JP2997385B2 - Manufacturing method of lightweight polyester resin powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to rubber, plastic,
The present invention relates to a method for producing a lightweight polyester resin powder that can be used as a lightening agent in sealants, adhesives, oil clay, paper clay, FRP, and the like.

[0002]

2. Description of the Related Art Conventionally, in articles related to transportation, carrying, etc., weight reduction for reducing energy consumption has been achieved, and lightening materials added to plastic, rubber, oil clay, paper clay and the like have been used. Are known. This lightening material is a powder having voids therein, and for example, silica balloons such as silica balloons, glass balloons, and shirasu balloons are known.

A hollow or porous thermoplastic resin powder formed from a polymerizable monomer such as vinyl acetate, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, styrene, acrylonitrile, and vinylidene chloride is also known. Have been.

Further, the present inventors have disclosed Japanese Patent Laid-Open No. 5-14838.
No. 4 discloses a lightweight material for a porous crosslinked polyester resin powder produced using an oxide and / or hydroxide of an alkaline earth metal, and a lightweight composition containing the same.

[0005]

However, silica-based balloons have a problem that when they are mixed and kneaded with plastic or rubber or the like, the balloon is broken, and the function as a lightweight material cannot be achieved.

In addition, when thermoplastic resin powders are blended and applied to plastics or rubbers, heating,
The bead was deformed or melted by heat during pressure kneading, injection, extrusion, pressure molding, and the like, so that the function as a lightweight material could not be achieved.

[0007] The lightening material disclosed in Japanese Patent Publication No. 5-148384 is formed from a crosslinked polyester, and therefore is not easily deformed or melted by heating or the like. Is a lightweight material that can be used. However, depending on the manufacturing method,
There is a problem that a material having a sufficiently low specific gravity cannot be obtained.
Also, the pores formed on the particle surface and inside are large, and when mixed with liquid substances such as water, plasticizer, mineral oil, styrene monomer, alcohol, etc., and stored for a long time, these liquid substances are contained in the particle powder. There was also a problem that the material was absorbed in the pores and could not sufficiently achieve its function as a lightweight material.

[0008] The present inventors have disclosed in Japanese Patent Application No.
No. -102129 proposes a method for producing a polyester resin powder having a lower specific gravity. In this production method, a polyester resin powder having a low specific gravity is produced by using an active calcium hydroxide slurry and / or a magnesium hydroxide slurry whose sedimentation volume in water is within a predetermined range. However, large voids may be formed on the surface of the resin powder, and the internal voids may be non-uniform, and a lightweight polyester resin powder having fine and uniform voids is desired.

SUMMARY OF THE INVENTION An object of the present invention is to satisfy such a conventional demand, and fine pores are uniformly formed at a low specific gravity without being easily broken by heating or kneading. An object of the present invention is to provide a method for producing a lightweight polyester resin powder.

[0010]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned conventional problems. As a result, the inventors have used isophthalic unsaturated polyester as unsaturated polyester, and alkali metal water as base. By using oxides, carbonates and / or bicarbonates, and adding the base in an amount of 0.05 to 0.8 equivalents relative to the acid value of the unsaturated polyester, the base is easily destroyed by heating or kneading. The present inventors have found that a lightweight polyester resin powder having a low specific gravity and uniformly formed fine pores can be obtained, and the present invention has been completed.

That is, according to the production method of the present invention, an aqueous solution of a base is dispersed in an oil phase comprising an unsaturated polyester and a polymerizable monomer, and the dispersion is redispersed in an aqueous solution of a suspension stabilizer to form a crosslink. This is a method for producing a porous polyester resin powder by curing and drying the same, using an isophthalic unsaturated polyester as an unsaturated polyester, and a hydroxide or carbonate of an alkali metal as a base.
And / or bicarbonate, wherein the amount of the base added is 0.05 to 0.8 equivalent to the acid value of the unsaturated polyester.

One of the features of the production method of the present invention is that an isophthalic unsaturated polyester is used as the unsaturated polyester. The isophthalic acid-based unsaturated polyester is an unsaturated polyester resin in which isophthalic acid is used as a main component of a saturated acid as a raw material of the unsaturated polyester resin. The unsaturated polyester is obtained by polymerizing a mixture of such a saturated acid and an α, β-unsaturated acid with a polyhydric alcohol such as a dihydric alcohol or a trihydric alcohol.

As the unsaturated acid, for example, fumaric acid, maleic acid, itaconic acid and the like can be mentioned. Further, as other saturated acids, succinic acid, glutaric acid, tetrahydrophthalic acid, adipic acid, sebacic acid and the like, or orthophthalic acid and terephthalic acid may be contained in small amounts.

The dihydric alcohol and trihydric alcohol include, for example, ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, 1,3-propanediol, 1,6-hexanediol, and trimethylolpropane. .

Although the acid value of the unsaturated polyester is not particularly limited, it is preferable to use an unsaturated polyester having an acid value of about 5 to 30 mgKOH / g in consideration of the stability of the water-in-oil emulsion. preferable.

According to the present invention, a polymerizable monomer is mixed with the unsaturated polyester. As the polymerizable monomer,
There is no particular limitation, and examples thereof include styrene, chlorostyrene, vinyltoluene, divinylbenzene, acrylic acid, methyl acrylate, acrylonitrile, ethyl acrylate and diallyl phthalate.

The mixing ratio of the unsaturated polyester and the polymerizable monomer is not particularly limited, but is preferably 20 to 80% by weight of the unsaturated polyester and 80 to 20% by weight of the polymerizable monomer. When the content of the unsaturated polyester is 20% by weight, the heat resistance of the crosslinked and cured resin powder may decrease. On the other hand, if it exceeds 80% by weight, the viscosity of the oil phase becomes high and stirring may be difficult.

According to the present invention, a water-in-oil emulsion is formed by adding and dispersing an aqueous solution of a base into an oil phase comprising the unsaturated polyester and a polymerizable monomer. In the present invention, an alkali metal hydroxide, carbonate, and / or bicarbonate is used as a base to be added to such an oil phase. As the alkali metal, sodium, potassium, and lithium are preferable from the viewpoint of ease of handling and price.

According to the present invention, the amount of the base added is 0.05 to 0.8 with respect to the acid value of the unsaturated polyester.
Equivalent, preferably 0.1 to 0.5 equivalent, more preferably 0.1 to 0.3 equivalent. When the amount of the base to be added is too small, a stable water-in-oil emulsion may be difficult to be formed. Conversely, when the amount of the base is too large, the viscosity of the water-in-oil emulsion becomes high, which makes it difficult to handle. There is.

In the present invention, the amount of water in the aqueous base solution added to the oil phase composed of the unsaturated polyester and the polymerizable monomer is 100% by weight of the oil phase composed of the unsaturated polyester and the polymerizable monomer. Parts, the amount of the aqueous base solution is 10
It is preferable to adjust the amount to be 0 to 800 parts by weight. In the present invention, such a water-in-oil emulsion is added to an aqueous solution containing a suspension stabilizer, dispersed, cross-linked and cured, and dried to obtain a porous lightweight polyester resin powder. During drying, the water in the polyester resin powder evaporates, and the portion where the water was present becomes a void. Therefore, the larger the amount of water in the dispersed particles, the higher the porosity of the polyester resin powder. Therefore, when the amount of water in the aqueous base solution is too small, it may not be possible to obtain a porous polyester resin powder having a small apparent specific gravity and a high porosity.
If the amount of water is too large, it may be difficult to form a stable water-in-oil emulsion.

In order to form a water-in-oil emulsion by adding and dispersing the above aqueous base solution into an oil phase comprising an unsaturated polyester and a polymerizable monomer, a general method such as stirring is employed. be able to. For example, an aqueous base solution may be gradually added to the oil phase and vigorously stirred with a disper mill, colloid mill or the like. The stirring speed is not particularly limited, but the peripheral speed of the stirring blade is usually about 10 to 60 m / sec, preferably about 15 to 30 m / sec.

The water-in-oil emulsion formed as described above is added to an aqueous solution containing a suspension stabilizer and redispersed. Examples of the suspension stabilizer for redispersing the water-in-oil emulsion include polyvinyl alcohol, partially saponified polyvinyl alcohol, hydroxymethyl cellulose, hydroxyethyl cellulose, and the like.

The suspension stabilizers can be used alone or in a mixture of two or more. The concentration of the suspension stabilizer in the aqueous solution may be appropriately selected depending on the particle size of the target polyester resin particles and the like, but is generally preferably about 0.05 to 3% by weight.

The stirring speed when the water-in-oil emulsion is redispersed in the aqueous solution of the suspension stabilizer can be appropriately selected according to the intended particle size of the polyester resin particles. Generally, when the stirring speed is high, particles having a small particle size are obtained, and when the stirring speed is low, particles having a large particle size are obtained.

Next, the redispersed water-in-oil emulsion is cross-linked and hardened. Crosslinking and curing can be performed by a usual method, for example, crosslinking and curing can be performed by adding a polymerization initiator while stirring the redispersion. As the polymerization initiator, those used as the polymerization initiator for the unsaturated polyester resin can be used. In particular,
For example, organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, cumene peroxide, t-butyl peroxide, inorganic peroxides such as ammonium persulfate, sodium persulfate and potassium persulfate, and methyl ethyl ketone peroxide-cobalt organic acid Redox-based polymerization initiators such as salts and cumene hydroperoxide-cobalt organic acid salts can be used.

The polymerization initiator may be added to the oil phase of the unsaturated polyester and the polymerizable monomer. In the redox-based polymerization initiator composed of two components, one component may be added to the oil phase and the other component may be added to the redispersion.

The amount of the polymerization initiator used is not particularly limited, but is usually 0.5 to 100 parts by weight based on 100 parts by weight of the oil phase.
It may be about 5 parts by weight. The polymerization temperature is not particularly limited and is appropriately selected depending on the polymerization initiator used, and is usually about 10 to 40 ° C. Also, the stirring speed is not particularly limited, but usually the peripheral speed of the stirring blade is 1
The speed may be about 10 to 10 m / sec.

Drying after crosslinking and curing can be generally carried out by heating and drying. The heating temperature is not particularly limited, but the heating can be usually performed at about 80 to 120 ° C. In the present invention, the moisture in the polyester bead is evaporated by this drying, and a void is formed. Therefore, when drying, it is preferable to dry while thoroughly mixing each polyester resin powder, and it is preferable to dry using a rotary dryer as a dryer.

Although the particle diameter of the resin powder produced by the production method of the present invention is not particularly limited, resin powders having various particle diameters in a wide range of, for example, 3 μm to 3 mm can be produced. .

[0030]

According to the present invention, an isophthalic unsaturated polyester is used as an unsaturated polyester, and a hydroxide, carbonate and / or bicarbonate of an alkali metal is used as a base, so that heating, kneading, etc. Thus, a polyester resin powder is produced in which fine pores are uniformly formed at a low specific gravity without being easily broken. The reason why the combination of the isophthalic unsaturated polyester and a base such as an alkali metal hydroxide gives a polyester resin powder having a low specific gravity and uniformly formed fine pores is not clear. However, by such a combination, it is possible to obtain a polyester resin powder having a significantly lower specific gravity than the conventional one and having fine pores formed uniformly on the surface and inside of the particles. Therefore, according to the present invention, a lightweight material having a sufficiently low specific gravity as a lightweight material and having a strong structure that is not broken by heating or kneading can be obtained.

[0031]

EXAMPLES Polyester resin powders were produced using the raw materials and amounts shown in Table 1 (Examples) and Table 2 (Comparative Examples). The amounts of the bases shown in Tables 1 and 2 are equivalents to one equivalent of the carboxyl group of the unsaturated polyester resin, and are calculated from the acid value of the liquid unsaturated polyester resin.

The raw materials used are as follows. Ingredients : Isophthalic acid-based unsaturated polyester resin A 3.0 mol of isophthalic acid, 4.0 mol of fumaric acid, 1.75 mol of ethylene glycol, 5.
A liquid unsaturated polyester resin having an acid value of 17 mgKOH / g in which 65 parts by weight of a resin obtained by reacting 6 moles are dissolved in 35 parts by weight of styrene.

Isophthalic acid-based unsaturated polyester resin B An acid value obtained by dissolving 60 parts by weight of a resin obtained by reacting 1.0 mol of isophthalic acid, 1.0 mol of fumaric acid and 2.2 mol of propylene glycol in 35 parts by weight of styrene. 12mgKOH /
g of liquid unsaturated polyester resin.

-Orthophthalic unsaturated polyester resin A: 1.0 mol of phthalic anhydride, 1.0 mol of maleic anhydride,
Resin 65 reacted with 2.2 mol of propylene glycol
An acid value of 20 mgK in which 35 parts by weight of styrene was dissolved.
OH / g liquid unsaturated polyester resin.

Orthophthalic unsaturated polyester resin B 60 parts by weight of a resin obtained by reacting 1.0 mol of tetrahydrophthalic anhydride, 1.0 mol of maleic anhydride, and 2.1 mol of ethylene glycol are dissolved in 40 parts by weight of styrene. Liquid unsaturated polyester resin having an acid value of 33 mgKOH / g.

Styrene monomer: Reagent, manufactured by Wako Pure Chemical Co., Ltd. Cobalt naphthenate: Reagent, cobalt content 6%, manufactured by Wako Pure Chemical Co., Ltd. Sodium hydroxide: Reagent, manufactured by Wako Pure Chemical Co., Ltd. Potassium hydroxide: Reagent・ Wako Pure Chemical Co., Ltd. ・ Lithium hydroxide: Reagent, Wako Pure Chemical Co., Ltd. ・ Sodium carbonate: Reagent, Wako Pure Chemical Co., Ltd. ・ Sodium bicarbonate: Reagent, Wako Pure Chemical Co., Ltd. ・ Calcium hydroxide: Reagent, Wako Pure • Magnesium oxide: Reagent, manufactured by Wako Pure Chemical Industries, Ltd. • Polyvinyl alcohol: Degree of polymerization 2000, degree of saponification 8
0% ・ Hydroxyethyl cellulose: Reagent, manufactured by Wako Pure Chemical Co., Ltd. ・ Methyl ethyl ketone peroxide: Trade name: Kayamec A, manufactured by Kayaku Akzo

Preparation of Polyester Resin Powder Substance A shown in Tables 1 and 2 was mixed with
While stirring at a peripheral speed of 0 m / sec, an aqueous solution (or water suspension) of the substance B was gradually added to prepare a water-in-oil emulsion. Next, the emulsion was added to a previously prepared aqueous solution of the substance C, and stirring was continued at a peripheral speed of 10 m / sec for 10 minutes. Further, the substance D was added, and stirring was further continued for 2 hours. The resin layer was cured, and a slurry of crosslinked polyester resin particles was obtained. The slurry of the crosslinked polyester resin particles was filtered and washed with water, and the obtained cake was dried at 110 ° C. for 8 hours to obtain a polyester resin powder. In both the examples and comparative examples, resin powders having an average particle diameter of 20 to 30 μm were obtained. With respect to the obtained polyester resin powder, the specific gravity, the pore diameter on the particle surface, and the vesicle (cell) diameter inside the particle were measured as follows, and are shown in Tables 1 and 2.

Measurement method of specific gravity After the obtained polyester resin powder is mixed with epoxy resin and cured, the cured epoxy resin is cured according to JIS-K-7.
The specific gravity of the polyester powder mixed into the resin was calculated from the specific gravity of the obtained cured epoxy resin by measuring in accordance with the underwater substitution method in accordance with No. 112.

Method for Measuring Pore Diameter on Particle Surface The pore diameter on the particle surface of the obtained polyester resin powder was measured with a mercury intrusion porosimeter (manufactured by Erlo-Karma).

Method for measuring vesicle diameter inside particles Embedding polyester resin powder in epoxy resin, after curing, cutting the surface of the cured product with a sharp blade, and using a scanning electron microscope to observe vesicles with particle cross sections. The diameter was measured.

Examples 2, 4, and Comparative Example 6
Using a cured product embedded with an epoxy resin, the particle cross section and the particle surface were observed with a scanning electron microscope in the same manner as in the method for measuring the vesicle diameter inside the particles. 1 and 2 show the inside and the particle surface of Example 2, and FIGS.
5 shows the inside and the particle surface of Example 4, and FIGS. 5 and 6 show the inside and the particle surface of Comparative Example 6.

[0042]

[Table 1]

[0043]

[Table 2]

As is apparent from Table 1, in Examples 1 to 9 in which an isophthalic acid-based polyester resin was used according to the present invention and a hydroxide, carbonate or bicarbonate of an alkali metal was used as a base, 0.15 was used. A polyester resin powder having a low specific gravity of about 0.35 is obtained. The pore diameter on the particle surface is 0.23 to 0.35 μm and the vesicle diameter inside the particle is 0.5 to 1.5 μm, and fine pores are uniformly formed.

On the other hand, as is apparent from Table 2,
In those using the orthophthalic acid-based polyester resin (Comparative Examples 1 to 3) and those using calcium hydroxide or magnesium oxide as the base (Comparative Examples 4 to 8), a water-in-oil (W / O type) emulsion was used. Even if it is not obtained or the polyester resin powder is formed, the specific gravity is 0.6
It was as high as 5 to 0.91 and only a large pore diameter on the particle surface and a large vesicle diameter inside the particle were obtained.

The electron micrographs shown in FIGS. 1 to 6 also show that fine pores are uniformly formed inside the particles of Example 2 and Example 4 according to the present invention. Further, it can be seen that fine pores with small irregularities are uniformly formed on the surface of these particles.

As is clear from the above, according to the present invention, an unsaturated polyester is used as an unsaturated polyester, and an alkali metal hydroxide, carbonate and / or bicarbonate is used as a base. ,
It is possible to produce a polyester resin powder having a sufficiently low specific gravity as a lightening material and having uniformly formed fine pores.

Further, according to the present invention, fine pores are uniformly formed on the particle surface and inside the particle. Therefore, even when mixed with a liquid substance such as water, plasticizer, mineral oil, etc. The liquid material is less likely to be absorbed, and is optimal as a lightweight material to be mixed into the liquid material.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing the internal structure of particles of a porous polyester resin powder produced in Example 2 according to the present invention.

FIG. 2 is an electron micrograph showing the structure of the particle surface of the porous polyester resin powder produced in Example 2 according to the present invention.

FIG. 3 is an electron micrograph showing the internal structure of the particles of the porous polyester resin powder produced in Example 4 according to the present invention.

FIG. 4 is an electron micrograph showing the structure of the particle surface of the porous polyester resin powder produced in Example 4 according to the present invention.

FIG. 5 is an electron micrograph showing the internal structure of the particles of the porous polyester resin powder produced in Comparative Example 6.

FIG. 6 is an electron micrograph showing the structure of the particle surface of the porous polyester resin powder produced in Comparative Example 6.

Continuation of the front page (56) References JP-A-5-148384 (JP, A) JP-A-3-81313 (JP, A) JP-A-6-313021 (JP, A) JP-A-4-227647 (JP) JP-A-61-118434 (JP, A) JP-B-50-17115 (JP, B1) JP-B-49-13330 (JP, B1) JP-B-48-34820 (JP, B1) 49-41331 (JP, B1) JP-B-48-12195 (JP, B1) JP-B-44-31831 (JP, B1) JP-B-44-8747 (JP, B1) JP-B-40-28948 (JP, B1) B1) Special Table 56-561731 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 283/00-283/01 C08F 290/00-290/14 C08F 2/32 C08J 9/28 C08L 67/00-67/06

Claims (1)

(57) [Claims] 1. An aqueous solution of a base is dispersed in an oil phase comprising an unsaturated polyester and a polymerizable monomer, and the dispersion is re-dispersed in an aqueous solution of a suspension stabilizer, crosslinked and cured, and dried. The method for producing a porous polyester resin powder by using, as the unsaturated polyester, an isophthalic unsaturated polyester, and as the base, a hydroxide, a carbonate, and / or a bicarbonate of an alkali metal, The amount of the base added is 0.1 to the acid value of the unsaturated polyester.
A method for producing a lightweight polyester resin powder, wherein the amount is from 0.5 to 0.8 equivalent.