JPH0149179B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a flame-retardant acrylic resin composition having a high degree of flame retardancy and excellent physical properties, and a method for producing the same. More specifically, the present invention provides methyl methacrylate, α-methylstyrene, styrene,
The present invention relates to a flame-retardant acrylic resin composition having excellent physical properties comprising a quinary copolymer of maleic anhydride and methacrylic acid and a halogen-containing condensed phosphoric acid ester, and a method for producing the same. Acrylic resin is a thermoplastic resin whose main component is methyl methacrylate, and its excellent transparency, excellent weather resistance, good mechanical properties, and heat resistance make it useful for lighting materials, signboards, displays, and construction materials. Although it is widely used as a material for electrical equipment, its field of use is limited because it is a combustible material. It is already known that flame retardance can be imparted to acrylic resins by adding certain types of organic phosphate esters, but these organic phosphate esters generally have a plasticizing effect, and the resulting acrylic resin moldings It had the drawbacks of significantly lowering the heat distortion temperature and also significantly lowering the mechanical strength. In addition, the added flame retardant greatly increases the water absorption of the final composition, so when this flame retardant board is used outdoors, the sheet absorbs water and becomes deformed or crazes occur, resulting in product complaints. This often led to problems. Therefore, there is a need to reduce the amount of flame retardant added to achieve the flame retardant effect, and although many studies have been conducted in this regard, no satisfactory results have yet been obtained. . The present inventors have conducted intensive studies to improve the above-mentioned drawbacks of conventional flame-retardant acrylic resins, and as a result, they have found that they can use conventional methyl methacrylate alone or acrylic resin consisting of methyl methacrylate and methacrylic acid as a base polymer. In place of the resin, a 5-element copolymer consisting of methyl methacrylate, α-methylstyrene, styrene, maleic anhydride and methacrylic acid having a specific composition is used, and a halogen-containing condensed phosphoric acid ester is used as a flame retardant. We have discovered that by blending with acrylic resin, we can impart superior flame retardancy compared to conventional flame retardant acrylic resins.
This has led to the present invention. That is, the gist of the present invention is that 40 to 88% by weight of methyl methacrylate, 1 to 15% by weight of α-methylstyrene, 5 to 15% by weight of styrene, 5 to 15% by weight of maleic anhydride, and 1 to 15% by weight of methacrylic acid. % by weight of a copolymer and a halogen-containing condensed phosphoric acid ester, a flame-retardant acrylic resin composition characterized in that the composition contains 3 to 40% by weight of the halogen-containing condensed phosphoric acid ester, and methacrylic acid. Consists of 40-88% by weight of methyl monomer or its partial polymer, 1-15% by weight of α-methylstyrene, 5-15% by weight of styrene, 5-15% by weight of maleic anhydride and 1-15% by weight of methacrylic acid. Flame retardant, characterized in that the halogen-containing condensed phosphoric acid ester is added to a monomer mixture or a partial polymer thereof in an amount of 3 to 40% by weight and polymerized in the presence of a polymerization initiator. The present invention provides a method for producing a polyacrylic resin composition. As mentioned above, the copolymer constituting the composition of the present invention contains 40 to 88% by weight of methyl methacrylate, α-
It is obtained by copolymerizing 1 to 15% by weight of methylstyrene, 5 to 15% by weight of styrene, 5 to 15% by weight of maleic anhydride, and 1 to 15% by weight of methacrylic acid. The methacrylic acid ester component constituting the copolymer is a necessary component to maintain the optical properties, weather resistance, or mechanical properties inherent to the methacrylic resin, and its amount is 40 to 88% by weight in the copolymer. If the amount used is less than 40% by weight, the above characteristics will be lost, and if it exceeds 88% by weight, the effect of improving heat resistance and flame retardance will be reduced, which is not preferable. Further, the α-methylstyrene component constituting the copolymer is one of the components that improves the heat resistance of the obtained copolymer, and is in the range of 1 to 15% by weight, preferably 3 to 10% by weight in the copolymer. Used in a range of % by weight. If it is less than 1% by weight, heat resistance will not be sufficient,
If it exceeds 15% by weight, mechanical properties and productivity will decrease, which is not desirable. In addition, the styrene component constituting the copolymer is not a component that directly improves the heat resistance and soft flame properties of the copolymer, but it is a copolymer of α-methylstyrene and maleic anhydride, which are heat resistance improving components. It indirectly improves heat resistance by increasing the copolymerization reactivity, and at the same time has a significant effect on improving productivity, and also improves the mechanical properties, colorability, and molding processability of the resulting copolymer. It also has an extremely favorable effect on. In particular, completely unexpected effects were observed in terms of improvements in mechanical properties and coloration. Styrene needs to be used in a proportion of 5 to 15% by weight in the copolymer; if it is less than 5% by weight, productivity will be poor, and if it exceeds 15% by weight, heat resistance and optical properties will deteriorate. This is not desirable as there is a tendency to In addition, the maleic anhydride component constituting the copolymer has the effect of increasing the copolymerization reactivity of α-methylstyrene and the effect of improving the heat resistance of the copolymer through interaction with styrene. A range of ~15% by weight is required, preferably 10-15% by weight. If the proportion used is less than 5% by weight, productivity and heat resistance will be poor, and if it exceeds 15% by weight, mechanical properties and heat resistance will deteriorate, which is not preferable. Furthermore, the methacrylic acid component constituting the copolymer has a great effect on improving the flame retardancy and heat resistance of the flame-retardant resin composition of the present invention, and its usage ratio is 1
~15% by weight, preferably 3-10% by weight, more preferably 5-7% by weight. Usage rate is 1% by weight
If it is less than 15% by weight, the effect of improving flame retardancy and heat resistance will be small, and if it exceeds 15% by weight, the haze value of the flame-retardant resin composition will increase, and the water absorption rate will increase, which is desirable. do not have. The above are the essential components of the copolymer constituting the composition of the present invention and their usage ratios. , considering the overall balance of resin properties such as optical properties and processability, α−
When the number of moles of methylstyrene is α, the number of moles of styrene is β, and the number of moles of maleic anhydride is γ, the blending ratio of α-methylstyrene, styrene, and maleic anhydride in the copolymer (α+β)/ γ
It is most desirable that the relationship be such that 1.1 to 1.5. When the blending ratio is less than 1.1, there is a tendency for mechanical properties, water resistance and optical properties to decrease, and when it is greater than 1.5, there is a tendency for heat resistance to decrease. In addition, in the present invention, the copolymer constituting the composition may be acrylic acid, methyl acrylate, (meth)acrylate, or
Ethyl acrylate, butyl (meth)acrylate,
Other copolymerizable monomers such as vinyl acetate or polyfunctional crosslinkable monomers such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate 20 in copolymer body
One or more types may be further blended and copolymerized within the range of % by weight or less. In addition, in the present invention, part or all of methacrylic acid, which is one component of the copolymer, may be replaced with an organic acid, for example, an unsaturated organic acid such as acrylic acid, maleic acid, itaconic acid, or a saturated organic acid, as necessary. Although it is possible to replace them, the effect of improving flame retardancy and heat resistance is more remarkable when methacrylic acid is used as in the present invention. The halogen-containing condensed phosphoric acid ester of the flame retardant used to form the composition of the present invention is preferably a chlorinated polyphosphate, and the phosphorus content in the chlorinated polyphosphate is 5 to 30% by weight, preferably 10% by weight. ~20% by weight and chlorine content of 20 to 40% by weight are desirable because they have a large flame retardant effect. Chlorinated polyphosphates are produced, for example, by Daihachi Kagaku Kogyosho Co., Ltd. CR-505, CR
Examples include -509, CR-511 and CR-513, Vyroll 77 produced by Kashima Kogyo Co., Ltd., and AFR-TH101 produced by Asahi Glass Co., Ltd. Among these, CR-509 is effective when used in the resin composition of the present invention. Although the exact structure of CR-509 is unknown, it is a chlorine-containing condensed phosphoric acid ester having a phosphorus-carbon bond, and its chlorine content is 26.0% and phosphorus content is 14.0%. The amount of the halogen-containing condensed phosphoric acid ester used in the present invention cannot be absolutely determined depending on the degree required for the product, but is usually 3 to 40% by weight, more preferably 10 to 30% by weight in the resin composition. It is. If the amount of the flame retardant is less than 3% by weight, it will not be sufficient in terms of imparting flame retardancy, and if it exceeds 40% by weight, the physical properties of the resin composition will decrease, such as the heat resistance will decrease and the water absorption rate will increase. Undesirable. The resin composition of the present invention can be produced by adding a flame retardant to the monomer mixture or a partial polymer thereof to initiate polymerization. Examples include a method of bulk polymerization or solution polymerization in the presence of a flame retardant, and a method of blending a copolymer made of the above-mentioned monomers with a flame retardant. A preferred example of adding a flame retardant to a monomer mixture or a partial polymerization thereof and carrying out polymerization in the presence of a polymerization initiator is to add 0.01 to the monomer mixture or a partial polymerization thereof. 50-150℃, preferably 65-150℃ with addition of ~1.0% by weight of polymerization initiator
After adding and dissolving a flame retardant and a polymerization initiator into the partially polymerized product obtained by heating at a temperature of 100℃,
It is injected into a cell composed of a template made of glass, stainless steel, or aluminum, etc. and a gasket made of polyvinyl chloride, and polymerized at a temperature of 50 to 90°C, and then at a temperature of 100 to 160°C for 10 to 180 minutes. Cast polymerization is a bulk polymerization method in which post-polymerization is performed. The method for preparing a partial polymer when performing cast polymerization is not particularly limited, and in addition to the above method, for example, a partial polymer of methyl methacrylate may be mixed with the other monomer components and a flame retardant as described above. Examples include a method of dissolving a methyl methacrylate polymer or a copolymer thereof and a flame retardant in a mixture of other monomers with methyl methacrylate. The component composition and the component composition of the monomer mixing portion may be different. As the polymerization initiator used in cast polymerization, known radical polymerization initiators can be used, such as azobisisobutyronitrile, 2-
Azobis-based catalysts such as 2'-azobis-2,4-dimethylvaleronitrile, lauroyl peroxide, benzoyl peroxide, bis(3,5,
Examples include diacyl peroxide catalysts such as 5-trimethylhexanoyl) peroxide, and percarbonate catalysts. On the other hand, as a method for producing a composition by a blending method, there may be mentioned a method of blending a pulverized product or a melt of a copolymer obtained by bulk or solution polymerization with a flame retardant and extruding the mixture. If desired, other known flame retardants can be used in combination with the resin composition of the present invention.
Additionally, additives such as ultraviolet absorbers, mold release agents, heat stabilizers, plasticizers, lubricants, antistatic agents, foaming agents, dispersants, nucleating agents, and coloring agents may be added as necessary. In addition, aluminum hydroxide, magnesium hydroxide,
Inorganic fillers such as glass fibers and glass powder, powdered metals, carbon black, etc. can also be added. Instead of using a conventional methyl methacrylate polymer or a copolymer of methyl methacrylate and methacrylic acid as a base polymer, the flame-retardant acrylic resin composition of the present invention uses a monomer mixture having the above-described specific composition of the present invention. Or, by using a resin composition of a copolymer obtained from a partial polymer thereof and using a halogen-containing condensed phosphoric acid ester as a flame retardant, the flame retardance when using the same amount of flame retardant. It has the effect of significantly improving flame retardancy compared to acrylic resin. Since the acrylic resin composition according to the present invention has excellent flame retardancy and physical properties, it is useful for applications such as building materials, electrical equipment materials, signboards, glazing materials, and lighting materials. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, which are merely illustrative of the present invention and are not intended to limit the present invention in any way. Example 1 760 g of methyl methacrylate, 40 g of α-methylstyrene, 100 g of styrene and 100 g of maleic anhydride
g into a separable fusco equipped with a cooling tube, thermometer, and stirring rod, and heated while stirring until the internal temperature
At 70°C, 1.0 g of 2,2-azobis-(2,4-dimethylvaleronitrile) was added, the internal temperature was maintained at 95°C for 10 minutes, and then cooled to room temperature to obtain a syrup-like partial polymer. For 730 g of this partial polymer, 70 g of methyl methacrylate, CR-509 (chlorinated polyphosphate,
Daihachi Kagaku Kogyo Co., Ltd., trade name) 200g, aerosol OT (dioctyl sulfosuccinate) 1g and 2,2'-azobis-(2,4
After adding and dissolving 640 mg of dimethylvaleronitrile, the composition was poured into a cell formed by two pieces of tempered glass facing each other at a 3 mm interval with a polyvinyl chloride gasket interposed therebetween, and placed in hot water at 65°C for 16 hours. It was immersed for a time to polymerize and harden. Then, it was heat treated in an air heating furnace at 135°C for 2 hours. After cooling, the frame was removed to obtain a resin plate with a thickness of approximately 3 mm. A vertical combustion test was conducted on this resin plate in accordance with UL standard Subject 94. The first 10 for a set of 5 samples.
The combustion duration after flame contact for 1 second and the combustion duration after second flame contact for 10 seconds were measured, and the results are shown in Table 1.

[Table] Comparative Example 1 Except for preparing a syrup-like partial polymer by using only 1000 g of methyl methacrylate monomer instead of the monomer mixture of methyl methacrylate, α-methylstyrene, styrene, and maleic anhydride. A 3 mm resin plate was obtained in exactly the same manner as in Example 1. Next, a combustion test similar to that in Example 1 was conducted, and the results are shown in Table 2.

[Table] Comparing the results in Tables 1 and 2, it was found that the flame-retardant acrylic resin composition of the present invention has the same flame-retardant properties as the conventional flame-retardant acrylic resin composition that uses a copolymer of methyl methacrylate and methacrylic acid as a base polymer. It is clear that the flame retardance is much superior to that of acrylic resin compositions. Example 2 1000g of methyl methacrylate was added to a cooling tube, thermometer,
After putting it into a separable flask equipped with a stirring bar, heat it while stirring to obtain 650 mg of 2,2'-azobis-(2,4-dimethylvaleronitrile) at an internal temperature of 85°C.
was added, the internal temperature was maintained at 100°C for 7 minutes, and then cooled to room temperature to obtain a syrup-like partial polymer. For 558.4 g of this partial polymer, 25.6 g of α-methylstyrene, 73 g of styrene, and 73 g of maleic anhydride.
g, 70 g of methacrylic acid, 200 g of CR-509, 1 g of Aerosolol OT, and 2,2'-azobis-(2,
After adding and dissolving 640 mg of 4-dimethylvaleronitrile, the composition was injected into a cell formed by two sheets of tempered glass facing each other at a 3 mm interval with a polyvinyl chloride gasket interposed therebetween, and heated with 65°C hot water. inside
It was immersed for 16 hours to polymerize and harden. The mixture was then treated in an air heating oven at 135°C for 2 hours. After cooling, the frame was removed to obtain a resin plate with a thickness of 3 mm. A vertical combustion test was conducted on this resin plate in accordance with UL standard Subject 94. The combustion duration after the first and second 10-second flame contact was measured for a set of five samples in the same manner as in Example 1, and both were less than 1 second, indicating that the flame retardance was good. It was hot. Comparative Example 2 Example 2 except that only 730 g of a partial polymer of methyl methacrylate was used without using α-methylstyrene, styrene, or maleic anhydride.
A 3 mm resin plate made of a copolymer of methyl methacrylate and methacrylic acid was obtained in exactly the same manner as above. When this resin plate was subjected to a combustion test similar to Example 2, the combustion duration after the first 10-second flame contact was about 2 seconds, but the combustion duration after the second 10-second flame contact was There was one that lasted more than 30 seconds. Example 3 For 604 g of the syrup-like partial polymer of methyl methacrylate prepared in Example 2, 28 g of α-methylstyrene, 79 g of styrene, 79 g of maleic anhydride,
Methacrylic acid 60g, CR-509 150g, aerosol
After adding and dissolving 1 g of OT and 672 mg of 2,2'-azobis-(2,4-dimethylvaleronitrile),
A resin plate having a thickness of 3 mm was obtained in the same manner as in Example 2. This resin plate has the same UL standards as Example 1.
A vertical combustion test was conducted in accordance with Subject 94.
The combustion duration after the first and second 10 second flame contact was measured for a set of five samples.
The results are shown in Table 3.

[Table] When the optical properties of this plate were measured in accordance with ASTM D1003, the total light transmittance was 92.4% and the haze value was 1.0%, which were good. Also, the heat distortion temperature
When measured in accordance with ASTM D648, it was 96.0, which was good. Comparative Example 3 A resin plate for comparison was obtained in exactly the same manner as in Example 3, except that 790 g of a partial polymer of methyl methacrylate was used without using α-methylstyrene, styrene, or maleic anhydride. Ta. A combustion test similar to that in Example 3 was conducted on this resin plate, and the results are shown in Table 4.

[Table] It is clear from a comparison of Tables 3 and 4 that the flame-retardant acrylic resin composition of the present invention exhibits excellent effects.

Claims (1)

[Claims] 1 From 40 to 88% by weight of methyl methacrylate, 1 to 15% by weight of α-methylstyrene, 5 to 15% by weight of styrene, 5 to 15% by weight of maleic anhydride, and 1 to 15% by weight of methacrylic acid. 1. A flame-retardant acrylic resin composition comprising a copolymer consisting of a halogen-containing condensed phosphoric acid ester and a halogen-containing condensed phosphoric ester, the composition containing 3 to 40% by weight of the halogen-containing condensed phosphoric ester. 2 Methyl methacrylate monomer or its partial polymer 40-88% by weight, α-methylstyrene 1-15% by weight, styrene 5-15% by weight, maleic anhydride 5
Polymerization is initiated by adding halogen-containing condensed phosphoric acid ester to a monomer mixture of ~15% by weight and 1 to 15% by weight of methacrylic acid or a partial polymer thereof so that the halogen-containing condensed phosphoric acid ester is 3 to 40% by weight in the composition. 1. A method for producing a flame-retardant acrylic resin composition, which comprises polymerizing in the presence of an agent.