JP4761840B2 - Heat extinguishing resin particles - Google Patents

Description

The present invention is a heat extinguishing resin particle that can be decomposed at a low temperature in a short time and does not cause deformation or cracking in the obtained sintered body when used as a binder for ceramics or a lightening material. About.

Organic polymers, in particular thermoplastic polymers represented by polyacrylates, polystyrene, polyethylene, etc., are decomposed by heating, so they have thermal decomposability, have a relatively high softening point temperature, and are excellent. Has moldability. Therefore, organic polymers are widely used as ceramic molding binders, thermal recording resins, heat-disintegrating adhesives and the like by utilizing such thermal decomposability and moldability. In recent years, light ceramics, glass filters, and the like have been manufactured by using organic polymers as micron-sized resin particles, mixed with ceramics, and fired.

As described above, when the organic polymer resin particles are used as a binder for ceramics or a lightening material, the resin components are removed by pyrolyzing or burning the resin particles by firing in a non-oxygen or oxygen atmosphere. There is a need.
However, when the temperature at which the resin component is completely removed in the firing step is close to the fusion temperature of the ceramic raw material powder, glass powder, etc., the residue such as carbon derived from the resin particles is a sintered body. May remain inside. Further, when the temperature at which the resin component is completely removed is higher than the fusing temperature, the sintered body may be deformed. Furthermore, deformation and cracking may occur in the obtained sintered body due to combustion heat generated when the resin component burns. Therefore, in the firing process, resin components can be removed at a lower temperature, the generation of distortion due to combustion heat is small, and resin particles having no residue such as carbon derived from the resin component in the sintered body after firing are desired. It was.

In order to solve such a problem, for example, Patent Document 1 discloses a heat containing a styrene monomer and an α-methylstyrene monomer at a predetermined ratio as a resin material that is easily decomposed even at a low temperature and has good moldability. Degradable styrenic copolymers are disclosed.

However, even such a thermally decomposable styrene copolymer cannot be said to have sufficient thermal decomposability at a low temperature, and when trying to produce a lighter pottery using a large amount of resin, the baking process is performed at 300 ° C. Since it is necessary to carry out at the above high temperature for a long time, there is a problem that the whole manufacturing process takes a long time and the manufacturing efficiency is lowered. Furthermore, the ceramic sintered body obtained by the increase in the heat of combustion of the resin is greatly distorted, resulting in deformation and cracking. Accordingly, there has been a strong demand for resin particles that can be thermally decomposed at a lower temperature and in a shorter time in the firing step.
JP-A-6-41241

In view of the above situation, the present invention can be decomposed at a low temperature and in a short time, and when used as a ceramic binder or a weight-reducing material, the obtained sintered body is not deformed or cracked. An object is to provide heat extinguishing resin particles.

The present invention is a heat extinguishing resin particle containing a polyoxyalkylene resin and a decomposition accelerator, and when heated to a predetermined temperature of 100 to 250 ° C., 10% by weight or more disappears within 1 hour, And it is the heat extinction resin particle whose 50 weight% reduction | decrease temperature is 210 degrees C or less.
Hereinafter, the present invention will be described in detail.

As a result of intensive studies, the present inventors have promoted the thermal decomposition of the polyoxyalkylene resin by containing the polyoxyalkylene resin and the decomposition accelerator as a result of the heat-extinguishing resin particles, and a predetermined temperature of 100 to 250 ° C. Heat extinguishing resin particles exhibiting excellent decomposability in a low temperature region such that a certain amount disappears within 1 hour by heating to a temperature and the 50% by weight reduction temperature is 210 ° C. or less can be obtained. I found. In addition, when the heat extinguishing resin particles having excellent low-temperature decomposability are used as a binder for ceramics or a lightening material, it can be molded with good handling properties at room temperature, and in the firing process, combustion heat The present inventors have found that manufacturing efficiency can be improved by reducing the time required for the firing process and the like while suppressing deformation and cracking of the ceramic molded product due to the above.

The heat-extinguishing resin particles of the present invention contain a polyoxyalkylene resin.
The polyoxyalkylene resin is decomposed into low molecular weight hydrocarbons, ethers, etc. by heating to a predetermined temperature of 100 to 250 ° C., and then disappears due to a phase change such as a combustion reaction or evaporation. Demonstrate.

The polyoxyalkylene resin is not particularly limited, but is preferably at least one selected from the group consisting of polyoxypropylene, polyoxyethylene, and polyoxytetramethylene. When a polyoxyalkylene resin other than the above is used, predetermined heat extinction properties and particle strength may not be obtained. Of these, polyoxypropylene is more preferable. In order to obtain an appropriate heat extinction property and particle strength, it is preferable that 50% by weight or more of the polyoxyalkylene resin contained in the heat extinction resin particles is polyoxypropylene.

Examples of commercially available polyoxyalkylene resins include MS polymers S-203, S-303, and S-903 (manufactured by Kaneka Corporation); Silyl SAT-200, MA-403, and MA-447. (Above, manufactured by Kaneka); Epion EP103S, EP303S, EP505S (above, manufactured by Kaneka); PEG200, PEG300, PEG400, PEG600, PEG1000 (above, manufactured by NOF Corporation); UNIOR D-250, D-400, D -700, D-1000 (above, manufactured by NOF Corporation); Exester ESS-2410, ESS-2420, ESS-3630 (above, manufactured by Asahi Glass Co., Ltd.) and the like.

Although it does not specifically limit as molecular weight of the said polyoxyalkylene resin, The minimum with a preferable number average molecular weight is 300, and a preferable upper limit is 1 million. If it is less than 300, high heat extinction may not be realized, and if it exceeds 1,000,000, high particle strength may not be realized.

In the heat-extinguishing resin particles of the present invention, a preferred lower limit for the content of the polyoxyalkylene resin is 5% by weight. If it is less than 5% by weight, the heat extinguishing resin particles obtained may have insufficient heat extinguishing properties.

The heat extinguishing resin particle of the present invention contains a decomposition accelerator.
In this specification, the decomposition accelerator means a substance that generates radicals at a predetermined temperature and accelerates a polymer decomposition reaction caused by radicals including depolymerization.
By containing the decomposition accelerator, the decomposition of the polyoxyalkylene resin is promoted, and the heat extinguishing resin particles can be extinguished in a short time at a lower temperature.
The decomposition accelerator is not particularly limited, and examples thereof include azo compounds and organic peroxides.

As the decomposition accelerator, it is preferable to use a decomposition accelerator having a one-hour half-life temperature of 100 to 170 ° C and / or a decomposition accelerator having a temperature of 170 to 250 ° C. In the present invention, either one of a decomposition accelerator having a one-hour half-life temperature of 100 to 170 ° C. and a decomposition accelerator having a half-life temperature of 170 to 250 ° C. may be used depending on the purpose. Good.

When using a decomposition accelerator having a one-hour half-life temperature of 100 to 170 ° C., the heat extinguishing resin particles can be rapidly decomposed in a low temperature region at the initial stage of the ceramic firing process, so that the firing process is shortened and manufactured. It can be suitably used for the purpose of improving the efficiency. In addition, when using a decomposition accelerator having a one-hour half-life temperature of 170 to 250 ° C., since decomposition of heating is promoted in a high temperature region, the purpose is to promote decomposition in the later stage of the firing step. It can be used suitably. Further, when a decomposition accelerator having a one-hour half-life temperature of 100 to 170 ° C. and a decomposition accelerator having a one-hour half-life temperature of 170 to 250 ° C. are used in combination, a rapid decomposition heat generation at the initial stage of the firing process is suppressed. Therefore, it is suitable for the purpose of shortening the firing process while uniformly promoting the decomposition over the latter stage of the firing process.
In this specification, the 1-hour half-life temperature is a solution having an initial concentration of the decomposition accelerator of 0.05 to 0.1 mol / l using a solvent inert to the decomposition accelerator such as benzene. Is prepared, and after pyrolysis in a glass container purged with nitrogen for 1 hour, the concentration of the decomposition accelerator is half the initial concentration.

The decomposition accelerator is preferably an azo compound or an organic peroxide.
Examples of the azo compound include 1,1-azobis (cyclohexane-1-carbonitrile) (106 ° C.), 1-[(1-cyano-1-methylethyl) azo] formamide (123 ° C.), 2, 2 -Azobis [N- (2-propenyl) -2-methylpropionamide] (117 ° C), 2,2-azobis (N-butyl-2-methylpropionamide) (132 ° C), 2,2-azobis (N -Cyclohexyl-2-methylpropionamide) (134 ° C.) and the like. In addition, the temperature in the said parenthesis shows 1 hour half-life temperature.

Among the azo compounds, 1,1-azobis (cyclohexane-1-carbonitrile) (manufactured by Wako Pure Chemical Industries, Ltd .; V-40) and 2,2-azobis (N-cyclohexyl) exhibit particularly excellent decomposability. -2-methylpropionamide) (manufactured by Wako Pure Chemicals; Vam-111) can be preferably used.

Among the above organic peroxides, examples of the organic peroxide having a one-hour half-life temperature of 100 to 170 ° C. include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane. (106 ° C.) 1,1-bis (t-butylperoxy) cyclohexane (111 ° C.), t-butylperoxy-3,5,5-trimethylhexanoate (119 ° C.), t-butyl peroxyacetate (121 ° C. ), N-butyl-4,4-bis (t-butylperoxy) valerate (126 ° C.), t-butylcumyl peroxide (137 ° C.), 2,5-dimethyl-2,5-di (t-butylperoxy) ) Hexin-3 (150 ° C.), p-menthane hydroperoxide (151 ° C.) and the like; Examples of the organic peroxide having a one-hour half-life temperature of 170 to 250 ° C. include di- Isopropyl benzene hydroperoxide (173 ℃), 1,1,3,3- tetramethylbutyl hydroperoxide (182 ° C.), cumene hydroperoxide (188 ° C.), such as t- butyl hydroperoxide (196 ° C.) and the like. In addition, the temperature in the said parenthesis shows 1 hour half-life temperature.

Among the above organic peroxides, t-butylperoxy-3,5,5-trimethylhexanoate (manufactured by NOF Corporation; Perbutyl 355), n-butyl-4,4 are shown as those exhibiting particularly excellent degradability. -Bis (t-butylperoxy) valerate (manufactured by NOF Corporation; Perhexa V), t-butylcumyl peroxide (manufactured by NOF Corporation; perbutyl C), 2,5-dimethyl-2,5-di (t-butyl Peroxy) hexyne-3 (Nippon Yushi Co., Ltd .; Perhexine 25B), p-menthane hydroperoxide (Nippon Yushi Co., Ltd .; Permenta H), diisopropylbenzene hydroperoxide (Nippon Yushi Co., Ltd .; Park Mill P), 1,1 , 3,3-tetramethylbutyl hydroperoxide (manufactured by NOF Corporation; Perocta H) can be suitably used.

In the heat-extinguishing resin particles of the present invention, the preferable lower limit of the content of the decomposition accelerator is 0.1% by weight, and the preferable upper limit is 10% by weight. If it is out of the above range, the effect of promoting the decomposition of the heat extinguishing resin particles may not be sufficiently exhibited.

When the heat extinguishing resin particles of the present invention are heated to a predetermined temperature of 100 to 250 ° C., 10% by weight or more disappears within 1 hour.
The heat extinguishing resin particles of the present invention contain the above-described decomposition accelerator, thereby promoting the decomposition of the heat extinguishing resin particles, and exhibit extremely excellent decomposability even in a low temperature range of 100 to 250 ° C. More than 10% by weight disappears. If the time required for extinction exceeds 1 hour, the production efficiency decreases, and if the extinguished portion is less than 10% by weight, the amount of heat generation is reduced and the effect of suppressing deformation becomes insufficient. Moreover, it is preferable that 10 weight% or more will lose | disappear within 1 hour by heating the heat extinction resin particle of this invention to the predetermined temperature of 120-200 degreeC.

The heat extinguishing resin particles of the present invention have a 50% weight loss temperature of 210 ° C. or lower.
The heat extinguishing resin particles of the present invention contain the above-described decomposition accelerator, thereby promoting the decomposition of the heat extinguishing resin particles, exhibiting extremely excellent decomposability, and having a 50% weight loss temperature of 210 ° C. or less. If the 50% weight reduction temperature exceeds 210 ° C., a long time is required for the production process, so that the production efficiency is lowered, or a residue such as carbon derived from the resin component is generated in the sintered body after firing. The heat extinguishing resin particles of the present invention preferably have a 50% weight loss temperature of 180 ° C. or lower.

The preferable lower limit of the decomposition start temperature of the heat extinguishing resin particles of the present invention is 110 ° C., and the preferable upper limit is 200 ° C. If it is less than 110 ° C., decomposition may be started before performing the firing step, and the performance of the obtained product may be deteriorated. If it exceeds 200 ° C., 10% by weight of the heat extinguishing resin particles within one hour. The above may not disappear.
In this specification, the decomposition start temperature refers to a temperature at which the weight loss rate becomes 5% or more by heating. For example, DSC-6200 (manufactured by Seiko Instruments Inc.) or the like is used for thermogravimetric analysis ( TGA) can be obtained.

The preferable lower limit of the average particle diameter of the heat extinguishing resin particles of the present invention is 1 μm, and the preferable upper limit is 500 μm. If it is outside the above range, it may be difficult to produce the heat extinguishing resin particles of the present invention with a good yield in a production method such as suspension polymerization. It is possible to efficiently produce extinct resin particles. A more preferable lower limit is 5 μm, and a more preferable upper limit is 200 μm.

The method for producing the heat extinguishing resin particles of the present invention is not particularly limited. For example, a polyoxyalkylene macromonomer, a mixed monomer of a polyoxyalkylene macromonomer and another polymerizable monomer, and a decomposition accelerator. Examples of the polymerization method include a polymerization method using a known polymerization method such as a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, a soap-free polymerization method, a miniemulsion polymerization method, and the like. Of these, the suspension polymerization method is preferred.
In the present specification, the macromonomer refers to a high molecular weight linear molecule having a polymerizable functional group such as a vinyl group at the molecular end, and the polyoxyalkylene macromonomer is a polymer having a linear portion having a poly moiety. A macromonomer composed of oxyalkylene.

The functional group contained in the polyoxyalkylene macromonomer is not particularly limited. For example, polymerizable unsaturated hydrocarbon such as (meth) acrylate, isocyanate group, epoxy group, hydrolyzable silyl group, hydroxyl group, carboxyl group Etc. Among them, a polyoxyalkylene macromonomer containing a polymerizable unsaturated hydrocarbon capable of radical polymerization is preferable because it can more easily produce a heat-extinguishing resin particle, and a polyoxyalkylene containing a (meth) acryloyl group having high polymerization reactivity. An alkylene macromonomer is more preferred.
Further, the number of functional groups contained in the polyoxyalkylene macromonomer is not particularly limited, but if a macromonomer having two or more functional groups is used, heat extinguishing resin particles having high compressive strength can be obtained by crosslinking. Can do.

Although it does not specifically limit as molecular weight of the polyoxyalkylene unit contained in the said polyoxyalkylene macromonomer, The minimum with a preferable number average molecular weight is 300, and a preferable upper limit is 1 million. If it is less than 300, sufficient heat extinction may not be obtained, and if it exceeds 1,000,000, sufficient particle strength may not be obtained.

Specific examples of the polyoxyalkylene macromonomer include polyoxyethylene di (meth) acrylate (manufactured by NOF Corporation; Blemmer PDE-400, PDE-600, ADE-400), polyoxypropylene di (meth). Acrylate (manufactured by NOF Corporation: Blemmer PDP-400, PDP-700, ADP-400), polyoxytetramethylene di (meth) acrylate (manufactured by NOF Corporation; Blemmer PDT-650, ADT-250), polyoxyethylene- Polyoxytetramethylene methacrylate (manufactured by NOF Corporation; Bremer 55PET-800) and the like can be mentioned.

Although it does not specifically limit as another polymerizable monomer when making it copolymerize with the said polyoxyalkylene macromonomer, Since it can manufacture simply, a radically polymerizable monomer is suitable. It does not specifically limit as said radically polymerizable monomer, For example, (meth) acrylate, (meth) acrylonitrile, (meth) acrylic acid, styrene and its derivative (s), vinyl acetate, etc. are mentioned.

Furthermore, as another polymerizable monomer used together with the polyoxyalkylene macromonomer, a polyfunctional monomer may be added for the purpose of improving the particle strength. The type of the polyfunctional monomer is not particularly limited, and examples thereof include acrylic polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, divinylbenzene, and the like.

When producing the heat extinguishing resin particles of the present invention, the particles containing a polyoxyalkylene resin and a decomposition accelerator may be coated with an organic resin and encapsulated. The encapsulation method is not particularly limited, and examples thereof include a coacervation method, a submerged drying method, an interfacial polymerization method, and an in-situ polymerization method.

According to the present invention, it can be decomposed at a low temperature in a short time, and when used as a binder for ceramics or a lightening material, the resulting sintered body does not undergo deformation or cracking and is thermally extinguished. Resin particles can be provided.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1
As a monomer component, 80 parts by weight of polyoxypropylene dimethacrylate (number of polyoxypropylene units = about 13; manufactured by Nippon Oil & Fats Co., Ltd., Blenmer PDP-700), 20 parts by weight of methyl methacrylate, and peroxyketal (Nippon Oils and Fats as a decomposition accelerator) A monomer solution was prepared by mixing and stirring 1 part by weight of Perhexa V) and 0.3 part by weight of azobisisobutyronitrile (AIBN) as a polymerization initiator.
The total amount of the monomer solution thus obtained is added to 300 parts by weight of an aqueous solution of 1% by weight of polyvinyl alcohol (PVA) and 0.02% by weight of sodium nitrite, and stirred using a stirring and dispersing device to obtain an emulsified suspension. It was.

Next, using a 20 liter polymerization vessel equipped with a stirrer, jacket, reflux condenser and thermometer, the inside of the polymerization vessel was depressurized, and after deoxidizing the vessel, the pressure was returned to atmospheric pressure with nitrogen gas. The inside of the polymerization vessel was set to a nitrogen atmosphere. The entire amount of the resulting emulsified suspension was charged all at once into the polymerization vessel, and the polymerization was started by raising the temperature of the polymerization vessel to 60 ° C. After polymerization for 8 hours, the polymerization vessel was cooled to room temperature to obtain a slurry. The obtained slurry was dehydrated with a dehydrator and vacuum dried to obtain heat extinguishing resin particles.
In addition, it was 60 micrometers when the average particle diameter of the obtained heat extinction resin particle was measured.

(Example 2)
As a monomer component, 50 parts by weight of polyoxypropylene dimethacrylate (number of polyoxypropylene units = about 9; manufactured by Nippon Oil & Fats Co., Ltd., Blenmer PDP-400), 50 parts by weight of methyl methacrylate, hydroperoxide (Nippon Oils and Fats as a decomposition accelerator) Except for using 5 parts by weight of Perocta H), heat extinguishing resin particles were obtained in the same manner as in Example 1.
In addition, it was 57 micrometers when the average particle diameter of the obtained heat extinction resin particle was measured.

(Example 3)
As monomer components, 80 parts by weight of polyoxyethylene-polyoxytetramethylene methacrylate (the number of polyoxyethylene units = about 10, the number of polyoxytetramethylene units = about 5; manufactured by NOF Corporation, BLEMMER 55PET-800), methyl methacrylate Example 1 except that 20 parts by weight, 1 part by weight of a dialkyl peroxide (manufactured by NOF Corporation, Perhexin 25B) and 5 parts by weight of hydroperoxide (manufactured by NOF Corporation, Parkmill P) were used as the decomposition accelerator. By this method, heat extinguishing resin particles were obtained.
In addition, it was 45 micrometers when the average particle diameter of the obtained heat extinction resin particle was measured.

(Comparative Example 1)
Heat extinguishing resin particles were obtained in the same manner as in Example 1 except that the decomposition accelerator was not used.
In addition, it was 58 micrometers when the average particle diameter of the obtained heat extinction resin particle was measured.

(Comparative Example 2)
As the monomer component, 10 parts by weight of polyoxypropylene dimethacrylate (number of polyoxypropylene units = about 9; manufactured by Nippon Oil & Fats Co., Ltd., Blenmer PDP-400), 90 parts by weight of methyl methacrylate, and no decomposition accelerator were used. Obtained heat extinguishing resin particles by the same method as in Example 1.
In addition, it was 52 micrometers when the average particle diameter of the obtained heat extinction resin particle was measured.

(Evaluation)
The following evaluation was performed on the heat extinguishing resin particles obtained in Examples 1 to 3 and Comparative Examples 1 and 2.
The results are shown in Table 1.

(1) Measurement of loss on heating By using DSC-6200 (manufactured by Seiko Instruments Inc.), the decomposition start temperature and the 50% by weight decrease temperature were measured by measuring while increasing the temperature at a rate of temperature increase of 5 ° C./min. Further, the weight loss rate at 250 ° C. was measured.

According to the present invention, it can be decomposed at a low temperature in a short time, and when used as a binder for ceramics or a lightening material, the resulting sintered body does not undergo deformation or cracking and is thermally extinguished. Resin particles can be provided.

Claims (4)

By containing a polyoxyalkylene resin and a decomposition accelerator and heating to a predetermined temperature of 100 to 250 ° C., 10% by weight or more disappears within 1 hour, and a 50% by weight reduction temperature is 210 ° C. or less. The decomposition accelerator includes 1,1-bis (t-butylperoxy) cyclohexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyacetate, n-butyl-4,4-bis ( t-butylperoxy) valerate, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide and 1,1 is at least one selected from the group consisting of 3,3-tetramethylbutyl hydroperoxide, and minute Heating extinguishing resin particles characterized by containing the accelerator 1 to 10% by weight. Heating to a predetermined temperature of 120 to 200 ° C, 10% by weight or more disappears within 1 hour, and 50% by weight reduction temperature is 180 ° C or less. Dissipative resin particles. The heat extinguishing resin according to claim 1 or 2, comprising a decomposition accelerator having a one-hour half-life temperature of 100 to 170 ° C and / or a decomposition accelerator having a one-hour half-life temperature of 170 to 250 ° C. particle. 4. The heat extinguishing resin particles according to claim 1, 2 or 3, wherein the average particle diameter is 5 to 200 [mu] m.