JP2000302882A - Production of acrylic bmc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively obtain optimum conditions capable of producing an acrylic BMC(bulk molding compound) at a high production speed. SOLUTION: An acrylic BMC is continuously produced by kneading (A) an acrylic monomer or an acrylic syrup, (B) an acrylic polymer, and (C) an inorganic filler in a kneader 9 of the continuous system under such temperature and time conditions that a kneading torque of not less than 1 N.m can be detected when an acrylic BMC having components (A), (B), and (C) as the constituting components is kneaded in a torque rheometer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an acrylic BMC (bulk molding compound) having excellent handleability and moldability with high productivity.

[0002]

2. Description of the Related Art Acrylic artificial marble in which an inorganic filler such as aluminum hydroxide is blended with an acrylic resin has various excellent functional properties such as excellent molded appearance, warm touch and weather resistance. It is widely used for counters such as kitchen counters, vanities, waterproof pans, and other architectural uses. These are generally filled in a mold with a so-called premix in which an inorganic filler is dispersed in an acrylic syrup composed of an acrylic monomer and an acrylic polymer having methyl methacrylate as a main component. It is manufactured by a casting method that cures and polymerizes at low temperatures.

However, since the acrylic syrup has a low boiling point, the curing temperature has to be lowered, and as a result, a long molding time is required, resulting in low productivity. Also,
The shape of the molded article is limited due to the problem of the filling property of the premix into the mold.

In order to improve these drawbacks, studies have been made on the production of acrylic artificial marble by heating and pressurizing an acrylic BMC obtained by thickening an acrylic premix with a thickening agent. Also, a method for producing the acrylic BMC has been conventionally studied. For example, in Japanese Patent Application Laid-Open No. 10-67906,
The present inventors have disclosed a continuous method for producing acrylic BMC using a continuous twin-screw kneading extruder, and have disclosed about 20 to
Acrylic BMC is manufactured at a production rate of 25 kg / h.

[0005] However, Japanese Patent Application Laid-Open No. 10-67906 does not describe specific conditions (temperature, etc.) for kneading, and in order to increase the production rate of acrylic BMC,
Simply increasing the feed rate of the material will result in insufficient thickening,
Acrylic BMC with high production speed (30kg / h or more)
Is difficult to manufacture.

[0006]

According to the present invention, a high production rate (30 kg / h or more) is obtained by utilizing the above-mentioned production method (Japanese Patent Laid-Open No. 10-67906) found by the present inventors.
However, it has been made to further improve the production conditions and the like so that the acrylic BMC can be produced stably. That is, an object of the present invention is to provide a production method for producing an acrylic BMC at a high production rate using a continuous kneader.

[0007]

Means for Solving the Problems The present inventors have studied to achieve the above object, and as a result, when producing an acrylic BMC, under the temperature and time conditions under which a kneading torque is detected in a specific amount or more. It has been found that by kneading, an acrylic BMC can be continuously produced at a high production rate, and the present invention has been completed. That is, the present invention
An acrylic monomer or an acrylic syrup (A), an acrylic polymer (B), and an inorganic filler (C), and optionally an acrylic BMC containing inorganic filler-containing resin particles (D) as constituents. A method for producing a composition, wherein the components (A) and (B) are kneaded under a temperature and time condition such that a kneading torque of 1 N · m or more is detected by the device when the constituent components are kneaded with a torque rheometer. A method for producing an acrylic BMC, comprising continuously kneading a component, a component (C), and optionally a component (D) in a continuous kneading machine.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

The acrylic monomer (A) used in the present invention is a component that imparts appropriate fluidity when molding the acrylic BMC according to the present invention. The 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.

For example, methyl (meth) acrylate, alkyl (meth) acrylate having an alkyl group having 2 to 20 carbon atoms, hydroxyalkyl (meth) acrylate having a hydroxyalkyl group having 1 to 20 carbon atoms, benzyl (meth) acrylate (Meth) acrylates having an ester group having an aromatic ring, such as (meth) acrylates having an ester group having a cyclohexane ring such as cyclohexyl (meth) acrylate, and ester groups having a bicyclo ring such as isobornyl (meth) acrylate. (Meth) acrylate, tricyclo [5.2.1.
(Meth) acrylate having an ester group having a tricyclo ring, such as [0 ^2,6 ] decanyl (meth) acrylate;
It has an ester group having a cyclic ether structure such as (meth) acrylate having an ester group having a fluorine atom such as 2,2,2-trifluoroethyl (meth) acrylate, glycidyl methacrylate, and tetrahydrofurfuryl (meth) acrylate ( (Meth) acrylate, (meth) acrylic acid, (meth) acrylate metal salt, (meth)
Acrylic monofunctional monomers such as acrylamide; and ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 3-butylene glycol di (meth) acrylate, 1,4-butylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) Acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, dimethylolethanedi (meth)
Acrylate, 1,1-dimethylolpropanedi (meth) acrylate, 2,2-dimethylolpropanedi (meth) acrylate, trimethylolethanetri (meth) acrylate, trimethylolpropanetri (meth) acrylate, tetramethylolmethanetri (Meth) acrylate, tetramethylolmethanedi (meth)
Acrylates, polyhydric esters of (meth) acrylic acid with polyhydric alcohols (for example, pentaerythritol, dipentaerythritol, etc.), acrylic polyfunctional monomers such as allyl (meth) acrylate, and the like are included.

These can be used alone or in combination of two or more if necessary. In addition, in this specification, "(meth) acrylate" means "acrylate and / or methacrylate."

In particular, when methyl methacrylate is contained in the component (A), the resulting molded article tends to have a depth peculiar to marble, and the appearance tends to be good, which is preferable. The content of methyl methacrylate is not particularly limited.
Preferably it is in the range of 40% by mass. The lower limit of the content is more preferably 5% by mass or more, and the upper limit is more preferably 30% by mass or less.

The component (A) includes, in addition to the acrylic monomer, aromatic vinyl such as styrene and divinylbenzene, vinyl acetate, (meth) acrylonitrile, vinyl chloride, maleic anhydride, maleic acid, and maleic acid. It may contain monomers such as esters, fumaric acid, fumaric acid esters, and triaryl isocyanurates.

In order to impart properties such as heat resistance, hot water resistance, strength, solvent resistance, and dimensional stability to a molded product obtained by molding the acrylic BMC according to the present invention, the component (A) must be added to the component (A). It is preferable to include a polyfunctional monomer.

In this case, the content of the polyfunctional monomer is not particularly limited, but is preferably in the range of 1 to 30% by mass based on the total amount of the acrylic BMC in order to obtain the above effect more effectively. The lower limit of the content is more preferably 3% by mass or more, and the upper limit is more preferably 25% by mass or less.

In particular, at least one of neopentyl glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate and tripropylene glycol di (meth) acrylate as polyfunctional monomers
The use of seeds is preferable because a molded article having extremely excellent surface gloss and hot water resistance can be obtained. In this case, at least one of neopentyl glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate is used in combination with another polyfunctional monomer. Is also good.

As the component (A), an acrylic monomer may be used as it is, or an acrylic syrup in which an acrylic polymer is dissolved in the acrylic monomer may be used. As the acrylic syrup, a polymer obtained by partially polymerizing an acrylic monomer in advance to form the polymer in the acrylic monomer may be used, or a polymer separately polymerized may be used as the acrylic monomer. A substance dissolved in a monomer may be used.

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 acrylic BMC according to the present invention. When the content is 5% by mass or more, the flowability of the acrylic BMC during molding tends to be good, and when the content is 95% by mass or less, the curing shrinkage ratio during molding tends to decrease. is there. The lower limit of the content is more preferably 10% by mass or more, and particularly preferably 15% by mass or more. About the upper limit of this content, 50 mass% or less is more preferable, and 40 mass% or less is especially preferable.

The acrylic polymer (B) used in the present invention is a thickener component that thickens the acrylic BMC to a sticky (bulk-like) material having good tackiness without stickiness. At least a part of the coalescence (B) is dissolved to increase the viscosity of the entire system, thereby acting as a thickener.

The constituents of the acrylic polymer (B) (monomers used for polymerization, etc.) include the above-mentioned acrylic monomers or the monofunctional monomers listed in the acrylic syrup (A). And / or a polyfunctional monomer can be used. If necessary, a homopolymer polymerized alone may be used, or a copolymer using two or more kinds may be used.

The form of the acrylic polymer (B) is not particularly limited, but is preferably a polymer powder. When the acrylic polymer (B) is a polymer powder, its handleability tends to be good, and the dissolution rate in the acrylic monomer or acrylic syrup (A) increases, The thickening rate tends to be faster, the thickening can be performed in a short time, and the productivity of acrylic BMC tends to be improved.

The polymer powder may be a non-crosslinked polymer powder or a crosslinked polymer powder, but is preferably a noncrosslinked polymer powder. When the polymer powder is a non-crosslinked polymer powder, the thickening rate tends to increase, the thickening can be performed in a short time, and the productivity of acrylic BMC tends to improve. In addition, the non-crosslinked polymer powder here means
This shows a polymer powder in which at least the surface layer is composed of a non-crosslinked polymer.

Further, the polymer powder is a polymer powder having a so-called core / shell structure composed of a core phase and a shell phase having different chemical compositions, structures or molecular weights of the polymers forming them. Can be used.
In this case, the core phase may be a non-crosslinked polymer or a crosslinked polymer, but the shell phase is preferably a noncrosslinked polymer.

Although the content of the acrylic polymer (B) is not particularly limited, it is 0.1 to 3 in the total amount of the acrylic BMC.
It is preferably within the range of 0% by mass. When this content is 0.1% by mass or more, a high thickening effect tends to be obtained,
Further, when the content is 30% by mass or less, the kneading property when producing an acrylic BMC tends to be good. The lower limit of the content is more preferably 1% by mass or more.
Particularly preferred is at least mass%. About an upper limit, 25 mass% or less is more preferable, and its 20 mass% or less is especially preferable.

The weight average molecular weight of the acrylic polymer (B) is not particularly limited, but the larger the weight average molecular weight, the higher the thickening effect and the better the hot water resistance of the molded article. It is preferable that it is above. The upper limit of the weight average molecular weight is not particularly limited, but is preferably 5,000,000 or less from the viewpoint of kneading properties of the acrylic BMC.

The weight average molecular weight referred to here is a value in terms of polystyrene by the GPC method, and is measured under the following conditions according to the range of the weight average molecular weight.

When the weight-average molecular weight is 100,000 or less; Apparatus: Tosoh Corporation, high-speed GPC apparatus HLC-812
0 column: TSKgelG2000HX, manufactured by Tosoh Corporation
L and TSKgelG4000HXL are connected in series. Oven temperature: 40 ° C. Eluent: tetrahydrofuran Sample concentration: 0.4% by mass Flow rate: 1 ml / min Injection volume: 0.1 ml Detector: RI (differential refractometer)

When the weight-average molecular weight is more than 100,000 and less than 1,000,000; Apparatus: Tosoh Corporation, high-speed GPC apparatus HLC-802
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)

When the weight average molecular weight is 1,000,000 or more; Apparatus: High speed GPC apparatus HLC-802 manufactured by Tosoh Corporation
0 column: Tosoh Corporation, TSKgel, GMHHR-
H (30) connected in series Oven temperature: 40 ° C. Eluent: tetrahydrofuran Sample concentration: 0.4% by mass Flow rate: 1 ml / min Injection volume: 0.1 ml Detector: RI (differential refractometer)

Since the weight average molecular weight of a polystyrene-based polymer is only up to 20,000,000, when measuring a polymer having a weight average molecular weight of 1,000,000 or more, a polystyrene calibration curve should be obtained with a weight average molecular weight of 5 billion. Extrapolated to the point and converted.

Further, as the acrylic polymer (B),
Two or more acrylic polymers differing in at least one of the composition, molecular weight and particle size may be used in combination. The method for producing the acrylic polymer (B) is not particularly limited, and may include bulk polymerization,
It can be produced by a known polymerization method such as solution polymerization, suspension polymerization, emulsion polymerization, and dispersion polymerization.

The inorganic filler (C) used in the present invention comprises:
It is a component that gives a marble-like deep texture and heat resistance to a molded product obtained by molding an acrylic BMC. The content of the inorganic filler (C) is not particularly limited, but is preferably in the range of 5 to 95% by mass based on the total amount of the acrylic BMC. This is because when the content of the component (C) is 5% by mass or more, the obtained molded article tends to have good texture and heat resistance,
Also, the shrinkage rate during curing tends to be low. On the other hand, when the content is 95% by mass or less, acrylic BMC
Tends to have good fluidity during molding. About the lower limit of this content, 20 mass% or more is more preferable,
Particularly preferred is 30% by mass or more. Moreover, about an upper limit, 80 mass% or less is preferable and 70 mass% or less is especially preferable.

The inorganic filler (C) 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. Further, these inorganic fillers may be subjected to a surface treatment such as a silane treatment. 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 preferred from the viewpoint of the texture of the obtained molded article.

The acrylic BMC of the present invention comprises the above-mentioned components (A) to (C) as basic constituents. The resin is further blended with inorganic filler-containing resin particles (D) and molded. Thus, a granite-like artificial marble having a stone pattern can be obtained.

The content of the inorganic filler-containing resin particles (D) is not particularly limited.
It is preferable to be within the range of 0.1 to 40% by mass. When the content is 0.1% by mass or more, a stone pattern with good design properties tends to be obtained, and when the content is 40% by mass or less, kneadability when producing an acrylic BMC is good. Tend to be. The lower limit of the content is more preferably 1% by mass or more, and particularly preferably 5% by mass or more.
The upper limit is more preferably 30% by mass or less.
0 mass% or less is particularly preferred.

The resin constituting the inorganic filler-containing resin particles (D) is not limited as long as it does not dissolve in methyl methacrylate, and examples thereof include a crosslinked acrylic resin, a crosslinked polyester resin, and a crosslinked polystyrene resin. A crosslinked acrylic resin is preferred because a molded article having a high affinity with the acrylic monomer or acrylic syrup (A) used in the present invention and having a beautiful appearance can be obtained. The crosslinked acrylic resin may contain a non-crosslinked acrylic polymer.

As the inorganic filler constituting the inorganic filler-containing resin particles (D), the inorganic fillers listed in the above-mentioned inorganic filler (D) can be used, and two or more kinds are used in combination. be able to. Further, different inorganic fillers may be used for the inorganic filler-containing resin particles (D) and the inorganic filler (C). The inorganic filler-containing resin particles (D) may contain a pigment as needed. In addition, as the inorganic filler-containing resin particles (D), one type may be used, or two or more types having different colors and particle sizes may be used in combination.

The method for producing the inorganic filler-containing resin particles (D) is not particularly limited. For example, a resin molded article containing an inorganic filler obtained by polymerization and curing by a hot press method, a casting method, or the like is pulverized. And classification by a sieve. Specifically, for example, a method of pulverizing and classifying an acrylic artificial marble is preferable.

The acrylic BMC according to the present invention may contain a curing agent, if necessary. The curing agent is not particularly limited, and bis (4-t-butylcyclohexyl)
Peroxydicarbonate (trade name “Parcadox 16”, manufactured by Kayaku Akzo Co., Ltd., 10-hour half-life temperature = 44)
° C), t-hexyl peroxypivalate (trade name “Perhexyl PV”, manufactured by NOF Corporation, 10-hour half-life temperature = 53 ° C), 3,5,5-trimethylhexanoyl peroxide (NOF Co., Ltd., trade name “Paloyl 355”, 10-hour half-life temperature = 59 ° C.), lauroyl peroxide (Nippon Oil & Fat Co., Ltd., trade name “Paloyl L”, 10-hour half-life temperature = 62 ° C.), t -Hexylperoxy-2-ethylhexanoate (trade name "Perhexyl O", manufactured by NOF Corporation, 10-hour half-life temperature = 70 ° C), t-butylperoxy-2-ethylhexanoate (NOF Co., Ltd., trade name “Perbutyl O”, 10-hour half-life temperature = 72 ° C.), benzoyl peroxide (trade name “Kadox B-CH50”, manufactured by Kayaku Akzo Co., Ltd.), 10 Time half-life temperature = 72 ° C),
t-butylperoxy-2-methylcyclohexane (trade name “Perhexa MC” manufactured by NOF Corporation, 10-hour half-life temperature = 83 ° C.), 1,1-bis (t-hexylperoxy) -3, 3,5-trimethylcyclohexane (trade name "Perhexa TMH", manufactured by NOF Corporation)
0 hour half-life temperature = 87 ° C.), 1,1-bis (t-hexylperoxy) cyclohexane (manufactured by NOF Corporation)
Product name "Perhexa HC", 10 hour half-life temperature = 87
° C), 1,1-bis (t-butylperoxy) -3,
3,5-trimethylcyclohexane (Nippon Oil & Fats Co., Ltd.)
Product name "Perhexa 3M", 10 hour half-life temperature =
90 ° C.), 1,1-bis (t-butylperoxy) cyclohexane (trade name “Perhexa C”, manufactured by NOF Corporation, 10 hour half-life temperature = 91 ° C.), 1,1-bis (t-butyl peroxy) (Butylperoxy) cyclododecane (trade name “Perhexa CD”, manufactured by NOF Corporation, 10 hour half-life temperature = 95 ° C.), t-hexylperoxyisopropyl carbonate (10-hour half-life temperature = 95 ° C.), t −
Amyl peroxy-3,5,5-trimethylhexanoate (trade name “Kayaester A” manufactured by Kayaku Akzo Co., Ltd.)
N, 10-hour half-life temperature = 95 ° C.), 1,6-bis (t-butylperoxycarbonyloxy) hexane (manufactured by Kayaku Akzo Co., Ltd., trade name “Kayaren 6-70”),
10-hour half-life temperature = 97 ° C.), t-butylperoxy laurate (trade name “Perbutyl L”, manufactured by NOF Corporation, 10-hour half-life temperature = 98 ° C.), t-butylperoxyisopropyl carbonate ( Manufactured by Nippon Yushi Co., Ltd.
Trade name “Perbutyl I”, 10 hour half-life temperature = 99
° C), t-butylperoxy-2-ethylhexyl carbonate (trade name “Perbutyl E”, manufactured by NOF Corporation, 10-hour half-life temperature = 99 ° C), t-hexylperoxybenzoate (NOF Corporation) (Trade name: Perhexyl Z, 10-hour half-life temperature = 99 ° C.), t
-Butylperoxy-3,5,5-trimethylhexanoate (trade name “Trigonox 42”, manufactured by Kayaku Akzo Co., Ltd., 10-hour half-life temperature = 100 ° C.), t-amylperoxybenzoate (Kyaku Akzo Co., Ltd., trade name “KD-1”, 10 hour half-life temperature = 100 ° C.), 2,
2-bis (t-butylperoxy) butane (manufactured by NOF Corporation, trade name “Perhexa 22”, 10-hour half-life temperature = 103 ° C.), t-butylperoxybenzoate (manufactured by NOF Corporation) Trade name “Perbutyl Z”, 10-hour half-life temperature = 104 ° C.), n-butyl-4,4-bis (t-butylperoxy) valerate (Nippon Oil & Fats Co., Ltd.)
Product name “Perhexa V”, 10 hour half-life temperature = 1
05 ° C), dicumyl peroxide (Nippon Oil & Fats Co., Ltd.)
Made, trade name "Park Mill D", 10 hour half-life temperature = 1
16 ° C.), 1,3-bis (t-butylperoxyisopropyl) benzoate (trade name “Percadox 14”, manufactured by Kayaku Akzo Co., Ltd., 10-hour half-life temperature = 121)
C)); 2,2'-azobis-2,4-
Dimethyl valeronitrile (trade name “ADVN” manufactured by Otsuka Chemical Co., Ltd., 10-hour half-life temperature = 52 ° C.), 1,
1′-azobis (1-acetoxy-1-phenylethane) (trade name “OTAZO-1” manufactured by Otsuka Chemical Co., Ltd.)
5, 10 hour half-life temperature = 61 ° C.), 2,2′-azobisisobutyronitrile (trade name “AIBN” manufactured by Otsuka Chemical Co., Ltd., 10 hour half-life temperature = 65 ° C.), 2,
2′-azobis-2-methylbutyronitrile (trade name “AMBN” manufactured by Otsuka Chemical Co., Ltd., 10-hour half-life temperature =
67 ° C.), dimethyl-2,2′-isobutyrate (trade name “MAIB”, manufactured by Otsuka Chemical Co., Ltd., 10-hour half-life temperature = 67 ° C.), 1,1′-azobis-1-cyclohexanecarbonitrile) ( Otsuka Chemical Co., Ltd., product name "AC
A curing agent such as an azo compound such as HN (10 hours half-life temperature = 87 ° C.) can be used.

These curing agents can be appropriately selected and used according to the molding temperature at the time of molding the acrylic BMC. However, from the viewpoint of the storage stability of the acrylic BMC, a 10-hour half-life temperature However, it is preferable to use a curing agent of 55 ° C. or higher. The 10-hour half-life temperature of the curing agent is more preferably at least 65 ° C, particularly preferably at least 75 ° C, most preferably at least 80 ° C. Also, the curing agent is
One or two or more different 10-hour half-life temperatures may be used in combination.

The content of the curing agent is not particularly limited.
The total amount of the acrylic BMC is preferably in the range of 0.01 to 10% by mass. When the content is 0.01% by mass or more, the curability of the acrylic BMC tends to be sufficient, and when the content is 10% by mass or less, the storage stability of the acrylic BMC tends to be good. .

The lower limit of the content is 0.05
It is more preferably at least 0.1% by mass, particularly preferably at least 0.1% by mass. The upper limit is more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

In addition to the above-mentioned curing agent, the acrylic BMC of the present invention may further include, if necessary, a reinforcing material such as glass fiber or carbon fiber, a polymerization inhibitor, a coloring agent, a low shrinkage agent, an internal release agent. Various additives such as a molding agent can be added.

In the present invention, the above-mentioned component (A)
When the component (B), the component (C) and, if desired, the component (D) are added thereto and the components are kneaded with a torque rheometer, the kneading torque of 1 N · m or more is detected by the device. Component (A), component (B), component (C) and, if desired, component (D) are kneaded in a continuous kneader under various temperature and time conditions to continuously produce acrylic BMC. I do. Here, the torque rheometer is a device that detects a kneading torque generated when kneading a resin or the like. For example, “Laboplast Mill” manufactured by Toyo Seiki Seisaku-sho, Ltd. or “Plasticorder” manufactured by Brabender , A device such as Haake's "Polylab System".

In the present invention, it is necessary to perform kneading in a continuous kneader under conditions of temperature and time such that a kneading torque of 1 Nm or more is detected by the torque rheometer. When kneading at a temperature and under conditions where the kneading torque is 1 N · m or more, thickening in a continuous kneader becomes possible, and a sufficiently thickened, non-sticky, acrylic excellent in handleability. BMC can be continuously discharged from a continuous kneader. If the kneading torque is less than 1 N · m, the acrylic BMC discharged from the continuous kneader does not increase in viscosity, and it is difficult to continuously obtain thickened acrylic BMC.

The lower limit of the kneading torque is 3N
M or more is preferable, and 5 Nm or more is more preferable. The upper limit value of the kneading torque is not particularly limited, but is preferably 200 N · m or less, more preferably 100 N · m or less. The kneading torque depends on the composition (components) of the acrylic BMC, the kneading temperature, and the kneading time. Therefore, the kneading temperature and the kneading time may be set according to the composition of the acrylic BMC so that a kneading torque of 1 N · m or more is detected when the acrylic BMC is continuously manufactured.

In the present invention, the kneading temperature is not particularly limited, and may be selected according to the composition of the acrylic BMC and the kneading time so that a kneading torque of 1 Nm or more is detected as described above. , 0 to 100 ° C. When the kneading temperature is within this range, the kneading properties tend to be good. The lower limit of the kneading temperature is more preferably at least 10 ° C, particularly preferably at least 20 ° C. Moreover, about an upper limit, 95 degrees C or less is more preferable, and 90 degrees C or less is especially preferable. The kneading time is also not particularly limited, and may be selected according to the composition of the acrylic BMC and the kneading temperature so that a kneading torque of 1 Nm or more is detected as described above.

In the present invention, kneading is performed under the temperature and time conditions under which a kneading torque of 1 N · m or more is detected by a torque rheometer, so that the acrylic B
MC can be continuously produced at a high production rate of 30 kg / h or more. The lower limit of the production rate of the acrylic BMC is more preferably 50 kg / h or more, and 100 kg / h.
It is preferable that it is above.

In the present invention, the torque rheometer is used.
The kneading torque of 1 Nm or more
Continuous mixing by kneading under temperature and time conditions
The production efficiency of the kneader can be increased. Where
Continuous kneader production efficiency refers to the production speed of acrylic BMC.
Degree (kg / h) is the square of the screw diameter (mm)²) And su
Divided by the number of screws and the number of screws
The diameter is the outermost diameter of the screw. This series
The production efficiency of the kneader is 0.01 kg / h · mm²Less than
Above is preferable, and 0.015 kg / h · mm²That's all
More preferably, 0.02 kg / h-mm ²Above is particularly good
Good.

In the present invention, the apparatus for continuously producing an acrylic BMC is not particularly limited, and has a kneading function and an extruding function inside, and continuously supplies raw materials to perform kneading inside the apparatus. Any known apparatus may be used as long as the apparatus continuously extrudes the kneaded material.
For example, a single-screw extruder, a twin-screw extruder, a twin-screw kneading extruder, a co-kneader and the like can be mentioned. Among these continuous kneading machines, a twin-screw kneading extruder is preferable, and for example, a KRC kneader manufactured by Kurimoto Ironworks Co., Ltd. can be mentioned.

In the present invention, the acrylic BMC obtained by kneading and thickening each of the above-mentioned components may be directly extruded into a cylindrical shape from the end of the continuous kneader. A die may be attached, and it may be continuously shaped into a predetermined shape and extruded.

Next, an embodiment of the method for producing an acrylic BMC of the present invention will be described with reference to schematic diagrams.

Using an apparatus shown in FIG. 1, an acrylic BMC
Out of the constituent components, the liquid component is put into the tank 1. The liquid components used here include a liquid sending pump 3 and a liquid sending pipe 4.
What is necessary is just to pass through. It is preferable that the tank 1, the liquid feed pump 3, and the liquid feed pipe 4 be made of a material whose liquid contact portion is not chemically attacked by the liquid component and / or a material that does not deteriorate the liquid component. Further, the liquid feed pump 3 only needs to have a constant supply performance as typified by, for example, a gear pump or a snake pump, and is preferably selected in consideration of physical properties such as viscosity of a liquid component. Further, depending on the type of the liquid component, another tank 1, a liquid sending pump 3,
A combination of the liquid feeding pipes 4 may be further added.

On the other hand, a powdery component of the constituent components of the acrylic BMC is charged into the container 5. The powdery component used here may be any component that passes through the fixed-quantity feeder 6 and the pipe 7. The container 5 is chemically formed by a powdery component,
It is preferable to use a material that is not physically affected and / or a material that does not alter the powdery components. Further, a combination of another container 5, a fixed-quantity feeder 6, and a pipe 7 may be further added according to the type of the powder component.

The fixed-quantity feeder 6 is, for example, like a screw feeder, and may have any such powder transfer capability. It is preferable that the ratio (mass ratio) between the supply amount of the fixed-quantity feeder 6 and the supply amount of the liquid sending pump 3 is as constant as possible. Therefore, it is preferable to control the amount of the liquid component and the powdery component to be fed into the hopper 8 while always weighing the mass. As a control method, for example, a method of measuring the mass of the tank 1 and the container 5 and other known methods can be used.

The pipe 7 is for charging the powdery component to the hopper 8. The liquid component and the powdery component supplied to the hopper 8 are supplied to a continuous kneader 9. The supplied liquid component and powdery component are kneaded by the continuous kneader 9 and, at the same time, are thickened to form the continuous kneader 9.
When it is extruded from the tip, it is an acrylic BMC (mochi) having good stickiness without stickiness.

The direction in which the acrylic BMC (mochi) is extruded is not particularly limited, and may be extruded from the front of the tip of the continuous kneader 9 or from below the tip. Extrusion die 10 is a continuous kneader 9
Is installed in front of or below the front end of the, and regulates the cross-sectional shape of the continuously extruded acrylic BMC (mochi). Acrylic BM thickened in continuous kneader 9
C (rice cake) is formed into a predetermined shape by being extruded from the extrusion die 10.

This shaped article is cut by the cutter 11 into a predetermined length. The cutter 11 may be, for example, a commonly used blade such as a guillotine cutter, and is not limited to this as long as it has an equivalent function. Further, the cutting direction is not particularly limited, and may be freely selected depending on the intended use, such as up and down, left and right, and parallel to the extrusion direction.

FIG. 2 is a schematic view showing an embodiment of an acrylic BMC formed into a sheet. FIG.
In the equation, P indicates length, Q indicates thickness, and R indicates width. P, Q, and R may be appropriately adjusted to desired dimensions. Immediately after the acrylic BMC molded product is obtained, it may be transferred to a molding die and molded. Further, the acrylic BMC shaped material may be conveyed on a conveyor 12 after being discharged from an extrusion die 10 as shown in FIG.

In the case where it takes time to form an acrylic BMC shaped product, it is preferable to cover the upper and lower portions with cover films 13 and 14 and to seal them, as shown in FIG. The cover films 13 and 14 are made of acrylic B
It is preferable to use those having gas barrier properties with respect to the monomers and the like contained in the MC imprint.

Examples of the film having a gas barrier property include polyolefin films such as polyethylene and polypropylene, polyamide films, polyester films, cellophane, poval films, ethylene-polyvinyl alcohol copolymer films, vinyl chloride-vinylidene chloride copolymer films. And the like. Further, the cover film may be a laminate film in which two or more layers of films are laminated. The method for sealing the film is not particularly limited, and examples thereof include a method of fusing the upper and lower cover films by heat fusion or the like.

When the acrylic BMC molded product sealed with the cover films 13 and 14 is transported, it is preferable to store it in a container or the like in order to maintain the molded shape.

The acrylic BMC of the present invention can be cured by heating and pressure to obtain an acrylic artificial marble. Specific examples of the heating and pressurizing curing include a press molding method, an injection molding method, and an extrusion molding method, but are not particularly limited.

When acrylic artificial marble is obtained using the acrylic BMC of the present invention, the heating temperature is not particularly limited, but is preferably in the range of 80 to 150 ° C. When the heating temperature is 80 ° C. or higher, the curing time can be shortened, and the productivity tends to increase. When the heating temperature is 150 ° C. or lower, the appearance of the obtained molded article tends to be good.
The lower limit of the heating temperature is more preferably 85 ° C or higher, and the upper limit is more preferably 140 ° C or lower. Further, the upper mold and the lower mold may be heated with a temperature difference within this temperature range.

The pressurizing pressure is not particularly limited.
It is preferably in the range of ２０20 MPa. Pressurizing pressure 1MPa
In the above case, the filling property of the acrylic BMC into the mold tends to be good, and when it is 20 MPa or less, a good molded appearance tends to be obtained. The lower limit of the applied pressure is more preferably 2 MPa or more, and the upper limit is more preferably 15 MPa or less. The molding time may be appropriately selected depending on the thickness of the molded product.

[0066]

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

<Physical Properties of Polymer Powder> Average particle diameter: Measured using a laser diffraction / scattering particle size distribution analyzer (LA-910, Horiba, Ltd.). -Weight average molecular weight: It is a value in terms of polystyrene by the GPC method, and is measured under the following conditions depending on the range of the weight average molecular weight.

When the weight average molecular weight is 100,000 or less; Apparatus: Tosoh Corporation, high-speed GPC apparatus HLC-812
0 column: TSKgelG2000HX, manufactured by Tosoh Corporation
L and TSKgelG4000HXL are connected in series. Oven temperature: 40 ° C. Eluent: tetrahydrofuran Sample concentration: 0.4% by mass Flow rate: 1 ml / min Injection volume: 0.1 ml Detector: RI (differential refractometer)

When the weight average molecular weight is more than 100,000 and less than 1,000,000: Apparatus: High-speed GPC apparatus 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)

When the weight average molecular weight is 1,000,000 or more; Apparatus: HLC-802, a high-speed GPC apparatus manufactured by Tosoh Corporation
0 column: Tosoh Corporation, TSKgel, GMHHR-
H (30) connected in series Oven temperature: 40 ° C. Eluent: tetrahydrofuran Sample concentration: 0.4% by mass Flow rate: 1 ml / min Injection volume: 0.1 ml Detector: RI (differential refractometer)

Since the polystyrene-based polymer has a weight average molecular weight of only up to 20,000,000, when a polymer having a weight average molecular weight of 1,000,000 or more is measured, the polystyrene calibration curve is determined using a polystyrene calibration curve having a weight average molecular weight of 5 billion. Extrapolated to the point and converted.

<Measurement of Kneading Torque> Kneading was performed by changing the kneading temperature under the following conditions using a Labo Plastomill (C model: 50C150) manufactured by Toyo Seiki Seisakusho as a torque rheometer. Was measured. Mixer: R-60 type roller mixer Number of revolutions: 30 rpm Material filling amount: 75 g

(Production Example of Polymer Powder (B-1)) 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. The average particle size of the primary particles of the polymer of the obtained emulsion was 0.10 μm.

Next, this emulsion was sprayed with a spray dryer (L-8 type, manufactured by Okawara Kakoki Co., Ltd.) to obtain an inlet temperature /
A spray drying treatment was performed at an outlet temperature of 150 ° C / 90 ° C to obtain a polymer powder (B-1). The obtained polymer powder (B-
The average particle size of 1) was 30 μm, and the weight average molecular weight was 600,000.

Example 1 As acrylic monomers (A), 6.5 parts of methyl methacrylate, 6.5 parts of isobornyl methacrylate, 10.4 parts of neopentyl glycol dimethacrylate, and 2,6-di -T-butyl-
23. Mixture consisting of 0.01 part of 4-methylphenol
41 parts, 15.6 parts of polymer powder (B-1) as an acrylic polymer (B), and aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd., trade name "CWL-") as an inorganic filler (C).
325J ") was charged into a Labo Plastomill mixer manufactured by Toyo Seiki Seisaku-sho, Ltd., and kneaded at 40 ° C for 45 seconds. A kneading torque of 39.2 N · m was detected.

Separately, as the acrylic monomer (A), 6.5 parts of methyl methacrylate, 6.5 parts of isobornyl methacrylate, 10.4 parts of neopentyl glycol dimethacrylate, and 2,6-di-t- As a curing agent, t-amyl peroxy-3,5,5-trimethylhexanoate (trade name “Kayaester AN” manufactured by Kayaku Akzo Co., Ltd.) was added to a mixture consisting of 0.01 part of butyl-4-methylphenol. 0.6 hours of premix and dissolution was charged into tank 1A, and 10 hours half-life temperature = 95 ° C.
Continuous twin-screw kneading extruder 9 (S-2 type KRC manufactured by Kurimoto Iron Works Co., Ltd.) with snake pump 3A manufactured by Hyojin Equipment Co., Ltd.
Kneader, screw diameter = 50 mm, L / D = 13.
It was continuously charged into the hopper 8 attached to 7).

As the acrylic polymer (B), the polymer powder (B-1) was charged in a SUS container 5B attached to a screw feeder 6B made by Kuma Engineering, and a hopper attached to a continuous twin-screw kneading extruder 9. 8 were continuously charged. As an inorganic filler (C), aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd., trade name "CWL-325J") is charged into a SUS container 5C attached to a screw feeder 6C made by Kuma Engineering, and is continuously twin-screw kneaded. It was continuously charged into the hopper 8 attached to the extruder 9.

A heating medium controlled at 40 ° C. was passed through the jacket of the barrel of the continuous twin-screw extruder 9.
At this time, so that the average residence time of the material in the continuous twin-screw kneading extruder of acrylic BMC is about 45 seconds,
The component (A) was added at a rate of 517 g / min, the component (B) was added at a rate of 336 g / min, and the component (C) was added at 1,314 g / min.
Each component was charged into a continuous twin-screw kneading extruder at a charging speed of 1 minute.

The acrylic BMC is continuously produced by the above-described method, and a sheet-shaped acrylic BMC having a thickness of 20 mm is supplied from the die 10 attached below the end of the continuous twin-screw kneading extruder at 130 kg / h. Continuously obtained at a production rate of. At this time, the production efficiency of the acrylic BMC was 0.0
It was 26 kg / h · mm ² . The obtained sheet-shaped acrylic BMC was thickened immediately after being discharged from the continuous twin-screw kneading extruder, had no stickiness, and had good handleability.

Next, the obtained acrylic BMC was
g 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 0 mm acrylic artificial marble flat plate was obtained. The resulting artificial marble had a high surface gloss and an extremely good appearance.

Comparative Example 1 The same composition as in Example 1 was used.
When kneading was performed at 20 ° C. for 20 seconds using a Labo Plastomill mixer manufactured by Toyo Seiki Seisakusho with changing the temperature and time, only a kneading torque of 0.5 N · m was detected.

Separately, in the same manner as in Example 1, each component was charged into a continuous twin-screw kneading extruder to continuously knead the acrylic BMC. However, the feeding rate of the component (A) was set to 1193 g / min so that the average residence time of the material in the continuous twin-screw kneading extruder was about 20 seconds.
The feeding speed of the component (B) was changed to 775.5 g / min, the feeding speed of the component (C) was changed to 3031.5 g / min, and the temperature of the heat medium passed through the jacket of the barrel of the continuous twin-screw extruder was changed. Was changed to 20 ° C.

The kneading of the acrylic BMC was carried out continuously by the above-mentioned method. However, the ejected matter ejected from the extrusion die 10 attached below the end of the continuous twin-screw kneading extruder was thickened. It was in a sticky, semi-liquid state and was not in the form of rice cakes.

[0084]

As is evident from the above examples, in the production of acrylic BMC, acrylic BM
When the components of C are kneaded with a torque rheometer, 1N
By kneading the constituents in a continuous kneader under conditions of temperature and time at which a kneading torque of m or more is detected, it becomes possible to produce an acrylic BMC at a high production rate. Moreover, the acrylic artificial marble produced using the acrylic BMC obtained by the production method of the present invention has an excellent appearance and is industrially very useful.

[Brief description of the drawings]

FIG. 1 schematically shows a continuous twin-screw kneader used in the present invention.

FIG. 2 is a schematic view showing one embodiment of an acrylic BMC formed into a sheet by the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank 3 Liquid-feed pump 4 Liquid-feed pipe 5 Container 6 Constant-quantity feeder 7 Piping 8 Hopper 9 Continuous twin-screw kneader 10 Extrusion die 11 Cutter 12 Conveyor 13 Upper cover film 14 Lower cover film P Length Q thickness R width

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuichiro Kishimoto 4-160 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi F-term in Mitsubishi Rayon Co., Ltd. Product Development Laboratory (reference) 4F072 AA07 AD05 AD09 AD38 AE02 AE09 AF02 AF03 AF04 AF06 AG04 AG14 AJ21 AK14 AL17 4J002 BC013 BG003 BG01W BG04W BG05W BG06W BG07W CD19W CF003 CH05X DE137 DE147 DE237 DG047 DH047 DJ017 DJ037 DJ047 DJ057 DL007 EF046 EH076 EL036 EL066 EP016 FB097 FD077 FB097 FD077

Claims (5)

[Claims] 1. A method for producing an acrylic BMC comprising an acrylic monomer or an acrylic syrup (A), an acrylic polymer (B), and an inorganic filler (C) as components. When the components are kneaded with a torque rheometer, under the temperature and time conditions such that the kneading torque of 1 N · m or more is detected by the device, the component (A)
Acrylic B characterized by being continuously manufactured by kneading the components (B) and (C) in a continuous kneader.
Manufacturing method of MC. 2. The method for producing an acrylic BMC according to claim 1, wherein the inorganic filler-containing resin particles (D) are further used as a component together with the components (A) to (C). 3. The method for producing an acrylic BMC according to claim 1, wherein the acrylic polymer (B) is a polymer powder. 4. The production rate of acrylic BMC is 30 kg.
/ H or more, the method for producing acrylic BMC according to claim 1 or 2, wherein: 5. The production efficiency of acrylic BMC is 0.01.
The method for producing an acrylic BMC according to claim 1 or ^{2, wherein the} weight is not less than kg / h · mm2.