JPH0698635B2 - Method for producing molded resin product containing inorganic filler - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an inorganic filler-containing resin molded article.

<Prior Art> Resins containing an inorganic filler are widely used for building materials and interior decoration.

Particularly in recent years, the demand for so-called artificial marble that has a marble-like appearance is becoming particularly strong in applications such as vanities, kitchen sinks, bathtubs, and other sanitary products.

As a method for producing them, alumina, hydrated alumina, calcium carbonate, gypsum, marble powder, unsaturated polyester resin prepolymer with inorganic filler such as titanium oxide,
Alternatively, a method is used in which a partial polymer of methyl methacrylate, so-called methacrylate syrup, is mixed, a polymerization initiator is added, and the mixture is poured into a preformed casting mold and heat-cured.

However, this method has a long polymerization and curing time and is inefficient, and improvement in productivity is desired.

Further, since the polymerization and curing time is long and the inorganic filler precipitates during the polymerization, the appearance, mechanical properties, thermal properties, etc. of the molded product are partially different, causing problems such as warpage and twist.

Generally, the polymerizable composition of the inorganic filler and the unsaturated polyester resin prepolymer or methacrylate syrup,
Since the specific gravities are different, the dispersion due to the sedimentation of the inorganic filler tends to be non-uniform.

As a measure against this, in order to reduce the sedimentation of the inorganic filler, the viscosity of the liquid of the polymerizable composition can be increased as much as possible, or the inorganic filler particles as disclosed in JP-A-60-84364 can be used. In order to improve the dispersibility of the inorganic filler, it is possible to add a dispersant or to reduce the particle size of the inorganic filler.
A method of devising a molding method is performed as disclosed in Japanese Patent Publication No. 217664.

Furthermore, when carrying out polymerization curing of a methacrylate syrup using an inorganic filler such as a metal oxide or a hydroxide, the polymerization is significantly inhibited by the filler, the polymerization curing time becomes long, or the polymerization stops in the middle. A phenomenon such as being lost may occur.

If the polymerization is not sufficient, the heat resistance of the molded product is lowered due to the remaining monomer, the chemical resistance is deteriorated, and defects such as cracks are generated.

Further, when the amount of residual monomer increases, the problem of odor also occurs and the commercial value is lost.

In order to improve these, several kinds of polymerization initiator systems have hitherto been proposed.

JP-B-50-22586 discloses that when a system of a metal salt of maleic acid hemiperester and a mercaptan chain transfer agent uses alumina hydrate as an inorganic filler, the water contained in the inorganic filler is polymerized. As the inhibition can be improved,
It is shown.

Further, JP-A-53-81589 and JP-A-53-115768 show that an organic peroxide and a tertiary amine can be smoothly polymerized and cured even at room temperature.

Further, in JP-A-60-103065, an organic peroxide and a quaternary ammonium salt are used as a polymerization initiator system.
A method of improving the coloring and discoloration, which is problematic with organic peroxides and tertiary amines, and which is polymerized and cured at a temperature below 0 ° C. is shown.

However, although these methods are improved in that the polymerization and curing by the inorganic filler is insufficient, there is a problem of coloring and discoloration, and the polymerization and curing time generally takes several hours, Not a productive method.

<Problems to be Solved by the Invention> An object of the present invention is to shorten the polymerization and curing time in the production of an inorganic filler-containing resin molded product, thereby improving the productivity and the inorganic filler during polymerization. The purpose is to reduce sedimentation and improve the non-uniformity of the appearance, mechanical properties and thermal properties of the molded product.

It is also intended to improve the partial deformation of the molded product due to the shrinkage phenomenon that occurs when the polymerization and curing are carried out in the mold, especially the poor surface condition.

<Means for Solving Problems> The present invention is to inject into a mold a reactive raw material mainly composed of a vinyl monomer and / or a vinylidene monomer containing a polymer or not and an inorganic filler. A method for producing an inorganic filler-containing resin molded article, which comprises polymerizing and curing under pressure.

The vinyl monomer or vinylidene monomer referred to in the present invention means a monomer having at least one polymerizable unsaturated carbon bond in the molecule, and one polymerizable unsaturated bond in the molecule. Examples of the vinyl bond or vinylidene monomer containing a carbon bond include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic acid. Examples are phenyl, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, bornyl (meth) acrylate, furfuryl (meth) acrylate, isobornyl (meth) acrylate, and adamantane (meth) acrylate.

Aliphatic alcohols, alicyclic alcohols, heterocyclic alcohols, aromatic alcohols, or acrylic acid esters and methacrylic acid esters with phenols; vinyl nitriles such as acrylonitrile, methacrylonitrile, and crotnitrile; vinyl acetate, propion Vinyl esters such as vinyl benzoate; styrene, α
-Aromatic vinyl compounds such as methyl styrene and p-still styrene; 2-chlorostyrene, 4-bromostyrene,
Aromatic vinyl compounds having halogen-substituted aromatic rings such as 4-bromophenyl (meth) acrylate and 2,4,6-tribromophenyl (meth) acrylate, halogen-containing-acrylic acid esters, methacrylic acid esters; acryl Unsaturated carboxylic acids such as acids, methacrylic acid, maleic acid and maleic anhydride and anhydrides thereof; and imidized products such as phenylmaleimide, cyclohexylmaleimide, orthomethylphenylmaleimide, ethylmaleimide and lacrylmaleimide.

Further, such vinyl monomer or vinylidene monomer,
These can be used alone or in combination, and further, other copolymerizable monomers can be used in combination.

Examples of other copolymerizable monomers include monomers having a functional group such as 2-hydroxyl ethyl (meth) acrylate, glycidyl methacrylate, and diaminoethyl (meth) acrylate.

Furthermore, in order to improve the strength, chemical resistance and heat resistance of the molded product, it is necessary to use a vinyl monomer or a vinylidene monomer containing two or more polymerizable unsaturated carbon bonds in the molecule in combination. Is preferred.

Examples of the polyfunctional monomer having two or more polymerizable unsaturated carbon bonds in the molecule include ethylene glycol,
Propylene glycol, or oligomers thereof, other dihydric or higher alcohols, or esters of phenol and alkylene oxide adducts thereof with acrylic acid or methacrylic acid; and dihydric or polyhydric alcohols and glycidyl group-containing (meth ) Acrylate ring-opening adduct; and dibasic acid and glycidyl group-containing (meth)
Ring-opening adducts of acrylates; further, arylmethacrylate, divinylbenzene and the like.

The polyfunctional monomer is preferably used in the range of 0.1 to 30% by weight based on the total monomers.

The vinyl monomer or vinylidene monomer can be used as a reactive raw material by mixing the monomer as it is with the inorganic filler, but the polymerization curing time is shortened, the inorganic filler is prevented from settling, and the handling is easy. For this reason, it is preferable to use a so-called syrup in which a polymer is dissolved and contained.

The type of the polymer does not necessarily have to be the same as the type of the monomer used, and may be selected from the physical properties of the molded product and can be dissolved in the monomer used.

The content of the polymer in the syrup is about 8 to 40% by weight.

If it exceeds 40% by weight, the viscosity is high and handling becomes difficult, which is not preferable.

A known method may be used for producing a syrup, for example, a method of adding a polymerization initiator or the like to a monomer for polymerization, and stopping the polymerization at an appropriate polymerization rate, or dissolving a predetermined amount of the polymer in the monomer. There are ways.

The inorganic filler used in the present invention can be various natural or artificial fillers, examples of which include alumina,
Silica-based substances such as quartz, cristobalite and tridymite, hydrates such as aluminum hydroxide, magnesium hydroxide, calcium aluminate hydrate, aluminates, aluminosilicates, gypsum, fluorite, kyanite, olivine Stones, wollastonite, apatite, minerals such as calcite, cast iron,
Metals such as zinc alloys, aluminum, bronze and steel, and man-made substances such as glass, ceramics, slag and coke and carbon-based substances.

In the method of the present invention, the inorganic filler particles used in the present invention are injected under pressure into the mold and polymerized and hardened in a short time. Therefore, in the conventional production method, there is a problem in terms of sedimentation and handling. Particles having a particle size of 100 μm or more can be used.

Generally, an inorganic filler having a particle size of 1 to 200 is suitable in terms of handling and appearance.

The amount of the inorganic filler is preferably 75 to 30% by weight with respect to the reactive raw material mainly containing the vinyl monomer and / or the vinylidene monomer and the inorganic filler with or without the polymer. .

If it is more than 75% by weight, the viscosity of the reactive raw material is high, it becomes difficult to handle, and air bubbles are entrained during pouring into the mold, resulting in poor appearance.

If it is less than 30% by weight, the appearance becomes mottled, which is not preferable.

As the polymerization initiator used for polymerizing the monomer in the present invention, benzoyl peroxide, lauroyl peroxide, diacyl peroxide such as succinic peroxide: di-t-butyl peroxide,
Dialkyl peroxides such as t-butyl cumyl peroxide and dicumyl peroxide: t-butyl peroxyacetate, t-butyl peroxypivalate, t
-Peroxyesters such as butylperoxybenzoate and t-butylmaleic acid hemiperester: Hydroperoxides such as t-butylhydroperoxide and cumene hydroperoxide: Organic compounds such as ketone peroxide such as methylethone peroxide Examples thereof include peroxides and azo compounds such as 2,2-azobisisobutyronitrile and 2,2-azobis (2,4-dimethylvaleronitrile).

As the polymerization initiator, 0.01 to 0.01 with respect to the vinyl and / or vinylidene monomer containing or not containing a polymer.
It can be used in the range of 10% by weight.

Further, in the present invention, in addition to the above-mentioned polymerization initiator, a polymerization accelerator and an auxiliary component of the polymerization accelerator can be used.

Such polymerization accelerators include reducing substances, and auxiliary components of the polymerization accelerators include metal-containing compounds, amines or amine-halogen compounds.

Examples of the reducing agent which is a polymerization accelerator include mercaptans such as laurimercaptan, octyl mercaptan, 2-ethylhexyl mercaptan, glycol dimercaptoacetate and glycol dimercaptopropionate: thioureas such as dibutylthiourea and tetramethylthiourea: Examples thereof include phosphite esters such as trimethyl phosphite and tri-n-butyl phosphite.

Further, as the metal compound as an auxiliary component of the polymerization accelerator,
Examples thereof include salts of organic acids such as naphthenic acid of metals selected from iron, copper, cobalt, nickel, tin, aluminum and antimony, organometallic complexes such as acetylacetone and phenylacetylacetone, and allyl compounds of these metals.

Further, as the amine or the amine-halogen compound,
Examples thereof include primary amines, secondary amines, tertiary amines, hydrogen halide salts thereof, and quaternary ammonium halides.

The polymerization accelerator and the auxiliary component of the polymerization accelerator are 0.00001 to 1 with respect to the vinyl monomer and / or vinylidene monomer containing or not containing the polymer in the mixed raw material liquid.
It can be used in the range of% by weight.

In the present invention, in order to quickly complete the polymerization and curing,
When the polymerization initiator and the polymerization accelerator are used in combination, a raw material liquid containing a polymerization initiator in a part of the reactive raw material and a polymerization accelerator other than the polymerization initiator in the balance of the reactive raw material. It is advisable to employ a method in which the raw material liquid thus obtained is mixed immediately before injection into the mold.

The auxiliary component of the polymerization accelerator may be added to any raw material liquid.

Further, the reactive raw material, if necessary, an ultraviolet absorber,
It is also possible to add a heat stabilizer, a lubricant, a release agent, a colorant, a surfactant, a dispersant such as a silane coupling agent or a functional polymer.

In the present invention, the mixing of the reactive raw material containing the polymerization initiator and the reactive raw material containing the polymerization accelerator other than the polymerization initiator needs to be performed at a temperature of 50 ° C. or less in a short time. .

Examples of the mixing method for this purpose include a collision mixer, a dynamic mixer, and a static mixer. With such a mixing method, the reactive raw materials can be uniformly mixed in a short time, and the inorganic filler can be uniformly mixed. Dispersion and polymerization and curing can be made uniform, and further, the progress of polymerization during mixing can be prevented.

A known liquid delivery device can be used to supply the reactive raw material to the mixing device.

For example, it is possible to use a pressurization quantitative delivery device such as a gear pump, a piston pump, an axial pump, a diaphragm pump or the like, or a pressurization delivery by a compressed gas, and the delivery device quantitatively pressurizes the raw material liquid into the mixing device. It is supplied, the reactive raw materials are uniformly mixed, and the mixture is further injected under pressure into the frame.

In the present invention, the pressure injection into the mold may be carried out by directly and continuously applying pressure to the mold by attaching the above mixing device to the mold, or from the mixing device through a conduit. Can also pressurize and inject the reactive raw material sent from the mixing device again.

By such pressure injection, conventionally, even with a highly viscous reactive raw material in which bubbles that are difficult to inject are easily entangled or a highly active reactive raw material that is easily polymerized, a mold for obtaining a large-sized molded product can be obtained. Even when it is used, it can be injected in a short time.

The injection pressure of the reactive raw material into the mold is at least
A pressure of 10 kg / cm ² is desirable.

The higher the injection pressure, the faster the injection speed, which is advantageous. However, if the injection pressure is too high, entrainment of bubbles occurs.
It is preferably about 150 kg / cm ² .

Mold, resin mold, rubber mold, wood mold, etc. are used as the mold,
A mold is particularly preferable in terms of accuracy and durability.

The shape of the mold is selected to match the shape of the molded product to be obtained.

During polymerization and curing, the reactive liquid causes a shrinkage phenomenon, so
It is desirable to pressurize the inside of the mold during the polymerization and curing period.

Pressurization in the mold is a method of compressing by a mold structure capable of reducing the space volume filled with the raw material liquid in the mold by an external force-that is, in-mold compression used in compression molding or injection compression molding. The method or a method of introducing a compressed fluid such as compressed air from the outside into the raw material liquid in the mold is disclosed in JP-A-56-146743, JP-A-58-201627, and JP-A-59- Known methods include those disclosed in Japanese Patent No. 106939 and Japanese Patent Laid-Open No. 59-59427.

The pressure conditions during the polymerization curing, the reactive source of the mold is preferably pressurized at a pressure of 1 to 100 kg / cm ^2, further, it is more preferable that the pressure of 10 to 50 kg / cm ² .

At a pressure of less than 1 kg / cm ² , with respect to the shrinkage of the raw material liquid during polymerization and curing, the mold cannot be sufficiently followed, it is difficult to accurately transfer the mold, and the boiling of the monomer easily occurs,
When the pressure exceeds 100 kg / cm ² , the molded product is likely to be distorted, which is not preferable.

In the present invention, the polymerization and curing are uniformly carried out by heating and pressing in the mold, there are no defects such as bubbles and dents on the surface and the inside of the molded product, and the polymerization shrinkage is compensated for. It is possible to form a molded product in which the shape is accurately inverted, the accuracy is high, and the distortion is small.

The polymerization curing temperature is preferably 50 ° C to 150 ° C.

This temperature adjustment is carried out by heating the heater by embedding a heater in the mold and heating it, cooling it by air cooling, attaching a jacket or a passage for the heat medium to the mold, and passing hot water or heat oil.

The polymerization time is 80 minutes or less, preferably 15 minutes or less, more preferably 10 minutes or less by selecting conditions such as the type of polymerization initiator and other polymerization accelerator, concentration and temperature of the mold. Be done.

<Effect of the Invention> According to the present invention, a molded product of a vinyl polymer-containing inorganic filler-containing resin can be efficiently manufactured in a short time.

Further, it is possible to obtain a molded product having no unevenness in appearance, mechanical properties and thermal properties due to the sedimentation of the inorganic filler.

Further, it is possible to obtain an excellent molded product having no appearance defect such as a dent due to polymerization shrinkage.

The method of the present invention is particularly suitable for the production of bathroom vanities, kitchen sinks, bathtubs, and other sanitary products, since it is easy to produce large molded products and has good productivity.

<Example> Example 1 (Preparation of original syrup) 20 kg of methyl methacrylate was mixed with methyl methacrylate resin (
Mipex -B MH Sumitomo Chemical Co., Ltd. 5 kg
Mix and dissolve with stirring, polymer content 20%, viscosity 1
I got the original syrup of Izu.

(Preparation of raw material solution A) 1.8 kg of the above raw syrup, 0.2 kg of ethylene glycol dimethacrylate, and 20 k of t-butyl peroxybenzoate
g, and then 10 g of a solution of dibutylamine hydrochloride dissolved in diethylene glycol at a concentration of 8% by weight to make a uniform solution, and gradually add 3 kg of silica powder having an average particle size of 120μ to disperse the solution evenly. A raw material liquid A was prepared.

The viscosity of this raw material liquid A was 40 poise.

(Preparation of raw material liquid B) To 2 kg of the above-mentioned raw syrup, 10 g of glycol dimercaptoacetate was added, and further 1 g of a solution prepared by dissolving 1% by weight of copper naphthenate (Cu content 10%) in methyl methacrylate was added, and a uniform solution was added. And the average particle size used in the above raw material liquid A
3 kg of 120 μm silica powder was gradually added and uniformly dispersed to prepare a raw material liquid B.

The viscosity of this raw material liquid B was 60 poise.

(Polymerization molding) While introducing each of the above raw material liquids A and B to 120 kg / cm ² using a piston-cylinder type pump, they are introduced into a collision mixer having a nozzle having a diameter of 1.4 mm and facing each other with a distance of 14 mm, In the collision mixer, the raw material liquids A and B are 1:
Pressurized and mixed at a weight ratio of 1 and set to 80 ° C 500
It was poured into a mold of × 500 × 10 mm.

The time required for injection was about 5 seconds.

After pouring, close the formwork and gradually pressurize the inside.
The temperature of the raw material liquid in the mold showed the maximum value after 6 minutes while keeping it at kg / cm ^2, and after 8 minutes, the mold was opened to obtain a cured molded body.

The molded body had no defects such as dents on the surface, sedimentation of the filler, and inclusion of bubbles, and had good gloss.

Example 2 A raw material liquid was prepared and polymerized in the same manner as in Example 1 except that aluminum hydroxide having an average particle size of 15 μ was used instead of the silica powder having an average particle size of 120 μ used in Example 1. .

The viscosities of the raw material liquids A and B obtained in the same manner as in Example 1 were 150 poise and 180 poise, respectively.

In addition, pouring into the mold takes about 10 seconds, the raw material liquid shows a peak temperature 8 minutes after the completion of pouring, and after 10 minutes, the mold was opened to obtain a molded body.

The obtained molded product was a polymer having no defects and an excellent appearance as in Example 1.

Example 3 (Preparation of raw material liquid A) To 1.8 kg of the raw syrup prepared in Example 1, 0.2 kg of ethylene glycol dimethacrylate, 30 g of t-butyl maleic acid hemipester, dibutyloctylamine hydrochloride 16
g, acetylacetone-tin 4g to make a uniform solution,
Further, 2.0 kg of magnesium hydroxide having an average particle diameter of 5 μ was gradually added to uniformly disperse the raw material liquid A.

The viscosity of this raw material liquid A was 250 poise.

(Preparation of Raw Material Liquid B) To 2.0 kg of the raw syrup prepared in Example 1, 20 g of 2-mercaptoethanol was added to form a uniform solution, and 2.0 kg of magnesium hydroxide having an average particle diameter of 5 μ was gradually added to the solution.
Raw material liquid B was prepared by uniformly dispersing.

The viscosity of this raw material liquid B was 270 poise.

(Polymerization molding) Using the above-mentioned raw material liquids A and B, in the same manner as in Example 1,
Polymerization was performed.

The pouring into the mold takes about 15 seconds, the raw material solution shows a peak temperature 5 minutes after the completion of the pouring, and after 10 minutes, the mold was opened to obtain a molded product.

The obtained molded body had no defects and had an excellent appearance as in Example 1.

Example 4 (Preparation of original syrup) 2.4 kg of cyclohexyl methacrylate, 1.4 kg of methyl methacrylate, 0.2 kg of styrene, azobisisobutyronitrile
0.8g was mixed and kept at 80 ° C with stirring in the reaction vessel.

When the viscosity of the internal solution reached 1 poise, the reaction was stopped by cooling to obtain a raw syrup containing 3% by weight of the polymer.

(Preparation of Raw Material Liquid A) To 1.8 kg of the above-mentioned raw syrup, 0.2 kg of tetraethylene glycol dimethacrylate, 40 g of t-butylperoxybenzoate, and 4 g of dimethyloctylamine hydrochloride were added to obtain a uniform solution. Add 3kg of 15μ aluminum hydroxide gradually while stirring to evenly disperse,
A raw material liquid A was prepared.

The viscosity of this raw material liquid A was 150 poise.

(Preparation of Raw Material Liquid B) To 2.0 kg of the above-mentioned raw syrup, 20 g of glycol dimercaptopropionate and 5 g of 0.1% by weight of acetylacetone copper dissolved in methyl methacrylate were added to obtain a uniform solution having an average particle size of 3 kg of 15μ aluminum hydroxide was gradually added with stirring to uniformly disperse the raw material liquid B.
Was prepared.

The viscosity of this raw material liquid B was 170 poise.

(Polymerization molding) Using the above-mentioned raw material liquids A and B, a rough dimension as a mold is 60
Molding was carried out in the same manner as in Example 1 except that a mold having the shape of a washbasin with a depth of 0 mm, a depth of 100 mm and a thickness of 10 mm was used.

It takes about 10 seconds to pour into the formwork, and after pouring,
The raw material liquid showed a peak temperature in 10 minutes, and after 15 minutes, the mold was opened to obtain a molded body.

The obtained molded product had an excellent appearance without defects as in Example 1.

Example 5 (Preparation of Raw Material Liquid A) An unsaturated polyester obtained by heating 392 g of maleic anhydride, 323 g of isophthalic acid and 456 g of propylene glycol was dissolved in 1770 g of styrene. To 2000 g of this solution, 40 g of t-butyl peroxybenzoate, 4 g of dimethyloctylamine hydrochloride and acetylacetone copper were added to styrene.
5 g of a 1% by weight dissolved solution was added to form a uniform solution, and 3000 g of aluminum hydroxide having an average particle size of 70 μ was gradually added with stirring to uniformly disperse the raw material solution A.

The viscosity of this raw material liquid A was 250 poise.

(Preparation of raw material liquid B) 1030 g of N-cyclohexylmaleimide, 730 g of methyl methacrylate, tetraethylene glycol dimethacrylate
240 g and glycol dimethylcaptoacetate 15 g were mixed to form a uniform solution, and 3000 g of aluminum hydroxide having an average particle size of 70 μ was gradually added with stirring to uniformly disperse the raw material liquid B.

The viscosity of this raw material liquid B was 50 poise.

(Polymerization Molding) Molding was performed in the same manner as in Example 1 except that the above prepared raw material liquids A and B were used.

It takes about 10 seconds to pour into the formwork, and after pouring,
The raw material liquid showed a peak temperature in 3 minutes, and after 5 minutes, the mold was opened to obtain a molded body.

The obtained molded product had an excellent appearance without defects as in Example 1.

Claims (2)

[Claims] 1. A reactive raw material mainly comprising a vinyl monomer and / or a vinylidene monomer containing a polymer and an inorganic filler is injected under pressure into a mold and polymerized and cured under pressure. A method for producing an inorganic filler-containing resin molded article, comprising: 2. The manufacturing method according to claim 1, wherein pressure injection is performed into the mold at a pressure of at least 10 kg / cm ² .