Dental material impact modifier comprising nano-sized particles, and dental medical device comprising same

Abstract

The present invention relates to an dental material impact modifier and a dental medical device comprising same, the impact modifier being composed of nano-sized particles and comprising: a core layer in which a C2-18 alkyl acrylate monomer or a C2-18 alkyl methacrylate monomer and a cross-linkable monomer are copolymerized; a rubber layer which is positioned on the core layer, and in which an acrylate monomer and a cross-linking monomer are copolymerized; and an outer layer which is positioned on the rubber layer, and in which methacrylate monomers are copolymerized. According to the present invention, the dental material impact modifier and the dental medical device comprising same can be provided, the modifier being capable of improving flexural strength and flexural modulus while lowering the transparency of an acrylic material.

Description

Impact modifier for dental materials containing nano-sized particles and dental medical devices containing the same

[0001] The present invention relates to an impact modifier for dental materials having nano-sized particles and a dental medical device comprising the same, and more particularly, to an impact modifier for dental materials comprising a core layer copolymerized with an alkyl acrylate monomer having 2 to 18 carbon atoms or an alkyl methacrylate monomer having 2 to 18 carbon atoms and a crosslinking monomer; a rubber layer positioned on the core layer and copolymerized with an acrylate monomer and a crosslinking monomer; and an outer layer positioned on the rubber layer and copolymerized with a methacrylate monomer; and to an impact modifier for dental materials comprising nano-sized particles and a dental medical device comprising the same.

[0002] The dental biomaterials market has an average annual growth rate of 6.57%, and the dental 3D printing market has an average annual growth rate of 25.8%, showing remarkable growth in the dental market due to improved living standards and extended life expectancy.

[0003] Conventional denture base resins (dentures) and crown resins (artificial teeth) are made by mixing acrylic polymers such as polymethyl methacrylate and polyethyl acrylate, monomers such as methyl methacrylate, ethacrylate, and butyl acrylate, and crosslinking agents, catalysts, initiators, etc.

[0004] However, since the physical properties of dental medical devices products made by mixing polymer materials and monomers are generally low, there is a need to improve the physical properties.

[0005] Conventional technologies regarding impact modifiers include an acrylic impact modifier (Patent No. 10-2168346), an impact modifier for methacrylic resin with excellent impact strength and optical properties and a method for producing the same (Patent No. 10-1497756), etc. However, since the above-mentioned conventional technologies have resin compositions that mix polymer materials and monomers, the physical properties are low, and therefore, there is a need to improve the physical properties.

[0006] (Prior art literature)

[0007] (Patent Document)

[0008] (Patent Document 1) Patent Registration No. 10-2168346

[0009] (Patent Document 2) Patent Registration No. 10-1497756

[0010] The present invention is intended to solve the problems of the prior art as described above, and the purpose of the present invention is to provide an impact modifier having a three-layer structure through emulsion polymerization to supplement the low flexural strength and flexural elastic modulus of acrylic materials.

[0011] Another object of the present invention is to provide a dental medical device that can increase flexural strength and flexural elastic modulus while lowering the excellent transparency of an acrylic material by including the impact modifier.

[0012] In order to achieve the above object, the present invention provides an impact modifier for dental materials comprising a core layer copolymerized with an alkyl acrylate monomer having 2 to 18 carbon atoms or an alkyl methacrylate monomer having 2 to 18 carbon atoms and a crosslinking monomer; a rubber layer positioned on the core layer and copolymerized with the acrylate monomer and the crosslinking monomer; and an outer layer positioned on the rubber layer and copolymerized with the methacrylate monomer; and made of nano-sized particles.

[0013] As one embodiment of the present invention, the alkyl acrylate having 2 to 18 carbon atoms may be at least one selected from the group consisting of ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, and allyl acrylate.

[0014] In one embodiment of the present invention, the alkyl methacrylate having 2 to 18 carbon atoms may be at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, and cyclohexyl methacrylate.

[0015] As one embodiment of the present invention, the crosslinking monomer may be at least one selected from the group consisting of 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol methacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, allyl methacrylate, trimethylolpropane triacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, polyethylene glycol acrylate, polyethylene glycol methacrylate, butylene glycol dimethacrylate, tert-butyl hydroperoxide, and hexyl hydroxyacrylate.

[0016] As one embodiment of the present invention, the acrylate monomer may be at least one selected from the group consisting of methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butylacrylate, t-butylacrylate, pentylacrylate, hexylacrylate, heptylacrylate, octylacrylate, 2-ethylhexylacrylate, nonylacrylate, decylacrylate, lauryl acrylate, n-tetradecylacrylate, and stearyl acrylate.

[0017] As one embodiment of the present invention, the methacrylate monomer may be at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, and stearyl methacrylate.

[0018] In one embodiment of the present invention, the impact modifier may further include at least one crosslinking agent selected from the group consisting of aryl methacrylate, 1,3-butylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimenacrylate, propylene glycol dimethacrylate, polyethylene glycol dimethacrylate, hexanediol dimethacrylate, trimethylol propane trimethacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, polyethylene glycol diacrylate, hexanediol diacrylate, trimethylol propane triacrylate, diallyl phthalate, diphenyl maleate, divinyl adipate, triallyl cyanurate, and triallyl isocyanate.

[0019] As one embodiment of the present invention, the core layer may be copolymerized with 1 to 10 parts by weight of the crosslinking monomer relative to 100 parts by weight of the alkyl acrylate monomer having 2 to 18 carbon atoms or the alkyl methacrylate monomer having 2 to 18 carbon atoms.

[0020] As one embodiment of the present invention, the rubber layer may be copolymerized with 0.1 to 5 parts by weight of the crosslinking monomer based on 100 parts by weight of the acrylate monomer.

[0021] As one embodiment of the present invention, the nano size may be 100 to 500 nm.

[0022] In addition, the present invention provides a dental medical device including the impact modifier to achieve the above-described purpose.

[0023] As an embodiment of the present invention, the dental medical device may be at least one selected from the group consisting of denture materials, denture base materials, aesthetic treatment, direct restorative materials, dental bonding cements, dental impression materials, and dental orthodontic materials.

[0024] The impact modifier for dental materials according to the present invention has the advantage of improving impact resistance by increasing the rubber layer, which is the impact-absorbing layer of the impact modifier, due to the characteristics of dental medical devices using the same, such as artificial teeth or denture materials that are translucent materials, and also the nano- or micro-sized impact modifier according to the present invention has the advantage of being easy to mix with inorganic fillers.

[0025] In addition, the impact modifier for dental materials according to the present invention has the advantage of improving flexural strength and flexural elastic modulus while lowering the transparency of acrylic materials.

[0026] Figure 1 is a schematic diagram of an impact modifier according to one embodiment of the present invention.

[0027] Hereinafter, preferred embodiments of the present invention and the properties of each component will be described in detail. However, this is intended to be a detailed description to enable a person having ordinary knowledge in the technical field to which the present invention pertains to easily carry out the invention, and does not mean that the technical idea and scope of the present invention are limited thereby.

[0028] A first embodiment of the present invention relates to an impact modifier for dental materials comprising a core layer copolymerized with an alkyl acrylate monomer having 2 to 18 carbon atoms or an alkyl methacrylate monomer having 2 to 18 carbon atoms and a crosslinking monomer; a rubber layer positioned on the core layer and copolymerized with the acrylate monomer and the crosslinking monomer; and an outer layer positioned on the rubber layer and copolymerized with the methacrylate monomer; and comprising nano-sized particles.

[0029] The above core layer serves to maintain the shape of the impact modifier, and the alkyl acrylate having 2 to 18 carbon atoms may be at least one selected from the group consisting of ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, and allyl acrylate, but is not limited thereto.

[0030] In the core layer, the alkyl methacrylate having 2 to 18 carbon atoms may be at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, and cyclohexyl methacrylate, but is not limited thereto.

[0031] In the above core layer, the crosslinking monomer may be at least one selected from the group consisting of 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol methacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, allyl methacrylate, trimethylolpropane triacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, polyethylene glycol acrylate, polyethylene glycol methacrylate, butylene glycol dimethacrylate, tert-butyl hydroperoxide, and hexyl hydroxyacrylate, but is not limited thereto.

[0032] The above rubber layer is a layer that absorbs external shocks and exhibits a low glass transition temperature (Tg) like rubber at room temperature (below room temperature, i.e., below 20°C) and has the characteristic of becoming soft at room temperature.

[0033] In the above rubber layer, the acrylate monomer may be at least one selected from the group consisting of methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butylacrylate, t-butylacrylate, pentylacrylate, hexylacrylate, heptylacrylate, octylacrylate, 2-ethylhexylacrylate, nonylacrylate, decylacrylate, lauryl acrylate, n-tetradecylacrylate, and stearyl acrylate, but is not limited thereto.

[0034] In the above rubber layer, the crosslinking monomer has been described in the core layer, so a detailed description thereof is omitted.

[0035] The above outer (shell) layer must maintain compatibility with the base material and, because it requires solubility, must maintain a certain molecular weight.

[0036] In the above outer layer, the methacrylate monomer may be at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, and stearyl methacrylate, but is not limited thereto.

[0037] The above impact modifier may further include at least one crosslinking agent selected from the group consisting of aryl methacrylate, 1,3-butylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimenacrylate, propylene glycol dimethacrylate, polyethylene glycol dimethacrylate, hexanediol dimethacrylate, trimethylol propane trimethacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, polyethylene glycol diacrylate, hexanediol diacrylate, trimethylol propane triacrylate, diallyl phthalate, diphenyl maleate, divinyl adipate, triallyl cyanurate, and triallyl isocyanate, but is not limited thereto.

[0038] In the above impact modifier, emulsifiers, initiators, etc. commonly used in the copolymerization may be used, but since it is sufficient to use emulsifiers, initiators, etc. commonly used in the art, a detailed description thereof is omitted.

[0039] The particle size of the above impact modifier may be 100 to 500 nm, preferably 250 to 500 nm, and more preferably 300 to 450 nm. When the particle size is less than 100 nm, transparency increases, but more impact modifier is required to increase flexural modulus, whereas when the particle size exceeds 500 nm, the physical properties tend to deteriorate, which is not desirable.

[0040] The core layer may be copolymerized with 1 to 10 parts by weight, preferably 3 to 7 parts by weight, of the crosslinking monomer based on 100 parts by weight of the alkyl acrylate monomer having 2 to 18 carbon atoms or the alkyl methacrylate monomer having 2 to 18 carbon atoms, but is not limited thereto. If the crosslinking monomer is less than 1 part by weight, a problem of polymerization not occurring occurs, and if the crosslinking monomer exceeds 10 parts by weight, a problem of unbalanced core particle uniformity and particle size occurs, which is not preferable.

[0041] The above rubber layer may be copolymerized with 0.1 to 5 parts by weight of the crosslinking monomer relative to 100 parts by weight of the acrylate monomer, but is not limited thereto. If the crosslinking monomer is less than 0.1 parts by weight, a problem of polymerization not occurring occurs, and if the crosslinking monomer exceeds 5 parts by weight, a problem of unbalanced core particle uniformity and particle size occurs, which is not preferable.

[0042] The heat resistance (Tg) of the above rubber layer may be -30 to 20°C. If the heat resistance is below -30°C, there is a problem of stability being broken during the polymerization stage, and if it is above 20°C, there is a problem of the effect of the impact modifier being reduced.

[0043] A second embodiment of the present invention relates to a dental medical device including the impact modifier.

[0044] The above dental medical device may be at least one selected from the group consisting of denture materials, denture base materials, aesthetic treatment, direct restorative materials, dental bonding cements, dental impression materials, dental orthodontic materials, and artificial teeth, but is not limited thereto.

[0045] Hereinafter, the present invention will be described in detail using examples to aid understanding. However, the examples according to the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited to the following examples. The examples of the present invention are provided to more fully explain the present invention to those of average skill in the art.

[0046]

[0047] <Example 1> Preparation of acrylic impact modifier

[0048] 1. Preparation of acrylic impact modifier with nanoparticles

[0049] The core layer was prepared by placing 1,000 g of distilled water, 0.008 g of ferrous sulfate, 0.04 g of EDTA·2Na, 0.5 g of sodium sulfoxylate formaldehyde, and 0.2 g of sodium dodecyl sulfate in a 2 L reactor stirred at 400 rpm, and heating to 80°C while adding nitrogen. A mixed solution of 69.5 wt% of methyl methacrylate, 30 wt% of ethyl acrylate, 0.3 wt% of 1,4 butanediol methacrylate, and 0.05 wt% of tert-butyl hydroperoxide was added dropwise over 3 hours, and then emulsion polymerization was performed by stirring at 400 rpm for 2 hours. At this time, the average particle size was 100 nm.

[0050] In the rubber layer, 0.002 wt% of ferrous sulfate, 0.004 wt% of EDTA·2Na salt, 0.1 wt% of sodium formaldehyde sulfoxylate, and 1.8 wt% of sodium dodecyl sulfate were added following the glass-like seed particles manufactured in the core layer manufacturing step.

[0051] Here, a mixed solution of 53.6 wt% of butylacrylate, 20.4 wt% of ethylacrylate, 0.2 wt% of 1,4-butanediol dimethacrylate, and 0.2 wt% of tert-butyl hydroperoxide was added dropwise over 5 hours, and then polymerized at 80°C for 2.5 hours. The average particle diameter of the polymer obtained at this time was 300 nm.

[0052] The outer layer was prepared by adding a mixed solution of 14.25 wt% ethyl methacrylate, 0.75 wt% methyl acrylate, 0.03 wt% n-octyl mercaptan, and 0.02 wt% tert-butyl hydroperoxide dropwise over 2 hours while maintaining the temperature at 80°C, followed by polymerization for 1.5 hours. The average particle diameter of the final polymer, the medical impact modifier, was 360 nm.

[0053]

[0054] 2. Preparation of micro-particle impact modifier

[0055] 300 g of an emulsion containing an impact modifier having the above nanoparticles, 1,200 g of methyl methacrylate, 3,000 g of distilled water, 10 g of an aqueous solution of polyvinyl alcohol (PVA217 of Kuraray) having a solid content of 5 wt%, and 0.1 g of boric acid were added, and 2.0 g of n-octyl mercaptan and 15 g of benzoyl peroxide were added to a 5 L glass reactor, and then dispersed in the water phase while stirring at 500 rpm.

[0056] Polymerization was performed at a polymerization temperature of 70℃ for 180 minutes, the solid and suspension were separated using a Buchner funnel, the solid was washed 2-3 times, and then drying was completed using a vacuum dryer at 60℃ for 24 hours. The final particle size was 52㎛.

[0057]

[0058] 3. Preparation and measurement of specimens

[0059] Dried microparticles and methyl methacrylate monomer were mixed in a 65:35 ratio, and 0.5% by volume of red 1.5D cellulose acetate fibers were added. The mixture was then placed in a mold conforming to ISO specimen specifications and polymerized at 80°C for 3 hours. Various physical properties were measured using the resulting specimens. The physical properties are shown in Table 1 below.

[0060]

[0061] <Example 2> Preparation of acrylic impact modifier

[0062] In the above Example 1, 6 g of polyvinyl alcohol aqueous solution and 0.06 g of boric acid were added in the micro particle formation step, and final 82 μm particles were produced. The physical properties are shown in Table 1 below.

[0063]

[0064] <Example 3> Preparation of acrylic impact modifier

[0065] In the micro particle formation step of Example 1, 14 g of polyvinyl alcohol aqueous solution and 0.12 g of boric acid were added to produce final 40 μm particles. The physical properties are shown in Table 1 below.

[0066]

[0067] <Comparative Example 1> Manufacturing of acrylic impact modifier

[0068] In the above Example 1, during the manufacturing step of the acrylic impact modifier, the average particle diameter including the rubber layer was 220 nm, and the final particle diameter was 271 nm. In the micro-particleization step, the final particle diameter was 51 μm. The physical properties are shown in Table 1 below.

[0069]

[0070] <Comparative Example 2> Manufacturing of acrylic impact modifier

[0071] In the above comparative example 1, 6 g of polyvinyl alcohol aqueous solution and 0.06 g of boric acid were added in the micro particle formation step, and final 85 μm particles were produced. The physical properties are shown in Table 1 below.

[0072]

[0073] <Comparative Example 3> Manufacturing of acrylic impact modifier

[0074] In the above comparative example 1, 14 g of polyvinyl alcohol aqueous solution and 0.12 g of boric acid were added in the micro particle formation step, and final 44 μm particles were produced. The physical properties are shown in Table 1 below.

[0075]

[0076] <Comparative Example 4> Manufacturing of acrylic impact modifier

[0077] In the above Example 1, during the manufacturing step of the acrylic impact modifier, the average particle diameter including the rubber layer was 340 nm, and the final particle diameter was 551 nm. In the micro-particleization step, the final particle diameter was 51 μm. The physical properties are shown in Table 1 below.

[0078]

[0079] <Comparative Example 5> Manufacturing of acrylic impact modifier

[0080] In the above comparative example 4, 6 g of polyvinyl alcohol aqueous solution and 0.06 g of boric acid were added in the micro particle formation step, and final 81 μm particles were produced. The physical properties are shown in Table 1 below.

[0081]

[0082] <Comparative Example 6> Manufacturing of acrylic impact modifier

[0083] In Comparative Example 6, 14 g of polyvinyl alcohol aqueous solution and 0.12 g of boric acid were added in the micro particle formation step, and final 43 μm particles were produced. The physical properties are shown in Table 1 below.

[0084]

[0085] <Comparative Example 7> Manufacturing of acrylic impact modifier

[0086] A mixture of high-molecular-weight polymethyl methacrylate particles with an average particle size of 70 um and methyl methacrylate monomer in a 65:35 ratio, with 0.5% by volume of red 1.5D cellulose acetate fiber, was kneaded, placed in a mold meeting ISO specimen specifications, and polymerized under conditions of 80°C and 3 hours. Various physical properties were measured using the specimens manufactured in this manner. The physical properties are shown in Table 1 below.

[0087]

[0088] As can be seen in Table 1 above, it was finally confirmed that the impact modifier size of 360 nm and the final microparticle size of 52 μm showed the main flexural strength and flexural modulus in teeth. In Comparative Example 7, it was confirmed that the material including the impact modifier had higher flexural strength and flexural modulus overall when compared to materials generally used in dental medical devices.

[0089] Furthermore, while transparency increases as the size of the impact modifier decreases within the same material, more impact modifier is required to increase flexural modulus. Conversely, it was confirmed that when impact modifiers exceeding a certain size are manufactured, their physical properties actually deteriorate.

[0090] While acrylic offers excellent transparency, materials used in dental devices are typically translucent, mirroring the color of teeth. The present invention has produced a dental device material that enhances flexural strength and elastic modulus while lowering the transparency of acrylic.

[0091]

[0092] As described above, specific parts of the present invention have been described in detail. It will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and that the scope of the present invention is not limited thereby.

[0093] Accordingly, the substantial scope of the present invention is defined by the appended claims and their equivalents. Simple modifications and variations of the present invention can be readily employed by those skilled in the art, and all such modifications and variations are deemed to fall within the scope of the present invention.

Claims

1. A core layer copolymerized with an alkyl acrylate monomer having 2 to 18 carbon atoms or an alkyl methacrylate monomer having 2 to 18 carbon atoms, and a crosslinking monomer; A rubber layer positioned on the core layer and in which an acrylate monomer and a crosslinking monomer are copolymerized; and An outer layer positioned on the rubber layer and comprising a methacrylate monomer copolymerized therein; An impact modifier for dental materials, made of nano-sized particles.

2. An impact modifier for dental materials, characterized in that in paragraph 1, the alkyl acrylate having 2 to 18 carbon atoms is at least one selected from the group consisting of ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, and allyl acrylate.

3. An impact modifier for dental materials, characterized in that in claim 1, the alkyl methacrylate having 2 to 18 carbon atoms is at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, and cyclohexyl methacrylate.

4. An impact modifier for dental materials, characterized in that in the first paragraph, the crosslinking monomer is at least one selected from the group consisting of 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol methacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, allyl methacrylate, trimethylolpropane triacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, polyethylene glycol acrylate, polyethylene glycol methacrylate, butylene glycol dimethacrylate, tert-butyl hydroperoxide, and hexyl hydroxyacrylate.

5. An impact modifier for dental materials, characterized in that in paragraph 1, the acrylate monomer is at least one selected from the group consisting of methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butylacrylate, t-butylacrylate, pentylacrylate, hexylacrylate, heptylacrylate, octylacrylate, 2-ethylhexylacrylate, nonylacrylate, decylacrylate, lauryl acrylate, n-tetradecylacrylate, and stearyl acrylate.

6. An impact modifier for dental materials, characterized in that in the first paragraph, the methacrylate monomer is at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, and stearyl methacrylate.

7. In the first paragraph, the impact modifier further comprises at least one crosslinking agent selected from the group consisting of aryl methacrylate, 1,3-butylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimenacrylate, propylene glycol dimethacrylate, polyethylene glycol dimethacrylate, hexanediol dimethacrylate, trimethylol propane trimethacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, polyethylene glycol diacrylate, hexanediol diacrylate, trimethylol propane triacrylate, diallyl phthalate, diphenyl maleate, divinyl adipate, triallyl cyanurate, and triallyl isocyanate. Shock absorber.

8. In paragraph 1, The core layer is copolymerized with 1 to 10 parts by weight of the crosslinking monomer relative to 100 parts by weight of the alkyl acrylate monomer having 2 to 18 carbon atoms or the alkyl methacrylate monomer having 2 to 18 carbon atoms. The above rubber layer is crosslinked with respect to 100 parts by weight of the above acrylate monomer. An impact modifier for dental materials characterized in that 0.1 to 5 parts by weight of a monomer is copolymerized.

9. An impact modifier for dental materials, characterized in that the nano size in the first paragraph is 100 to 500 nm.

10. A dental medical device comprising an impact modifier according to any one of claims 1 to 9.

11. In paragraph 10, the dental medical device is characterized in that it is at least one selected from the group consisting of denture materials, denture base materials, aesthetic treatment, direct restorative materials, dental bonding cements, dental impression materials, dental orthodontic materials, and artificial teeth.

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