Method for producing polyurethane-based composite material

Abstract

To prevent surface whitening of a molded body that occurs when producing a polyurethane-based composite molded body by cast molding a raw material composition including radical polymerizable polyurethane components having a number average molecular weight of 1500 to 5000 (A), non-chain-transfer radical polymerizable monomers (B), a thermal radical polymerization initiator (C) and inorganic fillers (D) in a predetermined proportion with a resin molding die.SOLUTION: Using a glass transition temperature: TG of 35 to 65°C as one described in (A), and using the other with a half-life temperature of 10 hours: T10 that is at least 50°C higher than TG and does not exceed 125°C as described in (C), after filling the mold with the raw material composition, it is held for 10 to 168 hours at a temperature that is 10°C lower than T10, and then held for 5 to 72 hours at a temperature that is 25°C higher than T10 for polymerization curing.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a polyurethane-based composite material.

Background Art

[0002] In dental treatment, in recent years, a method using a dental CAD / CAM system has been attracting attention as a technique for producing dental prostheses such as inlays, onlays, crowns, bridges, and implant superstructures. This method produces a dental prosthesis by cutting a dental blank (also called a "mill blank") with a computer-controlled cutting machine based on the three-dimensional coordinate data of the dental prosthesis designed by CAD, and can significantly reduce the time and labor required for production compared to conventional methods.

[0003] A dental blank (mill blank) is a formed body having a block shape or a disk shape, which is a cut portion made of a dental cutting material that is the material of the dental prosthesis, and a holding portion for attaching it to a cutting machine. As the dental cutting material, various materials such as glass ceramics, zirconia, titanium, and resin are properly used according to the application and characteristics.

[0004] As a resin-based material for dental cutting, a cured product of a curable composition containing an inorganic filler such as silica, a polymerizable monomer such as methacrylate, and a polymerization initiator is generally used and known. However, conventional resin-based materials for dental cutting based on (meth)acrylic resin have limitations in their strength, and there is a need for a material that can also be used for dental prostheses that require high strength, such as molar crowns and bridges.

[0005] In response to such requirements, materials using polyurethane resins having higher strength than (meth)acrylic resins have been proposed. For example, Patent Document 1 describes a polyurethane-based composite material that can be suitably used as a material for cutting processing. By introducing a cross-linked structure formed by the polymerization of radical polymerizable groups inside the polyurethane resin, while taking advantage of the high strength of the polyurethane resin, a polyurethane-based composite material and its manufacturing method that improve the low water resistance, which is its drawback, are described.

[0006] That is, Patent Document 1 describes that "a polyurethane-based composite material manufactured by using a raw material composition containing a diol compound (A2) having one or more radical polymerizable groups; a diisocyanate compound (A1); a polymerizable monomer (B) having one or more radical polymerizable groups in the molecule and not undergoing a polyaddition reaction with either the diol compound (A2) or the diisocyanate compound (A1); a radical polymerization initiator (C); and a filler (D), subjecting A2 and A1 to polyaddition to form a polyurethane component (A) having a molecular weight of 1500 to 5000, and then reacting the radical polymerizable groups contained in (A) with (B) to introduce a cross-linked structure" is uniform throughout, excellent in strength and water resistance, and suitable as a material for dental cutting processing.

[0007] Further, according to Patent Document 1, when reacting the radical polymerizable groups contained in (A) with (B), it is preferable to control the temperature so as not to exceed 150°C, and the 10-hour half-life temperature of the radical polymerization initiator: T 10 A temperature 10°C lower (lower limit temperature L) to T 10 It is particularly preferably carried out in the range of a temperature 25°C higher (upper limit temperature H).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] By the way, when forming the cut portion of a dental blank made of a resin-based material for dental cutting, since it is possible to obtain a molded body of a desired shape at low cost, the curable composition as its raw material is often filled into a resin mold (mold) and polymerized and cured. Therefore, in order to form the cut portion made of the polyurethane-based composite material described in Patent Document 1, according to the method for producing the composite material described in Patent Document 1, a resin matrix containing a raw material composition containing the polyurethane component (A) to the filler (D) was filled into a resin mold and polymerized and cured. As a result, it became clear that whitening appeared on the surface of the obtained polyurethane-based composite material molded body.

[0010] Surface whitening is caused by surface roughness (a large number of fine irregularities are generated on the surface). In order to commercialize the molded body that has become whitened, not only is surface polishing essential, but it is also necessary to increase the polishing amount, so the manufacturing cost increases.

[0011] Therefore, an object of the present invention is to provide a method capable of efficiently manufacturing a polyurethane-based composite material molded body that exhibits the desired cured body physical properties without causing surface whitening of the molded body when obtaining the polyurethane-based composite material molded body by casting polymerization using a resin mold.

Means for Solving the Problems

[0012] The present invention solves the above problems, and a first aspect of the present invention is a method for manufacturing a molded body made of a polyurethane-based composite material in which a filler is dispersed in a matrix made of a polyurethane-based resin having a crosslinked structure, an oligomer having a polyurethane skeleton to which a radically polymerizable group is bonded and having a number average molecular weight of 1500 to 5000, and a glass transition temperature: T GA radical-polymerizable polyurethane component (A) composed of oligomers having a temperature of 35 to 65°C: 100 parts by mass, a non-additive monomer (B) composed of a non-addition-reactive polymerizable monomer having a radical-polymerizable group in the molecule: 5 to 60 parts by mass, a thermal radical polymerization initiator (C) having a 10-hour half-life temperature: T 10 is higher than the above T G by 50°C or more and 125°C or less: 0.01 to 2.0 parts by mass, and an inorganic filler (D): 180 to 550 parts by mass, to prepare a slurry-like or paste-like raw material composition, a raw material composition preparation step, After filling the raw material composition into a resin mold, heating and polymerizing and curing it, a molding step, The heating in the molding step is the above T G is higher than 40°C or more and lower than 10°C than the above T 10 A first heating step of holding for 10 to 168 hours in a temperature range lower than the above T 10 ~ the above T 10 Including a second heating step of holding at a temperature 25°C higher than the above for 5 to 72 hours, A method for producing a polyurethane-based composite material molded body, characterized in that

[0013] In the production method of the above form (hereinafter also referred to as the production method of the present invention), the raw material composition is heated to a temperature higher than 25°C higher than the T of the radical-polymerizable polyurethane component and lower than 10°C lower than the above T G After performing a defoaming treatment, filling into the resin mold is performed while maintaining the temperature, which is preferable. 10

[0014] ​Further, it is preferable that the raw material composition preparation step includes a first raw material composition preparation step of preparing a first raw material composition containing a radically polymerizable diol (A1), a non-polyaddition monomer (B), and an inorganic filler (D), and a polyaddition step of mixing the first raw material composition obtained by this step with a diisocyanate (A2) and subjecting them to a polyaddition reaction to form the radically polymerizable polyurethane component (A), and the raw material composition is prepared by blending a thermal radical polymerization initiator (C) into the first raw material composition, or at the start of or during the polyaddition step, or after the completion of the polyaddition step.

[0015] Furthermore, in the above preferable embodiment, as the radically polymerizable diol (A1), the following general formula (1)

[0016]

Chemical formula

[0017] 〔In the above general formula (1), P is the following structural formula (2)

[0018]

Chemical formula

[0019] {In the above general formula (2), R 1 is a hydrogen atom or a methyl group, and X 2 is 0 or 1.} is any divalent group represented by, X 1 are each independently 0 or 1, Y is 1 or 2, and when both X 1 are 0, Y is 2.〕 the compound represented by is used, and as the diisocyanate (A2), the following general formula (3)

[0020]

Chemical formula

[0021] {In the general formula (3), A is represented by the following structural formula (4):

[0022]

Chemical formula

[0023] {In the general formula (4), each R 3 is independently a hydrogen atom or a methyl group.} is any divalent group represented by the formula.} Using the compound represented by As the non-additive monomer (B), the following general formula (5):

[0024]

Chemical formula

[0025] {In the general formula (5), each R 4 is independently a hydrogen atom or a methyl group, and Z 1 is an integer from 1 to 10.} It is preferable to use the compound represented by

Advantages of the Invention

[0026] According to the present invention, it becomes possible to efficiently produce a polyurethane-based composite material molded body that is uniform, excellent in strength, water resistance, and aesthetics, and is preferably used as a dental cutting material.

Modes for Carrying Out the Invention

[0027] 1. Outline of the manufacturing method of the present invention The present inventors conducted studies to solve the above problems. Specifically, when obtaining a molded body by casting polymerization using a resin mold from the raw material composition disclosed in Patent Document 1, the temperature was raised in multiple stages and the temperature increase pattern was variously changed. As a result, although it was possible to suppress the whitening of the molded body in some cases, it was found that the flexural strength of the molded body might decrease in the system where the whitening was suppressed.

[0028] In view of the above results, the inventors considered that the cause of whitening was that there were fine voids between the raw material composition and the resin mold during filling, or peeling or rubbing between the raw material composition (during curing) and the surface of the resin mold due to polymerization shrinkage occurring during the first-stage heating. They thought that if this could be suppressed and sufficient curing could be carried out in the subsequent stage, the above problems could be solved, and thus they conducted studies. Specifically, regarding the heating conditions in the first stage, the glass transition temperature of the polyurethane component (A): T G and the 10-hour half-life temperature of the thermal radical polymerization initiator (C): T 10 were focused on. The fluidity of the raw material composition was increased to spread it to every corner of the resin mold, and the holding temperature and holding time were studied such that a very gentle and uniform polymerization reaction occurred, allowing the resin mold to deform following the shrinkage associated with polymerization during heating (heat retention). As a result, for those in which the T G of the polyurethane component (A) was within a certain range, after holding at a temperature slightly higher than T G and significantly lower than T 10 for a certain time in the first-stage heating and then holding at a temperature and time such that polymerization curing proceeded sufficiently in the second-stage heating, it was found that the above problems could be solved, and the present invention was thus completed.

[0029] Thus, the manufacturing method of the present invention is an improvement on the method described in Patent Document 1 as a method for manufacturing a molded body made of a polyurethane-based composite material in which a filler is dispersed in a matrix made of a polyurethane-based resin having a crosslinked structure. Similar to that method, it includes a raw material composition preparation step of preparing a slurry-like or paste-like raw material composition (corresponding to the second raw material composition in Patent Document 1), and a molding step of filling the raw material composition into a mold and then heating it to cause polymerization curing. And (1) the composition of the raw material composition is specified, (2) the glass transition temperature of the radically polymerizable polyurethane component (A): T G and the 10-hour half-life temperature of the thermal radical polymerization initiator (C): T 10The points that have been specified, (3) using a resin formwork, and (4) the heating conditions during polymerization and curing being specified are regarded as major characteristic points. Therefore, except for these points, there are no significant differences from the manufacturing method described in Patent Document 1. Including these unchanged points, the following will explain in detail each step of the manufacturing method of the present invention, etc.

[0030] In the present specification, unless otherwise specified, the notation "x to y" using numerical values x and y means "x or more and y or less". In such a notation, when only the numerical value y is provided with a unit, the said unit shall also apply to the numerical value x. Further, in the present specification, the term "(meth)acrylic" means both "acrylic" and "methacrylic".

[0031] 2. Regarding the raw material composition preparation step In the raw material composition preparation step, an oligomer having a polyurethane skeleton to which a radically polymerizable group is bonded, with a number average molecular weight of 1500 to 5000, and a glass transition temperature: T G A radically polymerizable polyurethane component (A) composed of an oligomer with a temperature of 35 to 65 °C: 100 parts by mass, a non-additive monomer (B) composed of a non-addition-reactive polymerizable monomer having a radically polymerizable group in the molecule: 5 to 60 parts by mass, a thermal radical polymerization initiator (C) with a half-life temperature of 10 hours: T 10 being 50 °C or higher and 125 °C or lower than the said T G 0.01 to 2.0 parts by mass, and an inorganic filler (D): 180 to 550 parts by mass are included to prepare a slurry-like or paste-like raw material composition.

[0032] The raw material composition used in the production method of the present invention corresponds to the second raw material composition described in Patent Document 1. Similar to the method described in Patent Document 1, a radical polymerizable diol (A1) which is one of the raw materials of the polyurethane component (A), a non-addition monomer (B), and an inorganic filler (D) are included, and further a step of preparing a first raw material composition which may contain a thermal radical polymerization initiator (C) (also referred to as the "first raw material composition preparation step") is carried out. After that, the obtained first raw material composition, a diisocyanate (A2) which is the other raw material of the radical polymerizable polyurethane component (A), are mixed and subjected to an addition polymerization reaction to form a radical polymerizable polyurethane component (A) (also referred to as the "addition polymerization step"). It can be preferably adjusted by carrying out the step. When the thermal radical polymerization initiator (C) is not blended in the first raw material composition, it may be blended simultaneously with the blending of the diisocyanate (A2) or after the formation of the radical polymerizable polyurethane component (A).

[0033] Since the radical polymerizable diol (A1) and the diisocyanate (A2) undergo a quantitative addition polymerization reaction to produce the radical polymerizable polyurethane component (A), the total molar number of hydroxyl groups possessed by the radical polymerizable diol (A1): T OH to the total molar number of isocyanate groups possessed by the diisocyanate (A2): T NCO ratio: T NCO / T OH is such that T NCO / T OH is in the range of 0.9 to 1.1, preferably in the range of 1.0 to 1.05. The above T NCO / T OHWhen it slightly deviates from 1, unreacted radically polymerizable diol (A1) or diisocyanate (A2) will remain, but it is acceptable within the above range. The polyaddition reaction is preferably carried out in the coexistence of 0.01 to 0.10 mol of radically polymerizable monool (A3) with respect to 1 mol of radically polymerizable diol (A1). When mixing the radically polymerizable monool (A3), it is preferable to mix the radically polymerizable monool (A3) with the primary raw material composition before mixing the diisocyanate (A2) or simultaneously with the mixing of the diisocyanate (A2) so that the radically polymerizable monool (A3) does not come into direct contact with the diisocyanate (A2).

[0034] The polyaddition reaction is initiated by heating simultaneously with or after the mixing of the primary raw material composition and the diisocyanate (A2) as needed, and is carried out until at least one of the radically polymerizable diol (A1) {or radically polymerizable diol (A1) and radically polymerizable monool (A3)} and the diisocyanate (A2) is substantially consumed by the polyaddition reaction. Therefore, the amount of the polyurethane component (A) contained in the raw material composition can be determined by calculation from the compounding amounts of (A1) {or radically polymerizable diol (A1) and radically polymerizable monool (A3)} and the diisocyanate (A2). And the compounding amounts of the respective components in the raw material composition preparation step are defined based on the amount of the polyurethane component (A) thus determined.

[0035] Also, the number average molecular weight of the radically polymerizable polyurethane component (A) contained in the raw material composition can be confirmed by isolating and analyzing the polyurethane component (A) from a part sampled from the raw material composition prepared in the raw material composition preparation step or from a raw material composition separately prepared under the same conditions.

[0036] The number average molecular weight of the radically polymerizable polyurethane component (A) means the number average molecular weight in terms of polystyrene determined by GPC (gel permeation chromatography) measurement. The number average molecular weight of the radically polymerizable polyurethane component (A) in the raw material composition can be determined by adding a solvent such as THF (tetrahydrofuran) or dimethyl sulfoxide (DMSO) to the radically polymerizable raw material composition as needed, removing insoluble components such as the inorganic filler (D) by operations such as filtration and centrifugation, and performing GPC measurement on the resulting solution or the solution with additional solvent added as needed. From the perspective of achieving a good balance between the fluidity of the raw material composition and the strength of the resulting polyurethane-based composite material, the above number average molecular weight is preferably 1500 to 3500, and more preferably 2000 to 3000.

[0037] Further, the glass transition temperature of the radically polymerizable polyurethane component (A): T G can be confirmed as follows using the polyurethane component (A) isolated from the raw material composition separately prepared under the same conditions, or the polyurethane component obtained by reacting only the radically polymerizable diol (A1) and diisocyanate (A2) under the same polyaddition conditions. That is, for the above polyurethane component (A), when the temperature is raised from 20°C to 90°C at a heating rate of 20°C / min under a nitrogen atmosphere to obtain a DSC curve, the DSC hardly changes and remains constant as the temperature rises, but a "step-shaped baseline shift" is observed where it gradually decreases and then becomes constant again when a certain temperature is reached. The glass transition point can be determined as the "temperature at the start of the gradual decrease", that is, the temperature corresponding to the intersection of the straight line obtained by extending the low-temperature side baseline before the shift and the inclined line of the step-shaped change part. T G needs to be 35 to 65°C, and when T G is lower than 35°C, a polyurethane-based composite material molded body with excellent strength cannot be obtained. Also, when T GWhen it is higher than 65°C, it is very difficult to achieve both suppression of whitening and strength. Note that the polyurethane component (A) obtained by the method as described above is used as the measurement sample because when the polymerizable monomer coexists, the sample flows during heating and the glass transition temperature cannot be observed.

[0038] Hereinafter, various raw materials used, the primary raw material composition preparation process, the polyaddition process, etc. will be described.

[0039] <Radical polymerizable diol (A1)> The radical polymerizable diol (A1) is a compound that serves as a raw material for forming the radical polymerizable polyurethane component (A), and has at least one radical polymerizable group in the molecule, specifically, a radical polymerizable carbon-carbon double bond such as a vinyl group, a (meth) acrylate group, and a styryl group, and a compound having two hydroxyl groups. Then, the two hydroxyl groups (-OH groups) possessed by the radical polymerizable diol (A1) and the two isocyanate groups of the diisocyanate (A2) undergo a polyaddition reaction to form the main chain portion of the radical polymerizable polyurethane component (A).

[0040] As the radical polymerizable diol (A1), the compounds that can be used in Patent Document 1 can be used without particular limitation, but it is easy to control the number average molecular weight of the radical polymerizable polyurethane component (A) to 1500 to 5000, and also, T G Since it is likely to be in the range of 35 to 65°C, it is preferable to use the compound represented by the following general formula (1).

[0041]

Chemical formula

[0042] In the above general formula (1), P is any divalent group represented by the following structural formula (2), and X 1 is each independently 0 or 1, Y is 1 or 2, and when both X 1 are 0, Y is 2.

[0043]

Chem.

[0044] Also, in the above general formula (2), R 1 is a hydrogen atom or a methyl group, and X 2 is 0 or 1.

[0045] Specific examples of the compound represented by the above general formula that can be preferably used as the radically polymerizable diol (A1) in the present invention include trimethylolpropane mono(meth)acrylate, glycerol mono(meth)acrylate, erythritol di(meth)acrylate, pentaerythritol di(meth)acrylate, and the like. These can be used alone or in combination of different types.

[0046] <Diisocyanate (A2)> Diisocyanate (A2) is a compound having two isocyanate groups (-N=C=O groups) in one molecule, and forms a radically polymerizable polyurethane component (A) by polyaddition with the above-described radically polymerizable diol (A1). As for diisocyanate (A2), compounds that can be used in Patent Document 1 can be used without particular limitation, but it is easy to control the number average molecular weight of the radically polymerizable polyurethane component (A) to 1500 to 5000, and T G is likely to be in the range of 35 to 65°C. Further, from the viewpoints of the fluidity of the obtained raw material composition and the strength of the obtained polyurethane-based composite material, it is preferable to use a compound represented by the following general formula (3) having a phenyl group in the molecule.

[0047]

Chem.

[0048] In the above general formula (3), A is any divalent group represented by the following structural formula (4).

[0049]

Chem.

[0050] Also, in the above general formula (4), R 3 is independently a hydrogen atom or a methyl group, respectively.

[0051] Specific examples of the compound represented by the above general formula that can be preferably used as the diisocyanate (A2) in the present invention include 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, 4,4'-methylenediphenyl diisocyanate, 3,3'-dichloro-4,4'-diisocyanatobiphenyl, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, 1,5-diisocyanatonaphthalene, 1,3-phenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, m-xylylene diisocyanate, and the like.

[0052] <Radical polymerizable monoalcohol (A3)> The radical polymerizable monoalcohol (A3) is a compound having at least one radical polymerizable group and one hydroxyl group in the molecule, and forms the terminal portion of the radical polymerizable polyurethane component (A) by coexisting during the polyaddition. Compounds that can be used in Patent Document 1 for the radical polymerizable monoalcohol (A3) can be used without particular limitation. For example, ethylene glycol (meth)acrylate, pentaerythritol tri(meth)acrylate, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid, etc. can be preferably used. The radical polymerizable monoalcohol (A2) may be used alone or in combination of two or more. It is preferable to use the radical polymerizable monoalcohol (A3) in an amount of 0.01 to 0.10 mol, particularly 0.02 to 0.06 mol, per 1 mol of the radical polymerizable diol (A1).

[0053] <Non-polyadditive monomer (B)> The non-additive monomer (B) is a compound having at least one radically polymerizable group in the molecule and not undergoing an addition polymerization reaction with either the radically polymerizable diol (A1) or the diisocyanate (A2). That is, it does not have any of the hydroxyl group, amino group, carboxyl group, isocyanate group, epoxy group, and mercapto group in the molecule.

[0054] From the viewpoint of ease of forming crosslinks, the number of radically polymerizable groups contained in the molecule is preferably 2 to 6, more preferably 2 to 4. By setting the number of radically polymerizable groups to 2 or more, the crosslink density can be increased, making it easier to obtain a cured body having sufficient strength. Also, by setting the number of radically polymerizable groups to 6 or less, it becomes easier to suppress shrinkage during curing. Further, the non-additive monomer (B) is preferably a liquid at room temperature (i.e., 25 °C).

[0055] The non-additive monomer (B) preferably has a viscosity in the range of 1 mPa·s to 1000 mPa·s, particularly in the range of 1 mPa·s to 100 mPa·s, at room temperature.

[0056] As the non-additive monomer (B), the compounds that can be used in Patent Document 1 can be used without particular limitation, but from the viewpoint of easy dispersion of the polyurethane component (A), it is preferable to use the compound represented by the following general formula (5).

[0057]

Chemical formula

[0058] In the above general formula (5), R 4 are each independently a hydrogen atom or a methyl group, and Z 1 is an integer from 1 to 10, preferably an integer from 1 to 3.

[0059] Examples of compounds that can be particularly preferably used as the non-additive monomer (B) include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, and triethylene glycol di(meth)acrylate.

[0060] The blending amount of the non-additive monomer (B) is 5 to 60 parts by mass with respect to 100 parts by mass of the polyurethane component (A). When the blending amount exceeds the upper limit value, it tends to be very difficult to obtain a polyurethane-based composite material having high strength. When it is below the lower limit value, it tends to be very difficult to obtain a polyurethane-based composite material into which a uniform crosslinked structure is introduced. For the reason of being easy to obtain a polyurethane-based composite material having high strength and a uniform crosslinked structure introduced, the above blending amount is preferably 8 to 55 parts by mass, particularly 11 to 45 parts by mass.

[0061] <Thermal radical polymerization initiator (C)> The thermal radical polymerization initiator (C) has a function of initiating a radical polymerization reaction in the molding process, and by reacting and bonding the radical polymerizable groups of the radical polymerizable polyurethane component (A) and the radical polymerizable groups of the radical polymerizable monomer (B), the raw material composition is polymerized and cured, and crosslinking points are formed in the polyurethane-based resin that becomes the matrix. As the production method of the present invention, as the thermal radical polymerization initiator (C), its 10-hour half-life temperature: T 10 is 50°C or higher and 125°C or lower than the glass transition temperature: T G of the radical polymerizable polyurethane component (A). That is, when T G is 35°C which is the lower limit value, those with T 10 of 85°C to 125°C are used. When T G is 65°C which is the upper limit value, those with T 10 of 115°C to 125°C are used. Here, the 10-hour half-life temperature: T 10 refers to the temperature at which the amount of the thermal polymerization initiator decreases to half of the initial amount after 10 hours from the initial stage, and is used as an index representing the reactivity of the thermal polymerization initiator.

[0062] Specific examples of the thermoradical polymerization initiator (C) that can be suitably used include peroxide initiators such as t-butyl peroxy laurate (T 10 = 98 °C) and t-butyl cumyl peroxide (T 10 = 120 °C), dicumyl peroxide (T 10 = 116 °C), etc., and azo initiators such as 2,2'-azobis(N-butyl-2-methylpropionamide) (T 10 = 110 °C) and 2,2'-azobis(2,4,4-trimethylpentane) (T 10 = 110 °C). These thermopolymerization initiators may be used alone or in combination of two or more.

[0063] Note that the blending amount of the thermoradical polymerization initiator (C) is 0.01 to 2.0 parts by mass, preferably 0.1 to 1.0 parts by mass, based on 100 parts by mass of the polyurethane component (A).

[0064] <Inorganic filler (D)> The inorganic filler (D) is dispersed in the polyurethane-based resin matrix and complexed with the polyurethane-based resin matrix, thereby having the function of improving physical properties such as the mechanical strength, wear resistance, and water resistance of the polyurethane-based composite material.

[0065] As the inorganic filler (D), a powder material composed of particles made of inorganic substances such as silica, alumina, titania, zirconia, or their composite oxides, glass, etc. is used. Specific examples of such inorganic fillers include powder materials composed of spherical particles made of amorphous silica, silica-zirconia, silica-titania, silica-titania-zirconia, quartz, alumina, etc., and powder materials composed of irregularly shaped particles. When the polyurethane-based composite material produced by the production method of the present invention is used as a dental material, as the inorganic filler (D), those made of silica, titania, zirconia, or their composite oxides are preferably used, and silica or its composite oxide is particularly preferred. This is because inorganic fillers made of these materials have no risk of dissolution in the oral environment, the refractive index difference from the polyurethane resin-based matrix is easy to adjust, and transparency and aesthetics are easy to control.

[0066] The shape of the particles constituting the powder material serving as the inorganic filler (D) is not particularly limited and can be appropriately selected according to the intended use of the polyurethane-based composite material. For example, from the viewpoint of obtaining a polyurethane-based composite material particularly excellent in abrasion resistance, surface lubricity, and gloss persistence, it is preferably (substantially) spherical.

[0067] The average particle diameter of the powder material serving as the inorganic filler (D) is preferably 0.001 μm to 100 μm, more preferably 0.01 μm to 10 μm, from the viewpoints of abrasion resistance, surface lubricity, and gloss persistence. Also, from the viewpoint of easily improving the content rate of the inorganic filler (D) in the polyurethane-based composite material, it is preferable to use a plurality of powder materials having different average particle diameters. Specifically, it is preferable to combine a powder material having an average particle diameter of 0.001 μm to 0.1 μm and a powder material having an average particle diameter of 0.1 μm to 100 μm, and more preferably to combine a powder material having an average particle diameter of 0.01 μm to 0.1 μm and a powder material having an average particle diameter of 0.1 μm to 10 μm.

[0068] The above average particle size means the average particle size determined by image analysis using a scanning electron microscope (SEM) image. When observing a powder sample with an SEM at a magnification of 5000 - 100000 times so that 100 or more spherical particles whose overall shape can be confirmed are included in the field of view, based on the image (or photograph) obtained, the maximum diameter (nm) of each of 30 or more arbitrarily selected particles is measured, and the value obtained by dividing the sum thereof by the number: n (a natural number ≧ 30) is meant. That is, the maximum diameter of each particle is represented by x i (where i is a natural number from 1 to n.) and when the average particle size is represented by x AV , x AV =(Σx i ) / n means the value defined thereby.

[0069] It is preferable to use the inorganic filler (D) that has been surface-treated in order to improve the compatibility with the polyurethane-based resin matrix and improve the mechanical strength and water resistance of the polyurethane-based composite material.

[0070] The compounding amount of the inorganic filler (D) is 180 - 550 parts by mass with respect to 100 parts by mass of the polyurethane component (A). When the compounding amount exceeds the upper limit value, it tends to be very difficult to obtain a polyurethane-based composite material molded body having high strength, and when it is below the lower limit value, it tends to be very difficult to obtain a uniform crosslinked structure-introduced polyurethane-based composite material. The above compounding amount is preferably 200 - 500 parts by mass, particularly 250 - 450 parts by mass.

[0071] <Other Additives> In addition to the essential components described above, various other additives may be blended in the primary raw material composition or the raw material composition. Examples of various additives include polymerization inhibitors, fluorescent agents, ultraviolet absorbers, antioxidants, pigments, antibacterial materials, X-ray contrast agents, etc., and the addition amount thereof may be appropriately determined according to the desired purpose.

[0072] <Primary Raw Material Composition Preparation Step> The preparation of the primary raw material composition may be carried out by mixing all the components constituting the primary raw material composition at once, or after preparing a mixture by mixing some of the components constituting the primary raw material composition, adding and mixing the remaining components constituting the primary raw material composition. At this time, the mixing method when mixing each component is not particularly limited, and methods using a magnetic stirrer, a Lycra machine, a planetary mixer, a trimix, a centrifugal mixer, etc. are appropriately used. Further, for the reason that it is easy to uniformly disperse the inorganic filler (D), a radical polymerizable diol (A1), a radical polymerizable monoalcohol (A3) used as necessary, and a non-additive monomer (B) are first mixed to prepare a mixed composition, and then the inorganic filler (D) is added to and mixed with this mixed composition to prepare the primary raw material composition. Furthermore, from the viewpoints of being easy to suppress side reactions and easy to disperse, it is preferable to add other additives to the primary raw material composition. Also, from the viewpoint of operability, mixing is preferably carried out under normal pressure conditions or pressurized conditions. The primary raw material composition thus prepared is preferably subjected to a defoaming treatment to remove the bubbles contained therein. As the defoaming method, a known method carried out under normal pressure conditions or pressurized conditions is used, and methods such as pressure defoaming and centrifugal defoaming can be arbitrarily used.

[0073] In addition, the primary raw material composition may further contain, as other additives, a catalyst for promoting the polyaddition reaction, if necessary. Examples of the catalyst for promoting the polyaddition reaction include tin octylate and dibutyltin diacetate.

[0074] <Polyaddition step> In the double addition process, a primary raw material composition and diisocyanate (A2) are mixed, and after mixing, heating is performed as necessary. The reaction time varies depending on the reaction temperature. For example, when the reaction temperature is 30°C or higher and less than 50°C, 60 hours or more is preferable, and 72 hours or more is more preferable. When the heating temperature is 50°C or higher and less than 80°C, 24 hours or more is preferable, and 36 hours or more is more preferable. When the heating temperature is 80°C or higher, 15 hours or more is preferable, and 24 hours or more is more preferable. In any of these cases, the upper limit of the heating time is not particularly limited, but from a practical perspective such as productivity, it is preferably 120 hours or less. The mixing in the double addition process is preferably carried out under normal pressure conditions or pressurized conditions using various mixing devices, similar to the mixing in the primary raw material composition preparation process.

[0075] Regarding (A1), (A2), and (A3), as described above, although in small amounts, a part may remain unreacted, and the content (parts by mass) of each of the above components contained in the raw material composition is, respectively, Content of the radically polymerizable polyurethane component (A): [A], Content of the non-double addition monomer (B): [B], Content of the radically polymerizable diol (A1): [A1], Content of the diisocyanate (A2): [A2] Content of the radically polymerizable monoalcohol (A3): [A3], When represented in this way, the total mass of these is consistent with the total mass of the raw materials (A1), (A2), (A3), and (B) represented in terms of the above raw material base amount.

[0076] 3. Regarding the molding process In the forming process, the radical polymerizable polyurethane component (A) is crosslinked by heating the raw material composition to perform radical polymerization, thereby obtaining the polyurethane-based composite material. Since it is possible to obtain a polyurethane-based composite material molded body having a desired shape at low cost and the effect of suppressing whitening under the heating conditions of the present invention is remarkable, after filling the raw material composition into a resin mold (mold), the above radical polymerization is carried out. The type of resin is not particularly limited as long as it can withstand the temperature and pressure during radical polymerization. Thermoplastic resins such as polypropylene, polyacetal, polytetrafluoroethylene, and polycarbonate, thermosetting resins such as polyimide, polyamide, phenol, and melamine resin, and various engineering plastics such as PEEK, PTFE, PEK, and PEKK are used. Considering the price, ease of handling during molding, and ease of following when the raw material composition cures, it is preferably a general-purpose thermoplastic resin such as polypropylene or high-density polyethylene. The thickness of the resin mold (mold) is preferably 0.5 to 20 mm, more preferably 1 mm to 5 mm. If the thickness is thinner than the above range, the mold will be deformed when the secondary raw material composition is filled, so it is difficult to obtain a cured body having the same shape. Also, if it is thick, it is difficult to suppress whitening because the mold does not follow. These resins can be appropriately selected according to the handling during production, the ease of pouring the fluid paste, etc.

[0077] When filling the raw material composition into a resin mold (mold), the raw material composition is at a predetermined temperature, specifically, 25 °C higher than the T of the radical polymerizable polyurethane component G or higher and the 10-hour half-life temperature of the thermal radical polymerization initiator (C): T 10By heating to a temperature equal to or lower than a temperature 10°C lower than that, shaping its properties into a uniform fluid paste and then shaping it into a predetermined shape, and performing radical polymerization while maintaining uniformity, it is possible to efficiently obtain a molded body made of a polyurethane-based composite material with a uniform crosslinked structure introduced. From the perspective of being able to change to a paste state more uniformly, the temperature (heating temperature) at which the raw material composition is held before filling a resin mold (mold) is the glass transition temperature: T of the radically polymerizable polyurethane component (A). G more than 30°C higher than, ~T 10 and preferably 15°C lower than that.

[0078] As a method of maintaining the temperature (heating temperature) at which the raw material composition is held before filling a resin mold (mold), in order to avoid local high temperatures, a method of placing the container holding the raw material composition in an atmosphere maintained at a predetermined temperature, a method of contacting it with a heat medium (such as a liquid or a plate) maintained at a predetermined temperature, etc. are preferred. By maintaining the temperature as described above, the raw material composition becomes uniform even without operations such as stirring. However, a stirring operation may be performed to ensure that no bubbles or the like remain inside.

[0079] As the heating temperature during curing by radical polymerization, it is 40°C higher than the T of the radically polymerizable polyurethane component and at a temperature equal to or lower than a temperature 10°C lower than the 10-hour half-life temperature: T of the thermal radical polymerization initiator (C). G After holding for 10 to 168 hours at a temperature equal to or lower than a temperature 10°C lower than that, the 10-hour half-life temperature T of the initiator (C). 10 ~ the T 10 ~ the T 10 Radical polymerization is carried out under at least two-stage conditions of holding for 5 to 72 hours at a temperature more than 25°C higher than that.

[0080] When heating within the heating temperature range of the first stage, if the holding time is shorter than 10 hours, radical polymerization sufficient to suppress whitening does not proceed, and the appearance of the obtained polyurethane-based composite material molded body whitens. Also, if the holding time is longer than 168 hours, not only does productivity decrease, but unexpected coloring of the cured body is caused.

[0081] Also, when heating within the heating temperature range of the second stage, if the holding time is shorter than 5 hours, radical polymerization necessary for sufficient curing does not proceed, and the strength and water resistance of the obtained polyurethane-based composite material molded body deteriorate. Also, if the holding time is longer than 72 hours, not only does productivity decrease, but unexpected coloring of the cured body is caused.

[0082] Although the mechanism by which the appearance whitening of the obtained polyurethane-based composite material molded body can be suppressed while maintaining high strength and water resistance is not necessarily clear, by heating within the heating temperature range of the first stage, the progress of radical polymerization becomes gentle, and the resin mold (mold) can be uniformly deformed following the polymerization shrinkage. Also, by heating in the subsequent heating temperature range of the second stage, it is considered that the crosslinking reaction proceeds uniformly in a state where the polyurethane has sufficient fluidity at the initial stage of radical polymerization.

[0083] In addition, under the above heating conditions, it is not necessarily required to keep the temperature constant during the holding time. Rather, it is preferable to have a gradient such that the temperature gradually increases at the initial stage. Heating with such a temperature increase pattern can appropriately set a program that raises the temperature at a constant speed until a predetermined temperature is reached and then holds it, or a program that sets the initial temperature and the final temperature and performs gradient control therebetween. These programs can also include a temperature decrease process within a predetermined temperature range. Furthermore, for each step, these control methods can be used singly or in combination as a program.

[0084] In addition, in the radical polymerization by heating described above, in order to suppress the formation of voids caused by bubbles in the cured body, it is preferable to pressurize the second raw material composition during the radical polymerization. There is no limitation on the method of pressurization, and it may be mechanically pressurized or pressurized with a gas such as nitrogen. By performing radical polymerization in this way, a molded body made of a polyurethane-based composite material in which the filler (D) is dispersed in a polyurethane-based resin matrix can be obtained.

[0085] 4. Application Example of the Manufacturing Method of the Present Invention (Manufacture of Dental Milling Materials) The polyurethane-based composite material of the present invention has high water resistance while maintaining high strength even in a hydrophilic environment such as in the oral cavity. Because of having such high water resistance, the manufacturing method of the present invention can be suitably used as a manufacturing method of the dental milling material, particularly when producing a dental prosthesis by milling a dental milling material using a dental CAD / CAM system.

Examples

[0086] Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited only to these examples.

[0087] The components used in each example and comparative example and their abbreviations are shown below. (1) Radical Polymerizable Diol (A1) GLM: Glycerol Monomethacrylate Bis-GMA: Bisphenol A Glycidyl Methacrylate (2) Diisocyanate (A2) XDI: m-Xylylene Diisocyanate TDI: Toluene-2,4-Diisocyanate HDI: Hexamethylene Diisocyanate (3) Radical Polymerizable Monoalcohol (A3) HEMA: Ethylene Glycol Monomethacrylate (4) Non-Additive Monomer (B) TEGDMA: Triethylene glycol dimethacrylate (5) Thermal radical polymerization initiator (C) PBL: t-Butyl peroxy laurate (10-hour half-life temperature 98 °C) PBC: t-Butyl cumyl peroxide (10-hour half-life temperature 120 °C) DPO: Dicumyl peroxide (10-hour half-life temperature 116 °C).

[0088] (6) Inorganic filler (D) F1: Silica-zirconia (average particle size: 0.4 μm, surface-treated with 3-(trimethoxysilyl)propyl methacrylate) F2: Silica-titania (average particle size: 0.08 μm, surface-treated with 3-(trimethoxysilyl)propyl methacrylate) Examples of the production method of the present invention are shown below together with comparative examples.

[0089] Example 1 (1) Raw material composition preparation step (1-1) Primary raw material composition preparation step First, a mixed composition was prepared by mixing GLM (10.4 parts by mass), which is a radical polymerizable diol (A1), TEGDMA (5.7 parts by mass), which is a non-additive monomer (B), and PBC (0.1 part by mass), which is a thermal radical polymerization initiator (C). Next, F1 (50.4 parts by mass) and F2 (21.6 parts by mass), which are inorganic fillers (D), were added to this mixture composition and kneaded to prepare a primary raw material composition. The above operations were carried out at normal temperature (25 °C) environment.

[0090] (1-2) Polyaddition step At normal temperature (25 °C) environment, XDI (1.24 g), which is a diisocyanate (A2), was added to a rotation revolution mixer containing the obtained primary raw material composition (9.0 g) and kneaded, and then left standing in an incubator at 60 °C for 24 hours to carry out a polyaddition reaction to form a radical polymerizable polyurethane component (A) and prepare a raw material composition (hereinafter, also referred to as "secondary raw material composition"). Table 1 summarizes the parameters regarding each raw material (abbreviation), usage amount (numbers in parentheses: unit is parts by mass), and composition used in the primary raw material composition preparation process and the polyaddition process. In Table 1, "radical polymerizability" is abbreviated as "polymerizability", and "↑" in the table means "the same as above".

[0091] (2) Evaluation of the secondary raw material composition (2-1) Evaluation of the number average molecular weight of the radical polymerizable polyurethane component (A) Regarding the obtained secondary raw material composition, the number average molecular weight of the radical polymerizable polyurethane component (A) was evaluated as follows. That is, 1 g of the obtained secondary raw material composition was weighed into a screw tube bottle, 3.5 ml of DMSO was added and stirred, and the obtained DMSO solution was centrifuged at 10,000 rpm for 10 minutes using a centrifuge (manufactured by AS ONE Corporation). Next, the supernatant obtained by centrifugation was filtered through a membrane filter (PORE SIZE 20μm, manufactured by ADVANTEC Co., Ltd.) to obtain a filtrate. Then, regarding this filtrate, GPC measurement was performed under the GPC measurement conditions shown below to determine the number average molecular weight in terms of polystyrene of the radical polymerizable polyurethane component (A) obtained by the polyaddition reaction. As a result, the number average molecular weight was 3200.

[0092] [GPC measurement conditions] Measuring device: Advanced Polymer Chromatography (manufactured by Waters Japan) · Column: ACQUITY APC™ XT45 1.7μm ACQUITY APC™ XT125 2.5μm · Column temperature: 40°C · Developing solvent: THF (flow rate: 0.5 ml / min) · Detector: Photodiode array detector 254nm (PDA detector).

[0093] (2-2) Evaluation of the glass transition point of the radical polymerizable polyurethane component (A) Separately, the glass transition point of the polyurethane component (A) obtained by subjecting a radically polymerizable diol (A1) and a diisocyanate (A2) to a polyaddition reaction at the same quantitative ratio as in Example 1 was evaluated as follows. That is, using DSC8230 (manufactured by Rigaku), the "gradual decrease start temperature" of the "stepwise baseline shift" in the DSC curve obtained by raising the temperature from 20°C to 90°C at a rate of 20°C / min under a nitrogen atmosphere (the temperature corresponding to the intersection of the straight line obtained by extending the low-temperature side baseline before the shift and the inclined line of the stepwise change portion) was defined as the glass transition point: T G When evaluated as G it was 46°C.

[0094] (3) Molding process The obtained secondary raw material composition was degassed under vacuum at 80°C, and then injected into a polypropylene mold (length 18.5 mm × width 22 mm × height 17 mm (thickness 1.7 mm)). After heating at 100°C for 15 hours under nitrogen pressure (0.3 MPa), radical polymerization was carried out under the temperature conditions of heating at 120°C for 18 hours, thereby obtaining a polyurethane-based composite material in which a filler was dispersed in a polyurethane-based resin matrix. The results are summarized in Table 2. In Table 2, "radical polymerization" is abbreviated as "polymerization", and the two-step heating temperature conditions for radical polymerization are described separately as polymerization temperature condition 1 and polymerization temperature condition 2. Also, T 10 is the 10-hour half-life of the thermal radical polymerization initiator (C), T1 and T2 are the heating temperatures of polymerization temperature conditions 1 and 2, respectively, and T G represents the glass transition point. Note that "↑" in the table means "the same as above".

[0095] (4) Evaluation of the polyurethane-based composite material (cured body) For the obtained polyurethane-based composite material, the flexural strength, flexural strength in water, and retention rate (water resistance) were evaluated. The evaluation methods and results are shown below.

[0096] [Flexural strength BS d ​A polyurethane-based composite material (cured body) obtained using a mold (vertical 18.5 mm × horizontal 22 mm × height 17 mm (thickness 1.7 mm)) was cut out with a low-speed diamond cutter (manufactured by Buehler), and then polished using #2000 waterproof abrasive paper to produce five prismatic test pieces (thickness: approximately 1.2 mm × width: approximately 4.0 mm × length: 14.0 mm). Next, a three-point bending test was performed on each test piece using an autograph (manufactured by Shimadzu Corporation), and the bending load at the maximum point was measured. The bending strength (MPa): BS is calculated from the bending load at the maximum point (N): P, the distance between the supports: S, the width of the test piece (measured value, mm): W, and the thickness of the test piece (measured value, mm): B using the following formula: BS = 3PS / 2WB 2 Based on this, the bending strength BS was determined. The bending load at the maximum point was measured with the distance between the supports set to 12.0 mm and the crosshead speed set to 1.0 mm / min. As a result, the average value of the bending strength BS of the five test pieces (bending strength BS d ) was 298 MPa.

[0097] [Bending strength in water BS W [Bending strength] Five test pieces were prepared in the same manner as described in the column. All the test pieces were stored in ion-exchanged water at 37°C for one week. After that, for the test pieces taken out from the ion-exchanged water, after removing the moisture adhering to the surface, a three-point bending test was performed under the same test conditions as described in the column of [Bending strength], and the bending load at the maximum point of the test pieces after storage in water was measured. Then, the bending strength BS was determined for each of the test pieces after storage in water based on the above formula. As a result, the average value of the bending strength BS of the five test pieces after storage in water (bending strength in water BS w ) was 278 MPa.

[0098] [Retention rate (water resistance)] The retention rate, which is an index indicating the water resistance of the cured body, is calculated using the following formula: Retention rate (%) = 100 × BS W / BS d Based on this, it was calculated. In this example, the retention rate was 93%, confirming that it has high water resistance.​

[0099] Comparative Example 1 A polyurethane-based composite material was produced in the same manner as in Example 1, except that the secondary raw material composition prepared in Example 1 was used and the heating conditions (Temperature Condition 1 and Temperature Condition 2) in the molding process were changed as shown in Table 2, and the secondary raw material composition and the polyurethane-based composite material were evaluated. The results are shown in Table 3.

[0100] Examples 2 to 4, Comparative Example 2 A polyurethane-based composite material was produced in the same manner as in Example 1, except that HEMA, which is a radically polymerizable monool (A3), was blended, the respective raw materials and their amounts used were changed as shown in Table 1, and the heating conditions (Temperature Condition 1 and Temperature Condition 2) in the molding process were changed as shown in Table 2, and the secondary raw material composition and the polyurethane-based composite material were evaluated. The results are shown in Table 3.

[0101] Example 5 A polyurethane-based composite material was produced in the same manner as in Example 1, except that a part of GLM, which is a radically polymerizable diol (A1), was changed to Bis-GMA, the respective raw materials and their amounts used were changed as shown in Table 1, and the heating conditions (Temperature Condition 1 and Temperature Condition 2) in the molding process were changed as shown in Table 2, and the secondary raw material composition and the polyurethane-based composite material were evaluated. The results are shown in Table 3.

[0102] Comparative Examples 3 to 4 A polyurethane-based composite material was produced in the same manner as in Example 1, except that the respective raw materials and their amounts used were changed as shown in Table 1, and the heating conditions (Temperature Condition 1 and Temperature Condition 2) in the molding process were changed as shown in Table 2, and the secondary raw material composition and the polyurethane-based composite material were evaluated. The results are shown in Table 3.

[0103] Comparative Example 5 XDI, which is a diisocyanate (A2), was changed to TDI, and each raw material and its usage amount were changed as shown in Table 1. A polyurethane-based composite material was produced in the same manner as in Example 1 except that the heating conditions (temperature conditions 1 and 2) in the molding process were changed as shown in Table 2, and the secondary raw material composition and the polyurethane-based composite material were evaluated. The results are shown in Table 3.

[0104] Comparative Example 6 A part of XDI, which is a diisocyanate (A2), was changed to HDI, and each raw material and its usage amount were changed as shown in Table 1. A polyurethane-based composite material was produced in the same manner as in Example 1 except that the heating conditions (temperature conditions 1 and 2) in the molding process were changed as shown in Table 2, and the secondary raw material composition and the polyurethane-based composite material were evaluated. The results are shown in Table 3. Regarding the glass transition point of the radically polymerizable polyurethane component (A), since it was in a rubbery state with fluidity at 20 °C, in Table 1, it is indicated as <20 (°C) for a glass transition below 20 °C. Also, in Table 2, T1-TG exceeding 80 °C is indicated as 80< (°C).

[0105] [Table 1]

[0106] [Table 2]

[0107] [Table 3]

Claims

1. A method for manufacturing a molded article made of a polyurethane-based composite material in which a filler is dispersed in a matrix made of a polyurethane-based resin having a crosslinked structure, comprising: An oligomer having a polyurethane skeleton to which a radically polymerizable group is bonded, with a number average molecular weight of 1,500 to 5,000, and a glass transition temperature: T Ｇ The radically polymerizable polyurethane component (A) comprising an oligomer having a glass transition temperature of 35 to 65 °C: 100 parts by mass, a non-additive monomer (B) composed of a radically polymerizable monomer having a radically polymerizable group in the molecule: 5 to 60 parts by mass, 10-hour half-life temperature: T １０ is the above T Ｇ A thermal radical polymerization initiator (C) that is 50°C or higher and 125°C or lower than the above T: 0.01 to 2.0 parts by mass, and an inorganic filler (D): 180 to 550 parts by mass, a raw material composition preparation step of preparing a slurry-like or paste-like raw material composition containing the same, a molding step of filling the raw material composition into a resin molding die and then heating and polymerizing and curing it, The heating in the shaping process is carried out at a temperature 40 °C or higher than the T Ｇ and 10 °C lower than the T １０ for 10 to 168 hours in a temperature range, and then, after the first heating process, a second heating process is carried out at a temperature 25 °C higher than the T １０ to the T １０ for 5 to 72 hours. A method for manufacturing a polyurethane-based composite material molded article, characterized in that.

2. The raw material composition is heated to a temperature 25 °C higher than T of the radically polymerizable polyurethane component Ｇ or higher and to a temperature 10 °C lower than the T １０ to perform a defoaming treatment, and then, while maintaining the temperature, the resin mold is filled. The method for producing a polyurethane-based composite material molded body according to claim 1.

3. The raw material composition preparation step includes a first raw material composition preparation step of preparing a first raw material composition containing a radically polymerizable diol (A1), a non-additive monomer (B), and an inorganic filler (D), and the first raw material composition obtained by this step and a diisocyanate (A2) are mixed and subjected to an addition polymerization reaction to form the radically polymerizable polyurethane component (A). The raw material composition is prepared by blending a thermal radical polymerization initiator (C) into the first raw material composition, at the start or during the addition polymerization step, or after the completion of the addition polymerization step. The method for manufacturing a polyurethane-based composite material molded article according to Claim 1 or 2.

4. As the radically polymerizable diol (A1), the following general formula (1) 【Chemical 1】 〔In the above general formula (1), P is the following structural formula (2) [Chemical Formula 2] {R in the general formula (2) above １ is a hydrogen atom or a methyl group, and X ２ is 0 or 1.} is any divalent group represented by, X １ is each independently 0 or 1, Y is 1 or 2, and when both X １ are 0, Y is 2.] The compound represented by is used, As the diisocyanate (A2), the following general formula (3) 【Chemical Formula 3】 〔In the above general formula (3), A is the following structural formula (4) 【Chemical Formula 4】 {R in the above general formula (4) ３ is each independently a hydrogen atom or a methyl group.} is any divalent group represented by `).` The compound represented by is used, As the non-additive monomer (B), the following general formula (5) [Chemical Formula 5] {R in the general formula (5) above ４ is independently a hydrogen atom or a methyl group, and Z １ is an integer of 1 to 10.} The compound represented by is used, The method for manufacturing a polyurethane-based composite material molded article according to Claim 3.

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