JP3019302B2 - Method for producing polymer powder - Google Patents

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 coated with an inorganic substance.
It can also be referred to as an inorganic microcapsule using a polymer as a core substance and an inorganic substance as a wall material. Further, the polymer powder obtained by the present invention does not have tackiness, always maintains a fine particle form, and furthermore has excellent electrical insulation properties. Ease,
It can impart adhesiveness, surface durability or matting, etc., and when added to cement, imparts flexural strength, impact resistance or crack resistance to the cured product of the cement. It is used in the manufacture 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 awarded.

[0002]

2. Description of the Related Art A powder bed method, a charge pulverization method, a complex emulsion method and the like have been proposed 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. No satisfactory method has yet been found.

[0003] Further, these methods have a disadvantage that when inorganic fine particles are used as a starting material, the inorganic layer formed on the polymer surface often becomes incomplete, and a complicated process is required. It is often disadvantageous in terms of cost because it is necessary.

The inventor of the present invention has solved the above-mentioned problems and has disclosed a method of producing a polymer powder, comprising the steps of depositing a mixed solution of an inorganic sol and a polymer emulsion to obtain a slurry, washing and dewatering the slurry, and finally drying the slurry. The resulting polymer powder (Japanese Patent Application No. 3-234049) and a mixed solution of 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. And finally drying, and a polymer powder obtained by the method (Japanese Patent Application No. 3-99662).
No.) was proposed earlier.

[0005]

However, although the invention proposed above is an excellent solution to the conventional problems, in the invention of Japanese Patent Application No. Hei 3-234049, the inorganic materials that can be used are inorganic sols. Limited, inorganic fine particles having no sol form cannot be used, and in the invention of Japanese Patent Application No. 3-99662, inorganic fine particles having no sol form can be used as inorganic fine particles. It had disadvantages such as the necessity of using a material uniformly dispersed in water. The present inventors have conducted intensive studies to find a method 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 inventor has solved the above problem by adding non-sol-like inorganic fine particles to a mixed solution of a polymer emulsion and an inorganic sol and producing the mixture. Heading, the present invention has been completed.

That is, the present invention is characterized in that particles comprising a polymer and an inorganic material are separated from an aqueous dispersion obtained by adding non-sol-like inorganic fine particles to a mixed solution of a polymer emulsion and an inorganic sol. And 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 is easy to wash and remove inorganic ions. Thus, it is possible to produce a polymer powder having a very small amount of volatile components derived from water droplets mixed during the production. In addition, the polymer powder obtained by the present invention has a polymer as a core substance, has an inorganic coating derived from inorganic sol and non-sol inorganic fine particles, and has a porous surface. It is excellent in physical bondability with a resin to be modified, and when added to various resins, can give the resin an internal stress relaxation property based on foreign polymer fine particles. Hereinafter, the present invention will be described in detail.

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 polyolefin, polydiene, polyvinyl halide, polystyrene, a polymer of an unsaturated fatty acid or an ester thereof, a fatty acid vinyl polymer, an unsaturated nitrile polymer, a saturated polyester, nylon, or a polycarbonate or these. And the like. 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 the above thermoplastic polymer as a skeleton. Examples thereof include a polymer having a glycidyl group, a hydroxyl group, a carboxyl group, an amino group, or an allyl group, which has crosslinkability by heating, and a copolymer containing these as a constituent unit.

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

Further, in the present invention, the above-mentioned polymer emulsion, preferably a polymer of a rubber emulsion, or a polymer emulsion having silanol groups on the surface of rubber particles, or a polymer having a titanate or aluminum coupling agent adsorbed or bonded thereto. Preferably, an emulsion is used.

As the emulsion of the polymer having a silanol group, an alkoxysilane or a halogen silane having an acryloxy group, a methacryloxy group or a vinyl group is used in the presence of a polymer emulsion, in particular, a rubber emulsion. Those obtained by copolymerization with a single monomer or another monomer are preferred. Monomers when copolymerized with alkoxysilane or halogen silane, acrylonitrile, methacrylonitrile,
N-vinylpyrrolidone, N-vinylcaprolactam, acrylic acid ester, methacrylic acid ester, styrene, vinyltoluene and the like, acrylonitrile,
It is preferred to use methacrylonitrile. The emulsion thus obtained comprises a polymer having a polymer component at its 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 halogen silane having an acryloxy group, a methacryloxy group or a vinyl group include γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryl Oxypropyltris (trimethoxy) silane, vinyltrimethoxysilane,
Vinyl triethoxysilane, vinyl tris (methoxyethoxy) silane, vinyl trichlorosilane, and the like can be given.

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

Inorganic sol An inorganic sol is a colloidal solution in which inorganic ultrafine particles are dispersed in water. Examples of the inorganic substance 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.
mμ, and more preferably 5 to 50 mμ, and particularly preferably 5 to 20 mμ, from the viewpoint of facilitating the production of the polymer powder. Particularly preferred inorganic sol is an aqueous silica sol made of silica having an elongated shape with a thickness of 5 to 20 mμ and a length of 40 to 400 mμ, having a large thickening gelling property and easily forming a film. Further, those having a sodium oxide content of 1% or less are preferable because electric insulation can be imparted to a finally obtained product.

The amount of the inorganic sol to be 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 is less than 0.05 parts by weight, the polymer emulsion tends to gel when it is slurried, and it is difficult to make the polymer powder spherical, and on the other hand, If the amount exceeds 20 parts by weight, the resulting polymer powder will have poor affinity with the resin.

Non-Sol Inorganic Fine Particles The non-sol inorganic fine particles used in the present invention are inorganic fine particles that do not form a sol when dispersed in water. Examples of the inorganic fine particles include silica, alumina, zirconia, and the like. Metal oxides such as titanium oxide, iron oxide, antimony oxide or tin oxide, potassium salts of inorganic acids such as potassium titanate, barium titanate, calcium silicate, aluminum silicate, calcium carbonate, magnesium carbonate, magnesium hydroxide, Hydroxides such as aluminum hydroxide, carbon black, aluminum nitride, boron nitride, silicon nitride, fine particles such as silicon carbide or molybdenum disulfide can be mentioned, from the viewpoint that it is easy to carry, silica, alumina in the present invention, Fine particles of titanium oxide are preferred. In particular, in the present invention, the use of the fine particles of the inorganic ion exchanger as the non-sol-like 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. Specifically, preferred are clay minerals such as kaolinite and montmorillonite, zeolites, insoluble oxides such as hydrous titanium oxide, antimony hydroxide, hydrous bismuth, hydrous zirconium oxide, etc. Insoluble acid salts such as zirconium phosphate, titanium phosphate and tin phosphate can be exemplified. Cation, as the fine particles of the ion exchanger,
It is preferable to use zwitterion-exchangeable ion exchanger particles capable of simultaneously removing both anion and anion.

As these non-sol inorganic fine particles, those having a primary particle diameter of 1 μm to 200 μm are preferably used. Those having a particle diameter of less than 1 μm have a high viscosity, so that it is difficult to support the inorganic fine particles on the surface of the polymer particles because of a high viscosity, and those having a particle diameter of more than 200 μm are difficult to be dispersed in water and supported. Should also be avoided because it becomes difficult.

In the present invention, several kinds of non-sol inorganic fine particles can be used in combination.

The amount of the non-sol inorganic fine particles used is 5 to 200 parts by weight per 100 parts by weight of the solid content of the polymer emulsion.
It is preferably from 10 to 100 parts by weight, more preferably from 10 to 100 parts by weight. When the amount of the non-sol inorganic fine particles is less than 5 parts by weight, it is difficult to obtain fine powders, while when it exceeds 200 parts by weight, the elasticity of the produced polymer powder is remarkably large. This makes it difficult to impart stress relaxation 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 one produced by generally known means. For example, the polymer emulsion may be mixed with the inorganic sol under stirring at a relatively low speed. What is obtained by the method which stirs for about 10 minutes to 1 hour after putting in 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 are also used for adding a non-sol-like inorganic fine particle to a mixed solution of a polymer emulsion and an inorganic sol to form an aqueous dispersion.
There is a method in which non-sol-like inorganic fine particles are charged under relatively low-speed stirring. Here, when an inorganic ion exchanger is used as the non-sol inorganic fine particles, the polymer emulsion is slurried. When using other than the inorganic ion exchanger as the non-sol-like inorganic fine particles, the above aqueous dispersion is gradually added to the aqueous solution in which the flocculant is dissolved under relatively high stirring, or the aqueous dispersion is subjected to ion exchange. A slurry can be formed by adding a substance and stirring the mixture. When a coagulant is used at the time of slurrying, it is preferable to use a water-soluble polymer as the coagulant.
In particular, in the present invention, it is preferable to adopt a method of forming a slurry using an ion exchanger because inorganic ions in the emulsion can be reduced. In this case, any organic or inorganic ion exchanger can be used as the ion exchanger. When the ion exchanger is not supported on a polymer, it is preferable to use bead-like particles having a relatively large particle size.In addition, non-sol inorganic fine particles other than the inorganic ion exchanger and the inorganic ion exchanger are simultaneously converted into a polymer. When supported, it is preferable to use an inorganic ion exchanger having a primary particle size of 1 μm to 200 μm.

The slurry is filtered to remove coarse particle suspended matters or bead-like ion exchangers, then passed through a nozzle type or centrifugal type spray drier and dried while being dispersed in the form of a mist. The coalesced and inorganic particles can be separated, and thus the finely divided polymer powder having a volatile content of 0.5% by weight or less and a particle size of 100 μ or less, having the inorganic material supported on the surface or coated with the inorganic material, is obtained. can get. When the non-sol-like inorganic fine particles to be supported are inorganic ion exchangers, a slurry is formed and then spray-dried to obtain a polymer powder on which the inorganic ion exchanger is supported. The polymer powder thus obtained is easy to handle and can be used for a wide range of applications.

Use Method The polymer powder obtained according to the present invention is added to various resins to improve the stress relaxation property, adhesiveness, surface durability or matting property of those resins, and to be added to cement. When the resin is in a liquid state, it is used to improve the flexural strength, impact resistance or crack resistance of the cured product of the cement. When adding to the resin, it is only necessary to 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-sol inorganic fine particles are used as a wall material. This is because the surface of the polymer emulsion in the mixture of the sol and the inorganic sol has the inorganic sol adsorbed thereon, thereby improving the affinity with the non-sol inorganic fine particles. Further, the polymer powder obtained by the present invention, the surface is supported or coated with non-sol inorganic fine particles, the anchor effect is excellent because the surface is porous compared to the case of manufacturing only inorganic sol,
It 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 with reference to the following examples.

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

Further, 19.2 gr of Levenol WZ, 0.5 gr of potassium persulfate, 60 gr of styrene, 30 gr of acrylonitrile and 10 gr of NUC silane monomer A-171 (vinyltrimethoxysilane, manufactured by Nippon Unicar Co., Ltd.) were charged at 5 ° C. at 5 ° C. When the emulsion polymerization was continued for a period of time, a polymer emulsion having a solid content of 36% by weight was obtained, in which a butyl acrylate / butadiene copolymer was used as a core and a shell part was a styrene / acrylonitrile copolymer having silanol groups bonded thereto.

Production of Polymer Powder 830 gr of the above-mentioned polymer emulsion 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
-2 gr of decyne-4,7-diol 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, Nissan Chemical Co., Ltd.)
) Was gradually added thereto, and stirring and mixing were continued at 40 to 45 ° C for 1 hour.

Next, the mixed solution was transferred to a 10-liter stainless steel mixing tank, and pure water 3820 was stirred (400 rpm).
cc, followed by 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 (mixed cation and anion ion exchanger binding sulfonic acid and quaternary amine group, particle size 0.40
1.19 mm, manufactured by Organo Co., Ltd.)
Stirring was continued at C for 3 hours.

The resulting mixture was passed through a 100-mesh cloth to remove the ion-exchange resin, and the resulting slurry mixture was dried as it was by passing it through a disk-type spray dryer. A polymer powder 605 of a copolymer (47% by weight) containing butyl acrylate / butadiene as a main component and having silica (53% by weight) supported on its surface;
got gr.

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

With respect to the integrated circuit component prototyped above, the liquid phase was subjected to a thermal cycle condition of -65 to + 150 ° C. under a thermal change cycle of 3 to 3.
The crack generation rate (%) after 000 cycles was observed.
The evaluation results are as shown in Table 1.

[0033]

[Table 1]

Comparative Example 1 The same operation as in Example 1 was carried out except that Snowtex UP was not used, and the obtained powder was coarse particles having a particle diameter 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, 1000 cc of pure water and Gohsenol GM-14 (partially saponified PVA having a saponification degree of 86 mol% and an average polymerization degree of 1400, Nippon Synthetic Chemical Industry Co., Ltd.) ), 10 gr of potassium persulfate, 10 gr of acrylic acid, 190 gr of vinyl acetate and 300 gr of ethylene, 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, 19.2 g of Levenol WZ was further added.
r, 0.5 gr of potassium persulfate, 66 gr of styrene, 30 gr of acrylonitrile and NUC silane monomer A-174
(Γ-methacryloxypropyltrimethoxysilane, manufactured by Nippon Unicar Co., Ltd.)
When the emulsion polymerization was continued for a period of time, a polymer emulsion having a solid content of 34% by weight was obtained in which an acrylic acid / vinyl acetate / ethylene copolymer was used as a core and a shell portion was used as a styrene / acrylonitrile copolymer having a silanol group. .

Production of Polymer Powder In Example 1, 879 gr of the above-mentioned polymer emulsion, 38 gr of Snowtex UP,
Anhydrosilica "Aerosil 200" (Primary particle size 2-10
mμ, manufactured by Nippon Aerosil Co., Ltd.) and 15 g of IXE-600 (antimony, bismuth-based inorganic ion exchanger, particle size: 0.2-2 μm, manufactured by Toagosei Chemical Industry Co., Ltd.) as an ion exchanger. In the same way,
When silica sol and silica fine powder were loaded, the particle size was 5 to 50 μm, and silica and inorganic ion exchanger (1
Polymer powder of vinyl acetate / ethylene-based copolymer (88.9% by weight) loaded with 1.1% by weight)
0 gr was obtained.

Table 3 shows the results of evaluation 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 method for producing a polymer powder of the present invention,
Even when inorganic fine particles other than sol are used as the raw material of the inorganic layer, a fine polymer powder can be produced. In addition, the polymer powder produced by the method for producing a polymer powder of the present invention has a very low volatile content, and further has a porous surface with non-sol inorganic fine particles supported thereon. ) When blended with a wide range of resins such as acrylic resin, polyimide resin, polyphenylene sulfide resin, polyester resin or silicone resin, imparts internal stress relaxation, adhesion, surface durability or matting to the resin. When blended with cement, it can impart flexural strength, impact resistance or cracking resistance to the cured product of the cement, especially for semiconductor device sealants, structural adhesives or durability. It is useful as a modifier for paint bases.

Claims (1)

(57) [Claims] 1. A polymer powder comprising separating a polymer and an inorganic particle from an aqueous dispersion obtained by adding a non-sol inorganic fine particle to a mixture of a polymer emulsion and an inorganic sol. Manufacturing method.