JP3921754B2 - Acrylic plate for driving hard material and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an acrylic plate that is less prone to crack when a hard material is driven.
[0002]
[Prior art]
Methyl methacrylate resin based on methyl methacrylate is excellent in transparency, surface gloss, weather resistance, mechanical properties, etc., so it can be used in various applications such as lighting equipment, automotive parts, signboards, and building materials. Widely used.
Especially in the interior of stores and houses, it is also used for furniture and partitions.
[0003]
As a characteristic of a general methyl methacrylate resin, there is a problem that impact strength is low.
That is, when trying to drive in a nail, a screw, etc., there is often a problem that cracks tend to occur and the appearance is impaired.
[0004]
[Problems to be solved by the invention]
In view of such circumstances, the present inventor has intensively studied an acrylic plate that does not easily crack even when nails or screws are driven in. As a result, an acrylic resin comprising a methyl methacrylate polymer and a resin composition containing a specific amount of plasticizer. The present inventors have found that cracks are unlikely to occur even when nails or screws are driven into the plate, leading to the present invention.
[0005]
[Means for Solving the Problems]
That is, the present invention is an acrylic plate for driving a hard material comprising a resin composition containing 50 to 85% by weight of a methyl methacrylate polymer and 15 to 50% by weight of a plasticizer compatible therewith.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The methyl methacrylate polymer in the present invention refers to a polymer of a mixture of unsaturated monomers mainly composed of methyl methacrylate.
The mixture of unsaturated monomers mainly composed of methyl methacrylate here is a mixture of 50% by weight or more of methyl methacrylate and an unsaturated monomer copolymerizable with methyl methacrylate.
[0007]
Examples of unsaturated monomers copolymerizable with methyl methacrylate include methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) ) Esters of methacrylic acid or acrylic acid such as acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate and aliphatic, aromatic and alicyclic alcohols; (Meth) acrylic monomers of hydroxyalkyl esters such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate; acrylic acid, methacrylic acid Unsaturated acids; styrene, styrene monomers such as α- methylstyrene acrylonitrile, methacrylonitrile, maleic anhydride, phenyl maleimide, cyclohexyl maleimide, monofunctional vinyl acetate unsaturated monomers and,
[0008]
Allyl methacrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, divinylbenzene, diallyl phthalate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, Tetramethylol methane Tetra (meth) acrylate, urethane acrylate, epoxy acrylate, etc. have few double bonds capable of radical polymerization in one molecule. Both unsaturated monomer of the polyfunctional and the like having two.
These unsaturated monomers are used alone or in combination of two or more.
[0009]
For the methyl methacrylate polymer, if necessary, known additives, such as antioxidants, ultraviolet absorbers, polymerization inhibitors, chain transfer agents, mold release agents, flame retardants, dyes, pigments, Inorganic fillers, reinforcing agents and the like can also be added.
[0010]
Examples of the plasticizer compatible with the methyl methacrylate polymer in the present invention include aromatic esters such as phthalic acid esters and benzoic acid esters; sebacic acid esters, adipic acid esters, azelaic acid esters, maleic acid esters, fumaric acid. Aliphatic ester types such as esters and citric acid esters; in addition, phosphoric acid ester types; polyesters and other plasticizers.
Of these, aliphatic ester plasticizers are preferred because of their excellent light resistance.
These plasticizers may be used alone or in combination of two or more.
[0011]
In particular, acetyltributyl citrate is preferable from the physical properties of the acrylic plate for driving hard materials.
[0012]
The addition amount of the compatible plasticizer is preferably 15 to 50% by weight of the acrylic plate for driving a hard material. If the addition amount is less than 15% by weight, the effect of preventing the occurrence of sufficient cracks cannot be obtained. Conversely, if the addition amount exceeds 50% by weight, the plasticizer oozes out on the surface of the acrylic plate, resulting in poor handling. In addition, it is not preferable because sufficient rigidity for use as a building material cannot be obtained.
[0013]
Examples of the method for producing an acrylic plate for driving a hard material in the present invention include, for example, a method of obtaining an acrylic plate using an apparatus such as an extruder or a roll of a methyl methacrylate polymer and a plasticizer, and a methyl methacrylate polymer. When manufacturing by suspension polymerization or emulsion polymerization, a plasticizer is allowed to coexist to obtain polymer particles containing the plasticizer, and further processed into a plate shape by an extruder or a press, mainly composed of methyl methacrylate. And a method of mixing a mixture of unsaturated monomers with a plasticizer and polymerizing the mixture into a plate shape.
[0014]
In particular, from the viewpoint of suppressing the heat coloring of the plasticizer, a method of mixing a mixture of an unsaturated monomer mainly composed of methyl methacrylate and a plasticizer and further polymerizing it into a plate shape is preferable.
Hereinafter, this method will be described.
First, a syrup is prepared by mixing a mixture of unsaturated monomers mainly composed of methyl methacrylate and a plasticizer. A known polymerization initiator such as azobisisobutyronitrile is added to the syrup in order to polymerize and cure unsaturated monomers mainly composed of methyl methacrylate.
[0015]
Moreover, this syrup can also dissolve and contain a methyl methacrylate polymer. Furthermore, this syrup may contain known additives such as antioxidants, ultraviolet absorbers, polymerization inhibitors, chain transfer agents, mold release agents, flame retardants, dyes, pigments, inorganic fillers as necessary. Agents, reinforcing agents and the like can also be added.
[0016]
The obtained syrup is defoamed under reduced pressure as necessary, and then injected into a cell composed of at least two opposing flat plates and a sealing material that seals the periphery so that the syrup does not leak.
As the material for the two opposing flat plates, metals such as glass and stainless steel are generally used. The flat plate may be a continuous belt.
[0017]
After the syrup is poured into the cell, the surroundings are sealed, followed by syrup polymerization.
The polymerization may be carried out by a known method according to the previously added polymerization initiator. Examples of the method include a method of photopolymerization by irradiating ultraviolet rays, a method of heating by a method such as placing a cell in a hot air drying furnace or a water bath, and a method of performing thermal polymerization, but are not limited thereto. is not.
After completion of the polymerization, the two opposing flat plates are removed to obtain an acrylic plate.
[0018]
【The invention's effect】
The acrylic plate of the present invention is excellent in hard material driving property, and cracks are hardly generated even when nails or screws are driven.
[0019]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to this.
In addition, the evaluation of hard material driveability was conducted by measuring the cracks when 5 iron nails with a diameter of 1.5 mm at 23 ° C. were placed in a straight line at 5 mm intervals on an acrylic plate having a size of 50 × 50 mm and a thickness of 5 mm. Evaluation was made based on the presence or absence of occurrence.
[0020]
Example 1
400 g of methyl methacrylate was placed in a 500 ml round bottom flask, and 0.004 g of azobisisobutyronitrile was added and dissolved as a polymerization initiator. This flask was immersed in an oil bath at 80 ° C. and heated, polymerized for 2 hours, and then cooled to room temperature to obtain a partially polymerized acrylic syrup.
In a separate round bottom flask, 350 g of this acrylic syrup and 150 g of acetyltributyl citrate were added and stirred and mixed until uniform. Furthermore, 0.05 g of azobisisobutyronitrile was added as a polymerization initiator, dissolved by stirring, and then defoamed under reduced pressure.
[0021]
Using a float glass with a size of 30 × 30 mm and a thickness of 1 cm and a tube made of vinyl chloride, a cell having a gap of about 6 mm between the glass plates was produced, and the bubble was defoamed into the cell. Acrylic syrup was poured and the cell mouth was sealed so that no air bubbles remained inside.
This cell was immersed in warm water at 60 ° C. and polymerized for 5 hours. Further, it was placed in a 120 ° C. hot air drying furnace for 2 hours, slowly cooled to room temperature, and the glass was removed to obtain an acrylic plate.
The obtained acrylic plate was colorless and transparent, had no stickiness on the surface, and had a good appearance.
When the nail test was carried out, no cracks were observed.
[0022]
Example 2
Instead of 350 g of partially polymerized acrylic syrup, an acrylic syrup in which 75 g of methyl methacrylate polymer (Sumipex MHF manufactured by Sumitomo Chemical Co., Ltd.) was dissolved in 300 g of methyl methacrylate was used, and the addition amount of acetyltributyl citrate was 125 g. Obtained an acrylic plate in the same manner as in Example 1.
The obtained acrylic plate was colorless and transparent, had no stickiness on the surface, and had a good appearance.
When the nail test was carried out, no cracks were observed.
[0023]
Example 3
Similar to Example 1, except that 300 g of partially polymerized acrylic syrup obtained in the same manner as in Example 1, 0.3 g of ethylene glycol dimethacrylate as the copolymerizable unsaturated monomer, and 200 g of dibutyl phthalate were used. An acrylic board was obtained.
The obtained acrylic plate was colorless and transparent, had no stickiness on the surface, and had a good appearance.
When the nail test was carried out, no cracks were observed.
[0024]
Comparative Example 1
An acrylic plate was obtained in the same manner as in Example 1 except that 450 g of partially polymerized acrylic syrup obtained in the same manner as in Example 1 and 50 g of acetyltributyl citrate were used.
The obtained acrylic plate was colorless and transparent and had a good appearance without stickiness on the surface.
However, when the nailing test was performed, a crack was generated and the plate was broken into two.
[0025]
Comparative Example 2
An acrylic plate was obtained in the same manner as in Example 1 except that 230 parts by weight of partially polymerized acrylic syrup obtained in the same manner as in Example 1 and 270 parts by weight of acetyltributyl citrate were used.
The obtained acrylic plate was colorless and transparent and had a moist surface, and was flexible to such an extent that it could not stand on its own.
When the nail test was carried out, no cracks were observed.

Claims (2)

An acrylic plate for placing a hard material, comprising a resin composition containing 50 to 85% by weight of a methyl methacrylate polymer and 15 to 50% by weight of a plasticizer selected from acetyltributyl citrate and dibutyl phthalate . 2. A hard material casting according to claim 1, wherein a syrup mainly composed of methyl methacrylate is mixed with a plasticizer selected from acetyltributyl citrate and dibutyl phthalate , and the mixture is poured into a mold and polymerized. Method for manufacturing acrylic board.