KR20000007776A - Preparation method of thermoplastic fire retardant resin composition - Google Patents

Abstract

PURPOSE: A process for manufacturing thermoplastic resin comprising styrene containing copolymer(SAN), phenol resin, polyphenylenether resin, and aromatic ester phosphate is provided which has heat retardancy and heat resistance. CONSTITUTION: The process comprises a)mixing 40-90 weight% of polyphenylenether(PPE) resin having a hindered phenol structure, 10-40 weight% of styrene containing copolymer(SAN) having 5-20 weight% of acrylonitrile and 5-20 weight% of aromatic ester phosphate and extruding at 250-310°C without vacuum, b)mixing extruded master batch having a free transition temperature(Tg) of 90-150°C with styrene containing copolymer(SAN) having 20-40 weight% of acrylonitrile, styrene containing graft copolymer(g-ABS), aromatic ester phosphate, and phenol, and extruding at 200-250°C under vacuum.

Description

Method for producing a thermoplastic flame retardant resin composition

Field of invention

The present invention relates to a method for producing a thermoplastic flame retardant resin composition. More specifically, the present invention relates to a thermoplastic flame retardant resin composition having excellent self-extinguishing properties by containing a phenolic resin, a polyphenylene ether (PPE) resin having a hindered phenol structure, and an aromatic phosphate ester based on a rubber-modified styrene-based resin. It relates to a manufacturing method.

Background of the Invention

Rubber-modified styrene resins have been widely applied to various applications such as electrical appliances and office equipment because of their good processability, particularly excellent impact strength and good appearance. However, when rubber-modified styrene resins are applied to heat dissipating products such as personal computers or fax machines, they are generally flame retardant because of the disadvantage of being combustible. Known flame retardant methods are most commonly applied to the rubber modified styrene resin by applying a halogen compound and antimony compound in combination to impart flame retardant properties. As the halogen-based compound, polybromodiphenyl ether, tetrabromobisphenol A, a brominated substituted epoxy compound, chlorinated polyethylene and the like are mainly used. Antimony-based compounds are mainly composed of antimony trioxide and antimony pentoxide. The flame retardant method achieved by applying halogen and antimony in combination has the advantages of easy flame retardancy and little property deterioration, but it can damage mold due to hydrogen halide gas generated during processing. However, the generation of such gas during combustion is likely to have a fatal effect on the human body. In particular, polybrominated diphenyl ethers, which are mainly halogen-based flame retardants, have a high possibility of generating very toxic gases such as dioxins and difurans during combustion.

According to US Pat. Nos. 4,692,488 and 5,204,394, a composition in which the aromatic phosphate ester compound is applied to a blend of polycarbonate and acrylonitrile-styrene-butadiene resin and polytetrafluoroethylene is added to achieve the properties of UL94 V-0. However, according to the above patent composition, it is difficult to attain physical properties of V-0 or V-1 at a polycarbonate content of 60 parts by weight or less due to the characteristics of the aromatic phosphate ester itself.

In addition, according to Japanese Patent Application Laid-Open No. 7-48,491, a thermoplastic flame-retardant resin was prepared by adding a phenolic resin and a phosphate ester in the form of a novolak to a thermoplastic copolymer resin of a rubbery polymer and an aromatic vinyl monomer. Not only the physical properties of UL94 V-1 or V-0 are difficult, but also the heat resistance is drastically lowered to secure practical heat resistance, which has not been commercialized yet. Practical heat resistance refers to heat resistance applied to electrical and electronic equipment. In general, the monitor housing of a computer should be maintained at a minimum of 85 ° C at a load of 5 kg according to ASTM D-1525.

In order to solve the drawbacks of the thermoplastic flame-retardant resin composition as described above, the inventors of the present invention provide a rubber-modified styrene-based resin containing a phenolic resin, a hindered phenolic PPE-based resin, and an aromatic phosphate ester or a flame retardant further containing a fluororesin. A resin composition with excellent heat resistance was developed and patented as Korean Patent Application No. 98-12220 (filed on April 7, 1998).

The patent application No. 98-12220 was able to develop a resin composition having good flame retardant properties by mixing phenol, PPE, phosphate ester and PTFE in a rubber modified styrene resin. However, this resin composition did not completely improve the compatibility between the PPE resin and the rubber modified styrene resin (ABS). That is, since this resin composition has a large difference in compatibility and Tg between PPE and ABS, the ABS melts first, which causes poor mixing, and further causes physical property defects.

According to the Journal of Applied Polymer Science 1998, 68, 1067, rubber-modified styrene resin (ABS) is hard to expect flame retardant effect in solid phase when it does not contain halogen which shows flame retardant effect in gaseous phase with little char remaining during combustion. There are disadvantages. Therefore, according to the above paper and Japanese Patent Application Laid-open No. Hei 7-48491, phosphate ester is applied as a flame retardant to a thermoplastic copolymer resin such as a high molecular weight polymer and an aromatic vinyl monomer, and a novolak type phenol resin is added as a char forming agent. Although thermoplastic flame retardant resins have been prepared, phenolic resins alone have a disadvantage in that the heat resistance is lowered because a relatively large amount of phosphate ester and novolak resin must be added to obtain a desired flame retardancy.

The polyphenylene ether-based resin applied to the composition of Patent Application No. 98-12220 has a glass transition temperature of 200 ° C. or more, and generally has a very high viscosity, and in particular, its mechanical properties are very low because of its low compatibility with ABS resins. Has the disadvantage of deterioration. Conventional polyphenyl ether resin composition is easy to manufacture a flame retardant resin when the polyphenyl ether content is high, but when the resin blend is processed, the phosphate ester compound applied as an ABS resin and a flame retardant is first melted when the polyphenylene ether content is low. Since it acts as a lubricant of phenylene ether, it is difficult to melt polyphenylene ether, kneading is not good, the physical properties of the final resin is not maintained constant, and there is a problem that the efficiency is relatively lowered in the flame retardant part. Therefore, when processing a low content polyphenylene ether-containing resin by using an existing extrusion method, the resin is manufactured by designing a screw to increase the processing temperature or to act a lot of shear force. However, in this case, since the resin temperature increases a lot, the possibility of volatilization of a highly vaporizable phosphate ester compound becomes very high when the temperature is higher than 250 ° C., thus causing a change in physical properties due to a change in the added content and the content of the phosphate ester compound in the prepared resin. The probability is very high. In addition, it is common to apply a vacuum to the machine to remove the gas generated during the extrusion process, in which case the pressure is lowered and the volatilization amount of the phosphate ester compound becomes larger. In addition, even if the processing temperature is higher than 250 ℃, if the vacuum is not applied during the extrusion process, the amount of volatilized phosphate ester is greatly reduced, so that the difference between the content and the amount of the phosphate ester in the final resin may be hardly observed. Incomplete unreacted monomer or other impurity gas generated during the process is contained in the pellets and exists in the form of bubbles, so appearance defects such as silver streak on the surface during the manufacture of the final product such as injection process It has a fatal weakness that can cause it.

MEANS TO SOLVE THE PROBLEM This inventor applied the phosphate ester compound as a flame retardant with respect to ABS resin, and smoothly kneaded | mixed and commercialized the polyphenylene ether resin which differs significantly in compatibility with the thermoplastic flame-retardant resin composition which injected phenol resin and polyphenylene ether as a char forming agent. In order to improve the performance, the high-quality polyphenylene ether resin blend having a specific composition is first processed to improve the compatibility, and then the ABS resin and other essential additives are added and the second process is excellent in kneading property and the phosphate ester compound of It has led to the development of a process for producing resins with little loss.

An object of the present invention is to provide a method for producing a thermoplastic resin composition excellent in flame retardancy.

Another object of the present invention is to provide a method for producing a thermoplastic resin composition excellent in heat resistance.

Still another object of the present invention is to provide a method for producing a thermoplastic flame retardant resin composition which improves the mixing of each component through a two-step extrusion process and further improves physical properties of the resin such as flame retardancy.

The above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

The thermoplastic flame retardant resin composition of the present invention is a rubber-modified styrene-based (ABS) base resin (A) consisting of a styrene-containing graft copolymer (g-ABS) resin (a ₁ ) and a styrene-containing copolymer (SAN) resin (a ₂ ). ), A phenol resin (B), a PPE resin (C) having a hindered phenol structure, and an aromatic phosphate ester (D). In the flame retardant resin composition of the present invention, phenol resin (B) and PPE resin (C) are used as char forming agents.

First, the components of the resin composition of the present invention will be described in detail.

(A) Rubber modified styrene base resin (ABS)

The rubber-modified styrenic base resin means a styrene-containing graft copolymer resin such as ABS, and the styrene-containing graft copolymer resin may contain a styrene-containing copolymer resin such as SAN.

Rubber modified styrene resin refers to a polymer in which a rubber polymer is dispersed in the form of particles in a matrix (continuous phase) made of a vinyl aromatic polymer, and an aromatic vinyl monomer and a vinyl monomer copolymerizable with the aromatic polymer in the presence of a rubber polymer. It is prepared by adding and polymerizing. Such rubber-modified styrene-based resins can be produced by known polymerization methods such as emulsion polymerization, suspension polymerization, and bulk polymerization, and usually produce styrene-containing graft copolymer resin and styrene-containing copolymer resin by mixed extrusion. In the case of bulk polymerization, the rubber-modified styrene resin is produced by only one step reaction without producing the styrene-containing graft copolymer resin and the styrene-containing copolymer resin separately. 5-30 weight part is suitable with respect to the whole base resin. Examples of such resins are acrylonitrile-butadiene-styrene copolymer resins (ABS), acrylonitrile-acryl rubber-styrene copolymer resins (AAS), acrylonitrile-ethylenepropylene rubber-styrene copolymers (AES) resins Etc.

Examples of the above resin may be applied to the styrene-containing graft copolymer resin alone or in combination of the styrene-containing graft copolymer resin and the styrene-containing copolymer resin, and is preferably blended in consideration of their compatibility.

(a ₁ ) Styrene-containing graft copolymer resin (g-ABS)

Examples of the rubber used for the styrene-containing graft copolymer resin include diene rubbers such as polybutadiene, poly (styrene-butadiene), and poly (acrylonitrile-butadiene); Saturated rubber hydrogenated to the diene rubber; Acrylic rubbers such as isoprene rubber, chloroprene rubber, and butyl polyacrylate; And ethylene-propylene-diene monomer terpolymers (EPDM) and the like, but especially diene rubber is preferred, and more preferably butadiene rubber is suitable.

As the aromatic vinyl monomer in the graft polymerizable monomer mixture, styrene, α-methyl styrene, p-methyl styrene, and the like may be added, of which styrene is most preferred, and the monomer copolymerizable with the aromatic vinyl monomer may be added thereto. Apply at least one of them. As a monomer which can be introduced, vinyl cyanide-based compounds such as acrylonitrile and unsaturated nitrile-based compounds such as methacrylonitrile are preferable.

Among the components of the styrene-containing graft copolymer as a whole, the rubber is 10 to 60% by weight, the aromatic vinyl monomer grafted to the rubber is 30 to 70% by weight, and the unsaturated nitrile monomer is 10 to 30% by weight. . Further, in order to impart properties such as workability and heat resistance, graft polymerization may be performed by adding monomers such as acrylic acid, methacrylic acid, maleic anhydride, and N-substituted maleimide. The amount added is in the range of 0 to 20 parts by weight based on the entirety of the styrene-containing graft copolymer resin.

In the production of the styrene-containing graft copolymer, in consideration of the impact strength and appearance, the average size of the rubber particles is suitably in the range of 0.1 to 4㎛.

(a ₂ ) Styrene-containing copolymer resin (SAN)

Styrene-containing copolymer resin is prepared according to the monomer ratio and compatibility among the components of the styrene-containing graft copolymer prepared in the above composition except rubber, the components are as follows.

As the aromatic vinyl monomer to be copolymerized, styrene, α-methyl styrene, p-methyl styrene, and the like may be added, of which styrene is most preferred, and the weight ratio of the aromatic vinyl monomer in the components of the entire copolymer resin is 60 to 95 parts by weight. Corresponds to One or more monomers copolymerizable with the aromatic vinyl monomers described above are introduced and applied thereto. As the monomer to be introduced, vinyl cyanide-based compounds such as acrylonitrile and unsaturated nitrile-based compounds such as methacrylonitrile are preferable, and 40 to 5 parts by weight of the components of the entire copolymer are introduced. Furthermore, 0-40 weight part of monomers, such as acrylic acid, methacrylic acid, maleic anhydride, and N-substituted maleimide, can also add and copolymerize here.

SAN resin having an AN content of 5 to 20% by weight is used in the first extrusion process. The reason why the AN content of the SAN resin is maintained at 5 to 20% by weight is that when the AN content is 5% by weight or less, the compatibility with the final ABS resin is lowered, resulting in poor mechanical properties, and the AN content is 20% by weight. In the above case, since the compatibility with the polyphenylene ether resin itself, which is a char forming agent, is lowered and shows no compatibility with ABS, extrusion is difficult and the mechanical properties of the final resin are not preferable. The primary extrusion process adds a high content of polyphenylene ether resin blend pellets having a glass transition temperature of 90 to 150 ° C., a SAN resin having a AN content of 20 to 40 wt%, a phenol resin, and additional phosphate esters. To obtain a final resin by processing under a vacuum at a temperature of 200 to 260 ℃ extrusion temperature.

(B) phenolic resin

In the flame retardant resin composition of the present invention, phenol resin (B) and PPE resin (C) are used as char forming agents. Char is produced by forming three-dimensional carbon chain bonds during combustion, and since ordinary rubber-modified styrene resin hardly generates char when burning, the char forming agent effectively removes char from the surface of the polymer when burning. It blocks the ingress of oxygen from the outside and prevents the release of fuel from the inside. The char forming agent is classified into a phenolic resin (B) having an effect in a low temperature region and a polyphenylene ether resin (C) having a char forming and reinforcing role at a high temperature.

Phenolic resins are classified into resol type phenol resins and novolac type phenol resins, and both of them may be used in the present invention. In addition, the phenol resin may be classified into a thermosetting resin and a thermoplastic resin, all of which may be used. In the present invention, novolak phenol resins are more preferably used than resol phenol resins.

As the novolak-based phenol resin, phenol formaldehyde novolak resin, tertiary butyl phenol formaldehyde novolak resin, paraoctyl phenol formaldehyde novolak resin, paracyano phenol formaldehyde novolak resin, etc. may be applied. Copolymers may also be used. The novolak-based phenol resin preferably has an average molecular weight of about 300 to 10,000.

The phenol resin is 5 to 30 parts by weight based on the rubber modified styrene resin. When the phenol resin is used in less than 5 parts by weight it is difficult to impart flame retardancy, and when applied to more than 30 parts by weight, mechanical properties and thermal properties are lowered and difficult to apply.

(C) Hindered phenolic polyphenylene ether (PPE) resin

The polyphenylene ether resin is obtained by applying a hindered phenol as a monomer, poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether , Poly (2,6-dipropyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly (2-methyl-6-propyl-1, 4-phenylene) ether, poly (2-ethyl-6-propyl-1,4-phenylene) ether, poly (2,6-diphenyl-1,4-phenylene) ether, poly (2,6- Copolymer of dimethyl-1,4-phenylene) ether and poly (2,3,6-trimethyl-1,4-phenylene) ether, and poly (2,6-dimethyl-1,4-phenylene) ether And a copolymer of poly (2,3,5-triethyl-1,4-phenylene) ether. Preferably a copolymer of poly (2,6-dimethyl-1,4-phenylene) ether and poly (2,3,6-trimethyl-1,4-phenylene) ether and poly (2,6-dimethyl- 1,4-phenylene) ether is used, more preferably poly (2,6-dimethyl-1,4-phenylene) ether. Although the polymerization degree of polyphenylene ether is not specifically limited, It is preferable that the intrinsic viscosity measured in 25 degreeC chloroform solvent is 0.2-0.8 in consideration of the thermal stability and workability of a resin composition. These polyphenylene ethers may be used alone or in combination of two or more thereof in an appropriate ratio.

The polyphenylene ether resin may be used in an amount of 5 to 40 parts by weight based on the rubber-modified styrene resin which is a basic resin.

(D) Aromatic Phosphate Ester

Phosphate esters that can be used in the present invention are compounds having the structure of the following formula (I): Phosphate esters corresponding thereto include tri (2,6-dimethylphenyl) phosphate, tri (2,6-dibutylbutylphenyl) phosphate, and the like. have.

Structural Formula Ⅰ

In Formula I, R ₁ , R ₂ and R ₃ are independently hydrogen or an alkyl or phenyl structure having 1 to 6 carbon atoms and may be the same or different from each other.

In the present invention, a phosphate ester compound represented by the following structural formula II can also be used.

Structural Formula II

In Formula II, R ₄ , R ₅ and R ₆ are each independently hydrogen or an alkyl or phenyl structure having 1 to 6 carbon atoms, X is an aryl or alkylaryl structure having 6 to 20 carbon atoms, and N is less than 1 Greater than or equal to

Compounds corresponding to the above formula II include resorcinol bis [di (2,6-dimethylphenyl) phosphate], hydrokinol bis [di (2,6-dimethylphenyl) phosphate], biphenyl bis [di (2,6) -Dimethylphenyl) phosphate], resorcinolbis [di (2,6-dibutylbutylphenyl) phosphate], hydrokinolbis [di (2,6-dibutylbutylphenyl) phosphate], biphenylbis [di ( 2,6-dibutylbutylphenyl) phosphate].

In the present invention, a phosphate ester compound represented by the following structural formula III having phloroglucinol as a skeleton may also be used.

Structural Formula Ⅲ

In Formula III, R ₇ , R ₈ and R ₉ are each independently hydrogen or an alkyl or phenyl structure having 1 to 6 carbon atoms.

Examples of the structural formula III include 1,3,5-tri (2,6-dimethylphenylphosphate) fluoroglucinol and 1,3,5-tri (2,6-dibutylbutylphenylphosphate) fluoroglucinol. There is this.

Phosphoric acid ester having the above structural formula may be applied singly or mixed, but it is not preferable to apply a compound having a molecular weight of 1,500 or more in the structure because the effect of imparting flame retardancy is small. Preferably, the phosphate ester whose melting | fusing point is 80 degreeC or more is applied.

It is preferable to use the aromatic phosphate ester compound applied as a flame retardant in this invention in the range of 5-30 weight part with respect to the rubber modified styrene resin of this invention.

In addition to the above components, the resin composition of the present invention may further include a fluororesin. The fluororesin is polytetrafluoroethylene, polyvinylidene fluoride, copolymer of tetrafluoroethylene and vinylidene fluoride, copolymer of tetrafluoroethylene and fluoroalkyl vinyl ether, and tetrafluoroethylene There is a copolymer of hexafluoropropylene. These may be used independently from each other, or a mixture of two or more different from each other may be used. The fluororesin forms a fibrillar network in the resin when it is mixed with the resin and extrudes, thereby reducing the flow viscosity of the resin during combustion and increasing the shrinkage rate to prevent the dropping of the resin. The use of an fluororesin in an emulsion state has the advantage of good dispersibility of the fluorine-based resin with respect to the entire resin, but has a disadvantage in that the process is complicated. Therefore, even in a powder state, it can be preferably applied as long as it can be properly dispersed in the whole resin to form a fibrous net. Preferred fluorine resins may be polytetrafluoroethylene. The amount of fluorine resin that can be preferably used in the present invention is 0.01 to 2.0 parts by weight based on the rubber modified styrene resin.

The composition may be added plasticizers, heat stabilizers, antioxidants, light stabilizers and the like as needed, and may be added organic or inorganic pigments and dyes, inorganic fillers such as talc, silica, mica, glass fibers, and the like.

The method for preparing a thermoplastic flame retardant resin composition of the present invention comprises the steps of first extrusion by mixing polyphenylene ether (PPE) resin, styrene-containing copolymer (SAN) and aromatic phosphate ester and the first extruded masterbatch And styrene-containing copolymer (SAN), styrene-containing graft copolymer resin (g-ABS), aromatic phosphate ester and phenol, followed by secondary extrusion. The SAN used in the first extrusion step preferably contains 5 to 20% by weight of acrylonitrile (AN), and the resin produced in the first extrusion step has a glass transition temperature (Tg) of 90 to 150 ° C. It is preferable to have).

(1) First Extrusion

The purpose of the first extrusion is to maintain a stable phase stability in the final kneading and final composition of the polyphenylene ether resin added as a char forming agent. Since the polyphenylene ether resin itself is a high-performance polymer having a glass transition temperature of 200 to 210 ° C., the polyphenylene ether resin has a difference of 100 ° C. or more from the glass transition temperature of ABS itself, and thus it is very difficult to produce good phase stability with a single extrusion process. Therefore, a resin blend of polyphenylene ether having a high content is prepared by primary extrusion, and the glass transition temperature of the blend is controlled to be in the range of 90 to 150 ° C. similar to the glass transition temperature of the ABS resin itself.

40 to 90 parts by weight of polyphenylene ether, 10 to 40 parts by weight of SAN resin having an AN content of 5 to 20% by weight, and 5 to 20 parts by weight of aromatic phosphate ester are added to a processing aid or an antioxidant, and the extrusion temperature is 250 to It manufactures in the range of 310 degreeC. The reason why the AN content of the SAN resin is maintained at 5 to 20% by weight is that when the AN content is 5% by weight or less, the compatibility with the final ABS resin is lowered, resulting in poor mechanical properties, and the AN content is 20% by weight. In the above case, since the compatibility with the polyphenylene ether resin itself, which is a char forming agent, is lowered and shows no compatibility with ABS, extrusion is difficult and the mechanical properties of the final resin are not preferable. Aromatic phosphate esters have excellent performance in improving processability and imparting plasticity of polyphenylene ether. Thus, an appropriate amount of phosphate ester is added to prepare a glass transition temperature of 90-150 ° C. in the final resin blend. The amount of phosphate ester used is 5 to 20 parts by weight.

In the first processing, preferably, no vacuum is applied during extrusion. The reason for not applying the vacuum is to minimize the loss of volatile phosphate ester because the extrusion temperature is maintained at a high temperature for melting the polyphenylene ether during the first processing.

(2) Second Extrusion

The first process was performed by adding a high content of polyphenylene ether resin blend pellets having a glass transition temperature of 90 to 150 ℃, AN resin of 20 to 40% by weight, phenol resin and additional phosphate ester The final resin is prepared by subjecting the extrusion to a vacuum at a temperature of 200 to 260 ° C., followed by secondary processing.

The composition of the resin produced by the first and second extrusion processing is 5 to 30 parts by weight of phenol resin, 5 to 40 parts by weight of polyphenylene ether resin as a char forming agent, based on 100 parts by weight of ABS resin, which is a basic resin. Part is applied and has a content of 5 to 30 parts by weight of the phosphate ester as a flame retardant. In the second extrusion step, a small amount of fluororesin may be added.

In the thermoplastic resin manufacturing method of the present invention, an antidrip agent, an impact modifier, an inorganic additive, a heat stabilizer, an antioxidant, a light stabilizer, a pigment, and / or a dye may be added according to each use. The inorganic additives to be added include asbestos, glass fibers, talc, and ceramics, which can be used in the range of 0 to 30 parts by weight with respect to 100 parts by weight of the basic resin of the present invention, and are used in the conditions of primary or secondary extrusion. Can be injected accordingly.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

In Examples 1 and Comparative Examples 1 to 4 described below, the present invention consists of (A) basic resin, (B) phenol resin, (C) hindered phenolic polyphenylene ether resin, and (D) aromatic phosphate ester. The Example of the resin composition of this invention, and the comparative example for comparing it are shown.

(A) Basic resin

(a ₁ ) Styrene-containing graft copolymer resin (g-ABS)

Butadiene rubber latex is 50 parts by weight in solid content, 36 parts by weight of styrene, 14 parts by weight of acrylonitrile and 150 parts by weight of deionized water are added as monomers for grafting, 1.0 parts by weight of potassium oleate and total cumene hydroperoxide 0.4 Part, 0.2 part by weight of mercaptan-based chain transfer agent, 0.4 part by weight of glucose, 0.01 part by weight of iron sulfate hydrate, and 0.3 part by weight of sodium pyrophosphate were maintained at 75 ° C. for 5 hours, and the reaction was completed to prepare graft ABS latex. Subsequently, 0.4 parts by weight of sulfuric acid was added to the solid content of the resin and solidified to prepare a styrene-containing graft copolymer resin (g-ABS) powder.

(a ₂ ) Copolymer Resin (SAN)

(a ₂₁ ) SAN copolymer resin I (AN content 25% by weight)

75 parts by weight of styrene, 25 parts by weight of acrylonitrile, 120 parts by weight of deionized water, 0.15 part by weight of azobisisobutyronitrile, 0.4 part by weight of tricalcium phosphate, and 0.2 part by weight of mercaptan-based chain transfer agent, followed by 80 at room temperature. The copolymer resin (SAN) having an acrylonitrile content of 25% by weight was prepared by increasing the temperature to 90 DEG C for 90 minutes and maintaining the temperature for 180 minutes at this temperature. It is washed with water, dehydrated and dried to prepare a SAN powder. The weight average molecular weight of the synthesized styrene acrylonitrile copolymer resin corresponds to about 120,000 to 200,000.

(a ₂₂ ) SAN copolymer resin II (AN content 13% by weight)

87 parts by weight of styrene, 13 parts by weight of acrylonitrile, 120 parts by weight of deionized water, 0.1 part by weight of azobisisobutyronitrile, 1,1'-di (tertiarybutylperoxy) -3,3 ', 5 -0.2 parts by weight of trimethylcyclohexane, 0.4 parts by weight of tricalcium phosphate, and 0.2 parts by weight of mercaptan-based chain transfer agent were heated at room temperature to 80 ° C. for 90 minutes, maintained at this temperature for 150 minutes, and then heated up to 95 ° C. It is maintained for 120 minutes to prepare a copolymer resin (SAN) having an acrylonitrile content of 13%. It is washed with water, dehydrated and dried to prepare a SAN powder. The weight average molecular weight of the synthesized styrene acrylonitrile copolymer resin corresponds to about 90,000 to 120,000.

(B) phenolic resin

Phenol Novolac phenolic resin of PSM 4324 Grade in Gunei, Japan was applied.

(C) Polyphenylene ether resin of hindered phenol skeleton

Poly (2,6-dimethyl-1,4-phenyl) ether of Asahi Kasei Co., Ltd., Japan, was used. The product is P-401 as a powder having an average particle diameter of several μm.

(D) Aromatic Phosphate Ester Compounds

Tri (2,6-dimethylphenyl) phosphate (trade name: PX-130) from Daihachi, Japan, was used.

Example 1

(1) First Extrusion

60 parts by weight of polyphenylene ether resin, 40 parts by weight of a SAN copolymer resin (a ₂₂ ) having an acrylonitrile content of 13% by weight and phosphate ester based on a total of 100 parts by weight of polyphenylene ether resin and a SAN copolymer resin. 10 parts by weight was added to a conventional twin screw extruder, the extruder cylinder temperature was maintained at 280 ° C., and melt kneaded without applying a vacuum in the extruder to prepare pellets. The glass transition temperature of the resin blend prepared by the first extrusion process showed a value of 125 ° C.

(2) Second Extrusion

36.7 parts by weight of a blend of a high content of polyphenylene ether and a SAN copolymer resin (a ₂₂ ), firstly processed, and a SAN copolymer resin containing 40 parts by weight of a graft copolymer resin and a content of 25% by weight of acrylonitrile (a ₂₁ ) 46.65 parts by weight, phenol resin 15 parts by weight, phosphate ester 16.7 parts by weight, and antioxidant and processing aid pigments were added, melt-kneaded while maintaining the temperature and vacuum of 230 ℃ sufficiently in a twin screw extruder Was prepared.

Comparative Example 1

(1) First Extrusion

Except for applying a SAN copolymer resin (a ₂₂ ) having an acrylonitrile content of 13% by weight during the first extrusion process of Example 1, except applying a SAN copolymer resin having an acrylonitrile content of 25% by weight. And other conditions were processed the same.

(2) Second Extrusion

The same content and conditions as those of the second extrusion process of Example 1 were used.

Comparative Example 2

60 parts by weight of the SAN copolymer resin (a ₂₁ ), 40 parts by weight of the graft copolymer resin, 20 parts by weight of polyphenylene ether resin, 15 parts by weight of phenol resin, and 20 parts by weight of phosphate ester were added at a temperature of 280 ° C. in a twin screw extruder. It was prepared under vacuum only by primary processing at temperature.

Comparative Example 3

60 parts by weight of the SAN copolymer resin (a ₂₁ ), 40 parts by weight of the graft copolymer resin, 20 parts by weight of polyphenylene ether resin, 15 parts by weight of phenol resin, and 20 parts by weight of phosphate ester were added at a temperature of 280 ° C. in a twin screw extruder. It was prepared without applying a vacuum only by primary processing at temperature.

Comparative Example 4

60 parts by weight of the SAN copolymer resin (a ₂₂ ), 40 parts by weight of the graft copolymer resin, 20 parts by weight of polyphenylene ether resin, 15 parts by weight of phenol resin, and 20 parts by weight of phosphate ester were added at a temperature of 280 ° C. in a twin screw extruder. It was prepared without applying a vacuum only by primary processing at temperature.

The pellets prepared as above were dried at 80 ° C. for 3 hours and then injected into a 6 Oz injection machine under molding temperature of 220 to 280 ° C. and mold temperature of 60 to 90 ° C. to prepare a physical specimen. The fabricated specimens were flame retardant in accordance with UL 94 VB, Izod impact strength (1/8 "notch) in accordance with ASTM D256, beetle softening temperature, and the appearance of the molded part was visually or microscopically observed. Check for the presence of lene ether.

Item Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Izod impact strength (1/8 ") 18 3.2 2.3 2.5 4.2 Bicket Softening Temperature ^* 87 87 90 88 88 UL94 VB (1/8 ") ^** V-1 V-1 Fail V-1 V-1 Beauty PPE present None None Large quantities Large quantities Large quantities Surface defect (silver line etc) Good Good Good Bad Bad

Note) Viket softening temperature ^* : Measured under 5kg load according to ASTM D-1525

The result is.

Flame retardant ^** : Measured according to UL94 VB flame retardant standard.

The results of Example 1 show good physical properties without any defects in mechanical strength, flame retardancy, appearance, and the like. That is, the PPE is sufficiently melted and kneaded well during the first processing, and since the SAN copolymer resin having an atrylonitrile content of 13% by weight is applied, it has some compatibility with the PPE and further acrylonitrile. The final physical properties of the resin prepared through secondary processing by adding a SAN copolymer resin and graft resin having a content of 25% by weight shows very good performance.

In Comparative Example 1, all of the SAN copolymers applied in comparison with Example 1 were 25% by weight of acrylonitrile resin, but the flame retardant heat resistance and appearance were not different from those of Example 1, but polyphenylene ether In spite of being the same component due to the incompatibility with the resin, the impact strength rapidly decreased.

In the case of Comparative Example 2, not only did the polyphenylene ether of high melting point be completely melted, but also the phosphate ester introduced at a temperature of 280 ° C. was volatilized, so that the heat resistance was high. The flame retardancy was not secured. In addition, since the compatibility with the polyphenylene ether is not secured, the impact strength also decreases rapidly.

Comparative Example 3 was prepared under the same conditions as in Comparative Example 2 without the loss of phosphate esters applied as a flame retardant was able to maintain the flame retardancy, but also shows a poor mechanical properties and appearance.

Comparative Example 4 was applied to only the acrylonitrile content of 13% by weight to show some compatibility with the polyphenylene ether to improve the impact strength to some extent, but the appearance is not good.

The present invention has the effect of the invention for providing a method for producing a thermoplastic flame retardant resin composition to improve the mixing of each component through a two-step extrusion process, and further improved the physical properties of the resin, such as flame retardancy.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (9)

A flame-retardant resin composition comprising a rubber-modified styrenic base resin, a phenol resin, a polyphenylene ether resin having a hindered phenol structure, and an aromatic phosphate ester composed of a styrene-containing graft copolymer resin and a styrene-containing copolymer resin In the method, A first extrusion step of mixing and extruding a polyphenylene ether (PPE) resin having a hindered phenol structure, a styrene-containing copolymer (SAN), and an aromatic phosphate ester; And A second extrusion step of mixing and extruding a styrene-containing copolymer (SAN), a styrene-containing graft copolymer resin (g-ABS), an aromatic phosphate ester, and a phenol resin to the first extruded masterbatch; The SAN used in the first extrusion step contains 5 to 20% by weight of acrylonitrile (AN), and the SAN used in the second extrusion step is 20 to 40% by weight of acrylic. Nitrile (AN), the resin produced in the first extrusion step has a glass transition temperature (Tg) of 90 ~ 150 ℃ characterized in that the method for producing a thermoplastic flame retardant resin composition. The thermoplastic flame retardant resin according to claim 1, wherein in the first extrusion step, the polyphenylene ether is 40 to 90 parts by weight, SAN is 10 to 40 parts by weight, and aromatic phosphate ester is 5 to 20 parts by weight. Method of Preparation of the Composition. The method of claim 1, wherein the first extrusion step is performed at an extrusion temperature of 250 to 310 ° C. without applying a vacuum, and the second extrusion step is performed at an extrusion temperature of 200 to 250 ° C. in a vacuum state. A method for producing a thermoplastic flame retardant resin composition. The method for preparing a thermoplastic flame retardant resin composition according to claim 1, wherein a small amount of g-ABS is added in the first extrusion step. The method of manufacturing a thermoplastic flame retardant resin composition according to claim 1, wherein a small amount of fluorine resin is added in the second extrusion step. The method for producing a flame-retardant thermoplastic resin composition containing no halogens according to claim 1, wherein the phenol resin is a novolac phenol resin. The polyphenylene ether resin of claim 1, wherein the polyphenylene ether resin is poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, poly ( 2,6-dipropyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly (2-methyl-6-propyl-1,4-phenyl Ethylene) ether, poly (2-ethyl-6-propyl-1,4-phenylene) ether, poly (2,6-diphenyl-1,4-phenylene) ether, poly (2,6-dimethyl-1 Copolymer of, 4-phenylene) ether and poly (2,3,6-trimethyl-1,4-phenylene) ether, and poly (2,6-dimethyl-1,4-phenylene) ether and poly A method for producing a halogen-free flame retardant thermoplastic resin composition, which is selected from the group consisting of copolymers with (2,3,5-triethyl-1,4-phenylene) ether. The method of claim 1, wherein the aromatic phosphate ester is selected from the group consisting of the following structural formulas (I), (II) and (III): Structural Formula Ⅰ In Formula I, R ₁ , R ₂ and R ₃ are each independently hydrogen or an alkyl or phenyl structure having 1 to 6 carbon atoms, Structural Formula II In Formula II, R ₄ , R ₅ and R ₆ are each independently hydrogen or an alkyl or phenyl structure having 1 to 6 carbon atoms, X is an aryl or alkylaryl structure having 6 to 20 carbon atoms, and N is less than 1 Greater than or equal to Structural Formula Ⅲ R ₇ , R ₈ and R ₉ in Formula III are each independently hydrogen or an alkyl or phenyl structure having 1 to 6 carbon atoms. A thermoplastic flame retardant resin composition prepared according to the method according to any one of claims 1 to 8.