JPH09296090A - Flame-retardant methacrylic resin composition - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To develop a flame-retardant methacrylic resin having excellent flame retardancy, heat resistance, and weather resistance and capable of preventing metal corrosion. SOLUTION: Methyl methacrylate-based resin (A) 10
2 to 40 parts by weight of a halogen-containing phosphate compound (B) and 0.01 parts of a tin compound (C) based on 0 part by weight
˜1.0 parts by weight.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant methacrylic resin composition.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resin containing methyl methacrylate as a main component is
It is transparent and has excellent weather resistance, and because it has relatively well-balanced performance in terms of mechanical strength, thermal properties and molding processability, it can be used for lighting materials, optical materials, signboards,
It is used in many applications such as displays, decorative materials, and building materials. However, since the methacrylic resin has a property of being relatively easily combusted, its intended use is often limited.

Therefore, many attempts have been made to improve the flame retardancy of methacrylic resins. For example, Japanese Patent Application Laid-Open No. 61-141759 discloses that an inorganic compound such as magnesium hydroxide, aluminum hydroxide or magnesium carbonate is mixed with a methacrylic resin. However, although this method can improve the flame retardancy to some extent, it has a drawback that the methacrylic resin obtained becomes opaque and the transparency, which is the original characteristic of the methacrylic resin, is lost.

On the other hand, as a method for imparting flame retardancy without impairing the excellent transparency of methacrylic resin, for example, Japanese Patent Application Laid-Open No. 59-41349 discloses an organic halogen phosphorus compound such as a halogen-containing condensed phosphoric acid ester. Disclosed is a method of using a flame retardant based compound. Further, a method of using a phosphorus-containing compound and a halogen-free flame retardant for flame retardation of a methacrylic resin (Japanese Patent Application Laid-Open No. 5-170996).
However, halogen-based compounds are superior in flame retardancy.

However, when a halogen-based flame retardant is used to obtain a flame-retardant methacrylic resin, the halogen-based flame retardant is decomposed at the time of its production to cause corrosion of the manufacturing equipment. For example, in the production of methylmethacrylate resin molded plate, a metal stainless steel plate is used as a mold, but stainless steel is a material that easily forms a passive film against acid and is relatively resistant to corrosion. However, there is a drawback in that when a halogen-based substance such as chlorine or chlorine ions coexists, corrosion such as pitting corrosion occurs. Corrosion of the mold tends to be further promoted by heat generated by polymerization in the resin manufacturing process, external heating, or thermal decomposition or hydrolysis of the halogen-containing phosphate ester due to water present in the resin raw material or on the mold surface. Show.

Further, the use of the halogen-based flame retardant may cause corrosion of the cylinder or die due to thermal decomposition of the flame retardant not only during the above-mentioned polymerization but also during processing of the obtained resin. For example, JP-A-2-284954
The publication discloses the use of a halogen-based flame retardant, which does not easily cause corrosion, as a countermeasure against corrosion by the halogenated flame retardant.

However, the use of a halogenated flame retardant which is unlikely to cause metal corrosion has the drawback that the flame retardant effect is not sufficient and the physical properties and weather resistance are lowered, which limits the field of use. is there.

[0008]

In view of the above situation, the present inventors have excellent flame retardancy, heat resistance and weather resistance,
As a result of extensive studies aimed at obtaining a methacrylic resin capable of preventing metal corrosion, a halogen-containing phosphoric acid ester-based compound was used to obtain a flame-retardant methylmethacrylate-based resin It has been found that the above object can be achieved by blending the above-mentioned compound, and the present invention has been completed.

That is, in the present invention, 2 to 40 parts by weight of the halogen-containing phosphate compound (B) and 0.01 to 1.0 parts of the tin compound (C) are used with respect to 100 parts by weight of the methyl methacrylate resin (A). A flame-retardant methacrylic resin composition containing parts by weight.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The methyl methacrylate resin (A) used in the present invention is a homopolymer of methyl methacrylate or a copolymer of methyl methacrylate and another monomer copolymerizable with methyl methacrylate. It is united. Specific examples of other monomers copolymerizable with methyl methacrylate include alkyl methacrylates such as ethyl methacrylate and butyl methacrylate, alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate, and functional groups such as methacrylic acid and glycidyl methacrylate. Having a monomer, a monomer having two or more unsaturated double bonds in the molecule such as ethylene glycol dimethacrylate, an N-substituted maleimide monomer such as cyclohexylmaleimide, maleic anhydride or a styrene monomer Body, and polyfunctional allyl compounds having two or more allyl groups in the molecule.

Among these monomers copolymerizable with methyl methacrylate, polyfunctional allyl compounds having two or more allyl groups in the molecule reduce the burning rate of the resin and produce a small amount of halogen-containing phosphate compound. When used, the desired flame retardant effect can be exhibited.

Specific examples of the polyfunctional allyl compound include diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl isocyanurate, triallyl cyanurate, diallyl maleate, triallyl trimellitate, diethylene glycol bisallyl carbonate. , Diallyl diphenate, polyallyl glycidyl ether and the like. Of these, triallyl isocyanurate and triallyl cyanurate are particularly preferably used.

The amount of the other monomer copolymerizable with methyl methacrylate is the methyl methacrylate resin (A).
It is usually used in the range of 30% by weight or less. Especially when the polyfunctional allyl compound is used, the amount used is usually 2 to 1 with respect to 100 parts by weight of the methyl methacrylate resin (A).
It is in the range of 2 parts by weight. If it is less than 2 parts by weight, it becomes difficult to reduce the combustion rate, and melting deformation or sagging of the combustion product is likely to occur during combustion, while if it exceeds 12 parts by weight, the heat resistant temperature is lowered. Further, the sum of the polyfunctional allyl compound and the halogen-containing phosphate compound (B) is the methyl methacrylate resin (A) 1
Use of 24 parts by weight or less with respect to 00 parts by weight is preferable from the viewpoint of heat resistance. If it exceeds 24 parts by weight, the heat-resistant temperature becomes too low to be practical.

The halogen-containing phosphate compound (B) used in the present invention contains a halogen element such as chlorine or bromine in its structural unit in phosphate, polyphosphate, phosphonate, polyphosphonate and the like. To do. Specifically, halogen-containing phosphates such as tris (chloroethyl) phosphate and tris (dichloropropyl) phosphate;
CR504, a flame retardant for Daihachi Chemical Industry Co., Ltd. products
(Halogen-containing polyphosphate), polyphosphate such as CR509 (halogen-containing polyphosphonate), polyphosphonate and the like can be mentioned. These can be used alone or in combination of two or more.

The amount of the halogen-containing phosphate compound (B) used is usually in the range of 2 to 40 parts by weight, preferably 3 to 30 parts by weight, based on 100 parts by weight of the methyl methacrylate resin (A). It is a range of parts. If it is less than 2 parts by weight, the flame retardant effect is lowered, and if it exceeds 40 parts by weight, the heat resistant temperature is lowered.

The tin-based compound (C) used in the present invention is an organic tin compound such as laurate-based, maleate-based, or mercaptide-based dibutyl or dioctyl. Specific examples include dibutyltin malate, dioctyltin malate, di-n-octyltin-S, S '.
-Bis (isooctyl mercaptoacetate), dibutyltin dilaurate and the like. These compounds may be used alone or in combination of two or more.

The amount of the tin compound (C) used is in the range of 0.01 to 1.0 part by weight based on 100 parts by weight of the methyl methacrylate resin (A). If it is less than this range, the effect of preventing corrosion of the metal against the decomposition of halogen-containing phosphoric acid ester compounds decreases, while if the amount used is too large, the flame retardancy and transparency decrease. And so on.

The method for obtaining the flame-retardant methacrylic resin composition of the present invention is not particularly limited. For example, methyl methacrylate, a mixture of methyl methacrylate and another monomer copolymerizable therewith or syrup, After adding a halogen-containing phosphate compound, a tin compound and a polymerization initiator and mixing them, a mold made of inorganic glass or a metal material such as stainless steel or aluminum and, in some cases, for preventing leakage of raw materials A preferable method is a method of injecting into a mold (cell) configured with suitable sealing and polymerizing at a temperature of room temperature to 150 ° C. At this time, the polymerization temperature may be changed in multiple stages for the polymerization.

The polymerization initiator used in the present invention includes
A radical polymerization initiator generally used for the polymerization of methyl methacrylate can be used. Particularly preferred is a polymerization initiator having a 10-hour half-life temperature in the range of 35 ° C to 80 ° C. Examples of such a polymerization initiator include lauroyl peroxide, benzoyl peroxide, tertiary butyl peroxypivalate, tertiary butyl peroxy neodecanoate, tertiary butyl peroxy-2-.
Ethyl hexanoate, tert-butyl peroxyisobutyrate, tert-hexyl peroxypivalate, isopropyl peroxydicarbonate, di-2-
Organic peroxide initiators such as ethylhexyl peroxydicarbonate; 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate,
2,2'-azobis (2-methylbutyronitrile),
Examples thereof include azobis initiators such as 2,2'-azobis (2,4-dimethylvaleronitrile) and 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile).

The amount of the polymerization initiator used is 100
It is in the range of 0.001 to 1.0 parts by weight with respect to parts by weight.

In polymerization or shaping of the flame-retardant methacrylic resin composition of the present invention, if necessary, a releasing agent, an ultraviolet absorber, a light stabilizer, a coloring agent capable of maintaining transparency, an organic or inorganic filler. Etc. may be added.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Reference Examples, but the present invention is not limited thereto. Parts in Examples and Comparative Examples indicate parts by weight. Further, the evaluation of physical properties in Examples and Comparative Examples was carried out by the methods described below.

(1) Combustion characteristics A horizontal combustion test was conducted in accordance with JIS K-6911.
The horizontal burning velocity was measured while observing the burning behavior. In addition, the flammability was examined by the method of Iron Transport No. 81 of the Ministry of Transport.

(2) Heat resistance The deflection temperature under load was measured according to JIS K7207.

(3) Accelerated exposure test Using a Sunshine Weather Meter manufactured by Suga Test Instruments Co., Ltd., an accelerated exposure test was conducted under the conditions of a black panel temperature of 63 ° C. and a 12-minute rainfall during a 60-minute cycle. The ΔYI value was measured after 600 hours.

[Examples 1 and 2, Comparative Example 1] 3000 parts of methyl methacrylate were placed in a separable flask equipped with a cooling tube, a thermometer and a stirrer, the atmosphere was replaced with nitrogen, and the mixture was heated with stirring. When the internal temperature reached 80 ° C., 1.95 parts of 2,2′-azobis- (2,4-dimethylvaleronitrile) was added as a polymerization initiator. The mixture was further heated and kept at an internal temperature of 95 ° C for 15 minutes and then cooled to room temperature to obtain a syrup having a viscosity of 10 poise at 20 ° C and a polymerization rate of 20%. Then this syrup 1
Triallyl isocyanurate (TAI
4.4 parts by weight of C) and 5.5 parts of CR509 (halogen-containing polyphosphonate, manufactured by Daihachi Chemical Industry Co., Ltd.) were added and mixed.

Next, TVS8 was added to 300 parts of this liquid mixture.
831 (di-n-octyltin-S, S'-bis (isooctylmercaptoacetate), manufactured by Nitto Kasei Co., Ltd.)
Are added and mixed in the amounts shown in Table 1, and again, 0.195 parts of 2,2'-azobis- (2,4-dimethylvaleronitrile) as a polymerization initiator and 0 parts of sodium dioctylsulfosuccinate as a release agent are added. 0.015 parts, and 0.3 parts of 2- (5-methyl-2-hydroxyphenyl) benzotriazole as an ultraviolet absorber were added and mixed and dissolved. Next, this mixture was sucked and degassed, and a stainless steel plate (SUS304, 30c) having one surface mirror-polished
m × 30 cm × 3 mm (thickness)) and a polyvinyl chloride gasket, and poured into a casting mold for 8
Polymerization was carried out for 60 minutes in a 0 ° C. water bath and for 1 hour in a 130 ° C. air bath to obtain a colorless transparent resin plate having a thickness of 3 mm. The evaluation results of this resin plate are shown in Table 1.

[0028]

[Table 1]

[Comparative Example 2] 4.7 parts by weight of TAIC, 9.4 parts of triphenyl phosphate and 3.0 parts of o-dichlorobenzene were added and mixed with 100 parts of syrup of Example 1. Then, in the same manner as in Example 1, a polymerization initiator, a release agent and an ultraviolet absorber were mixed with 300 parts of this liquid mixture. Hereinafter, the same operation as in Example 1 was performed to obtain a colorless transparent resin plate having a thickness of 3 mm. The chlorine content and phosphorus content in the resin were almost the same as in Example 1. Next, when the physical properties of this resin plate were evaluated, the horizontal burning rate was good at 10.8 mm / min, but the deflection temperature under load was as low as 68 ° C. Further, ΔYI after 600 hours of the accelerated exposure test was as high as 6.1, and yellowing was remarkable.

[Examples 3 to 6 and Comparative Examples 3 to 4] Example 1
In, except that TVS8831 was used instead of the tin compound shown in Table 2, the same operation as in Example 1 was repeated to obtain a colorless transparent resin plate having a thickness of 3 mm. Table 2 shows the evaluation results of the obtained resin plate.

[0031]

[Table 2]

[Examples 7 to 10, Comparative Examples 5 to 6] TAIC and CR509 were added and mixed in amounts shown in Table 3 per 100 parts of the syrup of Example 1. Next, to 3000 parts of this liquid mixture, 1.5 parts of TVS8831 and 0.24 part of 2,2'-azobis- (2,4-dimethylvaleronitrile) as a polymerization initiator were added, and as a releasing agent. 0.15 parts of sodium dioctyl sulfosuccinate and 3.0 parts of 2- (5-methyl-2-hydroxyphenyl) benzotriazole as an ultraviolet absorber were added and mixed and dissolved. Then, this mixed solution is sucked and degassed, and poured into a casting mold composed of a stainless steel plate having a size of 61 cm × 48 cm × 3 mm (thickness) one side of which is mirror-polished and a polyvinyl chloride gasket, 76 ° C
Polymerization was carried out for 60 minutes in a water bath and further in an air bath at 130 ° C. for 1 hour to obtain a colorless transparent resin plate having a thickness of 2 to 10 mm. Table 3 shows the evaluation results of the obtained resin plate.

[0033]

[Table 3]

Further, as a result of conducting a flame retardancy test on materials for railway vehicles (Iron No. 81 of Ministry of Transport) for the above resin plates, the resin plates of Examples 7 to 10 showed no residual flame after alcohol combustion. It quickly extinguished itself and had the ability to be positioned as flame retardant in the material category. Further, a test was conducted in which the amount of alcohol was increased from the standard value of 0.5 cc to 1.0 cc. On the other hand, in the resin plate obtained in Comparative Example 5, combustion expanded without self-extinguishing even after alcohol combustion. Comparative Example 6
Had the ability to fall into the flame-retardant category with no afterflame after alcohol combustion, but it was not suitable for practical use due to insufficient heat resistance.

Evaluation of Corrosion of Flame Retardant to Metal: Corrosion to metal of flame retardant composed of a combination of halogen-containing phosphoric ester compound and tin compound used in flame retardant methacrylic resin composition of the present invention The following experiment was conducted.

Reference Example 1 Into a 50 ml glass sample bottle, the immersion liquid shown in Table 4 below was placed, and the same stainless steel plate as one used in Example 1 was mirror-finished. Test piece manufactured from (material SU
(S304, size 20 mm × 40 mm) was placed so that about half of it was immersed in the immersion liquid. After that, these sample bottles were left at a temperature of 60 ° C. for 100 to 140 days, and then the appearance change of the test piece was observed. Table 4 shows the obtained results. As is clear from this result, metal corrosion occurs only with the halogen-containing phosphoric acid ester compound, but metal corrosion is suppressed when the tin compound of the present invention coexists.

[0037]

[Table 4]

[Reference Example 2] In this Reference Example 2, the effect in the presence of phosphoric acid and an alkyl halide, which are the raw materials constituting the halogen-containing phosphate ester compound, was examined. This can be regarded as an accelerated test in which the decomposition of the halogen-containing phosphate compound is advanced. The same operation as in Reference Example 1 was repeated except that the composition of the immersion liquid was as shown in Table 5 and the immersion period was 4 weeks. Table 5 shows the results. It can be seen that the corrosion occurs only with the liquid C, but the metal corrosion is suppressed by coexisting with the tin compound of the present invention.

[0039]

[Table 5]

[0040]

Since the flame-retardant methacrylic resin composition of the present invention uses a tin compound, a metal mold or a halogen-containing phosphoric ester compound is decomposed during the production or processing of the tin compound. It is possible to prevent mold corrosion. Furthermore, the flame-retardant methacrylic resin composition of the present invention is excellent in flame retardancy, weather resistance, and heat resistance, and is used for various lighting covers, guide lights, signboards, sound insulation plates, building materials, low-power equipment and OA equipment. It can be used for artificial marble, etc.

Claims (1)

[Claims] 1. A methyl methacrylate resin (A) 10
2 to 40 parts by weight of the halogen-containing phosphate compound (B) and 0.0 of the tin compound (C) based on 0 part by weight.
A flame-retardant methacrylic resin composition containing 1 to 1.0 part by weight.