3D printing resin composition for jewelry investment casting and preparation method and application thereof

Abstract

The present invention provides a 3D printing resin composition for jewelry investment casting and a preparation method and application thereof, which relates to the technical field of 3D printing materials and comprises the following components: a monofunctional acrylate resin monomer, an oxidized grafted modified petroleum wax and an ethylene-vinyl acetate copolymer, and optionally a photoinitiator, a rheology modifier and an ultraviolet absorber; wherein the oxidized grafted modified petroleum wax is prepared by introducing a polar group into the oxidized petroleum wax, and the 3D printing resin composition for jewelry investment casting provided by the present invention has improved mechanical strength and surface accuracy, and solves the technical problems of insufficient mechanical properties and poor surface finish of a traditional pure wax system.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing materials, and in particular to a 3D printing resin composition for jewelry investment casting, and a preparation method and application thereof. Background Art

[0002] Material jet printing (MJP) technology is widely used in the field of jewelry wax model manufacturing due to its high precision and surface quality advantages. At present, the MJP 3D printing materials used for jewelry casting are mainly pure wax materials. Although this type of material can meet the basic requirements of lost wax casting, there are the following technical problems in practical applications:

[0003] 1. Insufficient mechanical properties: Existing pure wax materials are prone to deformation or cracking during printing and post-processing, especially when making thin-walled and detailed structures: the support structure removal process is prone to damage the model, the wax mold is prone to breakage during transportation and storage, and the success rate of complex structures and suspended structures is low.

[0004] 2. Limited molding accuracy: Due to the characteristics of pure wax materials, the following problems exist during the printing process: low interlayer bonding strength affects vertical accuracy; rapid cooling and inability to level, resulting in obvious rings and steps, affecting surface accuracy, making the subsequent polishing process of jewelry casting complicated, greatly affecting production efficiency.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] One of the purposes of the present invention is to provide a 3D printing resin composition for jewelry investment casting to at least solve one of the technical problems existing in the prior art. The 3D printing resin composition for jewelry investment casting provided by the present invention improves mechanical strength and surface accuracy, and solves the technical problems of insufficient mechanical properties and poor surface finish of the traditional pure wax system.

[0007] A second object of the present invention is to provide a method for preparing a 3D printing resin composition for jewelry investment casting.

[0008] The third object of the present invention is to provide a 3D printing resin composition for jewelry investment casting or the use of the preparation method in the manufacture of jewelry investment casting.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] In a first aspect, the present invention provides a 3D printing resin composition for jewelry investment casting, comprising the following components:

[0011] Monofunctional acrylate resin monomer, oxidative graft modified petroleum wax and ethylene-vinyl acetate copolymer, and optionally a photoinitiator, a rheology regulator and an ultraviolet absorber;

[0012] The oxidized grafted modified petroleum wax is prepared by introducing polar groups into oxidized petroleum wax.

[0013] Further, the following components are included by mass percentage:

[0014] 60%-75% monofunctional acrylate resin monomer, 20%-35% oxidative grafted modified petroleum wax, 1%-5% ethylene-vinyl acetate copolymer, 0.5%-3% photoinitiator, 1%-2% rheology regulator and 0.1%-0.5% UV absorber.

[0015] Furthermore, the oxidized grafted modified petroleum wax is prepared by grafting oxidized petroleum wax with monofunctional small molecule alcohol;

[0016] and / or, the polar group comprises an ester group;

[0017] And / or, the oxidized petroleum wax includes at least one of oxidized paraffin and oxidized microcrystalline wax;

[0018] And / or, the monofunctional small molecule alcohol includes at least one of n-butanol, isobutanol, propanol and isopropanol.

[0019] Further, the monofunctional acrylate resin monomer includes at least one of a rigid monofunctional acrylate resin monomer and a flexible monofunctional acrylate resin monomer;

[0020] And / or, the rigid monofunctional acrylate resin monomer includes at least one of isobornyl acrylate, isobornyl methacrylate, dicyclopentadiene acrylate, and 4-tert-butylcyclohexyl acrylate, and the flexible monofunctional acrylate resin monomer includes at least one of isodecyl acrylate, lauryl acrylate, and lauryl methacrylate;

[0021] And / or, the rigid monofunctional acrylate resin monomer accounts for 30%-50% of the total mass of the 3D printing resin composition, and the flexible monofunctional acrylate resin monomer accounts for 25%-35% of the total mass of the 3D printing resin composition;

[0022] And / or, the melt index of the ethylene-vinyl acetate copolymer is less than 450 g / 10 min.

[0023] Furthermore, the photoinitiator includes at least one of TPO-L and TPO.

[0024] Furthermore, the rheology regulator includes at least one of polydimethylsiloxane, silicone acrylate and modified silicone polyether.

[0025] Furthermore, the ultraviolet absorber includes at least one of UV-326, Tinuvin 123 and UV-384.

[0026] In a second aspect, the present invention provides a method for preparing the 3D printing resin composition for jewelry investment casting, comprising the following steps:

[0027] The monofunctional acrylate resin monomer, oxidative graft modified petroleum wax, ethylene-vinyl acetate copolymer, photoinitiator, rheology modifier and ultraviolet absorber are mixed in a formulated amount to obtain the 3D printing resin composition for jewelry investment casting.

[0028] Furthermore, the oxidative grafted modified petroleum wax is prepared by the following preparation method:

[0029] Under the catalytic action of an acid agent, oxidized petroleum wax is mixed with a monofunctional small molecule alcohol to carry out a grafting reaction to obtain the oxidized grafted modified petroleum wax;

[0030] And / or, the mass percentage of the oxidized petroleum wax used is 78%-82%, and the mass percentage of the monofunctional small molecule alcohol used is 18%-22%;

[0031] And / or, the amount of the acid agent used is 0.09%-0.11% of the total mass of the oxidized petroleum wax and the monofunctional small molecule alcohol;

[0032] and / or, the acid agent comprises at least one of benzenesulfonic acid, p-toluenesulfonic acid, 98% concentrated sulfuric acid and phosphoric acid;

[0033] And / or, the reaction temperature of the grafting reaction is 105-120° C., and the reaction time is 1.5-2.5 h;

[0034] And / or, the mixing process includes: mixing the heated and melted oxidized grafted modified petroleum wax and ethylene-vinyl acetate copolymer at a first temperature and stirring, then adding a monofunctional acrylate resin monomer at a second temperature, then adding a rheology modifier, and then adding an ultraviolet absorber and a photoinitiator;

[0035] and / or, the first temperature is 105-110° C.;

[0036] And / or, the stirring time is 85-95 min;

[0037] And / or, the second temperature is 85-95°C.

[0038] In a third aspect, the present invention provides a 3D printing resin composition for jewelry investment casting or an application of the preparation method in manufacturing jewelry investment casting.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The 3D printing resin composition for jewelry investment casting provided by the present invention introduces oxidized grafted modified petroleum wax into the monofunctional acrylate resin. The oxidized grafted modified petroleum wax significantly enhances the compatibility with the acrylate resin monomer by introducing polar groups into the petroleum wax, thereby avoiding microscopic defects (such as surface roughness or granulation) caused by component separation during the resin curing process. This good compatibility makes the surface of the material more uniform and smooth after curing, greatly improving the mechanical properties and surface finish of the resin composition. At the same time, ethylene-vinyl acetate copolymer provides a certain degree of flexibility and enhances compatibility, improving the mechanical properties of the material. By adding oxidized grafted modified petroleum wax and ethylene-vinyl acetate copolymer to the resin system, a resin-wax mixed system is formed, which enhances compatibility and can effectively adjust the fluidity and curing behavior of the material, thereby reducing the surface fluctuation and shrinkage of the material during the printing process, thereby improving the surface accuracy of the product. DETAILED DESCRIPTION

[0041] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear, however, in the case of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-limiting.

[0042] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] The present invention provides a first aspect of a 3D printing resin composition for jewelry investment casting, comprising the following components:

[0044] Monofunctional acrylate resin monomer, oxidized grafted modified petroleum wax and ethylene-vinyl acetate copolymer, and optional photoinitiator, rheology regulator and ultraviolet absorber; wherein the oxidized grafted modified petroleum wax is prepared by introducing polar groups into oxidized petroleum wax.

[0045] The 3D printing resin composition for jewelry investment casting provided by the present invention introduces oxidized grafted modified petroleum wax into the monofunctional acrylate resin monomer. The oxidized grafted modified petroleum wax significantly enhances the compatibility with the acrylate resin monomer by introducing polar groups into the petroleum wax, thereby avoiding microscopic defects (such as surface roughness or granulation) caused by component separation during the resin curing process. This good compatibility makes the surface of the material more uniform and smooth after curing, greatly improving the mechanical properties and surface finish of the resin composition. At the same time, ethylene-vinyl acetate copolymer provides a certain degree of flexibility and enhances compatibility, improving the mechanical properties of the material. By adding oxidized grafted modified petroleum wax and ethylene-vinyl acetate copolymer to the resin system, a resin-wax mixed system is formed, which enhances compatibility and can effectively adjust the fluidity and curing behavior of the material, thereby reducing the surface fluctuation and shrinkage of the material during the printing process, thereby improving the surface accuracy of the product.

[0046] In some preferred embodiments, the following components are included by mass percentage:

[0047] 60-75% monofunctional acrylate resin monomer, 20%-35% oxidative grafted modified petroleum wax and 1%-5% ethylene-vinyl acetate copolymer, 0.5%-3% photoinitiator, 1%-2% rheology regulator and 0.1%-0.5% UV absorber.

[0048] The 3D printing resin composition for jewelry investment casting provided by the present invention is a high surface precision MJP 3D printing resin composition for jewelry precision casting, especially for wax mold making in the field of jewelry casting. Although the existing pure wax system is easy to process and demold, its mechanical strength and surface precision are relatively low, and it is difficult to meet the requirements of jewelry casting with high precision and complex details. The present invention forms a resin-wax mixed system by adding an appropriate amount of oxidized grafted modified petroleum wax and EVA (ethylene-vinyl acetate copolymer) into the resin system, thereby achieving the following technical improvements: (1) Improving the mechanical strength of the wax model: Pure wax printing materials also contain about 20-30% of resin materials. Common resin materials added to the pure wax system mainly include petroleum resin, rosin glycerol ester, terpene resin, etc. The main function of adding resin is to improve the mechanical properties of the wax material. However, since the 3D printing nozzle cannot print materials with too high viscosity, the amount of resin material added is limited, which limits the improvement of the mechanical properties of the printed wax model. In the resin-wax mixed system provided by the present invention, the resin exists in the form of a monomer, which is mainly a monofunctional acrylate resin monomer, accounting for 60%-75%. Through the photocuring of the acrylate resin during the printing process, the resin monomer is converted into a high molecular weight polymer, which enhances the internal network structure of the material, thereby improving the mechanical properties of the wax model, overcoming the problems of pure wax materials with less resin content being easy to break and having poor impact resistance under high-precision structures, making the wax model more suitable for high-precision molding of complex jewelry pieces. (2) Improving the surface accuracy of wax models: The oxidized grafted modified paraffin wax, oxidized grafted modified microcrystalline wax and EVA introduced into the composite wax have good compatibility in the resin system and can effectively adjust the fluidity and curing behavior of the material, thereby reducing the surface fluctuation and shrinkage of the material during the printing process. Through this optimized combination of resin and wax, the smoothness of the molding surface can be significantly improved while ensuring the fluidity of the material, meeting the requirements for high surface quality in the jewelry casting process. Therefore, the present invention provides a new type of resin-wax composite material, which solves the technical problems of insufficient mechanical properties and poor surface finish of the traditional pure wax system, and provides a more reliable and precise 3D printing material for the jewelry casting field.

[0049] In addition, precise control of the content of oxidized grafted petroleum wax enables the printed models to retain the wax's easy processing and good burn-off properties.

[0050] In the present invention, a large proportion of photosensitive resin (i.e., monofunctional acrylate resin monomer) is added to the composition, which can greatly reduce the solidification rate. Even after solidification, it is still in a paste state and has a strong affinity with the printing surface, so the interlayer bonding force is large.

[0051] Wherein, based on the total mass of the 3D printing resin composition for jewelry investment casting as 100%, the added amount of the monofunctional acrylate resin monomer is 60%-75%, for example, 60%, 65%, 70%, 75%, etc.;

[0052] Taking the total mass of the 3D printing resin composition for jewelry investment casting as 100%, the addition amount of the oxidized grafted modified petroleum wax is 20%-35%, for example, 20%, 25%, 30%, 35%, etc.;

[0053] Taking the total mass of the 3D printing resin composition for jewelry investment casting as 100%, the addition amount of ethylene-vinyl acetate copolymer is 1%-5%, for example, 1%, 2%, 3%, 4%, 5%, etc.;

[0054] Taking the total mass of the 3D printing resin composition for jewelry investment casting as 100%, the amount of the photoinitiator added is 0.5%-3%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc.;

[0055] Taking the total mass of the 3D printing resin composition for jewelry investment casting as 100%, the amount of the rheology modifier added is 1%-2%, for example, 1%, 1.5%, 2%, etc.;

[0056] Taking the total mass of the 3D printing resin composition for jewelry investment casting as 100%, the added amount of the ultraviolet absorber is 0.1%-0.5%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc.

[0057] In some preferred embodiments, the oxidized grafted modified petroleum wax is obtained by grafting oxidized petroleum wax with a monofunctional small molecule alcohol;

[0058] and / or, the polar group comprises an ester group;

[0059] And / or, the oxidized petroleum wax includes at least one of oxidized paraffin and oxidized microcrystalline wax;

[0060] And / or, the monofunctional small molecule alcohol includes at least one of n-butanol, isobutanol, propanol and isopropanol.

[0061] In the present invention, the oxidized grafted modified petroleum wax is mainly oxidized paraffin and oxidized microcrystalline wax with excess monofunctional small molecule alcohols such as n-butanol, isobutanol, propanol, isopropanol, etc., and ester groups are introduced through grafting reaction to enhance compatibility with acrylate resin, while reducing volume expansion and increasing surface finish; the oxidized grafted modified petroleum wax achieves the effect of significantly enhancing compatibility with monofunctional acrylate resin monomers by introducing polar groups (ester groups) into petroleum waxes such as paraffin and microcrystalline wax, wherein the oxidized paraffin is introduced with polar groups (ester groups) to obtain oxidized grafted modified paraffin, and the oxidized microcrystalline wax is introduced with polar groups (ester groups) to obtain oxidized grafted modified microcrystalline wax.

[0062] Specifically, petroleum waxes such as paraffin or microcrystalline wax can be oxidized to obtain oxidized petroleum wax. Deeply oxidized petroleum wax contains a large amount of fatty acids. Since the hydrocarbon carbon chain in the petroleum wax breaks during the oxidation process, the carbon number distribution of the generated fatty acids is very wide, ranging from water-soluble fatty acids with a few carbon numbers to oil-soluble fatty acids with dozens of carbon numbers. Small-molecule fatty acids have a strong odor and high polarity, and have poor compatibility with most acrylic resin monomers. For this reason, oxidized petroleum wax is grafted and modified. The esterification reaction of fatty acids with monofunctional short-chain alcohols such as n-butanol, isopropanol, n-hexanol, etc. is carried out under the catalysis of organic acids to convert the oxidized petroleum wax into oxidized petroleum wax fatty acid esters, thereby improving the compatibility with acrylic resins and improving the mechanical properties of acrylic resins and wax materials after curing.

[0063] In some preferred embodiments, the monofunctional acrylate resin monomer includes at least one of a rigid monofunctional acrylate resin monomer and a flexible monofunctional acrylate resin monomer, wherein the rigid monofunctional acrylate resin monomer includes at least one of IBOA (isobornyl acrylate), IBOMA (isobornyl methacrylate), DCPA (dicyclopentadiene acrylate), and TBCHA (4-tert-butylcyclohexyl acrylate), and the flexible monofunctional acrylate resin monomer includes at least one of IDA (isodecyl acrylate), LA (lauryl acrylate), and LMA (lauryl methacrylate). The rigid monofunctional acrylate resin monomer accounts for 30%-50% of the total proportion of the component formula of the composition, for example, 30%, 35%, 40%, 45%, 50%, etc., and the flexible monofunctional acrylate resin monomer accounts for 25%-35% of the total proportion of the component formula of the composition, for example, 25%, 30%, 35%, etc.

[0064] In the present invention, low-polarity monofunctional acrylate monomers are mainly used, which are compatible with oxidative graft-modified waxes and EVA.

[0065] In some preferred embodiments, the photoinitiator includes at least one of TPO-L: ethyl 2,4,6-trimethylbenzoyl)-phenylphosphinate and TPO: (2,4,6-trimethylbenzoyl) diphenylphosphine oxide.

[0066] In the present invention, a photoinitiator with good thermal stability, such as TPO-L and TPO, is mainly used, which is suitable for photocuring reaction in a high temperature environment to ensure a stable curing effect of the material.

[0067] In some preferred embodiments, the rheology modifier includes at least one of polydimethylsiloxane, silicone acrylate and modified silicone polyether.

[0068] In the present invention, silicone rheology modifiers such as polydimethylsiloxane, silicone acrylate, and modified silicone polyether are mainly used to improve the leveling and demoulding properties of the resin, thereby improving the surface finish.

[0069] In some preferred embodiments, the ultraviolet absorber includes at least one of UV-326, Tinuvin 123 and UV-384.

[0070] In the present invention, the ultraviolet absorber is used to improve the stability of the material under ultraviolet exposure conditions and prevent the resin from yellowing and deteriorating.

[0071] In the 3D printing resin composition for jewelry investment casting provided by the present invention, monofunctional acrylate resin monomers account for 60%-75% (wherein, rigid monofunctional acrylate resin monomers account for 30%-50%, and flexible monofunctional acrylate resin monomers account for 25%-35%), oxidative grafted modified paraffin wax and / or oxidative grafted modified microcrystalline wax account for 20%-35%, and EVA accounts for 1%-5%. By selecting suitable additives, such as photoinitiators, rheology regulators, etc., the performance of the resin composition can be further optimized, thereby enhancing the mechanical properties, shrinkage resistance and stability of the material on the basis of improving the surface finish.

[0072] It is further explained that the 3D printing resin composition for jewelry investment casting provided by the present invention significantly improves the surface finish of the MJP 3D printed model through the following aspects: (1) High compatibility of resin and wax: The oxidized grafted modified paraffin wax and oxidized grafted modified microcrystalline wax significantly enhance their compatibility with the acrylate resin monomer by introducing polar groups (ester groups), thereby avoiding microscopic defects (such as surface roughness or granulation) caused by component separation during the resin curing process. This good compatibility makes the surface of the material more uniform and smooth after curing; combined with the low-polarity acrylate resin monomer, which itself has a lower polarity and a lower curing shrinkage rate, it helps to reduce the uneven curing shrinkage caused by the surface tension gradient, thereby forming a smoother surface. (2) Optimization of rheological properties: Adding a rheological regulator (such as modified silicone oil or silicone polyether) can reduce the viscosity of the system and enhance the leveling of the material, so that the liquid resin can be better spread during the printing and curing process, fill in the fine area, thereby eliminating interlayer marks and improving surface smoothness. (3) Volume control during curing: The acrylic resin monomer selected a material with low shrinkage (such as IBOA) to avoid surface wrinkling or unevenness caused by volume changes during printing and curing.

[0073] It is further explained that the 3D printing resin composition for jewelry investment casting provided by the present invention improves the mechanical strength of the model through the following aspects: on the one hand, the introduction of monofunctional acrylate resin monomer also greatly improves the strength of the printed model; on the other hand, the oxidative grafting modification technology is used to give paraffin and microcrystalline wax polar groups (ester groups), so that they have good compatibility with low-polarity acrylate resin monomers (such as IBOA, IBOMA, DCPA, LMA, IDA) that also have ester groups, refine the crystallization of the wax material, and greatly improve the mechanical strength of the model; the addition of EVA (ethylene-vinyl acetate copolymer) further improves the flexibility and compatibility of the system and increases the mechanical strength of the model.

[0074] The second aspect of the present invention provides a method for preparing the 3D printing resin composition for jewelry investment casting, comprising the following steps:

[0075] The monofunctional acrylate resin monomer, oxidative graft modified petroleum wax, ethylene-vinyl acetate copolymer, photoinitiator, rheology modifier and ultraviolet absorber are mixed in a formulated amount to obtain the 3D printing resin composition for jewelry investment casting.

[0076] In some preferred embodiments, the oxidative grafted modified petroleum wax is prepared by the following preparation method:

[0077] Under the catalytic action of an acid agent, oxidized petroleum wax is mixed with a monofunctional small molecule alcohol to carry out a grafting reaction to obtain the oxidized grafted modified petroleum wax;

[0078] And / or, the mass percentage of the oxidized petroleum wax used is 78%-82%, and the mass percentage of the monofunctional small molecule alcohol used is 18%-22%;

[0079] Wherein, based on the total mass of the oxidized grafted modified petroleum wax as 100%, the addition amount of the oxidized petroleum wax is 78%-82%, for example, it can be 78%, 79%, 80%, 81%, 82%, etc.;

[0080] Taking the total mass of the oxidative grafted modified petroleum wax as 100%, the addition amount of the monofunctional small molecule alcohol is 18%-22%, for example, 18%, 19%, 20%, 21%, 22%, etc.

[0081] And / or, the amount of the acid agent used is 0.09%-0.11% of the mass of the oxidized petroleum wax and the monofunctional small molecule alcohol, for example, it can be 0.09%, 0.1%, 0.11%, etc.;

[0082] and / or, the acid agent comprises at least one of benzenesulfonic acid, p-toluenesulfonic acid, 98% concentrated sulfuric acid and phosphoric acid;

[0083] In the present invention, the acid agent can be an organic acid or an inorganic acid, wherein the organic acid is benzenesulfonic acid or p-toluenesulfonic acid, and the inorganic acid is 98% concentrated sulfuric acid or phosphoric acid.

[0084] And / or, the reaction temperature of the grafting reaction is 105-120°C, for example, 105°C, 100°C, 110°C, 120°C, etc.; the reaction time of the grafting reaction is 1.5-2.5 h, for example, 1.5 h, 2 h, 2.5 h, etc.;

[0085] And / or, the mixing process includes: mixing the heated and melted oxidized grafted modified petroleum wax and ethylene-vinyl acetate copolymer at a first temperature and stirring, then adding a monofunctional acrylate resin monomer at a second temperature, then adding a rheology modifier, and then adding an ultraviolet absorber and a photoinitiator;

[0086] and / or, the first temperature is 105-110° C., for example, 105° C., 106° C., 107° C., 108° C., 109° C., 110° C., etc.;

[0087] And / or, the stirring time is 85-95 min, for example, 85 min, 90 min, 95 min, etc.;

[0088] And / or, the second temperature is 85-95°C, for example, 85°C, 90°C, 95°C, etc.

[0089] The third aspect of the present invention provides a 3D printing resin composition for jewelry investment casting or the use of the preparation method in manufacturing jewelry investment casting.

[0090] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0091] The melt index of the ethylene-vinyl acetate copolymers in the following examples is less than 450 g / 10 min.

[0092] Example 1

[0093] This embodiment provides a 3D printing resin composition for jewelry investment casting, which includes the following components by mass percentage:

[0094] 33.8% rigid monofunctional acrylate resin monomer (IBOA), 35% flexible monofunctional acrylate resin monomer (LMA), 15% n-butanol oxidized grafted modified paraffin, 10% n-butanol oxidized grafted modified microcrystalline wax, 3% EVA (Honeywell AC-400A), 2% photoinitiator (TPO), 1% rheology regulator (polydimethylsiloxane) and 0.2% UV absorber (UV-326).

[0095] Example 2

[0096] This embodiment provides a 3D printing resin composition for jewelry investment casting, which includes the following components by mass percentage:

[0097] 50% rigid monofunctional acrylate resin monomer (DCPA), 25% flexible monofunctional acrylate resin monomer (LMA), 20% isopropyl alcohol oxidative grafted modified microcrystalline wax, 2% EVA (Formosa Plastics EVA-28 / 400), 1% photoinitiator (TPO-L), 1.7% rheology regulator (silicone acrylate) and 0.3% UV absorber (UV-327).

[0098] Example 3

[0099] This embodiment provides a 3D printing resin composition for jewelry investment casting, which includes the following components by mass percentage:

[0100] 42.42% rigid monofunctional acrylate resin monomer (IBOA), 28.28% flexible monofunctional acrylate resin monomer (LMA), 17% n-butanol oxidized grafted modified paraffin, 5% n-butanol oxidized grafted modified microcrystalline wax, 5% EVA (Honeywell AC-400A), 0.5% photoinitiator (TPO), 1.5% rheology regulator (modified silicone polyether) and 0.3% UV absorber (UV-384).

[0101] Example 4

[0102] This embodiment provides a 3D printing resin composition for jewelry investment casting, which includes the following components by mass percentage:

[0103] 38% rigid monofunctional acrylate resin monomer (IBOMA), 25% flexible monofunctional acrylate resin monomer (LA), 15% isobutyl alcohol oxidized grafted modified paraffin, 15% isobutyl alcohol oxidized grafted modified microcrystalline wax, 4% EVA (Formosa Plastics EVA-28 / 400), 1.5% photoinitiator (TPO-L), 1% rheology regulator (polydimethylsiloxane), 0.5% UV absorber (UV-P).

[0104] Example 5

[0105] This embodiment provides a 3D printing resin composition for jewelry investment casting, which includes the following components by mass percentage:

[0106] 30% rigid monofunctional acrylate resin monomer (TBCHA), 30.8% flexible monofunctional acrylate resin monomer (IDA), 35% n-propanol oxidized grafted modified paraffin, 1% EVA (Formosa EVA-28 / 400), 2% photoinitiator (TPO), 1% rheology regulator (silicone acrylate) and 0.2% UV absorber (Tinuvin 123).

[0107] Example 6

[0108] This embodiment provides a 3D printing resin composition for jewelry investment casting, which includes the following components by mass percentage:

[0109] 32.5% rigid monofunctional acrylate resin monomer (IBOA), 32.5% flexible monofunctional acrylate resin monomer (LMA), 8% n-butanol oxidized grafted modified paraffin, 20% n-butanol oxidized grafted modified microcrystalline wax, 4% EVA (Honeywell AC-400A), 1% photoinitiator (TPO), 1.5% rheology regulator (modified silicone polyether) and 0.5% UV absorber (UV-384).

[0110] Example 7

[0111] This embodiment provides a 3D printing resin composition for jewelry investment casting, which includes the following components by mass percentage:

[0112] 35% rigid monofunctional acrylate resin monomer (DCPA), 25% flexible monofunctional acrylate resin monomer (LMA), 31% isopropyl alcohol oxidative grafted modified microcrystalline wax, 3.9% EVA (Formosa EVA-28 / 400), 3% photoinitiator (TPO-L), 2% rheology regulator (silicone acrylate) and 0.1% UV absorber (UV-327).

[0113] Example 8

[0114] This embodiment provides a 3D printing resin composition for jewelry investment casting, which is different from Example 1 in that: 52% rigid monofunctional acrylate resin monomer (IBOA), 24% flexible monofunctional acrylate resin monomer (LMA), 7.8% n-butanol oxidized grafted modified paraffin, and the remaining components are consistent with Example 1.

[0115] Example 9

[0116] This embodiment provides a 3D printing resin composition for jewelry investment casting, which differs from Example 1 in that: 23% rigid monofunctional acrylate resin monomer (IBOA), 36% flexible monofunctional acrylate resin monomer (LMA), 24.8% n-butanol oxidized grafted modified paraffin, and the remaining components are consistent with Example 1.

[0117] Example 10

[0118] This embodiment provides a 3D printing resin composition for jewelry investment casting, which differs from Example 1 in that: 17.5% n-butanol oxidized grafted modified paraffin wax, 0.5% EVA (Honeywell AC-400A), and the remaining components are consistent with Example 1.

[0119] Embodiment 11

[0120] This embodiment provides a 3D printing resin composition for jewelry investment casting, which differs from Example 1 in that: 12% n-butanol oxidized grafted modified paraffin wax, 6% EVA (Honeywell AC-400A), and the remaining components are consistent with Example 1.

[0121] Example 12

[0122] This embodiment provides a 3D printing resin composition for jewelry investment casting, which is different from Embodiment 1 in that:

[0123] The monofunctional acrylate resin monomer only selected: 68.8% flexible monofunctional acrylate resin monomer (IBOA), and the rest was the same as in Example 1.

[0124] Embodiment 13

[0125] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Example 1 and specifically includes the following steps:

[0126] Step 1: Preparation method of n-butanol oxidized grafted modified paraffin: Mix 80% oxidized paraffin (Zhejiang Huangxing Chemical) with 20% n-butanol, add into a closed glass reactor with heating, negative pressure vacuum, stirring and other functions, add 0.1% of the total mass of the system benzenesulfonic acid, heat up with stirring, raise the temperature to about 110°C, then start negative pressure vacuum, small molecule alcohol and water formed by the reaction will form an azeotrope and be collected through a spherical condenser, react for 2 hours to obtain n-butanol oxidized grafted modified paraffin.

[0127] Step 2: Preparation method of n-butanol oxidized grafted modified microcrystalline wax: Mix 80% oxidized microcrystalline wax (Zhejiang Huangxing Chemical) with 20% n-butanol, add into a closed glass reactor with heating, negative pressure vacuum, stirring and other functions, add 0.1% benzenesulfonic acid of the total mass of the system, heat up with stirring, raise the temperature to about 110°C, then start negative pressure vacuum, small molecule alcohol and water formed by the reaction will form an azeotrope and be collected through a spherical condenser, react for 2 hours to obtain n-butanol oxidized grafted modified microcrystalline wax.

[0128] Step 3: Heat and melt the oxidized grafted modified paraffin wax and oxidized grafted modified microcrystalline wax, then add EVA, stir at 108°C for 90 minutes until completely dissolved, then add monofunctional acrylate resin monomer, stir and control the temperature at 90°C, then add rheology regulator, stir and mix evenly, then add UV absorber and photoinitiator, mix evenly and store in a dark bottle away from light.

[0129] Embodiment 14

[0130] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Example 2, and specifically includes the following steps:

[0131] Step 1: Preparation method of isopropanol oxidized grafted modified microcrystalline wax: Mix 80% oxidized microcrystalline wax (Zhejiang Huangxing Chemical) with 20% isopropanol, add into a closed glass reactor with heating, negative pressure vacuum, stirring and other functions, add 0.1% benzenesulfonic acid of the total mass of the system, heat up with stirring, heat to about 110°C, then start negative pressure vacuum, small molecule alcohol and water formed by the reaction will form azeotropes and be collected through a spherical condenser, react for 2 hours to obtain isopropanol oxidized grafted modified microcrystalline wax.

[0132] Step 2: Heat and melt the oxidized grafted modified microcrystalline wax, then add EVA, stir at 108°C for 90 minutes until completely dissolved, then add monofunctional acrylate resin monomer, stir and control the temperature at 90°C, then add rheology regulator, stir and mix evenly, then add UV absorber and photoinitiator, mix evenly and store in a dark bottle away from light.

[0133] Embodiment 15

[0134] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Example 3, and the preparation steps are consistent with Example 13.

[0135] Example 16

[0136] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Example 4. The difference from Example 13 is:

[0137] In the preparation step of the isobutyl alcohol oxidized grafted modified paraffin, oxidized paraffin is mixed with isobutyl alcohol;

[0138] In the preparation step of the isobutyl alcohol oxidized grafted modified microcrystalline wax, oxidized microcrystalline wax is mixed with isobutyl alcohol;

[0139] The remaining steps are consistent with Example 13.

[0140] Embodiment 17

[0141] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Example 5, and specifically includes the following steps:

[0142] Step 1: Preparation method of n-propanol oxidized grafted modified paraffin: Mix 80% oxidized paraffin (Zhejiang Huangxing Chemical) with 20% n-propanol, add into a closed glass reactor with heating, negative pressure vacuum, stirring and other functions, add 0.1% of the total mass of the system benzenesulfonic acid, heat up under stirring, heat to about 110°C, then start negative pressure vacuum, small molecule alcohol and water formed by the reaction will form an azeotrope and be collected through a spherical condenser, react for 2 hours to obtain n-propanol oxidized grafted modified paraffin.

[0143] Step 2: Heat and melt the oxidized grafted modified paraffin, then add EVA, stir at 108°C for 90 minutes until it is completely dissolved, then add the monofunctional acrylate resin monomer, stir and control the temperature at 90°C, then add the rheology regulator, stir and mix evenly, then add the UV absorber and photoinitiator, mix evenly and store in a dark bottle away from light.

[0144] Embodiment 18

[0145] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Example 6, and the preparation steps are consistent with Example 13.

[0146] Embodiment 19

[0147] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Example 7, and the preparation steps are consistent with Example 14.

[0148] Examples 20-24

[0149] Examples 20-24 provide a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Examples 8-12 respectively, and the preparation method is consistent with Example 13.

[0150] Embodiment 25

[0151] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component content of Example 1 and includes the following steps:

[0152] Step 1: Preparation method of n-butanol oxidized grafted modified paraffin: Mix 78% oxidized paraffin (Zhejiang Huangxing Chemical) with 22% n-butanol, add into a closed glass reactor with heating, negative pressure vacuum, stirring and other functions, add 0.09% benzenesulfonic acid of the total mass of the system, heat up with stirring, heat to about 105°C, then start negative pressure vacuum, small molecule alcohol and water formed by the reaction will form an azeotrope and be collected through a spherical condenser, react for 2.5 hours to obtain n-butanol oxidized grafted modified paraffin.

[0153] Step 2: Preparation method of n-butanol oxidized grafted modified microcrystalline wax: Mix 78% oxidized microcrystalline wax (Zhejiang Huangxing Chemical) with 22% n-butanol, add into a closed glass reactor with heating, negative pressure vacuum, stirring and other functions, add 0.09% of the total mass of the system benzenesulfonic acid, heat up with stirring, raise the temperature to about 105°C, then start negative pressure vacuum, small molecule alcohol and water formed by the reaction will form an azeotrope and be collected through a spherical condenser, react for 2.5 hours to obtain n-butanol oxidized grafted modified microcrystalline wax.

[0154] Step 3: Heat and melt the oxidized grafted modified paraffin wax and oxidized grafted modified microcrystalline wax, then add EVA, stir at 105°C for 95 min until completely dissolved, then add the monofunctional acrylate resin monomer, stir and control the temperature at 85°C, then add the rheology regulator, stir and mix evenly, then add the UV absorber and photoinitiator, mix evenly and store in a dark bottle away from light.

[0155] Embodiment 26

[0156] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component content of Example 1 and includes the following steps:

[0157] Step 1: Preparation method of n-butanol oxidized grafted modified paraffin: Mix 82% oxidized paraffin (Zhejiang Huangxing Chemical) with 18% n-butanol, add into a closed glass reactor with heating, negative pressure vacuum, stirring and other functions, add 0.11% of the total mass of the system benzenesulfonic acid, heat up with stirring, raise the temperature to about 120°C, then start negative pressure vacuum, small molecule alcohol and water formed by the reaction will form an azeotrope and be collected through a spherical condenser, react for 1.5 hours to obtain n-butanol oxidized grafted modified paraffin.

[0158] Step 2: Preparation method of n-butanol oxidized grafted modified microcrystalline wax: Mix 82% oxidized microcrystalline wax (Zhejiang Huangxing Chemical) with 18% n-butanol, add into a closed glass reactor with heating, negative pressure vacuum, stirring and other functions, add 0.11% of the total mass of the system benzenesulfonic acid, heat up with stirring, raise the temperature to about 120°C, then start negative pressure vacuum, small molecule alcohol and water formed by the reaction will form an azeotrope and be collected through a spherical condenser, react for 1.5 hours to obtain n-butanol oxidized grafted modified microcrystalline wax.

[0159] Step 3: Heat and melt the oxidized grafted modified microcrystalline wax, then add EVA, stir at 110°C for 85 min until completely dissolved, then add the monofunctional acrylate resin monomer, stir and control the temperature at 95°C, then add the rheology regulator, stir and mix evenly, then add the UV absorber and photoinitiator, mix evenly and store in a dark bottle away from light.

[0160] Embodiment 27

[0161] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents of embodiment 1, and the difference from embodiment 13 is:

[0162] In step 1, 77% oxidized paraffin (Zhejiang Huangxing Chemical) was mixed with 23% n-butanol, and 0.08% of the total mass of the system was added with benzenesulfonic acid;

[0163] In step 2, 77% oxidized microcrystalline wax (Zhejiang Huangxing Chemical) was mixed with 23% n-butanol, and 0.08% benzenesulfonic acid was added to the total mass of the system.

[0164] Embodiment 28

[0165] This embodiment provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents of embodiment 1, and the difference from embodiment 13 is:

[0166] In step 1, 83% oxidized paraffin (Zhejiang Huangxing Chemical) was mixed with 17% n-butanol, and 0.12% of the total mass of the system was added with benzenesulfonic acid;

[0167] In step 2, 83% oxidized microcrystalline wax (Zhejiang Huangxing Chemical) was mixed with 17% n-butanol, and 0.12% of benzenesulfonic acid was added to the total mass of the system.

[0168] Application Example 1-16

[0169] Application Examples 1-16 provide a method for preparing jewelry investment patterns, which are prepared using the 3D printing resin composition materials prepared in Examples 13-28, and specifically include the following steps:

[0170] Step (a): the prepared printing material is filtered under pressure through a filter equipped with a filter membrane with a pore size of 10 microns, and directly filtered into an ink barrel for a printer, and then printed on the machine, and solidified layer by layer to obtain a model with support material, and the wax model with support material is placed in a special cleaning liquid to clean and remove the support material, so as to obtain a wax model to be used for investment casting;

[0171] Step (b): The tensile strength and bending strength of the obtained model part are tested, and the other part is investment cast, and the surface roughness of the obtained finished product is tested.

[0172] Comparative Example 1

[0173] This comparative example provides a 3D printing resin composition for jewelry investment casting, which is different from Example 1 in that 15% paraffin wax and 10% microcrystalline wax are used, that is, the paraffin wax and the microcrystalline wax are not modified, and the other components are consistent with Example 1.

[0174] Comparative Example 2

[0175] This comparative example provides a pure wax printing material, which includes the following components by mass percentage:

[0176] 30% petroleum resin (Japanese Arakawa P-90), 57% paraffin, 10% microcrystalline wax and 3% EVA (Honeywell AC-400A).

[0177] Comparative Example 3

[0178] This comparative example provides a 3D printing resin composition for jewelry investment casting, which differs from Example 1 in that EVA is not added and the monofunctional acrylate resin monomer (IBOA) is 36.8%.

[0179] Comparative Example 4

[0180] This comparative example provides a 3D printing resin composition for jewelry investment casting, which differs from Example 1 in that no rheology modifier is added, and the monofunctional acrylate resin monomer (IBOA) is 34.8%.

[0181] Comparative Example 5

[0182] This comparative example provides a 3D printing resin composition for jewelry investment casting, which differs from Example 1 in that the monofunctional acrylate resin monomer (IBOA) is replaced with a difunctional monomer DCPDA (tricyclodecane dimethanol diacrylate).

[0183] Comparative Example 6

[0184] This comparative example provides a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component content in comparative example 1, and specifically includes the following steps:

[0185] Step 1: Heat and melt the paraffin wax and microcrystalline wax, then add EVA, stir at 108°C for 90 minutes until completely dissolved, then add the monofunctional acrylate resin monomer, stir and control the temperature at 90°C, then add the rheology regulator, stir and mix evenly, then add the UV absorber and photoinitiator, mix evenly and store in a dark bottle away from light.

[0186] Comparative Example 7

[0187] This comparative example provides a method for preparing a pure wax printing material, which is prepared using the component content in comparative example 2, and specifically includes the following steps:

[0188] Step 1: Heat and melt paraffin and microcrystalline wax, then add EVA, stir at 108℃ for 90min until completely dissolved, then add petroleum resin, stir and control the temperature at 85-95℃, and stir and mix evenly.

[0189] Comparative Examples 8-10

[0190] Comparative Examples 8-10 provide a method for preparing a 3D printing resin composition for jewelry investment casting, which is prepared using the component contents in Comparative Examples 3-5, respectively, and the preparation steps are consistent with Example 13.

[0191] Comparative Application Examples 1-5

[0192] Comparative Application Examples 1-5 provide a method for preparing jewelry investment molds, which are prepared using the printing resin compositions prepared in Comparative Examples 6-10, respectively. The preparation method is consistent with Application Example 1.

[0193] Test samples: The jewelry molds prepared in Application Examples 1-16 and the jewelry molds prepared in Comparative Application Examples 1-5 were used as samples.

[0194] Test method:

[0195] The bending strength of the samples was tested according to GB / T9341;

[0196] The tensile strength of the samples was tested according to GB / T1040;

[0197] The surface roughness of the sample was tested using the KEYENCE 3D profile measuring instrument VR-6000 series produced by KEYENCE (the testing instrument can measure surface roughness types such as Sa and Sz in accordance with ISO25178 standard). The testing conditions are: test temperature 22-25°C, humidity ≤80%.

[0198] The test results are shown in Table 1.

[0199] Table 1

[0200]

[0201] It can be seen from the data in Table 1 that the formula of comparative application example 1 is paraffin and microcrystalline wax that have not been oxidized and grafted. The printed model is brittle, so the bending strength and tensile strength are very low. The reason is that after the resin monomer is solidified into a polymer, the compatibility of paraffin and microcrystalline wax with it becomes very poor, and phase separation occurs, which cannot play a toughening role, and the crystallization is rough, so the mechanical properties are greatly reduced, and the surface roughness is poor. Comparative example 2 is a pure wax printing material, which does not contain a photosensitive resin component. The mechanical strength of the printed model is worse than that of application examples 1 to 16. Since it does not contain a photosensitive resin, the fluidity is poor, and the roughness of the finished casting is also poor. Comparative application examples 3-4 do not contain EVA and rheology regulators, respectively. The results show that the comprehensive performance of their products is worse than that of application example 1; comparative application example 5 uses a difunctional monomer to replace the monofunctional acrylate resin monomer. Compared with application example 1, the mold performance will be greatly reduced after the replacement, and the surface is very rough.

[0202] The result data of Application Examples 1 and 12 show that, compared with Application Example 12, Application Example 1 uses a compound of rigid and flexible monofunctional acrylate resin monomers, and its product has high flexural strength and tensile strength, and the product surface is smoother. The result data of Application Examples 1 and 15 show that the performance difference between the two products is not large, but Application Example 15 uses excessive isopropanol, which will increase the cost; compared with Application Examples 8-11, Application Example 1 uses a product with a specific component ratio, and its comprehensive performance is better.

[0203] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A 3D printing resin composition for jewelry investment casting, characterized in that: The following components are included by mass percentage: 60%-75% monofunctional acrylate resin monomer, 20%-35% oxidative graft modified petroleum wax, 1%-5% ethylene-vinyl acetate copolymer, 0.5%-3% photoinitiator, 1%-2% rheology modifier and 0.1%-0.5% UV absorber; The oxidized grafted modified petroleum wax is prepared by introducing an ester group through a grafting reaction between oxidized petroleum wax and a monofunctional small molecule alcohol; The monofunctional acrylate resin monomer is a low-polar monofunctional acrylate resin monomer.

2. The 3D printing resin composition for jewelry investment casting according to claim 1, characterized in that: The oxidized petroleum wax includes at least one of oxidized paraffin and oxidized microcrystalline wax; The monofunctional small molecule alcohol includes at least one of n-butanol, isobutanol, propanol and isopropanol.

3. The 3D printing resin composition for jewelry investment casting according to claim 1, characterized in that: The monofunctional acrylate resin monomer includes at least one of a rigid monofunctional acrylate resin monomer and a flexible monofunctional acrylate resin monomer; The rigid monofunctional acrylate resin monomer includes at least one of isobornyl acrylate, isobornyl methacrylate, dicyclopentadiene acrylate, and 4-tert-butylcyclohexyl acrylate, and the flexible monofunctional acrylate resin monomer includes at least one of isodecyl acrylate, lauryl acrylate, and lauryl methacrylate; The rigid monofunctional acrylate resin monomer accounts for 30%-50% of the total mass of the 3D printing resin composition, and the flexible monofunctional acrylate resin monomer accounts for 25%-35% of the total mass of the 3D printing resin composition; The melt index of the ethylene-vinyl acetate copolymer is less than 450 g / 10 min.

4. The 3D printing resin composition for jewelry investment casting according to claim 1, characterized in that: The photoinitiator includes at least one of TPO-L and TPO.

5. The 3D printing resin composition for jewelry investment casting according to claim 1, characterized in that: The rheology modifier includes at least one of polydimethylsiloxane, silicone acrylate and modified silicone polyether.

6. The 3D printing resin composition for jewelry investment casting according to claim 1, characterized in that: The ultraviolet absorber includes at least one of UV-326, Tinuvin 123 and UV-384.

7. The method for preparing a 3D printing resin composition for jewelry investment casting according to any one of claims 1 to 6, characterized in that: The following steps are involved: The monofunctional acrylate resin monomer, oxidative graft modified petroleum wax, ethylene-vinyl acetate copolymer, photoinitiator, rheology modifier and ultraviolet absorber are mixed in a formulated amount to obtain the 3D printing resin composition for jewelry investment casting.

8. The method for preparing a 3D printing resin composition for jewelry investment casting according to claim 7, characterized in that: The oxidative grafted modified petroleum wax is prepared by the following preparation method: Under the catalytic action of an acid agent, oxidized petroleum wax is mixed with a monofunctional small molecule alcohol to carry out a grafting reaction to obtain the oxidized grafted modified petroleum wax; The mass percentage of the oxidized petroleum wax used is 78%-82%, and the mass percentage of the monofunctional small molecule alcohol used is 18%-22%; The amount of the acid agent used is 0.09%-0.11% of the total mass of the oxidized petroleum wax and the monofunctional small molecule alcohol; The acid agent comprises at least one of benzenesulfonic acid, p-toluenesulfonic acid, 98% concentrated sulfuric acid and phosphoric acid; The reaction temperature of the grafting reaction is 105-120°C, and the reaction time is 1.5-2.5 h; The mixing process comprises: mixing the heated and melted oxidized grafted modified petroleum wax and ethylene-vinyl acetate copolymer at a first temperature and stirring, then adding a monofunctional acrylate resin monomer at a second temperature, then adding a rheology regulator, and then adding an ultraviolet absorber and a photoinitiator; The first temperature is 105-110°C; The stirring time is 85-95 min; The second temperature is 85-95°C.

9. Use of the 3D printing resin composition for jewelry investment casting according to any one of claims 1 to 6 or the preparation method according to claim 7 or 8 in manufacturing jewelry investment casting.

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