JP2661979B2 - Polymerizable composition for molding containing fine polymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel polymerizable composition for molding. More specifically, for example, in reaction injection molding (RIM) and the like, there is little radical heat generation during polymerization (curing) reaction,
The present invention also relates to a novel polymerizable composition for molding having improved characteristics such as molding shrinkage, compounding agent dispersion stability, flow characteristics, and uniformity of molded products.

[Prior art and its problems] RIM (Reaction Injection Molding, ie, reaction injection molding), LIM (Liquid Injection Molding, ie, liquid resin injection molding), RTM (Resin Transfer Molding, ie, resin transfer molding) and cast molding (ie, Although resin and composite material molding methods such as cast molding) have been known per se for a long time, the use of polymerizable liquid compositions as raw materials makes it possible to save energy in large plastic parts and composite materials. In recent years, the molding method has attracted particular attention (see, for example, “Thermosetting Resins”, vol. 7, No. 2, pp. 87-98).

The following are known as typical resins (systems) used for such RIM, LIM, RTM and the like.

RIM; polyurethane resin, polyurea resin, nylon resin, unsaturated polyester resin (including chemically modified composition), epoxy resin, phenol resin, metathesis (dicyclopentadiene) resin, oxazoline / oxazine resin LIM; liquid rubber, silicone Rubber RTM; unsaturated polyester resin (including chemically modified composition), epoxy resin, unsaturated polyurethane resin, bismaleimide resin, diaryl phthalate resin Conventionally, these liquid monomers or prepolymers are cured as necessary. Additives, curing accelerators, polymerization catalysts, polymerization accelerators, inhibitors, chain transfer agents, sensitizers, release agents, rubber components, etc., and compounded in a one-pack, two-pack or three-pack configuration , As it is in the state of liquid monomer (or prepolymer) for molding. At this time, heat resistance and mechanical Gender, for the purpose of improving physical properties such as surface properties, for example,
Incorporation of an inorganic filler such as calcium carbonate powder or short glass fiber has been performed.

However, many of the above-mentioned inorganic fillers have a large specific gravity, and are effective for relatively high-viscosity ones such as a melt-molded polymer. However, a resin liquid (monomer or oligomer) is placed in a mold such as RIM. In the case of the molding method in which the filler is supplied at a relatively low viscosity, the filler gradually sinks and hardens until the hardening is reached. There was a disadvantage that the properties were different. In particular, in the case of a large molded product whose curing time is intentionally delayed, securing homogeneity is an important technical problem. Further, there is a problem in that the filler is settled and ubiquitous in the molded article, so that extreme heat is easily generated locally during curing. Further, by containing the inorganic filler, the specific gravity of the molded article is increased, and the light weight, which is an advantage of the composite material, is impaired.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems in a polymerizable composition for molding using a conventional inorganic filler, to reduce local heat generation during a curing reaction, and to reduce molding It is an object of the present invention to provide a novel polymerizable composition for molding using an organic filler capable of preferably improving the surface properties and dimensional stability of a product.

[Constitution of the Invention] The object of the present invention as described above is to provide a polymerizable composition for molding (A) capable of forming a resin by curing without substantially producing a volatile component, and a fine polymer (B). A suspension composition comprising a polymerizable composition for molding (A) or a solution of a polymer of liquid polymerizable components (A ') and a polymer of (B) constituting a part of the composition (A) by a precipitation method. This is achieved by a polymerizable composition for molding, characterized by being prepared by:

Polymerizable composition for molding (A) and fine polymer (B)
For the type of the component polymer, the following materials well known to those skilled in the art can be referred to, and each will be described in detail below.

・ 10188 chemical products (Chemical Daily) ・ Encyclopedia of Chemical Indusrty (Ullmann) ・ Encyclopedia of Chemical Technology (Kirk-Othmer) About composition (A) The composition (A) in the present invention is a liquid A composition mainly composed of a monomer and / or a prepolymer is used. Specifically, the composition is substantially composed of a monomer and / or a prepolymer and a curing agent / catalyst for curing the same, and is substantially volatile in a molding step. A composition capable of simultaneously performing curing (polymerization) and shaping without releasing components (in a relatively short time), and which is substantially a liquid at the molding temperature is used.

First, the types of the composition (A) that can be preferably used in the present invention will be described in detail.

As the component (A), a composition mainly composed of a liquid monomer and / or prepolymer is used. Such a composition substantially comprises a monomer and / or a prepolymer and a curing agent / catalyst for curing the same, and cures (polymerizes) and forms without substantially releasing volatile components in the molding step. Which can be carried out simultaneously (in a relatively short time), and which is substantially liquid at the molding temperature.

Suitable monomers and / or prepolymers include, for example, polyurethane / polyurea resins, nylon resins, unsaturated polyester resins, vinyl ester resins, epoxy resins, polycyclopentadiene resins used in RIM, LIM, RTM, etc. as described above. Examples include monomers and / or prepolymers used in oxazoline / oxazine resins, bismaleimide resins, and silicone resins.

These may be used alone or in combination of two or more.

Generally, these liquid monomers and / or prepolymers include curing agents and catalysts for curing, that is, curing agents, curing accelerators, catalysts (including radical initiators), and polymerization accelerators (for radical initiators). At least one selected from the group consisting of:

The composition may optionally contain a chain transfer agent, a sensitizer,
The additives (C) such as a release agent and a stabilizer are blended in a one-pack, two-pack or three-pack configuration. In the present invention, a specific organic filler described in detail below, namely, One or more of the fine polymers (B) are contained in one liquid or a plurality of liquids.

In the present invention, in preparing the polymerizable composition for liquid molding (A), a (liquid) polymerizable monomer and / or prepolymer (A ′) constituting a part of the composition is started. It can be used as a raw material. For example, a fine polymer is prepared by a precipitation method using a liquid polymerizable monomer such as styrene in an unsaturated polyester system and a solution of a polymer component of the fine polymer (B) (hereinafter, referred to as B polymer). It is also possible to employ a method of adding and dissolving the unsaturated polyester to the fine polymer-containing suspension obtained later to form the polymerizable composition for molding of the present invention. Representative examples are shown in the table below.

Preparation of Fine Polymer (B) The fine polymer (B) in the present invention can be produced, for example, by the following method.

A liquid polymerizable component (A ′) in the polymerizable composition for molding (A) or a part of the composition (A) is mixed with a solution of the B polymer (B solution) to obtain a fine polymer (B). The method of precipitating. (If precipitation of the fine polymer does not occur, the fine polymer is precipitated by distilling and removing the solvent of the solution B.) The polymerizable composition for molding (A) or a part of the composition (A) The B polymer (in a solid state) and a solubilizing solvent or a solubilizing aid capable of dissolving the polymer are added to the liquid polymerizable component (A ′) to be prepared, and a uniform solution is once prepared. Thereafter, the solubilizing solvent or the solubilizing aid is distilled off and removed to precipitate the fine polymer (B).

As the B polymer that can be used in the present invention, a thermoplastic polymer that satisfies the above requirements among thermoplastic polymers can be used in a wide range of applications. However, as is clear from the object, configuration, operation and effect of the present invention,
The solvent, solubilizing solvent or solubilizing aid used in the above-mentioned method is difficult to remove and evaporate, which inhibits the curing of the finally obtained suspension composition and significantly impairs the properties of the molded article. It must not be. In addition, such a trace amount of the additive must not cause the above-mentioned inhibition of curing and deterioration of molded article characteristics. Further, at the time of distilling off the solvent of the B polymer, a part or a substantial amount of the liquid component of the composition (A) is distilled off simultaneously or in advance, and the fluidity of the suspension composition of the present invention is significantly impaired. must not.

From the above requirements, in the case of the distillation method most commonly applied in the present invention, it is desired to use a solvent having a lower boiling point than the liquid component of the composition (A) as the solvent for the B polymer. However, other solvents can also be used in special cases such as adsorption and cryogenic separation.

Solvents for dissolving various polymers are well known to those skilled in the art and will not be described in detail, but typical combinations (polymer and solvent) are shown below. (J. Brandrup and EHImmergut
Ed., Polymer Handbook, Interscience Publishers, etc.).

The fine polymer (B) is prepared by using the liquid composition (A) and the solution of the B polymer in the present invention, as described above in part. (If no precipitation of fine particles occurs at this time) (B) is precipitated by removing the solvent for the B polymer under normal pressure or reduced pressure. In any case, when the precipitation of (B) occurs, the form (particles or pulp / fibrous), size, etc. of the precipitated (B) are changed by applying a shearing force by stirring or the like. I can do it. For example, when the precipitation of (B) occurs very slowly, a gel that has poor fluidity under non-stirring can be prepared by precipitating under stirring to prepare a relatively fluid suspension. It is possible. Addition of a solid B polymer as a so-called “core” for the purpose of accelerating the precipitation can be carried out as required.

In some cases, the B polymer is mixed in a solid state with the polymerizable composition for molding (A) (or a liquid component thereof) and a solubilizing solvent or a solubilizing auxiliary liquid to form a uniform solution,
The present invention can be applied to the present invention as long as the solubilizing solvent or the solubilizing aid can be removed by means of distillation, adsorption or the like to precipitate (B).

Further, for example, a method of blending the B polymer solution and (A) in the form of a solvent-soluble precursor polymer, such as polyamic acid in polyimide, and then precipitating a fine polymer by means such as ring closure with heating can also be applied to the present invention. .

The size / morphology of the fine polymer (B) in the suspension composition of the present invention affects various physical properties (and moldability) of a molded article finally obtained by a curing reaction. As mentioned above,
In addition to the shear force at the time of precipitation 4, polymer concentration, temperature at the time of precipitation,
The main factors are the size, morphology, and amount of the 'nucleus' added as needed.

From the intended use of the suspension composition of the present invention, the form of the fine polymer (B) may be spherical, film tape, pulp, fibrous, whisker, or the like.

The size of the diameter or width is preferably 1 μm.
m or less (the maximum length direction may be more than mm), more preferably 0.1 μm or less, and 0.01 μm depending on the purpose of use.
The following is preferred.

Further, the content of the fine polymer (B) is determined according to the composition (A)
It is appropriately selected depending on the type of the polymer (B), the shape of the molded product, the application, and the like.
50 parts by weight are preferably used.

[Effects of the Invention] The polymerizable composition for molding of the present invention having the above-described structure,
The composition (A) is used as a matrix, in which the fine polymer (B) is uniformly dispersed, and the cured resin obtained from this composition is such that the fine polymer (B) has a higher content than the inorganic filler. And low specific gravity, and has low sedimentation during storage in a liquid state and during injection filling into a mold or the like, so that local heat generation during curing is small. Furthermore, because of its excellent physical and chemical affinity and reactivity with the resin obtained by the curing reaction of the liquid monomer, the molding shrinkage is small compared to the case without such a filler. The product exhibits excellent heat resistance and mechanical properties.

[Examples] Hereinafter, the present invention will be described in detail with reference to examples. In Examples, PHR (per hundred resin) indicates parts by weight of the component (B) with respect to 100 parts by weight of the reference substance such as the component (A).

Example 1 A 10% by weight solution of PC (polycarbonate) in MC (methylene chloride) was prepared. Epoxy monomer shown below, UPE
(Unsaturated polyester) / styrene, styrene and
The mixture was mixed to a PC concentration, and MC was obtained from the resulting mixed solution.
Was distilled off under reduced pressure to prepare a suspension composition having the following properties. The viscosity of the composition is expressed in centipoise measured at 70 ° C.

When each polymerizable composition for molding containing a PC fine polymer obtained as described above was cured with a curing agent and a radical initiator, local heat generation during curing was small, and the obtained molded product was
It was tougher than those without PC.

Claims (2)

(57) [Claims] 1. A suspension composition comprising a polymerizable composition for molding (A) and a fine polymer (B) capable of curing to form a resin without substantially producing a volatile component, The fine polymer (B) is a solution containing the polymerizable composition (A) or a liquid polymerizable component (A ′) constituting a part of the polymerizable composition (A) and a polymer of (B). , A polymerizable composition for molding containing a fine polymer, which is prepared by a precipitation method. 2. The polymerizable composition for molding according to claim 1, wherein the fine polymer (B) is a precipitate composed of a thermoplastic polymer.