JPH0532790A - Production of polymer powder - Google Patents

Abstract

PURPOSE:To obtain polymer powder capable of imparting excellent performance by its blending in various resins or cement due to its low volatile content and porous surface by using inorganic fine particles in a nonsol state. CONSTITUTION:A polymer emulsion (e.g. a rubber emulsion such as an acrylic rubber or acrylonitrile-butadiene rubber) and ultrafine particles such as an inorganic substance (e.g. silica or alumina) are dispersed in water to provide a mix liquid composed of the polymer emulsion and an inorganic sol in an amount of 0.05-20 pts.wt. based on 100 pts.wt. solid content of the polymer emulsion. Nonsol-like inorganic fine particles (e.g. silica or alumina) in an amount of 5-200 pts.wt. based on 100 pts.wt. solid content of the polymer emulsion are blended with the aforementioned mixture. The resultant polymer powder is capable of imparting internal stress relaxing properties, adhesion, surface durability or delustering properties, etc., to a resin by blending with the resin. Flexural strength, impact and crack resistance, etc., are imparted to hardened cement by blending with the cement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a finely divided polymer powder whose surface is supported or covered with an inorganic substance, and the powder obtained by the present invention is
It can also be referred to as an inorganic microcapsule having a polymer as a core substance and an inorganic as a wall material. Further, the polymer powder obtained by the present invention does not have tackiness, always maintains a fine particle morphology, and further has excellent electrical insulating properties. Therefore, when blended with various resins, the internal stress of the resin is Ease,
Adhesiveness, surface durability, mattness, etc. can be imparted, and when blended with cement, it must impart flexural strength, impact resistance or crack resistance to the cured product of the cement. It is used for the production of adhesives, paints, encapsulants for semiconductor devices, engineering plastic base materials, etc., or as a modifier for mortar or concrete base materials. It can be prized.

[0002]

2. Description of the Related Art As a method of supporting inorganic fine particles on the surface of polymer particles or coating the surface of polymer particles with inorganic fine particles, powder bed method, electrostatic pulverization method, complex emulsion method and the like have been proposed. Has not yet been found.

Further, in these methods, when inorganic fine particles are used as a starting material, there is a drawback that the inorganic layer formed on the surface of the polymer is often incomplete, and a complicated process is required. It is often costly because it is necessary.

The inventor of the present invention solves the above-mentioned problems by preparing a mixed solution of an inorganic sol and a polymer emulsion to obtain a slurry, washing and dehydrating the slurry, and finally drying the polymer powder. The polymer powder thus obtained (Japanese Patent Application No. 3-234049) and a non-sol dispersion of inorganic fine particles and a polymer emulsion having a silanol group are precipitated to obtain a slurry, which is washed and dehydrated. Then, a method for producing a polymer powder, which is followed by drying, and a polymer powder obtained thereby (Japanese Patent Application No. 3-99662).
No.) was previously proposed.

[0005]

However, the previously proposed invention is an excellent solution to the conventional problems, but in the invention of Japanese Patent Application No. 3-234049, the usable inorganic substance is an inorganic sol. Limited, it is not possible to use inorganic fine particles having no sol form, and in the invention of Japanese Patent Application No. 3-99662, inorganic fine particles not having a sol form can be used as the inorganic fine particles, but usable inorganic fine particles are It has a drawback that it is necessary to use a material uniformly dispersed in water. The present inventor has conducted earnest studies to find a method capable of producing a polymer powder having better performance than the previously proposed polymer powder by using inorganic fine particles having no sol form.

[0006]

Means for Solving the Problems The present inventors can solve the above problems by adding and mixing non-solated inorganic fine particles to a mixed solution of a polymer emulsion and an inorganic sol to produce the same. Heading, completed the present invention.

That is, the present invention is characterized in that particles composed of a polymer and an inorganic substance are separated from an aqueous dispersion obtained by adding non-solated inorganic fine particles to a mixed liquid of a polymer emulsion and an inorganic sol. The present invention relates to a method for producing a polymer powder.

The method for producing a polymer powder according to the present invention makes it possible to produce a finely divided polymer powder, and it is easy to wash and remove inorganic ions. Thus, it is possible to produce a polymer powder having an extremely small amount of volatile components derived from water droplets mixed in during the production. Further, the polymer powder obtained by the present invention has a polymer as a core substance and has an inorganic coating derived from inorganic sol and non-sol type inorganic fine particles, and since its surface is porous, it is modified by a physical anchor effect. It has an excellent physical bondability with the resin to be obtained, and when it is mixed with various resins, it can impart the internal stress relaxation property based on the different polymer fine particles to the resin. The present invention will be described in detail below.

Polymer emulsion The polymer emulsion that can be used in the present invention is an emulsion of a conventionally known thermoplastic polymer or thermosetting polymer with an anionic, cationic or nonionic surfactant. Examples of the thermoplastic polymer include polyolefins, polydienes, polyvinyl halides, polystyrenes, polymers of unsaturated fatty acids or their esters, fatty acid vinyl polymers, unsaturated nitrile polymers, saturated polyesters, nylons or polycarbonates or these. And the like. Further, as the thermosetting polymer, a urea resin, a phenol resin, a melamine resin, a polyurethane, an epoxy resin, a silicone resin, a glyptal resin, an alkyd resin, a polyallyl resin, a reactive polyester resin, or a thermoplastic polymer as a skeleton is used. Examples thereof include a polymer having a crosslinkable glycidyl group, a hydroxyl group, a carboxyl group, an amino group or an allyl group, or a copolymer having these as a constituent unit.

In the present invention, as a polymer emulsion,
It is preferable to use a rubber emulsion, specifically, acrylic rubber, acrylonitrile-butadiene rubber,
Examples thereof include rubber emulsions such as styrene-butadiene rubber, styrene-isoprene rubber, styrene-propylene-diene terpolymer rubber and ethylene-vinyl acetate rubber.

Further, in the present invention, a polymer emulsion, preferably a polymer of a rubber emulsion or a polymer emulsion having a silanol group on the surface of a rubber particle, or a polymer having a titanate-based or aluminum-based coupling agent adsorbed or bound thereto. Preference is given to using emulsions.

As the emulsion of the polymer having a silanol group, alkoxysilane or halogensilane having an acryloxy group, a methacryloxy group or a vinyl group in the presence of a polymer emulsion, particularly a rubber emulsion, is used. Those obtained by homopolymerization or copolymerization with other monomers are preferable. As a monomer when copolymerized with an alkoxysilane or a halogensilane, acrylonitrile, methacrylonitrile,
N-vinylpyrrolidone, N-vinylcaprolactam, acrylic acid ester, methacrylic acid ester, styrene, vinyltoluene and the like, acrylonitrile,
Preference is given to using methacrylonitrile. The emulsion thus obtained comprises a polymer having a polymer component in the core and a silanol group on the outer wall, and is called a core-shell type polymer emulsion. The polymer having a silanol group on the outer wall is preferably a polymer having a glass transition temperature of 50 to 200 ° C. Specific examples of the alkoxysilane or halogensilane having an acryloxy group, a methacryloxy group or a vinyl group include γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and γ-methacryl. Oxypropyltris (trimethoxy) silane, vinyltrimethoxysilane,
Examples thereof include vinyltriethoxysilane, vinyltris (methoxyethoxy) silane and vinyltrichlorosilane.

The particle size of these polymer emulsions can be changed according to the particle size of the polymer powder finally obtained, but the particle size of the polymer powder of 100 μm or less has a wide range of uses. Therefore, as the polymer emulsion, it is preferable to use a polymer having a particle size of 30 μm or less, more preferably 10 μm or less, and particularly preferably 0.1 to 3 μm.

○ Inorganic sol An inorganic sol is a colloidal solution in which ultrafine inorganic particles are dispersed in water, and examples of the inorganic sol include silica, alumina, titanium oxide, iron oxide, antimony oxide, tin oxide and zirconia. it can. The inorganic particle diameter in these inorganic sols is preferably 1 to 400.
The particle size is more preferably 5 μm to 50 mμ, and particularly preferably 5 to 20 mμ in terms of facilitating the production of the polymer powder. A particularly preferred inorganic sol is an aqueous silica sol having a thickness of 5 to 20 m [mu] and a length of 40 to 400 m [mu], which has an elongated shape, has a large thickening gelation property, and easily forms a film. Further, it is preferable that the content of sodium oxide is 1% or less, since the product finally obtained can be provided with electric insulation.

The amount of the inorganic sol used is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the solid content of the polymer emulsion. If the amount of the inorganic sol used is less than 0.05 parts by weight, gelation tends to occur when the polymer emulsion is slurried, and it becomes difficult to make the polymer powder into a spherical shape. If it exceeds 20 parts by weight, the polymer powder obtained will have poor affinity with the resin.

Non-sol-like inorganic fine particles The non-sol-like inorganic fine particles used in the present invention are inorganic fine particles which do not become a sol state when dispersed in water, and the inorganic fine particles include silica, alumina, zirconia, Metal oxides such as titanium oxide, iron oxide, antimony oxide or tin oxide, potassium titanate, barium titanate, calcium silicate, aluminum silicate, calcium carbonate, magnesium carbonate and other inorganic acid salts, magnesium hydroxide, Hydroxides such as aluminum hydroxide, carbon black, aluminum nitride, boron nitride, silicon nitride, silicon carbide or fine particles such as molybdenum disulfide can be mentioned, from the viewpoint of easy loading, silica, alumina in the present invention, Fine particles of titanium oxide are preferred. In particular, in the present invention, the use of fine particles of an inorganic ion exchanger as the non-sol type inorganic fine particles can reduce the inorganic ions in the produced polymer powder and can remove the inorganic ions in the resin to be modified. So preferable, specifically, kaolinite, clay minerals such as montmorillonite, zeolites, hydrous titanium oxide, hydrous antimony oxide, hydrous bismuth oxide, hydrous zirconium oxide and other insoluble oxides or hydrous acid compounds, phosphorus. Examples thereof include insoluble acid salts such as zirconium acid, titanium phosphate, and tin phosphate. As the fine particles of the ion exchanger, cations,
It is preferable to use ion-exchange particles having both ion-exchange properties and capable of simultaneously removing both anions and ions.

As these non-sol type inorganic fine particles, those having a primary particle diameter of 1 mμ to 200 μ are preferably used. When the dispersion liquid is less than 1 mμ, it is difficult to support the inorganic fine particles on the surface of the polymer particles when the dispersion liquid has a high viscosity, and when the dispersion liquid exceeds 200 μ, it is difficult to disperse in the water, and it is required to be supported. It will be difficult, so it is better to avoid it.

In the present invention, it is possible to use several kinds of non-sol type inorganic fine particles in combination.

The amount of the non-solar inorganic fine particles used is 5 to 200 with respect to 100 parts by weight of the solid content of the polymer emulsion.
The amount is preferably 10 parts by weight, more preferably 10 to 100 parts by weight. When the amount of the non-solated inorganic fine particles used is less than 5 parts by weight, it becomes difficult to obtain a finely divided powder, while when it exceeds 200 parts by weight, the elasticity of the polymer powder produced is extremely large. Therefore, it becomes difficult to impart stress relaxation property to the resin to be modified.

Production Method The mixed solution of the polymer emulsion and the inorganic sol used in the present invention may be produced by a generally known means. For example, the polymer emulsion may be mixed with the inorganic sol at a relatively low speed with stirring. The thing obtained by the method of stirring for about 10 minutes to 1 hour after charging is mentioned. In this case, it is preferable to add an antifoaming agent in order to avoid foaming, entrainment of air, and formation of suspended matter during stirring. Although various antifoaming agents can be used, it is preferable to use an acetylene alcohol compound.

Various methods can be adopted as a method of adding non-solated inorganic fine particles to a mixed solution of a polymer emulsion and an inorganic sol to prepare an aqueous dispersion. For example, in the above mixed solution,
A method of adding the non-solar inorganic fine particles while stirring at a relatively low speed can be mentioned. When an inorganic ion exchanger is used as the non-sol type inorganic fine particles, the polymer emulsion is slurried. When using something other than an inorganic ion exchanger as the non-sol type inorganic fine particles, the above aqueous dispersion is gradually added to an aqueous solution in which the aggregating agent is dissolved under relatively high stirring, or ion exchange is performed on the aqueous dispersion. A body can be added and stirred to form a slurry. When a flocculant is used for forming a slurry, it is preferable to use a water-soluble polymer as the flocculant.
Particularly in the present invention, it is preferable to employ a method of making a slurry by using an ion exchanger, because the inorganic ions in the emulsion can be reduced. In this case, either an organic or inorganic ion exchanger can be used as the ion exchanger. When the ion exchanger is not supported on the polymer, it is preferable to use bead-shaped particles having a relatively large particle size, and non-sol inorganic fine particles other than the inorganic ion exchanger and the inorganic ion exchanger are simultaneously formed on the polymer. When carrying it, it is preferable to use an inorganic ion exchanger having a primary particle diameter of 1 mμ to 200μ.

The above-mentioned slurry is dried by removing coarse particle suspensions or bead-like ion exchangers by filtration or the like, and then passing through a nozzle type or centrifugal type spray dryer to disperse the particles in a mist state. It is possible to separate the coalescent particles from the inorganic particles. Thus, a finely powdered polymer powder having a volatile content of 0.5% by weight or less and a particle size of 100 μ or less, in which the surface of the inorganic material is covered or coated with the inorganic material is obtained. can get. When the non-solar inorganic fine particles to be carried are inorganic ion exchangers, a polymer powder carrying the inorganic ion exchangers can be obtained by making the slurry and then spray-drying as it is. Since the polymer powder thus obtained is easy to handle, it can be used in a wide range of applications.

Method of Utilization The polymer powder obtained by the present invention is added to various resins to improve the stress relaxation property, the adhesive property, the surface durability or the matting property of those resins, and is added to the cement. When it is applied, it improves the bending strength, impact resistance, crack resistance, etc. of the cured product of the cement. The method of adding the polymer powder is when the resin is liquid and When it is added to the above, simply add and stir with a conventional stirrer.If the resin is in a solid state, it may be melted or made into a liquid state using a solvent, and similarly added and mixed. ..

[0024]

According to the method for producing a polymer powder of the present invention, a fine polymer powder can be produced even when non-solar inorganic fine particles are used as a wall agent because the polymer emulsion used in the present invention is used. This is because the inorganic sol is adsorbed on the surface of the polymer emulsion in the mixed solution of the sol and the inorganic sol, which improves the affinity with the non-sol type inorganic fine particles. Further, the polymer powder obtained by the present invention, the surface is supported or coated with non-solar inorganic fine particles, excellent anchor effect because the surface is porous compared to when produced only with an inorganic sol,
Can impart internal stress relaxation, adhesiveness, surface durability, etc. of the resin to be modified, and impart bending strength, impact resistance or crack resistance to the cement to be modified. Can be done.

[0025]

The present invention will be described in more detail based on the following examples.

Example 1. ○ Synthesis of polymer emulsion 1000 cc of pure water in a 2 L stainless steel autoclave, Rebenol WZ (26% aqueous solution of sodium polyoxyethylene alkylphenyl ether sulfate; manufactured by Kao Corporation)
19.2 gr, potassium persulfate 2.5 gr, tertiary dodecyl mercaptan 1.0 gr, butyl acrylate 250 gr and butadiene 250 gr were charged, and emulsion polymerization was carried out at 50 ° C. for 15 hours while stirring with a propeller type stirring blade (350 rpm). It was

Furthermore, lebenol WZ19.2gr, potassium persulfate 0.5gr, styrene 60gr, acrylonitrile 30gr and NUC silane monomer A-171 (vinyltrimethoxysilane, manufactured by Nippon Unicar Co., Ltd.) 10gr were charged and the mixture was heated at 70 ° C. for 5 hours. When emulsion polymerization was continued for a time, a polymer emulsion having a solid content of 36% by weight, having a butyl acrylate / butadiene copolymer as a core and a shell portion as a styrene / acrylonitrile copolymer having a silanol group bonded thereto, was obtained.

Preparation of Polymer Powder The above polymer emulsion 830 gr was charged into a 2 liter beaker and stirred with a propeller type stirring blade (300 rp).
m), 2,4,7,9-tetramethyl-5 as an antifoaming agent
-Decine-4,7-diol 2 gr was added, and Snowtex UP (solid content 20% by weight, rod-shaped silica sol having a thickness of 5 to 20 mμ and a length of 40 to 300 mμ, manufactured by Nissan Kagaku Co., Ltd.)
(Manufactured by K.K.) was gradually added, and stirring and mixing were continued at 40 to 45 ° C. for 1 hour.

Next, the mixed solution was transferred to a stainless steel mixing tank of 10 liters, and stirred under pure water (400 rpm) 3820.
cc was added, and then silica fine powder “Glass Grain SG-
A "(fused silica powder having a particle size of 0.5 to 20 μm, manufactured by Toshiba Ceramics Co., Ltd.) 323 gr, Amberlite IRN-
150 (cation and anion mixed type ion exchanger binding sulfonic acid and quaternary amine group, particle size 0.40
1.19 mm, made by Organo Co., Ltd.) 63 gr, 50
Stirring was continued for 3 hours at ° C.

The obtained mixed solution was passed through a 100-mesh cloth to remove the ion exchange resin, and the obtained slurry mixture was dried as it was in a disc-type spray dryer to give a particle size of 1 to 20 μm. , Polymer powder 605 of butyl acrylate / butadiene-based copolymer (47 wt%) carrying silica (53 wt%) on the surface
got gr

Performance Evaluation The obtained polymer powder was evaluated as follows. The obtained polymer powder and fused silica having a particle size of 3 to 120 μm as an inorganic filler were used, epoxy equivalent 190, epoxy resin 100 parts by weight having a softening point of 80 ° C., phenol equivalent 130, and softening point 8
A composition comprising 50 parts by weight of a phenol novolac resin at 0 ° C., 0.5 parts by weight of 2-methylimidazole and 0.5 parts by weight of stearic acid was blended as shown in Table 1, mixed with a lab mixer, and further mixed at 80-90. The mixture was melt-mixed for 3 minutes on a hot roll at ℃, and then cooled and ground. 18p using the above composition
Transfer molding of inDIP (package width 8.88mm, element occupation area ratio 60%) (175 ℃, 30kg / c)
m ² for 3 minutes), and further cured by heating at 175 ° C. for 4 hours.

With respect to the integrated circuit parts produced as prototypes as described above, the liquid phase was subjected to a thermal change cycle condition of −65 to + 150 ° C.
The crack generation rate (%) after 000 cycles was observed.
The evaluation results are shown in Table 1.

[0033]

[Table 1]

Comparative Example 1 When the same operation as in Example 1 was carried out except that Snowtex UP was not used, the obtained powder was coarse particles having a particle size of 0.1 to 0.5 mm. The results of evaluating the coarse particles in the same manner as in Example 1 are shown in Table 2.

[0035]

[Table 2]

Example 2 Synthesis of polymer emulsion In a 2 L stainless steel autoclave, pure water 1000 cc, Gohsenol GM-14 (saponification PVA with saponification degree 86 mol%, average polymerization degree 1400, Nippon Synthetic Chemical Industry Co., Ltd.) 10 gr, 10 gr of potassium persulfate, 10 gr of acrylic acid, 190 gr of vinyl acetate and 300 gr of ethylene were charged, and emulsion polymerization was carried out at 50 ° C. for 20 hours while stirring (400 rpm) with a propeller-type stirring blade. After purging the remaining ethylene gas, lebenol WZ19.2g
r, potassium persulfate 0.5 gr, styrene 66 gr, acrylonitrile 30 gr and NUC silane monomer A-174
(Γ-methacryloxypropyltrimethoxysilane, manufactured by Nippon Unicar Co., Ltd.) 4 gr was charged, and the mixture was heated at 70 ° C. for 5 hours.
When emulsion polymerization was continued for a period of time, a polymer emulsion having a solid content of 34% by weight, having an acrylic acid / vinyl acetate / ethylene copolymer as a core and a shell portion as a styrene / acrylonitrile copolymer having a silanol group, was obtained. ..

Production of Polymer Powder In Example 1, the polymer emulsion was added to the above polymer emulsion 879 gr, Snowtex UP 38 gr,
Anhydrous silica "Aerosil 200" (primary particle size 2-10
mμ, manufactured by Nippon Aerosil Co., Ltd. 15gr, and IXE-600 (antimony, bismuth-based inorganic ion exchanger, particle size 0.2-2μ, manufactured by Toagosei Co., Ltd.) 15gr as ion exchangers In the same way,
When silica sol and silica fine powder were carried, the particle size was 5 to 50 μm, and silica and inorganic ion exchanger (1
Polymer powder 32 of vinyl acetate / ethylene-based copolymer (88.9% by weight) carrying 1.1% by weight)
I got 0 gr.

Table 3 shows the evaluation results obtained in the same manner as in Example 1 except that low soda alumina fine powder having a particle size of 2 to 10 μm was added as an inorganic filler to the obtained polymer powder. ..

[0039]

[Table 3]

[0040]

According to the polymer powder production method of the present invention,
Even when inorganic fine particles other than sol are used as the raw material for the inorganic layer, finely divided polymer powder can be produced. Further, the polymer powder produced by the method for producing a polymer powder of the present invention has an extremely small amount of volatile matter, and since the surface is supported by non-sol type inorganic fine particles and is porous, the epoxy resin, (meth ) When blended with a wide range of resins such as acrylic resins, polyimide resins, polyphenylene sulfide resins, polyester resins or silicone resins, it must impart internal stress relaxation, adhesiveness, surface durability or matteness to the resins. When it is added to cement, it is possible to impart flexural strength, impact resistance or crack resistance to the cured product of the cement, and in particular, it is a sealant for semiconductor devices, a structural adhesive or durability. It is useful as a modifier for paint base materials.

Claims (1)

What is claimed is: 1. Separation of polymer and inorganic particles from an aqueous dispersion obtained by adding non-solated inorganic fine particles to a mixed solution of a polymer emulsion and an inorganic sol. A method for producing a polymer powder, which is characterized.