JPS61120804A - Production of luminescent artificial stone molding - Google Patents

Abstract

PURPOSE:To obtain artificial marble having a feeling of luminescence with deepness and solidness, by pouring a mixture obtained by adding a light-storing pigment to a composition comprising a radical-polymerizable resin syrup and a specified filler, etc., into a mold and curing the mixture. CONSTITUTION:A casting composition is obtained by mixing 20-60wt% radical- polymerizable resin syrup (a) with 40-80wt% inorganic filler (b) having a high whiteness (Hunter's whiteness >=about 85%) and a refractive index (about 1.47-1.59) approximate to that of said resin, 0.5-8wt% light-storing dye (c) and a radical initiator (d) (e.g., benzoyl peroxide). After thorough mixing by agitation, this composition is poured into a mold and polymerized and cured by heating. A suitable example of the resin syrup (a) is one obtained by partially (conversion of about 10-30%) polymerizing a monomer based on methyl methacrylate. Suitable examples of the fillers (b) include fine powders of talc, silica and alumina trihydrate, and suitable examples of the light-storing pigments (c) include betaZnS:Cu type and CuS:Bi type.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a luminescent artificial stone molded product, and more specifically, it has a transparent feeling and a deep three-dimensional luminescent feeling, The present invention relates to a method for producing luminescent artificial stone useful for displays, signboards, ornaments, display shelves, etc. in boutiques, jewelry stores, gift floors and other merchandise stores, public facilities and entertainment facilities.

Prior Art and Technical Problems of the Invention In general, the easiest way to impart luminescence to articles is to use fluorescent pigments. It is used in a wide range of applications, including for signs, and by mixing it with plastic molding materials to make it emissive. However, most of these applications are used only from a practical standpoint, such as to notify the presence of substances at night, to display characters, or are used for some toys.
Currently, there are only a limited number of articles that have luminescent properties and can be used for decorative purposes. This is because when the method of use is painting, the light is emitted only from a flat surface, and the surface condition does not have the appearance of a decorative object.For molded products mixed with shattered plastic molding materials, the plastic feel is This is because it is for decoration and has no value compared to 1. However, this is because the night indicator function cannot be activated.

Outline and Purpose of the Invention The present inventors incorporated a luminescent pigment into a composition consisting of a radically polymerizable resin syrup and a specific filler, and when injecting this into a mold and curing it, the inventors achieved depth and three-dimensionality. It has been discovered that a unique artificial marble molded product having a certain luminescent feel can be obtained. That is, an object of the present invention is to provide an artificial marble having a luminescent feeling with depth and three-dimensionality.

Another object of the present invention is to have a high-quality feel, that is, texture or appearance characteristics that can be used as a decorative material, and also to have a high degree of workability that allows it to be processed into the shape and size of clay. The present invention provides a method for producing luminescent artificial stone.

Structure of the Invention According to the present invention, 20 to 60% by weight of a radical polymerizable resin syrup, 4 to 8% by weight of an inorganic filler whose whiteness is high and whose refractive index is close to that of the resin, and 0.0 to 8% by weight of a phosphorescent pigment.
A method for manufacturing a luminescent artificial stone molded article is provided, which comprises injecting a composition containing a radical initiator in an amount of 5 to 8 weight percent and a catalytic amount into a mold, and polymerizing and curing the composition.

Features and Effects of the Invention The present invention is a radical polymerizable resin syrup and a white inorganic filler having a refractive index close to the refractive index of the contact material with a phosphorescent pigment (-1). It has the following characteristics.

In general, it is defined as a substance that emits color without heat when the phosphor melts and electrons are brought to an excited state by applying light or other stimuli and then transition to a lower energy level state. The lifetime of this excited state electron is 10-4 to 101
Although it is said to be on the order of seconds, in reality, afterglow phenomenon appears even when the stimulus is removed, and the degree of attenuation varies from 10-1 seconds to several thousand yen depending on the type of phosphor. Extends.

In the luminescent pigment used in the present invention, electrons or holes are captured in crystal traps, the energy of the absorbed light is accumulated in the pigment (phosphorescence), and it is thermally released and emits light upon recombination. It is characterized by an extremely long afterglow.

According to the present invention, by dispersing the phosphorescent pigment in a radical polymerizable resin syrup, the phosphorescent pigment is dispersed in the resin matrix in a finer manner than when the pigment is dispersed in an ordinary melt molding resin. It becomes possible to uniformly disperse it in the form of particles. Furthermore, by dispersing the phosphorescent pigment in the syrup together with a relatively large amount of inorganic filler, the filler becomes a carrier for dispersing the phosphorescent pigment, and a more uniform and uniform dispersion form can be obtained.

Furthermore, the radical polymerization hardened resin used in the present invention, especially the acrylic resin, is! It has the advantage of being particularly excellent in transparency and refractive index among various resins, and furthermore, the filler dispersed in the resin has a refractive index close to that of the resin. In the present invention, luminescent pigments with extremely long afterglow properties are uniformly dispersed in these systems. A sense of luminescence with depth can be obtained, and together with the fact that the molded product exhibits marble-like appearance characteristics, a high-quality decorative effect can be obtained.

Furthermore, in the artificial stone of the present invention, the resin itself has excellent workability, and the above-mentioned amount of inorganic filler is blended into the resin matrix, so that it can be used as a woodworking tool or a hardening knife. It also has the advantage that it can be freely cut, cut out, etc. with the cutting tool it has, and is excellent in various processability.

Preferred Embodiments of the Invention The preferred embodiments of the present invention will be described in detail below.

Resin component In this specification, a radical polymerization type or hardening type resin syrup means that this substance is cured into a solid resin form by a radical initiator, that is, it is solidified. Nor does it require three-dimensional crosslinking.

Radical polymerization type resin syrup refers to a syrup-like liquid composition containing a resin prepolymer and a monomer. The resin prepolymer component and 17 include various acrylic prepolymers, unsaturated polyester prepolymers, acrylic urethane prepolymers, vinyl urethane prepolymers, bismaleimide prepolymers, etc., and the monomer components include radical polymerization Ethylenically unsaturated monomers having properties such as acrylic monomers, styrene monomers, vinyl ester monomers, halogenated vinyl monomers, and vinyl ether monomers.
Examples include combinations of more than one species. Of course, the resin prepolymer component and monomer component described above form a homogeneous syrup.
Suitable resin syrups are acrylic resin syrups and unsaturated polyester syrups, and especially methyl resin syrups, which are particularly excellent in terms of luminescence, appearance characteristics, and weather resistance. It is an acrylic resin syrup mainly composed of methacrylate.

This methacrylic resin syrup is obtained by adding a small amount of a radical polymerization initiator to a monomer mainly composed of methyl methacrylate, and partially polymerizing the mixture by heating in a prepolymerization pot. The degree of partial polymerization is a polymerization rate of 10 to 30%.
An appropriate range is as follows. For the purpose of syrup moldability and resin modification (-), styrenic monomers such as styrene and vinyltoluene, and other acrylic monomers such as ethyl acrylate and butyl methacrylate are used before or after partial polymerization. Monomers can be mixed.These modifying monomers are preferably used in the range of 10 to 6% by weight per syrup.

The raw material resin syrup has a molecular weight of 500 to 2000 in terms of mixability with the components described later, castability, and post-polymerization curability.
It is desirable to have a viscosity of centiboise (CPS).

Filler In the present invention, an inorganic filler having a high degree of whiteness and a refractive index close to that of the resin described above is used. There are so many types of inorganic fillers known that there is no time to enumerate them.
Among these, one that satisfies the above-mentioned conditions may be selected depending on the type of resin used.

Examples of fillers suitable for the purpose of the present invention include finely powdered talc, silica, alumina filtrate, and magnesium hydroxide. These fillers can be used alone or in combination of two or more, and can also be used in combination with fillers other than those exemplified.

In the present invention, as already pointed out (~), using a material with high whiteness and a refractive index close to that of resin improves the transparency of the artificial stone and increases the brightness and luminescence amount of the phosphorescent pigment mixed with it. This is an important point in giving a three-dimensional luminous effect.

The Hunter whiteness of the filler used is 85% or more, especially 90%.
It is desirable for the refractive index to be within the range of 1.47 to 1.59. Further, the particle size is preferably within the range of about 150 to 300 mesh according to the Tyler standard.

Among the fillers, talc has a Mohs hardness of 1 to 1.
It is a particularly suitable filler for the purpose of the present invention because it is very soft with a rating of 2 and provides molded products with excellent workability such as machinability, cuttability, and saw-inkability.

Luminous Pigment The phosphorescent pigment used in the present invention is a fluorescent pigment with an extremely long afterglow property, and such a recombination type afterglow is unique to crystalline phosphors. This luminescent pigment is made by adding a trace amount of impurity called an activator to sulfides such as zinc sulfide and calcium sulfide, and is suitable for the purpose of the present invention.
Examples include ab:Bi (light emission: purple) and βZnS:Cu (light emission: yellow-green).

Casting composition According to the present invention, radical polymerization type syrup 20 to 60
% by weight, 40-80% by weight of the filler, 0.0% by weight of the luminescent pigment.
A casting composition is prepared by intimately mixing 5 to 8 parts by weight and a catalytic amount of a radical initiator.

=10- It is also important for the purpose of the present invention to blend these components in the above ratio. For example, if the amount of filler used is less than the above range, the above-mentioned effects associated with the filler blend cannot be expected. On the other hand, if the amount exceeds the above range, the mechanical strength of the molded product will decrease and the durability will also decrease. Furthermore, if the amount of luminescent pigment blended is less than the above range, the desired luminescent effect cannot be obtained, and if it is used in an amount greater than the above range, it is economically disadvantageous, and the desired luxurious feel and deep taste cannot be achieved. A certain luminous window will be lost.

As a radical initiator, benzoyl peroxide,
Organic peroxides such as lauryl peroxide and azo compounds such as azobisisobutyronitrile are used; these initiators are used in a so-called catalytic amount, generally 0 per resin syrup.
．． It is used in amounts of 0.05 to 2% by weight, in particular 1.2 to 2% by weight.

The casting composition of the present invention may contain known auxiliary agents or compounding agents, such as coloring agents, viscosity modifiers, antioxidants, mold release agents, etc., to the extent that their essence is not impaired. It can be formulated in a prescription.

Molding and Curing After the above-described composition is sufficiently mixed and stirred, it is defoamed if necessary, poured into a mold having an arbitrary shape, and the composition is solidified by heating and polymerization. In addition to the cell casting method, a continuous casting method in which casting is performed continuously can also be used for casting.

Further, the polymerization can be carried out by any method known per se, for example, a one-stage polymerization method or a two-stage polymerization method (
Eight. For example, the latter two-stage polymerization method employs a method consisting of a combination of polymerization at a relatively low temperature in the first stage and polymerization at a higher temperature in the second stage.

Further, for the purpose of removing internal strain caused by polymerization shrinkage, heat treatment can be performed at a temperature equal to or higher than the glass transition temperature CTf of the resin.

Applications The artificial stone molded product of the present invention emits light with depth and three-dimensionality at night, and has outstanding decorative properties even during the day, and can be subjected to advanced post-processing. It has the advantage of For example, it is easy to cut out a name for displaying a store name, etc. from a thick plate-shaped molded product, and the former can be easily used for various purposes.

EXAMPLES The present invention will be explained with the following examples.0 Example 1 0.1% by weight of benzoyl peroxide was added to methyl methacrylate and heated to a temperature of 8DC in a prepolymerization kettle to give a polymerization rate of about 25%. Acrylic resin syrup (viscosity 1
00 D cps) was produced.

This resin syrup 35% by weight, whiteness 95,
62% by weight of fine talc powder with a refractive index of 1.57 and an average particle size of 12 microns, 6% by weight of ZnS:Cu-based phosphorescent pigment, and 05% by weight of benzoyl peroxide per resin syrup were homogeneously mixed and stirred, followed by defoaming. Preparation of casting composition 1
~is.

This composition has an internal dimension of 2000m+nX1000m
+n×15Illll mold, 80tTX1
It was polymerized and cured under the conditions of hours.

As described above, the molded product obtained in [7] had a marble-like appearance, and exhibited not only a surface but also a deep and three-dimensional luminous window, and its luminous intensity was also sufficient.

It is highly workable and can be cut with a wood saw.
Cutting with a plane and cutting with a router were also easy.

Examples 2-F An artificial stone molded article was produced in the same manner as in Example 1 except that silica, alumina filtrate, and magnesium hydroxide were used in place of talc.

These molded products were only slightly inferior in processability to those of Example 1, and the appearance characteristics and light emitting windows were similar to those of Example 1.

Claims (4)

[Claims] (1) Radical polymerization type resin syrup 20 to 60% by weight
A composition containing 40 to 80% by weight of an inorganic filler with high whiteness and a refractive index close to that of the resin, 0.5 to 8% by weight of a luminescent pigment, and a catalytic amount of a radical initiator is injected into a mold. A method for producing a luminescent artificial stone molded product, which comprises polymerizing and curing the product. (2) The method according to claim 1, wherein the radically polymerizable resin is an acrylic resin or an unsaturated polyester resin. (3) The method according to claim 1, wherein the inorganic filler is a finely powdered product of talc, silica, or alumina trihydrate. (4) The method according to claim 1, wherein the luminescent pigment is a βZnS:Cu type or CuS:Bi type luminescent pigment.