JPH06107798A - Core-shell type polymer bound through chemical bond - Google Patents

Abstract

PURPOSE:To provide the subject polymer where the core polymer represents microsphere, having a diameter within a specified range, excellent in homogeneous dispersibility and compatibility, useful for coatings, adhesives, etc. CONSTITUTION:The objective polymer characterized in that (1) the core polymer represents microsphere; (2) 5-2000 pts.wt. of the shell polymer is contained based on 100 pts.wt. of the core polymer; (3) the diameter falls between 10 and 5000 (pref. 20 and 1000)nm; and (4) the surface of the core polymer is bound to a different kind of virtually straight chain polymer as the shell polymer through chemical bond via amino, imino, pyridyl, amidino, hydroxyl, carboxyl or mercapto group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core-shell type polymer having different kinds of polymers immobilized on the surface of polymer microspheres serving as cores by chemical bonds. The core-shell type polymer is useful as a raw material for paints, paper processing, adhesives, mosaic charge films, separating fillers, catalysts, copying toners and the like.

[0002]

2. Description of the Related Art Conventionally, as a method for modifying the surface of polymer microspheres, seed particles (core microspheres) are first prepared in the first stage, and then a polymerizable monomer of interest is added on the core surface. The method of polymerizing is general, and various studies have been made.

[0003]

In the conventional core-shell type polymer formed by simply combining polymers, the second-stage polymer is not always fixed on the core surface, or the core-shell component is reversed, and May have a dumbbell shape in which the core-shell is separated. The causes of these phenomena are phenomena that can occur mainly when the cohesive energy of the shell part is larger than the core part,
This is the case where the second stage reaction, that is, the presence of the monomer or the presence of a solvent or the like having an affinity for the core, causes the monomer to move between the core and the shell and the second stage polymer not to exist on the core surface. Further, the essential problem is that the core-shell type polymer is formed only between the polymers which are incompatible with the conventional phase separation structure.

Specifically, it is known that a polymer having a high ratio serves as a continuous phase (sea) and a polymer having a low ratio serves as a discontinuous phase (islands), and has a lamellar structure near the same ratio. Conversely, the same composition cannot change the sea-island structure. Therefore, the object of the present invention is to solve the above-mentioned problems, to make the continuous phase (sea) a linear polymer chain, and to make the discontinuous phase (island) a polymer microsphere, and adjust the ratio of the polymers arbitrarily. It is to provide a core-shell type polymer having unprecedented properties, which realizes a new concept that can be realized and enables even when the number of islands in the sea-island structure is larger than that of the sea.

[0005]

The above object can be achieved by the present invention described below. That is, in the present invention, the core polymer has a microsphere shape and a diameter of 10 to 5,0.
It is in the range of 00 nm, and is a core-shell type polymer characterized in that a heterogeneous substantially linear polymer is linked to the surface of the core by a chemical bond.

[0006]

After the core microspheres are prepared, the desired linear polymer chain is chemically bonded to the surface of the core, so that the surface of the microspheres can be reliably modified with the shell polymer. As a result, the surface of the core polymer can be modified in various ways, and as a result, the uniform dispersibility or compatibility of the core polymer microspheres in various media can be arbitrarily adjusted within a very wide range. , The core polymer and the shell polymer can be advantageously brought out.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. In the core-shell type polymer of the present invention, the core microsphere has a diameter in the range of 10 to 5,000 nm, preferably 20 to 1,0.
The range is 00 nm, and the method for producing these cores is not particularly limited, but a typical method is a radical polymerization reaction, and polymerization may be performed in either an aqueous system or a non-aqueous system.
The dispersant used during the polymerization is not particularly limited, and may be a surfactant, an amphipathic monomer (soap-free) or the like.

Typical monomers for preparing the core polymer include 4-vinylpyridine, 2-vinylpyridine, styrene, α-methylstyrene, chloromethylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate and butyl. Examples thereof include (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, hydroxy (meth) acrylate, vinyl acetate and ethylene, and these monomers are homopolymerized or copolymerized to form a polymer core. Although the core polymer varies depending on the post-treatment, the cross-linking agent may be introduced in a proportion of 0 to 20 parts by weight, preferably 15 parts by weight, relative to 100 parts by weight of the core, so that the core polymer can be a cross-linked polymer.
Examples of the cross-linking agent used in this case include divinylbenzene and pentaerythritol poly (meth) acrylate.

The shell polymer to be bound to the surface of the core polymer microsphere is preferably linear and has an appropriate functional group capable of binding to the functional group of the core polymer at one end. Examples of these functional groups include an amino group, an imino group, an imidino group, a hydroxyl group, a carboxyl group, and an epoxy group.As a method for introducing these functional groups into a polymer, an initiator segment by radical polymerization is used. Examples of the introduction method include introduction into an ionic polymerization active terminal or use of a chain transfer agent. Particularly in the case of radical polymerization, a degradable chain transfer agent, for example, an allyl type such as a malonic acid derivative is used. A polymer having a functional group is preferably obtained.

The monomer constituting the shell polymer is different from the monomer component constituting the core. Examples of the initiator that produces a polymer having a functional group used for binding the formed shell polymer to the core polymer include azo-based and peroxide-based initiators, and examples of the azo-based initiator include 2 , 2'-azobis (2
-Methylpropinoamidine) dihydrochloride,
2,2'-azobis [2-methyl-N- (2propenylpropioamidine)] dihydrochloride, and other commercial products of Wako Pure Chemical Industries, Ltd., for introducing an amide group, VA
-558, VA-041, VA-04 for cyclic amide
4, VA-054, VA-058, VA-059, VA
-060, VA-061, VA-08 for hydroxyl group introduction
6, VA-082, VA-080, VF-077, and V-501 for introducing a carboxylic acid group.

Hydrogen peroxide is a typical peroxide type polymerization initiator. Examples of the method of introducing a functional group with a chain transfer agent include thiodiglycol, thiodiglycolic acid, thiopropionic acid, and thiomalic acid. The amount of the shell polymer used is 5 to 2,000 parts by weight, preferably 10 to 1.0, based on 100 parts by weight of the core polymer component.
The range is 00. The bond between the core polymer and the shell polymer is a functional group of both, for example, an amino group, an imino group,
It can be carried out by combining chemical reactions such as quaternization of amidino group, etc., esterification with hydroxyl group and carboxyl group, carboamidation, etherification, etc., but preferably quaternization reaction of amino group etc. is used.

The core-shell type polymer of the present invention synthesized in this manner has relatively good performance separation between the core part and the shell part, and the properties of the core part / shell part can be expressed separately. . For example, a kind of phase-separation property such as hydrophilic / hydrophobic and a combination of different ions can be given, and the conventional core-shell type polymer has a phase-separation structure determined by the mixing ratio of the polymers. In the present invention, it can be optionally prepared.

[0013]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. In addition, unless otherwise specified, "parts" and "%" in the text are based on weight. Reference Example A. Preparation of 4-vinylpyridine microgel 10 parts 4-vinylpyridine, 1 part divinylbenzene, 0.2 parts 2,2'-azobis (2-methyl-2-)
Methylpropinoamidine) dihydrochloride and 5
00 parts of water was placed in a 1 liter flask and polymerized at 70 ° C. for 7 hours in a nitrogen atmosphere. The obtained polymerization solution is in an emulsified state and may be purified by dialysis or by pressure filtration and washing with water. The dried product can be redispersed in water or methanol. The particle size of the resulting polymer spheres is about 150 nm dry, 200 nm in water, and about 500 nm in methanol.

B. Preparation of 4-Vinylpyridine Microgel The polymer microgel synthesized with the crosslinking agent set to 0 in the preparation of A above is dispersed in water, but is dissolved in methanol. C. Preparation of styrenic microgel 10 parts styrene, 1 part 2-vinylpyridine, 0.5
Parts of divinylbenzene and 0.1 part of 2,2'-azobis (2-methyl-2-methylpropinoamidine) and 5
It is prepared by placing 00 parts of water in a flask and polymerizing at 60 ° C. in the same manner as in A.

D. Preparation of linear sodium polysulfonate 12 parts sodium styrenesulfonate, 4 parts acrylamide, 0.5 parts 2,2'-azobis (2-methyl-
2-methylpropinoamidine) dihydrochloride,
0.8 parts of diallyl malonic acid, 1 part of crotonaldehyde and 100 parts of water were placed in a flask and placed under a nitrogen atmosphere.
After reacting at 0 ° C. for 10 hours, the polymer is purified by an acetone-water reprecipitation method and then dried at room temperature. The obtained polymer has a molecular weight of about 44,000 (GPC) and is a polymer having an amidino group at one end. E. Preparation of linear polymethylmethacrylate 10 parts methyl methacrylate, 0.2 parts 2,2'-azobis (2-methylpropinoamidine) dihydrochloride, 0.4 parts diallyl malonic acid, 500 parts Water and 0.1 part sodium lauryl sulfonate at 50 ° C for 10
After the reaction for a certain period of time, pressure filtration, washing, and vacuum drying are performed to obtain the target polymer.

Example 1 1 part of the linear sodium polysulfonate of Reference Example (D) was added to 10 parts.
1 part of water, 0.5 part of sodium bicarbonate is dissolved therein, and the mixture is stirred for 5 hours. To this, 1 part of epibromhydrin is added and reacted at 45 ° C. for 10 hours. The reaction solution is purified by dialysis. The bromine in the reaction product was ionized with an alkali and quantified, and the molecular weight was about 40,000 when one was attached to one end of the polymer,
It almost agreed with the analysis result by GPC. This polymer aqueous solution was adjusted to a solid content of 5%, 40 parts of which were taken, and
Mix with the 10% poly-4-vinylpyridine methanol solution shown in Part (A) of Reference Example. After reacting for 24 hours at room temperature, it was filtered, washed with water and dried under reduced pressure. From the quantification of the aldehyde and the observation by the transmission electron microscope (TEM), the linear polymer (D) is present only on the pyridine surface and is present in a ratio of 1 to 10 pyridine units. In some cases, the nitrogen atom can be completely quaternized with methyl iodide or the like. The core-shell type polymer of the present invention thus obtained is useful as a mosaic charge film and a charge control agent.

Example 2 The polymer of Example 1 was replaced with the polymer of Reference Example (B), dispersed in water (solid content 2%), and the core of the present invention was prepared by the same ratio and operation as in Example 1. A shell type polymer was obtained. The core portion of the core-shell type polymer obtained here is destroyed by the vapor of methanol to increase the film-forming ability, and can be crosslinked with diiodobutane or the like, and in some cases, it is completely quaternized with methyl iodide or the like. It can be graded. The use of this core-shell type polymer is the same as in Example 1.

Example 3 The polymer shown in Reference Example (C) is dispersed in methanol (solid content 3%). An aqueous solution of the polymer (D) treated with epibromhydrin (solid content 10%) was added to a solid content ratio of 1 /
The mixture is mixed with the above dispersion at 0.5, and after the reaction, pressure filtration, washing with water and drying under reduced pressure are carried out. This core-shell polymer can be redispersed in water. Coating the surface of a plastic or woven fabric with this core-shell type polymer dispersion is effective as an antistatic agent.

Example 4 The polymer shown in Reference Example (E) was dissolved in a mixed solvent of methanol / toluene = 1/2, treated with epibromhydrin, and precipitated and purified with a large amount of methanol. After that, it is dissolved in a mixed solvent of methanol / toluene = 1/2. The polymer (A) (methanol solid content = 10%) is mixed with this at a solid content ratio (A / E) = 2/1, and a reaction treatment is carried out. This core-shell type polymer can be dispersed in acetone or the like, and is effective as an antistatic agent when coated on the surface of plastic.

[0020]

[Effects] According to the present invention as described above, since the target linear polymer chain is chemically bonded to the surface of the core after the core microsphere is prepared, the surface of the microsphere is surely modified with the shell polymer. You can do it. As a result, the surface of the core polymer can be modified in various ways, and as a result, the uniform dispersibility or compatibility of the core polymer microspheres in various media can be arbitrarily adjusted within a very wide range. , The core polymer and the shell polymer can be advantageously brought out.

Claims (5)

[Claims] 1. The core polymer has a microsphere shape and has a diameter in the range of 10 to 5,000 nm.
A core-shell type polymer, wherein different types of substantially linear polymers are linked to the surface of the core by chemical bonds. 2. The core according to claim 1, wherein the core-shell type polymer is chemically bonded through an amino group, an imino group, a pyridyl group, an amidino group, a hydroxyl group, a carboxylic acid group or a mercapto group. Shell type polymer. 3. The core-shell type polymer according to claim 1, wherein the shell polymer is in the range of 5 to 2,000 parts by weight with respect to 100 parts by weight of the core polymer. 4. The core-shell type polymer according to claim 1, wherein the shell polymer is substantially one-end functional. 5. The core-shell type polymer according to claim 1, wherein the core polymer is crosslinked or non-crosslinked.