JPH0153893B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a flame-retardant acrylic resin molded product having a high degree of flame retardancy and excellent physical properties. More specifically, the present invention involves continuous casting of a polymerization raw material consisting of a resin material consisting of methyl methacrylate, α-methylstyrene, styrene, maleic anhydride, and methacrylic acid, a halogen-containing flame retardant, and a polymerization initiator. The present invention relates to a method for producing a flame-retardant acrylic resin molded product having excellent physical properties. 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 flammable. It is already known that flame retardancy can be imparted to acrylic resins by adding certain organic phosphate esters, but these organic phosphate esters generally have a plasticizing effect, and the resulting acrylic resin moldings are heat-resistant. In addition to significantly lowering the deformation temperature,
It also had drawbacks such as a significant decrease in 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 may become deformed due to water absorption, or craze may occur, resulting in product complaints. It was often the cause of 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. It is. 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 the base polymer. Instead of the resin, a resin material consisting of methyl methacrylate, α-methylstyrene, styrene, maleic anhydride, and methacrylic acid having a specific composition and a halogen-containing flame retardant are continuously added in the presence of a polymerization initiator. The present invention was achieved by discovering that the molded product obtained by polymerization can have superior flame retardancy compared to conventional flame-retardant acrylic resins, and that the production method is economically advantageous. That is, the gist of the present invention is to provide two endless belts that run opposite each other with a certain gap between them, and a gasket that runs to follow the belts while being sandwiched between the two belts. From the upstream end of the molding space formed by
80% by weight of α-methylstyrene, 1-15% by weight of styrene, 5-15% by weight of maleic anhydride, and 1-15% by weight of methacrylic acid, a halogen-containing flame retardant, and polymerization. A method for producing a flame-retardant acrylic resin molded product, which comprises supplying a polymerization raw material consisting of an initiator, continuously polymerizing it inside the molding space, and taking out a plate-shaped polymer from the downstream end. It is in. The methacrylic acid ester component constituting the molded product of the present invention 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 resin material. 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. In addition, the α-methylstyrene component constituting the molded product is one of the components that improves the heat resistance of the molded product obtained.
and in the range of 1 to 15% by weight in the resin material,
It is preferably used in an amount of 3 to 10% by weight. 1
If it is less than 15% by weight, the heat resistance will not be sufficient, and if it exceeds 15% by weight, the mechanical properties will deteriorate and at the same time productivity will decrease. In addition, the styrene component that makes up the molded product is not a component that directly improves the heat resistance and flame retardance of the molded product, but it has a high copolymerization reactivity with α-methylstyrene and maleic anhydride, which are heat resistance improving components. In addition to indirectly improving heat resistance by increasing the It also has very favorable effects. In particular, completely unexpected effects were observed in terms of improvements in mechanical properties and coloration. The usage ratio of styrene is 5 in the resin material.
-15% by weight is required; if it is less than 5% by weight, productivity is poor, and if it exceeds 15% by weight, there is a tendency for heat resistance and optical properties to deteriorate. In addition, the maleic anhydride component that makes up the molded product is α
- It has the effect of increasing the copolymerization reactivity of methylstyrene and its interaction with styrene to improve the heat resistance of molded products, and its usage ratio is 5% of the resin material.
A range of ~15% by weight is required, preferably 10~
It is 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 be degraded. Furthermore, the methacrylic acid component that makes up the molded product has a great effect on improving flame retardancy and heat resistance.
The proportion used is 1 to 15% by weight of the resin material, preferably 3 to 10% by weight, more preferably 5 to 7% by weight. If the usage rate is less than 1% 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 molded product will increase, and the water absorption rate will increase, which will have negative effects on physical properties. . The above are the essential components constituting the molded product of the present invention and their usage ratios. Considering the overall balance of resin properties such as It is most desirable that the mixing ratio (α+β)/γ of maleic anhydride is in the range of 1.1 to 1.5. The blending ratio is
When it is smaller than 1.1, mechanical properties, water resistance and optical properties tend to decrease, and when it is larger than 1.5, heat resistance tends to decrease. In addition, in the present invention, depending on the purpose of use, acrylic acid, methyl acrylate, ethyl (meth)acrylate, (meth)acrylate,
Other copolymerizable monomers such as butyl acrylate, vinyl acetate or polyfunctionals such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate Copolymerization may be carried out by further blending one or more crosslinkable monomers within the range of 20% by weight or less of the resin material. Furthermore, in the present invention, part or all of methacrylic acid, which is one component of the copolymerization, may be replaced with other organic acids, such as unsaturated organic acids such as acrylic acid, maleic acid, itaconic acid, and saturated organic acids, 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 flame retardant used to construct the molded article of the present invention is a halogen-containing flame retardant such as a halogen-containing condensed phosphoric acid ester or a halogenated polyphosphonate. As the halogen-containing condensed phosphoric acid ester, chlorinated polyphosphate is desirable, and among the chlorinated polyphosphates, phosphorus content is 5 to 30% by weight, preferably 10 to 20% by weight, and chlorine content is 20 to 40% by weight.
% by weight is preferable because it has a large flame retardant effect. Examples of chlorinated polyphosphates include CR-505 and CR- produced by Daihachi Chemical Industry Co., Ltd.
509, CR-511 and CR-513, Pyrrole 77 produced by Kashima Kogyo Co., Ltd., and AFR-TH101 produced by Asahi Glass Co., Ltd., etc. Among these, CR-509 is effective when used in the present invention. Although the exact structure of CR-509 is unknown, it is a chlorine-containing condensed phosphoric acid ester with a phosphorus-carbon bond, and its chlorine content is
26.0%, phosphorus content is 14.0%. Further, as the halogenated polyphosphonate used in the present invention, chlorinated polyphosphonates are preferable, and among them, a compound of the following formula called Phosgard C-22-R produced by Monsanto Company in the United States is particularly effective. . The amount of the halogen-containing flame retardant used in the present invention cannot be determined unconditionally depending on the degree required for the product, but it is usually 3 to 40% by weight in the resin molding.
More preferably, it is 10 to 30% by weight. 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, there will be a tendency for physical properties to deteriorate significantly, such as a decrease in heat resistance and an increase in water absorption. The production method of the present invention comprises a resin material comprising the above-mentioned methyl methacrylate monomer or a partial polymer thereof, α-methylstyrene, styrene, maleic anhydride and methacrylic acid, the above-mentioned flame retardant, and a required amount of polymerization initiation. After the polymerization raw material is prepared by adding the agent, the polymerization raw material is sandwiched between the opposing surfaces of two endless belts that run opposite each other with a certain gap between them, and the two belts run. This is a method in which the polymer is supplied from the upstream end into a molding space formed by a gasket that follows the gasket, is continuously polymerized inside the molding space, and is taken out in the form of a plate from the downstream end. The method for preparing the polymerization raw material in the method of the present invention is not particularly limited, and for example, a flame retardant is added to the monomer mixture described above, or a flame retardant is dissolved in the monomer mixture described above. After that, 0.01~1
Adding a radical polymerization initiator in an amount of 50~
Either by heating at 150°C, preferably 65 to 100°C for a certain period of time, or by mixing and dissolving the above-mentioned other monomer components and a flame retardant in the methyl methacrylate partial polymer, or by heating the methyl methacrylate partial polymer or the methyl methacrylate polymer. A liquid or syrupy resin material is prepared by dissolving the copolymer and flame retardant in a mixture of methyl methacrylate and other monomers, and then a polymerization initiator is added to the resin material. Examples include a method of adding 0.01 to 1.0% by weight, preferably 0.02 to 0.5% by weight. In addition, in the method of the present invention, the component composition of the polymer portion and the component composition of the monomer mixed portion in the resin material may be different. The viscosity of the polymerization raw material is not particularly limited, but it is preferably about 300 to 10,000 centipoise (cp) (20° C.) since it is injected onto the belt surface from an injection device. If the viscosity of the polymerization feedstock is lower than this, there is a risk that the polymerization feedstock may leak through the gasket or the injection end of the belt, and if the viscosity of the polymerization feedstock is too high, it may be difficult to inject onto the belt or may cause problems in the piping. There are difficulties in handling such as the risk of polymerization. The polymerization raw material containing the flame retardant prepared as described above is then injected from an injection device located at one end of the endless belt into a molding space surrounded by both upper and lower belts and a gasket. The polymerization raw material injected into the belt advances as the endless belt runs, and is heated to 50 to 95°C in the first polymerization zone to polymerize and harden, and in the second polymerization zone to 100 to 95℃.
Heat treated at 160℃ to reduce residual monomers,
The endless belt is then cooled, separated from the endless belt from the other end, and taken out as a plate-shaped product of about 0.5 to 30 mm. The polymerization time is 10 to 90 minutes in total for the first polymerization zone and the second polymerization zone. In addition, the running speed of the endless belt is 0.5 ~
4.0 m/min is preferred. In the method of the present invention, it is necessary for the polymerization raw materials injected into the opposing endless belts to enter the second polymerization zone in a state in which most of them are polymerized and cured in the first polymerization zone. Choice is very important. In the method of the present invention, suitable known radical polymerization initiators can be used, examples of which include azobis-based radical polymerization initiators such as azobisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile. Catalysts, diacyl peroxide catalysts such as lauroyl peroxide, benzoyl peroxide, bis(3,5,5-trimethylhexanoyl) peroxide, and percarbons such as bis(4-t-butylcyclohexyl) peroxydicarbonate. Examples include nerat-based catalysts and the like. Particularly suitable polymerization initiators in the present invention have a decomposition temperature of 30 to 90°C, preferably 40 to 90°C, with a half-life of 10 hours.
It is at 80℃. Among them, 2,2'-azobis-2,4-dimethylvaleronitrile, azobisisobutyronitrile, bis(3,5,5-trimethylhexanoyl) peroxide, bis(4-t
-butylcyclohexyl) peroxydicarbonate is particularly preferred. In the method of the present invention, other known flame retardants can also be used in combination, if desired. Additionally, additives such as ultraviolet absorbers, mold release agents, heat stabilizers, plasticizers, lubricants, antistatic agents, foaming agents, dispersants, and colorants may be added as necessary. Furthermore, inorganic fillers such as aluminum hydroxide, magnesium hydroxide, glass fiber and glass powder, powdered metals, carbon black, etc. can also be added. Next, a continuous plate-making apparatus used in the method of manufacturing a sheet-like product which is a flame-retardant acrylic resin molded product of the present invention will be explained based on the drawings. FIG. 1 shows an example for implementing the present invention. However, the continuous plate making apparatus used in the present invention is not limited to the apparatus shown in the drawings. In FIG. 1, reference numerals 1 and 1' indicate endless belts, which are generally made of metal such as steel or stainless steel. These metal belts are carefully polished and, in some cases, plated to obtain sheets with excellent surface appearance. The thickness of the metal belt is 0.1~
It is preferably 3 mm, particularly 0.5 to 2 mm. A predetermined tension is applied to the belt by main pulleys 2, 3 and 2', 3'. In the example shown in Fig. 1, hydraulic cylinders are provided on the main pulleys 2 and 2',
By changing the oil pressure, the belt tension can be changed. It is also known to adjust belt tension using springs or other mechanical methods. The belt tension is preferably as high as possible in order to improve the belt configuration and sheet thickness accuracy, but it is generally operated at 3 to 15 kg/mm ² . The belt is made to run by driving the main pulley 3'. The belt is main pulley 2 and 3,
By adjusting the angles of 2' and 3', the meandering can be adjusted. The meandering adjustment of the belt can also be adjusted by changing the angle of the rolls 4, 4' in contact with the back side of the belt or of the rolls provided on the return side of the belt (not shown). 5 shows the supply process of polymerization raw materials,
Monomers or partially polymerized materials (silp) mixed with catalysts and other auxiliaries are generally fed at a constant flow rate using a metering pump. Reference numeral 6 denotes an injection device for supplying this liquid polymerization raw material to the space between the opposing belts. Gaskets 7 and 7' run following the running of the belt while being sandwiched between the opposing belts to prevent the polymerization raw material from leaking to the outside of the belt. The gasket used may be made of soft polyvinyl chloride, polyethylene, ethylene-vinyl acetate copolymer, polyurethane, or other materials. 4 and 4' indicate a group of rolls supporting the opposing belts from the back side. The rolls must be arranged in front of and in the polymerization zone to such an extent that the polymerization raw material does not leak out from the space formed by the opposing belts and gaskets. The belt flexes between adjacent rolls due to the liquid pressure of the polymerization raw material, the repulsive force of the gasket, etc., but as the amount of flexure increases, the sheet thickness accuracy deteriorates, and the gap between the belt and the gasket increases. If this occurs, the polymerization raw material will leak. In some cases, outside air may enter through the gaps and form bubbles in the sheet. A way to solve these problems is to keep the deflection of the belt to a minimum, but as a means to do so, it is desirable to narrow the roll arrangement interval and increase the belt tension. For this purpose, the roll arrangement interval, that is, the distance between the centers of adjacent rolls, must be approximately 20 to 100.
Preferably in cm. The rolls are set so that even when the polymerization raw material polymerizes and shrinks, it moves with the polymerization raw material and does not move away from the back surface of the belt. Reference numerals 8 and 8' indicate spray devices for heating the belt provided in the polymerization zone by applying leakage water to the belt. Any temperature below 100°C can be used as the hot water temperature, but in order to avoid increasing the size of the continuous polymerization equipment and increase productivity, it is preferable to polymerize as quickly as possible, and generally around 50 to 95°C. temperature is used. Reference numerals 9 and 9' indicate far-infrared heaters installed in the second polymerization zone that heat the sheet to 100°C or higher, usually 100 to 160°C, in order to remove residual monomers. A far-infrared heater is an effective heating means for raising the temperature of the sheet. In order to effectively utilize the amount of heat generated by the heater, the belt and the heater are generally covered with a heat insulating duct. The heated sheet passes through the heat insulation duct so that it is maintained at the required temperature for the required time. Multiple far-infrared heaters can be installed as appropriate or air can be blown into the heat insulation duct to obtain an appropriate temperature profile. It is also possible to provide other methods, for example a hot air stove. Reference numerals 10 and 11 indicate cooling or heat retention zones for cooling the sheet that has passed through the second polymerization zone under appropriate conditions. 12 indicates a sheet manufactured through the above process. The method of the present invention makes it possible to produce flame-retardant acrylic resin molded articles with excellent flame retardancy continuously and with high productivity, and furthermore, it is possible to produce flame-retardant acrylic resin molded articles with excellent flame retardant properties, and furthermore, it is possible to produce flame-retardant acrylic resin molded articles with excellent flame retardancy, and furthermore, it is possible to produce flame-retardant acrylic resin molded articles with excellent flame retardance, and furthermore, it is possible to produce flame-retardant acrylic resin molded articles with excellent flame retardance. It is possible to produce long sheets and wide sheets, which is extremely advantageous industrially. The flame-retardant acrylic resin molded article obtained by the method of the present invention uses methyl methacrylate homopolymer or a copolymer of methyl methacrylate and methacrylic acid as the base polymer used in conventional flame-retardant acrylic resins. By using the resin raw material having the specific composition of the present invention and using a halogen-containing flame retardant therein, the flame retardance is higher than that of conventional flame retardant acrylic resin when the same amount of flame retardant is used. It shows the effect of significantly improving performance. Acrylic resin molded products produced by the method of the present invention have excellent flame retardancy and physical properties, and are therefore useful for applications such as building materials, electrical equipment materials, signboards, glazing materials, and lighting materials. be. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but these are merely illustrative of the present invention and are not intended to limit the present invention in any way. In the examples, parts are parts by weight, and % is % by weight. In addition, physical property evaluation in Examples was measured based on the following method. Combustion test Using the vertical method in accordance with the US UL standard Subject 94, for a set of 5 samples (1) Combustion duration (seconds) after the first 10 seconds of flame contact
and (2) the combustion duration (seconds) after the second 10 second flame contact was measured. Example 1 76.5% methyl methacrylate, 3.5% α-methylstyrene, 10% styrene, and 10% maleic anhydride were placed in a 3000 cylindrical vertical reactor equipped with a heating jacket, a cooling jacket, a condenser, and a vertical stirrer. A monomer mixture of 1000 g was charged and heated. When the temperature of the monomer mixture rose to 80°C, 2,2'-azobis-2,4-dimethylvaleronitrile was added to the monomer mixture as a polymerization initiator.
0.25% was added and stirred. The monomer mixture starts the polymerization reaction, reaches saturation temperature due to polymerization heat, begins to reflux from the condenser, and after 15 minutes have passed from the time when the polymerization initiator is added, it is rapidly cooled and heated to 20°C. viscosity is 2610cp, polymerization conversion rate is 31%
A syrup-like partial polymer was obtained. Sillage partial polymer prepared as above
73 parts, 7 parts of methacrylic acid, CR-509 (chlorinated polyphosphate, manufactured by Daihachi Chemical Industry Co., Ltd.) 20
1,000 ppm of Aerosolol OT (dioctyl sulfosuccinate) and Trigonox 36 (bis(3,5,6-trimethylhexanoyl) peroxide, Kayaku Nouri Co., Ltd.) as an additional polymerization initiator.
Co., Ltd.) was added at a ratio of 0.4% to the resin component and stirred to dissolve. The resulting polymerization raw material was then degassed under reduced pressure and injected into a continuous polymerization apparatus equipped with a mirror-finished stainless steel belt 2 mm thick and 1200 mm wide and set to a belt clearance of 3 mm as shown in Figure 1. 80℃
for 30 minutes, then heated and polymerized at 136℃ for 3 minutes,
A resin plate with a thickness of 3 mm was obtained. A combustion test was conducted on this resin plate. The results are shown in Table 1. The resulting resin plate had good transparency and a haze value (measured according to ASTM D1003) of 1.5%.

[Table] Comparative Example 1 Only methyl methacrylate monomer was charged into the same cylindrical vertical reaction tank as in Example 1 and heated. When the monomer was heated to 80℃, 2,
0.065% of 2'-azobis-2,4-dimethylvaleronitrile based on the monomer was added and stirred. The monomer starts the polymerization reaction, reaches a saturation temperature due to the heat of polymerization, begins to reflux from the condenser, and after 8 minutes have passed from the time when the polymerization initiator is added, it is rapidly cooled and the viscosity at 20°C is A syrup-like partial polymer was obtained with a yield of 1800 cp and a polymerization conversion rate of 22%. Sillage partial polymer prepared as above
73 parts, 7 parts of methacrylic acid, CR-509 20
1,000 ppm of aerosol OT and 2,2'-azobis-2,4-dimethylvaleronitrile as an additional polymerization initiator were added at a ratio of 0.083% to the resin components and dissolved by stirring. Next, this obtained polymerization raw material was degassed under reduced pressure, and then poured into a continuous polymerization apparatus with the same vector clearance as in Example 1 set to 3 mm, and heated at 74°C for 33°C.
minutes, then heat polymerized at 136℃ for 3.5 minutes and plate thickness 3
A resin plate of mm was obtained. A combustion test similar to that in Example 1 was conducted on this resin plate, and the results are shown in Table 2.

[Table] By comparing Tables 1 and 2, the flame-retardant acrylic resin board of the present invention is compared to the conventional flame-retardant acrylic resin board whose base polymer is a copolymer of methyl methacrylate and methacrylic acid. It can be seen that its flame retardancy is very excellent. Example 2 In the same manner as Comparative Example 1, the viscosity at 20°C was
A syrup-like partial polymer of 3570 cp of methyl methacrylate was prepared, and the syrup-like partial polymer was 502.6 cp.
per part, 25.6 parts of α-methylstyrene, 73 parts of styrene, 73 parts of maleic anhydride, 70 parts of methacrylic acid.
1 part, 200 parts of CR-509, 1 part of Aerosolol OT, 363.2 parts of Trigonox, and Acrypet VH (manufactured by Mitsubishi Rayon Co., Ltd., polymethyl methacrylate powder)
55.8 parts were added and dissolved. Next, the resulting polymerization raw material was degassed under reduced pressure, poured into the continuous polymerization apparatus of Example 1 with a belt clearance of 3 mm, and heated at 82°C for 33 minutes and then at 136°C for 3.5 minutes for polymerization. A 3 mm resin plate was obtained. The transparency of this plate was good. A combustion test was conducted on this resin plate, and the first and second combustion durations were measured.
Both times were 2 seconds or less, and the flame retardancy was good. Comparative Example 2 To 730 parts of the syrup-like partial polymer of methyl methacrylate of Example 2 with a viscosity of 3570 cp and adjusted to a viscosity of 1100 cp by adding methyl methacrylate monomer, 70 parts of methacrylic acid and CR were added. −509
200 parts of aerosolol OT and 0.664 parts of 2,2'-azobis-2,4-dimethylvaleronitrile were added and stirred to dissolve. The resulting polymerization raw material was then degassed under reduced pressure, poured into the continuous polymerization apparatus of Example 1 with a belt clearance of 3 mm, and heated at 74°C for 33 minutes and then at 136°C for 3.5 minutes to form a plate with a thickness of 3 mm. A resin plate was obtained. A combustion test similar to that in Example 2 was conducted on this resin plate, and the results are shown in Table 3.

[Table] By comparing Example 2 and Comparative Example 2 (Table 3), it was found that the flame-retardant acrylic resin board of the present invention is different from the conventional flame-retardant resin board whose base polymer is a copolymer of methyl methacrylate and methacrylic acid. It is clear that the flame retardance is much superior to that of acrylic resin plates. Example 3 To 604 parts of the syrup-like partial polymer of methyl methacrylate prepared in Example 2, 28 parts of α-methylstyrene, 79 parts of styrene, and 79 parts of maleic anhydride were added.
60 parts of methacrylic acid, 150 parts of CR-509, 1 part of Aerosolol OT and 2,2'-azobis-(2,4
After adding and dissolving 3.4 parts of dimethylvaleronitrile), a resin plate with a thickness of 3 mm was obtained in the same manner as in Example 2. When we conducted a combustion test on this resin board, the maximum combustion duration for the first time was 2.3 seconds, and the maximum combustion duration for the second time was 2.3 seconds.
The maximum combustion duration for the second time was 4.8 seconds. Example 4 A monomer mixture 1000 consisting of 76.5% methyl methacrylate, 3.5% α-methylstyrene, 10% styrene and 10% maleic anhydride was charged into the cylindrical vertical reaction tank of Example 1 and heated. When the monomer mixture was heated to 80°C, 2,2'-
Azobis-2,4-dimethylvaleronitrile was added in an amount of 0.25% based on the monomer mixture and stirred.
The monomer mixture starts the polymerization reaction, reaches a saturation temperature due to the polymerization heat, and begins to reflux from the condenser. After 15 minutes have passed from the time when the polymerization initiator is added, the monomer mixture is rapidly cooled and the viscosity at 20℃ is reduced. A syrup-like partial polymer of 2490 cp and a polymerization conversion of 30% was obtained. Sillage partial polymer prepared as above
73 parts, 7 parts of methacrylic acid, Phosgard C
-22-R (chlorinated polyphosphonate, Monsanto
Co., Ltd.) 20 parts, 1000 ppm of dioctyl sulfosuccinate as a stripping agent, and Trigonox 36 (bis(3,5,5-trimethylhexanoyl) peroxide, manufactured by Kayaku Nouri Co., Ltd.) as an additional initiator.
was added at a ratio of 0.4% to the resin component and stirred to dissolve. Next, the resulting polymerization raw material was degassed under reduced pressure, poured into the continuous polymerization apparatus of Example 1 with a belt clearance set to 3 mm, and heated and polymerized at 80°C for 30 minutes and then at 136°C for 3 minutes to form a plate with a thickness of 3mm. A flame-retardant acrylic resin plate was obtained. A combustion test was conducted on this resin plate. The results are shown in Table 4.

[Table] For comparison, the same procedure as in Comparative Example 1 was carried out using only methyl methacrylate monomer instead of the monomer mixture of methyl methacrylate, α-methylstyrene, styrene, and maleic anhydride. The viscosity at 20℃ is 1750 cp, and the polymerization conversion rate is 21.
% syrup-like partial polymer was prepared, and using this syrup-like partial polymer, a sheet containing Phosgard C-22-R having a thickness of 3 mm was prepared in exactly the same manner as in the case of the syrup using the above monomer mixture. A resin plate was obtained. A combustion test was conducted on this plate, and the results are shown in Table 5.

【table】 [Brief explanation of drawings]

FIG. 1 is a side view of the entire apparatus showing an example for carrying out the present invention, in which 1 and 1' are endless belts, 2, 2', 3, and 3' are main pulleys, 5 is an injection device, 7, 7' represents a gasket, and 12 represents a sheet.

Claims (1)

[Claims] 1. It is formed by the opposing surfaces of two endless belts that run opposite each other with a certain gap, and a gasket that runs following the belts while being sandwiched between the two belts. From the upstream end of the molding space, 40 to 80% by weight of methyl methacrylate monomer or a partial polymer thereof, 1 to 15% by weight of α-methylstyrene, 5 to 15% by weight of styrene, and 5% by weight of maleic anhydride.
A polymerization raw material consisting of a resin material consisting of ~15% by weight and 1~15% by weight of methacrylic acid, a halogen-containing flame retardant, and a polymerization initiator is supplied, and this is continuously polymerized inside the molding space, and then the downstream A method for producing a flame-retardant acrylic resin molded product, characterized by taking out a plate-shaped polymer from the end. 2. The flame-retardant acrylic resin molded product according to claim 1, wherein the halogen-containing flame retardant is at least one selected from halogen-containing condensed phosphoric acid esters and halogenated polyphosphonates. manufacturing method. 3. The method for producing a flame-retardant acrylic resin molded article according to claim 1, wherein the polymerization initiator is 2,2'-azobis-2,4-dimethylvaleronitrile. 4. The method for producing a flame-retardant acrylic resin molded article according to claim 1, wherein the polymerization initiator is bis(3,5,5-trimethylhexanoyl) peroxide. 5. The method for producing a flame-retardant acrylic resin molded article according to claim 1, wherein the polymerization initiator is bis(4-t-butylcyclohexyl) peroxydicarbonate. 6. The method for producing a flame-retardant acrylic resin molded article according to claim 1, wherein the polymerization raw material has a viscosity of 300 to 10,000 centivoise (20°C).