JPH04258636A - Production of composite polysiloxane/polymer particle - Google Patents

Abstract

PURPOSE:To produce easily and efficiently the title particles which have been difficult to produce because of poor compatibility with an organic polymer in spite of high usefulness. CONSTITUTION:The title particles are obtained by condensing an organosiloxane of the general formula: RnSiO(4-n)/2 (wherein R is a substituted or unsubstituted monovalent hydrocarbon group, and (n) is an integer of 0-3) in the presence of organic polymer particles dispersed in an aqueous dispersing medium. It is desirable in this reaction that the organosiloxane is absorbed by the organic polymer particles.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for producing composite particles of an inorganic polymer and an organic polymer, and more specifically to a method for producing particles in which an organic polymer is a continuous phase. The present invention relates to a method for producing polysiloxane composite polymer particles in which polysiloxane coexists.

0002

[Prior Art] Polysiloxane has excellent heat resistance, water resistance, organic chemical resistance, acid resistance, alkali resistance, weather resistance, and adhesion to inorganic substrates.
As disclosed in Japanese Patent No. 691, it is widely used in the fields of coating agents and the like.

However, when polysiloxane is used in a blend with other carbon-based polymers, it is difficult to exhibit the above-mentioned useful properties due to poor compatibility between the two, which limits the field of use.

[0004] In order to solve these problems and use polysiloxane for various purposes, a dispersion of a low molecular weight polysiloxane was prepared, and this was mixed with a dispersion of other organic polymers. A conceivable method is to combine the two by mixing the dispersion medium and the dispersion medium and then removing the dispersion medium. However, in this method, (1) the dispersion medium for dispersing the polysiloxane well is limited, and furthermore, it is necessary to add a dispersion aid to ensure stable storage for a long period of time, which makes it difficult to mix the polysiloxane with the organic polymer. Reduces compatibility.

[0005] Even if polysiloxane, which has poor compatibility to begin with, and other organic polymers are mixed as a dispersion, the resulting mixture will be non-uniform when the dispersion medium is removed. However, it does not necessarily have sufficient industrial utility value.

[0006]

[Problems to be Solved by the Invention] The present invention has been made against the above-mentioned background, and its purpose is that although it is highly useful, it has poor compatibility with organic polymers. It is an object of the present invention to provide a manufacturing method that can efficiently and easily manufacture polysiloxane composite polymer particles, which have conventionally been difficult to manufacture due to poor performance.

[0007]

[Means for Solving the Problems] The method for producing polysiloxane composite polymer particles of the present invention is characterized in that, in the presence of organic polymer particles dispersed in an aqueous dispersion medium, particles of the general formula Rn SiO (4-n)/2 (wherein R is a substituted or unsubstituted monovalent hydrocarbon group, n is an integer of 0 to 3) by proceeding with a condensation reaction of organosiloxane, The point is to obtain polymer particles in which polysiloxane is composited.

[0008]

[Operation] In the present invention, the organosiloxane represented by the above general formula is subjected to a condensation reaction in a system in which organic polymer particles are dispersed, so that the organosiloxane is adsorbed or absorbed by the organic polymer particles. As a result, particles in which the organic polymer and polysiloxane coexist can be efficiently obtained. Configuration The present invention will be described in detail below.

The organosiloxane used in the production method of the present invention has the general formula Rn SiO (4-n)/2
It has a structural unit represented by a chain,
It has a branched or cyclic structure, preferably an organosiloxane having a cyclic structure.

[0010] In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group, such as a methyl group, an ethyl group, a propyl group, a vinyl group, a phenyl group, and a substituted group such as a halogen atom or a cyano group. Examples include hydrocarbon groups.

[0011] In the above average composition formula, the value of n is 0 to 3.
is an integer.

Specific examples of the organosiloxane include hexaphenylcyclotrisiloxane, octaphenylcyclotetrasiloxane, tetravinyltetramethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, pentamethylcyclotetrasiloxane, In addition to cyclic compounds such as hexamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and trimethyltriphenylcyclotrisiloxane, linear or branched organosiloxanes may be mentioned. Can be done.

These organosiloxanes can be used alone or in combination of two or more, and can also be used in combination with other metal alkoxides such as titanium and aluminum. Moreover, these organosiloxanes can also be used after being dissolved in an organic solvent, if necessary.

In the present invention, the organic polymer particles function as seeds in the polymerization system, and the organosiloxane is preferably adsorbed or absorbed in the organic polymer particles (hereinafter referred to as "polymer seeds") before polymerization. be done.

[0015] The aqueous dispersion of polymer seeds is not particularly limited, and examples thereof include polystyrene latex, polybutadiene latex, and styrene-butadiene copolymer made of dispersed particles with an average particle diameter of 0.05 to 10 μm obtained by emulsion polymerization. Latex, acrylic ester copolymer latex, methacrylic ester copolymer latex, and any other known latex can be used. In addition, known re-emulsified Terrax, natural rubber Terrax, or a concentrate thereof, which is formed by redispersing a polymer obtained by solution polymerization or the like in water using an emulsifier, can also be used.

The amount of polymer seed used is preferably 0.001 to 100 parts by weight per 1 part by weight of organosiloxane.
0 parts by weight, more preferably 0.01 to 100 parts by weight.

The aqueous dispersion medium used in the production of the present invention can contain water alone or ketones, lower alcohols, esters, etc. that mix well with water. These organic solvents can be used at a ratio of about 1 to 100% relative to water, but in order to maintain a good dispersion state of the polymer seeds, they should be used at a ratio of 70% or less, preferably 50% or less. Preferably used in proportions.

In the present invention, absorption of the organosiloxane into the polymer seeds is easily achieved by adding the organosiloxane to an aqueous dispersion in which the polymer seeds are dispersed and stirring the system well. .

[0019] In order to efficiently absorb the organosiloxane into the polymer seed, if necessary, it is possible to previously absorb a solvent having a solubility in water of 10-3% by weight or less into the polymer seed. . In addition, the system was adjusted to pH 4
-10, preferably pH5-9, more preferably pH
6 to 8, and the temperature is 90°C or lower, preferably 70°C or lower, more preferably 50°C or lower, particularly preferably 30°C or lower.
It is desirable to add and absorb organosiloxane under conditions of ℃ or below.

The condensation reaction of organosiloxane can be easily controlled by adjusting the reaction temperature and hydrogen ion concentration, and the degree of polymerization of polysiloxane can be controlled.

[0021] The condensation reaction of organosiloxane can be carried out usually at a temperature of 30°C or higher, preferably 50°C or higher, more preferably 80°C or higher, and can be carried out, for example, in the presence of an emulsifier. This emulsifier serves as a surfactant and at the same time as a catalyst for the condensation reaction of organosiloxane, and aliphatic substituted benzenesulfonic acid is preferred as such an emulsifier.

In the present invention, the organosiloxane may be subjected to a condensation reaction while being absorbed into the polymer seed, or may be subjected to a condensation reaction while being adsorbed, for example, without being absorbed by the polymer seed. In order to obtain composite particles with excellent properties, it is preferable that the organosiloxane be absorbed into a polymer seed and subjected to a condensation reaction. The organosiloxane absorbed into the polymer seeds and subjected to the condensation reaction is preferably at least 5% by weight, more preferably at least 10% by weight, particularly preferably at least 30% by weight of the total organosiloxane used.

Next, the polymer particles obtained by the above-described production method of the present invention will be described.

The polymer particles obtained by the production method of the present invention are composite particles of an organic polymer constituting a polymer seed and a polysiloxane formed by condensation of an organosiloxane. Typical forms of these composite particles include islands or interpenetrating networks (IPN) of polysiloxane in a continuous phase of organic polymers constituting the polymer seeds, There is a structure in which they coexist in an encapsulated state where they are wholly or partially covered with polysiloxane.

The morphology of the polysiloxane in the composite polymer particles obtained by the production method of the present invention depends on the affinity between the organosiloxane used and the polymer seed, and the affinity between the polysiloxane obtained by condensation and the polymer seed. , as well as the amount ratio of polymer seed and polysiloxane.

Furthermore, when the average particle diameter of the composite polymer particles finally obtained becomes large, the dispersion stability of the aqueous dispersion decreases and the composite polymer particles coagulate, resulting in This poses a practical problem when used. The dispersion stability of composite polymer particles is affected by the density of the polymer particles, the viscosity of the aqueous dispersion medium, the concentration of solids, etc., but the particle diameter of the polymer particles is determined to be within the range in which the particles can move due to thermal motion. Such dispersion stability can be improved by setting the particle size to approximately 5 μm or less, preferably 2 μm or less, and more preferably 1 μm or less.

The composite polymer particles thus obtained may be used as they are as an inorganic-organic composite material, or
Depending on the case, the organic part may be removed by thermal decomposition or the like and used as inorganic particles.

[0028]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto.

Note that "parts" and "%" in the examples are expressed on a weight basis. <Example 1> In a reaction vessel equipped with a reflux condenser and a stirrer, 200 parts of distilled water, 65 parts of butadiene, 30 parts of styrene, 5 parts of acrylic acid, 0.5 parts of potassium persulfate, and 0.0 parts of sodium dodecylbenzenesulfonate were added. Prepare 5 parts, 60-8
Emulsion polymerization was carried out with stirring at 0° C. to obtain a styrene-butadiene copolymer latex as a dispersion of polymer seeds. 100 parts of this copolymer latex (weight equivalent to solid content) was placed in a reaction vessel equipped with a reflux condenser and a stirrer, and while the reaction vessel was maintained at 25°C, the pH of the dispersion was adjusted to 12.
Adjusted to 0. Then, 10 parts of tetramethylcyclotetrasiloxane was added and stirred vigorously for about 30 minutes. After that, the temperature of the reaction container was raised to 90°C and the reaction was carried out for 5 hours.
Cooled at 5°C for 48 hours. No coagulation was observed in the latex thus obtained. Furthermore, when this latex was left to stand for a long time, it was confirmed that a stable dispersion state could be maintained without separation of dispersed particles. <Example 2> Instead of 100 parts of the styrene-butadiene copolymer latex of Example 1, 1 styrene-butadiene latex "#0589" (manufactured by Japan Synthetic Rubber Co., Ltd.)
00 parts, tetramethylcyclotetrasiloxane 1
1 part of pentamethylcyclotetrasiloxane instead of 0 parts
An aqueous dispersion of polymer particles was obtained in the same manner as in Example 1, except that 0 part was used. <Example 3> Instead of 100 parts of the styrene-butadiene copolymer latex of Example 1, styrene-butadiene copolymer latex "#0545" (Japan Synthetic Rubber Co., Ltd.) was used.
An aqueous dispersion of polymer particles was obtained in the same manner as in Example 1, except that 100 parts of Polymer Co., Ltd.) and 10 parts of pentamethylcyclotetrasiloxane were used instead of 10 parts of tetramethylcyclotetrasiloxane. <Example 4> Acrylic ester copolymer latex "AE527" (manufactured by Japan Synthetic Rubber Co., Ltd.) was used instead of 100 parts of the styrene-butadiene copolymer latex of Example 1.
An aqueous dispersion of copolymer particles was obtained in the same manner as in Example 1, except that 1 part of octamethylcyclotetrasiloxane was used instead of 10 parts of tetramethylcyclotetrasiloxane. <Example 5> Instead of 100 parts of the styrene-butadiene copolymer latex of Example 1, acrylic ester copolymer latex "AE316 (A)" (Japan Synthetic Rubber Co., Ltd.
An aqueous dispersion of polymer particles was obtained in the same manner as in Example 1, except that 100 parts of octamethylcyclotetrasiloxane was used instead of 10 parts of tetramethylcyclotetrasiloxane. <Example 6> Acrylic ester copolymer latex "AE130" (manufactured by Japan Synthetic Rubber Co., Ltd.) was used instead of 100 parts of the styrene-butadiene copolymer latex of Example 1.
An aqueous dispersion of polymer particles was obtained in the same manner as in Example 1, except that 100 parts of tetramethylcyclotetrasiloxane was used and 50 parts of octamethylcyclotetrasiloxane was used instead of 10 parts of tetramethylcyclotetrasiloxane. <Example 7> Instead of 100 parts of the styrene-butadiene copolymer latex of Example 1, 100 parts of acrylic ester copolymer latex "AE513 (A)" (manufactured by Nippon Gosei Rubber Co., Ltd.) was used, and tetramethylcyclo An aqueous dispersion of polymer particles was obtained in the same manner as in Example 1, except that 10 parts of octamethylcyclotetrasiloxane was used instead of 10 parts of tetrasiloxane. <Example 8> Instead of 100 parts of the styrene-butadiene copolymer latex of Example 1, polystyrene latex "IMMUT" produced by soap-free polymerization was used.
EX'' (manufactured by Japan Synthetic Rubber Co., Ltd.) was used, and 10 parts of hexamethylcyclotrisiloxane was used instead of 10 parts of tetramethylcyclotetrasiloxane.
An aqueous dispersion of polymer particles was obtained in the same manner as in Example 1. <Comparative Example 1> 100 parts (solid content equivalent weight) of styrene-butadiene copolymer Terrax "#0589" (manufactured by Japan Synthetic Rubber Co., Ltd.) obtained by emulsion polymerization was diluted with distilled water to make 300 parts. <Comparative Example 2> Octamethylcyclotetrasiloxane 10
0 parts, 0.3 parts (solid weight equivalent) of sodium dodecylbenzenesulfonate with a concentration of 10% is diluted with distilled water to make 200 parts, placed in a reaction vessel equipped with a reflux condenser and a stirrer, and stirred well. Stir and mix. Thereafter, the temperature of the reaction vessel was raised to 70°C, and the reaction was carried out for 3 hours. Conversion rate 99%
A transparent aqueous polysiloxane dispersion was obtained.

Furthermore, 100 parts (solid content equivalent weight) of styrene-butadiene copolymer Terrax "#0589" (manufactured by Japan Synthetic Rubber Co., Ltd.) obtained by emulsion polymerization was diluted with distilled water to make 300 parts. 5.1 parts (weight equivalent to solid content) of the aqueous polysiloxane dispersion was mixed into the mixture to obtain a uniform aqueous dispersion. <Comparative Example 3> Instead of 100 parts of styrene-butadiene copolymer latex "#0589" in Comparative Example 2, acrylic ester copolymer Terrax "AE316(A)" (
An aqueous dispersion was obtained in the same manner as in Comparative Example 2, except that 100 parts (manufactured by Japan Synthetic Rubber Co., Ltd.) was used. <Comparative Example 4> In a reaction vessel, 5.1 parts of the aqueous dispersion of polysiloxane of Comparative Example 2 (solid content equivalent weight), 200 parts of distilled water, 65 parts of butadiene, 30 parts of styrene, 5 parts of acrylic acid, and potassium persulfate were added. 0.5 part was charged and emulsion polymerization was carried out with stirring at 60 to 80°C to obtain a copolymer latex.

As a result of observing the cross sections of the polymer particles obtained in Examples 1 to 8 using a transmission electron microscope, it was confirmed that polysiloxane was compounded within the particles.

Each of the aqueous dispersions of Examples 1 to 8 and Comparative Examples 1 to 4 above was applied to a substrate, and dried in a hot air dryer for 50 minutes.
This was left at 0° C. for 12 hours to form a film with a thickness of 2.0 mm. For the aqueous dispersions of Examples 4, 6, and 8, 20 parts of carbitol was added to form films. Regarding this film, the following items (1) to (3) were investigated, and the results shown in Table 1 were obtained. (1) Contact Angle of Water The contact angle was measured by dropping distilled water onto the film using a contact angle measuring device manufactured by Elma Optical Co., Ltd. (2) Adhesion test Adhesion was measured using the test method of JIS K5400. A galvanized iron plate was used as the substrate. The evaluation criteria for the test were as follows.

◎...No peeling○...Peeling is less than 10% of the total area△...Peeling is 10% or more and less than 50% of the total area×...Peeling is 50% or more of the total area (3) Weather resistance test Sunshine weather meter ( Manufactured by Suga Test Instruments Co., Ltd.
Dew Cycle WEL-SUN-DC type) was used to investigate the degree of yellowing after 300 hours of exposure. Yellowing degree is SM
Color computer (SM-5-1 manufactured by Suga Test Instruments Co., Ltd.)
S-3B type).

[0034]

[Table 1] As is clear from the results in Table 1, the polymer films of Examples include not only films containing no polysiloxane (Comparative Example 1) but also films containing copolymer latex and a dispersion of polysiloxane. Polymer film obtained by mixing (
The contact angle with water (water repellency) is larger than that of Comparative Examples 2 and 3) and the polymer film obtained by copolymerization in the presence of a polysiloxane dispersion (Comparative Example 4). In particular, when an acrylic ester copolymer is used as the organic polymer and 10 parts or more of octamethylcyclotetrasiloxane is used as the organosiloxane (Examples 5 to 7),
The effect is remarkable.

Furthermore, as is clear from the results in Table 1, the polymer films of Examples include not only films containing no polysiloxane (Comparative Example 1) but also films containing dispersions of copolymer latex and polysiloxane. It has much better adhesion than the polymer films obtained by mixing with (Comparative Examples 2 and 3). Particularly when using 10 to 50 parts of organosiloxane (Examples 1 to 3, 5, 6)
, 8), the effect is extremely remarkable.

Furthermore, as is clear from the results in Table 1, the polymer films of Examples had significantly better weather resistance than the film containing no polysiloxane (Comparative Example 1). ing. In particular, when 50 parts or more of organosiloxane is used (Examples 6 and 7), the effect is remarkable.

[0037]

Effects of the Invention According to the production method of the present invention, polysiloxane can be contained within the same particle by proceeding with a condensation reaction of a specific organosiloxane in the presence of organic polymer seeds dispersed in an aqueous dispersion medium. It is possible to easily produce an aqueous dispersion of polymer particles coexisting and composited in high yield.

The polysiloxane composite polymer obtained by the present invention is a polymer in which the excellent solvent resistance, heat resistance, weather resistance, and adhesion of polysiloxane are added to the organic polymer constituting the polymer seed. , can be used in a wide variety of applications. It is particularly suitable for applications where it is used in the form of an aqueous dispersion, such as paper coating compositions, carpet backing agents, asphalt compositions, foam rubbers, paints, adhesives, as well as rubbers or resins. It is effective in improving and modifying the strength and heat resistance of various materials.

Claims (1)

[Claims] Claim 1: In the presence of organic polymer particles dispersed in an aqueous dispersion medium, a compound having the general formula Rn SiO(4-n
)/2 (wherein, R is a substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 0 to 3). A method for producing polysiloxane composite polymer particles, the method comprising obtaining polysiloxane composite polymer particles.