WO2024067506A1 - Method for post-treating an object - Google Patents

Method for post-treating an object Download PDF

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Publication number
WO2024067506A1
WO2024067506A1 PCT/CN2023/121175 CN2023121175W WO2024067506A1 WO 2024067506 A1 WO2024067506 A1 WO 2024067506A1 CN 2023121175 W CN2023121175 W CN 2023121175W WO 2024067506 A1 WO2024067506 A1 WO 2024067506A1
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WO
WIPO (PCT)
Prior art keywords
silicone composition
curable silicone
organopolysiloxane
organopolysiloxane resin
total weight
Prior art date
Application number
PCT/CN2023/121175
Other languages
French (fr)
Inventor
Liya JIA
Yuanzhi YUE
Genli WU
Original Assignee
Elkem Silicones Shanghai Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Elkem Silicones Shanghai Co., Ltd. filed Critical Elkem Silicones Shanghai Co., Ltd.
Publication of WO2024067506A1 publication Critical patent/WO2024067506A1/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
    • C09D183/04—Polysiloxanes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04—Coating
    • C08J7/0427—Coating with only one layer of a composition containing a polymer binder
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04—Coating
    • C08J7/046—Forming abrasion-resistant coatings; Forming surface-hardening coatings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/12—Chemical modification
    • C08J7/16—Chemical modification with polymerisable compounds
    • C08J7/18—Chemical modification with polymerisable compounds using wave energy or particle radiation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2300/00—Characterised by the use of unspecified polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2483/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
    • C08J2483/04—Polysiloxanes

Definitions

  • the invention relates to a method for post-treating an object, preferably a 3D printed object with a curable silicone composition, a post-treatment agent and a 3D printing process comprising such a method.
  • additive manufacturing (AM) technique also referred to 3D printing technology has developed rapidly, which makes it possible to manufacturing objects more efficiently compared to conventional methods due to layer-by-layer deposition.
  • AM additive manufacturing
  • Such technique possesses varies advantages, for example reduced production cycle, enhanced material utilization, customized production of complex, special-shaped objects and so on.
  • materials can be printed via 3D printing technology such as metal, polymers or ceramic.
  • silicone materials may be used by means of extrusion 3D printing technology and UV curable printing technology.
  • US20220080684A1 disclose a method for cleaning and post-processing 3D printed silicones, comprising a) providing a 3D printed part; b) immersing the part into a first liquid medium that is incompatible with the material from which the part is made from, and c) exposing the part to ultrasound.
  • the solvent used not only removes excess resin, but also ensures dimensional stability as well as oxygen elimination, thereby facilitating surface curing of the part.
  • this reference is not intended to improve the surface condition of the 3D printed objects.
  • US10625292B2 discloses a system for treating uneven surfaces of additive manufactured objects which may improve the transparency and glossiness of the surfaces.
  • the system operates a sprayer to apply fluid material to the uneven surface so as to smooth the surface, or otherwise the system operates an actuator to dip the additive manufactured object into a bath of such a fluid material. No information on the chemical composition of useful fluid material is given.
  • WO2019127453A1 discloses a method for remedying the ladder-like appearance on the surface of 3D printed objects, comprising the steps of S1) coating a surface of the substrate with an uncured resin liquid; S2) applying a uniform pressure to the surface of the substrate through the transparent film, the pressure causes the uncured resin liquid to fill the surface gap of the substrate, and flat the surface of the entire uncured resin liquid; S3) curing the uncured resin liquid by UV while maintaining the pressure, to obtain a smooth resin surface; S4) the entire substrate is subjected to heat annealing to eliminate the internal stress of the substrate to achieve uniform performance for the substrate.
  • problem of surface roughness might be resolved here, it is realized by means of special processing step (uniform pressure) , rather than the selection of post-treatment.
  • the object of the invention is to provide a method for post-treating a surface of an object, preferably a 3D printed object. After the post-treatment, thus obtained post-treated object is much slippery in hand feeling. Moreover, more resistant to scratch and/or wear of the post-treated object are achieved by present method. In addition, matte or glossy surface is exhibited which is useful for varied applications.
  • an object preferably a 3D printed object having significant improved surface condition and anti-wear and/or anti-scratch property
  • inventive curable composition comprising at least one organopolysiloxane E to the surface of the object followed by curing, wherein organopolysiloxane E comprises at least one siloxy unit T of formula LSiO 3/2 and/or at least one siloxy unit Q of formula SiO 4/2 with L denotes OH or organic group.
  • L may denote OH, C 1-20 alkoxy, C 1-20 alkyl, C 2-20 alkenyl, C 6-20 aryl, each of the C 1- 20 alkoxy, C 1-20 alkyl, C 2-20 alkenyl and C 6-20 aryl is optionally substituted with at least one group selected from OH, C 1-6 alkyl, C 6 -C 10 aryl, epoxy group, and acrylate group.
  • L may denote OH, C 1-12 alkoxy, C 1-12 alkyl, C 2-12 alkenyl, C 6 - 10 aryl, the C 1-12 alkyl is optionally substituted with at least one group selected from epoxy group, and acrylate group.
  • L may denote OH, methoxy, ethoxy, methyl, ethyl, vinyl, epoxy group substituted C 1-6 alkyl, or acrylate group substituted C 1-6 alkyl.
  • L may denote methyl or vinyl.
  • L in each siloxy unit T may be identical to or different from each other when more than more siloxy unit T are present.
  • the present disclosure relates to a method for post-treating a surface of an object, preferably a 3D printed object, comprising the steps of
  • the curable silicone composition comprises at least one organopolysiloxane E comprising at least one siloxy unit T of formula LSiO 3/2 and/or at least one siloxy unit Q of formula SiO 4/2 with L defined as above.
  • the object to be post-treated may be any object.
  • the object to be post-treated may be made of silicone, plastic, metal or ceramic and the like, depending on applications.
  • One example of such object may be a medical device, preferably an additive manufactured medical device.
  • the medical device may be selected from catheters, implantable biosensors, or prosthesis.
  • the medical device may be prosthesis such as hip prosthesis, knee prosthesis, or breast prosthesis etc.
  • Another example of such object may be fabric, especially silicone-made fabric, from which a variety of wearable consumer products including clothes, shoes, hats, bags and luggage, or ornaments and so on could be produced.
  • the post-treated fabric with inventive curable composition may exhibit good hand feeling (tactility) , either matte or glossy surface together with proper mechanical property to meet various needs in consumer products.
  • object to be post-treated may be skin-like material, especially those made of silicone, which could be used to manufacture human-mimic products for example robots, dolls, or mannequins for window display to mimic human skin.
  • slippery hand-feeling and matte or glossy surface are essential and desirable which could be realized by post-treatment with inventive curable composition.
  • the object after post-treatment has exhibited much slippery in hand feeling, increased wear and scratch resistance, matte or glossy surface with surface texture resulted from layer-by-layer deposition invisible.
  • the component organopolysiloxane E is essential for the inventive method.
  • the intended effect of present invention as mentioned above would not be achieved, in absence of the essential component.
  • the present disclosure relates to a curable silicone composition used in the first aspect of present disclosure.
  • the present disclosure relates to use of the curable silicone composition as mentioned in the first or second aspect of present disclosure for imparting at least one of glossy or matte surface, improved hand feeling, improved anti-wear and anti-scratch properties to an object, preferably a 3D printed object, more preferably a 3D printed silicone object.
  • the present disclosure relates to a post-treatment agent comprising or basically consisting of the curable silicone composition as mentioned in the first or second aspect of present disclosure.
  • the present disclosure relates to a 3D printing process comprising the following steps:
  • the object has a surface made of polymeric material, preferably the object is made of polymeric material, more preferably made of silicone material,
  • the present disclosure refers to medical devices, wearable consumer products, or human-mimic products having skin-like appearance, with the surface of which treated by the method according to the first aspect of the present disclosure.
  • the medical device may be an additive manufactured medical device.
  • the medical device may be selected from catheters, implantable biosensors, or prosthesis.
  • the medical device may be prosthesis such as hip prosthesis, knee prosthesis, or breast prosthesis etc.
  • the wearable consumer products may be selected from clothes, shoes, hats, bags and luggage, or ornaments.
  • the wearable consumer products are made from additive manufacture process.
  • the human-mimic products may be selected from robots, dolls, or mannequins for window display.
  • the human-mimic products are made from additive manufacture process.
  • the present disclosure refers to an article made of silicone, plastic, metal or ceramic, comprising a surface treated by the method according to the first aspect of present disclosure.
  • the article may be an additive manufactured article.
  • Figure 1 depicts the structure of a 3D printed ring in accordance with present invention.
  • Figure 2 depicts the comparison of 3D printed object with inventive post treatment according to Example 1-1 vs. the 3D printed object without the inventive post treatment
  • the viscosities under consideration in the present specification correspond to a dynamic viscosity magnitude that is measured, in a manner known per se, at about 23°C, with a machine of e.g., Brookfield type, in accordance with ASTM D445.
  • the viscosity under consideration in the present specification is the dynamic viscosity at about 23°C, known as the “Newtonian” viscosity, i.e., the dynamic viscosity that is measured, in a manner known per se, at a sufficiently low shear rate gradient so that the viscosity measured is independent of the rate gradient.
  • compositions claimed herein through use of the term “comprising” may include any additional additive, adjuvant, or compound, unless stated to the contrary.
  • hydrocarbon group refers to a linear, branched chain or cyclic hydrocarbon radical or any combination thereof.
  • hydrocarbon group includes, but is not limited to, aliphatic hydrocarbyl and aromatic hydrocarbyl.
  • 3D printing is generally associated with a host of related technologies used to fabricate physical object from computer generated, e.g., computer-aided design (CAD) , data sources.
  • CAD computer-aided design
  • This disclosure generally incorporates ASTM Designation F2792-12a, "Standard Terminology for Additive Manufacturing Technologies Under this ASTM standard.
  • 3D printer is defined as “a machine used for 3D printing” and “3D printing” is defined as “the fabrication of objects through the deposition of a material using a print head, nozzle, or another printer technology. "
  • additive manufacturing is defined as "a process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies. Synonyms associated with and encompassed by 3D printing include additive fabrication, additive processes, additive techniques, additive layer manufacturing, layer manufacturing, and freeform fabrication. " Additive manufacturing (AM) may also be referred to as rapid prototyping (RP) . As used herein, “3D printing” is generally interchangeable with “additive manufacturing” and vice versa.
  • Print is defined as depositing of a material, here a silicone composition, using a print head, nozzle, or another printer technology.
  • 3D or three-dimensional printed article, object or part means an article, object or part obtained by additive manufacturing or 3D printing as disclosed above.
  • all 3D printing processes have a common starting point, which is a computer-generated data source or program which may describe an object.
  • the computer-generated data source or program can be based on an actual or virtual object. For example, an actual object can be scanned using a 3D scanner and scan data can be used to make the computer-generated data source or program. Alternatively, the computer-generated data source or program may be designed from Scratch.
  • the computer-generated data source or program is typically converted into a standard tessellation language (STL) file format; however other file formats can also or additionally be used.
  • the file is generally read into 3D printing software, which takes the file and optionally user input to separate it into hundreds, thousands, or even millions of "slices. "
  • the 3D printing software typically outputs machine instructions, which may be in the form of G-code, which is read by the 3D printer to build each slice.
  • the machine instructions are transferred to the 3D printer, which then builds the object, layer by layer, based on this slice information in the form of machine instructions. Thicknesses of these slices may vary.
  • An extrusion 3D printer is a 3D printer where the material is extruded through a nozzle, syringe or orifice during the additive manufacturing process.
  • Material extrusion generally works by extruding material through a nozzle, syringe or orifice to print one cross-section of an object, which may be repeated for each subsequent layer. The extruded material bonds to the layer below it during cure of the material.
  • the method for additive manufacturing a three-dimensional elastomer article uses an extrusion 3D printer.
  • the additive manufacturing material like silicone compositions are extruded through a nozzle.
  • the nozzle may be heated to aid in dispensing the silicone composition.
  • the average diameter of the nozzle defines the thickness of the layer.
  • the diameter of the layer is comprised from 5 to 5000 ⁇ m, preferably from 10 to 2000 ⁇ m and most preferably from 50 to 1000 ⁇ m.
  • the distance between the nozzle and the substrate is an important parameter to assure good shape. Preferably it is comprised from 60 to 150 %, more preferably from 80 to 120 %of the nozzle average diameter.
  • the silicone composition to be dispensed through the nozzle may be supplied from a cartridge-like system.
  • the cartridge may include a nozzle or nozzles with an associated fluid reservoir or fluids reservoirs. It is also possible to use a coaxial two cartridges system with a static mixer and only one nozzle. Pressure will be adapted to the fluid to be dispensed, the associated nozzle average diameter and the printing speed.
  • the viscosity of the silicone compositions is greatly lowered and so permits the printing of fine layers.
  • Cartridge pressure could vary from 1 to 20 bars, preferably from 2 to 10 bar and most preferably from 2.5 to 8 bar.
  • An adapted equipment using aluminum cartridges shall be used to resist such a pressure.
  • the nozzle and/or build platform moves in the X-Y (horizontal plane) to complete the cross section of the object, before moving in the Z axis (vertical) plane once one layer is complete.
  • the nozzle has a high X-Y-Z movement precision such as 10 ⁇ 300 ⁇ m. After each layer is printed in the X, Y work plane, the nozzle is displaced in the Z direction only far enough that the next layer can be applied in the X, Y work plane. In this way, the object which becomes the 3D article is built one layer at a time from the bottom upwards.
  • the distance between the nozzle and the previous layer is an important parameter to assure good shape.
  • it should be comprised from 60 to 150 %, preferably from 80 to 120 %of the nozzle average diameter.
  • printing speed is comprised between 0.1 and 100 mm/s, preferably between 1 and 50 mm/s to obtain the best compromise between good accuracy and manufacture speed.
  • “Material jetting” is defined as “an additive manufacturing process in which droplets of build material are selectively deposited. " The material is applied with the aid of a printing head in the form of individual droplets, discontinuously, at the desired location of the work plane (Jetting) .
  • the application of the materials by means of inkjet printing imposes specific requirements on the viscosity of the materials.
  • one or a plurality of reservoirs are subject to pressure and being connected via a metering line to a metering nozzle. Upstream or downstream of the reservoir there may be devices which make it possible for multicomponent addition-crosslinking silicone compositions to be homogeneously mixed and/or to evacuate dissolved gases.
  • One or a plurality of jetting apparatuses operating independently of one another may be present, to construct the elastomer article from different addition-crosslinking silicone compositions, or, in the case of more complex structures, to permit composite objects made from silicone elastomers and other plastics.
  • the individual metering nozzles can be positioned accurately in x-, y-, and z-directions to permit precisely targeted deposition of the silicone composition drops on the substrate or, in the subsequent course of formation of shaped objects, on the silicone rubber composition which has already been placed and which optionally has already been crosslinked.
  • the 3D printer utilizes a dispenser, e.g., a nozzle or print head, for printing the particular curable silicone composition.
  • a dispenser e.g., a nozzle or print head
  • the dispenser may be heated before, during, and after dispensing the silicone composition.
  • More than one dispenser may be utilized with each dispenser having independently selected properties.
  • this method can use support material to build the object. If the object is printed using support material or rafts, after the printing process is complete, they are typically removed leaving behind the finished object.
  • the 3D printing process may comprise extruding or jet printing.
  • the 3D printing process may comprise UV curing process such as UV-Stereolithography (SLA) , UV-Digital Light processing (DLP) , Continuous Liquid Interface Production (CLIP) , UV-extrusion and Inkjet Deposition.
  • SLA UV-Stereolithography
  • DLP UV-Digital Light processing
  • CLIP Continuous Liquid Interface Production
  • UV-extrusion and Inkjet Deposition UV curing process
  • the useful building material for an object may contain polymer material, ceramic, metal material, and preferably based on or basically consisting of the polymer material (such as silicone or plastic) , especially curable silicone composition.
  • the silicone compositions available are well known and in principle may be any curable silicone composition that has the siloxy units-based backbone and can be used for producing a silicone elastomer article, such as the liquid silicone rubber (LSR) which has been already used widely.
  • LSR liquid silicone rubber
  • an additive manufactured object which thus may be composed of several parts based on different materials, at least part of its exterior surface is preferably made of polymeric material, in particular the silicone rubber.
  • the suitable silicone composition used as building material may be curable chemically via condensation or addition crosslinking reactions.
  • a curable silicone composition usually comprises:
  • - L S is a reactive group like hydroxyl, alkoxy, alkenyl, and alkynyl groups,
  • N S may be the same or different and each represent a monovalent non-reactive hydrocarbon radical having for example from 1 to 30 carbon atoms, preferably selected from alkyl and aryl groups,
  • - a is an integer of 1, 2 or 3
  • b is an integer of 0, 1 or 2 and the sum of a + b is 1, 2 or 3
  • - c is an integer of 0, 1, 2 or 3
  • - N S1 may be identical or different and represent a monovalent non-reactive hydrocarbon radical having for example from 1 to 30 carbon atoms, preferably selected from alkyl and aryl groups,
  • component (B) a cross-linking organosilicon compound having at least 2 silicon-bonded reactive groups;
  • a coating of curable silicone composition may be applied to at least part of the exterior surface or fabricated edges of an object, preferably a 3D printed object, followed by curing at room temperature or under heat or UV radiation.
  • applying or “applied” used herein is well known to the skilled person and refers to all application forms or ways which allows the curable silicone composition to cover sufficiently the exterior surface or fabricated edges of an object, preferably a 3D printed object to be post-treated.
  • the applying includes dip coating for example dipping into a treatment bath of the curable silicone composition, spraying coating, curtain coating or spinning coating or any other manners, preferably dip coating.
  • the curable silicone composition used for post treatment may comprises
  • (C) at least one catalyst C capable of catalyzing or promoting the hydrosilylation reaction between component (A) and component (B) ;
  • L denotes OH or organic group.
  • L may denote OH, C 1-20 alkoxy, C 1-20 alkyl, C 2-20 alkenyl, C 6-20 aryl, each of the C 1- 20 alkoxy, C 1-20 alkyl, C 2-20 alkenyl and C 6-20 aryl is optionally substituted with at least one group selected from OH, C 1-6 alkyl, C 6 -C 10 aryl, epoxy group, and acrylate group.
  • L may denote OH, C 1-12 alkoxy, C 1-12 alkyl, C 2-12 alkenyl, C 6 -C 10 aryl, the C 1-12 alkyl is optionally substituted with at least one group selected from epoxy group, and acrylate group.
  • L may denote OH, methoxy, ethoxy, methyl, ethyl, vinyl, epoxy group substituted C 1-6 alkyl, or acrylate group substituted C 1-6 alkyl.
  • L may denote methyl or vinyl.
  • L in each siloxy unit T may be identical to or different from each other when more than one siloxy unit T are present.
  • the organopolysiloxane compound A is at least one organopolysiloxane polymer having at least two alkenyl radicals bonded to silicon atoms.
  • the alkenyl radicals may be at any position on the chain (e.g. main chain) of organopolysiloxane, for example, at the ends or in the middle of the main chain, or both at the ends and in the middle of the main chain.
  • the aliphatic alkenyl groups like vinyl or allyl, or the arylalkenyl groups such as styryl can be regarded as an alkenyl radical.
  • the alkenyl radical is able to react with the hydrogen bonded to Si-atom under an addition reaction like hydrosilylation.
  • the organopolysiloxane compound A comprises:
  • - L 1 represents a monovalent radical containing from 2 to 12 carbon atoms, having at least one alkenyl radical
  • N may be the same or different and each represents a monovalent radical containing from 1 to 20 carbon atoms and does not comprise an alkenyl radical
  • - C’ is an integer of 0, 1, 2 or 3.
  • the organopolysiloxane compound (A) may substantially or entirely consist of the siloxy units of formulae (I-1) and (I-2) .
  • the organopolysiloxane compound may be of a linear, branched or cyclic structure.
  • the skilled persons understand that in case of linear or branched structure the organopolysiloxane polymer may be terminated by group –R T or –SiR T 3 wherein R T , independently from each other, denotes a hydrocarbonyl group such as alkyl, alkoxy, alkenyl or aryl.
  • the monovalent radical includes preferably hydrocarbonyl group or radical consisting of C, H and O atoms, such as alkyl, alkoxy, (meth) acrylic, alkenyl or aryl groups, that may be linear, branched or cyclic and may be substituted by one or more substituents like halogen atoms.
  • hydrocarbonyl group or radical consisting of C, H and O atoms, such as alkyl, alkoxy, (meth) acrylic, alkenyl or aryl groups, that may be linear, branched or cyclic and may be substituted by one or more substituents like halogen atoms.
  • alkyl and alkoxy groups may advantageously have 1 to 18, more preferably 1 to 12, most preferably 1 to 8 carbon atoms and may be unsubstituted or substituted by halogens like fluorine.
  • alkyl and alkoxy groups include methyl, ethyl, propyl, 3, 3, 3-trifluoropropyl, methoxy and ethoxy groups.
  • Alkenyl groups may preferably have 2 to 12, more preferably 2 to 8 carbon atoms and thus include for example vinyl, propenyl and allyl groups.
  • Aryl groups may have preferably 6 to 20, more preferably 6 to 12 carbon atoms and may be unsubstituted or substituted by halogens like fluorine.
  • examples of aryl group include phenyl, tolyl, xylyl or naphthyl group.
  • Group L 1 is preferably selected from alkenyl groups, such as vinyl or allyl.
  • Group N is preferably selected from alkyl, alkoxy and aryl groups.
  • Z is selected from C 1 -C 8 alkyl group, and/or C 6 -C 20 aryl groups.
  • Examples of the units of formula (I-1) may include, but not limited to, vinyl dimethylsiloxy, vinylphenylmethylsiloxy, vinyl methylsiloxy and vinyl siloxy units.
  • the examples of the unit of formula (I-2) may include, but not limited to, SiO 4/2 unit, dimethyl siloxy, methyl phenyl siloxy, diphenyl siloxy, methyl siloxy and phenyl siloxy group.
  • organopolysiloxane compound (A) may include, but not limited to, linear or cyclic compounds such as dimethylpolysiloxane (including dimethylvinylsilyl end group) , (methylvinyl) (dimethyl) polysiloxane copolymers (including trimethylsilyl end group) , (methylvinyl) (dimethyl) polysiloxane copolymers (including dimethylvinylsilyl end group) and cyclic methyl vinyl polysiloxane.
  • linear or cyclic compounds such as dimethylpolysiloxane (including dimethylvinylsilyl end group) , (methylvinyl) (dimethyl) polysiloxane copolymers (including trimethylsilyl end group) , (methylvinyl) (dimethyl) polysiloxane copolymers (including dimethylvinylsilyl end group) and cyclic methyl vinyl polysiloxane.
  • the organopolysiloxane compound A may have a alkenyl content (such as vinyl content) of 0.0001 ⁇ 40wt. %, preferably 0.001 ⁇ 35wt%, more preferably 0.01 ⁇ 30wt%, based on the total weight of organopolysiloxane compound A.
  • alkenyl content such as vinyl content
  • the organohydrogenopolysiloxane compound B is an organopolysiloxane containing at least two hydrogen atoms per molecule, bonded to an identical or different silicon atom, so as to perform hydrosilylation reaction with organopolysiloxane compound A.
  • the SiH group in organohydrogenopolysiloxane compound B can be at any position of the chain (such as main chain) of organohydrogenopolysiloxane, for example, at ends or in the middle of the molecular chain, or both at ends and in the middle of the molecular chain.
  • the organohydrogenopolysiloxane compound B is an organopolysiloxane comprising:
  • - d’ is an integer of 1 or 2 or 3
  • e’ is an integer of 0, 1 or 2
  • the sum of (d+e) is an integer of 1, 2 or 3;
  • - L 2 represents identically or differently a monovalent linear, branched or cyclic alkyl group containing from 1 to 30 carbon atoms, preferably selected from C1-8 alkyl groups including alkyl groups optionally substituted with at least one halogen atom, and from aryl groups, especially C6-20 aryl groups, and chosen from the group formed by methyl, ethyl, propyl, 3, 3, 3-trifluoropropyl, and
  • - f’ is an integer of 0, 1, 2 or 3.
  • L 2 can be selected from methyl, ethyl, propyl, 3, 3, 3-trifluoropropyl, phenyl, xylyl and tolyl.
  • the organohydrogenopolysiloxane compound B may be formed solely from siloxy units of formula (II-1) or may also comprise units of formula (II-2) . It may have a linear, branched or cyclic structure.
  • siloxy units of formula (II-1) are especially the following units: H (CH 3 ) 2 SiO 1/2 , and HCH 3 SiO 2/2 .
  • These linear organopolysiloxanes may be oils with a dynamic viscosity from about 1 to 1000000 mPa. s at 25°C, generally from about 1 to 50000 mPa. s at 25°C or preferably from about 5 to 10000 or 5000 mPa. s at 25°C.
  • organohydrogenopolysiloxane compound B examples include, but not limited to, linear or cyclic compounds, for example, dimethyl polysiloxane having hydrogenated dimethyl siloxy end group, copolymer having (dimethyl) (hydrogenmethyl) polysiloxane units having trimethyl siloxy end group, copolymer having (dimethyl) (hydrogenmethyl) polysiloxane units having hydrogenated dimethyl siloxy end group, hydrogenated methyl polysiloxane having trimethylsiloxy end group, and cyclic hydrogenated methyl polysiloxane.
  • linear or cyclic compounds for example, dimethyl polysiloxane having hydrogenated dimethyl siloxy end group, copolymer having (dimethyl) (hydrogenmethyl) polysiloxane units having trimethyl siloxy end group, copolymer having (dimethyl) (hydrogenmethyl) polysiloxane units having hydrogenated dimethyl siloxy end group, hydrogenated methyl polysiloxane having
  • the organohydrogenopolysiloxane compound B may be a three-dimensional net-like organohydrogensiloxane resin containing at least two different units selected from the group comprising or consisting of
  • siloxy unit T or Q preferably Q
  • siloxy unit M, D and T comprises a hydrogen atom
  • the mole ratio of M unit to Q unit in the organohydrogensiloxane resin B is from 0.5 to 8 mol/mol, preferably from 0.5 to 6 mol/mol, more preferably from 0.8 to 5 mol/mol.
  • the mass content of SiH is between 0.001 wt%and 70 wt%, preferably between 0.5 wt%and 60 wt%and more preferably between 1.0 wt%and 50 wt%, based on the total weight of component B.
  • Catalyst C comprises at least one metal from the platinum group or the compound thereof.
  • the platinum metal catalyst is well known in organosilicon field and commercially available.
  • the platinum group metal can further comprise ruthenium, rhodium, palladium, osmium and iridium.
  • the catalyst can be composed of following components: a platinum group metal or compound thereof or a combination thereof. Examples of such a catalyst include but not limited to: platinum black, chloroplatinic acid, platinum dichloride, reaction product of chloroplatinic acid with monohydric alcohol.
  • compounds of platinum and rhodium are used.
  • the preferred catalyst is platinum.
  • the platinum catalyst ought preferably to be used in a catalytically sufficient amount, to allow sufficiently rapid crosslinking at room temperature.
  • 1 to 10000 ppm by weight of the catalyst are used, based on the amount of Pt atom, preferably 1 to 100 ppm by weight, more preferably 1 to 50 ppm by weight, relative to the total weight of the curable silicone composition.
  • the silicone composition may contain those catalysts suitable for UV curing, such as platinum-based photo-curing catalysts.
  • platinum-based photo-curing catalysts include: bis (acetylacetonate) platinum, trimethyl (acetylacetonate) platinum complex, trimethyl (2, 4-pentanedione) platinum complex, trimethyl (3, 5-heptanedione) platinum complex, trimethyl (methyl acetoacetate) platinum complex, bis (2, 4-pentanedione) platinum complex , bis (2, 4-hexanedione) platinum complex, bis (2, 4-heptanedione) platinum complex, bis (3, 5-heptanedione) platinum complex and bis (1-phenyl-1, 3-butanedione) platinum complex and the like.
  • the amount of the platinum-based photo-curing catalyst is 1-50000 ppm, preferably 5-1000 ppm, based on the total weight of the entire silicone composition, based on platinum metal.
  • an appropriate solvent can be added to dissolve it.
  • Suitable solvents include 2- (2-butoxyethoxy) ethyl acetate, diethylene glycol butyl ether acetate, various halogenated hydrocarbons and the like.
  • the amount of the solvent is preferably sufficient to dissolve the catalyst.
  • the organopolysiloxane E comprises at least one siloxy unit T of formula LSiO 3/2 and/or at least one siloxy unit Q of formula SiO 4/2 , wherein L denotes OH or organic group.
  • L may denote OH, C 1-20 alkoxy, C 1-20 alkyl, C 2-20 alkenyl, C 6-20 aryl, each of the C 1- 20 alkoxy, C 1-20 alkyl, C 2-20 alkenyl and C 6-20 aryl is optionally substituted with at least one group selected from OH, C 1-6 alkyl, C 6 -C 10 aryl, epoxy group, and acrylate group.
  • L may denote OH, C 1-12 alkoxy, C 1-12 alkyl, C 2-12 alkenyl, C 6-10 aryl, the C 1-12 alkyl is optionally substituted with at least one group selected from epoxy group, and acrylate group.
  • L may denote OH, methoxy, ethoxy, methyl, ethyl, vinyl, epoxy group substituted C 1-6 alkyl, or acrylate group substituted C 1-6 alkyl.
  • L may denote methyl or vinyl.
  • L in each siloxy unit T may be identical to or different from each other when more than one siloxy unit T are present.
  • the organopolysiloxane E may comprise or basically consisting of at least one organopolysiloxane resin comprising at least one organopolysiloxane resin E’ , at least one organopolysiloxane resin E”, or a combination thereof.
  • the organopolysiloxane resin may comprise or basically consisting of an organopolysiloxane resin E’ selected from:
  • L denotes OH or organic group.
  • L may denote OH, C 1-20 alkoxy, C 1-20 alkyl, C 6-20 aryl, each of the C 1-20 alkoxy, C 1- 20 alkyl and C 6-20 aryl is optionally substituted with at least one group selected from OH, C 1-6 alkyl, C 6 -C 10 aryl, epoxy group, and acrylate group.
  • L may denote OH, C 1-12 alkoxy, C 1-12 alkyl, C 6 - 10 aryl, the C 1-12 alkyl is optionally substituted with at least one group selected from epoxy group, and acrylate group.
  • L may denote OH, methoxy, ethoxy, methyl, ethyl, epoxy group substituted C 1-6 alkyl, or acrylate group substituted C 1-6 alkyl.
  • L may denote methyl
  • L may be identical to or different from each other, either in each siloxy unit as mentioned above or in more than one siloxy unit as mentioned above.
  • L’ represents alkenyl, preferably alkenyl with 2 to 12, more preferably 2 to 6 carbon atoms, in particular preferably vinyl or allyl, most preferably vinyl.
  • the organopolysiloxane resin E’ may be the organopolysiloxane resin of formula MD Vi Q, which is basically consisted of the following units:
  • the ratio of (the monovalent siloxy unit M+ the divalent siloxane unit D Vi ) to the tetravalent siloxy unit Q is from 0.8 to 1.6.
  • the ratio of (the monovalent siloxy unit M + the trivalent siloxy unit T Vi ) to the tetravalent siloxy unit Q is from 0.6 to 1.2, and the ratio of the trivalent siloxy unit T Vi to the tetravalent siloxy unit Q is from 0.6 to 1.
  • the organopolysiloxane resin E’ may be the organopolysiloxane resin of formula MM Vi Q, which is basically consisted of the following units:
  • the organopolysiloxane resin E’ has a weight-average molecular weight in range of 200-50,000 g/mol, preferably 500-30,000 g/mol, as measured by gel permeation chromatography and calculated using polystyrene as standard.
  • the organopolysiloxane resin may comprise or basically consisting of at least one organopolysiloxane resin E”, with the proviso that siloxy unit T of formula LSiO 3/2 are present within the formula with L defined as above.
  • the organopolysiloxane resin E may be spherical particles with a particle size D50 from 0.2 to 60 ⁇ m, preferably from 0.5 to 40 ⁇ m, more preferably from 0.8 to 30 ⁇ m.
  • Particle Size Distribution D50 is also known as the median diameter or the medium value of the particle size distribution, it is the value of the particle diameter at 50%in the cumulative distribution. It is one of important and well-known parameters characterizing particle size.
  • the size distribution and volume mean diameter for a particle size distribution may be calculated using a laser light scattering PSD system such as those commercially available from Malvern.
  • polysilsesquioxane is a preferred organopolysiloxane resin E”.
  • Polysilsesquioxanes are colorless solids that adopt cage-like or ladder-like structure.
  • the polysilsesquioxane may be MIRASIL MICROPEARL 40, and the like.
  • the organopolysiloxane E may be comprised in an amount of from 0.5wt%to 70wt%, preferably from 3wt%to 50wt%, more preferably from 10wt%to 40wt%, based on the total weight of the curable silicone composition.
  • the organopolysiloxane E may comprise or basically comprise the organopolysiloxane resin E’ in an amount of from 0wt%to 50wt% (not including 0wt%, ) for example from 0.1wt%to 50wt%, wherein lower limit may be 0.1wt%, 1wt%, 2wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, or 45wt%or any numerical value contained therebetween, and upper limit may be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%or any numerical value contained therebetween, based on the total weight of the curable silicone composition.
  • the organopolysiloxane E may comprise or basically comprise organopolysiloxane resin E’ in an amount of from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition, so that the obtained post-treated product could present glossy surface, good anti-scratch and anti-wear properties and desirable mechanical properties.
  • the organopolysiloxane resin E’ may constitute a least 3wt%of the total weight of the curable silicone composition, in order to improve mechanical property.
  • the organopolysiloxane E may comprise or basically comprise the organopolysiloxane resin E” in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, yet for example from 1wt%to 45wt%, further for example from 5wt%to 40wt%, and yet more for example from 15wt%to 30wt%, wherein the lower limit may be 0.1wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, or 45wt%or any numerical value contained therebetween, and the upper limit may be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%or any numerical value contained therebetween, based on the total weight of the curable silicone composition
  • the organopolysiloxane E when the organopolysiloxane E is consisted of the organopolysiloxane resin E” , the organopolysiloxane resin E” may constitute from greater than 10wt%to 45wt%, preferably from 15wt%to 40wt%, more preferably from 30wt%to 40wt%of the total weight of the curable silicone composition, so that the obtained post-treated product could exhibit excellent tactility (hand feeling) and matte surface without impairing the mechanical properties of the product.
  • the organopolysiloxane E comprises a combination of at least one organopolysiloxane resin E” and at least one organopolysiloxane resin E’
  • the organopolysiloxane resin E’ may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably in an amount of from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition
  • the organopolysiloxane resin E” may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably from 5wt%to 40wt%, more preferably from 10wt%to 30wt%, and even more preferably from
  • the thus obtained post-treated product may possess very excellent tactility (hand feeling) , anti-wear and anti-scratch properties without impairing mechanical property thereof.
  • both matte or glossy surface may be created by adjusting the proportions of the at least one organopolysiloxane resin E” and at least one organopolysiloxane resin E’, wherein the former may contribute to a matte appearance with the latter may bring about a glossy appearance.
  • the curable silicone composition for post-treatment may comprise a combination of at least one organopolysiloxane resin E’ and at least one filler, wherein the organopolysiloxane resin E’ may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably in an amount of from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition.
  • the at least one filler its detailed information would be discussed hereafter.
  • the curable silicone composition for post-treatment may comprise a combination of at least one organopolysiloxane resin E and at least one filler with the organopolysiloxane resin E is consisted of the organopolysiloxane resin E”, the organopolysiloxane resin E” may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably from greater than 10wt%to 45wt%, more preferably from 15wt%to 40wt%, and even more preferably from 30wt%to 40wt%of the total weight of the curable silicone composition, so that the obtained post-treated product could display matte surface, very excellent (hand feeling) in conjunction with anti-scratch and mechanical properties, especially for superior elongation at break.
  • the at least one filler its detailed information would be discussed hereafter.
  • the curable silicone composition for post-treatment may comprise a combination of at least one organopolysiloxane resin E’ , at least one organopolysiloxane resin E” and at least one filler, wherein the organopolysiloxane resin E’ may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, and even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition, and the organopolysiloxane resin E” may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably from 5wt%to 40wt%, more preferably from 10wt%to 30wt%,
  • the thus obtained post-treated product may have comprehensive superior effects including tactility, either matte or glossy surface, invisible surface texture, anti-wear and anti-scratch properties in addition with mechanical properties.
  • tactility either matte or glossy surface
  • invisible surface texture any surface texture
  • anti-wear and anti-scratch properties in addition with mechanical properties.
  • at least one filler its detailed information would be discussed hereafter.
  • the curable silicone coating composition according to the invention can optionally comprise further components so as to adjust the overall properties of the composition as desired.
  • the curable silicone composition may further comprise at least one filler D, preferably silica such as fumed or precipitated silica, polyamide particles and the mixture thereof.
  • the surface of the precipitated or fumed silica particles may be rendered hydrophobic. Rendering the filler particles hydrophobic may be done either prior to or after dispersing the precipitated or fumed silica particles in the organopolysiloxane component. This can be effected by pre-treatment of the silica particles with the hydrophobing agents like fatty acids, reactive silanes, wax or reactive siloxanes.
  • Examples include but are not limited to stearic acid, dimethyldichloro silane, trimethylchloro silane, hexamethyldisilazane, tetramethyldivinyldisilazane, hydroxyl endblocked or methyl end blocked polydimethylsiloxanes, siloxane resins or mixtures of two or more of these.
  • the precipitated or fumed silica particles which have already been treated hydrophobic are commercially available in the market.
  • Most preferred hydrophobing agent is hexamethyldisilazane or polyethene wax.
  • the specific surface area of the precipitated or fumed silica is from 50-400 m 2 /g, preferably from 100-300 m 2 /g, as determined by a BET method.
  • Polyamide particles which have a spherical shape and the specific particle size D50 as given above are also preferred filler used in the silicone coating composition, providing improved multiple performance aspects of the coating composition, such as abrasion resistance, chemical resistance, gloss reduction, hardness, and also texture creation.
  • suitable polyamide include such as, polyamide 6, polyamide 7, polyamide 9 or polyamide 10, preferably polyamide 6.
  • These polyamide particles have low density which is for example around 1.15g/cm 3 and can be dispersed stably and homogenously in the coating composition.
  • the filler is comprised in an amount of from 0wt%to 30wt%, preferably from 0.1wt%to 30wt%, more preferably from 1wt%to 20wt%, even more preferably from 3wt%to 18wt%, with lower limit possibly being 0.1wt%, 1wt%, 2wt%, 3wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%or any numerical value contained therebetween, and upper limit possibly being 5wt%, 10wt%, 15wt%, 20wt%, 25wt%or any numerical value contained therebetween, based on the total weight of the curable silicone composition.
  • an adhesive promotor preferably in an amount of from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.5wt%to 5wt%, based on the total weight of the curable silicone composition.
  • the adhesive promoter may be one or more selected from epoxy silane, alkoxy silane, acyloxy silane, aryloxy silane or oligomers thereof.
  • They include, but are not limited to, 3-glycidoxypropyl trimethoxy silane, octyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, gamma-methacryloxy-propyltrimethoxysilane, beta- (3, 4-epoxycyclohexyl) -ethyltrimethoxysilane beta- (3, 4-epoxycyclohexyl) -ethyltriethoxysilane and bis (trimethoxysilyl propyl) fumarate, alkoxy or aryloxy silicones such as trimethoxysilyl functional groups modified silicones.
  • the adhesive promoter may be vinyltrimethoxysilane, epoxy-containing Polydimethylsiloxane, triallyl isocyanurate, or a combination thereof.
  • the amount of the adhesive promoter in the silicone coating composition has to be controlled within the scope of 0 to 5 parts, preferably 0 to 3 parts, most preferably 0 parts by total weight of whole composition.
  • the overall properties of the cured silicone coating composition would be notably deteriorated and the preparation for the silicone coating composition would also be adversely affected.
  • Examples of the component that may be additionally contained in the composition include pigment, colorant or other fillers like calcium carbonate, quartz, wollastonite, cerium oxides, Al (OH) 3 , Fe 2 O 3 , Al 2 O 3 , mica, talc, MgO, Mg (OH) 3 , TiO 2 .
  • these fillers are preferably used in an amount of less than 30 %by total weight of whole composition, preferably less than 10 %by weight or more preferably less than 5%or most preferably 0%, since high amount of these fillers will not contribute to any further improvement of the hand feeling and mechanical properties or even make them worse.
  • crosslinking inhibitor which are conventionally employed in polyaddition crosslinking reactions in the silicone field. They may especially be chosen from the following compounds: organopolysiloxanes substituted by at least one alkenyl which may optionally be present in cyclic form, with tetramethylvinyltetrasiloxane being particularly preferred; organic phosphines and phosphites; unsaturated amides; alkylated maleates; and acetylenic alcohols.
  • the crosslinking inhibitor may be 2, 4, 6, 8-Tetramethyl-2, 4, 6, 8-tetravinylcyclotetrasiloxane, ethynylcyclohexanol, 2, 4, 7, 9-Tetramethyl-5-decyne-4, 7-diol, or a combination thereof.
  • acetylenic alcohols they are also preferred thermal blockers for the hydrosilylation reaction.
  • acetylenic alcohols include especially 1-ethynyl-1-cyclohexanol, 3-methyl-1-dodecyn-3-ol, 3, 7, 11-trimethyl-1-dodecyn-3-ol, 1, 1-diphenyl-2-propyn-1-ol, 3-ethyl-6-ethyl-1-nonyn-3-ol, 2-methyl-3-butyn-2-ol, 3-methyl-1-penta-decyn-3-ol, diallyl maleate or derivatives of diallyl maleate or mixture thereof.
  • the amount of the crosslinking inhibitor in the curable silicone composition is in the range from 0wt%to 10wt%, preferably from 0.01 wt%to 8 wt%, more preferably from 0.05wt%to 4wt%, based on the total weight of the curable silicone composition.
  • the use of the inhibitor is effective to avoid the premature curing of the silicone composition on the tip of the nozzle and subsequent disfiguration of the printed layer.
  • the curable silicone composition of the present invention can further comprise one or more additives selected from antistatic agent, radiation shielding agent, free radical inhibitor, adhesive modifier, flame retardant additive, surfactant, storage stability modifier, ozone degradation inhibitor, light stabilizer, viscosity builder, plasticizer, thixotropic agent, antioxidant and heat stabilizer.
  • additives selected from antistatic agent, radiation shielding agent, free radical inhibitor, adhesive modifier, flame retardant additive, surfactant, storage stability modifier, ozone degradation inhibitor, light stabilizer, viscosity builder, plasticizer, thixotropic agent, antioxidant and heat stabilizer.
  • additives selected from antistatic agent, radiation shielding agent, free radical inhibitor, adhesive modifier, flame retardant additive, surfactant, storage stability modifier, ozone degradation inhibitor, light stabilizer, viscosity builder, plasticizer, thixotropic agent, antioxidant and heat stabilizer.
  • other polyorganosiloxanes, siloxane resins, polyorganosilsesquioxanes and silicon rubber powders can also
  • the building material of an object preferably a 3D printed object or the material from which the surface of an object, preferably a 3D printed object is made may be addition type silicone composition, comprising:
  • (C) at least one catalyst C capable of catalyzing or promoting the hydrosilylation reaction between component (A) and component (B) , and
  • curable silicone composition for post treatment may apply also for the building material of 3D printed object or the material from which the surface of the 3D printed object is made.
  • the building material or outermost material for an object may also possess the SiH/Vinyl from 0.5 to 10 mol/mol, preferably from 0.6 to 5 mol/mol, more preferably from 0.8 to 4 mol/mol, from 1.2 to 4 mol/mol or from 1.6 to 4 mol/mol.
  • inventive curable silicone composition for post treatment may have varied compositions, it is essential for such composition to comprise at least one organopolysiloxane E comprising at least one siloxy units T of formula LSiO 3/2 and/or at least one Q of formula SiO 4/2 with L defined as above, in particular MD Vi Q and/or MM Vi Q.
  • the curable silicone composition for post-treating a surface of an object preferably a 3D printed object, comprising:
  • component (C) from 10 to 500 ppm, preferably from 20 to 400ppm, more preferably from 50 to 200 ppm of at least one catalyst C capable of catalyzing the hydrosilylation reaction between component (A) and component (B) ;
  • the curable silicone composition may further comprise a solvent.
  • the solvent is selected from:
  • non-reactive polyorganosiloxanes such as isodecamethylcyclopentasiloxane, octamethylcyclotetrasiloxane or a combination thereof;
  • the amount of solvent used may be selected through conventional means or depending on particular application.
  • the solvent is comprised in an amount of from 0.99wt%to 99wt%, preferably from 16.7wt%to 90.9wt%, more preferably from 28.6wt%to 83.3wt%, the wt%is based on the total weight of the curable silicone composition.
  • the inventive curable silicone composition for post-treatment is comprised of the components (A) to (G) and solvent as indicated above, wherein the total amount for components (A) to (G) and solvent is equivalent to 100wt%.
  • the inventive post treatment silicone composition or the article treated thereby is suitable for the medical application such as an additive manufactured medical device or prosthetic appliance.
  • the curable silicone composition used for the post treatment may be identical to or different from the material from which the surface of the object is made.
  • both the curable silicone compositions and the material from which the surface of the object is made may be addition type silicone composition.
  • the present disclosure refers to a 3D printing process comprising the following steps:
  • the object has a surface made of polymeric material, preferably the object is made of polymeric material, more preferably made of silicone material,
  • the entire 3D printed object is made of a polymeric material.
  • a 3D printed object may be carried out in varied ways as long as a coating or a layer may be formed covering the exterior surface to be treated.
  • the object preferably the 3D printed object obtained from 3D printing process may be dipped into a bath of the curable silicone composition for post-treatment.
  • the dip coating may be carried out at varied temperatures, in particular at the room temperature. Finally, the dip coated object is taken out from the bath and allowed to be cured.
  • the coated curable silicone composition may be then cured at room temperature or under heat or UV radiation.
  • the employed temperature may be from room temperature (about 23°C) up to for example 150°C.
  • any UV light source may be employed such as a LED lamp or mercury lamp as long as it can provide the sufficient energy to cure the curable silicone composition.
  • the UV curing may be conducted for 0.001 s to 30 min, in particular for 0.1 s to 2min.
  • Viscosity According to ASTM D445, the viscosity of the curable silicon composition is tested at 23°C, the details of testing conditions can be seen in Tables 3, in which, for example, the expression (5#, 10 rpm) means that the viscosity is measured at 10 rpm by using spindle number 5, and so on.
  • Hardness The hardness of the cured samples obtained by curing the curable silicone composition of Examples 1-9 at 150°C for 1 h was measured at 23°C according to ASTM D2240.
  • Tensile strength and Elongation at break Tensile strength and Elongation at break of cured samples obtained by curing the curable silicone composition of Examples 1-9 at 150°C for 1 h were measured at 23°C according to ASTM D412.
  • Anti-wear property of 3D printed object after post-treatment with the curable silicone composition of Examples 1-1 to Example 9-1 was evaluated by a wear tester using Taber 5135 according to ASTM D4060-19 with Test mode of 2000 cycles.
  • Scratch resistance Scratch resistance of 3D printed object after post-treatment with the curable silicone composition of Examples 1-1 to Examples 9-1 was expressed by the proportion of surface area worn out by scratch to the original surface area.
  • glossiness refers to the state of matte( ⁇ ) or gloss( ⁇ ) .
  • the state of surface texture, transparency, and the degree of slippery( ⁇ ) in hand feeling are graded with asterisks.
  • Example 1 was prepared as follows: 8.39 parts of A-1, 27.62 parts of A-3, 13.59 parts of A-4, 4.8 parts of A-5 were mixed with 6.36 parts of B-1 under agitation. Then 3.43 parts of D-1 and 8.72 parts of E-1 and 26.68 parts of E-3 were added into the above mixture, followed by addition of 0.4 parts of G-2 with through stirring. Finally, 0.015 parts of catalyst C-1 was added to obtain Example 1.
  • Example 2-9 was likewise prepared according to Example 1 except varying the amounts of the components as shown in Tables 3.
  • Comparative Example was a reference example wherein the 3D printed object was not post treated by the inventive curable silicone composition.
  • the 3D printed sample was dipped into the above bath for post-treatment and then was left to stay at room temperature for 5 minutes in a dust-free environment until a uniform coating layer is obtained without any droplet dripping from the article. Then, the coated 3D printed sample was placed in an oven at 150°C and subjected to curing for 30 minutes before taken out for cooling.
  • the Comparative Example has obtained 3D printed sample with obvious visible surface texture, poor transparency and rough surface in tactility.
  • the 3D printed object after post-treatment with the inventive curable silicone composition comprising the essential component E has exhibited a variety of good performances.
  • the thus obtained post-treated object was slippery in hand feeling with invisible surface texture while maintaining the desired mechanical properties of the coating. What’s more, thus obtained post-treated object was more resistant to wear and scratch. Besides, both the surface state of matte and glossy may be achieved which are suitable for varied intended application.
  • inventive curable silicone composition comprising organopolysiloxane resin E’, it enables the thus obtained object significantly increased wear resistance and scratch resistance which is of great beneficial when in use.
  • inventive curable silicone composition comprising organopolysiloxane resin E” (e.g. Examples 4)
  • very excellent tactility is achieved together with surface state of matte without impairing the mechanical property.
  • inventive curable silicone composition comprising organopolysiloxane resin E” and organopolysiloxane resin E’ (e.g. Example 6)
  • organopolysiloxane resin E e.g. Example 6
  • very excellent tactility is observed together with excellent anti-wear and anti-scratch properties and desirable mechanical properties.
  • inventive curable silicone composition comprising organopolysiloxane resin E” and filler (e.g. Example 5)
  • very excellent tactility hand feeling
  • organopolysiloxane resin E As for the inventive curable silicone composition comprising organopolysiloxane resin E” , organopolysiloxane resin E’ and filler (e.g. Example 1) , comprehensive superior effects would be achieved including tactility, either matte or glossy surface, invisible surface texture, anti-wear and anti-scratch properties in addition with mechanical properties.

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Abstract

The invention relates to a method for post-treating the surface of an object, preferably a 3D printed object, comprising the steps of applying a coating of a curable silicone composition to at least part of the surface of the object and then curing the coating, wherein the curable silicone composition comprises at least one organopolysiloxane E comprising at least one siloxy units T of formula LSiO3/2 and/or at least one siloxy unit Q of formula SiO4/2.

Description

METHOD FOR POST-TREATING AN OBJECT TECHNICAL FIELD
The invention relates to a method for post-treating an object, preferably a 3D printed object with a curable silicone composition, a post-treatment agent and a 3D printing process comprising such a method.
BACKGROUND OF THE INVENTION
In recent years, additive manufacturing (AM) technique, also referred to 3D printing technology has developed rapidly, which makes it possible to manufacturing objects more efficiently compared to conventional methods due to layer-by-layer deposition. Such technique possesses varies advantages, for example reduced production cycle, enhanced material utilization, customized production of complex, special-shaped objects and so on. In practice, several materials can be printed via 3D printing technology such as metal, polymers or ceramic. Among them, silicone materials may be used by means of extrusion 3D printing technology and UV curable printing technology.
When 3D printed objects are manufactured with silicone materials, it has been found several drawbacks with respect to the surface of printed objects: visible surface texture due to layer-by-layer deposition; not slippery in hand feeling; poor anti-wear property and/or scratch resistance. Among them, hand feeling, or in other words, tactility is a characteristic different from transparency or smooth. As known in the art, 3D printed objects with transparent appearance do not necessarily lead to good hand feeling. Likewise, even if surface texture of a 3D printed object is smooth with less or even invisible surface texture, the hand feeling might still be undesirable.
Although certain prior arts refer to 3D printed objects with silicone as building materials, they are basically focused on the development of silicone materials, printing equipment and process. There are little relevant or feasible post-treatment method for an object, preferably a silicone 3D printed object.
US20220080684A1 disclose a method for cleaning and post-processing 3D printed silicones, comprising a) providing a 3D printed part; b) immersing the part into a first liquid medium  that is incompatible with the material from which the part is made from, and c) exposing the part to ultrasound. Wherein the solvent used not only removes excess resin, but also ensures dimensional stability as well as oxygen elimination, thereby facilitating surface curing of the part. However, this reference is not intended to improve the surface condition of the 3D printed objects.
US10625292B2 discloses a system for treating uneven surfaces of additive manufactured objects which may improve the transparency and glossiness of the surfaces. The system operates a sprayer to apply fluid material to the uneven surface so as to smooth the surface, or otherwise the system operates an actuator to dip the additive manufactured object into a bath of such a fluid material. No information on the chemical composition of useful fluid material is given.
WO2019127453A1 discloses a method for remedying the ladder-like appearance on the surface of 3D printed objects, comprising the steps of S1) coating a surface of the substrate with an uncured resin liquid; S2) applying a uniform pressure to the surface of the substrate through the transparent film, the pressure causes the uncured resin liquid to fill the surface gap of the substrate, and flat the surface of the entire uncured resin liquid; S3) curing the uncured resin liquid by UV while maintaining the pressure, to obtain a smooth resin surface; S4) the entire substrate is subjected to heat annealing to eliminate the internal stress of the substrate to achieve uniform performance for the substrate. Although problem of surface roughness might be resolved here, it is realized by means of special processing step (uniform pressure) , rather than the selection of post-treatment.
There continues to be a need for an improved method for post-treating an object, preferably a 3D printed object which lead to slippery in hand feeling and improved wear and scratch resistance for thus obtained object.
SUMMARY OF INVENTION
The object of the invention is to provide a method for post-treating a surface of an object, preferably a 3D printed object. After the post-treatment, thus obtained post-treated object is much slippery in hand feeling. Moreover, more resistant to scratch and/or wear of the post-treated object are achieved by present method. In addition, matte or glossy surface is exhibited which is useful for varied applications.
It has been surprisingly found by present inventors that an object, preferably a 3D printed object having significant improved surface condition and anti-wear and/or anti-scratch property can be obtained by applying the inventive curable composition comprising at least one organopolysiloxane E to the surface of the object followed by curing, wherein organopolysiloxane E comprises at least one siloxy unit T of formula LSiO3/2 and/or at least one siloxy unit Q of formula SiO4/2 with L denotes OH or organic group.
For example, L may denote OH, C1-20 alkoxy, C1-20 alkyl, C2-20 alkenyl, C6-20 aryl, each of the C1- 20 alkoxy, C1-20 alkyl, C2-20 alkenyl and C6-20 aryl is optionally substituted with at least one group selected from OH, C1-6 alkyl, C6-C10 aryl, epoxy group, and acrylate group.
For example, L may denote OH, C1-12 alkoxy, C1-12 alkyl, C2-12 alkenyl, C6-10 aryl, the C1-12 alkyl is optionally substituted with at least one group selected from epoxy group, and acrylate group.
For example, L may denote OH, methoxy, ethoxy, methyl, ethyl, vinyl, epoxy group substituted C1-6 alkyl, or acrylate group substituted C1-6 alkyl.
For example, L may denote methyl or vinyl.
Wherein L in each siloxy unit T may be identical to or different from each other when more than more siloxy unit T are present.
Therefore, in a first aspect, the present disclosure relates to a method for post-treating a surface of an object, preferably a 3D printed object, comprising the steps of
i) applying a coating of a curable silicone composition to at least part of the surface of the object; and
ii) curing the coating,
wherein the curable silicone composition comprises at least one organopolysiloxane E comprising at least one siloxy unit T of formula LSiO3/2 and/or at least one siloxy unit Q of formula SiO4/2 with L defined as above.
The object to be post-treated may be any object. In particular, the object to be post-treated may be made of silicone, plastic, metal or ceramic and the like, depending on applications. One example of such object may be a medical device, preferably an additive manufactured medical device. In particular, the medical device may be selected from catheters, implantable  biosensors, or prosthesis. Preferably, the medical device may be prosthesis such as hip prosthesis, knee prosthesis, or breast prosthesis etc. Another example of such object may be fabric, especially silicone-made fabric, from which a variety of wearable consumer products including clothes, shoes, hats, bags and luggage, or ornaments and so on could be produced. In that condition, the post-treated fabric with inventive curable composition may exhibit good hand feeling (tactility) , either matte or glossy surface together with proper mechanical property to meet various needs in consumer products. Further example of such object to be post-treated may be skin-like material, especially those made of silicone, which could be used to manufacture human-mimic products for example robots, dolls, or mannequins for window display to mimic human skin. For these applications, slippery hand-feeling and matte or glossy surface are essential and desirable which could be realized by post-treatment with inventive curable composition.
With the inventive method, the object after post-treatment has exhibited much slippery in hand feeling, increased wear and scratch resistance, matte or glossy surface with surface texture resulted from layer-by-layer deposition invisible. The component organopolysiloxane E is essential for the inventive method. The intended effect of present invention as mentioned above would not be achieved, in absence of the essential component. In a second aspect, the present disclosure relates to a curable silicone composition used in the first aspect of present disclosure.
In a third aspect, the present disclosure relates to use of the curable silicone composition as mentioned in the first or second aspect of present disclosure for imparting at least one of glossy or matte surface, improved hand feeling, improved anti-wear and anti-scratch properties to an object, preferably a 3D printed object, more preferably a 3D printed silicone object.
In a fourth aspect, the present disclosure relates to a post-treatment agent comprising or basically consisting of the curable silicone composition as mentioned in the first or second aspect of present disclosure.
In a fifth aspect, the present disclosure relates to a 3D printing process comprising the following steps:
i’) fabricating an object by a 3D printing method, wherein the object has a surface made of  polymeric material, preferably the object is made of polymeric material, more preferably made of silicone material,
ii’) post-treating the surface of the object by the method according to the first aspect of present disclosure.
In a sixth aspect, the present disclosure refers to medical devices, wearable consumer products, or human-mimic products having skin-like appearance, with the surface of which treated by the method according to the first aspect of the present disclosure.
Preferably, the medical device may be an additive manufactured medical device. By way of example, the medical device may be selected from catheters, implantable biosensors, or prosthesis. Preferably, the medical device may be prosthesis such as hip prosthesis, knee prosthesis, or breast prosthesis etc.
Preferably, the wearable consumer products may be selected from clothes, shoes, hats, bags and luggage, or ornaments. Preferably, the wearable consumer products are made from additive manufacture process.
Preferably, the human-mimic products may be selected from robots, dolls, or mannequins for window display. Preferably, the human-mimic products are made from additive manufacture process.
In a seventh aspect, the present disclosure refers to an article made of silicone, plastic, metal or ceramic, comprising a surface treated by the method according to the first aspect of present disclosure. Preferably, the article may be an additive manufactured article.
DESCRIPTION OF FIGURES
Figure 1 depicts the structure of a 3D printed ring in accordance with present invention.
Figure 2 depicts the comparison of 3D printed object with inventive post treatment according to Example 1-1 vs. the 3D printed object without the inventive post treatment
EMBODIMENTS OF INVENTION
Definition
All the viscosities under consideration in the present specification correspond to a dynamic viscosity magnitude that is measured, in a manner known per se, at about 23℃, with a machine of e.g., Brookfield type, in accordance with ASTM D445. As regards to fluid products, the viscosity under consideration in the present specification is the dynamic viscosity at  about 23℃, known as the “Newtonian” viscosity, i.e., the dynamic viscosity that is measured, in a manner known per se, at a sufficiently low shear rate gradient so that the viscosity measured is independent of the rate gradient.
If appearing herein, the term "comprising" and derivatives thereof are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is disclosed herein. In order to avoid any doubt, all compositions claimed herein through use of the term "comprising" may include any additional additive, adjuvant, or compound, unless stated to the contrary. In contrast, the term, "basically consisted of” , “basically consisting of” , “basically comprising” or “basically comprises” if appearing herein, excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability and the term " consisting of” or “consisted of” , if used, excludes any component, step or procedure not specifically delineated or listed. The term "or" , unless stated otherwise, refers to the listed members individually as well as in any combination.
Unless otherwise specified, the term "hydrocarbon group” refers to a linear, branched chain or cyclic hydrocarbon radical or any combination thereof. The term " hydrocarbon group” includes, but is not limited to, aliphatic hydrocarbyl and aromatic hydrocarbyl.
3D printing
3D printing is generally associated with a host of related technologies used to fabricate physical object from computer generated, e.g., computer-aided design (CAD) , data sources.
This disclosure generally incorporates ASTM Designation F2792-12a, "Standard Terminology for Additive Manufacturing Technologies Under this ASTM standard.
"3D printer" is defined as "a machine used for 3D printing" and "3D printing" is defined as "the fabrication of objects through the deposition of a material using a print head, nozzle, or another printer technology. "
"Additive manufacturing (AM) " is defined as "a process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies. Synonyms associated with and encompassed by 3D printing include additive  fabrication, additive processes, additive techniques, additive layer manufacturing, layer manufacturing, and freeform fabrication. " Additive manufacturing (AM) may also be referred to as rapid prototyping (RP) . As used herein, "3D printing" is generally interchangeable with "additive manufacturing" and vice versa.
“Printing” is defined as depositing of a material, here a silicone composition, using a print head, nozzle, or another printer technology.
In present disclosure “3D or three-dimensional printed article, object or part” means an article, object or part obtained by additive manufacturing or 3D printing as disclosed above.
In general, all 3D printing processes have a common starting point, which is a computer-generated data source or program which may describe an object. The computer-generated data source or program can be based on an actual or virtual object. For example, an actual object can be scanned using a 3D scanner and scan data can be used to make the computer-generated data source or program. Alternatively, the computer-generated data source or program may be designed from Scratch.
The computer-generated data source or program is typically converted into a standard tessellation language (STL) file format; however other file formats can also or additionally be used. The file is generally read into 3D printing software, which takes the file and optionally user input to separate it into hundreds, thousands, or even millions of "slices. " The 3D printing software typically outputs machine instructions, which may be in the form of G-code, which is read by the 3D printer to build each slice. The machine instructions are transferred to the 3D printer, which then builds the object, layer by layer, based on this slice information in the form of machine instructions. Thicknesses of these slices may vary.
An extrusion 3D printer is a 3D printer where the material is extruded through a nozzle, syringe or orifice during the additive manufacturing process. Material extrusion generally works by extruding material through a nozzle, syringe or orifice to print one cross-section of an object, which may be repeated for each subsequent layer. The extruded material bonds to the layer below it during cure of the material.
In one preferred embodiment, the method for additive manufacturing a three-dimensional  elastomer article uses an extrusion 3D printer. The additive manufacturing material like silicone compositions are extruded through a nozzle. The nozzle may be heated to aid in dispensing the silicone composition.
The average diameter of the nozzle defines the thickness of the layer. In an embodiment, the diameter of the layer is comprised from 5 to 5000 μm, preferably from 10 to 2000 μm and most preferably from 50 to 1000 μm.
The distance between the nozzle and the substrate is an important parameter to assure good shape. Preferably it is comprised from 60 to 150 %, more preferably from 80 to 120 %of the nozzle average diameter.
The silicone composition to be dispensed through the nozzle may be supplied from a cartridge-like system. The cartridge may include a nozzle or nozzles with an associated fluid reservoir or fluids reservoirs. It is also possible to use a coaxial two cartridges system with a static mixer and only one nozzle. Pressure will be adapted to the fluid to be dispensed, the associated nozzle average diameter and the printing speed.
Because of the high shear rate occurring during the nozzle extrusion, the viscosity of the silicone compositions is greatly lowered and so permits the printing of fine layers.
Cartridge pressure could vary from 1 to 20 bars, preferably from 2 to 10 bar and most preferably from 2.5 to 8 bar. An adapted equipment using aluminum cartridges shall be used to resist such a pressure.
The nozzle and/or build platform moves in the X-Y (horizontal plane) to complete the cross section of the object, before moving in the Z axis (vertical) plane once one layer is complete. The nozzle has a high X-Y-Z movement precision such as 10～300μm. After each layer is printed in the X, Y work plane, the nozzle is displaced in the Z direction only far enough that the next layer can be applied in the X, Y work plane. In this way, the object which becomes the 3D article is built one layer at a time from the bottom upwards.
As disclosed before, the distance between the nozzle and the previous layer is an important parameter to assure good shape. Preferably, it should be comprised from 60 to 150 %,  preferably from 80 to 120 %of the nozzle average diameter.
Advantageously, printing speed is comprised between 0.1 and 100 mm/s, preferably between 1 and 50 mm/s to obtain the best compromise between good accuracy and manufacture speed.
"Material jetting" is defined as "an additive manufacturing process in which droplets of build material are selectively deposited. " The material is applied with the aid of a printing head in the form of individual droplets, discontinuously, at the desired location of the work plane (Jetting) . 3D apparatus and a process for the step-by-step production of 3D structures with a printing head arrangement comprising at least one, preferably 2 to 200 printing head nozzles, allowing the site-selective application where appropriate of a plurality of materials. The application of the materials by means of inkjet printing imposes specific requirements on the viscosity of the materials.
In a material 3D jetting printer one or a plurality of reservoirs are subject to pressure and being connected via a metering line to a metering nozzle. Upstream or downstream of the reservoir there may be devices which make it possible for multicomponent addition-crosslinking silicone compositions to be homogeneously mixed and/or to evacuate dissolved gases. One or a plurality of jetting apparatuses operating independently of one another may be present, to construct the elastomer article from different addition-crosslinking silicone compositions, or, in the case of more complex structures, to permit composite objects made from silicone elastomers and other plastics.
Because of the high shear rate occurring in the metering valve during the jetting metering procedure, the viscosity of such silicone compositions is greatly lowered and so permits the jetting metering of very fine microdroplets. After the microdroplets have been deposited on the substrate, there is a sudden reduction in its shear rate, and so its viscosity increases again. Because of this, the deposited drop rapidly becomes of high viscosity again and permits the shape-precise construction of three-dimensional structures.
The individual metering nozzles can be positioned accurately in x-, y-, and z-directions to permit precisely targeted deposition of the silicone composition drops on the substrate or, in the subsequent course of formation of shaped objects, on the silicone rubber composition  which has already been placed and which optionally has already been crosslinked.
Typically, the 3D printer utilizes a dispenser, e.g., a nozzle or print head, for printing the particular curable silicone composition. Optionally, the dispenser may be heated before, during, and after dispensing the silicone composition. More than one dispenser may be utilized with each dispenser having independently selected properties.
In one embodiment, this method can use support material to build the object. If the object is printed using support material or rafts, after the printing process is complete, they are typically removed leaving behind the finished object.
In one embodiment, the 3D printing process may comprise extruding or jet printing.
In one embodiment, the 3D printing process may comprise UV curing process such as UV-Stereolithography (SLA) , UV-Digital Light processing (DLP) , Continuous Liquid Interface Production (CLIP) , UV-extrusion and Inkjet Deposition.
Building material
In the present disclosure, the useful building material for an object, preferably an 3D printed object may contain polymer material, ceramic, metal material, and preferably based on or basically consisting of the polymer material (such as silicone or plastic) , especially curable silicone composition. The silicone compositions available are well known and in principle may be any curable silicone composition that has the siloxy units-based backbone and can be used for producing a silicone elastomer article, such as the liquid silicone rubber (LSR) which has been already used widely. When using different printing materials to make an object, preferably an additive manufactured object which thus may be composed of several parts based on different materials, at least part of its exterior surface is preferably made of polymeric material, in particular the silicone rubber.
The suitable silicone composition used as building material, including silicone rubber, may be curable chemically via condensation or addition crosslinking reactions. In one exemplary embodiment, such a curable silicone composition usually comprises:
(A) a polyorganosiloxane polymer containing the siloxy unit represented by the formula (S-1) and optionally formula (S-2)
LS aNS bSiO [4- (a+b) ] /2   (S-1)
in which
- LS is a reactive group like hydroxyl, alkoxy, alkenyl, and alkynyl groups,
- NS may be the same or different and each represent a monovalent non-reactive hydrocarbon radical having for example from 1 to 30 carbon atoms, preferably selected from alkyl and aryl groups,
- a is an integer of 1, 2 or 3, b is an integer of 0, 1 or 2 and the sum of a + b is 1, 2 or 3;
NS1 cSiO (4-c) /2        (S-2)
in which:
- c is an integer of 0, 1, 2 or 3,
- NS1 may be identical or different and represent a monovalent non-reactive hydrocarbon radical having for example from 1 to 30 carbon atoms, preferably selected from alkyl and aryl groups,
(B) a cross-linking organosilicon compound having at least 2 silicon-bonded reactive groups; (C) a catalyst capable of promoting the reaction between component (A) and component (B) , and
(E) optional organopolysiloxane E as mentioned below.
Curable silicone composition
In the present disclosure, a coating of curable silicone composition may be applied to at least part of the exterior surface or fabricated edges of an object, preferably a 3D printed object, followed by curing at room temperature or under heat or UV radiation.
The term “applying” or “applied” used herein is well known to the skilled person and refers to all application forms or ways which allows the curable silicone composition to cover sufficiently the exterior surface or fabricated edges of an object, preferably a 3D printed object to be post-treated. By way of examples, the applying includes dip coating for example dipping into a treatment bath of the curable silicone composition, spraying coating, curtain coating or spinning coating or any other manners, preferably dip coating.
In a preferred embodiment, the curable silicone composition used for post treatment may comprises
(A) at least one organopolysiloxane compound A comprising, per molecule at least two alkenyl radicals bonded to silicon atoms,
(B) at least one organohydrogenopolysiloxane compound B comprising, per molecule, at least two hydrogen atoms bonded to an identical or different silicon atom, and
(C) at least one catalyst C capable of catalyzing or promoting the hydrosilylation reaction between component (A) and component (B) ;
(E) at least one organopolysiloxane E comprising at least one siloxy unit T of formula LSiO3/2 and/or at least one siloxy unit Q of formula SiO4/2,
wherein L denotes OH or organic group.
For example, L may denote OH, C1-20 alkoxy, C1-20 alkyl, C2-20 alkenyl, C6-20 aryl, each of the C1- 20 alkoxy, C1-20 alkyl, C2-20 alkenyl and C6-20 aryl is optionally substituted with at least one group selected from OH, C1-6 alkyl, C6-C10 aryl, epoxy group, and acrylate group.
For example, L may denote OH, C1-12 alkoxy, C1-12 alkyl, C2-12 alkenyl, C6-C10 aryl, the C1-12 alkyl is optionally substituted with at least one group selected from epoxy group, and acrylate group.
For example, L may denote OH, methoxy, ethoxy, methyl, ethyl, vinyl, epoxy group substituted C1-6 alkyl, or acrylate group substituted C1-6 alkyl.
For example, L may denote methyl or vinyl.
Wherein L in each siloxy unit T may be identical to or different from each other when more than one siloxy unit T are present.
Organopolysiloxane compound A
The organopolysiloxane compound A is at least one organopolysiloxane polymer having at least two alkenyl radicals bonded to silicon atoms. The alkenyl radicals may be at any position on the chain (e.g. main chain) of organopolysiloxane, for example, at the ends or in the middle of the main chain, or both at the ends and in the middle of the main chain.
In the context of the present disclosure, the term “alkenyl radical” refers to the radical of a C-C double bond (i.e. -C=C-) and thus the alkenyl radical usually includes any hydrocarbon radical such as aliphatic, cycloaliphatic, aromatic, arylaliphatic radical that has at least one C-C double bond. For example, the aliphatic alkenyl groups like vinyl or allyl, or the arylalkenyl groups such as styryl can be regarded as an alkenyl radical. In the present disclosure, the alkenyl radical is able to react with the hydrogen bonded to Si-atom under an  addition reaction like hydrosilylation.
Preferably, the organopolysiloxane compound A comprises:
(I) at least two siloxy units of Formula (I-1) ,
L1 a’Nb’SiO [4- (a’+b’) ] /2    (I-1)
wherein
- L1 represents a monovalent radical containing from 2 to 12 carbon atoms, having at least one alkenyl radical,
- N may be the same or different and each represents a monovalent radical containing from 1 to 20 carbon atoms and does not comprise an alkenyl radical,
- a’ is an integer of 1 or 2, b’ is an integer of 0, 1 or 2, and the sum of a’ + b’ is 1, 2 or 3, and optionally (II) other siloxy units of Formula (I-2)
Nc’SiO (4-c’) /2     (I-2)
wherein
- N has the same meanings as indicated above;
- C’ is an integer of 0, 1, 2 or 3.
Advantageously, the organopolysiloxane compound (A) may substantially or entirely consist of the siloxy units of formulae (I-1) and (I-2) .
The organopolysiloxane compound may be of a linear, branched or cyclic structure. The skilled persons understand that in case of linear or branched structure the organopolysiloxane polymer may be terminated by group –RT or –SiRT 3 wherein RT, independently from each other, denotes a hydrocarbonyl group such as alkyl, alkoxy, alkenyl or aryl.
In context of the present disclosure, the monovalent radical includes preferably hydrocarbonyl group or radical consisting of C, H and O atoms, such as alkyl, alkoxy, (meth) acrylic, alkenyl or aryl groups, that may be linear, branched or cyclic and may be substituted by one or more substituents like halogen atoms. In case of a radical or hydrocarbonyl radical having at least one alkene functional group, at least one C-C bond in the radical may be replaced by C=C double bond.
In the context of the present disclosure, alkyl and alkoxy groups may advantageously have 1  to 18, more preferably 1 to 12, most preferably 1 to 8 carbon atoms and may be unsubstituted or substituted by halogens like fluorine. Examples of alkyl and alkoxy groups include methyl, ethyl, propyl, 3, 3, 3-trifluoropropyl, methoxy and ethoxy groups. Alkenyl groups may preferably have 2 to 12, more preferably 2 to 8 carbon atoms and thus include for example vinyl, propenyl and allyl groups. Aryl groups may have preferably 6 to 20, more preferably 6 to 12 carbon atoms and may be unsubstituted or substituted by halogens like fluorine. Thus, examples of aryl group include phenyl, tolyl, xylyl or naphthyl group.
Group L1 is preferably selected from alkenyl groups, such as vinyl or allyl.
Group N is preferably selected from alkyl, alkoxy and aryl groups. In one exemplary embodiment, Z is selected from C1-C8 alkyl group, and/or C6-C20 aryl groups.
Examples of the units of formula (I-1) may include, but not limited to, vinyl dimethylsiloxy, vinylphenylmethylsiloxy, vinyl methylsiloxy and vinyl siloxy units.
The examples of the unit of formula (I-2) may include, but not limited to, SiO4/2 unit, dimethyl siloxy, methyl phenyl siloxy, diphenyl siloxy, methyl siloxy and phenyl siloxy group.
Examples of the organopolysiloxane compound (A) may include, but not limited to, linear or cyclic compounds such as dimethylpolysiloxane (including dimethylvinylsilyl end group) , (methylvinyl) (dimethyl) polysiloxane copolymers (including trimethylsilyl end group) , (methylvinyl) (dimethyl) polysiloxane copolymers (including dimethylvinylsilyl end group) and cyclic methyl vinyl polysiloxane.
The organopolysiloxane compound A may have a alkenyl content (such as vinyl content) of 0.0001～40wt. %, preferably 0.001～35wt%, more preferably 0.01～30wt%, based on the total weight of organopolysiloxane compound A.
Organohydrogenpolysiloxane compound B
According to a preferred embodiment, the organohydrogenopolysiloxane compound B is an organopolysiloxane containing at least two hydrogen atoms per molecule, bonded to an identical or different silicon atom, so as to perform hydrosilylation reaction with organopolysiloxane compound A.
According to the present invention, the SiH group in organohydrogenopolysiloxane compound B can be at any position of the chain (such as main chain) of organohydrogenopolysiloxane, for example, at ends or in the middle of the molecular chain, or both at ends and in the middle of the molecular chain.
Advantageously, the organohydrogenopolysiloxane compound B is an organopolysiloxane comprising:
(i) at least two siloxy units and preferably at least three siloxy units having the following formula:
Hd’L2 e’SiO [4- (d’+e’) ] /2   (II-1)
wherein
- d’ is an integer of 1 or 2 or 3, e’ is an integer of 0, 1 or 2, and the sum of (d+e) is an integer of 1, 2 or 3;
- L2 represents identically or differently a monovalent linear, branched or cyclic alkyl group containing from 1 to 30 carbon atoms, preferably selected from C1-8 alkyl groups including alkyl groups optionally substituted with at least one halogen atom, and from aryl groups, especially C6-20 aryl groups, and chosen from the group formed by methyl, ethyl, propyl, 3, 3, 3-trifluoropropyl, and
(ii) optionally at least one siloxy unit having the following formula:
L2 f’SiO (4-f’) /2    (II-2)
in which:
- L2 has the same meanings as indicated above
- f’ is an integer of 0, 1, 2 or 3.
In a more preferred embodiment, L2 can be selected from methyl, ethyl, propyl, 3, 3, 3-trifluoropropyl, phenyl, xylyl and tolyl.
The organohydrogenopolysiloxane compound B may be formed solely from siloxy units of formula (II-1) or may also comprise units of formula (II-2) . It may have a linear, branched or cyclic structure.
Examples of siloxy units of formula (II-1) are especially the following units: H (CH3) 2SiO1/2, and HCH3SiO2/2.
When they are linear polymers, they are essentially formed from:
- siloxy units "D" chosen from the units having the following formulae L2 2SiO2/2 or L2HSiO2/2, and
- siloxy units "M" chosen from the units having the following formulae L2 3SiO1/2 or L2 2HSiO1/2.
These linear organopolysiloxanes may be oils with a dynamic viscosity from about 1 to 1000000 mPa. s at 25℃, generally from about 1 to 50000 mPa. s at 25℃ or preferably from about 5 to 10000 or 5000 mPa. s at 25℃.
Examples of organohydrogenopolysiloxane compound B include, but not limited to, linear or cyclic compounds, for example, dimethyl polysiloxane having hydrogenated dimethyl siloxy end group, copolymer having (dimethyl) (hydrogenmethyl) polysiloxane units having trimethyl siloxy end group, copolymer having (dimethyl) (hydrogenmethyl) polysiloxane units having hydrogenated dimethyl siloxy end group, hydrogenated methyl polysiloxane having trimethylsiloxy end group, and cyclic hydrogenated methyl polysiloxane.
The organohydrogenopolysiloxane compound B may be a three-dimensional net-like organohydrogensiloxane resin containing at least two different units selected from the group comprising or consisting of
- units M of formula L’3SiO1/2,
- units D of formula L’2SiO2/2,
- units T of formula L’SiO3/2 and
- units Q of formula SiO4/2, wherein L’ represents hydrogen atom or a monovalent hydrocarbonyl group having from 1 to 20 carbon atoms, and
with the proviso that at least one of these siloxy units is the siloxy unit T or Q, preferably Q, and at least one of the siloxy units M, D and T comprises a hydrogen atom.
In one preferred embodiment, the mole ratio of M unit to Q unit in the organohydrogensiloxane resin B is from 0.5 to 8 mol/mol, preferably from 0.5 to 6 mol/mol, more preferably from 0.8 to 5 mol/mol.
In another exemplary embodiment, the mass content of SiH is between 0.001 wt%and 70  wt%, preferably between 0.5 wt%and 60 wt%and more preferably between 1.0 wt%and 50 wt%, based on the total weight of component B.
Catalyst C
Catalyst C comprises at least one metal from the platinum group or the compound thereof. The platinum metal catalyst is well known in organosilicon field and commercially available. In addition to platinum, the platinum group metal can further comprise ruthenium, rhodium, palladium, osmium and iridium. The catalyst can be composed of following components: a platinum group metal or compound thereof or a combination thereof. Examples of such a catalyst include but not limited to: platinum black, chloroplatinic acid, platinum dichloride, reaction product of chloroplatinic acid with monohydric alcohol. Preferably, compounds of platinum and rhodium are used. Usually, the preferred catalyst is platinum.
Some suitable complexes and compounds of platinum are disclosed in, for example, patents US3159601A, US3159602A, US3220972A, EP0057459A, EP0188978A and EP0190530A, and especially a complex of platinum and vinyl organosiloxane as disclosed in, for example, patents US3419593A, US3715334A, US3377432A and US3814730A can be used. All these documents are incorporated in its entirety in the present specification by reference.
The platinum catalyst ought preferably to be used in a catalytically sufficient amount, to allow sufficiently rapid crosslinking at room temperature. Typically, 1 to 10000 ppm by weight of the catalyst are used, based on the amount of Pt atom, preferably 1 to 100 ppm by weight, more preferably 1 to 50 ppm by weight, relative to the total weight of the curable silicone composition.
In addition, UV curing may be advantageous in some cases. Thus, the silicone composition may contain those catalysts suitable for UV curing, such as platinum-based photo-curing catalysts. Examples of suitable platinum-based photo-curing catalysts include: bis (acetylacetonate) platinum, trimethyl (acetylacetonate) platinum complex, trimethyl (2, 4-pentanedione) platinum complex, trimethyl (3, 5-heptanedione) platinum complex, trimethyl (methyl acetoacetate) platinum complex, bis (2, 4-pentanedione) platinum complex , bis (2, 4-hexanedione) platinum complex, bis (2, 4-heptanedione) platinum complex, bis (3, 5-heptanedione) platinum complex and bis (1-phenyl-1, 3-butanedione) platinum complex and the like.
In the case of UV curing, the amount of the platinum-based photo-curing catalyst is 1-50000 ppm, preferably 5-1000 ppm, based on the total weight of the entire silicone composition, based on platinum metal.
If necessary, when using the platinum-based photo-curing catalyst, an appropriate solvent can be added to dissolve it. Suitable solvents include 2- (2-butoxyethoxy) ethyl acetate, diethylene glycol butyl ether acetate, various halogenated hydrocarbons and the like. The amount of the solvent is preferably sufficient to dissolve the catalyst.
Organopolysiloxane E
In present disclosure, the organopolysiloxane E comprises at least one siloxy unit T of formula LSiO3/2 and/or at least one siloxy unit Q of formula SiO4/2, wherein L denotes OH or organic group.
For example, L may denote OH, C1-20 alkoxy, C1-20 alkyl, C2-20 alkenyl, C6-20 aryl, each of the C1- 20 alkoxy, C1-20 alkyl, C2-20 alkenyl and C6-20 aryl is optionally substituted with at least one group selected from OH, C1-6 alkyl, C6-C10 aryl, epoxy group, and acrylate group.
For example, L may denote OH, C1-12 alkoxy, C1-12 alkyl, C2-12 alkenyl, C6-10 aryl, the C1-12 alkyl is optionally substituted with at least one group selected from epoxy group, and acrylate group.
For example, L may denote OH, methoxy, ethoxy, methyl, ethyl, vinyl, epoxy group substituted C1-6 alkyl, or acrylate group substituted C1-6 alkyl.
For example, L may denote methyl or vinyl.
Wherein L in each siloxy unit T may be identical to or different from each other when more than one siloxy unit T are present.
In a preferred embodiment, the organopolysiloxane E may comprise or basically consisting of at least one organopolysiloxane resin comprising at least one organopolysiloxane resin E’ , at least one organopolysiloxane resin E”, or a combination thereof.
Thus, according to preferred embodiments, the organopolysiloxane resin may comprise or basically consisting of an organopolysiloxane resin E’ selected from:
- organopolysiloxane resin of formula MTViQ, which is basically consisted of the following units:
(a) trivalent siloxy unit TVi of formula L’SiO3/2;
(b) monovalent siloxy unit M of formula L”3SiO1/2; and
(c) tetravalent siloxy unit Q of formula SiO4/2;
- organopolysiloxane resin of formula MDViQ, which is basically consisted of the following units:
(a) divalent siloxy unit DVi of formula L”L’SiO2/2;
(b) monovalent siloxy unit M of formula L”3SiO1/2; and
(c) tetravalent siloxy unit Q of formula SiO4/2;
- organopolysiloxane resin of formula MDDViQ, which is basically consisted of the following units:
(a) divalent siloxy unit DVi of formula L”L’SiO2/2;
(b) divalent siloxy unit D of formula L”2SiO1/2;
(c) monovalent siloxy unit M of formula L”3SiO1/2; and
(d) tetravalent siloxy unit Q of formula SiO4/2;
- organopolysiloxane resin of formula MViQ, which is basically consisted of the following units:
(a) monovalent siloxy unit MVi of formula L’L”2SiO1/2; and
(b) tetravalent siloxy unit Q of formula SiO4/2; and
- organopolysiloxane resin of formula MViTViQ, which is basically consisted of the following units:
(a) monovalent siloxy unit MVi of formula L’L”2SiO1/2;
(b) trivalent siloxy unit TVi of formula L’SiO3/2; and
(c) tetravalent siloxy unit Q of formula SiO4/2;
in which
L” denotes OH or organic group.
For example, L” may denote OH, C1-20 alkoxy, C1-20 alkyl, C6-20 aryl, each of the C1-20 alkoxy, C1- 20 alkyl and C6-20 aryl is optionally substituted with at least one group selected from OH, C1-6 alkyl, C6-C10 aryl, epoxy group, and acrylate group.
For example, L” may denote OH, C1-12 alkoxy, C1-12 alkyl, C6-10 aryl, the C1-12 alkyl is optionally substituted with at least one group selected from epoxy group, and acrylate group.
For example, L” may denote OH, methoxy, ethoxy, methyl, ethyl, epoxy group substituted C1-6 alkyl, or acrylate group substituted C1-6 alkyl.
For example, L” may denote methyl.
Wherein L” may be identical to or different from each other, either in each siloxy unit as mentioned above or in more than one siloxy unit as mentioned above.
L’ represents alkenyl, preferably alkenyl with 2 to 12, more preferably 2 to 6 carbon atoms, in particular preferably vinyl or allyl, most preferably vinyl.
In further preferable embodiment, the organopolysiloxane resin E’ may be the organopolysiloxane resin of formula MDViQ, which is basically consisted of the following units:
(a) divalent siloxy unit DVi of formula L”L’SiO2/2;
(b) monovalent siloxy unit M of formula L”3SiO1/2; and
(c) tetravalent siloxy unit Q of formula SiO4/2;
wherein L” and L’ are defined as above.
Optionally, in the organopolysiloxane resin of formula MDViQ, the ratio of (the monovalent siloxy unit M+ the divalent siloxane unit DVi) to the tetravalent siloxy unit Q is from 0.8 to 1.6. Optionally, the ratio of (the monovalent siloxy unit M + the trivalent siloxy unit TVi) to the tetravalent siloxy unit Q is from 0.6 to 1.2, and the ratio of the trivalent siloxy unit TVi to the tetravalent siloxy unit Q is from 0.6 to 1.
In as yet further preferable embodiment, the organopolysiloxane resin E’ may be the organopolysiloxane resin of formula MMViQ, which is basically consisted of the following units:
(a) monovalent siloxy unit M of formula L”3SiO1/2;
(b) monovalent siloxy unit MVi of formula L’L”2SiO1/2; and
(c) tetravalent siloxy unit Q of formula SiO4/2;
wherein L” and L’ are defined as above.
Advantageously, the organopolysiloxane resin E’ has a weight-average molecular weight in range of 200-50,000 g/mol, preferably 500-30,000 g/mol, as measured by gel permeation chromatography and calculated using polystyrene as standard.
Alternatively or in addition to, the organopolysiloxane resin may comprise or basically consisting of at least one organopolysiloxane resin E”, with the proviso that siloxy unit T of formula LSiO3/2 are present within the formula with L defined as above.
In a preferred embodiment, the organopolysiloxane resin E” may be spherical particles with a particle size D50 from 0.2 to 60 μm, preferably from 0.5 to 40 μm, more preferably from 0.8 to 30 μm. Particle Size Distribution D50 is also known as the median diameter or the medium value of the particle size distribution, it is the value of the particle diameter at 50%in the cumulative distribution. It is one of important and well-known parameters characterizing particle size. The size distribution and volume mean diameter for a particle size distribution may be calculated using a laser light scattering PSD system such as those commercially available from Malvern.
By way of example, polysilsesquioxane is a preferred organopolysiloxane resin E”. By polysilsesquioxane, it means an organosilicon compound with the chemical formula [RSiO3/2] n (R = H, OH, alkyl such as methyl, ethyl, propyl etc.; alkenyl, aryl or alkoxyl) . Polysilsesquioxanes are colorless solids that adopt cage-like or ladder-like structure. For example, the polysilsesquioxane may be MIRASIL MICROPEARL 40, and the like.
In the curable silicone composition according to present invention, the organopolysiloxane E may be comprised in an amount of from 0.5wt%to 70wt%, preferably from 3wt%to 50wt%, more preferably from 10wt%to 40wt%, based on the total weight of the curable silicone composition.
In accordance with present invention, the organopolysiloxane E may comprise or basically comprise the organopolysiloxane resin E’ in an amount of from 0wt%to 50wt% (not including 0wt%, ) for example from 0.1wt%to 50wt%, wherein lower limit may be 0.1wt%, 1wt%, 2wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, or 45wt%or any numerical value contained therebetween, and upper limit may be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%or any numerical value contained therebetween, based on the total weight of the curable silicone composition.
Preferably, the organopolysiloxane E may comprise or basically comprise organopolysiloxane resin E’ in an amount of from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition, so that the obtained post-treated product could present glossy surface, good anti-scratch and anti-wear properties and desirable mechanical  properties. Further, the organopolysiloxane resin E’ may constitute a least 3wt%of the total weight of the curable silicone composition, in order to improve mechanical property.
In accordance with present invention, the organopolysiloxane E may comprise or basically comprise the organopolysiloxane resin E” in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, yet for example from 1wt%to 45wt%, further for example from 5wt%to 40wt%, and yet more for example from 15wt%to 30wt%, wherein the lower limit may be 0.1wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, or 45wt%or any numerical value contained therebetween, and the upper limit may be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%or any numerical value contained therebetween, based on the total weight of the curable silicone composition.
Preferably, when the organopolysiloxane E is consisted of the organopolysiloxane resin E” , the organopolysiloxane resin E” may constitute from greater than 10wt%to 45wt%, preferably from 15wt%to 40wt%, more preferably from 30wt%to 40wt%of the total weight of the curable silicone composition, so that the obtained post-treated product could exhibit excellent tactility (hand feeling) and matte surface without impairing the mechanical properties of the product.
Preferably, when the organopolysiloxane E comprises a combination of at least one organopolysiloxane resin E” and at least one organopolysiloxane resin E’ , the organopolysiloxane resin E’ may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably in an amount of from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition, and the organopolysiloxane resin E” may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably from 5wt%to 40wt%, more preferably from 10wt%to 30wt%, and even more preferably from 10wt%to 20wt%, based on the total weight of the curable silicone composition. Accordingly, the thus obtained post-treated product may possess very excellent tactility (hand feeling) , anti-wear and anti-scratch properties without impairing mechanical property thereof. Besides, both matte or glossy surface may be created by adjusting the proportions of the at least one organopolysiloxane resin E” and at least one organopolysiloxane resin E’, wherein the former  may contribute to a matte appearance with the latter may bring about a glossy appearance.
In accordance with present invention, the curable silicone composition for post-treatment may comprise a combination of at least one organopolysiloxane resin E’ and at least one filler, wherein the organopolysiloxane resin E’ may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably in an amount of from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition. With regard to the at least one filler, its detailed information would be discussed hereafter.
In accordance with present invention, the curable silicone composition for post-treatment may comprise a combination of at least one organopolysiloxane resin E and at least one filler with the organopolysiloxane resin E is consisted of the organopolysiloxane resin E”, the organopolysiloxane resin E” may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably from greater than 10wt%to 45wt%, more preferably from 15wt%to 40wt%, and even more preferably from 30wt%to 40wt%of the total weight of the curable silicone composition, so that the obtained post-treated product could display matte surface, very excellent (hand feeling) in conjunction with anti-scratch and mechanical properties, especially for superior elongation at break. With regard to the at least one filler, its detailed information would be discussed hereafter.
In accordance with present invention, the curable silicone composition for post-treatment may comprise a combination of at least one organopolysiloxane resin E’ , at least one organopolysiloxane resin E” and at least one filler, wherein the organopolysiloxane resin E’ may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, and even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition, and the organopolysiloxane resin E” may be in an amount of from 0wt%to 50wt% (not including 0wt%) , for example from 0.1wt%to 50wt%, preferably from 5wt%to 40wt%, more preferably from 10wt%to 30wt%, and even more preferably from 10wt%to 20wt%, based on the total weight of the curable silicone composition. Accordingly, the thus obtained post-treated product may have comprehensive superior effects including tactility, either matte or glossy surface, invisible surface texture, anti-wear and anti-scratch properties in addition with mechanical properties. With regard to the at least one filler, its  detailed information would be discussed hereafter.
Other optional components
In addition to the above-discussed components, the curable silicone coating composition according to the invention can optionally comprise further components so as to adjust the overall properties of the composition as desired.
In one preferable embodiment of the invention, the curable silicone composition may further comprise at least one filler D, preferably silica such as fumed or precipitated silica, polyamide particles and the mixture thereof.
In order to better compatible with the silicone component in the curable silicone composition, the surface of the precipitated or fumed silica particles may be rendered hydrophobic. Rendering the filler particles hydrophobic may be done either prior to or after dispersing the precipitated or fumed silica particles in the organopolysiloxane component. This can be effected by pre-treatment of the silica particles with the hydrophobing agents like fatty acids, reactive silanes, wax or reactive siloxanes. Examples include but are not limited to stearic acid, dimethyldichloro silane, trimethylchloro silane, hexamethyldisilazane, tetramethyldivinyldisilazane, hydroxyl endblocked or methyl end blocked polydimethylsiloxanes, siloxane resins or mixtures of two or more of these. The precipitated or fumed silica particles which have already been treated hydrophobic are commercially available in the market. Most preferred hydrophobing agent is hexamethyldisilazane or polyethene wax.
It is recommended that the specific surface area of the precipitated or fumed silica is from 50-400 m2/g, preferably from 100-300 m2/g, as determined by a BET method.
Polyamide particles which have a spherical shape and the specific particle size D50 as given above are also preferred filler used in the silicone coating composition, providing improved multiple performance aspects of the coating composition, such as abrasion resistance, chemical resistance, gloss reduction, hardness, and also texture creation.
The examples of suitable polyamide include such as, polyamide 6, polyamide 7, polyamide 9 or polyamide 10, preferably polyamide 6. These polyamide particles have low density which  is for example around 1.15g/cm3 and can be dispersed stably and homogenously in the coating composition.
Preferably, the filler is comprised in an amount of from 0wt%to 30wt%, preferably from 0.1wt%to 30wt%, more preferably from 1wt%to 20wt%, even more preferably from 3wt%to 18wt%, with lower limit possibly being 0.1wt%, 1wt%, 2wt%, 3wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%or any numerical value contained therebetween, and upper limit possibly being 5wt%, 10wt%, 15wt%, 20wt%, 25wt%or any numerical value contained therebetween, based on the total weight of the curable silicone composition.
Another example of such additional components is an adhesive promotor, preferably in an amount of from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.5wt%to 5wt%, based on the total weight of the curable silicone composition. In one embodiment of the disclosure, the adhesive promoter may be one or more selected from epoxy silane, alkoxy silane, acyloxy silane, aryloxy silane or oligomers thereof. They include, but are not limited to, 3-glycidoxypropyl trimethoxy silane, octyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, gamma-methacryloxy-propyltrimethoxysilane, beta- (3, 4-epoxycyclohexyl) -ethyltrimethoxysilane beta- (3, 4-epoxycyclohexyl) -ethyltriethoxysilane and bis (trimethoxysilyl propyl) fumarate, alkoxy or aryloxy silicones such as trimethoxysilyl functional groups modified silicones. Furthermore, they also include silanols, oligosiloxanes containing one or more alkoxy silyl functional group, polysiloxanes containing alkoxysilyl functional group, one or more oligomeric siloxanes containing hydroxyl functional groups, polysiloxanes containing one or more aryloxy silyl functional group, cyclosiloxanes containing one or more alkoxy silyl functional group, cyclosiloxanes containing one or more hydroxyl groups, tetra-alkoxy silanes, vinyltrimethoxysilane, and mixtures thereof, and combinations thereof. In particular, the adhesive promoter may be vinyltrimethoxysilane, epoxy-containing Polydimethylsiloxane, triallyl isocyanurate, or a combination thereof.
However, the amount of the adhesive promoter in the silicone coating composition has to be controlled within the scope of 0 to 5 parts, preferably 0 to 3 parts, most preferably 0 parts by total weight of whole composition. With more adhesive promoter, the overall properties of the cured silicone coating composition would be notably deteriorated and the preparation for the silicone coating composition would also be adversely affected.
Examples of the component that may be additionally contained in the composition include pigment, colorant or other fillers like calcium carbonate, quartz, wollastonite, cerium oxides, Al (OH) 3, Fe2O3, Al2O3, mica, talc, MgO, Mg (OH) 3, TiO2. But these fillers are preferably used in an amount of less than 30 %by total weight of whole composition, preferably less than 10 %by weight or more preferably less than 5%or most preferably 0%, since high amount of these fillers will not contribute to any further improvement of the hand feeling and mechanical properties or even make them worse.
Another additive that may be added into the silicone coating composition is the crosslinking inhibitor which are conventionally employed in polyaddition crosslinking reactions in the silicone field. They may especially be chosen from the following compounds: organopolysiloxanes substituted by at least one alkenyl which may optionally be present in cyclic form, with tetramethylvinyltetrasiloxane being particularly preferred; organic phosphines and phosphites; unsaturated amides; alkylated maleates; and acetylenic alcohols. In particular, the crosslinking inhibitor may be 2, 4, 6, 8-Tetramethyl-2, 4, 6, 8-tetravinylcyclotetrasiloxane, ethynylcyclohexanol, 2, 4, 7, 9-Tetramethyl-5-decyne-4, 7-diol, or a combination thereof.
As acetylenic alcohols, they are also preferred thermal blockers for the hydrosilylation reaction. Examples of acetylenic alcohols include especially 1-ethynyl-1-cyclohexanol, 3-methyl-1-dodecyn-3-ol, 3, 7, 11-trimethyl-1-dodecyn-3-ol, 1, 1-diphenyl-2-propyn-1-ol, 3-ethyl-6-ethyl-1-nonyn-3-ol, 2-methyl-3-butyn-2-ol, 3-methyl-1-penta-decyn-3-ol, diallyl maleate or derivatives of diallyl maleate or mixture thereof.
Advantageously, the amount of the crosslinking inhibitor in the curable silicone composition is in the range from 0wt%to 10wt%, preferably from 0.01 wt%to 8 wt%, more preferably from 0.05wt%to 4wt%, based on the total weight of the curable silicone composition.
The use of the inhibitor is effective to avoid the premature curing of the silicone composition on the tip of the nozzle and subsequent disfiguration of the printed layer.
The curable silicone composition of the present invention can further comprise one or more additives selected from antistatic agent, radiation shielding agent, free radical inhibitor,  adhesive modifier, flame retardant additive, surfactant, storage stability modifier, ozone degradation inhibitor, light stabilizer, viscosity builder, plasticizer, thixotropic agent, antioxidant and heat stabilizer. In the meantime, other polyorganosiloxanes, siloxane resins, polyorganosilsesquioxanes and silicon rubber powders can also be used.
In one preferred embodiment, the building material of an object, preferably a 3D printed object or the material from which the surface of an object, preferably a 3D printed object is made may be addition type silicone composition, comprising:
(A) at least one organopolysiloxane compound A comprising, per molecule at least two alkenyl radicals bonded to silicon atoms,
(B) at least one organohydrogenopolysiloxane compound B comprising, per molecule, at least two hydrogen atoms bonded to an identical or different silicon atom, and
(C) at least one catalyst C capable of catalyzing or promoting the hydrosilylation reaction between component (A) and component (B) , and
(E) optional organopolysiloxane E as mentioned below.
Therefore, the description given for the curable silicone composition for post treatment and individual components contained therein as stated above may apply also for the building material of 3D printed object or the material from which the surface of the 3D printed object is made.
Preferably, the building material or outermost material for an object, preferably a 3D printed object may also possess the SiH/Vinyl from 0.5 to 10 mol/mol, preferably from 0.6 to 5 mol/mol, more preferably from 0.8 to 4 mol/mol, from 1.2 to 4 mol/mol or from 1.6 to 4 mol/mol.
As stated above, although the inventive curable silicone composition for post treatment may have varied compositions, it is essential for such composition to comprise at least one organopolysiloxane E comprising at least one siloxy units T of formula LSiO3/2 and/or at least one Q of formula SiO4/2 with L defined as above, in particular MDViQ and/or MMViQ.
In a preferred embodiment, the curable silicone composition for post-treating a surface of an object, preferably a 3D printed object, comprising:
(A) from 10wt%to 90wt%, preferably from 20wt%to 80wt%, more preferably from 30wt% to 70wt%of at least one organopolysiloxane compound A comprising, per molecule at least two alkenyl radicals bonded to silicon atoms,
(B) from 0.1wt%to 20wt%, preferably from 1wt%to 15wt%, more preferably from 1wt%to 8wt%of at least one organohydrogenopolysiloxane compound B comprising, per molecule, at least two hydrogen atoms bonded to an identical or different silicon atom;
(C) from 10 to 500 ppm, preferably from 20 to 400ppm, more preferably from 50 to 200 ppm of at least one catalyst C capable of catalyzing the hydrosilylation reaction between component (A) and component (B) ;
(D) from 0wt%to 30wt%, preferably from 1wt%to 20wt%, more preferably from 3wt%to 18wt%of at least one filler D;
(E) from 0.5wt%to 70wt%, preferably from 3wt%to 50wt%, more preferably from 10wt%to 40wt%of the at least one organopolysiloxane E;
(F) from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.5wt%to 5wt%of at least one adhesive promoter F;
(G) from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.05wt%to 4wt%of at least one crosslinking inhibitor G;
wherein the wt%is based on the total weight of the curable silicone composition.
In a further embodiment, the curable silicone composition may further comprise a solvent. For example, the solvent is selected from:
(a) non-reactive polyorganosiloxanes, such as isodecamethylcyclopentasiloxane, octamethylcyclotetrasiloxane or a combination thereof;
(b) other organic solvents such as DMF, chlorobenzene, xylene, toluene, acetonitrile, ethanol, THF, chloroform, ethyl acetate, cyclohexane, butanone, acetone, petroleum ether, or a combination of at least two of them; or
(c) a combination of (a) and (b) .
In a still further embodiment, the amount of solvent used may be selected through conventional means or depending on particular application. For example, the solvent is comprised in an amount of from 0.99wt%to 99wt%, preferably from 16.7wt%to 90.9wt%, more preferably from 28.6wt%to 83.3wt%, the wt%is based on the total weight of the curable silicone composition.
In one embodiment, the inventive curable silicone composition for post-treatment is comprised of the components (A) to (G) and solvent as indicated above, wherein the total amount for components (A) to (G) and solvent is equivalent to 100wt%.
In a further advantageous embodiment, there needs less than 30 wt%, 1 wt%or 0.2 wt%or even no organic solvent in the inventive post treatment silicone composition. The omission of the organic solvent may make the post treatment silicone composition and thus the treated surface of the printed article more environmental-friendly and less vulnerable to the bacteria. Therefore, the inventive post treatment silicone composition or the article treated thereby is suitable for the medical application such as an additive manufactured medical device or prosthetic appliance.
In a preferred embodiment, the curable silicone composition used for the post treatment may be identical to or different from the material from which the surface of the object is made. Preferably, both the curable silicone compositions and the material from which the surface of the object is made may be addition type silicone composition.
In another aspect, the present disclosure refers to a 3D printing process comprising the following steps:
i’) fabricating an object by a 3D printing method, wherein the object has a surface made of polymeric material, preferably the object is made of polymeric material, more preferably made of silicone material,
ii’) post-treating the surface of the object by the post-treatment method as mentioned above.
Preferably, the entire 3D printed object is made of a polymeric material.
Applying the curable silicone composition for post treatment to the surface of an object, preferably a 3D printed object may be carried out in varied ways as long as a coating or a layer may be formed covering the exterior surface to be treated. In one preferable embodiment, the object, preferably the 3D printed object obtained from 3D printing process may be dipped into a bath of the curable silicone composition for post-treatment. The dip coating may be carried out at varied temperatures, in particular at the room temperature. Finally, the dip coated object is taken out from the bath and allowed to be cured.
The coated curable silicone composition may be then cured at room temperature or under heat or UV radiation. As for the curing at room temperature or under heat, the employed temperature may be from room temperature (about 23℃) up to for example 150℃. As for  the curing under UV radiation, any UV light source may be employed such as a LED lamp or mercury lamp as long as it can provide the sufficient energy to cure the curable silicone composition. In one embodiment, the UV curing may be conducted for 0.001 s to 30 min, in particular for 0.1 s to 2min.
With the inventive method, no mechanical surface treatments like blasting or polishing for making the surface even or removing the surface texture may be needed in the 3D printing or additive manufacturing process, in particular between steps i’ ) and ii’ ) or after step ii’ ) . The non-limiting examples which follow further illustrate the invention in more details.
EXAMPLES
Raw materials
Table 1. Raw materials used in present invention


Descriptions of the measurements
Viscosity: According to ASTM D445, the viscosity of the curable silicon composition is tested at 23℃, the details of testing conditions can be seen in Tables 3, in which, for example, the expression (5#, 10 rpm) means that the viscosity is measured at 10 rpm by using spindle number 5, and so on.
Hardness: The hardness of the cured samples obtained by curing the curable silicone composition of Examples 1-9 at 150℃ for 1 h was measured at 23℃ according to ASTM D2240.
Tensile strength and Elongation at break: Tensile strength and elongation at break of cured samples obtained by curing the curable silicone composition of Examples 1-9 at 150℃ for 1 h were measured at 23℃ according to ASTM D412.
Tear strength: Tear strength of cured samples obtained by curing the curable silicone composition of Examples 1-9 at 150℃ for 1 h was measured at 23℃ according to ASTM D642.
Anti-wear property: Anti-wear property of 3D printed object after post-treatment with the curable silicone composition of Examples 1-1 to Example 9-1 was evaluated by a wear tester using Taber 5135 according to ASTM D4060-19 with Test mode of 2000 cycles.
Scratch resistance: Scratch resistance of 3D printed object after post-treatment with the curable silicone composition of Examples 1-1 to Examples 9-1 was expressed by the proportion of surface area worn out by scratch to the original surface area.
Surface condition: Conducting visual assessment on the surface condition of the 3D printed object after post-treatment with the curable silicone composition of Examples 1-1 to Example 9-1. Wherein glossiness refers to the state of matte(哑光) or gloss(亮光) . The state of surface texture, transparency, and the degree of slippery(爽滑) in hand feeling are graded with asterisks.
Preparation of a 3D printing part to be post treated
3D printing process was carried out by using a Sandraw S300 extrusion 3D printer according to the following procedure:
I. loading the building material as shown in Table 2 into an extruder;
II. level adjusting the printing platform and setting the following printing parameters:
extruder head diameter: 0.4mm
filling rate: 95%
extrusion rate: 85%
printing speed: 20mm/s
III. printing a 3D ring with building materials via layer-by-layer deposition.
Two 3D printed rings with outer diameter of 108.2mm, inner diameter of 6.5mm andthickness of 1mm were obtained, which has obvious surface texture resulted from layer-by-layer deposition of the building material.
After the surface of the 3D printed rings was completely cleaned, it was placed into an ovenat 150℃ for 0.5h until completely cured.
Table 2. Building materials for the 3D printed rings

Preparation of post treatment silicone composition
Example 1 was prepared as follows: 8.39 parts of A-1, 27.62 parts of A-3, 13.59 parts of A-4, 4.8 parts of A-5 were mixed with 6.36 parts of B-1 under agitation. Then 3.43 parts of D-1 and 8.72 parts of E-1 and 26.68 parts of E-3 were added into the above mixture, followed by addition of 0.4 parts of G-2 with through stirring. Finally, 0.015 parts of catalyst C-1 was added to obtain Example 1.
Example 2-9 was likewise prepared according to Example 1 except varying the amounts of the components as shown in Tables 3.
Comparative Example was a reference example wherein the 3D printed object was not post treated by the inventive curable silicone composition.

Coating and curing of the curable silicone composition for post-treatment
To 50g of curable silicone composition obtained in accordance with Example 1 adding 25g of solvent H1 with stirring until homogeneous mixture was obtained, and then removing bubbles by vacuum to achieve a bath of curable composition for post-treatment.
The 3D printed sample was dipped into the above bath for post-treatment and then was left to stay at room temperature for 5 minutes in a dust-free environment until a uniform coating layer is obtained without any droplet dripping from the article. Then, the coated 3D printed sample was placed in an oven at 150℃ and subjected to curing for 30 minutes before taken out for cooling.
The surface condition of the 3D printed sample after post-treatment with inventive curable silicone composition in accordance with Examples 1-1 to Example 9-1 was measured and the results were shown in Table 5.
The anti-wear and anti-scratch properties of the 3D printed sample after post-treatment with inventive curable silicone composition in accordance with Examples 1-1 to Examples 9-1 were measured and the results were shown in Table 6.
The mechanical properties of the cured silicone composition in accordance with Examples 1 to Examples 9 were measured and the results were shown in Table 7.
The Comparative Example has obtained 3D printed sample with obvious visible surface texture, poor transparency and rough surface in tactility.
As shown from the above, the 3D printed object after post-treatment with the inventive curable silicone composition comprising the essential component E has exhibited a variety of good performances. The thus obtained post-treated object was slippery in hand feeling with invisible surface texture while maintaining the desired mechanical properties of the coating. What’s more, thus obtained post-treated object was more resistant to wear and scratch. Besides, both the surface state of matte and glossy may be achieved which are suitable for varied intended application.
As for the inventive curable silicone composition comprising organopolysiloxane resin E’, it enables the thus obtained object significantly increased wear resistance and scratch resistance which is of great beneficial when in use.
As for the inventive curable silicone composition comprising organopolysiloxane resin E” (e.g. Examples 4) , very excellent tactility (hand feeling) is achieved together with surface state of matte without impairing the mechanical property.
As for the inventive curable silicone composition comprising organopolysiloxane resin E” and organopolysiloxane resin E’ (e.g. Example 6) , very excellent tactility (hand feeling) is observed together with excellent anti-wear and anti-scratch properties and desirable mechanical properties. Meanwhile, it is possible to display either matte or glossy surface by adjusting the proportions of organopolysiloxane resin E” and organopolysiloxane resin E’ , in order to tailor to particular needs.
As for the inventive curable silicone composition comprising organopolysiloxane resin E” and filler (e.g. Example 5) , very excellent tactility (hand feeling) , good anti-scratch property and mechanical property (e.g. superior elongation at break) are accomplished while presenting matte surface.
As for the inventive curable silicone composition comprising organopolysiloxane resin E” , organopolysiloxane resin E’ and filler (e.g. Example 1) , comprehensive superior effects would be achieved including tactility, either matte or glossy surface, invisible surface texture, anti-wear and anti-scratch properties in addition with mechanical properties.
As shown from Figure 2, more transparent, glossy post-treated 3D printed object having a  significant reduced surface texture has been obtained by inventive post-treatment method. Also, the thus obtained post-treated 3D printed object is slippery in hand feeling and more resistant to wear and scratch.

Claims (29)

  1. A method for post-treating a surface of an object, preferably a 3D printed object, comprising
    i) applying a coating of a curable silicone composition to at least part of the surface of the object; and
    ii) curing the coating;
    wherein the curable silicone composition comprises at least one organopolysiloxane E comprising at least one siloxy unit T of formula LSiO3/2 and/or at least one siloxy unit Q of formula SiO4/2, with L denotes OH or organic group.
  2. The method according to claim 1, wherein the organopolysiloxane E is comprised in an amount of from 0.5wt%to 70wt%, preferably from 3wt%to 50wt%, more preferably from 10wt%to 40wt%, based on the total weight of the curable silicone composition.
  3. The method according to claim 1 or 2, wherein the organopolysiloxane E comprises at least one organopolysiloxane resin.
  4. The method according to claim 3, wherein the organopolysiloxane resin comprises at least one organopolysiloxane resin E’, or at least one organopolysiloxane resin E”, or a combination thereof, wherein the organopolysiloxane resin E” comprises polysilsesquioxane, and the organopolysiloxane resin E’ comprises at least one selected from MTViQ, MDViQ, MDDViQ, MViQ, MViTViQ, MMViQ, preferably the organopolysiloxane resin E’ comprises MDViQ, MMViQ, or a combination thereof.
  5. The method according to claim 4, wherein the at least one organopolysiloxane resin comprises at least one organopolysiloxane resin E”, preferably in an amount of from 0wt%to 50wt% (not including 0wt%) , based on the total weight of the curable silicone composition; preferably the at least one organopolysiloxane resin is consisted of at least one organopolysiloxane resin E”, preferably in an amount of from greater than 10wt%to 45wt%, more preferably from 15wt%to 40wt%, and even more preferably from 30wt%to 40wt%, based on the total weight of the curable silicone composition.
  6. The method according to claim 4, wherein the curable silicone composition comprises a combination of at least one organopolysiloxane resin E’ and at least organopolysiloxane resin E”.
  7. The method according to claim 6, wherein the organopolysiloxane resin E” is comprised in an amount of from 0wt%to 50wt% (not including 0wt%) , preferably from 5wt%to 40wt%, more preferably from 10wt%to 30wt%, and even more preferably from 10wt%to 20wt%, based on the total weight of the curable silicone composition, and the organopolysiloxane resin E’ is comprised in an amount of from 0wt%to 50wt% (not including 0wt%) , preferably from 3wt%to 40wt%, more preferably from 10wt%to 40wt%, and even more preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition.
  8. The method according to claim 4, wherein the curable silicone composition comprises at least one organopolysiloxane resin E’, preferably in an amount of from 0wt%to 50wt% (not including 0wt%) , more preferably from 0.1wt%to 50wt%, even more preferably from 3wt%to 40wt%, yet more preferably from 10wt%to 40wt%, and most preferably from 15wt%to 30wt%, based on the total weight of the curable silicone composition.
  9. The method according to any of the preceding claims, wherein the curable silicone composition further comprises at least one filler, preferably silica such as fumed or precipitated silica, polyamide particles, or a mixture thereof.
  10. The method according to claim 9, wherein the filler is comprised in an amount of from 0wt%to 30wt% (not including 0wt%) , preferably from 0.1wt%to 30wt%, more preferably from 1wt%to 20wt%, even more preferably from 3wt%to 18wt%, based on the total weight of the curable silicone composition.
  11. The method according to any of the preceding claims, wherein the curable silicone composition further comprises at least one adhesive promoter, preferably in an amount of from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.5wt%to 5wt%, based on the total weight of the curable silicone composition.
  12. The method according to any of the preceding claims, wherein the surface to be post  treated is made of polymeric material, preferably silicone material, more preferably addition type silicone material.
  13. The method according to any of the preceding claims, wherein the curable silicone composition comprises:
    (A) at least one organopolysiloxane compound A comprising, per molecule at least two alkenyl radicals bonded to silicon atoms, optionally the organopolysiloxane compound A is of a linear, branched, or cyclic structure;
    (B) at least one organohydrogenopolysiloxane compound B comprising, per molecule, at least two hydrogen atoms bonded to an identical or different silicon atom;
    (C) at least one catalyst C capable of catalyzing the hydrosilylation reaction between component (A) and component (B) ; and
    (E) the at least one organopolysiloxane E comprising at least one siloxy unit T of formula LSiO3/2 and/or at least one siloxy unit Q of formula SiO4/2.
  14. The method according to any of the preceding claims, wherein the curable silicone composition further comprises a solvent, preferably the solvent is selected from:
    (a) non-reactive polyorganosiloxanes, such as isodecamethylcyclopentasiloxane, octamethylcyclotetrasiloxane or a combination thereof;
    (b) other organic solvents such as DMF, chlorobenzene, xylene, toluene, acetonitrile, ethanol, THF, chloroform, ethyl acetate, cyclohexane, butanone, acetone, petroleum ether, or a combination of at least two of them; or
    (c) a combination of (a) and (b) .
  15. The method according to claim 14, wherein the solvent is comprised in an amount of from 0.99wt%to 99wt%, preferably from 16.7wt%to 90.9wt%, more preferably from 28.6wt%to 83.3wt%, based on the total weight of the curable silicone composition.
  16. The method according to any of preceding claims, wherein the curable silicone composition comprises:
    (A) from 10wt%to 90wt%, preferably from 20wt%to 80wt%, more preferably from 30wt%to 70wt%of at least one organopolysiloxane compound A comprising, per molecule at least two alkenyl radicals bonded to silicon atoms, optionally the organopolysiloxane compound A is of a linear, branched, or cyclic structure;
    (B) from 0.1wt%to 20wt%, preferably from 1wt%to 15wt%, more preferably from 1wt%to 8wt%of at least one organohydrogenopolysiloxane compound B comprising, per molecule, at least two hydrogen atoms bonded to an identical or different silicon atom;
    (C) from 10 to 500 ppm, preferably from 20 to 400ppm, more preferably from 50 to 200 ppm of at least one catalyst C capable of catalyzing the hydrosilylation reaction between component (A) and component (B) ;
    (D) from 0wt%to 30wt%, preferably from 1wt%to 20wt%, more preferably from 3wt%to 18wt%of at least one filler D;
    (E) from 0.5wt%to 70wt%, preferably from 3wt%to 50wt%, more preferably from 10wt%to 40wt%of the at least one organopolysiloxane E;
    (F) from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.5wt%to 5wt%of at least one adhesive promoter F; and
    (G) from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.05wt%to 4wt%of at least one crosslinking inhibitor G;
    wherein the wt%is based on the total weight of the curable silicone composition.
  17. The method according to any of the preceding claims, wherein no mechanical surface treatments like blasting or polishing are carried out before the step i) or after the step ii) .
  18. The method according to any of the preceding claims, wherein in step i) , the coating of the curable silicone composition is applied to at least part of the surface of the object by dipping at least part of the surface of the object into a bath of the curable silicone composition.
  19. The method according to any of the preceding claims, wherein in step ii) , the coating is cured at room temperature or under heat or UV irradiation, in particular at temperature from 23℃ to 180℃.
  20. The method according to any of the preceding claims, wherein the curable silicone composition has a molar ratio of SiH bond to vinyl group of from 0.5 to 10, preferably from 0.6 to 5, more preferably from 0.8 to 4, from 1.2 to 4 or from 1.6 to 4.
  21. A curable silicone composition for post-treating a surface of an object, preferably a 3D printed object, comprising:
    (A) from 10wt%to 90wt%, preferably from 20wt%to 80wt%, more preferably from 30wt% to 70wt%of at least one organopolysiloxane compound A comprising, per molecule at least two alkenyl radicals bonded to silicon atoms, optionally the organopolysiloxane compound A is of a linear, branched, or cyclic structure;
    (B) from 0.1wt%to 20wt%, preferably from 1wt%to 15wt%, more preferably from 1wt%to 8wt%of at least one organohydrogenopolysiloxane compound B comprising, per molecule, at least two hydrogen atoms bonded to an identical or different silicon atom;
    (C) from 10 to 500 ppm, preferably from 20 to 400ppm, more preferably from 50 to 200 ppm of at least one catalyst C capable of catalyzing the hydrosilylation reaction between component (A) and component (B) ;
    (D) from 0wt%to 30wt%, preferably from 1wt%to 20wt%, more preferably from 3wt%to 18wt%of at least one filler D;
    (E) from 0.5wt%to 70wt%, preferably from 3wt%to 50wt%, more preferably from 10wt%to 40wt%of the at least one organopolysiloxane E;
    (F) from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.5wt%to 5wt%of at least one adhesive promoter F; and
    (G) from 0wt%to 10wt%, preferably from 0.01wt%to 8wt%, more preferably from 0.05wt%to 4wt%of at least one crosslinking inhibitor G;
    wherein the wt%is based on the total weight of the curable silicone composition.
  22. Use of the curable silicone composition as defined in any one of claims 1 to 20 or the curable silicone composition according to claim 21 for imparting at least one of glossy or matte surface, improved hand feeling, improved anti-wear and anti-scratch properties to an object, preferably a 3D printed object, more preferably a 3D printed silicone object.
  23. A post-treatment agent, comprising or basically consisting of the curable silicone composition as defined in any one of claims 1 to 20 or the curable silicone composition according to claim 21.
  24. A 3D printing process comprising the following steps:
    i’) fabricating an object by 3D printing, wherein the object has a surface made of polymeric material, preferably the object is made of polymeric material, more preferably made of silicone material, and
    ii’) post-treating the surface of the object by the method as defined in any one of claims 1-20.
  25. The process according to claim 24, wherein no mechanical surface treatments like blasting or polishing are carried out between steps i’) and ii’) or after step ii’) .
  26. A medical device such as a prosthesis, comprising a surface treated by the method as defined in any one of claims 1-20, preferably the medical device is an additive manufactured medical device.
  27. Consumer products such as clothes, shoes, hats, bags and luggage, or ornaments, comprising a surface treated by the method as defined in any one of claims 1-20, preferably the consumer products are made from an additive manufactured process.
  28. Human-mimic products such as robots, dolls, or mannequins having skin-like appearance, comprising a surface treated by the method as defined in any one of claims 1-20, preferably the human-mimic products are made from an additive manufactured process.
  29. An article made of silicone, plastic, metal or ceramic, comprising a surface treated by the method as defined in any one of claims 1-20, preferably the article is an additive manufactured article.
PCT/CN2023/121175 2022-09-27 2023-09-25 Method for post-treating an object WO2024067506A1 (en)

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US3159602A (en) 1962-06-07 1964-12-01 Olin Mathieson Preparation of polymeric phosphates
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