JPH10218912A - Manufacture of resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and effective manufacturing method of a resin composition requiring no aging process and fully improved in productivity, especially a manufacturing method of the resin composition usable as a molding material of an artificial marble. SOLUTION: This manufacturing method of a resin composition comprises putting a monomer component mainly comprising a methacrylate, a methacrylate polymer, and an inorganic filler into a continuous twin-screw kneader and kneading at a temp of 65-120 deg.C to obtain a slurry-like or clay-like substance, then mixing a curing agent into the obtd. slurry-like or clay-like substance during or after cooling, and the monomer component mainly comprising a methacrylate is put into the continuous twin-screw kneader in some separate doses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a resin composition, and more particularly, to a method for producing a resin composition which can be used as a molding material for artificial marble, without the need for an aging step. The present invention relates to a method suitable for inexpensive production.

[0002]

2. Description of the Related Art Acrylic artificial marble is used for countertops, kitchen tops, vanities, flooring materials, wall materials, partition boards, etc., taking advantage of the excellent beauty and weather resistance of acrylic resin. It is used. As a method for producing an acrylic artificial marble, for example, Japanese Patent Publication No. 50-2258
There is known a cast molding method as proposed in Japanese Patent Application Laid-Open No. 6-64. Generally, the casting method involves pre-polymerizing methacrylic acid esters by about 10 to 30%, or mixing and mixing an inorganic filler into a so-called syrup in which a methacrylic acid ester polymer is dissolved in methacrylic acid esters. A method of injecting the mixture into a gap in a mold, and then curing the mixture under normal pressure to obtain an artificial marble product. However, there is no easy way to adjust the syrup,
This is the reason why the productivity of the casting method is lowered. That is, in the method of pre-polymerizing methacrylic acid esters, equipment and steps for pre-polymerization are required, and it is essentially difficult to adjust the polymerization rate because the polymerization is stopped in the middle of the method. There is a problem that it is difficult to easily produce syrup with good reproducibility. Further, the method of mixing and dissolving a methacrylate polymer in methacrylates has a problem that it takes a long time to dissolve.

As one method for avoiding such a problem, for example, a press molding method as proposed in Japanese Patent Publication No. 5-13899 has been studied. In this method, a monomer containing 20% by weight or more of a polyfunctional (meth) acrylate, which is an essential component, a methacrylic acid-based resin powder, a curing agent, an inorganic filler, and the like are kneaded at room temperature or at a temperature lower than the curing temperature. -A clay-like or solid molding material obtained by aging is molded and cured by heating under pressure. However, according to this method, although a considerable improvement in productivity is achieved as compared with the conventional casting method or press molding method, kneading is performed at room temperature or at a low temperature lower than the curing temperature because a kneading agent is added and kneading is performed. However, there is a problem that the productivity is still low because the aging process is required, and the mixing of the components cannot be sufficiently performed to increase the productivity.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a simple and efficient production of a resin composition in which productivity is sufficiently improved without the need for an aging step. It is an object of the present invention to provide a method for producing the resin composition, which can be used as a molding material for artificial marble and the like.

[0005]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies on a method for producing a resin composition that can be used as a molding material for artificial marble, and as a result, divided the monomer component. By adding and kneading the resin composition components excluding the curing agent with a continuous twin-screw kneader, a slurry-like molding material suitable for a casting method or a clay-like material having shape stability suitable for a press molding method The present inventors have found a method for easily producing the molding material of the present invention, and have completed the present invention.

That is, the gist of the present invention is as follows.
A monomer mainly composed of methacrylic acid ester, a methacrylic acid ester-based polymer and an inorganic filler are charged into a continuous twin-screw kneader, and kneaded at a temperature of 65 to 120 ° C to obtain a slurry or a clay-like material. A method for producing a resin composition by mixing a curing agent after cooling or during the cooling process to the obtained slurry or clay-like material, and comprising a monomer mainly comprising methacrylic acid ester In a continuous twin-screw kneader.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The methacrylate-based monomer used in the present invention refers to a methacrylate alone or a monomer mixture of methacrylate-based monomer and another unsaturated monomer copolymerizable therewith. It is desirable that the content of methacrylic acid ester is 50% by weight or more, preferably 70% by weight or more.

[0008] Methacrylic acid esters include those having 5 carbon atoms.
Methacrylates of about 18 to 18 are preferably used, and specific examples include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, and the like. . These are used alone or in combination of two or more. Among them, methyl methacrylate is particularly preferably used.

The other unsaturated monomer copolymerizable with the methacrylic acid ester is not particularly limited.
For example, acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, and lauryl acrylate; aromatic vinyl compounds such as styrene and α-methylstyrene; acrylonitrile, methacrylonitrile And unsaturated monomers such as acrylamide, vinyl acetate, vinyl chloride, acrylic acid, and methacrylic acid; and various monomers such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, and trimethylolpropane trimethacrylate. Functional unsaturated monomers and the like. One or more of these monomers may be used.

The methacrylic acid ester polymer used in the present invention can be used without particular limitation as long as it is a methacrylic acid ester polymer which is soluble in the above-mentioned monomer mainly composed of methacrylic acid ester. Preferred examples include those obtained by polymerizing the above-mentioned methacrylic acid ester-based monomers, or those obtained by polymerizing one or more of these monomers and other polymerizable monomers. be able to.

As the methacrylate-based polymer, a polymer obtained by polymerizing the above-mentioned methacrylate-based monomer by an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method or the like is usually used. The methacrylic acid ester-based polymer obtained by such a polymerization method is preferably in the form of particles from the viewpoint of mixing solubility with the monomer, and has a particle diameter of a size that can be used for kneading described below. Although it is not particularly limited as long as it is one, it is usually 5 mm or less, more preferably about 0.1 to 2 mm. The methacrylic acid ester is usually in the form of beads, pellets, pulverized powder, or the like, and is preferably in the form of beads from the viewpoint of solubility, handleability, and the like. The average molecular weight of the methacrylic acid ester-based polymer is that which can be dissolved in the monomer,
Usually, the range is from 50,000 to 600,000, preferably from 70,000 to 300,000, more preferably from 100,000 to 200,000. The mixing ratio of the methacrylate polymer is usually 5 to 400 parts by weight per 100 parts by weight of the monomer mainly composed of methacrylate.
Parts by weight, preferably 10 to 300 parts by weight. Also,
A part of the methacrylate polymer can be used in place of, for example, an acrylic partially crosslinked gel polymer whose production method is described in JP-A-60-202128.

The inorganic filler used in the present invention includes, for example, aluminum hydroxide, magnesium hydroxide, alumina, magnesium oxide, calcium carbonate, silica, mica, glass beads and the like. There is no particular limitation unless it impairs. Among these inorganic fillers, aluminum hydroxide, magnesium hydroxide, silica, and glass beads are preferred from the viewpoints of high quality, stain resistance, and processing performance required for acrylic artificial marble and the like. Aluminum is preferably used. The particle size of the inorganic filler is usually 0.1 to 100 μm, more preferably 1 to 30 μm. Inorganic fillers that have been surface-treated, such as silane treatment, are also preferably used. The mixing ratio of the inorganic filler is usually 50 to 500 parts by weight, preferably 1 to 100 parts by weight of the monomer mainly composed of methacrylic acid ester.
It is 00 to 400 parts by weight.

The curing agent used in the present invention is not particularly restricted but includes, for example, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, bis (4-t-butylcyclohexyl) dicarbonate, which are usually used in radical polymerization. Organic peroxides such as 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane; azobisisobutyronitrile, 2,2-
An azo compound such as azobis (2,4-dimethylvaleronitrile) is used. One or two of these curing agents may be used.
Used in more than species. The mixing ratio of the curing agent is based on 100 parts by weight of a monomer mainly composed of methacrylic acid ester.
Usually 0.001 to 10 parts by weight, preferably 0.005 to 10 parts by weight
7 parts by weight.

In the method of the present invention, it is necessary to divide a monomer mainly composed of methacrylic acid ester into a continuous twin-screw kneader and feed it. By dividing and adding, the properties of a low-viscosity slurry having poor kneading efficiency, which is initially generated during batch addition, can be changed to properties having higher viscosity, and the kneading efficiency can be increased to improve productivity. As a method of dividing and charging, it is desirable that the charged raw material has a hardness such that the barrel filling rate of the continuous twin-screw kneader becomes 40% or more, and is divided and charged so that it can be sent out, mixed and kneaded. The number of divisions, the number of supply positions, and the supply amount at each supply position are not particularly limited. For example, with respect to 100 parts by weight of the mixture of the methacrylate-based polymer and the inorganic filler, 5 to 100 parts by weight of a monomer mainly composed of methacrylate is first added, and then the remaining methacrylate is added. Once or 2 times as the main monomer
It is possible to take a method of adding in multiple portions.

As a continuous twin-screw kneader, raw materials are continuously fed into a kneading section by a feed screw section arranged in a raw material supply section, and are kneaded in a kneading section in which a rotor or a kneading desk is arranged. Is continuously discharged, and a twin-screw kneader, a container kneader or the like is preferably employed. These continuous twin-screw kneaders are preferably those in which the kneading degree can be freely adjusted by changing the combination of a screw, a rotor, a kneading desk, etc., and also correspond to a kneading part in terms of kneading properties and the like. It is preferable that the L / D of the portion to be formed is about 8 to 50. The meshing of the two shafts of the continuous twin-screw kneader may be either a non-meshing type or a meshing type, and the rotation direction of the two shafts may be either a co-rotating type or a different-direction rotating type. By using a continuous twin-screw kneader, the time required for dissolving and mixing the above raw materials is usually within 10 minutes, preferably 2 to
It can be about 5 minutes.

In the method of the present invention, a monomer mainly composed of the above-mentioned methacrylate is used in a continuous twin-screw kneader.
The methacrylate polymer and the inorganic filler are continuously charged, and the temperature is 65 to 120 ° C, preferably 70 to 120 ° C.
It is necessary to perform kneading at a temperature of 100 ° C. If the temperature is lower than 65 ° C., the kneading of the resin composition components excluding the curing agent is not sufficient, and the methacrylic acid ester-based polymer is not completely dissolved, which requires an aging time, which is not preferable. The short time aimed at by the present invention, ie, within 10 minutes,
It is necessary to knead at a temperature of 65 ° C. or higher in order to complete the dissolution / mixing in preferably about 2 to 5 minutes.
On the other hand, kneading at a temperature exceeding 120 ° C. is not preferred because polymerization of a monomer mainly composed of methacrylic acid ester and decomposition of the polymer tend to occur. In order to knead at the above temperature, the continuous twin-screw kneading machine usually has a temperature control section such as a jacket section, and the kneading section is specified by using an electric heater, steam, hot or cooling water, oil for temperature control, or the like. It is preferable that the temperature can be adjusted so as to reach the temperature.

After the above kneaded material is obtained, a desired resin composition can be produced by mixing the obtained slurry or clay with a curing agent after cooling or during the cooling process. At this time, the method for mixing the curing agent is not particularly limited, and for example, various kneaders and mixers can be used. Among these, it is preferable to use the continuous twin-screw kneader. For example, the one used for the above kneading can be used again, or two continuous twin-screw kneaders can be used. The mixing time may be any as long as it can be mixed uniformly, and usually about several minutes to 30 minutes, and if a continuous twin-screw kneader is used, the mixing is completed in about 1 to 5 minutes. The resin composition thus obtained is in the form of a slurry and is easy to handle, or it is in the form of clay and has no stickiness and is easy to handle such as measurement.

In the method of the present invention, fiber materials such as glass fibers, aramid fibers, carbon fibers, etc., various pattern materials, coloring Agents, coupling agents, light stabilizers,
Additives such as antioxidants, release agents, polymerization regulators, and defoamers can be used in combination.

The slurry-like resin composition produced by the method of the present invention is suitably used for casting. The clay-like resin composition can be shaped and cured by a method such as compression molding, injection molding, or extrusion molding to obtain a molded product, particularly a marble-like product. As the molding conditions, ordinary conditions are adopted. In the compression molding method, the usual molding pressure is 10 to 200 kg / cm ² and the molding temperature is 80 to 180.
℃, molding time is about 10 minutes.

[0020]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but these show only one embodiment of the present invention, and the present invention is not limited to these examples. The pressure spreadability and slurry viscosity were measured and evaluated by the following methods.

(Measurement of Pressure Extensibility)
0 g is weighed and heated by a press machine heated to a hot platen temperature of 50 ° C.
Upper heating plate / 50 μm thick nylon film / resin composition /
3T with 50μm thickness nylon film / low heat plate
Pressure is applied for 60 seconds with a load of ON, and the spread area of the resin composition is measured with an area meter [manufactured by Hayashi Denko Corporation: automatic area meter AAM-8 type].
Measure using

(Evaluation of compressive spreadability) In the above-described method, the resin composition was left to stand at room temperature for about 1 day immediately after kneading and mixing of the resin composition and in a state where the resin composition was sealed in a nylon film bag having a thickness of 50 μm. The spread area (pressure spreadability) due to pressure heating was measured, and it was evaluated whether the obtained resin composition had a change in viscosity due to standing at room temperature for 1 day (if no change was observed, it was determined that aging was not necessary). evaluated). Further, the film-shaped resin composition stretched between the nylon films was visually observed, and the presence or absence of the undissolved polymer was examined.

(Measurement of Viscosity of Slurry Resin Composition) BL
It was measured by a viscometer (manufactured by Tokyo Keiki Co., Ltd.).

(Evaluation of Viscosity of Slurry Resin Composition) According to the above method, immediately after kneading the resin composition, put the resin composition in a polyethylene container, and tightly seal the resin composition with a 50 μm-thick nylon film as a lid. The viscosity after standing at room temperature for one day was measured, and it was evaluated whether the obtained resin composition had a change in viscosity due to standing at room temperature for one day (if no change was observed, it was evaluated that aging was not necessary).

Example 1 A continuous twin-screw kneader [TEX-44, manufactured by Nippon Steel Works Co., Ltd.] heated by passing a heating medium at 80 ° C. through an attached jacket.
When the diameter 55φ, L / D = 44, rotation speed 200 rpm, power 3.7 kW] was rotated, 52 kg / hour of aluminum hydroxide having an average particle diameter of 8 μm and methacrylic resin were obtained from a raw material supply hopper on the driving motor side. Beads [a copolymer of 98% by weight of methyl methacrylate and 2% by weight of methyl acrylate, weight average molecular weight 110,000, average particle diameter 0.3 mm] are simultaneously supplied at a feed rate of 12.7 kg / hour, and 165 mm downstream from the hopper. , A mixed solution of 84 parts by weight of methyl methacrylate and 16 parts by weight of neopentyl glycol dimethacrylate is supplied at a feed rate of 8.4 kg / hour by a metering pump, and further 745 mm downstream from the hopper. 84 parts by weight of methyl methacrylate and neopentyl glycol By mixing and kneading a mixture of 16 parts by weight of dimethacrylate by a metering pump at a feed rate of 7.0 kg / hour, the dissolution of the methacrylic resin beads and the mixing of the raw material components are simultaneously performed. Were obtained continuously. After cooling the obtained clay-like material to 40 ° C., it is supplied to a continuous twin-screw extruder [PCM30 type, manufactured by Ikegai Seisakusho Co., Ltd.]
Liquid mixture 1 in which 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane is mixed with a clay-like material
By supplying 3.5 parts by weight per 00 parts by weight, a sheet-shaped resin composition was obtained. The average residence time required for dissolving and kneading the raw materials in the continuous twin-screw kneader and the mixing time of the curing agent in the continuous twin-screw extruder were both 2 minutes. The pressure spreadability immediately after mixing of the obtained resin composition was 300 cm ^2.
No residual resin beads were obtained. Also,
The pressure spreadability of the resin composition after standing at room temperature for 24 hours was 300 cm ² , and no change was observed from that immediately after mixing. 10 kg of the obtained resin composition was poured into a top plate part 600 mm ×
It is put into a vanity mold having a height of 1000 mm and a height of 50 mm and a back guard, and the mold temperature is set to an upper mold 125 ° C. and a lower mold 125 ° C., and 100 kgf / c.
Pressing and heating for 10 minutes at m ² for 600m
An acrylic artificial marble vanity of mx 1000 mm x 10 mm was obtained. Defects such as cracks were not observed on the surface of the obtained molded product, and it was very beautiful.

Example 2 A continuous twin-screw kneader heated by passing a heating medium at 80 ° C. through an attached jacket [TEX-44, manufactured by Nippon Steel Works, Ltd.
When the diameter 55φ, L / D = 44, rotation speed 200 rpm, power 3.7 kW] were rotated, 52 kg / hour of aluminum hydroxide having an average particle diameter of 8 μm was obtained from the raw material supply hopper on the drive motor side, and A methacrylic resin bead was supplied at the same feed rate of 5.6 kg / hour as in Example 1, and a mixed liquid of 84 parts by weight of methyl methacrylate and 16 parts by weight of neopentyl glycol dimethacrylate was supplied from a supply hole located 165 mm downstream of the hopper. Was supplied at a feed rate of 4.7 kg / hour by a metering pump, and a mixed solution of 84 parts by weight of methyl methacrylate and 16 parts by weight of neopentyl glycol dimethacrylate was further supplied from a supply hole located 745 mm downstream of the hopper. It is supplied at a feed rate of 17.7 kg / hour by a metering pump and kneaded. As a result, the dissolution of the methacrylic resin beads and the mixing of the raw material components were simultaneously performed, and a slurry resin composition at 70 ° C. was continuously obtained. The obtained slurry was cooled to 40 ° C., and then 16.0 k
g and 4 g of azobisisobutyronitrile were charged into a roll-type pressure kneader [D-10-20, manufactured by Moriyama Seisakusho Co., Ltd., mixing capacity 10 liters], and mixed for 10 minutes. The viscosity of the obtained slurry resin composition is 1 at 25 ° C.
The viscosity was 50 poise, and there was no change in viscosity even after 24 hours. Next, 270 g of the resin composition thus obtained was added to 25
The mixture was poured into a casting mold having a size of 0 mm × 200 mm × 3 mm, and heated at 60 ° C. for 2 hours and further at 120 ° C. for 1 hour to obtain a 250 mm × 200 mm × 3 mm plate-shaped acrylic artificial marble. The obtained molded product has no molding defects such as cracks and has an extremely beautiful surface,
It was of high commercial value.

Comparative Example 1 A continuous twin-screw kneader similar to that of Example 1 was heated by passing a heating medium at 80 ° C. through an attached jacket.
From the raw material supply hopper on the drive motor side,
μm of aluminum hydroxide was simultaneously supplied at a feed rate of 52 kg / hour and the same methacrylic resin beads 5.6 kg / hour as in Example 1, and 16 mm downstream from the hopper.
From the supply hole located at 5 mm, methyl methacrylate 84
Parts by weight and neopentyl glycol dimethacrylate 16
A part by weight of the mixture was fed by a metering pump at a feed rate of 22.4 kg / hour, mixed and kneaded, to obtain a slurry at 60 ° C. at which methacrylic resin beads remained undissolved. The obtained slurry was cooled to 40 ° C., and then 16.0 kg of the slurry and 4 g of azobisisobutyronitrile were roll-type pressure kneader [Model D-10-20, manufactured by Moriyama Seisakusho Co., Ltd.] , Mixing capacity of 10 liters]. The viscosity of the obtained slurry resin composition was 70 poise at 25 ° C.
After the lapse of time, the viscosity increased to 140 poise, and a resin composition having high property stability was not obtained.

[0028]

As described above, according to the method of the present invention, a slurry-like molding material suitable for the casting molding method or a clay-like molding material suitable for the press molding method can be obtained, and the method for artificial marble and the like can be obtained. It is suitable as a method for easily and inexpensively producing the molding material of (1).

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08L 33/06 C08L 33/06 // (C04B 26/06 14:36 16:04) 111: 54 (72) Inventor Kazuhiko Ma 2-28 Kurashiki-cho, Nakajo-cho, Kitakanbara-gun, Niigata Prefecture Kuraray Co., Ltd.

Claims (1)

[Claims] 1. A monomer mainly composed of methacrylate, a methacrylate polymer and an inorganic filler are charged into a continuous twin-screw kneader and kneaded at a temperature of 65 to 120 ° C. to form a slurry. A method for producing a resin composition by mixing a curing agent after cooling or during the cooling process to the obtained slurry or clay, and then producing a resin composition mainly comprising a methacrylic acid ester. A method for producing a resin composition, comprising dividing the charged monomers into a continuous twin-screw kneader and charging them.