composition I comprises:
component a1 ((meth) acrylate): 50 to 95 wt%, or 55 to 90 wt%;
component a2 (urethane (meth) acrylate): 0 wt% to 40 wt%, or 1 wt% to 40 wt%;
component B (photoinitiator): 0.01 wt% to 5 wt%, or 0.01 wt% to 3 wt%;
component C (red, orange or yellow dye): 0.001 wt% to 1 wt%, or 0.003 wt% to 0.5 wt%;
component D (blue dye): 0.01 wt% to 1 wt%, or 0.04 wt% to 0.5 wt%;
component E (stabilizer): 0.001 wt% to 1 wt%, or 0.005 wt% to 0.05 wt%;
the weight% is relative to the total composition.
The compositions described herein may be prepared by mixing the respective components, especially under stored light conditions. If desired, a speed mixer may be used.
Typically, component a1 is first provided. Other components were added as needed.
During storage, the compositions described herein are typically packaged in a suitable packaging device.
The curable compositions described herein are typically stored in a container. Suitable containers include receptacles, foil bags, filter cartridges, and the like.
The volume of the corresponding container is not particularly limited, but is usually in the range of 10ml to 200,000ml or 500ml to 10,000 ml.
The curable composition I described herein may also be provided as a kit comprising the curable composition I and instructions for use.
The instructions generally describe under what conditions the curable composition should be used.
The radiation curable composition I described herein can be used to produce transparent 3-dimensional articles.
The transparent 3-dimensional article obtained by curing the radiation curable composition I may be generally characterized by a combination of any one or more of the following technical features:
a) tensile strength: from 0.5MPa to 50MPa, or 1.0MPa to 30MPa according to ISO/DIN 53504 (2015-8);
b) elongation at break: from 10% to 1000%, or 50% to 500% according to ISO/DIN 53504 (2015-8);
c) shore A hardness: from 30 to 90 according to ISO/DIN 53505 (2000-8);
d) light transmittance: at least 50% for an optical length of 1mm when light having a wavelength in the range of 450nm to 600nm is used;
e) water contact angle: less than or equal to 100 degrees;
f) no tack to the surface of the cured (meth) acrylate;
g) color: red, orange or yellow is seen by the human eye.
The transparent 3-dimensional article is rubber elastic and has a red color.
The combination of the features b) and d), or b), d) and e), or b), d), e) and f) may sometimes be preferred.
The water contact angle as described below may be beneficial, especially if the 3-dimensional article is used as a mould in a wet (moist orhumid) environment.
According to one embodiment, the transparent 3-dimensional article has the shape of an orthodontic or dental article.
According to one embodiment, the transparent 3-dimensional article is a dental article and has the shape of a dental impression.
The radiation curable composition I described herein is especially useful for producing transparent elastomeric 3-dimensional articles by processing the radiation curable composition I in an additive manufacturing process comprising a radiation curing step, especially an SLA process.
A transparent elastic 3-dimensional article is thus obtained.
Such methods typically include the steps of:
providing a layer of a radiation curable composition on the surface,
radiation curing of those parts of the layer of radiation curable composition belonging to the 3-dimensional article to be produced,
providing an additional layer of the radiation curable composition in contact with the radiation cured surface of the aforementioned layer,
repeat the previous steps until a 3-dimensional product is obtained.
Such methods include the step of applying radiation to the surface of the radiation-curable material, wherein the radiation is applied only to those portions of the surface that will subsequently form part of the article to be produced.
The radiation may be applied by using, for example, a laser beam or by mask image projection. The use of a stereolithography method based on mask image projection (MIP-SL) is sometimes preferred because it allows for faster fabrication of the article.
The MIP-SL method can be described as follows:
i. a three-dimensional digital model of the article to be produced is provided.
Slicing the three-dimensional digital model through a set of horizontal planes.
Converting each lamella to a two-dimensional mask image.
Then, projecting the mask image onto a surface of a radiation curable material positioned on a building platform (e.g., having the shape of a vat) with the aid of a radiation source.
v. the radiation curable material is cured only in those areas that are exposed.
Moving the building platform containing the radiation curable material or layer of cured material relative to the radiation source, wherein a new layer of radiation curable material is provided in contact with the layer of cured material produced in the above step.
Repeating steps (iv) through (vi) until the desired article is formed.
The mask image may be projected onto the radiation curable material from top to bottom or from bottom to top relative to the orientation of the vat.
Using a bottom-up technique may be beneficial because less radiation curable material is needed.
It has been found that the radiation curable compositions described herein are particularly useful for processing them in a mask image projection stereolithography process using a bottom-up projection technique.
The transparent 3-dimensional article has a specific shape and can be used as a mold, support or cover for a radiation curable composition II, which is different from the radiation curable composition I used to produce the transparent 3-dimensional article.
The radiation curable composition II is cured by radiation which is irradiated through the transparent 3-dimensional article produced from the radiation curable composition I.
Specifically, the method can be described as follows:
the method comprises the following steps
a) Providing a radiation curable composition I as described herein,
b) curing the radiation curable composition I using radiation processing in an additive manufacturing process to obtain a transparent 3-dimensional article having an outer side and an inner side,
c) a radiation curable composition II is placed on the inside of the transparent 3-dimensional article,
d) photocuring the radiation curable composition II by irradiating light from the outside of the transparent 3-dimensional article,
e) optionally removing the transparent 3-dimensional article from the photocurable composition II.
The radiation curing step b) and the photocuring step d) are generally carried out at different wavelengths.
The radiation curing step b) is generally carried out in the wavelength range from 350nm to 420 nm.
The photocuring step d) is generally carried out in the wavelength range from 430nm to 500 nm.
The radiation curable composition II is different from the radiation curable composition I used for producing the transparent 3-dimensional article.
The radiation curable composition II is typically different from the radiation curable composition I in any one or a combination of more of the following technical features:
the amount and nature of the (meth) acrylate component;
-a filler content;
-opacity;
-viscosity.
The radiation curable composition II generally comprises
-a radiation curable component, in particular a radiation curable component comprising a (meth) acrylate moiety,
-a photoinitiator, in particular a photoinitiator comprising an α -diketone moiety,
-optionally a filler.
Examples of photoinitiators comprising α -dione moieties include moieties selected from benzophenone, xanthone or quinone.
Examples include camphorquinone, benzil, furylcyclohexanedione, 3,6, 6-tetramethylcyclohexanedione, phenylanthraquinone and 1-phenyl-1, 2-propanedione.
Such photoinitiators are typically used in combination with aliphatic amines.
According to one embodiment, the radiation curable composition B is selected from a dental cement, a dental adhesive or a dental (flowable) composite.
Examples of suitable dental cements are described in US 8,236,871B 2(Hecht et al).
The invention also relates to a method for producing a transparent positioning tray, comprising the following steps:
providing a radiation curable composition I as described herein,
-providing a personalized data set relating to at least a part of the dental condition of the patient,
using the personalized data set for processing the radiation curable composition I in an additive manufacturing process comprising a radiation step to obtain a 3-dimensional article having the shape of a transparent positioned tray having an outer surface and an inner surface, the inner surface corresponding to the surface of the dental condition,
the method may further include the step of placing the orthodontic bracket in contact with the inner surface of the 3-dimensional article. Orthodontic brackets typically include a layer of a radiation curable composition.
The invention also relates to a method of securing orthodontic brackets to tooth surfaces in a patient's mouth.
Such methods may further include the step of placing a transparent positioning tray containing orthodontic brackets in the patient's mouth.
The method may further include the step of directing light from an outer surface of the transparent positioning tray to the orthodontic bracket including the layer of radiation curable composition.
This method step generally causes curing of the radiation curable composition positioned on the orthodontic bracket and thereby secures the orthodontic bracket to the tooth surface pertaining to the tooth condition.
The method may further include the step of removing the transparent positioning tray from the patient's mouth.
The invention also relates to a kit comprising:
the radiation curable composition I described herein, which is radiation curable by application of radiation having a wavelength in the range of from 350nm to 420nm, and
-a radiation curable composition II, which is different from the radiation curable composition I and is radiation curable by applying radiation having a wavelength in the range of 420nm to 500 nm.
Such kits are particularly useful for producing 3-dimensional cured articles based on radiation curable compositions II by means of radiation curable compositions I from which transparent molds or transparent covers have been produced by additive manufacturing processes.
According to one embodiment, the cartridge comprises
-a radiation curable composition I as described herein, typically contained in a packaging unit, and
orthodontic brackets comprising a layer of radiation curable dental adhesive or cement.
All components used in the dental composition of the present invention should be sufficiently biocompatible, i.e. the composition does not produce toxic, injurious or immunological reactions in living tissue.
The radiation curable compositions I described herein typically do not comprise any one or a combination of more of the following components:
-a cationically curable component in an amount of more than 5% by weight;
-an inorganic pigment in an amount of more than 1 wt% or more than 0.1 wt%;
-filler particles having a refractive index which differs from the matrix by more than 0.5 in an amount of more than 5% by weight;
the weight% is relative to the total composition.
Thus, the curable compositions described herein are substantially free of any or all of the above components.
The entire disclosures of the patents, patent documents, and publications cited herein are incorporated by reference in their entirety as if each were individually incorporated. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. The above specification, examples and data provide a description of the manufacture and use of the composition of the invention and of the method of the invention. The present invention is not limited to the embodiments disclosed herein. Those skilled in the art will appreciate that many alternative embodiments of the invention can be made without departing from the spirit and scope of the invention.
The following examples are intended to further illustrate the invention.
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