JP2844886B2 - Polymer powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Object of the Invention [Industrial Application Field] The present invention relates to a fine rubber powder having an inorganic material supported on the surface thereof. Acrylic resin, 2-cyanoacrylate resin,
By blending with a polyphenylene sulfe feed resin, a phenol resin or a polyimide resin, a resin composition having excellent internal stress relaxation properties and heat resistance can be obtained.

[Conventional technology]

Resins such as epoxy resin, methacrylic resin, 2-cyanoacrylate resin, polyphenylene sulfide resin, phenolic resin, polyimide resin, or liquid crystal polymer, depend on their properties, that is, excellent adhesiveness, insulation, heat resistance or moisture resistance. In addition, it is widely used as a molding material, an adhesive material, or a package of electronic materials.

However, these resins are not completely satisfactory in toughness.In particular, when there is a temperature change, internal stress due to the thermal expansion property of the component occurs, and the resin itself cracks or adheres. Peeling is likely to occur depending on the interface with the material.

For this purpose, various rubbers such as fine particle silicone rubber or plasticizers such as fluid silicone oil are frequently added. By these, the toughness of the resin is improved to some extent, but these additives are difficult to disperse in the resin, are insufficient to improve the crack resistance, and when rubber is added, the elasticity of the resin itself,
When the heat resistance or heat resistance is reduced, or when a plasticizer such as silicone oil is added, bleeding easily occurs at the interface between the components, and there are problems such as peeling between the package and the substrate, dirt on the surface, or poor printability. That is the current situation.

[Problems to be solved by the invention]

When rubber is added to epoxy resin, methacrylic resin, 2-cyanoacrylate resin, polyphenylene sulfide resin, phenol resin, polyimide resin or liquid crystal polymer to improve the toughness or relieve internal stress, elasticity or heat resistance In order not to lower the rubber, it is preferable to finely disperse the rubber to form a so-called sea-island structure, but because of the properties of the rubber, that is, due to its tackiness, the rubber is uniformly dispersed as fine particles in these resins. It is difficult to do so, and when rubber is added to these resins, the rubber must be dissolved or dispersed in the form of coarse particles, thereby reducing the elasticity or heat resistance of the resin. Therefore, various investigations have been made to obtain rubber particles, particularly fine particles, and as an anti-adhesive agent, talc,
It has been proposed to use silica, vinyl chloride or acrylonitrile polymer, calcium stearate, etc., but in their use, rubber particles are limited to about several hundred μ, and re-agglomeration under pressure, Only those that were difficult to uniformly disperse in the resin could be produced.

The present inventors have found that an organic polymer powder having a particle size capable of improving toughness, which is added to a finely divided organic polymer, particularly a resin having poor toughness, without substantially reducing the elasticity and heat resistance of the resin, is added. Various investigations were conducted to determine this.

(B) Configuration of the Invention [Means for Solving the Problems] The present invention uses a specific inorganic substance, that is, an inorganic substance derived from a sol, so that a rubber-like polymer can be used in an amount of 0.1 to 30 μm.
Found that it can be made into non-sticky fine particles with a particle size of
And the particles are epoxy resin, methacrylic resin, 2-
The inventors have found that the toughness can be improved or the internal stress can be alleviated or the internal stress can be reduced without substantially lowering the elasticity and heat resistance of a cyanoacrylate resin, a polyphenylene sulfide resin, a phenol resin, a polyimide resin, a liquid crystal polymer, or the like.

That is, the present invention is a polymer powder having a particle diameter of 30 μm or less in which an inorganic material derived from an inorganic sol is supported on the surface of a rubber-like polymer powder.

Based on the organic polymer powder of the present invention, or fine particles of an organic polymer which is different from the matrix resin and can impart solvent resistance, heat resistance or weather resistance due to a film-like inorganic substance present on the surface. It provides internal stress relaxation, easy dispersibility due to a decrease in specific gravity, or low cost.

O Rubber-like polymer Specific examples of the rubber-like polymer in the present invention include acrylic rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, styrene-isoprene rubber, terpolymer rubber of ethylene-propylene-diene, and silicone rubber. Or an emulsion or latex such as ethylene-vinyl acetate rubber (hereinafter collectively referred to as an emulsion). Further, those obtained by adding silicone oil, castor oil, epoxidized soybean oil, or the like which is fluid at room temperature to these rubber components to lower Tg or increase the crosslinked state can also be used.

Of these rubber emulsions, preferred are acrylic rubbers which are less thermally degradable or deteriorate with time, and more preferred are acrylic crosslinked with allyl acrylate, allyl methacrylate, vinyl acrylate or vinyl methacrylate. It is rubber.

In the present invention, a so-called core shell having a rubbery polymer component as a core and having a resin having a high glass transition temperature on the outer wall, obtained by forming a polymer having a glass transition point of 50 to 200 ° C. in the presence of a rubber emulsion. It is preferred for the present invention to use an emulsion of a rubbery polymer of the type.

In order to form an emulsion of such a core shell type rubbery polymer, a vinyl monomer containing styrene, acrylonitrile, methacrylonitrile, methyl methacrylate, etc. as a main component is crosslinked in the presence of a rubber emulsion. Radical polymerization may be performed in the presence or absence of a methacrylic acid ester having an acidic functional group or the like, whereby a core-shell type rubbery polymer can be easily obtained.

In this case, the core rubbery polymer component is 30% by weight.
It is preferable that it is above.

As a combination of monomers that form a polymer having a glass transition point of 50 to 200 ° C., that is, a polymer of a shell portion,
40% by weight or more of at least one monomer selected from styrene, acrylonitrile, methacrylonitrile and methyl methacrylate, and 0.1 to 30% by weight of an alkoxysilane or titanate having an acryloxy group, a methacryloxy group or a vinyloxy group, and the balance. Is an alkyl acrylate, alkyl methacrylate, monoester or diester of maleic acid or fumaric acid, α-alkylstyrene, styrene substituted with a benzene nucleus, or a hydroxyl group, an amino group, a carboxyl group further derived from these monomers. Preferred is a known vinyl monomer having another functional group such as a group, a glycidyl group or an allyl group.

The use of a core-shell type organic polymer emulsion having a shell portion of a polymer having an alkoxysilane having an acryloxy group, a methacryloxy group or a vinyloxy group as a copolymer component is achieved by coating a silica or alumina coating with polymer particles. This is preferable in order to obtain inorganic microcapsules formed on the surface of.

Specific examples of the alkoxysilane having an acryloxy group, a methacryloxy group or a vinyloxy group include γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyl Tris (trimethylsiloxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrismethoxyethoxysilane or vinyltrichlorosilane
Specific examples of the titanate compound include isopropyl diacrylisostearoyl titanate and isopropyl dimethacrylisostearoyl titanate.

Particularly preferred as a core rubber emulsion for forming a coreier type rubber emulsion is an acrylate or methacrylate having a hydroxyl group, an amino group, a carboxyl group or a glycidyl group of 0.1 to 10% by weight, or further allyl group. Acrylates having an alkyl group having 2 to 8 carbon atoms by using together 0.1 to 2% by weight of an acrylate or methacrylate having a methallyl group or a vinyl group;
It is a rubber emulsion obtained by emulsion polymerization of about 88% by weight, and has a great effect of imparting impact resistance or internal stress relaxation to a fragile resin when used in a small amount.

As the surfactant used for forming the emulsion, it is preferable to use an anionic surfactant, particularly a derivative of sodium sulfonate or sodium sulfate, thereby easily forming an organic polymer having a large molecular weight. Can be

The particle size of the rubber-like polymer powder in these rubber emulsions is preferably 30 μm to 0.1 μm, more preferably 10 μm to 10 μm, in relation to the particle size of the finally obtained polymer powder.
0.1 μ.

○ Inorganic sol The inorganic sol used in the production of the polymer powder of the present invention is a colloidal solution obtained by dispersing inorganic ultrafine particles in water, and specifically, a sol such as silica, alumina, titanium oxide or iron oxide. No. Preferred inorganic sol for the present invention is silica sol or alumina sol,
A colloidal solution in which ultrafine particles of anhydrous silicic acid are dispersed in water, and commercially produced silica sol or colloidal silica can be used as it is for the production of polymer powder. Alumina sol is a colloid solution of positively charged ultrafine alumina, which can also be used commercially.

The preferred particle size of these inorganic sols is from 1 to 100 μm, more preferably from 5 to 50 μm from the viewpoint of facilitating production of the polymer powder, and particularly preferably from 5 to 20 μm. Considering the characteristics when the polymer powder is added to the resin, the content of the alkali component in the inorganic sol is 1%.
% Or less is preferable.

Further, in the present invention, several kinds of inorganic sols can be used in combination.

O Supporting method As a preferable method for supporting the inorganic material derived from the inorganic sol of the present invention on the rubber-like polymer, a rubber emulsion and the inorganic sol are mixed by a usual method, and the mixed solution is spray-dried or salted out. This is a method of coagulation. The preferred ratio of the rubbery polymer component and the inorganic component in the polymer powder of the present invention in which the inorganic material is supported is 20 to 90% by weight of the rubbery polymer component, and 80 to 10% by weight of the inorganic component.
And more preferably 30 to 90% by weight of the rubbery polymer component and 70 to 10% by weight of the inorganic component.

○ Method for removing eluting ions The polymer powder obtained as described above has, on its surface, an alkali metal ion or a strong acid derived from a surfactant or a neutralizing agent used in the production of a rubbery polymer. Eluting ions such as counter anions may remain at about 3,000 ppm or more, and such a rubber-like polymer may hinder the improvement of the moisture resistance of the resin to be modified, and the presence of those ions may cause the resin and rubber In some cases, the affinity with the compound may be impaired, and by removing them, the stability of quality and more excellent effects can be exhibited.

The removal of the eluting ions is carried out, for example, by adding an acidic substance, preferably sulfuric acid, hydrochloric acid or oxalic acid, to the fine particle suspension and heating the mixture to a temperature of 50 to 90 ° C. at a pH of 2 to 3 while adding 1 to 3 to
If the stirring is continued for 3 hours, most of the other metal ions such as alkali metal ions or alkaline earth metal ions bound to the particles will be eliminated and will be dissolved in the suspension medium.

The suspension in which the ions have been dissolved is subjected to centrifugation or sedimentation under gravity to obtain a suspension having an increased content of the rubbery polymer.Pure water is added to the suspension, and after standing, the supernatant is removed. To remove ions from the rubbery polymer. By repeating such an operation several times, it is possible to obtain a desired polymer powder having a low content of elutable ions. Further, it is also possible to use an ion exchange resin instead of the pure water washing.

In the case of removing the anion ions, if necessary, a treatment for adding an alkaline substance, for example, an aqueous solution of caustic soda or caustic potash to an alkali salt is performed before the above treatment.

In the present invention, a desirable eluting ion content as a polymer powder is 1000 ppm in total of cations and anions.
In the case where a high degree of crack resistance or moisture resistance in accordance with corrosion is required as required for the sealant, the total content of cations and anions is more preferably 100 ppm or less. It is particularly desirable that the alkali metal content be 100 ppm or less and the chloride ion content be 30 ppm or less.

○ Surface modification method using silane coupling agent The polymer powder obtained as described above is porous and has an inorganic material on its surface, so it has a physical binding property to resin, but it has an organic property. There is an inadequate chemical bond strength,
The affinity between the resin and the rubbery polymer may be partially impaired, and in order to improve the performance of the polymer powder, it is effective to modify the surface supporting the inorganic substance with a silane coupling agent. is there.

The modification of the surface carrying the inorganic substance with the silane coupling agent means that the silane coupling agent is adsorbed or chemically bonded to the inorganic surface of the polymer powder to provide a functional group capable of chemically bonding with the resin on the surface. It is to be.

The surface modification method is, for example, specifically adding the silane coupling agent as it is to the fine particle suspension, sufficiently mixing the mixture under stirring, and heating the mixture to 50 to 95 ° C. 3
A method in which stirring is continued for a period of time can be cited, whereby the silane coupling agent is adsorbed on the porous inorganic substance present on the surface of the fine particle rubber, or a condensation reaction occurs in a subsequent drying step, and the inorganic substance, for example, silica Alternatively, it chemically bonds with alumina or the like, and bonds with the silane coupling agent and silica or alumina on the surface. In this way, a surface-modified polymer powder having on its surface a functional group capable of chemically bonding to a resin is obtained.

As the polymer powder for modifying the inorganic surface with a silane coupling agent, it is naturally preferable to use a powder in which the solute ions in the fine particle suspension are reduced.

The silane coupling agent has a hydrolyzable alkoxy group, a carboxy group or a fluor group in the silicon atom, and further has a functional group having good compatibility with the resin, preferably a vinyl group or a methacryloyloxy group as an organic functional group which reacts with the resin. Group, a glycidyl group, an amino group or a mercapto group.

Specific examples of such compounds include vinyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltriacetoxysilane, vinyltrichlorosilane, methacryloxymethyltrimethoxysilane,
Methacryloxypropylmethyldimethoxysilane, 3-
Examples include glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

These are used in an amount of 0.1 to 10% by weight, more preferably 0.5 to 5% by weight, based on silica or alumina present on the surface of the rubber particles. When the content is less than 0.1% by weight, the bonding strength between the polymer powder and the resin is not sufficiently increased, while
If the amount is more than 10% by weight, a silane coupling agent having an insufficient bonding force with the inorganic substance will be present in the system, which is not preferable.

-Usage method The polymer powder of the present invention is added to various resins to improve the toughness or internal stress relaxation, adhesion, surface durability or contamination of the resins. When the resin is in a liquid state, it may be simply added and stirred and mixed with a conventional stirrer.If the resin is in a solid state, it may be melted or brought into a liquid state by using a solvent. Then, they can be added and mixed in the same manner.

The polymer powder of the present invention has excellent characteristics that it is very easily mixed with a liquid resin, finely dispersed and does not easily settle.

[Action]

The polymer powder of the present invention can be easily dispersed in fine particles in other types of resin components, and has toughness or internal stress relaxation for fragile resins and surface durability for flexible resins. Alternatively, it can impart heat resistance, and is particularly effective for adhesive resins, and improves peel adhesion strength based on an increase in toughness without substantially reducing the elasticity, heat resistance, or moisture resistance of the adhesive resin. It has an excellent effect that it can be performed.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples.

 The evaluation of the polymer powder was performed as follows.

Measurement of shear adhesive strength A resin mixed with a predetermined amount of polymer powder is mixed with a 1.6 mm thick S
After forming a coating film of 0.2 mm thickness on the S steel plate, layering the same steel plate on it, curing it under predetermined conditions, cooling to 23 ° C.,
It was measured at a displacement speed of 10 mm / min.

Measurement of peel strength A resin mixed with a predetermined amount of polymer powder, a 0.2 mm thick coating film was formed on a 0.6 mm thick aluminum plate, the same aluminum plate was stacked on this, and cured under predetermined conditions Thereafter, the sample was cooled to 23 ° C. and measured at a displacement speed of 20 mm / min in a T-shape.

Measurement of crack resistance In accordance with JIS-C-2105 (1975), the test method for solvent-free liquid resin for electrical insulation, an inner diameter of 60 mm with a tapered inner surface
A spring washer No. 12S specified by JIS-B-1251 was placed at the center of a stainless steel dish having a depth of 18 mm, and a resin in which a predetermined amount of polymer powder was mixed was filled therein.

After curing this under the specified conditions, JIS-C-2105 (1
In the thermal cycle test specified in 979), the cycle stage at which cracks occurred was recorded.

Example 1 (1) Synthesis of Rubber Emulsion 2 Into a stainless steel autoclave were charged 1,000 cc of pure water, 10 gr of Gohsenol GM-14, 0.2 gr of potassium persulfate, 10 gr of acrylic acid, 190 gr of vinyl acetate and 300 gr of ethylene, and a propeller-type stirring blade. 50 ℃ while stirring at 400rpm
For 15 hours, and further 70 g of methyl acrylate, 20 gr of acrylonitrile and 10 g of vinyltrimethoxysilane.
gr was charged, and emulsion polymerization was further continued at 60 ° C. for 4 hours.

(2) Support of silica 400 gr of the emulsion (solid content concentration 35% by weight) obtained in (1) above and Snowtex 20 L [particle diameter 40 to 50 mμ,
100 g of a silica sol having a silicic acid content of 20% by weight, manufactured by Nissan Chemical Industry Co., Ltd.] was placed in a beaker and mixed with a propeller type stirring blade for 30 minutes. Then, the mixture was continuously added to a 3 beaker having aluminum sulfate 18 hydrate 1.6 g and pure water 1,500 cc over 10 minutes while stirring with a propeller type stirring blade, and further stirred at 80 ° C. for 2 hours. After placing, the supernatant was removed.

(3) Drying of polymer powder The polymer slurry obtained by the above method was heated using a small spray dryer “Palvis Mini Spray GA-31” (manufactured by Yamato Scientific Co., Ltd.) at an inlet temperature of 180 ° C. and an outlet of hot air. Temperature 8
By drying at 0 ° C, spray air pressure of 1.5 kg / cm ² (gauge) and slurry supply rate of 15 cc / min, ethylene-vinyl acetate rubber component 73.0 wt%, silica component 12.7 wt%, sodium content 1,500 ppm, aluminum Particle size of 2 to 15 μm, consisting of 250 ppm in amount, 1,100 ppm in amount of sulfate group and 14.3% by weight of other polymer components, and carrying silica in the form of a film on the surface.
Was obtained as a polymer powder.

(4) Evaluation of polymer powder Epicoat 828 [bisphenol A type epoxy resin;
100 parts by weight of epoxy equivalent 190, manufactured by Shell Chemical Co., Ltd.] and 40 parts by weight of versamide 125 [curing agent for polyamide-amine type epoxy resin, amine value 350, manufactured by Henkel Hakusui Co., Ltd.] The shear strength, peel strength and crack resistance of the composition obtained by adding 10 parts by weight, 20 parts by weight or 30 parts by weight of the polymer powder were measured.

The shear strength and peel strength were evaluated for a cured product obtained by curing at 130 ° C. for 2 hours, and the crack resistance was evaluated for a cured product obtained by curing at 120 ° C. for 2 hours. The results are as follows.

Example 2 In step (2) of Example 1, the emulsion was coagulated and settled together with a silica sol, 40 cc of sulfuric acid was added with stirring, and the mixture was stirred at 80 ° C. for 2 hours to obtain a slurry. Put into a mixing tank with an internal volume of 20 containing water,
Washing with stirring for 30 minutes was performed. After stopping stirring, let it stand for 1 hour,
The slurry was settled, the supernatant was removed by siphon, and the same operation was repeated three more times to obtain a slurry 15 having a pH of 5.5 and a solid content of 10% by weight.

The slurry was spray-dried in the same manner as in Example 1, and ethylene-vinyl acetate rubber component 73.1% by weight, silica component 12.5% by weight, sodium content 5ppm, aluminum content 5p
pm, sulfate amount 25ppm and other polymer components 14.4% by weight
Consisting of a particle system 3 which supports silica in the form of a film on the surface.
10 μm of polymer powder was obtained.

Next, the substance of the obtained polymer powder was measured in the same manner as in step (4) of Example 1. The results were as follows.

Example 3 (Synthesis of Rubber Emulsion) 2 In a stainless steel autoclave, 1,000 cc of pure water and Levenol WZ [26% by weight aqueous solution of sodium polyoxyethylene alkyl phenyl ether sulfate, manufactured by Kao Corporation]
19.2gr, potassium persulfate 0.15gr, tertiary dodecyl mercaptan 1.0gr, 2-hydroxyethyl acrylate 5.0g
r, 150 gr of acrylonitrile and 345 gr of butadiene are charged and stirred at 50 ° C. with a propeller type stirring blade (350 rpm).
For 15 hours. Further, 19.2 gr of Levenol WZ, 0.5 gr of potassium persulfate, 70 gr of methyl methacrylate, 20 gr of methacrylonitrile and 10 gr of vinyldimethylmethoxysilane were added, and emulsion polymerization was further continued at 60 ° C. for 4 hours.

(Production of polymer powder and evaluation thereof) Emulsion (solid content: 35
% By weight), and by supporting silica on the rubbery polymer in the same manner as in Example 1, butadiene-
Acrylonitrile rubber component 68.5% by weight, silica component 17.5
Thus, a polymer powder having a particle size of 1 to 6 μm, which was composed of 1% by weight and 14.0% by weight of other polymer components and supported on the surface of the film-form silica, was obtained. The results of evaluating the physical properties of the obtained polymer powder by the same method as in Example 1 are as follows.

Comparative Reference Example (Synthesis of rubber emulsion) 2 In a stainless steel autoclave, 1,000 cc of pure water, 19.2 gr of Levenol WZ, 0.25 gr of potassium persulfate, 1.0 gr of allyl methacrylate and 500 gr of n-butyl acrylate
While stirring with a propeller-type stirring blade (350 rpm), nitrogen gas was flowed at 0.1 / min into the space of the flask.
The reaction was performed at 0 ° C. for 3 hours. Furthermore, Levenol WZ19.2gr,
1.0 gr of potassium persulfate, 140 gr of styrene, 60 gr of acrylonitrile and 5 gr of γ-methacryloxypropyltrimethoxysilane were charged, and emulsion polymerization was further continued at 70 ° C. for 4 hours.

The obtained acrylic rubber emulsion (solid content concentration: 40% by weight) was subjected to a coagulation treatment and further dried to obtain an acrylic rubber powder not supporting inorganic substances, and its particle diameter was 1,000 to 3,000 μm. Was.

(C) Effects of the Invention The organic polymer powder of the present invention can be used for other types of resins without requiring a large amount of solvent or strong stirring power.
Easy dispersion makes it possible to produce a resin that is commercially superior in toughness or relieves internal stress.Especially for adhesive resin, it has excellent performance in both peel strength and shear strength. Since it can be easily provided, it greatly contributes to various industries.

 ──────────────────────────────────────────────────続 き Continuation of the front page (31) Priority claim number Japanese Patent Application No. 2-171191 (32) Priority date Hei 2 (1990) June 28 (33) Priority claim country Japan (JP)

Claims (1)

(57) [Claims] 1. A polymer powder having a particle diameter of 30 .mu.m or less, wherein an inorganic material derived from an inorganic sol is supported on the surface of a rubber-like polymer powder.