JP2002003679A - (meth)acrylic smc or bmc, its manufacturing method and (meth)acrylic resin moldings - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic SMC(sheet molding compound) or BMC(bulk molding compound) produced at an appropriate thickening rate and resin moldings excellent in appearance. SOLUTION: A (meth)acrylic SMC or BMC includes (A) a (meth)acrylic monomer or (meth)acrylic syrup, (B) an inorganic filler, (C) a polymer powder having the specific surface area in the range of 0.25-0.95 m2/g and a glass transition temperature of 50. degree. C. or more and (D) a curing agent. The acrylic resin molding is obtained by heating, pressing and curing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a (meth) acrylic SMC (sheet molding compound) or BMC (bulk molding compound), and a (meth) acrylic resin molded product using the same.

[0002]

2. Description of the Related Art A (meth) acrylic resin molded product in which an inorganic filler such as aluminum hydroxide is blended with a (meth) acrylic resin has various excellent properties such as excellent molded appearance, warm touch and weather resistance. It is widely used as artificial marble in counters such as kitchen counters, vanities, waterproof pans, and other architectural uses. As a method for producing this (meth) acrylic resin molded product, a premix in which an inorganic filler is dispersed in a (meth) acrylic monomer or a (meth) acrylic syrup is thickened with a thickener, and rice cake is formed. After forming into a (meth) acrylic BMC, it is cured by heating and pressing (meth)
A method of obtaining an acrylic resin molded product has been conventionally performed. For example, JP-A-10-219069 discloses
A (meth) acrylic BMC using a beaded polymer powder as a thickener is disclosed. However, since the polymer powder used here is in the form of beads, the specific surface area is about 0.1 m ² / g or less, the dissolution rate of the polymer powder in the monomer component is low, and the viscosity increase rate is low. Is extremely slow. Therefore, in this publication, in order to obtain a rice cake in a short time,
By kneading at a temperature of 80 ° C. or higher, the rate of thickening is increased. For this reason, the curing agent cannot be kneaded at the same time, and three steps of a kneading step of components other than the curing agent, a cooling step of the kneaded material, and a mixing step of the curing agent are required, and the process is complicated. there were.

Japanese Patent Application Laid-Open No. 10-279765 discloses a (meth) acryl-based polymer powder having a specific surface area of 1 m ² / g or more obtained by spray drying an emulsion-polymerized emulsion. BMC is disclosed. Since the polymer powder has a large specific surface area of 1 m ² / g or more, the rate of dissolution of the polymer powder in the monomer component is high, and the rate of thickening is extremely high. Therefore, even without heating, the viscosity increases in a short time at room temperature to form a rice cake, so that the curing agent components can be mixed simultaneously at the time of kneading, and the mixing and kneading are performed in one step. It is possible. However, this polymer powder, on the contrary, has too high a thickening rate,
Since the viscosity sharply increases during kneading, shear heat is easily generated. Therefore, among (meth) acrylic monomers,
Low boiling monomers such as methyl methacrylate tend to volatilize during kneading. As a result, the component ratios of the constituent components were different between during the preparation and after the kneaded product was obtained, and there was a tendency that the predicted physical property values at the time of the composition design did not appear.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to mix and knead the constituents at the same time, and to substantially reduce the ratio of the constituents at the time of preparation and after the kneaded material is obtained. An object of the present invention is to provide a (meth) acrylic SMC or BMC having an appropriate thickening rate, a non-stickiness, and good handleability, and an acrylic resin molded product obtained by curing the same.

[0005]

According to the present invention, there is provided a (meth) acrylic monomer or (meth) acrylic syrup (A), an inorganic filler (B), and a specific surface area of 0.25 to 0.
95 m ² / g and a glass transition temperature of 5
Polymer powder (C) having a temperature of 0 ° C. or higher, and curing agent (D)
The present invention relates to a method for producing (meth) acrylic SMC or BMC, which comprises kneading the (meth) acrylic SMC or BMC in a temperature range of 10 to 60 ° C. while mixing and kneading the same.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. In this specification, “(meth) acryl” means “acryl or methacryl”.

The (meth) acrylic monomer or (meth) acrylic syrup (A) used in the present invention has a suitable fluidity when the (meth) acrylic SMC or BMC of the present invention is molded. It is a component to be provided. Component (A)
May be a (meth) acrylic monomer or a (meth) acrylic syrup in which a polymer is dissolved in the (meth) acrylic monomer.

The content of the component (A) is not particularly limited, but is preferably in the range of 5 to 95% by mass based on the total amount of the (meth) acrylic SMC or BMC of the present invention. When the content is 5% by mass or more, the fluidity during molding of the (meth) acrylic SMC or BMC tends to be good,
When the content is 95% by mass or less, the curing shrinkage ratio during molding tends to decrease. Regarding the lower limit of this content,
10 mass% or more is more preferable, and 15 mass% or more is particularly preferable. About the upper limit of this content, 50 mass%
Is more preferably, and particularly preferably 40% by mass or less.

The (meth) acrylic monomer used in the component (A) is a monomer having a methacryloyl and / or acryloyl group or a mixture thereof, and is not particularly limited.

Specific examples of the component (A) include, for example, methyl (meth) acrylate, alkyl (meth) acrylate having an alkyl group having 2 to 20 carbon atoms, and 1 to 3 carbon atoms.
Hydroxyalkyl (meth) acrylate having 20 hydroxyalkyl groups, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, glycidyl methacrylate,
(Meth) acrylic monofunctional monomers such as (meth) acrylic amide; and ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate,
Examples include (meth) acrylic polyfunctional monomers such as trimethylolpropane tri (meth) acrylate and allyl (meth) acrylate.

These can be used alone or in combination of two or more if necessary. Of these, the use of methyl methacrylate as the component (A) is particularly preferred because the resulting resin molded article tends to have a marble-like transparency and depth.

The component (A) includes, in addition to (meth) acrylic monomers, aromatic vinyls such as styrene and divinylbenzene, vinyl acetate, (meth) acrylonitrile, vinyl chloride, maleic anhydride, and maleic acid. And monomers such as maleic acid ester, fumaric acid, fumaric acid ester, and triaryl isocyanurate.

The inorganic filler (B) used in the present invention comprises:
It is a component that gives a marble-like deep texture and heat resistance to a resin molded product obtained by molding an acrylic SMC or BMC.

The content of the component (B) is not particularly limited, but is preferably in the range of 5 to 95% by mass based on the total amount of the acrylic SMC or BMC.

[0015] This is because when the content of the component (B) is 5% by mass or more, the texture and heat resistance of the obtained molded article tend to be good, and the shrinkage rate during curing tends to be low. It is in. On the other hand, when the content is 95% by mass or less, the flowability of the acrylic SMC or BMC during molding tends to be good.

The lower limit of the content is more preferably 20% by mass or more, and particularly preferably 30% by mass or more. Moreover, about an upper limit, 80 mass% or less is more preferable, and 70 mass% or less is especially preferable.

The inorganic filler (B) is not particularly restricted but includes, for example, aluminum hydroxide, silica, fused silica, calcium carbonate, barium sulfate, titanium oxide, calcium phosphate, talc, mica, clay, glass powder and the like. No. These may be appropriately selected and used as needed, and two or more of them may be used in combination. Among them, aluminum hydroxide, calcium carbonate, silica, fused silica, and glass powder are preferable from the viewpoint of the texture of the obtained resin molded product.

The polymer powder (C) used in the present invention comprises:
The specific surface area is in the range of 0.25 to 0.95 m ² / g, and the glass transition temperature (hereinafter, referred to as Tg) is 50 ° C.
The above polymer powder.

This component (C) is a (meth) acrylic S
A thickener component for imparting an appropriate viscosity to MC or BMC. At least a part of the polymer powder (C) is dissolved in the (meth) acrylic monomer (A), It acts as a thickener by increasing the viscosity.

The specific surface area of the polymer powder (C) used in the present invention is in the range of 0.25 to 0.95 m ² / g. When the specific surface area is 0.25 m ² / g or more, mixing and kneading of the components can be performed simultaneously. Also,
When it is 0.95 m ² / g or less, the components (A), (B),
The viscosity rise during mixing and kneading of (C) and (D) is gradual, and shear heat is less likely to be generated. As a result, the (meth) acrylic SMC or B
The production of MC becomes possible.

The term "component ratio" in the present invention refers to the content of each component at the time of preparation (hereinafter referred to as "prepared amount (X)") in the obtained (meth) acrylic SMC or BMC. (Hereinafter referred to as “component amount (Y)”). In the (meth) acrylic SMC or BMC of the present invention, the component ratio of the constituent components is in a range that does not substantially change.

In the present invention, the ratio (Y / X) of the component amount (Y) to the charged amount (X) is not particularly limited, but is preferably 70% by mass or more. When this ratio is 70% by mass or more, there is a tendency that molded articles obtained by molding (meth) acrylic SMC or BMC have excellent physical properties. The lower limit of the ratio (Y / X) of the amount of the component (Y) to the amount of charge (X) is more preferably 80% by mass or more, further preferably 90% by mass or more, and more preferably 95% by mass. It is particularly preferable that the above is satisfied.

When the specific surface area of the polymer powder (C) used in the present invention is less than 0.25 m ² / g, the rate of thickening becomes extremely slow, and it is difficult to obtain a rice cake having good handleability. There is a tendency that the reaction system must be heated to about the time or the decomposition temperature of the curing agent. Therefore, component (A),
There is a tendency that the curing agent (D) cannot be mixed and kneaded at the same time as (B) and (C).

Further, the specific surface area of the polymer powder (C) is 0.5.
If it exceeds 95 m ² / g, the thickening rate is too fast,
Since the viscosity sharply increases during mixing and kneading, shear heat tends to be easily generated. When this shear heat is generated, low-boiling monomer components such as methyl methacrylate of the (meth) acrylic monomer (A) are volatilized during kneading, and the amount of the component (Y) The ratio (Y / X) to the charged amount (X) tends to decrease.

The lower limit of the specific surface area of the polymer powder (C) is as follows:
0.3 m ² / g or more is preferable, 0.35 m ² / g or more is more preferable, and 0.4 m ² / g or more is particularly preferable.
The upper limit is preferably 0.9 m ² / g or less, and 0.8 m ² / g or less.
5m or less, more preferably ² / g, 0.8m ² / g or less is particularly preferred.

The polymer powder (C) which is a component of the (meth) acrylic SMC or BMC of the present invention has a Tg of 50.
° C or higher.

The Tg (° C.) of the polymer powder (C) used in the present invention refers to the n kinds of the constituents when the polymer component is a copolymer polymerized from n kinds of monomers. Is calculated by the following formula (I) based on the Tg (° C.) of the homopolymer of the monomer component.

[0028]

(Equation 1)

Tg: glass transition temperature of copolymer (° C.) Tg _(i) : glass transition temperature of homopolymer of i component (° C.) w _i : mass ratio of i component, Δw _i = 1

If the polymer powder (C) has a Tg of 50 ° C. or higher, the resulting (meth) acrylic SMC or B
The viscosity attained by the MC becomes high, and a sticky product having good stickiness and good handleability can be obtained. In addition, a resin molded product made of a (meth) acrylic SMC or BMC using the component (C) has good heat resistance, a small coefficient of linear expansion, and good dimensional stability.

If the Tg of the polymer powder (C) is lower than 50 ° C., the viscosity of the resulting (meth) acrylic SMC or BMC will be low, the stickiness will be high, and the stickiness will tend to be poor in handling. It is in. In addition, a resin molded product made of a (meth) acrylic SMC or BMC using this component (C) has poor heat resistance, is deformed when it is released from a mold, and has a large linear expansion coefficient. Dimensional stability tends to be poor.

The lower limit of the Tg of the component (C) used in the present invention is preferably 60 ° C. or higher, more preferably 65 ° C. or higher, and particularly preferably 70 ° C. or higher. The upper limit of the Tg is not particularly limited, but is preferably 150 ° C. or lower.
120 ° C. or lower is more preferable.

The structure of the polymer powder (C) used in the present invention is not particularly limited, may be a uniform particle structure having a uniform composition, and may be composed of a core layer and a shell layer having different compositions and molecular weights. A so-called core / shell structure may be used. When the polymer powder (C) has a core layer / shell layer structure, the average value of Tg of the core layer and Tg of the shell layer is 5
The temperature is preferably 0 ° C. or higher. The average value of Tg as referred to herein is a value obtained by averaging the Tg of the core layer and the Tg of the shell layer by their respective weight ratios.

In the present invention, the content of the polymer powder (C) is not particularly limited, but is preferably in the range of 0.1 to 40% by mass based on the total amount of the (meth) acrylic SMC or BMC.

When the content is 0.1% by mass or more,
There is a tendency for a high thickening effect to be obtained.
In the following cases, (meth) acrylic SMC or BMC
Tends to have a good kneading property when producing. The lower limit of the content is more preferably 1% by mass or more, and particularly preferably 3% by mass or more. For the upper limit,
It is more preferably at most 30% by mass, particularly preferably at most 20% by mass.

As the polymer constituting the polymer powder (C), various polymers can be appropriately selected and used as needed.
Although not particularly limited, a (meth) acrylic polymer is preferable from the viewpoint of compatibility with the (meth) acrylic monomer (A).

As the constituent components of the polymer (monomer used for polymerization), the above-mentioned (meth) acrylic monomer (A)
The monofunctional monomers and / or polyfunctional monomers listed in can be used, and if necessary, a homopolymer polymerized alone may be used, or two or more thereof may be used in combination. A copolymer may be used.

The average particle size of the polymer powder (C) is not particularly limited, but is preferably in the range of 10 to 500 μm. When the average particle diameter is 10 μm or more, the handleability of the polymer powder tends to be good. When the average particle diameter is 500 μm or less, the polymer powder (A)
There is a tendency that the undissolved residue in the components tends to disappear, and the appearance of the obtained molded article, particularly gloss and surface smoothness tend to be good.

The lower limit of the average particle diameter is 30
μm or more is more preferable, and 70 μm or more is particularly preferable. The upper limit is more preferably 350 μm or less, and particularly preferably 200 μm or less.

In the present invention, the weight average molecular weight of the polymer powder (C) is not particularly limited, but as the weight average molecular weight increases, the (meth) acrylic SMC or BM of the present invention increases.
The thickening effect of C increases and the SMC or BM
The (meth) acrylic resin molded product obtained from C tends to have good hot water resistance and impact resistance.

Therefore, the weight average molecular weight of the polymer powder (C) which is a component of the present invention is preferably 10,000 or more, and 5,000,000 or less in view of the kneadability of the (meth) acrylic SMC or BMC of the present invention. Is preferred. The lower limit of the weight average molecular weight is more preferably 100,000 or more, and particularly preferably 500,000 or more. The upper limit is more preferably 4,000,000 or less, particularly preferably 3,000,000 or less.

The method for producing the polymer powder (C) used in the present invention is not particularly limited, but an emulsion polymerization method is preferred.
The method of obtaining a powder from the emulsion obtained by emulsion polymerization is not particularly limited, but it is preferable that the powder be formed by coagulation.

The method of solidifying the polymer powder (C) by coagulation is not particularly limited, and may be solidified by a known method such as a rapid solidification method, a liquid crosslinking method, or a slow solidification method.
Above all, the polymer powder (C) used in the present invention can control the specific surface area of the polymer powder (C) by appropriately selecting the powdering method and conditions according to the Tg of the polymer. Because of the tendency, solidification by a liquid crosslinking method is preferred.

The coagulant used for pulverization by the coagulation method is not particularly limited, and an acid or a salt can be used. The coagulant is appropriately selected depending on the surfactant used in the emulsion polymerization. And use it. For example, specific examples of the acid include sulfuric acid, and specific examples of the salt include aluminum sulfate, calcium acetate, and magnesium sulfate.

The temperature at which the emulsion-polymerized emulsion is coagulated is not particularly limited, and may be coagulated at or above the Tg of the emulsion-polymerized polymer or the shell layer of the emulsion-polymerized polymer. When the Tg of the polymer obtained by emulsion polymerization is high,
A solvent may be added to the emulsion to lower the apparent Tg, and then coagulated by a liquid cross-linking method to coagulate. The solvent used at this time is not particularly limited, and examples thereof include aliphatic hydrocarbons such as hexane and heptane.

The emulsion-polymerized emulsion is coagulated by the above-described method, then filtered and dried to obtain a polymer powder (C). The drying temperature at this time is not particularly limited. T of shell layer of coalesced powder or polymer powder
It is preferred that the drying be carried out at a rate of not more than g.

The curing agent (D) used in the present invention is a component which is polymerized and cured when the (meth) acrylic SMC or BMC of the present invention is molded. The curing agent (D) is not particularly limited, and a polymerization initiator such as an organic peroxide and an azo compound can be used.

Specific examples of the curing agent (D) include, for example,
Lauroyl peroxide (10 hour half-life temperature = 62
° C), stearoyl peroxide (10-hour half-life temperature = 62 ° C), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (10-hour half-life temperature = 65 ° C), t- Hexylperoxy-2-ethylhexanoate (10-hour half-life temperature = 70 ° C.), t-butylperoxy-2-ethylhexanoate (10-hour half-life temperature = 72 ° C.), benzoyl peroxide (1
0 hour half-life temperature = 73 ° C.), di-t-butylperoxy-2-methylcyclohexane (10-hour half-life temperature =
83 ° C), 1,1-bis (t-hexylperoxy)-
3,3,5-trimethylcyclohexane (10-hour half-life temperature = 87 ° C.), 1,1-bis (t-hexylperoxy) cyclohexane (10-hour half-life temperature = 87 ° C.),
1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane (10-hour half-life temperature = 90
° C), 1,1-bis (t-butylperoxy) cyclohexane (10-hour half-life temperature = 91 ° C), 1,1-bis (t-butylperoxy) cyclododecane (10-hour half-life temperature = 95 ° C) ), T-hexylperoxyisopropyl carbonate (10 hour half-life temperature = 95 ° C.), t
-Butylperoxy-3,5,5-trimethylhexanoate (10-hour half-life temperature = 97 ° C.), t-butylperoxylaurate (10-hour half-life temperature = 98 ° C.), t
-Butyl peroxyisopropyl carbonate (10 hour half-life temperature = 99 ° C.), t-butyl peroxy-2-
Ethylhexyl carbonate (10 hour half-life temperature = 9
9 ° C.), t-hexylperoxybenzoate (10-hour half-life temperature = 99 ° C.), t-amylperoxybenzoate (10-hour half-life temperature = 100 ° C.), 2,2-bis (t-butylperoxy) Butane (10-hour half-life temperature = 103 ° C.), t-butylperoxybenzoate (10-hour half-life temperature = 104 ° C.), n-butyl-4,
Organic peroxides such as 4-bis (t-butylperoxy) valerate (10-hour half-life temperature = 105 ° C.), dicumyl peroxide (10-hour half-life temperature = 116 ° C.);
2,2'-azobis (2,4-dimethylvaleronitrile)
(10-hour half-life temperature = 51 ° C.), 2,2′-azobisisobutyronitrile (10-hour half-life temperature = 65 ° C.),
2,2'-azobis (2-methylbutyronitrile) (1
And azo compounds such as 1,1′-azobis (cyclohexane-1-carbonitrile) (10-hour half-life temperature = 88 ° C.).

These curing agents (D) are acrylic SM
Depending on the molding temperature at the time of molding C or BMC, it can be appropriately selected and used, and one type or two or more types having different 10-hour half-life temperatures may be used in combination.

The acrylic SMC or BMC of the present invention
Has the above components (A) to (D) as basic constituent components, and may further include a stone pattern material. As described above, by molding the acrylic SMC or BMC of the present invention containing a stone pattern material, it is possible to obtain a granite artificial marble having an unprecedented clear stone pattern and excellent design. .

The stone pattern material that can be used in the present invention includes:
One type of pattern material may be used, or two or more types of pattern materials having different colors may be used. In addition, this stone pattern material, inside the pattern material itself, one more type,
Alternatively, two or more types of grain pattern materials having different colors and particle sizes may be contained.

In the present invention, the content of the stone pattern material is not particularly limited, but may be (meth) acrylic SMC or BMC.
The amount is preferably in the range of 1 to 50% by mass of the total amount of MC. When the content of the stone pattern material is 1% by mass or more, a resin molded product having a stone pattern with good design properties tends to be obtained.
When the content is 0% by mass or less, the moldability of the (meth) acrylic SMC or BMC tends to be good.

The lower limit of the content of the stone pattern material is (meta)
In the total amount of the acrylic SMC or BMC, 3% by mass or more is more preferable, and 5% by mass or more is particularly preferable. The upper limit of the content is more preferably 30% by mass or less, and 2% by mass or less.
0 mass% or less is particularly preferred.

The material of the stone pattern material that can be used in the present invention is not particularly limited, and resin particles, resin particles containing an inorganic filler, and the like may be appropriately used. When resin particles are used as the stone pattern material, the type of the resin material constituting the resin particles is not particularly limited.

Specific examples of the resin material include acrylic resin, vinyl ester resin, unsaturated polyester resin, epoxy resin, saturated polyester resin, polycarbonate resin, polyolefin resin, polyamide resin, polystyrene resin, polyurethane resin, and melamine resin. ,
Phenol resin, polyvinyl chloride resin and the like can be mentioned, and among them, acrylic resin is preferable.

When the inorganic filler-containing resin particles are used as the stone pattern material, the type of the constituent resin material is not particularly limited, and for example, the above-described resin materials may be used. Further, the inorganic filler is not particularly limited, for example, aluminum hydroxide, silica, fused silica, calcium carbonate, barium sulfate, titanium oxide, glass powder and the like, among which aluminum hydroxide, silica, fused silica, At least one selected from calcium carbonate and glass powder is preferred.

The method for producing the stone pattern material usable in the present invention is not particularly limited, and examples thereof include a method of pulverizing a resin plate or a resin molded product containing an inorganic filler. The method of pulverization is not particularly limited, and examples thereof include pulverization using a crusher or the like. If necessary, the pulverized resin molded product may be classified for each particle size by a sieve and used.

The acrylic SMC or BMC of the present invention may further include a reinforcing material such as glass fiber or carbon fiber, a polymerization inhibitor, a coloring agent, a low shrinkage agent, if necessary, in addition to the stone pattern material. Various additives such as an internal mold release agent can be added.

Next, the (meth) acrylic SMC of the present invention
Alternatively, a method for manufacturing BMC will be described. In the present invention, the above-mentioned components (A) to (D) and, if desired, the stone pattern material and various additives are mixed and kneaded at the same time so that the temperature of the kneaded material is in the range of 10 to 60 ° C. .

When the temperature of the kneaded material is 10 ° C. or more, it tends to be possible to knead the components (A) to (D) simultaneously with mixing, and the temperature of the kneaded material is 60 ° C. or less. In such a case, the volatilization of the (meth) acrylic monomer component having a low boiling point tends to be suppressed. Under such a temperature condition, the (meth) acrylic SMC or B does not substantially change the component ratio of the constituent components at the time of preparation and after the kneaded material is obtained.
It is possible to produce MC.

The lower limit of the temperature of the kneaded product is more preferably at least 20 ° C., particularly preferably at least 30 ° C. Further, the upper limit is more preferably 55 ° C. or lower, particularly preferably 50 ° C. or lower.

The apparatus for kneading and mixing at the same time is not particularly limited, and a batch apparatus or a continuous apparatus can be used. For example, dispersers, mixers, double-armed kneaders, co-kneaders, rolls, extruders, kneading extruders and the like can be mentioned.

The (meth) acrylic resin molded article of the present invention can be obtained by curing the above-mentioned (meth) acrylic SMC or BMC.

The curing method is not particularly limited, but it is preferable to carry out heating and pressure curing.
Examples of the method include an injection molding method and a transfer molding method. The heating and pressure curing conditions for obtaining the (meth) acrylic resin molded product of the present invention are not particularly limited, but the heating temperature is preferably in the range of 50 to 150 ° C.

There is no particular limitation on the pressing pressure among the heating and pressing curing conditions, but it is preferably in the range of 1 to 20 MPa. When the pressurizing pressure is 1 MPa or more, the filling property of the acrylic SMC or BMC into the mold tends to be good, and the surface smoothness of the resin molded product tends to be good. And there is a tendency that a good appearance without forming is obtained. The lower limit of the pressure is more preferably 2 MPa or more, and the upper limit is 15 MPa.
The following is more preferred.

The curing time of the heat and pressure curing conditions is not particularly limited, but may be appropriately selected depending on the desired thickness of the resin molded product.

[0067]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples. All parts and percentages in the examples are based on mass.

Specific surface area: Measured by a nitrogen adsorption method using a surface area meter SA-6201 (manufactured by Horiba, Ltd.). Average particle diameter: Measured using a laser diffraction / scattering particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.).

Weight-average molecular weight: This is a value in terms of polystyrene by the GPC method, and was measured under the following conditions. Equipment: High-speed GPC equipment HLC-802 manufactured by Tosoh Corporation
0 column: 3 pieces of TSKgelGMHXL manufactured by Tosoh Corporation
Oven temperature: 38 ° C Eluent: tetrahydrofuran Sample concentration: 0.4% by mass Flow rate: 1 ml / min Injection volume: 0.1 ml Detector: RI (differential refractometer)

Glass transition temperature (° C.): When the polymer powder is a copolymer obtained by polymerizing n kinds of monomers, a homopolymer glass of the n kinds of monomer components is constituted. From the transition temperature (° C.), it was calculated by the following formula (I), and the decimal part was rounded off. As the glass transition temperature of the homopolymer, a value from "Polymer Data Handbook" edited by The Society of Polymer Science, Japan was used.

[0071]

(Equation 2)

Tg: glass transition temperature of copolymer (° C.) Tg _(i) : glass transition temperature of homopolymer of i component (° C.)
w _i : mass ratio of i component, Δw _i = 1

(Production Example of Polymer Powder (C-1)) A reaction vessel equipped with a cooling pipe, a thermometer, a stirrer, and a nitrogen introducing pipe was placed in a reaction vessel.
1150 parts of pure water, a special carboxylic acid type surfactant as a surfactant (trade name “Latemul ASK” manufactured by Kao Corporation)
5 parts, and 1 part of potassium persulfate as a polymerization initiator,
400 parts of methyl methacrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name "Acryester M") and 100 parts of ethyl acrylate (manufactured by Mitsubishi Chemical Corporation) are used as monomers, and n-octyl mercaptan 0.1 is used as a chain transfer agent.
Five parts were charged and the temperature was raised to 50 ° C. while stirring under a nitrogen atmosphere. After holding for 5 hours, the emulsion was cooled to terminate the emulsion polymerization to obtain an emulsion. The average particle size of the primary particles of the polymer of the obtained emulsion was 0.20 μm.
m. A container equipped with a thermometer, a stirrer, and a steam inlet tube was charged with 300 parts of pure water and 0.2 part of sulfuric acid. Next, while stirring this aqueous sulfuric acid solution, steam was introduced to the aqueous solution for 4 hours.
After the temperature was raised to 0 ° C., 150 parts of the above-mentioned emulsion was added, and the mixture was kept at 40 ° C. for 5 minutes to coagulate polymer particles. Next, after the temperature was raised to 65 ° C., n-heptane was added, and the mixture was kept at 65 ° C. for 5 minutes to aggregate the coagulated polymer particles. Thereafter, the temperature was gradually raised to volatilize n-heptane, and the temperature was raised to 95 ° C., held for 5 minutes to solidify, and the solidification was completed. The solidified polymer particles were filtered, washed, and dried to obtain a polymer powder (C-1). The specific surface area of the obtained polymer powder (C-1) is 0.5 m ² / g.
Having an average particle size of 150 μm and a weight average molecular weight of 5
It was 50,000. In addition, the calculated value of Tg according to the formula (I) is 71
° C.

(Production Example of Polymer Powder (C-2)) A reaction vessel equipped with a cooling pipe, a thermometer, a stirrer, and a nitrogen introducing pipe was placed in a reaction vessel.
1150 parts of pure water, a special carboxylic acid type surfactant as a surfactant (trade name “Latemul ASK” manufactured by Kao Corporation)
Five parts and 150 parts of methyl methacrylate as a monomer were charged, and the temperature was raised to 70 ° C. while stirring under a nitrogen atmosphere. There, potassium persulfate 1.25 as a polymerization initiator
Part. The external temperature was maintained at 70 ° C., and after confirming the polymerization exothermic peak, the temperature was further maintained for 120 minutes to polymerize the core layer. Next, a mixture consisting of 280 parts of methyl methacrylate and 70 parts of ethyl acrylate was added dropwise over 30 minutes, and after completion of the addition, the mixture was held for 90 minutes to polymerize the shell layer.
After cooling, the emulsion polymerization was completed to obtain an emulsion having a core / shell structure. The obtained emulsion was coagulated under the same conditions as in the production example of the polymer powder (C-1) to obtain a polymer powder (C-2). Obtained polymer powder (C-2)
Has a specific surface area of 0.5 m ² / g and an average particle size of 16
0 μm, and the weight average molecular weight was 780,000. The calculated value of Tg of the core layer according to the formula (I) is 105 ° C., the calculated value of Tg of the shell layer is 71 ° C., and the average value (calculated value) of Tg of the core layer and the shell layer is 81 ° C.

(Production Example of Polymer Powder (C-3)) In a reaction vessel equipped with a cooling pipe, a thermometer, a stirrer, a dropping device, and a nitrogen introduction pipe, 750 parts of pure water, and alkyldiphenyl ether sulfonic acid as a surfactant were used. Sodium (Kao Corporation)
And 4 parts of trade name “Perex SS-H”) and 1 part of potassium persulfate as a polymerization initiator, and the mixture was heated to 70 ° C. while stirring under a nitrogen atmosphere. A mixture of 500 parts of methyl methacrylate and 5 parts of a surfactant sodium dialkyl sulfosuccinate (trade name “Perex OT-P” manufactured by Kao Corporation) was added dropwise over 3 hours, and the mixture was held for 1 hour. Then raise the temperature to 80 ° C and
After holding for a time, the mixture was cooled to room temperature to terminate the emulsion polymerization, thereby obtaining an emulsion. Next, this emulsion was spray-dried using a spray dryer (L-8 type manufactured by Okawara Kakoki Co., Ltd.) at an inlet temperature / outlet temperature of 150 ° C./90° C. to obtain a methacrylic polymer powder (C- 3) was obtained.
The specific surface area of the obtained polymer powder (C-3) is 50 m ² /
g, the average particle diameter is 30 μm, and the weight average molecular weight is 6
It was 10,000. Further, the calculated value of Tg by the formula (I) is 10
5 ° C.

(Production Example of Polymer Powder (C-4)) A reaction vessel equipped with a cooling pipe, a thermometer, a stirrer, and a nitrogen inlet pipe was placed in a reaction vessel.
800 parts of pure water and polyvinyl alcohol (saponification degree 8
After dissolving 1 part of 8% and a polymerization degree of 1000) in 400 parts of methyl methacrylate, 0.8 part of azobisisobutyronitrile as a polymerization initiator and n-type as a chain transfer agent.
A solution in which 1.2 parts of dodecyl mercaptan was dissolved was added, and the mixture was heated to 80 ° C. for 1 hour while stirring at 300 rpm in a nitrogen atmosphere, and heated as it was for 2 hours. afterwards,
After heating to 90 ° C and heating for 2 hours, it was cooled to room temperature,
The suspension polymerization was completed. The obtained suspension is filtered,
After washing, it was dried with a hot air dryer at 50 ° C. to obtain a methacrylic polymer powder (C-4). The specific surface area of the obtained polymer powder (C-4) was 0.07 m ² / g, the average particle diameter was 350 μm, and the weight average molecular weight was 100,000. Further, the calculated value of Tg according to the formula (I) is 105 ° C.

(Production Example of Polymer Powder (C-5)) In a reaction vessel equipped with a cooling pipe, a thermometer, a stirrer, a dropping device, and a nitrogen introduction pipe, 925 parts of pure water, and alkyldiphenyl ether sulfonic acid as a surfactant were used. 5 parts of sodium and 1 part of potassium persulfate as a polymerization initiator were charged and heated to 70 ° C. while stirring under a nitrogen atmosphere. To this, a mixture of 350 parts of methyl methacrylate, 150 parts of n-butyl acrylate (manufactured by Mitsubishi Chemical Corporation), and 5 parts of sodium dialkyl sulfosuccinate surfactant was added dropwise over 3 hours, and then maintained for 1 hour. 80 ° C
After maintaining the temperature for 1 hour and cooling to room temperature, the emulsion polymerization was terminated to obtain an emulsion. Next, this emulsion was spray-dried (L-8 manufactured by Okawara Kakoki Co., Ltd.).
Inlet temperature / outlet temperature = 120 ° C./50° C.
Spray-drying with methacrylic polymer powder (C-
5) was obtained. The specific surface area of the obtained polymer powder (C-5) was 0.3 m ² / g, the average particle diameter was 30 μm, and the weight average molecular weight was 600,000. Also, T
g Calculated value is 43 ° C.

Example 1 As a (meth) acrylic monomer, 16 parts of methyl methacrylate (trade name “Acryester M” manufactured by Mitsubishi Rayon Co., Ltd.) and 1,3-butylene glycol dimethacrylate (Mitsubishi Rayon (Japan) Co., Ltd.
6 parts of trade name "Acryester BD"), aluminum hydroxide as inorganic filler (manufactured by Sumitomo Chemical Co., Ltd., trade name "C
WL-325J ") as polymer powder (C-
1) 17 parts, 0.6 part of 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane (trade name "Perhexa 3M", manufactured by NOF CORPORATION) as a curing agent,
0.01 parts of 2,6-di-t-butyl-4-methylphenol (manufactured by Sumitomo Chemical Co., Ltd., trade name "Sumilyzer BHT") as a polymerization inhibitor, and 0.15 parts of zinc stearate as an internal mold release agent Was charged into a batch type kneader (manufactured by Moriyama Seisakusho Co., Ltd., MS type double arm type kneader, model G30-10), and mixed and kneaded for 10 minutes to obtain methacrylic BMC. The temperature of the obtained methacrylic BMC was 25 ° C., and there was no stickiness immediately after kneading and the handleability was good.

When the composition of this methacrylic BMC was analyzed, methyl methacrylate / 1,3-butylene glycol dimethacrylate / polymer powder / aluminum hydroxide = 15.6 / 6.0 / 17.0 / 61.0 ( Mass ratio), and the ratio of methyl methacrylate in the methacrylic BMC to the charged methyl methacrylate is
15.6 / 16 = 0.975, and a methacrylic BMC almost as charged was obtained. Next, 700 g of the methacrylic BMC was charged into a 200 mm square plate-forming mold, and the upper mold temperature was 130 ° C., and the lower mold temperature was 11 mm.
The mixture was cured by heating and pressurizing at 5 ° C. and a pressure of 10 MPa for 10 minutes to obtain an acrylic artificial marble molded product having a thickness of 10 mm. The appearance of the obtained molded product was good.

Example 2 Kneading for 10 minutes in a batch kneader under the same conditions as in Example 1 except that (C-2) was used instead of the polymer powder (C-1). And methacrylic BMC. The obtained methacrylic BMC
Was 30 ° C., and there was no stickiness immediately after kneading, and the handleability was good. When the composition of this methacrylic BMC was analyzed, methyl methacrylate / 1,3-
Butylene glycol dimethacrylate / polymer powder / aluminum hydroxide = 15.2 / 6.0 / 17.0 / 6
1.0 (mass ratio), the ratio of methyl methacrylate in the methacrylic BMC to the charged methyl methacrylate was 15.2 / 16 = 0.95, and methacrylic BMC almost as charged could be obtained. Was.
Next, 700 g of the methacrylic BMC was filled into a 200 mm square plate-forming mold, heated and cured for 10 minutes under the conditions of an upper mold temperature of 130 ° C., a lower mold temperature of 115 ° C., and a pressure of 10 MPa. A 10 mm acrylic artificial marble molded product was obtained. The appearance of the obtained molded product was good.

[Comparative Example 1] Kneading was carried out for 10 minutes using a batch kneader under the same conditions as in Example 1 except that (C-3) was used instead of the polymer powder (C-1). And methacrylic BMC. The obtained methacrylic BMC
Had good tackiness without stickiness immediately after kneading, but its temperature had risen to 65 ° C. due to shear heat generation. When the composition of this methacrylic BMC was analyzed, methyl methacrylate / 1,3-butylene glycol dimethacrylate / polymer powder / aluminum hydroxide = 10.4 / 6.0 / 17.0 / 61.0 (mass ratio) And the ratio of methyl methacrylate in the methacrylic BMC to the charged methyl methacrylate is 10.
4/16 = 0.65, and 35% of the charged methyl methacrylate was volatilized.

[Comparative Example 2] Kneading was carried out for 10 minutes in a batch kneader under the same conditions as in Example 1 except that (C-4) was used instead of the polymer powder (C-1). The resulting mixture was not thickened, had stickiness, and was poor in handleability.

Comparative Example 3 The kneading was carried out for 10 minutes in a batch kneader under the same conditions as in Example 1 except that (C-5) was used instead of the polymer powder (C-1). The resulting kneaded material was thickened, but had a low ultimate viscosity, was sticky, and had poor handling properties.

Hereinafter, a comparative example will be described. Comparative Example 1 is an example in which the polymer powder (C-3) was used instead of the polymer powder (C) used in the present invention. Since the polymer powder (C-3) had a large specific surface area, the thickening rate was high, shear heat was generated, and the temperature of the kneaded product increased to 65 ° C. Therefore, the component ratio of the constituent components at the time of charging was not maintained, and the amount of methyl methacrylate in the obtained kneaded material was reduced by 35% as compared with the time of charging.

Comparative Example 2 is an example in which the polymer powder (C-4) was used in place of the polymer powder (C) used in the present invention. This polymer powder (C-4) had a low specific viscosity due to its small specific surface area, and was kneaded for 10 minutes, but did not thicken. Thus, the obtained kneaded material was sticky and poor in handleability.

Comparative Example 3 is an example in which the polymer powder (C-5) was used in place of the polymer powder (C) used in the present invention. This polymer powder (C-5) had a low Tg, so the thickening rate was low, the viscosity was low, and the handleability was poor.

[0087]

As described above, the present invention has been found to exhibit an appropriate rate of thickening by using a polymer powder having a specific specific surface area as a thickener. Mixing and kneading of the components can be performed simultaneously, and the component ratio of the components does not substantially change at the time of preparation and after obtaining the kneaded material, and there is no stickiness and good handleability (meta). Acrylic SMC or BMC
Is made possible.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/101 C08K 5/101 C08L 3/00 C08L 3/00 101/00 101/00 (72) Inventor Yuichiro Kishimoto 4-160 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi F-term in Mitsubishi Rayon Co., Ltd. Product Development Laboratory 4F071 AA33 AB23 AB25 AB26 AB28 AC08 AC12 AE02 AE17 AH03 BA01 BB03 BC07 BC09 4F072 AA08 AD09 AE01 AE06 AF01 AG03 AG04 AK04 AK14 AL17 4J002 BG021 DE136 DE146 DE236 DG046 DH046 DJ016 DJ036 DJ046 DJ056 DL006 EH077 EK008 EQ018 FD016 FD148 GL00

Claims (5)

[Claims] 1. A (meth) acrylic monomer or a (meth) acrylic syrup (A), an inorganic filler (B), a specific surface area of 0.25 to 0.95 m ² / g,
A (meth) acrylic SMC or BMC containing a polymer powder (C) having a glass transition temperature of 50 ° C. or higher and a curing agent (D). 2. The (meth) acrylic S according to claim 1, wherein the polymer powder (C) is a polymer powder obtained by pulverizing an emulsion produced by emulsion polymerization.
MC or BMC. 3. The (meth) acrylic SMC or BM according to claim 2, wherein the powdering method is solidification.
C. 4. A (meth) acrylic monomer or (meth) acrylic syrup (A), an inorganic filler (B), having a specific surface area of 0.25 to 0.95 m ² / g,
(Meth) acrylic type, wherein a polymer powder (C) having a glass transition temperature of 50 ° C. or more and a curing agent (D) are mixed and kneaded at the same time within a temperature range of 10 to 60 ° C. Manufacturing method of SMC or BMC. 5. A (meth) acrylic monomer or (meth) acrylic monomer
Acrylic syrup (A), inorganic filler (B), polymer powder (C) having a specific surface area in the range of 0.25 to 0.95 m ² / g and a glass transition temperature of 50 ° C. or higher,
A (meth) acrylic resin molded product obtained by curing a (meth) acrylic SMC or BMC containing a curing agent (D) with heat and pressure.