JPH10182841A - Composite, production thereof and moldings containing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide composite moldings which can be shaped by melting and which are excellent in rigidity, heat resistance and transparency and have a low water absorption, and a composite suitable for the production of the moldings. SOLUTION: This composite has such a structure that a colloidal silica having an average particle diameter of not larger than 50nm in the form of substantially primary particles adheres to the surfaces of polymer particles. The composite further contains at least one surface modifier selected from among silane, titanate, aluminum, fatty acid and phosphoric acid surface modifiers. The composite is produced by a process having a step of adding at least one surface modifier selected from among silane, titanate, aluminum, fatty acid and phosphoric acid surface modifiers to a liquid mixture of an aq. latex containing polymer particles obtained by the emulsion polymn. of a radical-polymerizable vinyl compd. and an aq. dispersion of a colloidal silica. Moldings contain this composite. Moldings are produced by melt-shaping the composite.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composite comprising silica fine particles and organic polymer particles and a molded article using the composite.

[0002]

2. Description of the Related Art In general, many organic polymers have low rigidity, hardness and heat resistance, but as one of the attempts to overcome such problems, complexing with an inorganic substance has been studied so far.

As a composite composition containing colloidal silica, for example, Japanese Patent Publication No. 41180/1992, Japanese Patent Publication No.
No.-48832, Japanese Patent Publication No. 5-40796, Japanese Unexamined Patent Publication No.
287217, JP-A-6-199917, JP-A-7
JP-A-26165 and JP-B-7-94620 disclose a coating composition comprising an aqueous emulsion of an acrylic polymer having an alkoxysilyl group or a hydroxyl group and colloidal silica. However, these paints are effective in modifying the surface properties of plastic molded articles, but cannot improve the rigidity, toughness, and heat resistance of the molded articles themselves.

Further, JP-A-3-223333, JP-A-3-231925, JP-A-4-270710, and JP-A-5-117338 each disclose a colloidal silica core and a polyorganosiloxane shell. And a thermoplastic resin containing a copolymer obtained by graft copolymerization of a vinyl monomer with the core / shell body. The methods disclosed in these publications are:
A siloxane is polymerized in an aqueous colloidal silica dispersion to prepare a silica core / silicone shell, and a vinyl monomer is emulsion-polymerized thereon to obtain a vinyl polymer graft core / shell. For this reason, unless a large amount of silicone component is added, a large amount of unnecessary solids (cullet) is generated in the polymerization system, and depending on the type of vinyl monomer, a stable emulsion is obtained such that the system solidifies during polymerization. There was a problem.
That is, compositional restrictions were great. Further, according to the invention, the colloidal silica can only take a morphology completely covered by the silicone rubber, and the effects expected by introducing the colloidal silica into the resin,
That is, improvement in rigidity and heat resistance of a molded product has not been achieved. Also, J.I. Mat. Sci. , Vol.
29, p. According to 4651 (1994), it is theoretically and experimentally required that a structure in which an inorganic filler is covered with a rubber component does not exhibit high rigidity.

Further, JP-A-6-322036 discloses that emulsion polymerization or suspension polymerization of a (meth) acrylate and a cross-linking monomer is performed, and when a predetermined degree of polymerization is reached, a pretreatment with a silane coupling agent is performed. A method for producing a silica-containing acrylic polymer composition characterized by adding silica fine particles is disclosed. However, in this method, in order to disperse the silica well,
In addition, it is essential to use a cross-linking monomer in order to add a cross-linking agent later and thermally cross-link, and it is necessary to disperse the powdery silica fine particles in water in advance and perform a silane coupling agent treatment. It has to be complicated. In addition, the dispersion state of the powdery silica fine particles in the acrylic polymer is at a level of the order of submicron or more, and a molded article having excellent transparency intended in the present invention has not been obtained.

Japanese Patent Publication Nos. 56-50881, 62-213839, 7-53727, and 7-53728 each disclose charged inorganic particles and, on the contrary, charged inorganic particles. Consisting of polymer particles
A composite dispersion having a structure in which inorganic particles are coated around polymer particles and a method for producing a powder are disclosed. These have been implemented for soft, sticky polymer particles, and to prevent the polymers from sticking before use, coat the surface with hard silica, so-called blocking resistance improvement. This is a disclosure of an agent, which is used for paints, adhesives, and toners for copying. In this method, particles having different charges are mixed, so that aggregation between different particles is extremely fast, and it is difficult to obtain a uniform composite. Further, the publication does not suggest or disclose a melt-shapeable composite at all, nor does it suggest or disclose a molded article having a substantially thick and excellent transparency. .

JP-A-4-175351, JP-A-4-4-2
JP-A-61433 and JP-A-7-88355 each disclose an organic polymer powder used for filling an epoxy resin adhesive, which is characterized in that an inorganic material derived from an inorganic sol such as colloidal silica is carried on the surface. ing.
The polymer used here is also soft and sticky. Further, since all emulsifiers at the time of emulsion polymerization are sulfonate-based emulsifiers, it is not possible to efficiently coat colloidal silica around polymer particles while maintaining the state of primary particles. In this publication, for example, a composite particle having a particle size of 0.5 to 10 μm is obtained by mixing colloidal silica having a particle size of 10 to 20 nm with a polymer emulsion so as to have a content of 10 to 95% by weight and then spray drying. ing. Since the method of obtaining the product by spray drying is adopted, the composition of the product is the same as the composition of the charge, but in this manufacturing method, the colloidal silica around the polymer particles keeps the state of the primary particles No coated composite particles are obtained, and composite particles in which silica aggregates derived from colloidal silica are supported on polymer particles are obtained.

Further, a large particle having a particle radius a is changed to a particle radius b.
F. is a theoretical formula for calculating the maximum number of coatings when coating with small particles of F. K. According to Hansen et al.'S formula, it was found that silica of 10 to 20 nm could not be coated on the particles of 0.5 to 10 μm in the state of primary particles.

[0009]

(Equation 2)

For example, Example 15 of JP-A-4-175351 discloses a composite of 0.5 to 4 μm in which 42.9% by weight of a silica component is supported using colloidal silica having an average particle diameter of 15 nm as a raw material. ing. As a result of calculation, the actual number of colloidal silica particles per polymer in the composite was 3.5 times or more the maximum number of coated particles represented by the above formula, and exceeded 1.

That is, it can be seen that this powder does not carry the inorganic sol of the order of nanometers in the form of primary particles, but carries the aggregate of the inorganic sol.

On the other hand, JP-A-5-209027 discloses that
After treating the surface of colloidal silica having dispersibility in an organic solvent or water with an alkoxysilane compound, replacing the dispersion medium with a radically polymerizable vinyl compound and polymerizing it, a composite having excellent transparency is obtained. Is disclosed. Further, JP-A-5-287213, Journal of the Textile Society of Japan, Vol. 49, p. 130 (1993) and P
olym. Adv. Tech. , Vol. 3, p. 91
(1992) discloses a colloid solution in which colloidal silica dispersed in an organic solvent is modified with a chain polymer compound, and a composite powder obtained by distilling off or centrifuging the solvent. However, these methods have high raw material costs and complicated processes, and thus are not suitable as industrial production methods. Further, the composite disclosed in JP-A-5-209027 is a composite having an interpenetrating network structure of an organic polymer and a silica-based network, and thus cannot be melt-shaped.

Further, a collection of polymer papers, Vol. 46, p.
21 (1989), and the same magazine, Vol. 44, p. 4
83 (1987), the same magazine, Vol. 44, p. 839
(1987) discloses composite particles obtained by aggregating an organic polymer latex and silica particles. However, the particle size used in those documents is 2
With silica particles as large as 40 to 1590 nm, a molded article with excellent transparency intended by the present invention cannot be obtained.

[0014]

That is, a composite molded article which can be melt-shaped and has excellent rigidity, heat resistance and transparency has not been obtained.

In view of such a situation, the present inventors first attached colloidal silica having an average particle diameter of 50 nm or less in the form of substantially primary particles around polymer particles of a radically polymerizable vinyl compound. The invention discloses a composite and a molded article containing the composite, characterized by being melt-shapeable, and proposes a composite molded article having excellent rigidity, heat resistance, and transparency. (PCT / JP96
/ 01127). However, the composite molded article obtained by this technique has insufficient water absorption properties.

An object of the present invention is to provide a composite molded article which can be melt-shaped, is excellent in rigidity, heat resistance, and transparency, and has a low water absorption, and a composite suitable for producing this molded article. Is to do.

[0017]

Means for Solving the Problems The present inventors have conducted intensive studies on the cause of the high water absorption of the composite containing colloidal silica, and found that the colloidal silica used had a very small particle diameter and a high surface absorption. Was found to be water-absorbing at a hydrophilic interface having an enormous area between the organic polymer resin matrix and the colloidal silica particles in the composite molded article. Then, they have found that by making the surface of colloidal silica hydrophobic with a surface modifier, the water absorption of the molded article can be reduced, and arrived at the present invention.

The gist of the present invention is a composite having a structure in which colloidal silica having an average particle diameter of 50 nm or less adheres around polymer particles in the form of substantially primary particles. System, aluminum system,
The composite contains at least one surface modifier selected from fatty acid-based and phosphoric acid-based.

The gist of the present invention is that a mixture of an aqueous latex containing polymer particles obtained by emulsion polymerization of a radically polymerizable vinyl compound and an aqueous dispersion of colloidal silica is mixed with a silane-based, titanate-based or aluminum-based liquid. A process for adding at least one surface modifier selected from the group consisting of a fatty acid-based compound and a phosphoric acid-based compound.

Further, the gist of the present invention resides in a molded article containing the composite and a method for producing a molded article obtained by melt-shaping the composite.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION As the colloidal silica used in the present invention, those having an average particle diameter of 50 nm or less are used, and various commercial products using water as a dispersion medium can be used. Even if colloidal silica having a particle size larger than this particle size is used, good transparency, high rigidity, and heat resistance as intended in the present invention cannot be simultaneously exhibited.

The colloidal silica used in the present invention is usually negatively charged, and this can be easily determined by measuring the ζ potential using a principle such as electrophoresis.

The polymer particles have an average particle diameter of 20 to
2,000 nm, particularly preferably about 30 to 300 nm, is used. The charging state is not particularly limited, but a negatively charged state is preferable. As the type of polymer, polymers of radically polymerizable vinyl compounds, various engineering plastics such as polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, epoxy resin, reactive polyester resin, melamine resin, phenol resin, Thermosetting resins such as polyallyl resin and alkyd resin are exemplified. Of these, when using thermosetting polymer particles,
Although it cannot be melt-shaped by itself, it can be shaped by mixing it with a thermoplastic resin as described later.

Typically, polymer particles obtained by aqueous emulsion polymerization of a radically polymerizable vinyl compound are used. As the radical polymerizable vinyl compound, a known radical polymerizable monomer is used. Such compounds include, for example,
Methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate; acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; acrylic acid;
Α, β-unsaturated carboxylic acids such as methacrylic acid, maleic acid and itaconic acid; unsaturated carboxylic anhydrides such as maleic anhydride and itaconic anhydride; N-phenylmaleimide;
Maleimide derivatives such as -cyclohexylmaleimide and N-butylmaleimide; vinyl monomers containing a hydroxy group such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; acrylamide, methacrylamide , Acrylonitrile, methacrylonitrile, diacetone acrylamide, nitrogen-containing vinyl monomers such as dimethylaminoethyl methacrylate; allyl glycidyl ether, glycidyl acrylate, epoxy group-containing vinyl monomers such as glycidyl methacrylate; styrene, α-methylstyrene, etc. Styrene-based monomers; olefin-based monomers such as ethylene, propylene, butadiene, and 4-methyl-1-pentene; vinyl chloride and vinylidene chloride Halogen-containing vinyl monomer and the like;
Examples include crosslinkable monomers such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, allyl acrylate, allyl methacrylate, divinylbenzene, and trimethylolpropane triacrylate.
These radically polymerizable vinyl compounds can be used alone or
Used in combination of more than one species.

When a molded article is required to have high transparency, an alkoxysilane compound having a mercapto group or an ethylenically unsaturated group as a radically polymerizable vinyl compound is simultaneously present in the resulting polymer particles. It is preferable to use one containing at least one selected from an alkoxysilyl group and a silanol group.

Examples of the alkoxysilane compound include those represented by the following general formulas (I) to (VI).

[0027]

Embedded image

In the formula, R ¹ is a hydrocarbon group having 1 to 10 carbon atoms, R ² is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms which may contain an ether bond, and R ³ is a hydrogen atom or methyl. A group, n represents an integer of 0 to 2, p represents an integer of 1 to 10, and q represents an integer of 0 to 10.

As specific examples of the above compounds, examples of the alkoxysilane compound represented by the general formula (I) include γ-mercaptopropyltrimethoxysilane and γ
-Mercaptopropylmethyldimethoxysilane and the like.

Examples of the alkoxysilane compound represented by the general formula (II) include γ-acryloyloxypropyltrimethoxysilane, γ-acryloyloxypropyltriethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, and γ-acryloyloxypropylmethyldimethoxysilane. Acryloyloxypropylmethyldiethoxysilane, γ-acryloyloxypropylethyldimethoxysilane, β-acryloyloxyethyltrimethoxysilane, β-acryloyloxyethylmethyldimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane Ethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane,
γ-methacryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylethyldimethoxysilane, γ-methacryloyloxypropyldimethylmethoxysilane, β-methacryloyloxyethyltrimethoxysilane, β-methacryloyloxyethylmethyldimethoxysilane and the like.

As the alkoxysilane compound represented by the general formula (III), for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-butoxysilane, vinyltris (β-methoxyethoxy) silane, vinylmethyldimethoxysilane , Vinylmethyldiethoxysilane, vinylethyltrimethoxysilane, vinyldimethylmethoxysilane, isopropenyltrimethoxysilane, isopropenylmethyldimethoxysilane,
Allyltrimethoxysilane, 5-hexenyltrimethoxysilane, 9-decenyltrimethoxysilane and the like can be mentioned.

Examples of the silane compound represented by the general formula (IV) include p-vinylphenyltrimethoxysilane (also known as p-trimethoxysilylstyrene), p-vinylphenyltriethoxysilane, and p-vinylphenyltriisosilane. Propoxysilane, p-vinylphenylmethyldimethoxysilane, p-vinylphenylmethyldiethoxysilane, p-vinylphenylethyldimethoxysilane, p
-Vinylphenylpropyldimethoxysilane, p-vinylphenylphenyldimethoxysilane, p-vinylphenyldimethylmethoxysilane, o-vinylphenyltrimethoxysilane, o-vinylphenylmethyldimethoxysilane, m-vinylphenyltrimethoxysilane, o-
Examples include vinylphenylmethyldimethoxysilane, p-isopropenylphenyltrimethoxysilane, p-isopropenylphenylmethylmethoxysilane, m-isopropenylphenyltrimethoxysilane, and m-isopropenylphenylmethyldimethoxysilane.

Examples of the silane compound represented by the general formula (V) include trimethoxysilylpropyl vinyl ether, methyldimethoxysilylpropyl vinyl ether and the like. Examples of the silane compound represented by the general formula (VI) include vinyl 11-trimethoxysilylundecanoate.

Of these, those represented by the general formulas (I), (II) and (III) are preferably used in the present invention in view of availability and price, and particularly preferably used. Examples thereof include γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, and vinyltrimethoxysilane.

However, when an alkoxysilane compound having an ethylenically unsaturated group is blended in a large amount, crosslinking occurs at many sites between molecules due to condensation of silanol groups. Melt fluidity may be reduced to form a gel, and the shapeability may deteriorate. For this reason, the silane compound most preferably used in the present invention is an alkoxysilane compound having a mercapto group.

The compounds represented by these general formulas (I) to (VI)
The alkoxysilane compounds having a mercapto group or an ethylenically unsaturated group are used alone or in combination of two or more.

When an alkoxysilane compound having a mercapto group is used, the amount is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, based on 100 parts by weight of the above-mentioned radically polymerizable vinyl compound. It is particularly preferred that there is.

When an alkoxysilane compound having an ethylenically unsaturated group is used, it is not preferable in the present invention to use an excessively large amount for the above-mentioned reason.
The compounding amount is preferably 1 part by weight or less based on 100 parts by weight of the radical polymerizable vinyl compound.
It is particularly preferred that the amount is 5 parts by weight or less.

Formulas (I) to (VI):
When an alkoxysilane compound having a mercapto group or an ethylenically unsaturated group is used together with a radically polymerizable vinyl compound, there is an advantage that the colloidal silica and the polymer particles of the radically polymerizable vinyl compound can be more uniformly compounded.

The composite of the present invention further contains at least one type of surface modifier selected from silanes, titanates, aluminums, fatty acids, and phosphoric acids. These surface modifiers are compounds having a group having an affinity for an organic resin matrix and a group having an affinity for an inorganic substance, and modify the surface of colloidal silica by blending.
Organophilic, that is, hydrophobic. This suppresses water absorption at the interface between the organic polymer resin matrix and colloidal silica, and contributes to a reduction in the water absorption of the composite molded article. Further, the surface modification of the colloidal silica has a function of improving the dispersibility of the colloidal silica in the resin matrix, and contributes to the improvement of the transparency and impact resistance of the molded product.

As such a silane-based surface modifier, alkoxysilane compounds represented by the above-mentioned general formulas (I) to (VI) can be used. Also, methyltrichlorosilane,
Dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ -Glycidoxypropyldimethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3
4-epoxycyclohexyl) ethylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, and polydimethylsiloxanes having a silanol group or an alkoxysilyl group.

Examples of titanate-based surface modifiers include Plenact KR-TTS commercially available from Ajinomoto Co., Inc.
KR-46B, KR-55, KR-41B, KR-38
S, KR-138S, KR-238S, 338X, KR
-12, KR-44, KR-9SA, KR-34S, K
R-ET, titacoat S-151, S-152, S-152P, S-18 commercially available from Nippon Soda Co., Ltd.
1, S-581, S-582, P-151P, R-16
1, R-291, C-151, C-231, PR-58
1, W-585, W-184, W-586, W-292
And the like.

Examples of the aluminum-based surface modifier include acetoalkoxyaluminum diisopropylate. Examples of the fatty acid-based surface modifier include carboxylic compounds containing a long-chain alkyl group such as stearic acid, N-lauroyl lysine, N-lauryl aspartic acid-β-lauryl ester, N-lauryl aspartic acid-β-stearyl ester and the like. Is mentioned.

Examples of the phosphoric acid-based surface modifier include alkyl acidic phosphoric acid esters. Among the above-described titanate-based surface modifiers, many having a phosphate group are known, and these are also mentioned as the surface modifier used in the present invention.

The step of emulsion polymerization of a radically polymerizable vinyl compound in an aqueous system to obtain an aqueous latex of polymer particles is performed in the following manner.

Examples of the radical polymerization initiator include an oxidizing agent comprising an organic hydroperoxide such as tertiary butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, a sugar-containing iron pyrophosphate formulation, Xylate prescription,
Redox initiators in combination with reducing agents such as a mixture of sugar-containing iron pyrophosphate formulation / sulfoxylate formulation; persulfates such as potassium persulfate and ammonium persulfate; azobisisobutyronitrile, azobisdimethyl Azo compounds such as valeronitrile and dimethyl-2,2'-azobisisobutyrate; organic peroxides such as benzoyl peroxide and lauroyl peroxide; and the like, preferably redox initiators . The amount of the radical polymerization initiator used is usually, based on 100 parts by weight of the radically polymerizable vinyl compound,
It is about 0.01 to 5 parts by weight.

As the emulsifier, known emulsifiers can be used, for example, sodium dodecylbenzenesulfonate,
Sulfonate emulsifiers such as sodium lauryl sulfate, sodium diphenyl ether disulfonate, sodium dialkyl sulfosuccinate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium salt of polyoxyethylene alkyl ether phosphate and sodium salt of polyoxyethylene alkyl phenyl ether phosphate Phosphate emulsifiers such as potassium oleate, sodium N-lauroyl sarcosinate, N-
Carboxylate emulsifiers such as sodium myristoyl sarcosinate and potassium alkenyl succinate, or at least one nonionic emulsifier such as polyoxyethylene alkyl ester and polyoxyethylene alkyl aryl ether are preferably used. These are phosphate emulsifiers and carboxylate emulsifiers, and more preferably used are phosphate emulsifiers.

The term "phosphate emulsifier" used herein means:
It also includes a phosphoric acid emulsifier represented by polyoxyethylene alkyl ether phosphate and polyoxyethylene alkyl allyl ether phosphate. Further, a polymer having a surfactant activity which partially contains a phosphate group is also used as a polymerization emulsifier, and is therefore included in the phosphate emulsifier according to the present invention. The use of a phosphate emulsifier has the advantage that when colloidal silica is added to an emulsion polymerization latex of a radically polymerizable vinyl compound, it can be most efficiently introduced into the composite of the present invention.

The amount of the emulsifier used is usually 0.5 to 10 parts by weight per 100 parts by weight of the radically polymerizable vinyl compound.
It may be about parts by weight.

In the present invention, a chain transfer agent can be used if necessary. Specific examples of the chain transfer agent include, for example, mercaptans such as tertiary dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, n-hexyl mercaptan; carbon tetrachloride,
Examples thereof include halogen compounds such as ethylene bromide, which are usually used in an amount of 1 part by weight or less based on 100 parts by weight of the radically polymerizable vinyl compound.

At the time of emulsion polymerization, if necessary, various electrolytes, pH adjusters and the like are used in combination, and the polymerization temperature is 5 to 5.
100 ° C, preferably 40 to 95 ° C, polymerization time 0.1 to
This is performed under conditions of about 24 hours.

In the emulsion polymerization step, the method of adding the radically polymerizable vinyl compound to the reactor may be batch, divided or continuous addition, or a combination thereof.

By such a process, an aqueous latex of polymer particles of the radically polymerizable vinyl compound is obtained.

In the present invention, it is preferable to use an aqueous latex of negatively charged polymer particles. That is, since colloidal silica is usually negatively charged, when mixed with an aqueous dispersion of colloidal silica using an aqueous latex of positively charged polymer particles, non-uniform aggregation occurs due to strong electrical attraction of both. And as a result,
It becomes difficult to obtain a composite having a structure in which the colloidal silica is uniformly attached to the polymer particles while maintaining the state of the primary particles.

The blending amount of colloidal silica and polymer particles is not particularly limited, and is selected according to the required performance.
Preferably from 1 to 500 parts by weight, particularly preferably from 1 to 15 parts by weight
Use 0 parts by weight. In particular, when the composite obtained in the present invention is melt-formed alone, the amount of colloidal silica is preferably 1 to 150 parts by weight based on 100 parts by weight of the polymer. Above all, when only the composite of the present invention is pelletized by a kneading machine such as an extruder, and then melt-shaped by a known method such as injection molding, the composite is extruded into a pellet and melt-flowable by injection molding. Must have the property. At this time, the amount of colloidal silica is preferably 1 to 100 parts by weight based on 100 parts by weight of the polymer. However, this does not apply when other known polymers are appropriately blended with the composite of the present invention to form a thermoplastic resin composition.

However, the most preferable blending amount of the colloidal silica and the polymer is to select an amount within a range where the colloidal silica particles can adhere around the polymer particles while maintaining the state of the primary particles. It is. That is, when coating large particles (polymer particles) having a particle radius a with small particles (colloidal silica) having a particle radius b, F.F. K. It is necessary to set the amount according to the maximum number of coated particles calculated by the formula of Hansen et al. As the upper limit of the blending amount of colloidal silica.

That is, it is necessary that the average number N of colloidal silica particles adhered per polymer particle is within the range represented by the following formula.

[0058]

(Equation 3)

When an amount of colloidal silica exceeding this range is blended, the colloidal silica can no longer adhere around the polymer particles in the form of primary particles, and aggregates of the silica particles form around the polymer particles. Will adhere.
Since it is impossible to disperse the silica again in the state of primary particles if the silica is aggregated, the purpose was to obtain a molded article having excellent transparency by dispersing the colloidal silica in the state of the primary particles. This is not preferred in the present invention.

For example, when polymer particles having a particle diameter of 50 nm and colloidal silica having a particle diameter of 15 nm are used, the maximum number of coated particles is 68. The blending amount of the polymer and the colloidal silica when the maximum number of coated particles is obtained is 23% by weight of the polymer.
If the amount of silica is less than this value, the silica is uniformly attached in the form of primary particles around the polymer particles, but if it is more than this value, the silica aggregates. Means adhered around the polymer particles.

Similarly, when polymer particles having a particle diameter of 100 nm and colloidal silica having a particle diameter of 15 nm are used,
The maximum number of coated particles is 213. The blending amount of the polymer and colloidal silica at the time of obtaining the maximum coating number particles is as follows.
% By weight and 56% by weight of silica. If the amount of silica is less than this value, the silica is uniformly attached in the form of primary particles around the polymer particles. It means that it is aggregated and attached around the polymer particles.

In particular, after the composite obtained by the present invention is pelletized by a kneading machine such as an extruder, only the composite of the present invention is melt-shaped by a known method such as injection molding, or a solvent or monomer. In the case of dissolving in colloidal silica, the average particle number N of the colloidal silica (average particle radius b) adhered per polymer particle (average particle radius a) falls within the range represented by the following formula. Determining the compounding amount is most preferable in consideration of melt shapeability (flowability of the resin at the time of melting, etc.) and solubility in a solvent or a monomer.

[0063]

(Equation 4)

If colloidal silica is blended out of this range, the melt fluidity and solubility of the resin will be reduced, and only the composite of the present invention may be pelletized by a kneading machine such as an extruder or injection-molded. Can be difficult.

However, this does not apply when other known polymers are appropriately blended with the composite of the present invention to form a thermoplastic resin composition.

In the present invention, a silane type, a titanate type,
The amount of at least one type of surface modifier selected from the group consisting of aluminum, fatty acid, and phosphoric acid is selected according to the required performance, and is usually 0.1 to 100 parts by weight of colloidal silica. ~ 50 parts by weight, preferably 0.5 ~
20 parts by weight, particularly preferably 0.5 to 10 parts by weight, is used. If the amount is less than this range, there is no effect in reducing the water absorption of the composite, and if it is too large, the water absorption of the composite is reduced, but strength, rigidity, and other physical properties such as heat resistance may be reduced. .

As a method for obtaining the composite of the present invention, an aqueous dispersion of colloidal silica and at least one surface modification selected from silanes, titanates, aluminums, fatty acids and phosphoric acids are added to the obtained aqueous latex. What is necessary is just to add a filler, and to stir at room temperature-100 degreeC for arbitrary time.

An aqueous dispersion (mixed liquid) of the composite of the present invention is obtained by the above stirring. When water is separated from the mixed liquid, the composite is obtained.

As a method for separating water from the mixed solution,
Known methods, that is, a coagulation method such as a salt coagulation method and an acid coagulation method, and a spray drying method (spray drying method) are exemplified.

As a specific example of the coagulation method, a mixed solution of the resulting complex is added to an aqueous solution of a salt such as calcium chloride, magnesium chloride, magnesium sulfate, aluminum sulfate, or calcium acetate, or an acid such as sulfuric acid. It is obtained by heating and coagulating as necessary. The obtained powdery product is purified by washing with water and drying.

In place of the salt or acid aqueous solution, the resulting mixed solution is dissolved in a water-soluble solvent such as methanol, ethanol, or isopropyl alcohol which does not dissolve the polymer of the radically polymerizable vinyl compound. Solidification is also possible by adding and heating.

In the spray drying method (spray drying method), a powdery composite can be obtained by spraying a mixed solution in a heated atmosphere.

The complex isolated above has an average particle size of 5
It has a structure in which colloidal silica of 0 nm or less adheres around polymer particles of a radically polymerizable vinyl compound. This can be confirmed by observation with a transmission electron microscope.

When a resin molded article is produced using this composite, the used colloidal silica is present in the molded article in the form of primary particles without agglomeration, and the particle diameter is small. Thus, a product having excellent transparency can be obtained. According to transmission electron microscope observation, it was found that the colloidal silica fine particles in the molded article were dispersed very uniformly, without agglomeration, in the form of primary particles, which proved that the molded article had good transparency. It is thought that it expresses sex.

The composite of the present invention is a thermoplastic composite that can be melt-shaped and can be pelletized by a kneading machine such as an extruder, injection molding, compression molding (press molding). It can be formed into a desired shape by a known method. At this time, only the composite of the present invention can be pelletized, or other known polymers are appropriately blended depending on the required performance, usually at about 99% by weight or less, preferably at about 90% by weight or less. , Can also be used as a thermoplastic resin composition.

As the polymer to be blended, for example,
Polyethylene, polypropylene, poly 4-methyl-1-
Pentene, polymethyl methacrylate, polymethyl methacrylate copolymer (acrylic resin), methyl methacrylate-styrene copolymer, polystyrene, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, styrene-maleimide copolymer Coal, rubber-modified styrene-maleimide copolymer, rubber-reinforced polystyrene (HIPS), acrylonitrile-butadiene-styrene resin (ABS resin), acrylonitrile-ethylenepropylene-styrene resin (AES resin), methyl methacrylate-butadiene-styrene resin ( MBS resin), acrylonitrile-butadiene-methyl methacrylate, styrene resin, acrylonitrile-n-butyl acrylate-styrene resin (AAS resin), polyvinyl chloride, polyvinyl chloride Lidene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, epoxy resin, polyvinylidene fluoride, polysulfone, ethylene-vinyl acetate copolymer, PPS resin, polyetheretherketone, PPO resin, rubber-modified PPO resin, polyamide Elastomer, polyester elastomer, polybutadiene, butadiene-styrene copolymer, acrylonitrile-butadiene copolymer, polyisoprene, natural rubber,
Acrylic rubber, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, chlorinated butyl rubber,
Examples include various thermoplastic polymers such as chlorinated polyethylene, styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, and hydrides of the block copolymer.

The pelletized thermoplastic resin (composition) is processed, molded, and spun by ordinary means such as compression molding (press molding), injection molding, and melt spinning.

The composite of the present invention can be dissolved or dispersed in various solvents, the above-mentioned thermoplastic resins, a solvent in which a polyacrylonitrile-based polymer, a cellulose-based polymer or the like is dissolved, and a vinyl monomer. Accordingly, the composite of the present invention is dissolved or dispersed in a solvent in which various solvents or polymers are dissolved, or in a vinyl monomer, and is subjected to bulk polymerization, suspension polymerization, or solution polymerization, wet and dry spinning to form a plate. It can also be shaped into rods, granules, films, fibrous products and the like.

Further, in any of the convenient steps in the present invention, additives such as a coloring agent, an ultraviolet absorber, a heat and / or light stabilizer, and a release agent are mixed within a range not to impair the effects of the present invention. Can be used.

[0080]

The present invention will be described below in detail with reference to examples. In the examples, “parts” means “parts by weight” unless otherwise specified. The evaluation methods for physical properties and the like are as follows.

1) Transparency was measured using a haze meter (manufactured by Suga Test Instruments Co., Ltd., HGM-2DP) according to ASTM.
The total light transmittance (total transmittance) and the haze value were measured using a 1/8 inch thick sample according to D1003. 2) The water absorption was determined from the weight change rate when immersed in boiling water for 8 hours based on the weight of a 5 cm square plate sample (1/8 inch thick) after vacuum drying at 80 ° C. for 48 hours. . 3) The linear expansion coefficient is SSC manufactured by Seiko Electronic Industry Co., Ltd.
It measured by the TMA method using -5000. 4) For the strength, a bending test was performed according to ASTM D790, and the bending strength and the flexural modulus were measured. 5) The inorganic content in the composite was calculated from the residue when a predetermined amount of the sample was ignited in a crucible. 6) The average particle diameter and the ζ potential of the polymer particles and the ζ potential of the colloidal silica were measured using a dynamic light scattering / laser Doppler electrophoresis apparatus (ELS-800, manufactured by Otsuka Electronics Co., Ltd.).

Example 1 Deionized water was placed in a separable flask equipped with a condenser, a nitrogen inlet, and a stirrer.
00 parts, polyoxyethylene alkylphenyl ether phosphate sodium salt (GAFAC LO-529, manufactured by Toho Chemical Industry Co., Ltd.) as an emulsifier
25 parts, sodium ethylenediaminetetraacetate 0.000
3 parts, 0.2 part of sodium formaldehyde sulfoxylate and 0.0001 part of ferrous sulfate were added, and the temperature was raised to 75 ° C. while stirring. Thereto, a mixture of 90 parts of methyl methacrylate, 10 parts of methyl acrylate, 0.5 part of γ-mercaptopropyltrimethoxysilane, and 0.125 part of tert-butyl hydroperoxide was dropped over 3 hours. After completion of the dropwise addition, the temperature is maintained at 75 ° C. for 1 hour.
An aqueous latex of polymer particles was obtained. The average particle diameter of the polymer particles by dynamic light scattering (DLS) is 90 nm.
And the ζ potential was -28 mV, and the particles were negatively charged.

Next, an aqueous colloidal silica dispersion having an average particle diameter of 15 nm and a ζ potential of −17 mV (silica content: 20% by weight, manufactured by Nissan Chemical Industries, Ltd .;
125 parts (silica content: 25 parts) were added with stirring, 0.25 parts of dimethyldimethoxysilane was added, and the mixture was kept at 75 ° C. for 1 hour. DL after this step
According to the S measurement, the average particle size was 105 nm, and an increase in the particle size was observed.

Note that F.S. K. The particle size of a small particle having a particle size of 15 nm, 90 nm, calculated by the formula of Hansen et al.
Was 178, and the average number N of colloidal silica particles per polymer in the blending amount of this example was 29.

According to a transmission electron micrograph of this composite, it was observed that colloidal silica having a particle diameter of 15 nm adhered in the form of primary particles around the methyl methacrylate-methyl acrylate copolymer particles.

After cooling the reaction system, the content was poured into 500 parts of warm water in which 5 parts of calcium acetate were dissolved, and subjected to salting out and coagulation to separate a powdery composite. Thereafter, the powdery composite was thoroughly washed with water and dried at 90 ° C. for 24 hours. The recovery of this powdery composite was 97%, the inorganic content in the composite was 21% by weight, and the added colloidal silica was quantitatively introduced into the composite.

This powdery composite was extruded at a cylinder temperature of 220 ° C. using a twin-screw extruder.
A pellet was obtained. Table 1 shows the physical properties of the molded products obtained by injection molding of the above pellets.

According to a transmission electron micrograph of a sample obtained by press-molding the above pellet at a mold temperature of 220 ° C.,
It was observed that the colloidal silica particles having a primary particle diameter of 15 nm were uniformly dispersed without agglomeration.

Examples 2 to 9 Composites, pellets and molded articles were obtained in the same manner as in Example 1 except that the surface modifiers shown in Table 1 were used instead of dimethyldimethoxysilane. The recovery of the composite was 97%, the inorganic content in the composite was 21% by weight, and the added colloidal silica was quantitatively introduced into the composite.

Comparative Example 1 A composite, a pellet and a molded product were obtained in the same manner as in Example 1 except that dimethyldimethoxysilane was not used. The recovery of the composite was 97%, the inorganic content in the composite was 21% by weight, and the added colloidal silica was quantitatively introduced into the composite.

(Example 10) The amount of the aqueous colloidal silica dispersion S-1 was 214 parts (a silica content of 43 parts).
A composite, a pellet, and a molded product were obtained in the same manner as in Example 1, except that the amount of dimethyldimethoxysilane added was 2.15 parts. The recovery of the composite was 98%, the inorganic content in the composite was 31% by weight, and the added colloidal silica was quantitatively introduced into the composite. N is 5
It was 0.

Comparative Example 2 A composite, a pellet and a molded product were obtained in the same manner as in Example 10 except that dimethyldimethoxysilane was not used. 97% recovery of complex
The inorganic content in the composite was 31% by weight, and the added colloidal silica was quantitatively introduced into the composite.

(Example 11) When the average particle size was 25 nm
An aqueous dispersion of colloidal silica having a potential of −40 mV (silica content 20% by weight, manufactured by Nissan Chemical Industries, Ltd.) was used in 333 parts (silica content: 67 parts), and the amount of dimethyldimethoxysilane added was changed to 3.35 parts. In the same manner as in Example 1, a composite, a pellet, and a molded product were obtained. The recovery of the composite is 97%, and the inorganic content in the composite is 41% by weight.
And the added colloidal silica was quantitatively introduced into the polymer. R was 77 and N was 17.

(Example 12) When the average particle diameter was 45 nm
Colloidal silica aqueous dispersion having a potential of -40 mV (silica content 20% by weight, manufactured by Nissan Chemical Industries, Ltd .; hereinafter, S-2
(Hereinafter abbreviated as 100 parts) and the addition amount of dimethyldimethoxysilane was changed to 5 parts to obtain a composite, a pellet, and a molded article in the same manner as in Example 1. The recovery of the composite was 98%, the inorganic content in the composite was 50% by weight, and the added colloidal silica was quantitatively introduced into the polymer. R is 33 and N
Was 4.

(Example 13) The amount of the aqueous colloidal silica dispersion S-2 was changed to 750 parts (silica content: 150 parts).
A composite, a pellet, and a molded product were obtained in the same manner as in Example 1, except that the amount of dimethyldimethoxysilane added was 7.5 parts. The recovery of the composite was 98%, the inorganic content in the composite was 60% by weight, and the added colloidal silica was quantitatively introduced into the composite. N was 7.

50 parts of this powdery composite was mixed with 90% of methyl methacrylate component and 10% of methyl acrylate component.
% Of a copolymer bead consisting of 50% by weight and a cylinder temperature of 220 using a twin screw extruder.
Extruded at ℃ to obtain pellets. The above pellets were injection molded to obtain a molded product.

(Example 14) In a separable flask equipped with a condenser, a nitrogen inlet and a stirrer, 200 parts of deionized water and polyoxyethylene alkylphenyl ether phosphate sodium salt as an emulsifier (manufactured by Toho Chemical Industry Co., Ltd.) , Trade name: GAFAC LO-529)
1.25 parts, sodium ethylenediaminetetraacetate 0.0
003 parts, 0.2 parts of sodium formaldehyde sulfoxylate and 0.0001 parts of ferrous sulfate were added, and the temperature was raised to 75 ° C. while stirring. There, styrene 80 parts, α
A mixture of 20 parts of methylstyrene, 0.1 part of γ-mercaptopropyltrimethoxysilane, and 0.25 part of cumene hydroperoxide was added dropwise over 3 hours.
After completion of the dropwise addition, the mixture was kept at 75 ° C. for 1 hour, and then 0.2 parts of cumene hydroperoxide was added and kept at 75 ° C. for 1 hour to obtain an aqueous latex of polymer particles. The average particle size by DLS of the polymer particles was 90 nm, the ζ potential was −35 mV, and the particles were negatively charged.

Next, 214 parts of colloidal silica aqueous dispersion S-2 (43 parts of silica) was added thereto with stirring, and 2.15 parts of dimethyldimethoxysilane was added thereto, and the mixture was maintained at 75 ° C. for 1 hour. did. Thereafter, a composite, a pellet, and a molded product were obtained in the same manner as in Example 1. The composite recovery rate was 97%, and the inorganic content in the composite was 3%.
It was 0% by weight, and the added colloidal silica was quantitatively introduced into the polymer. R was 33 and N was 2. Although the molded product was opaque, the surface was smooth, the water absorption and the coefficient of linear expansion were small, the dimensional stability against temperature and humidity changes was excellent, and the molded product had good performance as a base material for an optical mirror.

According to a transmission electron micrograph of a sample obtained by press-molding the pellet at a mold temperature of 220 ° C.,
It was observed that the colloidal silica particles having a primary particle diameter of 45 nm were uniformly dispersed without agglomeration.

(Example 15) The amount of the aqueous colloidal silica dispersion S-2 was changed to 750 parts (silica content: 150 parts).
A composite, a pellet, and a molded product were obtained in the same manner as in Example 14, except that the amount of dimethyldimethoxysilane added was 7.5 parts. The recovery of the composite was 97%, the inorganic content in the composite was 60% by weight, and the added colloidal silica was quantitatively introduced into the composite. N was 6.

(Example 16) 50 parts of the powdery composite obtained in Example 15 was blended with 50 parts of polystyrene pellets (trade name: Styron 685, manufactured by Asahi Kasei Kogyo Co., Ltd.), and a twin screw extruder was used. Using the cylinder temperature 2
Extrusion was performed at 20 ° C. to obtain pellets. The pellet was injection molded to obtain a molded product. Although the molded product was opaque, the surface was smooth, the water absorption and the coefficient of linear expansion were small, the dimensional stability against temperature and humidity changes was excellent, and the molded product had good performance as a base material for an optical mirror.

Example 17 50 parts of the powdery composite obtained in Example 15 was mixed with 50 parts of polycarbonate powder (trade name: Iupilon S2000F, manufactured by Mitsubishi Gas Chemical Co., Ltd.).
And the mixture was extruded at a cylinder temperature of 260 ° C. using a twin-screw extruder to obtain pellets. The pellet was injection molded to obtain a molded product. Although the molded product was opaque, the surface was smooth, the water absorption and the coefficient of linear expansion were small, the dimensional stability against temperature and humidity changes was excellent, and the molded product had good performance as a base material for an optical mirror.

[0103]

[Table 1]

The abbreviations in Table 1 are as follows. DMDMS: dimethyldimethoxysilane GPTMS: γ-glycidoxypropyltrimethoxysilane MPTMS: γ-methacryloyloxypropyltrimethoxysilane CPTMS: γ-chloropropyltrimethoxysilane VTMS: vinyltrimethoxysilane MTMS: methyltrimethoxysilane PTMS: phenyl Trimethoxysilane KR41B: Tetraisopropyl bis (dioctyl phosphite) titanate (manufactured by Ajinomoto Co., Ltd., trade name: Prenact KR-41B) P-18: Alkyl acid phosphate ester (manufactured by Ajinomoto Co., trade name: Famex) P-18)

[0105]

The composite of the present invention can be melt-shaped and can provide a molded article having excellent rigidity, heat resistance and transparency and low water absorption. Further, the molded article of the present invention can be used in various fields such as window glass for houses and vehicles, various optical materials such as lenses and reflectors, and inorganic-filled high-hardness materials represented by dental materials.

Claims (13)

[Claims] 1. A composite having a structure in which colloidal silica having an average particle diameter of 50 nm or less adheres around polymer particles in a substantially primary particle state, and further includes a silane-based, titanate-based, and aluminum-based And a complex containing at least one surface modifier selected from fatty acids and phosphoric acids. 2. The composite according to claim 1, wherein the composite has a structure in which negatively charged colloidal silica is attached around negatively charged polymer particles. 3. An average particle number N of colloidal silica (average particle radius b) adhered per polymer particle (average particle radius a) is in a range represented by the following formula. The conjugate of claim 1. (Equation 1) 4. The composite according to claim 1, wherein the polymer particles are obtained by emulsion polymerization using a phosphate emulsifier. 5. The composite according to claim 1, wherein the polymer particles are obtained by emulsion polymerization using a carboxylate emulsifier. 6. The composite according to claim 1, wherein the polymer particles have at least one selected from an alkoxysilyl group and a silanol group. 7. A polymer particle containing at least one selected from an alkoxysilyl group and a silanol group is obtained by emulsion-polymerizing a mixture of an alkoxysilane compound having a mercapto group and a radically polymerizable vinyl compound in an aqueous system. The composite according to claim 6, wherein: 8. A polymer particle containing at least one selected from an alkoxysilyl group and a silanol group, obtained by emulsion-polymerizing a mixture of an alkoxysilane compound having an ethylenically unsaturated group and a radically polymerizable vinyl compound in an aqueous system. 7. The composite according to claim 6, wherein 9. A molded article containing the composite according to claim 1. 10. The molded article according to claim 9, having a substantial thickness. 11. The molded article according to claim 10, wherein the colloidal silica is substantially dispersed in a state of primary particles. 12. A mixture of an aqueous latex containing polymer particles obtained by emulsion polymerization of a radically polymerizable vinyl compound and an aqueous dispersion of colloidal silica, is mixed with a silane, titanate, aluminum, fatty acid, phosphorus, The method for producing a composite according to claim 1, further comprising a step of adding at least one type of a surface modifier selected from an acid type. 13. A method for producing a molded article obtained by melt-shaping the composite according to claim 1.