JPH09302191A - Methacrylic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a methacrylic resin composition, comprising a specific methyl methacrylate-based resin and a phosphoric ester-based compound in a specific proportion, excellent in flame retardance, weatherability and heat resistances without causing fire dripping when burning and useful for various lighting covers, sound insulating plates, etc. SOLUTION: This methacrylic resin composition comprises (B) 2-18 pts.wt. phosphoric ester-based compound such as a halogenated phosphoric ester condensate or triphenyl phosphate in (A) 100 pts.wt. methyl methacrylate-based resin composed of (A1 ) 98-88wt.% methyl methacrylate unit and (A2 ) 2-12wt.% polyfunctional allyl compound unit such as allyl (iso)cyanurate. The composition is prepared so as to provide <=24 pts.wt. total amount of the components A2 and B based on 100 pts.wt. component A1 .

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a methacrylic resin composition, and more particularly to a methacrylic resin composition which is flame retardant, and has excellent weather resistance and heat resistance.

[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 members, 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, this method has the drawback that the methacrylic resin obtained becomes opaque although the flame retardancy is improved to some extent, and the transparency, which is the original characteristic of the methacrylic resin, is lost.

A method for imparting flame retardancy without impairing the excellent transparency of methacrylic resin is disclosed in, for example, JP-A-59.
No. 41349 discloses a method of using a flame retardant of an organic halogen phosphorus compound such as a halogen-containing condensed phosphoric acid ester. However, when the above-mentioned halogen-containing flame retardant is used, it has the drawbacks that a toxic gas of halogen is generated at the time of combustion, corrosiveness to metals and fire dripping occur at the time of combustion.

On the other hand, it is known to use a phosphorus compound for flame retarding a methacrylic resin that does not contain halogen atoms in its constituent materials as much as possible. For example, as a method for obtaining a non-halogen flame-retardant methacrylic resin, Japanese Patent Laid-Open No.
No. 122761 discloses the use of phenylphosphonic acid and JP-A-5-170996 discloses the use of polyphosphate. However, in these methods, it is necessary to use a large amount of a flame retardant in order to sufficiently exhibit the effect of flame retardancy, and therefore bleeding may occur during combustion, or the weather resistance may be reduced. There is a problem that its use environment is limited.

[0006]

Means for Solving the Problems As a result of intensive investigations in view of the above situation, the present inventors have found that a methylmethacrylate resin made of a copolymer of methylmethacrylate and a specific allyl compound has a specific amount of It has been found that a methacrylic resin composition which is flame-retardant, has excellent weather resistance and heat resistance by containing a phosphoric acid ester-based compound, and moreover does not easily cause fire dripping during combustion has been completed. .

That is, the present invention provides 100 parts by weight of a methyl methacrylate resin (A) comprising 98 to 88% by weight of a methyl methacrylate unit (a-1) and 2 to 12% by weight of a polyfunctional allyl compound unit (a-2). On the other hand, the component (a-2) containing 2 to 18 parts by weight of the phosphate compound (B) and 100 parts by weight of the component (a-1).
And the above component (B) is 24 parts by weight or less in total, which is a methacrylic resin composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The methyl methacrylate resin (A) used in obtaining the methacrylic resin composition of the present invention is a methyl methacrylate unit (a-1) 98-
88% by weight and polyfunctional allyl compound unit (a-2) 2-1
It is a copolymer composed of 2% by weight. Polyfunctional allyl compound unit (a-2) in methyl methacrylate resin (A)
Content of less than 2% by weight makes it difficult to reduce the burning rate of the resin, and melting deformation or dripping of the combustion product is likely to occur during combustion, while if it exceeds 12 parts by weight, the heat-resistant temperature decreases. Like

In the present invention, the polyfunctional allyl compound (a-2) used to form the methyl methacrylate resin (A) is a compound having two or more allyl groups in the molecule. Specific examples of the polyfunctional allyl compound include, for example, 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. Particularly preferred are triallyl isocyanurate and triallyl cyanurate.

The phosphoric acid ester compound (B) used in obtaining the methacrylic resin composition of the present invention is a phosphate, polyphosphate, phosphonate, polyphosphonate, or chlorine or bromine in the structural unit thereof. Those containing such a halogen element can be used. Specifically, non-halogen phosphates such as triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate; tris (chloroethyl)
Examples thereof include halogen-containing phosphoric acid esters such as phosphate and tris (dichloropropyl) phosphate. Further, as polyphosphates and polyphosphonates, for example, CR504, C which is a product of Daihachi Chemical Industry Co., Ltd.
Condensate of halogenated phosphoric acid ester such as R509, CR7
Aromatic condensed phosphates such as 335 and CR741C, and ADEKA STAB P, a product of Asahi Denka Co., Ltd.
FR (bis (1,3-phenylene diphenyl) phosphate) etc. are mentioned. Preferred phosphoric acid ester compounds include triphenyl phosphate and CR509.
Is mentioned.

These compounds can be used in combination, but the amount of each of the above-mentioned compounds to be mixed depends on the purpose of use. For example, a non-halogen phosphate ester is used for the purpose of slowing down the burning rate to prevent the spread of fire during a fire, and a halogen-containing phosphorus ester to prevent the resin surface from igniting and to impart self-extinguishing properties. Preference is given to using acid esters. The use of a non-halogen phosphate ester makes it possible to obtain a methacrylic resin composition having a horizontal burning rate of 20 mm / min or less and a deflection temperature under load of 70 ° C. or higher as defined by JIS standard. On the other hand, the halogen-containing phosphoric acid ester can impart desired properties without lowering other physical properties as compared with the non-halogen phosphoric acid ester.

The amount of the phosphate compound (B) used is 100 parts by weight of the methyl methacrylate resin (A) composed of the methyl methacrylate unit (a-1) and the polyfunctional allyl compound unit (a-2). Usually, it is in the range of 2 to 18 parts by weight. If it is less than 2 parts by weight, the flame retardant effect is lowered and the resin surface is easily ignited, and if it exceeds 18 parts by weight, the heat resistant temperature is lowered.

However, the phosphoric acid ester compound (B)
Is used in the above range for the methyl methacrylate resin (A), but the polyfunctional allyl compound unit (a-
2) and the total amount of the phosphate compound (B) are 2 with respect to 100 parts by weight of the methyl methacrylate unit (a-1).
It is preferable to add 4 parts by weight or less. This is because when the total amount of the polyfunctional allyl compound unit (a-2) and the phosphoric acid ester compound (B) exceeds the above range, the heat resistance of the obtained resin is lowered.

The method for obtaining the methacrylic resin composition of the present invention is not particularly limited. For example, a polyfunctional allyl compound, a phosphoric ester compound and a polymer are added to methyl methacrylate or a mixture of a methyl methacrylate polymer and methyl methacrylate. After adding and mixing the initiator, in a mold composed of a mold made of inorganic glass, or a metal material such as stainless steel or aluminum and, in some cases, a suitable sealing material for preventing leakage of polymerization raw materials. It is preferable to use a method of injecting into the solution 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),
2,2'-azobis (2,4-dimethylvaleronitrile) and 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) azobis initiators may be mentioned.

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 the polymerization of the methacrylic resin composition of the present invention, a release agent, an ultraviolet absorber, a light stabilizer, a colorant, an organic or inorganic filler, etc. may be added, if necessary.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative 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. Further, a flammability test of a vehicle material specified by the method of the Ministry of Transport Iron and Steel No. 81 was conducted.

(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 to 2000 hours.

[Examples 1 and 2, Comparative Examples 1 to 3] Cooling tube,
A separable flask equipped with a thermometer and a stirrer was charged with 3000 parts of methyl methacrylate and replaced with nitrogen, and then 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%. Next, 100 parts of this syrup was added to triallyl isocyanurate (TAI).
C) and triphenyl phosphate (TPP) were added and mixed in the amounts shown in Table 1 to obtain a liquid mixture.

Next, to 300 parts of this liquid mixture was added again 0.195 parts of 2,2'-azobis- (2,4-dimethylvaleronitrile) as a polymerization initiator, and dioctylsulfosuccinic acid as a releasing agent. 0.1 sodium
5 parts and 2- (5-methyl-2- as UV absorber
0.3 part of (hydroxyphenyl) benzotriazole was added and mixed and dissolved. The mixture is then suction degassed,
Pour into a casting mold consisting of a 30 cm x 30 cm square tempered glass plate and a polyvinyl chloride gasket,
60 minutes in a water bath at 80 ° C (first stage polymerization), then 13
Polymerization was carried out for 1 hour (second-stage polymerization) in an air bath at 0 ° C. to obtain a colorless transparent resin plate having a thickness of 3 mm. Table 1 shows the evaluation results of the obtained resin plate.

[0024]

[Table 1]

As is clear from the results shown in Table 1, in Examples 1 and 2 of the present invention, good horizontal burning rate and deflection temperature under load were exhibited by using a relatively small amount of TAIC and TPP. But TAIC or TPP
In Comparative Example 1 and Comparative Example 2 in which each of them was used in a large amount alone, good horizontal burning rate and deflection temperature under load were not obtained. Regarding the combustion behavior, in Example 1, Example 2 and Comparative Example 1 in which TAIC was used, the test piece remained horizontal, and only the combustion part disappeared, but the TAIC was used. In Comparative Example 2 and Comparative Example 3 which were not used, the burning portion drooped downward, and burning of the molten resin was observed.

[Examples 3 to 4] In Example 1, the TP
PFR (Adeka Stab PFR, bis (1,3-phenylene-diphenyl) phosphate, manufactured by Asahi Denka Co., Ltd.) whose P is shown in Table 2 and CR741C (aromatic condensed phosphate ester, Daihachi Chemical Co., Ltd.) The same operation as in Example 1 was repeated except that the colorless transparent resin plate having a thickness of 3 mm was obtained. Table 2 shows the evaluation results of the obtained resin plate.

[0027]

[Table 2]

[Examples 5 to 12, Comparative Example 4] The same procedure as in Example 1 was repeated except that the allyl group-containing compound shown in Table 3 was used instead of TAIC. A 3 mm colorless transparent resin plate was obtained. Table 3 shows the evaluation results of the obtained resin plate. However, in the case of using diethylene glycol bisallyl carbonate and polyallyl glycidyl ether, it was difficult to release the resin plate from the glass plate of the mold, so use a mold in which a polyester film is attached to the inner surface of the glass plate. went.

[0029]

[Table 3]

As is clear from the results shown in Table 3, by using a polyfunctional allyl compound and copolymerizing it with methyl methacrylate, the horizontal burning rate can be made remarkably lower than that of a normal methacrylic resin. Further, regarding the combustion behavior of the resin plate, melting deformation did not occur and the tip of the combustion part was slightly bent, and the molten resin did not drop and burn.

[Examples 13 to 14] In Example 1,
The same operation as in Example 1 was repeated except that the amount of TPP was changed to CR509 (halogenated phosphoric acid ester condensate, manufactured by Daihachi Chemical Industry Co., Ltd.) in the amount shown in Table 4, and the plate thickness was 3 mm. A colorless transparent resin plate was obtained. Table 4 shows the evaluation results of the obtained resin plate.

[0032]

[Table 4]

[Embodiments 15 to 17] In Embodiment 1, 2
The same operation as in Example 1 was repeated except that the stage polymerization temperature was changed as shown in Table 5 to obtain a colorless transparent resin plate having a thickness of 3 mm. Table 5 shows the evaluation results of the obtained resin plates.
Shown in

[0034]

[Table 5]

[Examples 18 to 20, Comparative Examples 5 to 7] TAIC and CR509 were added to 100 parts of the syrup of Example 1.
And TPP were added in the amounts shown in Table 6 and mixed. Next, to 3000 parts of this liquid mixture, 2,2'-azobis-
0.24 parts of (2,4-dimethylvaleronitrile) was added, 0.15 parts of sodium dioctylsulfosuccinate as a release agent and 2- (5
3.0 parts of -methyl-2-hydroxyphenyl) benzotriazole were added and mixed and dissolved. Then, this mixture was suctioned and deaerated, and then poured into a casting mold composed of a tempered glass plate having a size of 61 cm × 48 cm and a gasket made of polyvinyl chloride, and was placed in a water bath at 76 ° C. for 60 minutes, and further at 130 ° C. Polymerization was performed in the air bath for 1 hour to obtain a colorless transparent resin plate having a thickness of 10 mm. Table 6 shows the evaluation results of the obtained resin plate.

Further, with respect to the above-mentioned resin plate, a flame retardant test of a material for a railway vehicle specified in the Ministry of Transport's Iron Transport No. 81 was conducted. In the above flame retardancy test, the case where the amount of alcohol is 0.5 cc corresponds to the prescribed method. The test results are shown in Table 6, and the judgment criteria are as shown below. ○ ... Self-extinguishing immediately without afterflame after alcohol combustion (pass) X ... Afterflame after alcohol combustion grew and combustion expanded (fail)

[0037]

[Table 6]

As is clear from the results shown in Table 6, the methacrylic resin composition according to the present invention has a good horizontal burning rate and a deflection temperature under load, and can be used as a material for railway vehicles.

[0039]

The methacrylic resin composition of the present invention having the constitution as described above is flame-retardant, has excellent weather resistance and heat resistance, and is free from dripping even during combustion.
Various lighting covers, sound insulation boards, building materials, light electrical equipment, office automation equipment,
It can be used for artificial marble.

Claims (1)

[Claims] 1. A methyl methacrylate unit (a-1) 9
8 to 88 wt% and polyfunctional allyl compound unit (a-2) 2
The amount of the phosphoric acid ester compound (B) is 2 to 18 parts by weight with respect to 100 parts by weight of the methyl methacrylate resin (A) consisting of 12 to 12% by weight, and the above component (a-
1) A methacrylic resin composition in which the total amount of the component (a-2) and the component (B) per 100 parts by weight is 24 parts by weight or less.