HOLLOW POLYMER PARTICLES AND METHOD FOR MANUFACTURING SAME

Abstract

Hollow polymer particles comprising a polymer containing a vinylic monomer unit and a phosphate ester monomer unit, the hollow polymer particles having a volume average particle diameter of 0.5 to 1000 μm.

Claims

1. Hollow polymer particles comprising a polymer containing a vinylic monomer unit and a phosphate ester monomer unit, the hollow polymer particles having a volume average particle diameter of 0.5 to 1000 μm.

2. The hollow polymer particles according to claim 1, wherein the phosphate ester monomer unit has an ethylenically unsaturated group.

3. The hollow polymer particles according to claim 1, wherein the phosphate ester monomer unit is represented by the following formula (1): ##STR00005## wherein R.sub.1 is a (meth)acrylic group or an allyl group, R.sub.2 is a linear or branched alkylene group, m is an integer of 1 to 30, n is 0 or 1, v is an integer of 1 to 10, and x is 1 or 2.

4. Hollow polymer particles comprising a polymer containing a vinylic monomer unit, the hollow polymer particles having a phosphorus element content of 2 to 200 mg/kg and an alkaline earth metal element content of 1 to 100 mg/kg, wherein the phosphorus element content is larger than the alkaline earth metal element content, and the hollow polymer particles having a volume average particle diameter of 0.5 to 1000 μm.

5. The hollow polymer particles according to claim 1, which have a specific surface area of 1 to 30 m.sup.2/g and a bulk specific gravity of 0.1 to 0.4 g/cm.sup.3.

6. The hollow polymer particles according to claim 1, wherein the particles each have a porous structure inside thereof.

7. The hollow polymer particles according to claim 1, wherein the particles each have only one pore inside thereof.

8. A resin composition comprising the hollow polymer particles according to claim 1.

9. A coating composition comprising the hollow polymer particles according to claim 1.

10. A cosmetic comprising the hollow polymer particles according to claim 1.

11. A light diffusion film comprising the hollow polymer particles according to claim 1.

12. A method for producing hollow polymer particles, the method comprising subjecting a monomer mixture containing 0.01 to 1 part by mass of a phosphate ester monomer unit based on 100 parts by mass of a vinylic monomer unit to suspension polymerization in the presence of a non-polymerizable organic compound and a dispersant.

13. The method for producing hollow polymer particles according to claim 12, wherein the dispersant is a phosphate of an alkaline earth metal.

Description

EXAMPLES

[0087] The embodiments of the present invention are described in more detail below based on Examples; however, the present invention is not limited thereto.

Method for Measuring Volume Average Particle Diameter of Hollow Polymer Particles

[0088] The hollow polymer particles were measured by the Coulter method as described below.

[0089] The volume average particle diameter of the hollow polymer particles is measured with a Coulter Multisizer™ 3 (analyser produced by Beckman. Coulter). The measurement is carried out using an aperture calibrated according to the Multisizer™ 3 user's manual, published by Beckman Coulter.

[0090] The aperture used for measurement is suitably selected depending on the size of the hollow polymer particles to be measured. The current (aperture current) and gain are suitably set depending on the size of the selected aperture, her example, when an aperture having a size of 50 μm is selected, the current (aperture current) is set to be −800, and the gain is set to be 4. The measurement sample used is a dispersion obtained by dispersion 0.1 g of hollow polymer particles in 10 ml of a 0.1 wt % nonionic surfactant aqueous solution using a touch mixer (Touch Mixer MT-31, produced by Yamato Scientific Co., Ltd.) and an ultrasonic cleaner (Ultrasonic Cleaner VS-150, produced by Velvo-Clear Co.). During measurement, gentle stirring is performed to an extent in which bubbles are not formed in the beaker. The measurement is ended when the measurement of 100000 hollow polymer particles is completed. The volume average particle diameter of the hollow polymer particles is the arithmetic mean in the particle site distribution on a volume basis of 100000 particles.

Specific Surface Area

[0091] The specific surface area of the hollow polymer particles was measured according to the BET method (nitrogen adsorption method) described in ISO 9277, 1st edition, JIS Z 8830:2001. For the target hollow polymer particles, the BET nitrogen adsorption isotherm was measured using an automated surface area end porosity analyser (TriStar XT, produced by Shimadzu Corporation). The specific surface area was calculated from the amount of nitrogen adsorbed using the BET multipoint method.

[0092] After pretreatment by heating gas purging, nitrogen, was used as an adsorbate, and the measurement was carried out using the constant volume method under conditions in which the cross-sectional area of the adsorbate was 0.162 nm.sup.2. Specifically, the pretreatment was carried out by performing a nitrogen purge for 20 minutes while heating a container containing resin particles at 65° C., allowing the container to cool at room temperature, and then performing vacuum degassing until the pressure inside the container was 0.05 mmHg or less while heating the container at 65° C.

Bulk Specific Gravity

[0093] The bulk specific gravity of the hollow polymer particles was measured according to JIS K5101-12-1 (Test methods for pigments—Part 12: Apparent density or apparent specific volume—Section 1: Loose packing method).

Example 1

[0094] 105 parts by mass of methyl methacrylate, 45 parts by mass of trimethylolpropane trimethacrylate, 0.3 parts by mass KAYMER™ PM-21. (produced by Nippon Kayaku Co., Ltd.) as a polymerizable monomer having an acidic phosphate ester group, 0.45 parts by mass of AVN (produced by Japan Finechem Company, Inc.) as a polymerisation initiator, and 75 parts by mass of ethyl acetate and 75 parts by mass of cyclohexane as non-polymerizable organic compounds were mixed to prepare an oil phase. Further, 900 parts by mass of deionised water as an aqueous medium, and 23 parts by mass of magnesium pyrophosphate produced fey the metathesis method as a dispersant were mixed to prepare an aqueous phase.

[0095] Next, the oil phase was dispersed in the aqueous phase using a TK homomixer (produced by RRIMIX Corporation) at 8000 rpm for 5 minutes to obtain a dispersion (about 8 μm). Then, the dispersion was placed in a polymerizes equipped with a stirrer and a thermometer, the internal temperature of the polymerizer was raised to 55%, and the suspension was continuously stirred for 5 hours. Thereafter, the infernal temperature of the polymerizer was raised to 70° C. (secondary temperature rise), and the suspension was stirred at 70% for 2 hours. Thus, the suspension polymerization reaction was completed.

[0096] After cooling the suspension, the dispersant (magnesium pyrophosphate) contained in the suspension was decomposed with hydrochloric acid. Then, the suspension was dehydrated by filtration to separate solids, and the solids were washed with sufficient water. Thereafter, the non-polymerizable organic compounds were removed by vacuum-drying at 70% for 24 hours, thereby obtaining spherical polymer particles. The average particle diameter of the obtained polymer particles was 8.0 μm. According to SEM observation, the obtained polymer particles had a porous shape inside. The bulk specific gravity was 0.33 g/ml. Further, the specific surface area of the obtained particles measured before and after treatment with a jet mill at a pressure of 0.4 MPa was 8.2 m.sup.2/g and 23.2 m.sup.2/g, respectively.

Example 2

[0097] Polymer particles were obtained in the same manner as in Example 1, except that 54 parts by mass of styrene, 36 parts by mass of ethylene glycol dimethacrylate, 105 parts by mass of cyclohexane, and 105 parts by mass of ethyl acetate were used.

Example is 3

[0098] Polymer particles were obtained in the same manner as in Example 1, except that 135 parts by mass or methyl methacrylate and 15 parts by mass of trimethylolpropane trimethacrylate were used.

Example 4

[0099] Polymer particles were obtained in the same manner as in Example 1, except that 105 parts by mass of isobutyl methacrylate and 45 parts by mass of ethylene glycol dimethacrylate were used.

Example 5

[0100] Polymer particles were obtained in the same manner as in Example 1, except that 105 parts by mass of styrene, 45 parts by mass of trimethylolpropane trimethacrylate, and 0.8 parts by mass of Adekaria Soap PP-70 (produced by ADERA Corporation) as a polymerizable monomer having an acidic phosphate ester group were used.

Example 6

[0101] Polymer particles were obtained in the same manner as in Example 1, except that 150 parts by mass of cyclohexane was used as a non-polymerizable organic compound. The obtained particles had only one pore inside.

Example 7

[0102] When the prepared oil phase was dispersed in the aqueous phase in Example 1, the rotation speed of the TK homomixer was changed to 2500 rpm, and a dispersion (about 35 μm) was obtained. The subsequent polymerisation step and ether steps were performed in the same manner as in Example 1, thereby obtaining polymer particles.

Example 8

[0103] 65 parts by mass of methyl methacrylate, 05 parts by mass of ethylene glycol dimethacrylate, 0-3 parts by mass of KAYAMER™ PM-21 as a polymerisable monomer having an acidic, phosphate ester group, 0.75 parts by mass of AVN as a polymerisation initiator, and 75 parts by mass of ethyl acetate and 75 parts by mass of cyclohexane as non-polymerizable organic compounds were mixed to prepare an oil phase, further, 900 parts by mass of deionised water as an aqueous medium, and 30 parts by mass or tricalcium phosphate as a dispersant were mixed to prepare an aqueous phase.

[0104] Polymer particles were obtained in the same manner as in Example 1, except for the above. The average particle diameter of the obtained polymer particles was 3-0 μm. According to SEM observation, the obtained polymer particles had a porous shape inside. The fault specific gravity was 0.32 g/ml. Further, the specific surface area of the obtained particles measured before and after treatment with a jet mill at a pressure of 0.4 MPa was 7.2 m.sup.2/g and 10.2 m.sup.2/g, respectively.

Comparative Example 1

[0105] Polymer particles were obtained in the same manner as in Example 1, except that KAYMER PM-21 was not used as a polymerizable monomer having an acidic phosphate ester group. The obtained particles were porous particles.

Comparative Example 2

[0106] 105 parts by mass of styrene, 15 parts by mass of trimethylolpropane trimethacrylate, 1.5 parts by mass of AVN (produced by Japan Finechem Company, Inc.) as an oil-soluble polymerization initiator, and 150 parts by mass of cyclohexane as a non-polymerizable organic compound were mixed to prepare an oil phase. Further, 500 parts by mass of deionized water as an aqueous medium, 1 part by mass of sodium lauryl sulfate as a surfactant, and 2.3 parts by mass of VA-057 (produced by Wake Pure Chemical Industries, Ltd.) as a water-soluble polymerization initiator were raised to prepare an aqueous phase.

[0107] Hunt, the oil phase was dispersed in the aqueous phase using a TK homomixer (produced by PRIMIX Corporation) at 8000 rpm for 5 minutes to obtain a dispersion (about 8 μm). Then, the dispersion was placed in a polymerizable equipped with a stirrer and a thermometer, the internal temperature of the polymerizer was raised to 60° C., and the suspension was continuously stirred for 5 hours. Thereafter, the internal temperature of the polymerizer was raised to 70° C. (secondary temperature rise), and IQ the suspension was stirred at 70% for 2 hours. Thus, the suspension polymerization reaction was completed.

[0108] After cooling the suspension, the suspension was dehydrated by filtration to separate solids, and the solids were washed with sufficient water. Then, the non-polymerizable organic compound was removed by vacuum-drying at 70% for 24 hours, thereby obtaining polymer particles. The average particle diameter of the obtained polymer particles was 8.0 μm. According to SEM observation, the obtained polymer particles had a porous shape inside.

Mechanical Strength Evaluation Test

[0109] The obtained hollow polymer particles of the Examples and Comparative Examples were passed through a jet mill (Current Jet CJ-10, produced by Nisshin Engineering Inc.) at a pressure of 0.4 MPa with a feeding rate of 5 g/min.

Measurement of Phosphorus Element and Alkaline Earth Metal Element

[0110] The phosphorus element content and the alkaline earth metal element content were measured with a multitype ICP emission spectrometer (ICPE-9000, produced by Shimadzu Corporation). 1.0 g of hollow polymer particles was accurately weighed and heated at 450° C. for 3 hours with an electric furnace (STR-15K muffle furnace, produced by Isuzu) to be ashed. The ashed hollow polymer particles were dissolved in 2 ml of concentrated hydrochloric acid, and distilled water was added to take a total volume of 50 ml, thereby obtaining a measurement sample. Then, the measurement sample was measured with the multitype ICF emission spectrometer under the following measurement conditions to obtain peak intensities at wavelengths of elements (Na, Ca, Mg, Fe, Cr, and P). Subsequently, the concentrations (μg/ml) of the elements (Na, Ca, Mg, Fe, Cr, and P) in the measurement sample were calculated from the obtained peak intensities at the wavelengths of the elements (Na, Ca, Ca, Mg, Fe, Cr, and P) based on a calibration curve for quantification prepared by the method for preparing a calibration curve described below. The concentration Tc (μg/ml) of each element (Na, Ca, Mg, Fe, Cr, and P) and the weight W (g) of the weighed hollow polymer particles were substituted into the following equation to calculate the element content in the hollow polymer particles.

Element content=(Tc(μg/ml)/W(g))×50 (ml)

Measurement Conditions

[0111] Measurement wavelength: Na (589.592 m), Ca (317.933 nm), Mg (285.213 nm), Fe (238.204 ran), Cr (205.552 nm), P (177.499 nm)
Viewing direction: axial direction
Radio frequency output: 1.20 kW
Carrier flow rate: 0.7 L/min
Plasma flow rate: 10.0 L/min
Auxiliary flow rate: 0.6 L/min
Exposure time: 30 seconds

Method for Preparing Calibration Curve

[0112] A standard solution for a calibration curve (XSTC-13 (general-purpose mined standard, solution, mixture of 31 elements (base: 5% HNO.sub.3) each in an amount of about 10 mg/l) produced by SPEW, USA) was serially diluted with distilled water to prepare standard solutions at concentrations of 0 ppm (blank), 0.2 ppm, 1 ppm, 2.5 ppm, and 5 ppm. The standard solution at each concentration was measured with the multitype ICP emission spectrometer under the measurement conditions described above to obtain peak intensities at wavelengths of elements (Na, Ca, Mg, Fe, and Cr). The concentrations and peak intensities of the elements (Na, Ca, Mg, Fe, and Cr) were plotted to determine an approximate line (straight line or quadratic curve) by the least-squares method, and the approximate line was used as a calibration curve for quantification.

[0113] As shown in the following Table 1, the hollow polymer particles of the Comparative Examples were collapsed due to the jet mill treatment to expose the internal porous structure, and the specific surface area significantly increased compared to before the jet mill treatment. In contrast, it was confirmed that, the increase in the specific surface area of the hollow polymer particles of the Examples after the jet mill treatment tended to be suppressed.

TABLE-US-00001 TABLE 1 Com- Com- parative parative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 1 Example 2 Polymerizable MMA 105 135 105 135 85 105 monomer Styrene 54 105 105 IBMA 105 85 EGDMA 36 45 TMPTA 45 15 45 45 45 45 DVB 45 PM-21 0.3 0.3 0.3 0.3 0.3 0.3 0.3 — — PP-70 0.6 Polymerization AVN 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 1.5 initator VA-057 2. Non- Ethyl 75 105 75 75 75 75 75 75 polymerizable acetate organic Cyclo- 75 105 75 75 75 150 75 75 75 150 compound hexane Dispersant Magne- Magne- Magne- Magne- Magne- Magne- Magne- Tracium Magne- Sodium sium sium sium sium sium sium sium phosphate sium lauryl pyro- pyro- pyro- pyro- pyro- pyro- pyro- pyro- sulfide phosphate phosphate phosphate phosphate phosphate phosphate phosphate phosphate Particle μm 7.8 7.5 8.2 7.6 6.5 8.4 35 8.0 8.1 8.1 diameter Particle Porous Porous Porous Porous Porous Single Porous Porous Porous Porous structure inside inside inside inside inside inside inside inside Phosphorous mg/kg 50 48 55 45 30 45 25 35 Not Not element detected detected content Alkaline earth mg/kg 23 24 21 22 7 24 5 15 20 Not metal element detected content Specific m 6.2 3.5 3.5 5.4 1.9 1.1 10.3 7.2 65 1.9 surface area Bulk specific g/m 0.33 0.3 0.38 0.33 0.29 0.3 0.35 0.32 0.37 0. gravity Specific m 23.2 8.5 24 10.3 5.4 1.7 20.5 15.2 91 90 surface area after jet milling MMA: methyl methacrylate EGDMA: ethylene glycol dimethacrylate IBMA: isobutyl methacrylate TMFTA: trimethylcyclopropane trimethacrylate DVB: divinylbenzene AVN: 2,2′-arabis 2,4-dime VA-057: 2,2′-azobis(2-[N-(2- indicates data missing or illegible when filed

Example 3

[0114] 7.5 parts by mass of the hollow polymer particles obtained in Example 2, 30 parts by mass of acrylic resin (product name: Acrydic A811, produced by DIO Corporation), 10 parts by mass of a cross-linking, agent (product: name: VM-D, produced by DIG Corporation), and 50 parts by mass of butyl acetate as a solvent were mined for 3 minutes using a stirring and defoaming device/and defoamed for 1 minute, thereby obtaining a light diffusion resin composition.

[0115] The resulting light diffusion resin composition was applied to a PET film with a thickness of 125 μm using a coating device with a blade with a clearance of 50 pit, followed by drying at 70° C. for 10 minutes, thereby obtaining a light diffusion film A.

Comparative Example 3

[0116] A light diffusion film B was obtained in the same manner as in Example 9, except that, the hollow polymer particles obtained in Comparative Example 2 were used.

Scratch Evaluation Test

[0117] The coated surface of the obtained light diffusion films was reciprocally polished with a cloth 20 times using a friction fastness tester, and the degree of scratches in the light diffusion films after polishing was visually observed. One without line scratches or peeling of the coating film was evaluated as ◯, and one with line scratches and peeling of the coating film was evaluated as x.

Haze and Total Light Transmittance Measurement Test

[0118] The total light transmittance of the light diffusion films was measured according to JIS K7361-1, and the hare was measured according to JIS K7136. Specifically, the total light transmittance and hate of the light diffusion films were measured using a base meter (NDH2000) commercially available from Nippon Denshoku Industries Co., Ltd.

[0119] An shown in the following Table 2, the film of Comparative Example 3 did not give favorable results in the evaluation of scratch resistance. On the other hand, the film of Example 9 gave a good evaluation result of scratch resistance,

TABLE-US-00002 TABLE 2 Total light Haze transmittance Scratch resistance Light diffusion film A 87% 62% ◯ Light diffusion film B 85% 63% X