JPS6239655A - Flame-retardant styrene resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition capable of giving a molded article having excellent impact resistance, heat-resistance, moldability and flame-retardancy,by compounding a rubber-reinforced styrene resin with poly-p-methylstyrene and a flame-retardant. CONSTITUTION:The objective composition is composed of (A) a rubber-reinforced styrene resin, (B) a poly-p-methylstyrene and (C) a flame-retardant. The amount of the component B is 15-80ptw.wt. per 100pts. of the monomer component constituting the styrene resin. The weight-average particle diameter of the rubber component in the component A is 0.6-6mu, preferably 0.8-3mu.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention is a material for manufacturing housings for electrical products such as radios, televisions, and electric refrigerators, and housings for office equipment such as office computers, microcomputers, and word processors. , and for manufacturing various other molded products.
Commonly used flame-retardant styrene with excellent impact resistance and heat resistance "Conventional technology-1 Conventionally, by adding a flame retardant to the styrene-based jHl1ff reinforced with rubber, rubber reinforcement with excellent flame retardance was created. It is known to produce styrene M!H)jW.

However, the flame-retardant rubber-reinforced styrenic resin obtained in this way has the excellent properties that the rubber-reinforced styrenic resin before adding the flame retardant, that is, impact resistance and heat resistance. However, there was a drawback that the addition of flame retardants lowered the performance.

It is also possible to produce flame-retardant resin by adding flame retardants to rubber-reinforced polyparamethylstyrene.
In reality, rubber-reinforced polyparamethylstyrene has excellent heat resistance, but its impact resistance is considerably lower than that of other rubber-reinforced styrenic resins, so it is not practically satisfactory. There were drawbacks.

[Problems to be solved by the invention] The present invention solves problems that could not be solved using known methods.
It is an object of the present invention to provide a styrene-based composition that has four characteristics: 1) impact resistance, and 1) impact resistance.

The gist of the present invention is that rubber-reinforced styrene M7
4 (tuff) In a flame-retardant styrenic resin composition containing polyparamethylstyrene and a flame retardant, when the monomer component constituting the styrene resin is 100 parts by weight, the paramethylstyrene component is 15 to 80 parts by weight. A flame-retardant styrenic resin composition which contains within the range of parts by weight.

The present invention will be explained in detail below.

In the present invention, rubber-reinforced styrenic resin (U) refers to a rubber-reinforced styrenic resin obtained by graft copolymerizing styrenic monomers in the presence of a rubber component.Here, the rubber component includes polybutadiene, Examples include copolymers of butanoene and other copolymerizable monomers containing 50% by weight or more of butadiene, polyisoprene, polychloroprene, and the like.

Monomers to be copolymerized with butanoene include styrene,
Examples include acrylic acid, methacrylic acid, alkyl esters thereof, acrylonitrile, methacrylonitrile, and the like.

The styrenic monomer to be grafted onto the rubber is as follows:
Examples include aromatic alkenyl compounds such as styrene, α-7-tylstyrene, and vinyltoluene, but these are the main components, and 15% by weight or less of para-methylstyrene, acrylonitrile, acrylic acid, methacrylic acid, and alkyl esters thereof are used. May contain.

The amount of rubber component included in the rubber-reinforced styrene resin is
Rubber reinforced styrene resin 100% by weight, 4-2
If the amount of this rubber component is less than 4%, the impact resistance of the rubber-reinforced styrene obtained will not be sufficient, and if it is more than 20%, the viscosity will increase during the manufacturing process. Since a large amount of solvent is required, industrial production is difficult, and it is also economically disadvantageous.

In addition, the rubber-reinforced styrenic resin is styrene M'iI
It is preferable that a rubber component to which these styrenic monomers are grafted is dispersed in a polymer derived from a styrene monomer. The rubber component dispersed in the polymer has a weight average particle size of 0.6~
Preferably it is in the range of 6 microns, preferably 0.8'53 microns.

This is because if the weight average particle size of the dispersed rubber component is outside this range, it may have a significant effect on the impact resistance and appearance of the molded product.

As a method for graft copolymerizing a styrene monomer in the presence of a rubber component, any commonly used method such as bulk polymerization, solution polymerization, bulk suspension method, etc. may be applied.

The polyvaramethylstyrene used in the present invention includes:
A homopolymer of para-methylstyrene, or a copolymer of para-methylstyrene as a main component and a copolymerizable monomer. Examples of the Ti compound to be copolymerized with para-methylstyrene include aromatic alkenyl compounds such as styrene, α-methylstyrene, and vinyltoluene; in addition to these, acrylonitrile, acrylic acid, methacrylic acid, and alkyl esters thereof, etc. It is necessary to select a combination of both monomers so as not to impair compatibility with the Gaagerarene-based resin.

In the flame-retardant styrenic resin composition according to the present invention,
When the monomer component constituting the styrene fruit tree MW is 100 parts by weight, the para-methylstyrene component is selected in the range of 15 to 80 parts by weight, i: necessary.

That is, rubber-reinforced styrenic resin, a component derived from the paramethylstyrene monomer contained in polyparamethylstyrene (I &
min) When setting it as 100 parts by weight, it is necessary to set the para-methylstyrene component to 15 to 80 ml parts. If the amount of paramethylstyrene is less than 15 parts by weight, the resulting styrenic resin composition will not have sufficient flame retardancy, and in order to improve the flame retardancy, it will be necessary to mix in a large amount of flame retardant as usual. . Moreover, since the reactivity of para-methylstyrene is low when para-methylstyrene is 80 parts by weight or more, rubber-reinforced styrene containing a large amount of para-methylstyrene i? , resin, and poly(paramethylstyrene) are both economically disadvantageous and undesirable.

The flame retardant that can be used as an essential component of the present invention may be those commonly used as flame retardants for styrene resins. Specifically, perchloropentanecyclodecane and its modified products, chlorinated paraffin, hexabromobenzene, tetrabromobisphenol A and its modification agent trisdibromopropyl phos7ate, decabromodiphenyl ether, hexabromocyclododecane,
Pentapromuc aa cyclopentadiene, octabrom diphenyl, chlorinated polyethylene, trocresyl phosphate, triethyl phosphate, tris-β-chloroethyl phosphate, trischloroethyl phosphate, triszc+70 propis phosphate, trioxide There are antimony, tin oxide, aluminum hydroxide, magnesium hydroxide, etc., and one type or a combination of two or more of these can be blended. These flame retardants are used in a total amount of 1 (10
It is usually blended in an amount of 25 parts by weight or less, 90 parts by weight. The blend of these flame retardants jt can exhibit sufficient flame retardancy even if it is less than I'h'l, compared to the case of a styrene-based resin that does not contain a para-methylstyrene component.

The hL flammable styrenic resin composition according to the present invention includes various additives of types and amounts that do not adversely affect the properties of the composition.
For example, lubricants, stabilizers, antioxidants, ultraviolet absorbers, colorants, fillers, etc. can be added.

The flame-retardant styrene-based (A) composition according to the present invention is a
It can be used as a material for manufacturing housings for products, equipment, etc., and for manufacturing other molded products.

1. Effects of the Invention j The present invention has the following particularly remarkable effects.
The utility value of the industry is extremely large.

(1) Since the flame-retardant styrenic resin composition according to the present invention contains a specific amount of para-methylstyrene component, it can achieve excellent flame retardancy by simply adding a small amount of an expensive flame retardant compared to the conventional one. It is possible to obtain a molded article that emits a property of RIf.

(2) The flame-retardant styrene-based substitute lubricant M composition according to the present invention contains a para-methylstyrene component, but since it also contains a rubber-reinforced styrenic resin and poly-paramethylstyrene, it has excellent properties. Molded products exhibiting impact resistance and heat resistance can be obtained.

"Examples" Next, the present invention will be explained in more detail with reference examples, working examples, and comparative examples.
You are not limited to the examples below.

Reference Example Production Example of Rubber-Reinforced Polystyrene A〉 85 kg of styrene monomer was placed in a rubber dissolving tank (jacketed pinched paddle blade stirring tank) with an internal volume of 200 I, and pulverized polybutadiene was mixed with Tuball 1220 and Nippon Zeon Co., Ltd. 2 kg of polystyrene fine powder was attached to 13 kg of the same. The temperature was increased from room temperature to 70'C and stirred for 3 hours and 30 minutes to dissolve. At this time, trisnonylphenylphosphite (trisnonylphenylphosphite) is added to the rubber dissolving tank as a stabilizer.
150g was added.

Next, the rubber solution was transferred to a bulk polymerization tank with an internal volume of 2,001 liters (Squid with Noyacket 'A stirring tank), and the temperature was gradually raised while stirring at 55 revolutions per minute. When the temperature inside the polymerization tank reached 70°C, 25 g of No-1-butyl peroxide and 1.31 g of deionized water were added as a polymerization initiator, and the temperature inside the polymerization tank reached 80°C.
When 5°C was reached, 25 g of dodecyl mercaptan as a chain transfer agent and 20 g of butyl peroxybenzoate as a polymerization initiator were added.

The temperature of the polymerization tank was raised from 430'C to 115°C in 2 hours, maintained at this temperature for 1 hour and 30 minutes, and then
An additional 20 g of dodecyl mercaptan was added.

Further, hold at 115℃ for about 30 minutes until the solid content is about 35%.
67 g of a copolymer of acrylic acid and 2-ethylhexyl acrylate and 51 g of polyvinyl alcohol were added as suspending agents.
8g of sodium sulfate and 100kHz of ionized water in which 154g of sodium sulfate and 250g of magnesium sulfate were dissolved.
Suspension polymerization with an internal volume of 3501 heated to 120°C! (7T Udler blade agitation wq with a noyacket), the above reaction mixture was transferred to this suspension polymerization tank, and 130 g of butyl peroxybenzoate was added thereto. After stirring the suspension and maintaining the internal temperature at 120°C for 1 hour and 30 minutes,
It takes 30 minutes to raise the internal temperature to 140°C.
The polymerization reaction was completed by holding for 1 hour.

The product was dehydrated, washed with water, and then dried by heating to obtain rubber-reinforced polystyrene A.

Production example of rubber-reinforced polystyrene B> Add 8 parts by weight of pulverized polybutanoene (Diene NF35AS, manufactured by Asahi Kasei Industries, Ltd.) to 92 parts by weight of styrene, and heat at 40'C while stirring. It took 8 hours to dissolve.

The styrene solution in which the above rubber was dissolved was continuously supplied at a rate of 9 times per hour to a first reactor having an internal capacity of 40 I and equipped with an ink type stirring blade so that the filling rate was 50%. The internal temperature of the first reactor during this period was maintained at 115°C. In addition, in the styrene solution containing the rubber, immediately after feeding into the first reaction 2:
The solution was added continuously to give a concentration of 280 ppHl to the whole body. In this first reactor, the conversion rate to η11100 polymer was set at 25%, and the polymer was taken out and transferred to the next second reactor.

The second reactor is a pressurized sealed type with multiple compartments divided by multiple circular disks, and is equipped with a condenser in the second part of the reactor for the purpose of condensing the evaporated styrene monomer. There is.

The reaction liquid from the fjS1 reactor is sent to the first converter in the second reactor, and the reaction is continuously carried out while adjusting the temperature and pressure so that the temperature in the central compartment of the second reactor is 145°C. I did it. The filling rate of the reactants in the second reactor was maintained at about 40%, and the polymerization reaction was continued while stirring with a horizontal shaft. In this second reactor, the reaction mixture weighs 100 kg! 0.1 part by weight of octadecyl:'(-(3',5'-butyl-4-hydroxyphenyl)propionate based on part Jc, and 1.5f
Added fiu portion of mineral oil. In the second reactor,
Solid content (sum of rubber component and polymer obtained by polymerizing monomers)
was about 72% by weight.

The reaction mixture taken out from the second reactor was 180°C.I.
: Transferred to a controlled pipe reactor, the reaction mixture with increased solids content to about 78% by weight was heated to about 240°C with a heat exchanger and heated to about 1% by weight.
A thin strand was dropped into an unreacted monomer recovery degassing tank maintained at a vacuum of 0 to 15 Torr, and deposited in a molten state at the bottom of the degassing tank.

The amount of unreacted monomer in this deposit was 11,000 pp or less. The recovered unreacted monomer was returned and reused for dissolving rubber in the second reactor.

The melt deposited at the bottom of the degassing tank was extruded as a plurality of strands by a screw installed at the bottom of the degassing tank, and the strands were cooled and cut with a cutter to form berets. The obtained polymer is called rubber-reinforced polystyrene B.

Made of rubber-reinforced polystyrene C! ! Example: Using the same equipment as used in the production example of rubber-reinforced polystyrene B, the raw materials in the same example were changed to paramethylstyrene for styrene, tzene NF35AS for polybutadiene, and diene NF35AS for polybutadiene.
(manufactured by Asahi Kasei Industries, Ltd.) were charged into the first reactor at the same ratio as in the same example, and the polymerization reaction was carried out in the first reactor. The reaction conditions in this reactor were the same as fjS
The procedure was the same as in the 1 reactor.

The reaction mixture from reactor No. 11 was subsequently sent to a second reactor for the next reaction. The reaction conditions in this reactor, the subsequent polymerization conditions, and the fabrication procedure were the same as in the previous example, except that the temperature in the central compartment was 135°C. .

The polymer obtained in this example is called rubber-reinforced polystyrene C.

Example of manufacturing polystyrene: 9 kg of methylstyrene per hour at a temperature of 139°C and a polymerization rate of 4.
It was fed to an ff51 reactor (jacketed helical ribbon blade stirring tank with a content of 8 yen 401) maintained at 3%. The reaction solution was taken out from the first reactor at the same speed by a gear pump, and passed through jacketed piping to the second reactor (inner volume 241, jacketed paddle blade stirrer 4'I) maintained at a temperature of 155°C and a polymerization rate of 72%. !Iso). The reaction liquid taken out from the second reactor by the gear pump at the same speed passes through a back pressure valve installed in the piping with a jacket, and is heated in a heat exchanger in which a heat medium of about 250°C is traced.
The unreacted styrene was dropped into a degassing tank with a vacuum of about 10 Torr to separate unreacted styrene. A plurality of strands were extruded using a screw installed at the bottom of the degassing tank, and the strands were cooled and cut to obtain polystyrene in the form of pellets.

Example of manufacturing polyparamethylstyrene Using the same equipment used in the example of manufacturing polystyrene,
The raw material styrene in the same example was replaced with para-methylstyrene, and the same proportions as in the same example were charged into the first reactor and a reaction was carried out. The reaction conditions in this reactor are a temperature of 137°C.
The hoga that was replaced with was the same as that in the first reactor of the same example.

The reaction mixture from the first reactor was subsequently sent to a second reactor for the next reaction. The reaction temperature in this reactor was 145°C, but the reaction conditions of this reactor, subsequent conditions, and operating conditions were the same as in the previous example.

Examples and Comparative Examples The rubber-reinforced polystyrene, polyparamethylstyrene, and polystyrene obtained in the above reference examples were weighed in the proportions shown in Table 1 and kneaded using an extruder.

Table 1 shows the results of evaluating the analytical properties of the bellet after crosstalk using the following method.

Gel content: This is the precipitate obtained after decomposing beret with methyl ethyl ketone and centrifuging it, and it is expressed as a weight % based on the sample beret.

Molecule '4'j: : Measured by GPC method.

MW=means weight average molecular weight.

M11=means number average molecular weight.

For 100 parts by weight of the above Berent, 100% of the flame retardant is composed of 14,7 parts of tecapromodinyl ether and 3.7 parts of antimony dioxide, and this star is 1'+! ;'II reduction was taken as 90%, and the compositions were blended as shown in Table 1, and test pieces were made from the resulting compositions by injection molding.

The physical properties of one of these test pieces were evaluated according to the following method. The results are shown in Table 1.

Izont impact strength: Based on JIS K-7110.

Vicant needle temperature: Based on JIS K-7206.

MFI: Compliant with JIS K-7210.

Measured at a load of 5 kg and a temperature of 200°C.

Flame retardancy: UL-94 judgment Table 1 From Table 1, the following becomes clear.

(1) The composition according to the present invention exhibits all the necessary conditions specified in the claims, so it not only exhibits impact resistance and heat resistance. Excellent formability,
Moth [Exhibits flammability.

(2) In light of this, in the case of Comparative Example 3 in which rose methylstyrene was grafted to the rubber component, the impact resistance 7 strength was low and there was a problem in practical use. Furthermore, 1↑J to paramethylstyrene
If the flame retardant is not contained but in a small amount, the excellent flame retardant effect will not be exhibited unless the amount of flame retardant added is increased (see Comparative Examples 1, 2, 4, and 5.6).

Claims (1)

[Claims] In a flame-retardant styrenic resin composition containing a rubber-reinforced styrenic resin, polyparamethylstyrene, and a flame retardant,
A flame-retardant styrenic resin composition, characterized in that it contains a para-methylstyrene component in a range of 15 to 80 parts by weight when the monomer component constituting the styrene resin is 100 parts by weight.