JP2003041147A - Coated zinc oxide particle, method for producing the same and application thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain zinc oxide particles having excellent dispersibility in a resin and a thermoplastic resin composition containing the particles having excellent visible light transparency and ultraviolet light shielding property and a molding thereof and to provide a method for producing them. SOLUTION: This thermoplastic resin composition having excellent visible light transparency and ultraviolet light shielding property is obtained by adding zinc oxide particles in which the surfaces of zinc oxide particles are coated with a metallic soap to a resin. This molding is obtained. The zinc oxide particles in which the surfaces of zinc oxide particles are coated with a metallic soap are obtained by mixing the metallic soap with the zinc oxide particles at the melting point of the metallic soap or above.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to zinc oxide used in resin products, rubber products, papers, cosmetics, pharmaceutical preparations, paints, printing inks, ceramic products, electronic parts, etc., and particularly in resins. TECHNICAL FIELD The present invention relates to coated zinc oxide particles having good dispersibility, a thermoplastic resin composition using the particles, which has excellent transparency in visible light and ultraviolet ray shielding properties, a molded article thereof, and a method for producing the same.

[0002]

2. Description of the Related Art Zinc oxide has been known as a white pigment for a long time as it is called zinc white. When the particle size of such zinc oxide is reduced to about 1/2 of the visible light wavelength, the scattering effect of the zinc oxide particles becomes extremely small and visible light is transmitted, but zinc oxide has excellent ultraviolet absorption. It has an optical characteristic that it selectively absorbs ultraviolet rays due to its effect.

Conventionally, as ultraviolet absorbers, benzophenone type, benzotriazole type, salicylate type,
Organic UV absorbers such as substituted acrylonitrile are known, but there are restrictions for safe use.
When it is added to a thermoplastic resin or the like, there is a problem that it is decomposed during molding or bleeds out due to its poor heat resistance. For these reasons, zinc oxide particles, which are excellent in safety and have high heat resistance, are drawing attention as a substitute for organic UV absorbers.

An ultraviolet absorber using such zinc oxide particles is disclosed in Japanese Patent Application Laid-Open No. 5-171130.
A resin molded body has been proposed in which zinc oxide fine powder having a particle size of 0.1 μm or less is added to a transparent resin. In addition, JP-A-5-29
5141 and Japanese Patent Application Laid-Open No. 11-302015 propose zinc oxide fine particles coated with a silicon compound in order to improve weather resistance deterioration due to photocatalytic action of zinc oxide fine particles and to improve dispersibility in a resin.

Further, in Japanese Patent Publication No. 2501663 (International Publication WO 90/06974), a saturated or unsaturated monocarboxylic acid having 7 to 22 carbon atoms is added to a slurry containing a zinc oxide composition for pigments. Water-soluble alkali metal salts of acids and IB, II, II of the periodic table of the elements
A metal cation selected from the group of I, IV, V, VIB, VIIB and VIII and a water-soluble metal salt consisting of an inorganic anion moiety selected from the group consisting of nitrate, sulfate and halogen ions, A method is proposed in which formation and precipitation of a water-insoluble metal soap of the saturated or unsaturated monocarboxylic acid is performed in situ, and the zinc oxide composition for pigment is encapsulated with a coating in which the water-insoluble metal soap is deposited. Has been done.

Further, the method of using a solvent (for example, water, an organic solvent, etc.) during the surface treatment requires steps such as filtration and drying of the solvent, and uneven distribution of the surface treatment agent or agglomeration of the powder which precipitates during the drying occurs. It is easy to happen. Therefore, this method has a disadvantage that it is difficult to obtain good dispersibility of the coated zinc oxide particles.

[0007]

However, the conventional zinc oxide particles obtained by these methods or the like are highly agglomerated and it is difficult to uniformly disperse them in the resin, and the resin composition thereof becomes cloudy. , It was not always possible to obtain sufficient transparency.

In the present invention, coated zinc oxide particles having good dispersibility in a resin, a thermoplastic resin composition containing the particles and having excellent visible light transparency and ultraviolet ray shielding properties, a molded article thereof,
And a method for producing them.

[0009]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventor has achieved the above object by coating zinc oxide particles with a metallic soap.

That is, the present invention comprises the following inventions. (1) A method for producing particles in which zinc oxide particles are coated with a metal soap, wherein the metal soap and the zinc oxide particles are mixed at a temperature equal to or higher than the melting point of the metal soap. . (2) Coated zinc oxide particles produced by the production method according to the above 1, which are particles obtained by coating zinc oxide particles with a metal soap. (3) The average primary particle diameter of zinc oxide is 0.005 to 0.1
3. The coated zinc oxide particle according to the above item 2, which is μm. (4) The coated zinc oxide particles according to the above 2 or 3, wherein the metal soap is a fatty acid salt of at least one metal selected from the group consisting of magnesium, zinc, barium, calcium and aluminum. (5) The metal soap is a metal salt of at least one fatty acid selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, behenic acid, montanic acid, and derivatives thereof. 5. The coated zinc oxide particles according to any one of items 2 to 4 above. (6) The coated zinc oxide particles according to the above 2 or 3, wherein the metal soap is at least one selected from the group consisting of zinc stearate, magnesium stearate, and calcium stearate. (7) The coated zinc oxide particles according to any one of items 2 to 6 above, wherein the zinc oxide particles are particles having a siloxane bond on the surface.

(8) A thermoplastic resin composition comprising the coated zinc oxide particles according to any one of items 2 to 7 above. (9) The thermoplastic resin composition according to the above item 8, which is a compound or a masterbatch. (10) The thermoplastic resin composition according to item 8, wherein the concentration of zinc oxide particles in the thermoplastic resin composition is in the range of 0.01 to 80% by mass based on the total mass of the composition.

(11) A molded product obtained by molding the thermoplastic resin composition as described in any one of the above items 8 to 10. (12) The molded article is at least one kind selected from the group consisting of fibers, films, and plastics.
The molded article according to.

(13) The above item 8 which is characterized in that the coated zinc oxide particles according to any one of the items 2 to 7 are used.
11. The method for producing the thermoplastic resin composition according to any one of items 1 to 10. (14) The method for producing a molded article according to item 11 or 12, wherein the thermoplastic resin composition according to any one of items 8 to 10 is used.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The metal soap used in the present invention refers to a fatty acid salt having 10 or more carbon atoms among fatty acid salts containing a metal element. As these metal soaps, for example, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, behenic acid,
Examples thereof include metal salts such as montanic acid and derivatives thereof. Examples of the element of these metal salts include magnesium, zinc, barium, calcium, aluminum and the like. Among these, as a metal soap having a large effect of improving dispersibility in the resin, among these,
Examples of metal soaps that are industrially readily available and have a large effect of improving dispersibility in a resin include zinc stearate, magnesium stearate, and calcium stearate. These can be preferably used in the present invention. .

Next, the zinc oxide particles used in the present invention are not particularly limited as long as they contain zinc oxide as a main component and have the above-mentioned optical characteristics. The method for producing zinc oxide used as a raw material in the present invention is not particularly limited, and may be obtained by any of the French method, the American method and the wet method. The average particle size of the primary particles of zinc oxide is preferably 0.001 to 0.2 μm, and particularly preferably 0.005 to 0.1 μm.
If the average particle size of the primary particles is 0.001 μm or less, it is difficult to produce it efficiently, and if it exceeds 0.2 μm, sufficient transparency of the resin containing the coated zinc oxide particles is obtained. Is difficult to obtain.

In order to impart functions such as weather resistance and conductivity to the resin containing zinc oxide particles, surface-treated zinc oxide particles can be used as a raw material in the present invention. For example, zinc oxide particles having a siloxane bond on the surface thereof may be used for the purpose of enhancing weather resistance when added to the resin. Examples of zinc oxide having these siloxane bonds include zinc oxide particles coated with silica, silicone, alkoxysilane and the like. The coating method for these is not particularly limited, but it is a method of dry mixing in the presence of silicone or alkoxysilane, or zinc oxide particles are added to an aqueous solution of sodium silicate, neutralized with hydrochloric acid or sulfuric acid, and filtered. , Washing and drying.

The coated zinc oxide particles of the present invention can be obtained by mixing the metal soap and the zinc oxide particles at a temperature equal to or higher than the melting point of the metal soap by, for example, a high speed mixer. By mixing above the melting point of the metal soap, the metal soap is uniformly coated on the surface of the zinc oxide particles.

At a temperature lower than the melting point of the metal soap, it is difficult to uniformly coat the surface of the zinc oxide particles, and it is difficult to improve the dispersibility in the resin. As the coating amount of zinc oxide particles of the metal soap, for example, when added to the resin described below,
0.1 mass% to 50 mass% is preferable, and 1 mass% to 20
Mass% is more preferable. When it is less than 0.1% by mass, the dispersibility in the resin is not good, while when it is more than 50% by mass, there is a problem of bleed-out and oil smoke during molding.

When the coated zinc oxide particles and the thermoplastic resin are melt-kneaded and pelletized by a twin-screw kneading extruder, the smaller the extrusion pressure rises, the better the coated zinc oxide particles are in the resin. It is judged that it is showing. For example, 22 parts by mass of coated zinc oxide particles, low density polyethylene (manufactured by Nippon Polyolefin Co., Ltd., J-LEX JH607C) 78
15 mm small twin-screw kneading extruder (KZW15)
-30MG, manufactured by Techno Bell Co., Ltd., is melt-kneaded at a kneading temperature of 150 ° C. and a protrusion amount of 1 kg / hr to be pelletized, a diameter of 1 mmφ, a length of 3 to 5 mm, and a mass of 0.0
1 kg of low density polyethylene compound containing 03-0.01 g of cylindrical zinc oxide particles is prepared.
In preparing the compound, a breaker plate of a twin-screw kneading extruder is fitted with a 45 μm stainless mesh. When 1 kg of the compound is produced in this manner, the extrusion pressure rise is 5 MPa or less, preferably 2 MPa or less when the coated zinc oxide particles of the present invention are used.

The zinc oxide particles in the present invention can be used as a thermoplastic resin composition by adding them to a thermoplastic resin. Specific examples of such a thermoplastic resin include polyethylene, polypropylene, polystyrene, polyethylene terephthalate, AS resin, ABS resin, AES resin, polyvinylidene chloride, methacrylic resin, polyvinyl chloride, polyamide, polycarbonate, polyallyl ester. , Polyimide, polyacetal, polyether ketone, polyether sulfone, polyphenyl oxide, polyphenylene sulfide and the like.

These thermoplastic resin compositions containing the zinc oxide particles of the present invention can be used in the form of compounds, masterbatches and the like. The concentration of zinc oxide particles in the thermoplastic resin composition is 0.01 to 80% by mass, preferably 1 to 50% by mass, based on the total mass of the composition. In addition, additives such as an antioxidant and an antistatic agent may be added to the thermoplastic resin composition.

In the present invention, a molded article having an ultraviolet shielding ability can be obtained by molding the thermoplastic resin composition. As a molded article of such a composition, a fiber,
Examples thereof include films and plastic moldings.

Further, the molded product of the present invention may be provided as a part of the structure. Such a structure is not particularly limited, for example, may be composed of an inorganic material such as metal, concrete, glass, pottery, paper,
It may be made of an organic material such as plastic, wood, or leather. Alternatively, a combination of them may be used. Examples of these include, for example, packaging materials, building materials, machines, vehicles, glass products, home appliances, agricultural materials, electronic devices, tools, tableware, bath products, toilet products, furniture, clothing, cloth products, textiles, leather products, Paper products, sports equipment, groups, containers, glasses, signs, piping, wiring, metal fittings, sanitary materials,
Examples include automobile articles, tents, stockings, socks, gloves and masks.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples.

Example 1 Zinc oxide particles having a primary particle size of 0.03 μm (UFZ-, manufactured by Showa Titanium Co., Ltd.)
40) 20 kg and zinc stearate (NOF Corporation)
Made, zinc stearate S, melting point 120 ° C) 2 kg 3
The mixture was put into a 00-liter high-speed stirring mixer (Super mixer SMG-300 manufactured by Kawata Co., Ltd.). Next, the blades were mixed at a peripheral speed of 20 m / sec, externally heated by steam, and heated and mixed until the powder temperature reached 140 ° C. Next, the powder was naturally cooled to obtain zinc oxide particles coated with zinc stearate.

Next, 22 parts by mass of zinc oxide particles coated with zinc stearate and 78 parts by mass of low-density polyethylene (J-LEX JH607C manufactured by Nippon Polyolefin Co., Ltd.) were used as a small biaxial kneading extruder (KZW15-3) of 15 mm.
Kneading temperature 15 using 0MG, manufactured by Techno Bell Co., Ltd.
Melt kneading at 0 ° C. and protrusion amount 1 kg / hr to pelletize, diameter 1 mmφ, length 3-5 mm, mass 0.003
1 kg of low density polyethylene compound containing ~ 0.01 g of cylindrical zinc oxide particles was made. In making the compound, a 45 μm stainless mesh was attached to the breaker plate of the twin-screw kneading extruder, and the pressure rise when 1 kg of the compound was made was examined, but the pressure rise was small at 0.5 MPa and was coated with zinc stearate. The zinc oxide particles were found to be well dispersed in low density polyethylene.

Next, 200 g of the low-density polyethylene compound containing the zinc oxide particles obtained above and 1800 g of low-density polyethylene (manufactured by Nippon Polyolefin Co., Ltd., J-LEX JH607C) were mixed with a V-type blender (manufactured by Ikemoto Rika Kogyo Co., Ltd.). , RKI-40) for 10 minutes,
Mixed pellets were made.

Next, 200 mm of the obtained mixed pellets
Small twin-screw kneading extruder with T-die (KZW15-3
A film having a thickness of 80 μm was prepared with a die temperature of 250 ° C. using 0MG, manufactured by Technovel Co., Ltd. The obtained low-density polyethylene film was spectrophotometer (manufactured by Shimadzu Corporation, UV-2).
The transmittance was measured with 400 PC. As a result, as shown in Table 1, the transmittance at 360 nm was 0% and 550 n.
The transmittance at m was 90%. When the polyethylene film becomes cloudy and the transparency is lowered, the transmittance in the visible region is lowered, and thus the light transmittance at 550 nm is an index of the transparency.

Example 2 Except that the zinc stearate in Example 1 was calcium stearate (produced by NOF CORPORATION, calcium stearate S, melting point 152 ° C.), and the heating and mixing temperature in the high speed stirring mixer was 160 ° C. Was processed in the same manner as in Example 1, and the results shown in Table 1 were obtained.

Example 3: The zinc stearate used in Example 1 was replaced by magnesium stearate (manufactured by NOF CORPORATION).
Magnesium stearate, melting point 123 ° C.), and the same treatment as in Example 1 except that the heating and mixing temperature in the high-speed stirring mixer was 140 ° C., and the results in Table 1 were obtained.

Example 4: The zinc stearate used in Example 1 was replaced with magnesium behenate (manufactured by Eishin Kasei Co., Ltd., MS).
The same treatment as in Example 1 was performed except that the temperature was set to -7 and the melting point was 116 ° C), and the results shown in Table 1 were obtained.

Example 5: The zinc stearate used in Example 1 was replaced with zinc laurate (ZS-manufactured by Nitto Kasei Co., Ltd.).
3, the melting point was 130 ° C.), and the same treatment as in Example 1 was performed, and the results shown in Table 1 were obtained.

Example 6: Zinc oxide particles having a primary particle diameter of 0.03 μm (UFZ-, manufactured by Showa Titanium Co., Ltd.)
40) 20 kg of 300 L high speed stirring mixer (Co., Ltd.)
It was put into a super mixer SMG-300 manufactured by Kawata and stirred at a blade peripheral speed of 10 m / sec. Next, a silicone having a siloxane bond (AFP-, manufactured by Shin-Etsu Chemical Co., Ltd.)
1) 600 g was sprayed onto the zinc oxide particles in the mixer using a two-fluid nozzle. Then, the peripheral speed of the blades was set to 20 m / sec and external heating was performed by steam, and the powder temperature was adjusted to 140
The mixture was heated and mixed until the temperature reached ℃. Next, the powder was naturally cooled to obtain zinc oxide particles coated with silicone. After the obtained zinc oxide particles coated with silicone were coated with zinc stearate in the same manner as in Example 1, a low density polyethylene film containing zinc oxide particles was prepared in the same manner as in Example 1 and I got the result.

Comparative Example 1: Zinc oxide particles having a primary particle diameter of 0.03 μm (UFZ-, manufactured by Showa Titanium Co., Ltd.)
No. 40) was not coated with zinc stearate, a low density polyethylene film containing zinc oxide particles was produced in the same manner as in Example 1, and the results in Table 1 were obtained.

Comparative Example 2: The zinc oxide particles coated with silicone in Example 4 were not coated with zinc stearate, and a low density polyethylene film containing zinc oxide particles was prepared in the same manner as in Example 1. The results shown in Table 1 were obtained.

Comparative Example 3: The same treatment as in Example 1 was carried out except that the heating and mixing temperature of the high-speed stirring mixer was 100 ° C., and the results shown in Table 1 were obtained.

Comparative Example 4: Zinc oxide particles having a primary particle diameter of 0.03 μm (UFZ-, manufactured by Showa Titanium Co., Ltd.)
40) 400 g, zinc stearate (NOF CORPORATION)
Made, zinc stearate S, melting point 120 ° C.) 40 g,
1560 g of low-density polyethylene (manufactured by Nippon Polyolefin Co., Ltd., J-LEX JH607C) was mixed with a V-type blender (manufactured by Ikemoto Rika Kogyo Co., Ltd., RKI-40) for 10 minutes. After the obtained mixture was kneaded with a small twin-screw extruder in the same manner as in Example 1, a low density polyethylene film containing zinc oxide particles was produced in the same manner as in Example 1, and the results in Table 1 were obtained.

Comparative Example 5: 1 low density polyethylene (J-Lex JH607C manufactured by Nippon Polyolefin Co., Ltd.)
Small 5 mm twin-screw kneading extruder (KZW15-30MG,
(Manufactured by Techno Bell Co., Ltd.) is melt-extruded at a kneading temperature of 150 ° C. and an amount of protrusion of 1 kg / hr to pelletize, and the diameter is 1 mmφ, the length is 3 to 5 mm, and the mass is 0.003 to.
1 kg of 0.01 g of cylindrical pellets was made. At the time of pelletization, as in Example 1, a breaker plate of a twin-screw kneading extruder was equipped with a 45 μm stainless mesh to examine the pressure rise.

Next, the low-density polyethylene pellets obtained above were converted into a small twin-screw kneading extruder having a 200 mm T-die (KZW15-30MG, manufactured by Technovel Co., Ltd.).
With the die temperature of 250 ° C., a film having a thickness of 80 μm was produced. The transmittance of the obtained low-density polyethylene film was measured with a spectrophotometer (UV-2400PC, manufactured by Shimadzu Corporation), and the results shown in Table 1 were obtained.

Comparative Example 6: Zinc oxide particles having a primary particle size of 0.03 μm (UFZ-, manufactured by Showa Titanium Co., Ltd.)
40) To a slurry containing 20 kg and 180 kg of water was added 80 L of an aqueous solution containing 2 kg of sodium stearate at 85 ° C. Furthermore, 40 L of an aqueous solution containing 1.2 kg of zinc nitrate was added to the slurry, and 5 N-
The pH was adjusted to a value of 7 with NaOH solution. The slurry was then filtered, washed, dried at 105 ° C. overnight and ground. The recovered powder contained 10% by weight zinc stearate. Next, using this powder, a low density polyethylene film containing zinc oxide particles was produced in the same manner as in Example 1, and the results shown in Table 1 were obtained.

Comparative Example 7: To 200 liters of benzene, 2 kg of zinc stearate (manufactured by NOF CORPORATION, zinc stearate S, melting point 120 ° C.) was added and dissolved, and a primary particle diameter of 0.03 μm was added thereto. 20 kg of zinc oxide particles (UFZ-40, manufactured by Showa Titanium Co., Ltd.) having therein were added. Next, this slurry was dried with a spray dryer (DCDA28-50N manufactured by Sakamoto Giken Co., Ltd.) and then pulverized. Using this powder, a low density polyethylene film containing zinc oxide particles was produced in the same manner as in Example 1, and the results shown in Table 1 were obtained.

[0042]

[Table 1]

[0043]

EFFECTS OF THE INVENTION Coated zinc oxide particles having good dispersibility in a resin by coating them with a metallic soap, a compound containing the particles, which is excellent in transparency to visible light and ultraviolet ray shielding property, and It is possible to provide a thermoplastic resin composition such as a masterbatch, a molded article of the above-mentioned thermoplastic resin composition such as a fiber, a film, and a plastic, and a method for producing them.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 101/00 C08L 101/00 C09C 3/08 C09C 3/08 // B29K 101: 12 B29K 101: 12 105 : 16 105: 16 305: 00 305: 00 (72) Inventor Hisao Okoi 3-1, Nishinomiyacho, Toyama City, Toyama Prefecture Showa Titanium Co., Ltd. F-term (reference) 4F070 AA13 AA15 AA18 AA19 AA32 AA42 AA47 AA50 AA52 AA54 AA55 AA58 AB08 AB09 AB11 AC13 AC40 AD06 AE01 FA03 FB03 FB04 FC05 4F071 AA02 AB18 AC09 AE05 AE17 AG12 AH03 AH04 AH05 AH07 AH11 AH12 AH16 BA01 BB06 BC25 A01 A25 A01 A25 A01 A25 A15 A25 A13 A25 A4 BB031 BB121 BC031 BC061 BD041 BD101 BG061 BN061 BN151 CB001 CF061 CG001 CH071 CH091 CL001 CM041 CN011 CN031 DE106 FB236 GG00 GK00 GL00 GN00 GQ00 4J037 AA 11 CB09 EE03 EE28 FF02 FF15

Claims (14)

[Claims] 1. A method for producing particles in which zinc oxide particles are coated with a metal soap, wherein the metal soap and the zinc oxide particles are mixed at a temperature equal to or higher than the melting point of the metal soap. Production method. 2. Coated zinc oxide particles produced by the method according to claim 1, which are particles obtained by coating zinc oxide particles with a metal soap. 3. The average primary particle diameter of zinc oxide is 0.005.
The coated zinc oxide particles according to claim 2, wherein the coated zinc oxide particles have a size of 0.1 μm. 4. The coated zinc oxide particles according to claim 2 or 3, wherein the metal soap is a fatty acid salt of at least one metal selected from the group consisting of magnesium, zinc, barium, calcium and aluminum. 5. A metal soap comprising lauric acid, myristic acid,
The metal salt of at least one fatty acid selected from the group consisting of palmitic acid, stearic acid, isostearic acid, oleic acid, behenic acid, montanic acid, and derivatives thereof, according to any one of claims 2 to 4. The described coated zinc oxide particles. 6. The metal soap is at least one selected from the group consisting of zinc stearate, magnesium stearate, and calcium stearate.
The coated zinc oxide particles according to. 7. The coated zinc oxide particles according to any one of claims 2 to 6, wherein the zinc oxide particles are particles having a siloxane bond on the surface. 8. A thermoplastic resin composition comprising the coated zinc oxide particles according to any one of claims 2 to 7. 9. The thermoplastic resin composition according to claim 8, which is a compound or a masterbatch. 10. The thermoplastic resin composition according to claim 8, wherein the concentration of zinc oxide particles in the thermoplastic resin composition is in the range of 0.01 to 80% by mass based on the total mass of the composition. 11. A molded product obtained by molding the thermoplastic resin composition according to any one of claims 8 to 10. 12. The molded product according to claim 11, wherein the molded product is at least one selected from the group consisting of fibers, films, and plastics. 13. A method for producing a thermoplastic resin composition according to any one of claims 8 to 10, characterized in that the coated zinc oxide particles according to any one of claims 2 to 7 are used. . 14. A method for producing a molded article according to claim 11 or 12, wherein the thermoplastic resin composition according to any one of claims 8 to 10 is used.