JPH05306315A - Mono-dispersed polymer particle - Google Patents

Abstract

PURPOSE:To obtain a particle free from isolated dispersion stabilizer, having small particle diameter and mono-dispersed particle size distribution and useful as a filler for paint, toner for electrophotography, etc., by carrying out the dispersion copolymerization of a specific macromonomer and a styrene derivative. CONSTITUTION:This particle having particle diameter of several mum can be produced by the dispersion copolymerization of (A) a poly(2-oxazoline) macromonomer of formula I (R is 1-4C alkyl; X is OH; (n) is 6-50) and (B) a styrene derivative (e.g. styrene or alpha-methylstyrene). The component A is preferably produced by (co)polymerizing a 2-alkyl-2-oxazoline of formula III (preferably 2-butyl-2-oxazoline, etc.) using a styryl compound of formula II (Z is electrophilic group such as Br or I) as a radical initiator. The dispersion copolymerization of the components A and B is preferably carried out in the presence of a peroxide-type initiator such as benzoyl peroxide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a filler for paints, a slipperiness imparting agent for tapes and films, an electrophotographic toner, a column filler, particles for immunodiagnosis, a gap adjusting agent and particle size for liquid crystal display panels. The present invention relates to spherical polymer particles useful as standard particles for measurement.

[0002]

2. Description of the Related Art Conventionally, a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method and the like are known as methods for producing spherical polymer particles. These production methods are characterized by the particle size and particle size distribution of the obtained polymer particles, the molecular weight of the polymer, and the like. For example, in the suspension polymerization method, several μm to several hundred μm
Particles having a large particle size can be produced, but only particles having a polydisperse particle size distribution can be obtained. By the emulsion polymerization method, particles having a monodisperse particle size distribution can be produced, but it is difficult to obtain particles having a particle size of 1 μm or more.

The dispersion polymerization method is a polar solvent or a polar solvent /
In this method, a high molecular weight hydrophilic polymer such as polyacrylic acid and hydroxypropyl cellulose is used as a dispersion stabilizer in an aqueous medium such as a water-mixed solvent. In the dispersion polymerization method, the particle size is several μm (for example, 1 to 5 μm).
In m), particles having a monodisperse particle size distribution can be produced.

However, since the hydrophilic polymer is used as the dispersion stabilizer in the polymerization system, the resulting polymer particles contain the hydrophilic polymer. Therefore, the obtained polymer particles become hydrophilic, which causes a problem of lowering water resistance of the final product. In order to prevent such problems, it is necessary to remove the dispersion stabilizer from the particle system. However, in order to wash and remove the dispersion stabilizer, a complicated operation such as an ultrafiltration method is required, which lowers the productivity and raises the manufacturing cost. Furthermore, it is virtually impossible to remove the dispersion stabilizer incorporated inside the polymer particles.

Therefore, in order to obtain a final product having excellent water resistance at a low cost, there is a demand for polymer particles containing no hydrophilic component such as conventional dispersion stabilizers.

In order to solve such a problem, the present inventors have already reported on the preparation of monodisperse polymer particles by dispersion copolymerization of methyl methacrylate and poly (2-oxazoline) macromonomer (S. Kobayashi). (Kobayash
i), H. Uyama, JH Choi, and Y. Matsumoto, Proc. Japan Acad., Volume 67B, Volume 1.
40 pages (1991)). However, there are problems in non-deformability of particles and solvent resistance.

[0007]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and an object thereof is to obtain a particle size of several μm and a monodisperse particle size, which does not contain a free dispersion stabilizer. To provide polymer particles having a distribution.

[0008]

The present invention is based on the formula

[0009]

[Chemical 2]

[In the formula, R is an alkyl group having 1 to 4 carbon atoms, X is OH, and n is an integer of 6 to 50. ] To provide a poly (2-oxazoline) macromonomer having a structure shown by, and a styrene derivative, monodisperse polymer particles having a particle diameter of several μm obtained by dispersion copolymerization, thereby providing a conventional The problem is solved.

The poly (2-oxazoline) macromonomer used in the present invention has the formula

[0012]

[Chemical 3]

Wherein Z is an electrophilic group such as Br, I and RSO ₃ . ] The styryl compound having a structure shown in

[0014]

[Chemical 4]

[In the formula, R represents an alkyl group having 1 to 4 carbon atoms. ] At least one 2-alkyl- having the structure shown in
It can be prepared by polymerizing or copolymerizing 2-oxazoline. This polymerization is described by DA Tomalia et al., US Pat. No. 4,261,925 (1981); Proceedings of Japan-US Polymer Symposium, S. Kobayashi (K).
obayashi), p. 24, 1985; and S. Kobayashi, Pro.
g. Polym. Sci., Vol. 15, p. 751, 1990, preferably.

The alkyl substituent of 2-alkyl-2-oxazoline suitable for preparing the poly (2-oxazoline) macromonomer used in the present invention preferably has 1 to 4 carbon atoms. When the number of alkyl substituents exceeds 4, it becomes ... Specific examples of 2-alkyl-2-oxazoline that can be preferably used in the present invention include 2-butyl-2-oxazoline and 2-methyl-
2-oxazoline, 2-ethyl-2-oxazoline, 2-isopropyl-2-oxazoline and the like can be mentioned. The mixing ratio of 2-alkyl-2-oxazoline in the copolymerization step is not particularly limited.

The poly (2-oxazoline) macromonomer used in the present invention preferably has a number average molecular weight in the range of 500 to 5,000, particularly in the range of 2,000 to 5,000. When the number average molecular weight is less than 500, the dispersibility becomes insufficient and monodisperse polymer particles cannot be obtained. If the number average molecular weight exceeds 5,000, the distribution tends to be broad. Poly (2-oxazoline)
The molecular weight of the macromonomer is adjusted by increasing or decreasing the amount of the styryl compound initiator with respect to the amount of each oxazoline monomer used as a raw material. Generally, by using a styryl compound initiator in an amount of 2 to 25% by weight based on the oxazoline monomer, a poly (2-oxazoline) macromonomer having a number average molecular weight in the range of 500 to 5,000 is obtained.

A styrene derivative is preferably used as a comonomer to be copolymerized with the poly (2-oxazoline) macromonomer. This is because it is easy to obtain a monodisperse particle size. Specifically, styrene, α-methylstyrene, t-butylstyrene, parachlorostyrene, vinylnaphthalene
Examples include, but are not limited to, 2-hydroxyethyl acrylate and combinations thereof.

The polymer particles of the present invention are the above-mentioned poly (2-
It is obtained by dispersion-polymerizing a monomer composition containing at least an oxazoline) macromonomer, a styrene derivative, and a radical polymerization initiator in an aqueous medium.

The mixing ratio of the poly (2-oxazoline) macromonomer and the styrene derivative in the monomer composition is
It is preferably in the range of 0.5 to 10 wt%. If the mixing ratio of the poly (2-oxazoline) macromonomer and the styrene derivative deviates from the above range, monodispersity tends to be lost, which is not preferable.

The polymerization initiator that can be used in this dispersion polymerization is not particularly limited as long as it is a radical polymerization initiator. Azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 4,4'-azobis (4-cyanovaleric acid) ) And 2,2'-azobis (2-methylpropionamidine) -like azo initiators; and peroxides such as benzoyl peroxide, halochlorobenzoyl peroxide, lauroyl peroxide and t-butyl perbenzoate It is particularly preferable to use a system initiator. The polymerization initiator is contained in the monomer composition in an amount of about 0.1 to 5% by weight.

The solvent used in this dispersion polymerization is poly (2-
An aqueous medium is preferred in which the oxazoline) macromonomer and the styrene derivative are soluble, but the copolymer obtained from the monomer is insoluble. Specific examples of such a solvent include a lower alcohol such as methanol, ethanol, isopropanol, and n-butanol, or a mixed solvent of such a lower alcohol and water.

Dispersion polymerization is based on 10 to 60% by weight of the monomer composition.
Is charged into a reactor containing 90 to 40% by weight of an aqueous medium equipped with a stirrer, a cooling pipe, a temperature control device, a thermometer and the like, and usually heated and stirred at about 50 to 90 ° C.
At this time, in order to smoothly carry out the polymerization, it is desirable to replace most of the air in the reactor with an inert gas such as nitrogen gas.

The poly (2-oxazoline) macromonomer used in the present invention has excellent dispersibility. Therefore, the poly (2-oxazoline) macromonomer is dispersed in the aqueous medium together with the styrene derivative so as to have a uniform particle size in the polymerization step. As a result, polymer particles having a particle size of several μm and a monodisperse particle size distribution, which does not contain a free dispersion stabilizer, are obtained.

The particle size of the monomer fine particles dispersed in the copolymerization step depends on the poly (2-oxazoline) used.
It tends to decrease as the concentration of macromonomer increases. Further, the particle size of the monomer fine particles tends to be reduced by reducing the poly (N-valeroylethyleneimine) chain length which is a hydrophobic segment of the poly (2-oxazoline) macromonomer. Therefore, the particle size of the polymer particles of the present invention can be easily controlled.

[0026]

EXAMPLES The present invention will be explained in more detail by the following examples, but the present invention is not limited to these.

[0027]

[Production Example 1] 30 mL of acetonitrile, 2-isopropyl-2-oxazoline (11.8 g, 104 mmol) chloromethylstyrene (0.492) in a 100 mL glass container under a dry argon atmosphere.
g, 3.22 mmol) and sodium iodide (0.495 g, 3.30 mmo
l) was charged and stirred at room temperature for 2 hours. Then at 80 ° C
Heated for 48 hours. After returning to room temperature, 3.30 mL (3.30 mmol) of 1N sodium hydroxide methanol solution was added and stirred for 1 hour. Then the solvent was evaporated off and the residue was extracted with chloroform. The extract was concentrated to obtain 11.9 g (yield: 98%) of a pale yellow powdery polymer.

The reaction route is shown in the following formula.

[0029]

[Chemical 5]

[In the formula, R represents an isopropyl group. ]

GPC: Mw = 4200 Mw / Mn = 1.20 ¹ H-NMR (CDCl ₃ , δ value) 1.1 (d, CH ₃ C), 2.2-2.5 (m, CHC = O), 2.9-3.9 (br, CH
₂ N), 5.3, 5.7, 6.7 (m, CH ₂ = CH), 6.9-7.6 (m, Ar) IR (KBr) 3400 cm ^-1 (ν OH), 1630 cm ^-1 (ν C = O) The properties of the macromonomers are shown in Table 1 below.

[0032]

Production Example 2 Except that methyl-2-oxazoline was used in place of isopropyl-2-oxazoline and the weight average molecular weight was adjusted to 3900, the same procedure as in Production Example 1 was repeated.
A macromonomer was obtained. The properties of the obtained macromonomer are shown in Table 1.

[0033]

[Production Example 3] Ethyl-2-oxazoline was used in place of isopropyl-2-oxazoline, and the weight average molecular weight was 35.
A macromonomer was obtained in the same manner as in Production Example 1 except that the amount was adjusted to 00. The properties of the obtained macromonomer are shown in Table 1.

[0034]

[Production Example 4] A macromonomer was obtained in the same manner as in Production Example 3 except that the molecular weight was adjusted to 1400. The properties of the obtained macromonomer are shown in Table 1.

[0035]

[Table 1]

[0036]

Example 1 Poly (2-methyl-2-oxazoline) macromonomer (0.015 g) obtained in Production Example 2, styrene (14.85 g), V-65 in a 30 mL glass container under a dry argon atmosphere.
(2,2 '-(2,4-dimethylvaleronitrile)) (0.03g), water (1.3
5 g) and ethanol (12.15 g) were charged, and the mixture was shaken at 56 ° C for 24 hours (shaking rate-150 times per minute). After the aggregate was filtered off with a wire net, a white powder polymer was isolated by centrifugation (20,000 rpm, 10 minutes). Yield 1.2g (Yield 80
%). Molecular weight (GPC) Mn = 35,000, Mw / Mn = 3.55 Particle size (SEM) Dn (micron) = 2.11, Dw / Dn =
1.01 Surface analysis (ESCA) [poly (2-oxazoline)] /
[Polystyrene] = 0.22 (preparation ratio 0.012) The characteristics of the obtained fine particles are shown in Table 2 below.

[0037]

Example 2 Poly (2-ethyl-2-oxazoline) macromonomer (0.030 g) obtained in Production Example 3, styrene (14.70 g), V- in a 30 mL glass container under a dry argon atmosphere.
65 (2,2 '-(2,4-dimethylvaleronitrile)) (0.03
g), water (4.05 g) and ethanol (9.45 g) were charged, and the temperature was 56 ° C.
It was shaken for 24 hours (shaking speed-150 times per minute). After filtering the aggregate with a wire mesh, centrifuge (20,000 rpm,
White powder polymer was isolated according to (10 min). yield
1.35 g (yield 90%). Molecular weight (GPC) Mn = 84,000, Mw / Mn = 4.11 Particle size (SEM) Dn (micron) = 1.29, Dw / Dn =
1.02 The characteristics of the obtained fine particles are shown in Table 2 below.

[0038]

Example 3 The poly (2-isopropyl-2-oxazoline) macromonomer (0.015 g) obtained in Production Example 1 and styrene (14.85%) were placed in a 30 mL glass container under a dry argon atmosphere.
g), V-65 (2,2 ′-(2,4-dimethylvaleronitrile)) (0.03 g), water (1.35 g) and ethanol (12.15 g) were charged, and the mixture was shaken at 56 ° C. for 24 hours ( Shaking rate-15 per minute
0 times). After the aggregate was filtered off with a wire net, a white powder polymer was isolated by centrifugation (20,000 rpm, 10 minutes). Yield 1.05 g (70% yield). Molecular weight (GPC) Mn = 43,000, Mw / Mn = 3.89 Particle size (SEM) Dn (micron) = 2.16, Dw / Dn =
1.02 The characteristics of the obtained fine particles are shown in Table 2 below.

[0039]

Example 4 Poly (2-ethyl-2) obtained in Production Example 4
Fine particles were obtained in the same manner as in Example 2 except that the -oxazoline) macromonomer was used in the formulation shown in Table 2 below. The characteristics of the obtained fine particles are shown in Table 2 below.

[0040]

Example 5 Poly (2-ethyl-2) obtained in Production Example 2
Fine particles were obtained in the same manner as in Example 1 except that the -oxazoline) macromonomer was used in the formulation shown in Table 2 below. The characteristics of the obtained fine particles are shown in Table 2 below.

[0041]

[Table 2]

[0042]

EFFECTS OF THE INVENTION A few μm containing no free dispersion stabilizer
Polymer particles having a particle size of 100 μm and a monodisperse particle size distribution were provided.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keizo Ishii 19-17 Ikedanaka-cho, Neyagawa-shi, Osaka Japan Paint Co., Ltd.

Claims (2)

[Claims] 1. The formula: [In the formula, R is an alkyl group having 1 to 4 carbon atoms, X is OH, and n is an integer of 6 to 50. ] A monodisperse polymer particle having a particle diameter of several μm, which is obtained by dispersion copolymerization of a poly (2-oxazoline) macromonomer having a structure shown in [4] and a styrene derivative. 2. The polymer particles according to claim 1, which have a particle size of 1 to 5 μm.