JPS6254807B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for making carbonate polymers. In detail, the particle size is pearl-like spherical with a particle size of 1 to 200μ.
This is a method for producing a carbonate polymer in which an inorganic filler is uniformly dispersed within the particles. The present invention is based on the general formula (However, R is H or CH ₃ , R' is a divalent residue of a saturated aliphatic hydrocarbon, and n is a positive number of 1 to 3), or an unsaturated carbonate of the general formula A monomer mixture of the unsaturated carbonate represented by [A] and at least one copolymerizable monomer selected from methacrylates, diallyl compounds, and vinyl compounds (hereinafter also referred to as other copolymerizable monomer) This is a method for producing a carbonate polymer, which comprises carrying out suspension polymerization in a polymerization tank equipped with a stirrer in the coexistence of a surface-treated inorganic filler. That is, the general formula (However, R is H or CH ₃ , R' is a saturated aliphatic hydrocarbon residue, and n is a positive number of 1 to 3), or an unsaturated carbonate of the general formula [A]
The present invention relates to a method for producing a carbonate polymer, in which a monomer mixture of an unsaturated carbonate represented by the above formula and another copolymerizable monomer is suspension-polymerized in the presence of a surface-treated inorganic filler and in the presence of a suspending agent. Conventionally, in the manufacturing method of polymers of bifunctional monomers, since the polymer has the crosslinked structure and is an insoluble/infusible resin (also called a thermosetting resin), it is impossible to mold it after polymerization. Possible, such as cast polymerization,
It is a common practice to carry out polymerization and molding simultaneously. Therefore, in general, when a polymer of a bifunctional monomer is used in the form of particles or powder, the polymer obtained by the above-mentioned cast polymerization is pulverized. However, the field of use of mechanically crushed granules or powders is often limited because the crushed surface does not become spherical. For example, in the field of tooth material resins for dental crowns or restorations, if the pulverized product is mixed with a liquid monomer and used, the operability is poor, so even if it is an excellent polymer, it is not used. In the case of such thermosetting resins, it is impossible to uniformly disperse and integrate the inorganic filler into the resin after polymerization, so it is necessary to mix the inorganic filler into the monomer and then polymerize it. No. In this case, if the difference in specific gravity between the monomer and the inorganic filler is small and the two have mutual affinity, the inorganic filler can be uniformly dispersed in the monomer, and by casting the monomer and polymerizing it. It is possible to create a thermosetting resin composition in which an inorganic filler is uniformly dispersed and integrated, but inorganic fillers are usually not compatible with hydrocarbons and often have different specific gravity.
It has been difficult to obtain thermosetting resins in which inorganic fillers, particularly fine powder fillers, are uniformly dispersed and integrated. Especially diameter 1~
It seems that there is no technology for uniformly dispersing inorganic fillers in thermosetting resin particles in the shape of microscopic particles of about 200 μm. The present inventors have conducted intensive research to obtain a polymer in which an inorganic filler is uniformly dispersed and integrated in a method for obtaining a spherical polymer by polymerizing a bifunctional monomer. As a result, they discovered that an excellent pearl-like polymer can be obtained by suspension polymerizing a specific unsaturated carbonate in the presence of an inorganic filler, leading to the completion of the present invention. That is, the present invention is based on the general formula (However, R is H or CH ₃ , R' is a saturated aliphatic hydrocarbon residue, and n is a positive number of 1 to 3) or an unsaturated carbonate of the general formula [A]
A method for producing a carbonate polymer, in which a monomer mixture of an unsaturated carbonate represented by the formula and another copolymerizable monomer is polymerized by suspension in the presence of a surface-treated inorganic filler and a suspending agent. .
The carbonate polymer referred to in the present invention refers to a homopolymer obtained by polymerizing an unsaturated carbonate represented by the above general formula, and a polymer obtained by copolymerizing the unsaturated carbonate with another monomer copolymerizable with the unsaturated carbonate. A general term that includes copolymers containing 50% (by weight) or more of the resin portion of unsaturated carbonate. Since the carbonate polymer obtained by the present invention is pearl-like particles, it has good fluidity and operability, and exhibits good properties as an organic filler. For example, it can be easily blended with other polymers and can be used effectively to improve the properties of polymers.
It shows particularly good properties when used as a filling material for dental resins. The unsaturated carbonate used in the present invention has the general formula This is shown in . R in the general formula [A] is limited by the raw material for industrially producing the unsaturated carbonate, and is generally H or CH ₃ . Further, in the general formula [A], R' is preferably a saturated aliphatic hydrocarbon residue, generally an alkylene group having 1 to 6 carbon atoms, due to practical constraints in industrial production.
Further, n in the general formula [A] is generally a positive number of 1 to 3 for practical use. Examples of typical unsaturated carbonates represented by the general formula [A] include diethylene glycol bisallyl carbonate (hereinafter simply referred to as BAC).
), ethylene glycol bisallyl carbonate, triethylene glycol bisallyl carbonate, 1,3-propanediol bisallyl carbonate, 1,4-butanediol bisallyl carbonate, propylene glycol bisallyl carbonate, ethylene glycol bisallyl carbonate Methallyl carbonate and the like are preferably used. The present invention is characterized in that the inorganic filler is uniformly dispersed and integrated into the carbonate polymer.
However, it is generally difficult to uniformly blend an inorganic filler into the carbonate polymer and mold it. In addition, it is generally technically difficult to produce a polymer uniformly containing an inorganic filler. However, in the present invention, the general formula [A]
If an inorganic filler is present in the polymerization system during suspension polymerization of the unsaturated carbonate represented by the formula in an aqueous medium, a carbonate polymer in which the inorganic filler is uniformly dispersed can be obtained. Although it is not clear how the inorganic filler behaves when incorporated into the carbonate polymer in an aqueous medium, the above phenomenon can be said to be surprising. Moreover, although the inorganic filler added to the polymerization system differs slightly depending on the type, it is not only almost completely contained in the carbonate polymer and recovered, but also the desired pearl-like filler, regardless of the amount added. Carbonate polymers can be obtained. In the present invention, when the unsaturated carbonate represented by the general formula [A] is polymerized, favorable results can often be obtained by the presence of a monomer copolymerizable with the unsaturated carbonate. The copolymerizable monomer is not particularly limited as long as it can be copolymerized with the unsaturated carbonate, but examples of commonly used monomers include methyl methacrylate, diethylene glycol dimethacrylate, and bismethacryloxyethoxy. These include methacrylates such as phenylpropane; diallyl compounds such as diallyl phthalate, diallyl terephthalate, and diallyl maleate; and vinyl compounds such as maleic anhydride, vinyl acetate, and styrene. Although the use of these copolymerizable monomers is often effective in improving the properties of the resulting copolymers, the higher the amount of copolymerizable monomers used, the better the unsaturated carbonate polymers are. Generally, it is preferable to select the unsaturated carbonate component in the copolymer so that the content of the unsaturated carbonate component is 50% (by weight) or more. Next, the inorganic filler used in the present invention is not particularly limited, and any known inorganic filler can be used. For example, various inorganic fillers can be used, such as those described in "Powder (Theory and Application)" (edited by Kiichiro Kubo, published by Maruzen Co., Ltd., May 12, 1970), but typical Examples include silica, alumina, glass beads, and crystalline quartz. Depending on the use of the carbonate polymer obtained in the present invention, surface-treated inorganic fillers such as dimethyldichlorosilane, γ-
It is preferable to use a silane coupling agent such as methacryloxypropyltrimethoxysilane or a surface treated with stearic acid. Further, the inorganic filler varies depending on its shape and type, but can be used in any proportion as described above.
Generally, it is most preferred to use inorganic fillers in proportions of 1 to 99%. The shape, particle size, etc. of the inorganic filler may be selected as required, but it is generally most suitable to use one in the range of 0.001 to 10 μm. The suspension polymerization means used in the present invention is not particularly limited. Polymerize in an aqueous medium in the presence of a suspending agent. The suspending agent used in the present invention is not particularly limited, and any suspension agent used in known suspension polymerization can be used. For example, "Polyvinyl chloride - its chemistry and industry" (edited by Kinki Chemical Industry Association, Vinyl Section, Asakura Shobo Publishing, Showa)
(issued June 25, 1936) can be used. Representative examples of commonly used materials include gelatin, starch, sodium alginate, polyvinyl alcohol, polyvinylpyrrolidone, methyl cellulose, hydroxyethyl cellulose, polyvinyl methyl ether, vinyl acetate/
Maleic anhydride copolymer, etc. The amount of the suspending agent to be used varies depending on the type of unsaturated carbonate, polymerization conditions, etc., and cannot be absolutely limited, but in general, it depends on the type of unsaturated carbonate or, in the case of copolymerization, the amount of the unsaturated carbonate and the copolymerizable monomer. It may be added in an amount of 0.1 to 40% (by weight) based on the total amount. Further, in the suspension polymerization, it is necessary to use a polymerization initiator as in generally known suspension polymerization.
Generally known polymerization initiators can be used as the polymerization initiator, and representative examples include azo compounds such as azobisisobutyronitrile, ketone peroxide, diacyl peroxide, dialkyl peroxide, and hydroperoxide. , perester, and other organic peroxides are preferably used. The amount of the polymerization initiator to be used varies depending on the type of unsaturated carbonate, polymerization conditions, etc., and cannot be absolutely limited, but it generally depends on the unsaturated carbonate used or, in the case of copolymerization, the monomer copolymerizable with the unsaturated carbonate. It is suitable to use it in a range of 0.1 to 10% (by weight) based on the total amount. Furthermore, in order to aid in the dispersion of the polymerization reaction system during the polymerization, means such as adding a surfactant such as sodium dodecylbenzenesulfonate or an inorganic salt can be adopted as necessary. The conditions for suspension polymerization in the present invention are not particularly limited and may be appropriately determined as necessary. In general, 20° C. to 120° C. for 30 minutes to 10 hours is suitable, although it varies depending on, for example, the polymerization temperature and the type and amount of the polymerization initiator. The polymerization is carried out using a polymerization tank in the same manner as in known suspension polymerization, and if necessary, under an inert or large atmosphere such as nitrogen, with stirring. The polymerization tank is not particularly limited, but may be a device equipped with a stirrer used for normal suspension polymerization. Generally, stirring blades are of the turbine type, fan turbine type, propeller type, etc., and it is also a preferred embodiment to install a baffle plate in the polymerization tank to aid stirring. The baffle plate may be appropriately provided at a position where it disturbs the flow caused by stirring. For example, a baffle plate of an appropriate height may be erected on the inner wall of the polymerization tank toward the center. The carbonate polymer of the present invention has an average particle size of 1 to
Obtained as a 200μ pearl-shaped spherical polymer.
The particle size and particle size distribution of the carbonate polymer can be changed depending on suspension polymerization conditions such as polymerization type, stirring speed, type and amount of suspending agent, monomer concentration, and sequential addition method of monomers. An electron micrograph is shown in FIG. 1 to show an example of the carbonate polymer obtained by the present invention.
That is, FIG. 1 is an electron micrograph of the carbonate polymer obtained in Example 1. FIG. 2 is a photograph analyzed by an X-ray microanalyzer (abbreviated as XMA) to show that the inorganic filler is uniformly dispersed in the particles shown in FIG. It can be seen from the dispersion of many small dots in the photograph that the inorganic filler is uniformly dispersed in the resin. Unlike conventional pulverized granules and powders, the carbonate polymer of the present invention has an average particle size of, for example, 1 to 1.
Obtained as a 200μ pearl-shaped spherical polymer.
Therefore, there are various advantages. Generally, the carbonate polymer is used for various purposes, and for example, when used for the above-mentioned tooth materials for crowns or restorations, or as an additive to various polymers, an inorganic filler is added. EXAMPLES In order to explain the present invention more specifically, Examples and Comparative Examples will be described below, but the present invention is not limited to these Examples. Example 1 Four baffle plates were installed vertically in the polymerization tank,
After purging the inside of the circular glass reactor, which was stirred at 2300 rpm using a flat-blade turbine as the stirring blade, with nitrogen, 420 ml of ion-exchanged water (hereinafter referred to as water) and 5 g of polyvinyl alcohol (saponification degree 80% 2500) were added.
(120ml of 4% aqueous solution) and 0.5g of methylcellulose
(120ml of 04% aqueous solution) was added. Then BAC200
g, silica (manufactured by Nippon Erosil Co., Ltd., AER-R-
972, lipophilic silica surface-treated with dimethyldichlorosilane, average particle size 10 mμ), and 4.8 g of BPO were added and polymerized at 85° C. for 3 hours under stirring at 3000 rpm. After the polymerization was completed, the contents were filtered and washed successively with water and methanol in order to remove the suspending agent and unreacted monomers. After drying under reduced pressure, 178 g of pearl-like carbonate polymer with an average particle size of 100 μm was obtained. (The obtained polymer is shown in Figure 1) The obtained pearl-like polymer was immersed in a 10% hydrofluoric acid aqueous solution to dissolve the silica that was not incorporated into the polymer, and then XMA analysis was performed ( (See Figure 2). It was confirmed that silica was uniformly dispersed within the polymer. Example 2 The same procedure as in Example 1 was carried out except that silica surface-treated with γ-methacryloxypropyltrimethoxysilane was used. A yield of 160 g of pearl-like carbonate polymer was obtained. Example 3 The same procedure as in Example 1 was carried out except that alumina powder surface-treated with dimethyldichlorosilane was used. A pearl-like carbonate polymer containing alumina was obtained in a yield of 172 g. Example 4 The same procedure as in Example 1 was carried out except that 80 g of quartz powder surface-treated with dimethyldichlorosilane was used. 195 g of carbonate polymer was obtained. Examples 5 to 11 Polymerization was carried out in the same manner as in Example 1, except that 200 g of the mixture of unsaturated carbonate and comonomer shown in Table 1 was used instead of 200 g of BAC used as the unsaturated carbonate, and a carbonate polymer was obtained. I got it. All of the obtained carbonate polymers were pearl-like, and the average particle size and yield were
It was as shown in the table. 【table】

[Brief explanation of the drawing]

Figure 1 is an electron micrograph of the pearl-like polymer obtained by the present invention, and Figure 2 is an electron micrograph of the same type of particles used to take the electron micrograph shown in Figure 1. This is an electron micrograph taken using an X-ray microanalyzer.

Claims (1)

[Claims] 1 General formula [A] (However, R is H or CH ₃ , R' is a divalent residue of a saturated aliphatic hydrocarbon, and n is a positive number from 1 to 3.)
or stirring a monomer mixture of an unsaturated carbonate represented by the general formula [A] and at least one copolymerizable monomer selected from methacrylates, diallyl compounds, and vinyl compounds. A method for producing a carbonate polymer, which comprises carrying out suspension polymerization in an equipped polymerization tank in the coexistence of a surface-treated inorganic filler. 2. The manufacturing method according to claim 1, wherein the polymerization tank is provided with a baffle plate.