JP5645258B2 - Manufacturing method of artificial marble - Google Patents

Description

  The present invention relates to a method for producing artificial marble.

  Conventionally, artificial marble having the same material feeling, texture, and natural feeling as natural marble has been used in a wide range of building materials such as houses, kitchens, baths, vanities, and the like.

  In the production of such artificial marble, patterning is performed, and the formed pattern gives an impression that is almost as close as natural stone.

  Regarding the patterning of the artificial marble, conventionally, a method has been used in which a ground product of a cured or semi-cured resin is mixed with the artificial marble as a pattern material (see Patent Documents 1 and 2). Thereby, a pattern like a natural stone can be expressed.

  However, a method of mixing a ground product of a cured or semi-cured resin into an artificial marble can express a crushed natural stone pattern, but cannot produce a texture like a natural stone with a flowing pattern.

  A technique for imparting a pattern closer to the flow to the artificial marble than the crushed using a resin component for the pattern material having fluidity is also being studied. In Patent Document 3, as a technique for imparting a flow pattern, a base color acrylic resin mixture and a flowable acrylic resin are mixed and added, and both these mixtures are injected into a mold and cured by heating. A method has been proposed. In Patent Document 4, a semi-cured gel-like polymer having fluidity obtained by curing in the presence of a curing agent is used as a patterning material, mixed with a curable composition for dough, and molded and cured. A method for obtaining artificial marble with streaks and cloud-like patterns has been proposed.

JP-A-10-156840 JP 2003-191254 A JP 61-63418 A JP-A-2-157146

  However, even in the prior arts such as Patent Documents 3 and 4, the pattern pattern tends to have a texture having a characteristic according to the manufacturing method, and it is generally difficult to produce a texture like a natural stone having a flowing pattern. Therefore, a new method for imparting a flow pattern has been desired.

  This invention is made | formed in view of the situation as mentioned above, and makes it the subject to provide the manufacturing method of the artificial marble which can take out the texture like the natural stone which has a flow pattern.

  In order to solve the above problems, the method for producing an artificial marble of the present invention is obtained by dissolving a methyl methacrylate polymer in a methyl methacrylate monomer in the method for producing an artificial marble having a flowing pattern. After forming methyl methacrylate syrup into a rod shape, the step of volatilizing the methyl methacrylate monomer to produce a rod-shaped handle material, the methyl methacrylate polymer, the methyl methacrylate monomer, and the crosslinking A step of preparing a resin mixture by mixing an acrylic resin composition containing an agent and having a specific gravity different from that of the pattern material and the pattern material, a step of casting the resin mixture into a mold, and the resin mixture And a step of curing and molding the cast mold in a state where a surface of the cavity forming the flow pattern is inclined or parallel to the vertical direction.

  In this method for producing artificial marble, the acrylic resin composition preferably contains a filler.

  In this method for producing artificial marble, the pattern material is preferably a cut product having a thickness of 0.2 to 2 mm and a width of 1 to 3 mm.

  According to the method for producing artificial marble of the present invention, a texture like a natural stone having a flowing pattern can be produced.

It is a figure explaining an example of the process of hardening-molding in the state where the surface which forms the flow pattern in the cavity of the metal mold | die which injected the resin mixture inclined, (a) is a side view of a cavity, (b) is a figure of a cavity. It is a perspective view. It is the photograph of the surface in which the flow pattern of the artificial marble obtained in the Example was formed.

  The present invention is described in detail below.

  In the method for producing artificial marble of the present invention, as the first step, methyl methacrylate syrup obtained by dissolving a methyl methacrylate polymer in a methyl methacrylate monomer is shaped into a rod, and then methyl methacrylate is obtained. Volatile monomers are volatilized to produce a rod-shaped handle material.

  The methyl methacrylate polymer is a polymer having a methyl methacrylate unit as a main component, and may be a copolymer with another copolymerizable monomer in addition to a homopolymer of methyl methacrylate. Good.

  Other monomers that can be copolymerized are not particularly limited. For example, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate , Isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, lauryl (meth) acrylate , (Meth) acrylic esters such as cyclohexyl (meth) acrylate, unsaturated acids such as methacrylic acid and acrylic acid, styrene such as styrene, vinyltoluene, α-methylstyrene, t-butylstyrene, chlorostyrene and derivatives thereof , Vinyl acetate, vinyl propionate and other vinyl esters, acrylonitrile, Or the like can be used acrylonitrile. These may be used alone or in combination of two or more.

  The methyl methacrylate polymer can be produced by a known radical polymerization method such as bulk polymerization, solution polymerization, suspension polymerization and the like.

  The weight average molecular weight of the methyl methacrylate polymer is not particularly limited. For example, it is 50,000 to 150,000 as a value measured using a methyl methacrylate polymer as a standard sample using GPC (gel permeation chromatography). Those within the range can be used.

  The methyl methacrylate polymer has a methyl methacrylate ratio of 50 to 100% by mass, preferably 90 to 100% by mass, of all monomer units. If this ratio is too small, it may be difficult to dissolve in the methyl methacrylate monomer.

  The methyl methacrylate monomer is a monomer having methyl methacrylate as a main component, and may be a monomer mixture with other monomers capable of copolymerization in addition to methyl methacrylate alone. Good.

  Although it does not specifically limit as another monomer which can be copolymerized, For example, what was illustrated in the above can be used. These may be used alone or in combination of two or more.

  The methyl methacrylate monomer has a methyl methacrylate ratio of 50 to 100% by mass, preferably 90 to 100% by mass, based on all monomers. If this ratio is too small, the methyl methacrylate polymer may be difficult to dissolve.

  Methyl methacrylate syrup can be obtained by dissolving a methyl methacrylate polymer in a methyl methacrylate monomer. The ratio of the methyl methacrylate polymer to the methyl methacrylate monomer is not particularly limited, and can be appropriately determined in consideration of the viscosity, volatilization rate and the like suitable for shaping.

  In addition to the methyl methacrylate polymer and the methyl methacrylate monomer, the methyl methacrylate syrup may contain a colorant such as a toner, and may contain other components as necessary. .

  The method of forming this methyl methacrylate syrup into a rod shape is not particularly limited. For example, a method of extruding methyl methacrylate syrup from a hole for shaping, a method of forming a sheet shape and then cutting into a rod shape, casting And the method of rolling methyl syrup methacrylate on a flat plate can be used.

  Among these methods, in the method of extruding methyl methacrylate syrup from the shaping hole, the methyl methacrylate syrup is continuously passed through the hole having a shape corresponding to the cross-sectional shape of the rod-shaped handle material and extruded. Thereby, after shaping a long pattern material, a pattern material can be obtained as a cut product cut into an appropriate length.

  In this case, the pattern material is preferably a cut product having a thickness of 0.2 to 2 mm and a width of 1 to 3 mm. The same applies to the method of cutting into a rod shape after shaping into the sheet shape. By using such a pattern material, a flow pattern close to natural stone can be imparted to the artificial marble.

  After shaping methyl methacrylate syrup into a rod shape, the methyl methacrylate monomer is volatilized to produce a rod-shaped handle material. The rod-shaped handle material obtained in this way is not limited to a straight one but may be a curved one. For example, the method of extruding from the hole may be bent at the time of extrusion, and the method of casting may be bent or change shape when poured into a mold.

  In the method for producing artificial marble of the present invention, as the next step, an acrylic resin composition containing a methyl methacrylate polymer, a methyl methacrylate monomer, and a crosslinking agent and having a specific gravity different from that of the pattern material, A resin mixture is prepared by mixing the material.

  Because the specific gravity is different in this way, the pattern material is caused by the difference in specific gravity when the molding is performed in a state where the flow pattern forming surface in the cavity of the casting mold is inclined or parallel to the vertical direction. It floats or sinks on the surface of the cavity where the flow pattern is formed. A flow pattern can be formed by curing and molding in this state.

  The methyl methacrylate polymer of the acrylic resin composition is not particularly limited, but the same ones as described above can be used. Moreover, you may contain the prepolymer.

  Although it does not specifically limit as a methyl methacrylate type monomer of an acrylic resin composition, The thing similar to the above-mentioned thing can be used.

  The methyl methacrylate polymer and methyl methacrylate monomer used for methyl methacrylate syrup are the same as or different from the methyl methacrylate polymer and methyl methacrylate monomer used for the acrylic resin composition. Also good.

  The blending ratio of the methyl methacrylate polymer and the methyl methacrylate monomer in the acrylic resin composition is preferably 10:90 to 50:50 by mass ratio. If the ratio of the methyl methacrylate monomer is too large, the cured product may crack. If the ratio of the methyl methacrylate monomer is too small, the viscosity of the acrylic resin composition becomes high, and workability may be deteriorated.

  Although it does not specifically limit as a crosslinking agent of an acrylic resin composition, For example, di (meth) acrylic acid ethylene glycol, di (meth) acrylic acid-1,3-propyleneglycodi (meth) acrylic acid neopentyl glycol, etc. Alkylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, divinylbenzene di (meth) acrylate, allyl di (meth) acrylate, diallyl phthalate, di ( (Meth) vinyl acrylate, vinyl crotonate and the like can be used. These may be used alone or in combination of two or more.

  As for the compounding quantity of a crosslinking agent, 1-20 mass% is preferable with respect to the total amount of a methyl methacrylate polymer and a methyl methacrylate monomer. When there are too few compounding quantities of a crosslinking agent, the heat resistance of the artificial marble obtained may fall. When there is too much content of a crosslinking agent, the artificial marble obtained may become weak.

  A filler can be mix | blended with an acrylic resin composition. By mix | blending a filler, the specific gravity of an acrylic resin composition can be adjusted and the specific gravity difference with a pattern material can be provided.

  Although it does not specifically limit as a filler, For example, silica sand, ceramic sand, silica, glass powder, calcium carbonate, mica, aluminum hydroxide, aluminum oxide, barium sulfate, clay, talc, etc. can be used. These may be used alone or in combination of two or more. As the filler, for example, one having an average particle diameter of 0.1 to 100 μm can be used.

  The blending amount of the filler is preferably 20 to 400 parts by mass with respect to 100 parts by mass of the total amount of the methyl methacrylate polymer and the methyl methacrylate monomer. When there are too few compounding quantities of a filler, it may become difficult to provide sufficient specific gravity difference with an acrylic resin composition. If the amount of the filler is too large, the physical properties and appearance of the artificial marble may be deteriorated.

  By blending a filler with a large specific gravity, the specific gravity of the pattern material is kept relatively light, and the surface forming the flow pattern in the cavity of the casting mold is inclined or parallel to the vertical direction. Curing is performed in the state. Thereby, it can harden | cure in the state which floated the swollen pattern material in the cavity, and a flow pattern can be formed.

  A hardening agent (polymerization initiator) can be mix | blended with an acrylic resin composition. The curing agent is not particularly limited, and for example, a known curing agent for polymerization of a monomer mainly composed of methyl methacrylate can be used. Specifically, for example, t-butylperoxy-2-ethyl acetate, t-butylperoxy-2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, t-hexylperoxy- Organic peroxides such as 2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,2′azobisisobutyronitrile, 2,2′azobis Known redox initiators mainly composed of azo compounds such as (2,4-dimethylvaleronitrile), organic peroxides and reducing compounds such as amines and mercaptans, benzoin, benzoin ethers, 1- Hydrohexyl phenyl ketone, benzyl dimethyl ketal, acyl phosphenoxide, benzophenone, Michler ketone, thioxanthone, etc. It can be used a photopolymerization initiator and the like in combination with a photosensitizer agent, if necessary.

  The blending amount of the curing agent is 0.1 to 5% by mass with respect to the total amount of the methyl methacrylate polymer and the methyl methacrylate monomer in consideration of the curing characteristics and the physical properties of the resulting artificial marble. preferable.

  In the acrylic resin composition, other components than the above-mentioned components can be blended within a range not impairing the effects of the present invention. Examples of such other components include a colorant such as toner, an ultraviolet absorber, a viscosity reducer, an internal release agent, and a reinforcing agent.

  The acrylic resin composition is mixed with a pattern material to prepare a resin mixture. The acrylic resin composition can be prepared by blending the above-mentioned components at a predetermined ratio, and mixing and stirring with a stirrer or the like. Moreover, the rod-shaped pattern material produced beforehand at the time of preparation of an acrylic resin composition or after preparation is mixed and it is set as a resin mixture. The prepared resin mixture is subjected to vacuum defoaming treatment under a reduced pressure of about 20 to 50 Torr, for example.

  In the method for producing artificial marble of the present invention, the resin mixture is poured into a mold as the next step. Specifically, the vacuum degassed resin mixture is released from the reduced pressure state and poured into a mold having a predetermined shape. The mold has a cavity corresponding to the shape of the target artificial marble. For example, a flat plate having a cavity inside a pair of opposed plate members can be used.

  For example, as a casting method using a mold, a method of casting and polymerizing into a mold having a desired shape made of metal, resin, etc., composed of two glass plates or metal plates, a soft sealing material, and a clamp For example, a continuous cell using two continuous belts made of stainless steel can be used.

  In the method for producing artificial marble according to the present invention, as a last step, a mold in which a resin mixture is cast is cured and molded in a state where the flow pattern in the cavity is inclined or parallel to the vertical direction. To do.

  Referring to FIGS. 1A and 1B as an example, as shown in the side view of FIG. 1A, a resin mixture 2 containing a rod-shaped handle material 2a is poured and filled into a cavity 1 of a mold. . Then, the molding is performed in a state where the surface 1a forming the flow pattern in the cavity 1 is inclined or parallel to the vertical direction at an angle θ. As a result, as shown in the perspective view of FIG. 1 (b), the pattern material 2a in the resin mixture 2 is raised in the direction of the surface 1a on which the flow pattern is formed due to the difference in specific gravity. A flow pattern by the pattern material 2a is formed on the surface 1a forming the flow pattern.

  At this time, the pattern material 2 a made of the methyl methacrylate polymer is swollen in the resin mixture 2. By molding and curing in this swollen state, an artificial marble having a flow pattern close to natural stone can be produced.

  The angle [theta] between the surface forming the flow pattern in the cavity and the vertical direction is preferably 0 to 40 [deg.] In consideration of the workability at the time of molding and the characteristics of the artificial marble after curing.

  Curing molding can be performed by heating the mold at a temperature of 50 to 110 ° C. for 30 to 150 minutes, for example.

  Although it does not specifically limit as a heating method at the time of hardening shaping | molding, A well-known method, for example, the method of heating with heat sources, such as warm air, warm water, an infrared heater, etc. can be used.

  In the above, as a method for adjusting the specific gravity, the method of increasing the specific gravity of the acrylic resin composition with the filler has been mainly described. However, in the present invention, by increasing the specific gravity of the pattern material, the case of FIG. Conversely, the pattern material can be allowed to settle. For example, a method in which an acrylic resin composition is blended with a component having a small specific gravity to relatively reduce the specific gravity of the acrylic resin composition, a component having a large specific gravity is blended in methyl methacrylate syrup, and the specific gravity of the pattern material is relatively A method of increasing the size can be used. In addition, the method of increasing the specific gravity of the acrylic resin composition with a filler is preferable because a flow pattern close to natural stone can be stably formed.

  The artificial marble produced by the present invention can be suitably used for building materials such as houses, kitchens, baths, vanity tables, and the like.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

The following were used as raw materials for methyl syrup methacrylate and the acrylic resin composition.
1. Methyl methacrylate syrup (methyl methacrylate polymer)
Polymethyl methacrylate (“Methyl methacrylate polymer” manufactured by Wako Pure Chemical Industries, Ltd.)
(Methyl methacrylate monomer)
Methyl methacrylate (“Methyl methacrylate” manufactured by Wako Pure Chemical Industries, Ltd.)
(Coloring agent)
Black toner for acrylic resin ("Color for acrylic resin" manufactured by Dainichi Seikagaku Co., Ltd.)

2. Acrylic resin composition (methyl methacrylate polymer)
Polymethyl methacrylate (“Methyl methacrylate polymer” manufactured by Wako Pure Chemical Industries, Ltd.)
(Methyl methacrylate monomer)
Methyl methacrylate (“Methyl methacrylate” manufactured by Wako Pure Chemical Industries, Ltd.)
(Coloring agent)
White toner for acrylic resin ("Color for acrylic resin" manufactured by Dainichi Seika Kogyo Co., Ltd.)
(Crosslinking agent)
Ethylene glycol dimethacrylate (“Ethylene dimethacrylate” manufactured by Wako Pure Chemical Industries, Ltd.)
(Curing agent)
Benzoyl peroxide ("Parkadox" manufactured by Kayaku Akzo Co., Ltd.)
(filler)
Silica sand ("Ube quartz sand" manufactured by Ube Sand Co., Ltd.)

(1) Preparation of methyl methacrylate syrup and handle material First, 75 parts by mass of polymethyl methacrylate was dissolved in 25 parts by mass of methyl methacrylate (mass ratio 75/25) to prepare methyl syrup methacrylate.
5 parts by mass of methyl syrup methacrylate and 0.2 part by mass of toner were mixed and formed into a sheet shape, and then cut into a rod shape with scissors. Thereafter, methyl methacrylate was volatilized, solidified into a solid state, and then cut to prepare a rod-shaped handle material having a thickness of 1 mm, a width of 1 mm, and a length of 25 mm.

(2) Preparation of acrylic resin composition and resin mixture First, 75 parts by mass of polymethyl methacrylate was dissolved in 25 parts by mass of methyl methacrylate (mass ratio 75/25) to prepare methyl syrup methacrylate.

  Acrylic resin prepared by mixing 50 parts by weight of methyl syrup methacrylate, 0.2 parts by weight of crosslinking agent, 0.5 parts by weight of toner, 0.2 parts by weight of curing agent, 50 parts by weight of transparent silica sand, and 5 parts by weight of ceramic sand. A composition was prepared. A pattern material was added thereto, and further mixed and defoamed to obtain a resin mixture.

(3) Curing Molding The obtained resin mixture is poured into a plate-shaped casting mold having a cavity having a thickness of 8 mm and a width and width of 100 mm × 100 mm, and the surface forming the flow pattern in the mold cavity is vertical. In an inclined state by 10 °, the resultant was placed in a dryer at a temperature of 90 ° C. for 1 hour for curing and molding to obtain an artificial marble.

  A photograph of the resulting artificial marble is shown in FIG. The artificial marble surface on the surface side (upward surface side) forming the flow pattern in the cavity of the mold had a natural stone-like flow pattern.

1 Cavity 1a Surface Forming Flow Pattern 2 Resin Mixture 2a Pattern Material

Claims (3)

In a method for producing an artificial marble having a flowing pattern, methyl methacrylate syrup obtained by dissolving a methyl methacrylate polymer in a methyl methacrylate monomer is shaped into a rod, and then the methyl methacrylate monomer A process for producing a rod-shaped handle material by volatilizing the resin, and an acrylic resin composition and a handle material that contain a methyl methacrylate polymer, a methyl methacrylate monomer, and a crosslinking agent and have a specific gravity different from that of the handle material forming a step, a step of casting the resin mixture into a mold cavity, said mold said resin mixture was cast, the flow pattern in the mold cavity to prepare a mixed to the resin mixture bets by surface to be is heated in a state where an inclined or parallel to the vertical direction, Engineering for curing and molding the handle member by embossing or sedimentation from the resin mixture Artificial marble method for producing characterized in that it comprises and.   The method for producing artificial marble according to claim 1, wherein the acrylic resin composition contains a filler. The method for producing an artificial marble according to claim 1 or 2, wherein the pattern material is a cut product having a thickness of 0.2 to 2 mm and a width of 1 to 3 mm and cut to an appropriate length .