JPH06100709A - Acrylic resin sheet for preventing scattering and its production - Google Patents

Abstract

PURPOSE:To obtain an acrylic resin sheet for preventing scattering with hardly any scattering of fragments in impact fracture by coating polyamide fiber with a specific phosphoric acid ester, embedding the coated polyamide fiber in methyl (meth)acrylate (partial polymer thereof), polymerizing and curing the methyl methacrylate. CONSTITUTION:The acrylic resin sheet for preventing scattering is obtained by immersing polyamide fiber in a 1-50wt.% solution of (A) a compound expressed by the formula [(n) is an integer of 1-6; R is H or methyl] [preferably mono(2-methacryloyloxyethyl)acid phosphate], etc., arranging the resultant polyamide fiber coated with the compound on the surface in a mold for polymerization, then casting (B) methyl methacrylate or its partial polymer and a radical polymerization initiator (e.g. benzoyl peroxide), polymerizing and curing the methyl methacrylate or its partial polymer at ambient temperature to 140 deg.C. A method for using two opposite acrylic resin sheets as the mold for the polymerization, fixing the polyamide fiber with a tacky flexible thick-wall tape in sealing the periphery, then polymerizing and curing the methyl methacrylate, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic resin sheet which causes less scattering of fragments at the time of impact destruction.

[0002]

2. Description of the Related Art There is known a technique for preventing scattering of fragments when glass is broken due to impact by burying metal fibers or metal wires in an inorganic glass in parallel or in a mesh shape. It is popular. On the other hand, embedding metal fibers or chemical fibers in a transparent resin sheet such as an acrylic resin sheet which is easily damaged is disclosed in, for example, JP-A-47-5.
It is known in Japanese Patent No. 535, Japanese Utility Model Publication No. 1-156931, and the like.

Embedding a metal fiber in a transparent resin sheet is unfavorable in appearance because the workability of the sheet, particularly the cutting method, is restricted, and the fiber is conspicuous because the fiber is opaque. In this respect, in the case of a transparent resin sheet, chemical fibers, for example, transparent monofilaments of polyamide, polyester, polypropylene and the like are advantageous.

On the other hand, as a general method for producing an acrylic resin sheet which is a representative of organic glass, there is a template polymerization method in which methyl methacrylate is polymerized in the gap between opposed flat plates. This template polymerization method is generally a method in which two sheets of inorganic glass are made to face each other and the periphery is sealed with a soft gasket, a mold is made, methyl methacrylate and a small amount of a polymerization initiator are added, polymerization is performed, and then the template is taken out of the template. . In order to produce the anti-scattering acrylic resin sheet by this method, it is possible to make a mold in which fibers are arranged in a flat plate facing each other by some method, inject a resin raw material into the mold and cure it to integrate the fibers. it can.

[0005]

However, according to the study of the present inventors, when the polyamide fiber is embedded and polymerized during the template polymerization, the peeling is considered to be due to the weak adhesion between the polyamide fiber and methyl methacrylate. It has been found that the peeled portion has a problem in that external light is likely to be scattered and conspicuous so that the appearance is bad and visibility is deteriorated.

[0006]

The inventors of the present invention have made diligent studies to solve the above-mentioned problems, and as a result, when producing a shatterproof acrylic resin sheet having a plurality of polyamide fibers arranged therein, the polyamide fibers are previously prepared. It was found that the peeling can be prevented by using a polyamide fiber coated with a specific compound on the surface of, and a shatterproof acrylic resin sheet with good visibility can be provided, and the present invention has been completed. It was. That is, the present invention has the following general formula

[0007]

[Chemical 3]

The present invention relates to a shatterproof acrylic resin sheet having a plurality of polyamide fibers coated with a compound represented by the formula, and a method for producing the same.

Examples of the compound represented by the above general formula include mono (2-methacryloyloxyethyl) acid phosphate, mono (2-acryloyloxyethyl) acid phosphate, and acid phosphooxypolyoxyethylene having 2 to 6 repeating units of ethylene oxide. Glycol monomethacrylate (or acrylate) or the like, and a combination thereof may be used. These have a monoester structure of phosphoric acid, but may be a mixture of monoester and diester. If the repeating unit of ethylene oxide becomes too large, the expected adhesiveness cannot be obtained. Preferred is mono (2-methacryloyloxyethyl) acid phosphate. The polyamide fiber in the present invention is, for example, a monofilament of 6-nylon or a copolymer nylon of 6-nylon and 6,6 nylon, but is not particularly limited thereto.

As an example of the method for applying to the polyamide fiber, there is a method in which the fiber is dipped in a liquid or solution of the above compound, wetted, and then taken out. If the coating amount is too small, peeling will occur after polymerization. On the other hand, excessive coating may cause the surface of the polyamide fiber to be whitened after polymerization, or the adhesion to the base material may be too strong, and the fiber may be cut off without peeling from the base material at the time of impact breakage of the sheet. Therefore it is better to avoid it. Therefore, it is preferable to use a 1 to 50% by weight solution of the compound, more preferably 3 to 20%.
% By weight. As a solvent for the solution, a combination of an acid, an alcohol, a ketone, and a hydrocarbon can be used as a solvent for dissolving the compound. Considering the chemical resistance of the polyamide fiber, it is preferable to avoid making the immersion treatment time extremely long when methanol, phenol or the like is used.

For the purpose of controlling the speed at which the fibers are drawn out of the solution so that the coating can be carried out uniformly, and for the purpose of adjusting the drying speed of the solvent, a combination of solvents that is suitable for the drawing speed of the fibers and the drying atmosphere temperature is selected. Known methods can be used. For the same purpose, a solid content such as polymethylmethacrylate may be added to the coating solution. As other coating methods, spray coating, curtain coater coating, brush coating and the like can be used.

Polyamide fiber coated with the above compound is
In order to arrange it in the approximate center in the thickness direction of the obtained sheet, the fiber is arranged in the center of the gap of the mold when the mold for polymerization is prepared in advance, and methyl methacrylate or its partial polymer and the radical polymerization initiator are poured and polymerized. By solidifying, an acrylic resin sheet in which polyamide fibers are embedded and integrated in an acrylic resin sheet can be produced.

In particular, two acrylic resin sheets are used instead of the two facing inorganic glasses as a mold for polymerization, and when the periphery is sealed, an adhesive soft pressure tape is used to spread the fibers on the opposite sides. After that, the method of fixing with the tape is preferable because sealing and fixing of the fibers can be performed at the same time. Further, in this case, two acrylic resin sheets are adhered and integrated by polymerizing and solidifying methyl methacrylate or a partial polymer thereof which is poured into the mold gap, and the fibers can be arranged at approximately the center in the thickness direction of the integrated sheet. Therefore, it is the most preferable method.

The methyl methacrylate or its partial polymer in the present invention is known as a raw material in the production of an acrylic resin sheet by template polymerization, but other than this, methyl acrylate and butyl can be used as a compound copolymerizable with methyl methacrylate. Lower alkyl acrylates such as acrylates, N-substituted maleimides, styrene, aromatic vinyl compounds such as α-methylstyrene,
1,6-hexanediol diacrylate (or dimethacrylate), neopentyl glycol diacrylate (or dimethacrylate), tripropylene glycol diacrylate (or dimethacrylate), trimethylolpropane triacrylate (or dimethacrylate), tetramethylolpropane A compound having two or more unsaturated double bonds in one molecule such as triacrylate (or dimethacrylate) can be used in a range such that the weight ratio thereof is smaller than that of methyl methacrylate which is the main raw material.

As the radical polymerization initiator used in the present invention, a radical polymerization initiator generally used for the polymerization of methyl methacrylate can be used. For example, as an organic peroxide-based initiator, lauroyl peroxide, benzoyl peroxide, t-butyl peroxypivalate, t-butyl peroxy neodecanoate, t-butyl peroxy-2-ethylhexanoate, t -Butyl peroxyisobutyrate, diisopropyl peroxy dicarbonate, di-2-ethylhexyl peroxy dicarbonate and the like. As the azobis-based initiator, 2,2'-azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, 2,2'-azobis (2-methylbutyronitrile), 2 , 2'-azobis (2,4-dimethylvaleronitrile), 2,2'-
Examples include azobis (4-methoxy-2,4-dimethylvaleronitrile).

The polymerization temperature conditions may be those known in template polymerization of acrylic resin sheets, and the polymerization may be carried out in the range of room temperature to 140 ° C., and the polymerization temperature may be changed to carry out multi-stage polymerization.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples.

Example 1 To 475 g of methanol, 25 g of mono (2-methacryloyloxyethyl) acid phosphate was added and dissolved by stirring to obtain a coating solution. A 6-nylon monofilament (having a diameter of about 1 mm) was immersed in this solution, taken out, and naturally dried at room temperature for about 5 minutes. Immersion time is 5 seconds, 1 minute, 3
It was shaken in 5 steps of minutes, 30 minutes and 60 minutes. Next, a 17 cm square acrylic resin sheet (Acrylite manufactured by Mitsubishi Rayon Co., Ltd., 8 mm thick) was made to face each other, and a soft gasket made of vinyl chloride was sandwiched so as to seal the periphery to obtain a polymerization cell. At that time, the above-mentioned dip-coated 6 nylon monofilaments were arranged in the gaps inside the cell in parallel with 20 mm intervals.

Next, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) was added to 100 g of a methyl methacrylate partial polymer having a polymerization rate of 8% and a viscosity of 80 cps.
0.2 g and 0.5 g of water were mixed and dissolved, and then the mixture was injected into the gap inside the polymerization cell so that the adhesive thickness after polymerization was about 2 mm. The mixture was left standing at room temperature (about 23 ° C.) for 1 day to polymerize. The two acrylic resin sheets were adhered after polymerization, and the filaments were embedded in the adhesive layer to be integrated.

Five types of sheets prepared by changing the dipping time were placed in a low temperature chamber (-15 ° C) and a high temperature chamber (70 ° C) for 2 hours and then taken out and observed, but none of the filaments were peeled off.

Next, each of these five types of sheets was cut into strips so that one filament could be inserted into each of the sheets, and then both sides were supported, and a shock was applied to the center by a hammer. Although it was broken into pieces, the filament was not cut and two pieces were held together, confirming the scattering prevention performance.

Example 2 To 475 g of acetone, 25 g of mono (2-methacryloyloxyethyl) acid phosphate was added and dissolved by stirring to obtain a coating solution. Staying in this solution tank for about 1.5 seconds,
A 6-nylon monofilament was immersed and passed at a moving speed of about 8 cm / sec, and excess liquid was wiped off with gauze and then naturally dried. The same operation as in Example 1 was carried out except that this filament was used to obtain a sheet in which the filament was embedded.

Although the filaments were left at a low temperature and a high temperature in the same manner as in Examples 1 to 5, the filaments were not peeled off and the good appearance was maintained. Furthermore, the filament was not broken in the hammer impact test, and the two fragments were held together.

Comparative Example 1 The procedure of Example 1 was repeated except that the surface of the 6-nylon monofilament was not subjected to any treatment to prepare a sheet in which filaments were embedded. However, most of the filaments are peeled from the base material, and the peeled portions appear to shine due to external light, which is unfavorable in appearance.

[0025]

The anti-scattering acrylic resin sheet of the present invention has an excellent balance of the adhesive strength between the embedded polyamide fiber and the substrate, and does not peel off even when a severe outdoor temperature change occurs, resulting in a good appearance. While maintaining visibility, the fibers are less likely to break during impact breakage, and are also effective in retaining fragments. This sheet can be widely used as a safety window or fence for sports facilities, or as a sound insulation wall.

Claims (2)

[Claims] 1. A surface of the following general formula: A shatterproof acrylic resin sheet in which a plurality of polyamide fibers coated with a compound represented by are arranged inside. 2. A surface of the following general formula: A method for producing a shatterproof acrylic resin sheet, which comprises embedding polyamide fibers coated with a compound represented by the formula (3) in methyl methacrylate or a partial polymer thereof and polymerizing and curing the same.