JPH0561302B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for improving powder properties of synthetic resin powder. More specifically, the present invention involves adding fine powder after coagulation of a graft copolymer latex having rubber as a backbone polymer to obtain a synthetic resin powder having excellent powder characteristics. Regarding improvement methods. [Prior Art] Various methods for improving the powder properties of synthetic resin powder have been studied. For example, a method for coagulating copolymer latex in a vapor phase (Japanese Patent Application Laid-open No. 1983-
59929), a method of direct spray drying, and a method of coagulating after spherical dispersion in a specific solvent are known. [Problems to be Solved by the Invention] However, the conventionally known methods as described above are insufficiently effective in improving powder properties, and the recent increase in the size of automatic powder weighing and transportation methods The drawback is that powders with flowability and anti-blocking properties cannot be obtained. Therefore, the present inventors believed that improvement of powder properties is essential for automatic powder metering and larger transportation methods, and as a result of extensive research, they have completed the present invention. [Means for Solving the Problem] That is, the present invention coagulates a graft copolymer having rubber as a backbone polymer, and adds Si, Mg, and Al having an average particle size of 10 μm or less to 100 parts by weight of the copolymer. ，
At least one fine powder of one or more oxides, chlorides, carbonates and sulfates of metals selected from the group consisting of Ca, Ba, Zn and Ti 0.001
The present invention relates to a method for improving powder properties of synthetic resin powder, which comprises adding up to 10 parts by weight. [Example] The graft copolymer used in the present invention can be prepared by first producing a rubber serving as a backbone polymer by ordinary emulsion polymerization, and then copolymerizing the obtained copolymer latex with the copolymer latex. It can be obtained by graft copolymerizing monomers using conventional emulsion polymerization. Examples of rubber-forming monomers used as the backbone polymer include diene monomers such as butadiene, isoprene, and chloroprene;
Alternatively, acrylic acid alkyl ester monomers such as butyl acrylate and octyl acrylate are used. In addition, the carbon number of the acrylic acid alkyl ester monomer is 4 to 11, especially 5 to 7.
It is preferable that Furthermore, the monomer may be copolymerized with a copolymerizable monomer. Examples of such copolymerizable monomers include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, vinyl cyanogens such as acrylonitrile and methacrylonitrile, styrene,
Examples include aromatic vinyl such as α-methylstyrene, and halogenated vinyl such as vinyl chloride and vinyl bromide. Furthermore, divinylbenzene, monoethylene glycol dimethacrylate,
Although polyethylene glycol dimethacrylate and the like can be used, the present invention is not limited to such specific examples. Particularly preferred rubbers contain 20 to 80 parts by weight of butadiene, 0 to 50 parts by weight of styrene, 0 to 20 parts by weight of a monomer copolymerizable with butadiene or styrene, and 0 to 5 parts by weight of a crosslinking agent, based on 100 parts by weight of the total amount. obtained by emulsion polymerization. Next, monomers used when graft copolymerizing the rubber as a backbone polymer to obtain a copolymer include alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, and octyl acrylate, which are copolymerizable with the rubber. ; Acrylic methacrylates such as methyl methacrylate and ethyl methacrylate; Vinyl cyanide such as acrylonitrile and methacrylonitrile; Aromatic vinyls such as styrene and α-methylstyrene; Vinyl halides such as vinyl chloride and vinyl bromide, divinylbenzene, and monoethylene Examples include crosslinking agents such as glycol dimethacrylate and polyethylene glycol dimethacrylate. The fine powder used in the present invention includes Si, Mg,
Specific examples include oxides, chlorides, carbonates, and sulfates of one or more metals selected from the group consisting of Al, Ca, Ba, Zn, and Ti. For example,
SiO ₂ , MgO, MgCO ₃ , Al ₂ O ₃ , Al ₂ (CO ₃ ) ₃ ,
Examples include CaO, CaCO ₃ , TiO ₂ , talc, clay, diatomaceous earth, and calcium metasilicate.
Note that these compounds may be natural products or synthetic products. The average particle size of the fine powder is 10 μm or less,
The smaller the particle size, the greater the effect of improving the powder characteristics of the powder, so it is preferable. When the average particle size exceeds 10 μm, the effect of improving powder properties is small. Further, the fine powder is added in an amount of 0.001 to 10 parts by weight per 100 parts by weight of a copolymer having coagulated rubber as a backbone polymer. If the amount of fine powder added is less than 0.001 part by weight, the effect of improving powder properties is small, and if it exceeds 10 parts by weight, the original physical properties of the synthetic resin will deteriorate. The composition of the copolymer obtained by the graft copolymerization is 5 to 80 parts by weight of the rubber component and 20 to 95 parts by weight of the graft component based on 100 parts by weight of the total amount of the copolymer, and the monomer content in the graft part is The proportions are 30 to 70 parts by weight of methyl methacrylate, 30 to 70 parts by weight of styrene, 0 to 20 parts by weight of other copolymerizable monomers, and 0 to 5 parts by weight of crosslinking agent, based on 100 parts by weight of the total amount of the graft part. Preferably. In the present invention, coagulants used in coagulating the graft copolymer include inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, and nitric acid, organic acids such as acetic acid, so-called alkali metal halides such as sodium and potassium, and inorganic acids. Alkali metal salts with organic acids or alkali metal salts with organic acids are used. These can be used alone or in combination of two or more.
0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight of the coagulant as described above is added to 100 parts by weight of the copolymer latex, and a coagulation operation is carried out. After coagulating the graft copolymer, the average particle size
The fine powder of 10 μm or less is a solidified copolymer.
It is added in a proportion of 0.001 to 10 parts by weight per 100 parts by weight. The fine powder is added after solidification, after heat treatment,
Although it may be carried out either after dehydration or drying, it is preferable to add it to the powder after dehydration or drying, as it is more effective. Hereinafter, the method for improving the powder properties of synthetic resin powder according to the present invention will be explained based on Examples, but the present invention is not limited to these Examples. Example 1 200 parts by weight of water, 1.5 parts by weight of sodium oleate, 0.002 parts by weight of ferrous sulfate, 0.005 parts by weight of ethylenediaminetetraacetic acid disodium salt, tripotassium phosphate
0.2 parts by weight, 0.2 parts by weight of sodium formaldehyde sulfoxylate, 75 parts by weight of butadiene, 25 parts by weight of styrene, 1.0 parts by weight of divinylbenzene, and diisopropylbenzene hydroperoxide.
0.1 part by weight was charged into a polymerization vessel with an internal volume of 5 and equipped with a stirrer, and polymerization was carried out at a reaction temperature of 50°C for 5 hours. The polymerization conversion rate of the obtained rubber was 98%. Next, 180 parts by weight of the obtained rubber (solid content 60 parts by weight), water
90 parts by weight, 0.002 parts by weight of ferrous sulfate, 0.004 parts by weight of ethylenediaminetetraacetic acid disodium salt, 0.1 parts by weight of sodium formaldehyde sulfoxylate,
20 parts by weight of styrene and 20 parts by weight of methyl methacrylate were placed in a polymerization vessel with an internal volume of 5 and equipped with a stirrer.
Polymerization was carried out at a reaction temperature of 60°C for 3 hours. The polymerization conversion rate of the obtained copolymer was 99%. 300 ml of 10% hydrochloric acid was added to the obtained copolymer latex 3 (100 parts by weight of the graft copolymer) to coagulate it, followed by dehydration and drying to obtain a synthetic resin powder. The powder properties were improved by adding 0.5 parts by weight of fine powder of titanium oxide (manufactured by Nippon Aerosil Co., Ltd., product number: Titanium Oxide P25, average particle size: 0.03 μm) to 100 parts by weight of the resulting synthetic resin powder. Obtained synthetic resin powder. The powder characteristics of the obtained synthetic resin powder, such as fluidity index, disintegration, and shear load, were investigated according to the following methods. The results are shown in Table 1. (Fluidity Index) Chemical Engineering
Engineering), January 18, 1965, Daily Edition, pp. 163-168, the four measured values of angle of repose, degree of compaction, angle of spatierla, and degree of uniformity (or degree of agglomeration) were obtained for the obtained synthetic resin powder, Scores were assigned based on these values according to a conversion table, and evaluation was made using an index expressed as the sum of these scores. Note that the larger the measured value, the better the fluidity. (Disintegrability) A certain load (5 kg/
cm ² ) and block (shape: cylindrical, dimensions: 5
cmφ x 3cm), the block is subjected to constant vibration (frequency: 60Hz) for 100 seconds to disintegrate it, and the weight of the powder of 18 mesh passes among the disintegrated powder is calculated as a percentage of the total weight of the original block. It was expressed as The percentage value is called disintegrability (unit: %), and the larger the value, the more difficult it is to block. (Shear load) Powder bed tester (manufactured by Sankyo Dengyo Co., Ltd.)
PTO type) is filled with synthetic resin powder,
A one-sided shear test was conducted under a constant load (20 Kg/cm ² ). The maximum shearing load (unit: Kg) at that time was expressed as a blocking index of the resin. That is, the larger the value, the easier it is to block. Example 2 Calcium carbonate (manufactured by Shiraishi Calcium Co., Ltd., trade name: Shiroenka CCR, average particle size: 0.08 μm) was added to 100 parts by weight of the synthetic resin powder obtained in Example 1, instead of using titanium oxide as a fine powder. ) A synthetic resin powder with improved powder properties was obtained in the same manner as in Example 1, except that 0.5 part by weight was used. The powder characteristics of the obtained synthetic resin powder, such as fluidity index, disintegration, and shear load, were measured in the same manner as in Example 1. The results are shown in Table 1. Example 3 Silicon oxide (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil #2, average particle size: 0.01) was added to 100 parts by weight of the synthetic resin powder obtained in Example 1 instead of using titanium oxide as a fine powder. A synthetic resin powder with improved powder properties was obtained in the same manner as in Example 1, except that 0.5 parts by weight (μm) was used. The powder characteristics of the obtained synthetic resin powder, such as fluidity index, disintegration, and shear load, were measured in the same manner as in Example 1. The results are shown in Table 1. Example 4 Instead of using tyrane oxide as a fine powder in 100 parts by weight of the synthetic resin powder obtained in Example 1, aluminum oxide (manufactured by Nippon Aerosil Co., Ltd., trade name: Aluminum Oxide C, average particle size: 0.02) μm) 0.5
A synthetic resin powder with improved powder properties was obtained in the same manner as in Example 1 except that parts by weight were used. The powder properties of the obtained synthetic resin powder include the fluidity index,
The collapsibility and shear load were measured in the same manner as in Example 1. The results are shown in Table 1. Example 5 To 100 parts by weight of the synthetic resin powder obtained in Example 1, instead of using titanium oxide as a fine powder, barium chloride (separated product manufactured by Wako Pure Chemical Industries, Ltd., average particle size: 0.5 μm) was added. A synthetic resin powder with improved powder properties was obtained in the same manner as in Example 1 except that 0.001 part by weight was used. The powder characteristics of the obtained synthetic resin powder, such as fluidity index, disintegration, and shear load, were measured in the same manner as in Example 1. The results are shown in Table 1. Example 6 100 parts by weight of the synthetic resin powder obtained in Example 1 was classified with zinc chloride (manufactured by Wako Pure Chemical Industries, Ltd.) instead of using titanium oxide as a fine powder (average particle size: 1 μm). A synthetic resin powder with improved powder properties was obtained in the same manner as in Example 1 except that 10 parts by weight was used. Example 1: Fluidity index, disintegration, and shear load were measured as powder properties of the obtained synthetic resin powder.
It was measured in the same manner. The results are shown in Table 1. Example 7 Instead of using titanium oxide with an average particle size of 0.03 μm as a fine powder to 100 parts by weight of the synthetic resin powder obtained in Example 1, a mixture with an average particle size of 10 μm [based on 100 parts by weight of the entire mixture] Barium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was classified using
m) 0.25 parts by weight and 0.25 parts by weight of classified zinc chloride (manufactured by Wako Pure Chemical Industries, Ltd.) (average particle size: 10 μm)] Powder was prepared in the same manner as in Example 1, except that 0.5 parts by weight were used. A synthetic resin powder with improved physical properties was obtained. The powder characteristics of the obtained synthetic resin powder, such as fluidity index, disintegration, and shear load, were measured in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 The powder properties of the synthetic resin powder itself obtained in Example 1, such as fluidity index, disintegration, and shear load, were measured in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 2 In 100 parts by weight of the synthetic resin powder obtained in Example 1, instead of using titanium oxide as a fine powder, calcium carbonate (manufactured by Shiraishi Calcium Co., Ltd., product name: Shiroenka CCR, average particle size: 0.08 μm) ) A synthetic resin powder was obtained in the same manner as in Example 1 except that 0.005 part by weight was used. The powder characteristics of the obtained synthetic resin powder, such as fluidity index, disintegration, and shear load, were measured in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 3 Instead of using titanium oxide with an average particle size of 0.03 μm as a fine powder in 100 parts by weight of the synthetic resin powder obtained in Example 1, a mixture with an average particle size of 15 μm [based on 100 parts by weight of the entire mixture] Barium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was classified using
m) 0.25 parts by weight and 0.25 parts by weight of classified zinc chloride (manufactured by Wako Pure Chemical Industries, Ltd.) (average particle size: 15 μm)] Synthesized in the same manner as in Example 1 except that 0.5 parts by weight were used. I got resin powder. The powder characteristics of the obtained synthetic resin powder, such as fluidity index, disintegration, and shear load, were measured in the same manner as in Example 1. The results are shown in Table 1.

[Table] [Effects of the Invention] According to the present invention, the fluidity and blocking resistance of synthetic resin powder can be significantly improved compared to when conventionally known methods are used. Therefore, it is possible not only to eliminate blocking phenomena and clogging of transportation lines during storage of synthetic resin powder, but also to enable automatic weighing and transportation of powders on a larger scale.

Claims (1)

[Claims] 1. Coagulate a graft copolymer latex with rubber as the backbone polymer, and add Si, Mg, Al, Ca,
Fine powder of at least one oxide, chloride, carbonate and sulfate of one or more metals selected from the group consisting of Ba, Zn and Ti 0.001 to 10
A method for improving powder characteristics of a synthetic resin powder, characterized by adding parts by weight.