JP2002088165A - Flame-retardant resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-retardant resin molded product having excellent flame retardance and excellent quality stability. SOLUTION: This flame retardant resin molded product is characterized in that the molded product is obtained by dissolving carbon dioxide in a resin composition comprising an aromatic polycarbonate or a resin consisting essentially of the aromatic polycarbonate and one or more kinds of nonhalogen flame retardants selected from phosphorus, nitrogen, sulfur and inorganic flame retardants, thereby reducing the melt viscosity and molding the resultant melt. Furthermore, the resin molded product is especially characterized by previously keeping a metal mold cavity in a pressurized state of a pressure not lower than that without causing the foaming in the flow front of the molten resin and injection molding the molten resin composition having the melt viscosity reduced by dissolving the carbon dioxide into the metal mold cavity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant resin molded article. More specifically, a flame-retardant resin molding having high flame retardancy, excellent impact resistance, and quality stability obtained from a resin composition comprising an aromatic polycarbonate and a specific non-halogen flame retardant by a specific processing method. It is about the body.

[0002]

2. Description of the Related Art Aromatic polycarbonate is superior to glass and metal in terms of moldability and impact resistance. However, its use is limited due to the flammability of aromatic polycarbonate. As a method of making a polymer flame-retardant, it is known to add a halogen-based, phosphorus-based, or inorganic-based flame retardant to the polymer, thereby achieving some degree of flame retardancy. However, in recent years, the demand for fire safety has been particularly noticed, and with the development of more advanced flame retardant technology, there is a strong demand for technology development that does not cause environmental problems or decrease in mechanical properties. Against this background, flame-retardant resin moldings using non-halogen flame retardants have been developed.
Since the aromatic polycarbonate has a high melt viscosity, it generates a considerable amount of heat when molding a molded article, and has a disadvantage that it cannot withstand practical use because it promotes decomposition of the flame retardant or the aromatic polycarbonate.

[0003] Also, US Pat. No. 4,990,595 discloses a resin containing no gas after melting two or more resins such as polycarbonate in the presence of a supercritical gas and mixing them sufficiently until the viscosity is reduced by at least 10%. A method for producing a highly dispersed resin mixture by cooling to a viscosity equal to or higher than that and releasing the pressure is disclosed. In addition, WO98
/ 52734 pamphlet discloses an injection molding method in which carbon dioxide is blown during injection molding of a thermoplastic resin and can be melt-molded at a low temperature. However, both the above publications do not disclose the molding of an aromatic polycarbonate resin composition containing a non-halogen flame retardant, but do not even suggest that excellent flame retardancy is exhibited.

[0004]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a flame-retardant resin molded article which does not have the above-mentioned problems, that is, has excellent flame retardancy and excellent quality stability. It is intended to provide.

[0005]

Means for Solving the Problems As a result of intensive studies on an excellent flame-retardant resin molded product, the present inventors have found that a particular flame-retardant aromatic polycarbonate can be surprisingly processed by a particular processing method. In particular, they have found that quality stability and flame retardancy can be dramatically improved, and have completed the present invention. That is, the present invention relates to a resin composition comprising an aromatic polycarbonate or a resin mainly composed of an aromatic polycarbonate and one or more non-halogen flame retardants selected from phosphorus, nitrogen, sulfur and inorganic flame retardants. A flame-retardant resin molded article obtained by molding by lowering the melt viscosity by dissolving carbon, in particular, the molten resin composition in which carbon dioxide is dissolved to lower the melt viscosity By injecting the mold cavity into the mold cavity in advance by pressurizing the mold cavity with carbon dioxide at a pressure higher than the pressure at which foaming does not occur at the flow front of the molten resin. A molded article is provided.

Hereinafter, the present invention will be described in detail. The molded article of the present invention is a flame retardant obtained by subjecting a resin composition comprising (A) an aromatic polycarbonate or a resin mainly composed of an aromatic polycarbonate and (B) a specific non-halogen flame retardant to specific processing. It is a resin molding. In general, aromatic polycarbonates generate remarkable heat when molding a molded article due to a high melt viscosity, and promote the decomposition of a flame retardant or an aromatic polycarbonate.
Or, the molded product has poor glossiness, poor appearance, flame retardancy, and poor quality stability of physical properties. Here, it is important to dissolve carbon dioxide in the resin composition composed of (A) and (B) to lower the melt viscosity and mold the resin composition. In particular, it is preferable to lower the shear melt viscosity by 10% or more by dissolving carbon dioxide with respect to the shear melt viscosity when carbon dioxide is not dissolved in the resin composition. By dissolving carbon dioxide in the molten resin, the carbon dioxide acts as a plasticizer only during molding, and the molded product does not deform after the molding and is released into the atmosphere. It has been found that the viscosity can be reduced and molding can be facilitated, and the present invention has been completed.

In the present invention, (A) is an aromatic polycarbonate (hereinafter referred to as PC) or a resin mainly composed of PC. The aromatic polycarbonate (PC) is
It can be selected from aromatic homopolycarbonate and aromatic copolycarbonate. The production method includes a phosgene method in which phosgene is blown into a bifunctional phenolic compound in the presence of a caustic alkali and a solvent, or a transesterification method in which a bifunctional phenolic compound is transesterified with diethyl carbonate in the presence of a catalyst. Can be mentioned. The aromatic polycarbonate has a viscosity average molecular weight of 1
A range of 10,000 to 100,000 is preferable. Here, the bifunctional phenol compound is 2,2'-bis (4-hydroxyphenyl) propane, 2,2'-bis (4-hydroxy-3,5-dimethylphenyl) propane, bis (4-hydroxyphenyl) propane. Phenyl) methane, 1,1′-bis (4-hydroxyphenyl) ethane, 2,2′-bis (4-hydroxyphenyl) butane, 2,2′-bis (4-hydroxy-3,5-diphenyl) butane , 2,2'-bis (4
-Hydroxy-3,5-dipropylphenyl) propane, 1,1'-bis (4-hydroxyphenyl) cyclohexane, 1-phenyl-1,1'-bis (4-hydroxyphenyl) ethane, and especially 2 , 2'-bis (4-hydroxyphenyl) propane [bisphenol A] is preferred. In the present invention, the bifunctional phenolic compounds may be used alone or in combination.

In the present invention, the polymer that can be blended with the PC is a rubber-like polymer, a thermoplastic resin other than PC, or a thermosetting resin.
Thermoplastic resins other than PC are preferred. In the present invention,
The thermoplastic resin other than PC is not particularly limited as long as it can be uniformly dispersed in (B). For example, polystyrene-based, polyphenylene ether-based, polyolefin-based, polyvinyl chloride-based, polyamide-based, polyester-based, polyphenylene sulfide-based, and polymethacrylate-based resins can be used alone or in combination of two or more. In the present invention, a resin composition containing a polystyrene-based, polyphenylene ether-based, or polyolefin-based thermoplastic resin and a rubber-like polymer in PC is particularly preferable. In the present invention, the polystyrene resin preferably blended with the PC is a rubber-modified styrene resin and / or a non-rubber-modified styrene resin, particularly a rubber-modified styrene resin alone or a rubber-modified styrene resin and a rubber-unmodified styrene resin. It is preferable to be made of a styrene resin.

The rubber-modified styrenic resin is a polymer obtained by dispersing a rubbery polymer in the form of particles in a matrix composed of a vinyl aromatic polymer. The monomer and, if necessary, a vinyl monomer copolymerizable therewith are added, and the monomer mixture can be obtained by known polymerization methods such as bulk polymerization, emulsion polymerization, and suspension polymerization. Examples of such polymers include high impact polystyrene (HIPS), ABS polymer (acrylonitrile-
Butadiene-styrene copolymer), AAS polymer (acrylonitrile-acrylic rubber-styrene copolymer), A
ES polymer (acrylonitrile-ethylene propylene rubber-styrene copolymer) and the like. Here, the rubbery polymer preferably has a glass transition temperature (Tg) of −30 ° C. or lower, and if it exceeds −30 ° C., the impact resistance tends to decrease. Examples of such rubbery polymers include diene rubbers such as polybutadiene, poly (styrene-butadiene), poly (acrylonitrile-butadiene), and saturated rubbers obtained by hydrogenating the diene rubber;
Acrylic rubbers such as isoprene rubber, chloroprene rubber, polybutyl acrylate, etc., ethylene-propylene copolymer rubber, ethylene-propylene-diene monomer terpolymer rubber (EPDM), ethylene-octene copolymer rubber, etc. And diene rubbers are particularly preferable.

The aromatic vinyl monomer as an essential component in the graft-polymerizable monomer mixture to be polymerized in the presence of the rubbery polymer is, for example, styrene, α-methylstyrene, paramethylstyrene, or the like. Yes, styrene is most preferred, but other aromatic vinyl monomers described above may be copolymerized mainly with styrene. If necessary, one or more monomer components copolymerizable with the aromatic vinyl monomer can be introduced as components of the rubber-modified styrene resin. When it is necessary to increase oil resistance, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile can be used. When it is necessary to lower the melt viscosity at the time of blending, an acrylate having an alkyl group having 1 to 8 carbon atoms can be used. Further, when it is necessary to further increase the heat resistance of the resin composition, α-methylstyrene, acrylic acid, methacrylic acid,
Monomers such as maleic anhydride and N-substituted maleimide may be copolymerized. The content of the vinyl monomer copolymerizable with the vinyl aromatic monomer in the monomer mixture is from 0 to 40.
% By weight. The rubber-like polymer in the rubber-modified styrenic resin is preferably 5 to 80% by weight, particularly preferably 10 to 50% by weight, and the graft-polymerizable monomer mixture is preferably 95 to 20% by weight, more preferably 90
５０50% by weight. Within this range, the balance between impact resistance and rigidity of the target resin composition is improved.
Further, the rubber particle diameter of the rubber-modified styrene resin is 0.1.
It is preferably from 1 to 5.0 μm, and particularly preferably from 0.2 to 3.0 μm. Within the above range, impact resistance is particularly improved. Reduced viscosity ηsp / c (0.5 g / dl, 30 ° C.) of the polymer portion, which is a measure of the molecular weight of the rubber-modified styrenic resin
Measurement: Toluene solution when the matrix resin is polystyrene, methyl ethyl ketone when the matrix resin is an unsaturated nitrile-aromatic vinyl copolymer) is 0.3
It is preferably in the range of 0 to 0.80 dl / g,
More preferably, it is in the range of 0.40 to 0.60 dl / g. Reduced viscosity ηsp / c of rubber-modified styrenic resin
Means for satisfying the above-mentioned requirements include adjustment of the amount of polymerization initiator, polymerization temperature, and amount of chain transfer agent.

Among the above-mentioned styrene resins, when heat resistance and oil resistance are particularly required, a syndiotactic styrene polymer which is a crystalline styrene polymer is preferable. In the present invention, when (A) is composed of PC and a polystyrene resin, the amount of PC in 100 parts by weight of (A) is 1 to 99% by weight, preferably 30 to 9% by weight.
It is 9% by weight, more preferably 50-90% by weight, most preferably 60-90% by weight. As polystyrene resin to be blended with PC, high impact polystyrene (H
IPS) and an ABS polymer (acrylonitrile-butadiene-styrene copolymer) are preferable. When the above HIPS is used, it is preferable to use a styrene-based copolymer as a compatibilizer from the viewpoint of compatibility with PC. For example, described in WO95-35346 pamphlet,
(A) a copolymer comprising an aromatic vinyl monomer and a monomer copolymerizable with the aromatic vinyl monomer; and (b) a rubbery polymer having a glass transition temperature (Tg) of -30 ° C or lower. And an aromatic vinyl monomer (M1) grafted thereon and a monomer copolymerizable with the aromatic vinyl monomer (M1) (M
2) at least one compatibilizer selected from the graft copolymers comprising the monomers (M1) and (M
2) may be a homopolymer thereof and / or may be copolymerized with each other, and the copolymer as the component (C) is a monomer constituting the copolymer. Having a non-uniform distribution with respect to the ratio of the monomer components, whereby the copolymer consists of copolymer molecules with different solubility parameter (SP) values, with the copolymer molecule having the largest SP value and the smallest SP between copolymer molecules having SP value
The value difference is 0.3 to 1.0 [(cal / cm ³ ) ^1/2 ], and the average SP value of the copolymer is 10.6 to 11.2.
A styrene copolymer satisfying [(cal / cm ³ ) ^1/2 ].

In the present invention, the polyphenylene ether-based resin preferably blended with PC is a polyether having an aromatic ring in the main chain. Specific examples of the polyphenylene ether-based resin include poly (2,6-dimethyl-1,4-phenylene ether), copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol. Merging is preferred, and poly (2,6-dimethyl-1,4-phenylene ether) is particularly preferred. Reduced viscosity ηs of the polyphenylene ether used in the present invention
p / c (0.5 g / dl, chloroform solution, measured at 30 ° C.) is preferably in the range of 0.20 to 0.70 dl / g, and preferably in the range of 0.30 to 0.60 dl / g. Is more preferred. As a means for satisfying the above requirements regarding the reduced viscosity ηsp / c of the polyphenylene ether, adjustment of the amount of a catalyst in the production of the polyphenylene ether and the like can be mentioned. In the present invention, the polyolefin-based resin preferably incorporated into the PC is a partially or completely crosslinked thermoplastic polymer composed of a crosslinkable rubber-like polymer and a polyolefin, and is, for example, a crosslinking agent, a crosslinking aid. Can be produced by dynamically crosslinking in the presence of The crosslinkable rubber-like polymer is preferably an ethylene-α-olefin copolymer, and ethylene and α-olefin having 3 to 20 carbon atoms.
-Olefin is more preferred, and particularly preferred is an ethylene-C6-C12 α-olefin copolymer produced using a metallocene catalyst. The above-mentioned polyolefin is preferably a propylene-based resin, and a homo-isotactic polypropylene, an isotactic copolymer resin of propylene and another α-olefin such as ethylene, butene-1, pentene-1, hexene-1 (block, (Including random).

In the present invention, the rubbery polymer preferably blended with PC has a glass transition temperature (Tg) of-
The temperature is preferably 30 ° C or lower, and if it exceeds -30 ° C, the impact resistance tends to decrease. Examples of such rubbery polymers include diene rubbers such as polybutadiene, poly (styrene-butadiene) and poly (acrylonitrile-butadiene), and saturated rubbers obtained by hydrogenating the diene rubbers, isoprene rubbers, chloroprene rubbers, and the like. Acrylic rubber such as polybutyl acrylate and ethylene-
Cross-linked rubber or non-cross-linked rubber such as propylene copolymer rubber, ethylene-propylene-diene monomer terpolymer rubber (EPDM), ethylene-octene copolymer rubber,
In addition, a thermoplastic elastomer containing the rubber component can be used. Among the above thermoplastic elastomers, a polystyrene-based thermoplastic elastomer is particularly preferable, and a block copolymer comprising an aromatic vinyl unit and a conjugated diene unit, or a block copolymer in which the conjugated diene unit is partially hydrogenated or epoxy-modified. It is a polymer or the like. By blending the thermoplastic elastomer with PC, the problem that the impact strength is reduced when PC is formed into a thick molded body is solved. At that time, by further blending the styrene copolymer as a compatibilizer, excellent impact strength is exhibited.

The aromatic vinyl monomer constituting the block copolymer is, for example, styrene, α-methylstyrene, paramethylstyrene, p-chlorostyrene, p-bromostyrene, 2,4,5-tribromobenzene. Styrene is the most preferable, and styrene is most preferable. However, other aromatic vinyl monomers described above may be copolymerized mainly with styrene. Further, the conjugated diene monomer constituting the block copolymer,
Examples thereof include 1,3-butadiene and isoprene. In the block structure of the block copolymer, a polymer block composed of an aromatic vinyl unit is represented by S, and a polymer block composed of a conjugated diene and / or a partially hydrogenated unit thereof is represented by B. In case, SB, S
(BS) n, (where n is an integer of 1 to 3), S (BS
B) n (where n is an integer of 1 to 2) linear block copolymer or (SB) nX (where n is an integer of 3 to 6).
X is a residue of a coupling agent such as silicon tetrachloride, tin tetrachloride, and a polyepoxy compound. ), And is preferably a star-shaped (star) block copolymer having a portion B as a bonding center. Above all, type 2 of SB, type 3 of SBS, SBSB
Type 4 linear-block copolymers are preferred.

(B) in the present invention is a phosphorus, nitrogen, sulfur or inorganic flame retardant. The phosphorus-based flame retardant comprises an organic phosphorus-based, red phosphorus-based, and inorganic phosphorus-based flame retardant. Examples of the organic phosphorus flame retardant of the phosphorus flame retardant (B) in the present invention include phosphine, phosphine oxide, biphosphine, phosphonium salt, phosphinate, phosphate ester, phosphite ester and the like. More specifically,
Triphenyl phosphate, methyl neopentyl phosphite, pentaerythritol diethyl diphosphite, methyl neopentyl phosphonate, phenyl neopentyl phosphate, pentaerythritol diphenyl diphosphate, dicyclopentyl hypophosphate, dineopentyl hypo Phosphite, phenyl pyrocatechol phosphite, ethyl pyrocatechol phosphate, dipyrocatechol hypopositive phosphate. Here, as the organic phosphorus compound, an aromatic phosphate ester monomer and an aromatic phosphate ester condensate are particularly preferred.

In the above (B), red phosphorus, which is one of the phosphorus-based flame retardants, is not limited to ordinary red phosphorus, and its surface is previously selected from aluminum hydroxide, magnesium hydroxide, zinc hydroxide and titanium hydroxide. Coated with a metal hydroxide coating, coated with a coating composed of a metal hydroxide selected from aluminum hydroxide, magnesium hydroxide, zinc hydroxide, and titanium hydroxide, and a thermosetting resin , Aluminum hydroxide, magnesium hydroxide,
Examples thereof include those obtained by double-coating a thermosetting resin film on a metal hydroxide film selected from zinc hydroxide and titanium hydroxide. In the above (B), one of the inorganic phosphorus-based flame retardants of the phosphorus-based flame retardant is ammonium polyphosphate or a composite flame retardant of the same with a nitrogen compound, or a phosphazene-based compound, particularly a phosphorus atom having an aromatic group. Is preferably a compound having a structure in which a nitrogen atom and a nitrogen atom are connected by a double bond, such as cyclic phosphazene or linear phosphazene. Among the phosphazenes, from the viewpoint of compatibility with the aromatic polycarbonate, the phosphazene contains an aromatic group such as a phenyl group, a cresyl group, a xylyl group, and a bisphenyl group as a substituent. Specifically, phenoxypropoxyphosphazene, diphenoxyphosphazene, phenoxyaminophosphazene,
Phenoxyfluoroalkylphosphazene and the like,
These phosphazene compounds are produced by replacing chlorophosphazene with alcohols or phenols.

The nitrogen-based flame retardant (B) is typically a compound containing a triazine skeleton, and is a component for further improving the flame retardancy as a flame retardant auxiliary of a phosphorus-based flame retardant. Specific examples thereof include melamine, melam, melem, melon (product of deammonification of three to three molecules of melem at 600 ° C. or higher), melamine cyanurate
G, melamine phosphate, succinoguanamine, adipoguanamine, methylglutalogamine, melamine resin, B
T resin can be used, but melamine cyanurate is particularly preferable from the viewpoint of low volatility. Examples of the sulfur-based flame retardant (B) include metal salts of organic sulfonates such as potassium trichlorobenzenesulfonate, potassium perfluorobutanesulfonate, potassium diphenylsulfon-3-sulfonate, and metal salts of aromatic sulfonimides. Metal ring sulfonate, metal sulfate, metal phosphate, metal borate, or ammonium salt, phosphonium salt of the above acid, etc. on the aromatic ring of an aromatic group-containing polymer such as a styrene polymer or polyphenylene ether. Is a sulfur-based flame retardant such as an alkali metal salt of polystyrene sulfonic acid. Such a sulfur-based flame retardant promotes a decarboxylation reaction at the time of combustion, particularly when polycarbonate is used as a polymer, to improve flame retardancy. Further, in the case of the alkali metal polystyrene sulfonate, the metal sulfonate itself becomes a cross-linking point during combustion and greatly contributes to the formation of a carbonized film.

The inorganic flame retardant (B) includes silica, aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, basic magnesium carbonate, zirconium hydroxide, Hydrate of inorganic metal compounds such as hydrate of tin oxide, aluminum oxide, iron oxide, titanium oxide, manganese oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide,
Metal oxides such as chromium oxide, tin oxide, antimony oxide, nickel oxide, copper oxide, and tungsten oxide, aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, tin, and antimony Metal powder, and zinc borate, etc.
Examples include zinc metaborate, barium metaborate, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate and the like. These may be used alone or in combination of two or more. Among them, those selected from the group consisting of magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, and hydrotalcite have particularly good flame retardant effects and are economically advantageous. When a higher degree of flame retardancy is required in the present invention, a flame retardant auxiliary (C) selected from a fibrous flame retardant and a char forming agent can be blended as necessary.

The fibrous flame retardant (C) is a flame retardant used to prevent dripping of fire, and becomes fibrous at the time of addition or processing. Specific examples thereof include aramid fiber, polyacrylonitrile fiber, and fluororesin. The aramid fiber has an average diameter of 1 to 5
It is preferable that the average fiber length is 0.1 to 10 mm at 00 μm, and it is produced by dissolving isophthalamide or polyparaphenylene terephthalamide in a polar amide solvent or sulfuric acid and spinning the solution by a wet or dry method. Can be. The polyacrylonitrile fiber as the fibrous flame retardant preferably has an average diameter of 1 to 500 μm and an average fiber length of 0.1 to 10 mm, and dissolves the polymer in a solvent such as dimethylformamide, 400 ° C.
It is produced by a dry spinning method in which the polymer is dissolved in a solvent such as nitric acid, or a dry spinning method in which the polymer is dissolved in a solvent such as nitric acid. The fluororesin as the fibrous flame retardant is a resin containing a fluorine atom in the resin. Specific examples thereof include polymonofluoroethylene, polydifluoroethylene, polytrifluoroethylene, polytetrafluoroethylene, and a tetrafluoroethylene / hexafluoropropylene copolymer. If necessary, the fluorine-containing monomer may be used in combination with a copolymerizable monomer.

The char-forming agent as (C) is preferably a novolak resin or the like, particularly a phenol novolak resin obtained by condensing phenols and aldehydes in the presence of an acid catalyst such as sulfuric acid or hydrochloric acid. preferable. In the present invention, the added amount of (B) or (C) is (A)
The amount is preferably 0.001 to 100 parts by weight, more preferably 1 to 50 parts by weight, most preferably 3 to 20 parts by weight, and most preferably 5 to 15 parts by weight with respect to 100 parts by weight. In the present invention, if necessary, aliphatic hydrocarbons, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher aliphatic alcohols, metal soaps, organosiloxane waxes, polyolefin waxes, polycaprolactone, or one or more selected from Two or more types of release agents or processing aids (D) as flow improvers can be blended. The amount of (D) is preferably 0.01 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, and most preferably 1 to 5 parts by weight, per 100 parts by weight of (A). . In the present invention, when light resistance is required, as necessary, an ultraviolet absorber, a hindered amine light stabilizer, an antioxidant, an active species trapping agent, a light shielding agent, a metal deactivator, or a quencher. One or more lightfastness improvers (E) selected from agents can be blended. (E)
Is preferably 0.1 to 100 parts by weight of (A).
05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, and most preferably 1 to 5 parts by weight.

The flame-retardant resin molded article of the present invention is produced by lowering the shear melt viscosity by 10% or more by dissolving carbon dioxide with respect to the shear melt viscosity when carbon dioxide is not dissolved in the resin composition. I do. Specifically, as one of the production methods, the molten resin composition in which the melt viscosity is reduced by dissolving the carbon dioxide is previously filled with carbon dioxide at a pressure higher than a pressure at which foaming does not occur at the flow front of the molten resin in the mold cavity. This is a method of injecting into a mold cavity in a pressurized state. In the present invention, it is preferable to produce a resin composition in advance before producing a molded article, and subsequently introduce carbon dioxide to produce a molded article by the above-mentioned processing method. As a method of preparing the resin composition in advance, for example, a method of directly mixing (A) and (B) and melt-kneading with an extruder, or a method of first melting (A) and then (B)
And melt kneading with the same extruder, or a method of manufacturing a master batch containing (B) and then kneading the master batch and (A). In the present invention, the following two methods are preferred as methods for dissolving carbon dioxide in the PC-based resin composition. one,
A method in which a granular or powdery resin is placed in a carbon dioxide atmosphere in advance to absorb carbon dioxide, and then supplied to a molding machine.
The amount of carbon dioxide absorbed depends on the pressure, ambient temperature, and time of absorption. In this method, a part of carbon dioxide in the resin is volatilized as the resin is heated during plasticization, so that the amount of carbon dioxide in the molten resin is smaller than the amount previously absorbed. For this reason, it is desirable that the supply path of the resin such as the hopper of the molding machine is also in a carbon dioxide atmosphere. Another method is to plasticize the resin in the cylinder of the molding machine, or to dissolve carbon dioxide in the plasticized resin. Inject carbon dioxide from the cylinder into the plasticized resin. When injecting carbon dioxide from an intermediate portion of a screw or a cylinder, it is preferable to increase the depth of the screw groove near the injection portion to lower the resin pressure. In order to uniformly dissolve and disperse carbon dioxide in the resin after injecting carbon dioxide, it is preferable to attach a mixing mechanism such as a dalmage or a kneading pin to the screw or to provide a static mixer in the resin flow path. As an injection molding machine, either an in-line screw system or a screw prepra system can be used.However, the screw prepra system is particularly easy because the screw design of the extruder part for plasticizing the resin and the injection position of carbon dioxide are easy to change. preferable.

The carbon dioxide in the PC-based resin composition is gradually released into the air if the molded article is left in the air after the resin composition has solidified. No bubbles are generated in the molded article due to the radiation, and the performance of the molded article after the radiation is essentially the same as that of the thermoplastic resin. In the present invention, the mold cavity is previously pressurized with gas to a pressure higher than the pressure at which foaming does not occur at the flow front of the molten resin during resin filling, and injection molding is performed. The gas pressure to be filled in the cavity should be the minimum pressure that does not generate a foaming pattern on the surface of the molded product.The amount of gas used in one process should be minimized, and the structure of the mold cavity seal and gas supply device should be reduced. For simplicity, the gas pressure is preferably low. If the gas pressure exceeds 15 MPa, problems tend to occur such that the force for opening the mold cannot be ignored or the sealing of the mold cavity becomes difficult. As the gas to be injected into the mold cavity, simple substances or mixtures of various gases inert to the resin, such as air and nitrogen, can be used. However, carbon dioxide, hydrocarbons and their gases having high solubility in the thermoplastic resin can be used. Hydrogen partially substituted by fluorine is preferable, and carbon dioxide is particularly preferable because it has a high effect of improving the transferability of a mold surface state to a molded article. When amorphous resin is used as the resin and the cavity is pressurized with carbon dioxide, Japanese Patent Application No. Hei 9-236
As described in Japanese Patent Application No. 763 and Japanese Patent Application No. 10-46903, higher transfer pressure is obtained by increasing the gas pressure in the cavity. It is desirable to increase the gas pressure as much as possible according to the mold clamping force of the machine and the sealing performance of the mold. The higher the carbon dioxide content of the gas in the mold cavity, the better,
Particularly preferred is 80% by volume or more. Gases at various temperatures can be used. Heated gas as well as gas at ambient temperature can be used favorably. In the case of a heated gas, a mixed gas of a liquid vapor and a carbon dioxide that easily dissolves the carbon dioxide can be used favorably.

In the present invention, carbon dioxide is contained in an amount of 0.2 to 3% by weight.
A molding method of sequentially or simultaneously injecting the dissolved PC resin composition and another thermoplastic resin into the mold cavity can also be used favorably. P containing 0.2 to 3% by weight of carbon dioxide
The injection molding method of injecting the C-based resin composition and then injecting another thermoplastic resin containing no carbon dioxide to fill the mold cavity can be used particularly well. Other thermoplastic resin and PC-based resin composition, if the same type of thermoplastic resin has a different carbon dioxide content, if the molecular weight is different, if it is another type of thermoplastic resin, further if the carbon dioxide content is different, etc. Yes, this combination can be appropriately selected. P
By blending carbon dioxide into the C-based resin composition, the melt viscosity is reduced, and a composite injection-molded article comprising a uniform surface layer of another thermoplastic resin and the inner core of the PC-based resin composition is obtained.
By using a thermoplastic resin excellent in heat resistance, chemical resistance, physical properties, etc. for other thermoplastic resins, the surface layer can be coated with other thermoplastic resins and the performance of molded products can be improved .

[0024]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention. In addition, the measurement in an Example and a comparative example was performed using the following method or a measuring device. (1) The amount of carbon dioxide in the molten resin It is difficult to directly measure the amount of carbon dioxide in the molten resin injected into the mold cavity. Therefore, the weight of the molded product immediately after the injection molding using the resin containing carbon dioxide. And the difference between the weights of the molded articles, which were left in a hot air dryer about 30 ° C. lower than the glass transition temperature for 24 hours or more, and the amount of carbon dioxide contained in the molded articles was diffused and became constant. Was the amount of carbon dioxide in the molten resin injected into the mold cavity. (2) Shear Melt Viscosity For resins containing no carbon dioxide, use a capillary rheometer manufactured by ROSAND Co.
The shear melt viscosity (Pa · s) was determined under the conditions of ° C. and a shear rate of 1000 sec ⁻¹ , which was used as a measure of fluidity. Test conditions: Long die length 16 mm Long die diameter 1 mm Short die length 0.25 mm Short die diameter 1 mm Die entry angle 180 deg For resin containing carbon dioxide, the hole of the injection molding machine nozzle is 1 mm in diameter and 5 mm in length, and the shear rate is Was performed for about 1000 sec ^−1, and the resin pressure in the cylinder required for the free purge was compared with a resin containing no carbon dioxide to determine a shear melt viscosity.

(3) Flame retardancy VB (Vertical Bur) conforming to UL-94
The self-extinguishing property was evaluated by the ning method. (1
/ 8 inch thickness test piece) (4) Izod impact strength Measured by a method based on ASTM-D256. (23
(° C, 1/4 inch thickness test piece with V notch) (5) Extrusion stability (quality stability) The resin composition was continuously melt-extruded for 10 hours using a melt extruder, and was obtained every hour. The Izod impact strength of the composition was measured, and the maximum rate of change to the average strength (%)
Continuous productivity (quality stability) was evaluated from (Izod change rate (%) in Tables 1 to 5). The following components were used for each component used in Examples and Comparative Examples. (A) Non-halogen flame retardant (a) Metal salt of organic sulfonate UCB Nippon Co., Ltd., potassium diphenylsulfon-3-sulfonate (referred to as S1) (b) 1,3-phenylene bis (diphenyl phosphate) Daihachi Chemical Industry Co., Ltd., aromatic condensed phosphate ester derived from resorcinol [trade name: CR733S (referred to as P1)] (c) Bisphenol A bis (diphenyl phosphate) Daihachi Chemical Industry Co., Ltd., [trade name: CR741 (P2 and (D) 1,3-phenylene bis (dixylyl phosphate) manufactured by Daihachi Chemical Industry Co., Ltd., [trade name PX200 (referred to as P3)] (e) Red phosphorus manufactured by Rin Kagaku Kogyo Co., Ltd., [products] Name Nova Excel (P4
(F) Ammonium polyphosphate, manufactured by Chisso Corporation, [trade name (named P5)] (g) Phenoxyphosphazene Phenoxyphosphazene (P) synthesized by a known method
(H) Magnesium hydroxide, manufactured by Kyowa Chemical Industry Co., Ltd., [trade name: Kusuma (referred to as MOH)] (i) Melamine cyanurate manufactured by Nissan Chemical Industries, Ltd., [trade name: MC610 (referred to as M1) )] (B) Flame retardant aid Polytetrafluoroethylene manufactured by Daikin Industries, Ltd. (referred to as PTFE)

(C) Polymer (a) Aromatic polycarbonate [Bisphenol A type, trade name, Caliber 13 (referred to as PC)] manufactured by Sumitomo Dow, Ltd. (b) Rubber-modified polystyrene (HIPS) manufactured by Asahi Chemical Industry Co., Ltd. Polybutadiene / polystyrene (10/90: weight ratio) Trade name Stylon (HIPS
(C) ABS resin (ABS) [Acrylonitrile / Polybutadiene / Styrene (24/20/56: weight ratio) (trade name) Styrac ABS (referred to as ABS) manufactured by Asahi Kasei Corporation] (d) Styrene Ethylene butylene-styrene copolymer (SEBS) Asahi Kasei Kogyo Co., Ltd. [trade name Tuftec (referred to as SEBS)] (e) Styrene butadiene copolymer (SB) Asahi Kasei Kogyo Co., Ltd. [trade name Tufprene ( SB)) (f) Epoxy-modified styrene-butadiene copolymer (ES
B) Daicel Chemical Industries, Ltd. [brand name Epo Friend (E
SB)) (g) Syndiotactic styrene-based polymer Syndiotactic polystyrene having a melting point of 270 ° C and a weight average molecular weight of 320,000 (referred to as SPS) (h) Polyphenylene ether (PPE) manufactured by Asahi Chemical Industry Co., Ltd. [Trade name Zylon (referred to as PPE)] (i) Polypropylene (PP) manufactured by Nippon Polychem Co., Ltd. (referred to as PP) (j) Ethylene-octene copolymer (EO) Dupont Dow elastomer [trade name Engage (E
O)) (k) Acrylonitrile-styrene copolymer (AS) A) AS (AS-1) having a copolymer composition distribution It was produced by the method described in WO95 / 35346.・ Acrylonitrile / styrene = 6/94 ・ Average SP value is 10.75 ・ Distribution of the ratio of monomer components of the copolymer: acrylonitrile unit is 0 to 12% by weight The maximum SP value of the copolymer molecule is 11.0 Minimum SP value is 10.5 ΔSP value is 0.5 (l) EO-PP crosslinked product (TPV) Twin screw extruder using organic peroxide and divinylbenzene in EO / PP = 50/50 (weight ratio) A thermoplastic polypropylene dynamically crosslinked was used. (Referred to as TPV)

(Molding machine) SG is manufactured by Sumitomo Heavy Industries, Ltd.
125M-HP was used, and the screw was a two-stage vent type with L / P24 and a diameter of 32 mm. The vent was pressurized with carbon dioxide to dissolve carbon dioxide in the molten resin. As the nozzle, a needle type shut-off type nozzle was used. (Mold) As the mold, a molded product having a square shape and a rectangular shape were used. The product part of the square plate mold is 100 for each length and width.
mm and a thickness of 2 mm. Regarding the structure of a square plate mold, the cavity surface is mirror-finished,
mm direct gate, sprue length is 58m
m, the diameter of the nozzle touch portion was 3.5 mm. Depth of 0.0 for gas supply and release around the mold cavity
A 5 mm vent slit and vent, and a hole from the vent to the outside of the mold are provided and connected to the counter gas supply device.
A ring was provided to make the cavity airtight. (Counter gas supply device) A cylinder filled with liquefied carbon dioxide was kept at 35 ° C and used as a gas supply source. The gas passes through a heater from a cylinder, is adjusted to a predetermined pressure by a pressure reducing valve, and is then stored in a gas reservoir having an internal capacity of 1000 cm3, which is kept at about 40 ° C. Gas supply to the mold cavity is performed by opening the supply solenoid valve downstream of the gas reservoir and simultaneously closing the release solenoid valve, and the gas reservoir and the cavity are connected during resin filling. At the same time as the resin filling is completed, the supply electromagnetic valve is closed and the release electromagnetic valve is opened to release the gas out of the mold.

(Example 1, Comparative Example 1) The compositions (parts by weight) shown in Table 1 were mixed with a Henschel mixer, and subsequently, a twin-screw extruder (40 mm) having an inlet at the center of the barrel was used.
φ, L / D = 47) and 1 at 240 ° C.
Continuous melt extrusion was performed for 0 hours. As the screw, a double screw having a kneading portion before and after the injection port was used. A molded article was prepared from the composition thus obtained by injection molding at a cylinder set temperature of 250 ° C. and a mold temperature of 80 ° C. under the following conditions, and was evaluated. That is, the resin as the above composition was dried in a hot air drier at 120 ° C. for 5 hours, carbon dioxide pressure at the vent portion was 5 MPa, and screw rotation speed was 150 r.
pm plasticized. Then, counter pressure molding using carbon dioxide was performed using a square plate mold having a mold surface temperature of 80 ° C., and the resin pressure in the cylinder of the molding machine required for filling the resin was measured. Resin filling time 0.5 seconds, counter pressure 1
In the case of MPa, the required filling pressure was 211 MPa.
After filling the resin, the pressure was maintained at a cylinder internal pressure of 190 MPa for 5 seconds, and after cooling for 20 seconds, the molded product was taken out. The molded product was a transparent molded product having no foaming pattern on the surface. The amount of carbon dioxide in the plasticized molten resin determined from the weight loss of the molded article after the injection molding was 0.5% by weight. (Example 1) On the other hand, without supplying carbon dioxide to the vent portion, the resin pressure in the cylinder of the molding machine required for filling the resin was measured in the same manner as in Example 1. Without counter pressure, required filling pressure is 2
It was 35 MPa. (Comparative Example 1) The molten resin of Example 1 and Comparative Example 1 was subjected to free purge using a molding machine nozzle for measuring the shear melt viscosity, and the amount of reduction in the shear melt viscosity due to carbon dioxide was determined. there were. Table 1 shows the results of the above details.

(Examples 2 to 3 Comparative Example 2) Except that the composition ratio was changed to that shown in Table 2 and the rate of decrease in melt viscosity was changed to 10% and 30% by controlling the amount of carbon dioxide introduced.
The same experiment as in Example 1 and Comparative Example 1 was repeated. The results are shown in Table 2. (Examples 4 to 39) By changing the composition ratios shown in Tables 3 and 5, and controlling the amount of carbon dioxide introduced, the rate of decrease in melt viscosity was 1
The same experiment as in Example 1 and Comparative Example 1 was repeated except that the value was changed to 5%. The results are shown in Tables 3 to 5.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

[Table 5]

[0035]

According to the present invention, according to a specific processing method,
A resin composition comprising an aromatic polycarbonate and a specific non-halogen flame retardant provides a flame-retardant resin molded article having high flame retardancy, impact resistance and quality stability. The molded article of the present invention includes a VTR, a distribution board, a television, an audio player, a condenser, a household outlet, a radio cassette, a video cassette, a video disk player, an air conditioner, a humidifier, and an electric hot air machine. Home appliance housing, chassis or parts, CD-ROM mainframe
(Mechanical chassis), printer, fax, PP
C, CRT, word processor, electronic cash register, office computer system, floppy (registered trademark)
OA equipment housing such as disk drive, keyboard, type, ECR, calculator, toner cartridge, telephone, chassis or parts, connector, coil bobbin, switch, relay, relay socket, LED, variable condenser ,
AC adapter, FBT high pressure bobbin, FBT case,
IFT coil bobbin, jack, volume shaft,
Electronic and electrical materials such as motor parts, instrument panels, radiator grills, clusters, speaker grills, louvers, console boxes, defroster garnishes, -Suitable for automobile materials such as ornaments, fuse boxes, relay cases, connector shift tapes, etc., and play a large role in these industries.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // B29K 69:00 B29K 69:00 F term (reference) 4F071 AA12X AA15X AA20 AA21X AA22X AA34X AA50 AA51 AA77 AA88 AB17 AC12 AC15 AE07 AF23 AF47 AH12 BB05 4F206 AA28 AB05 JA07 JM04 JN14 JN27 JQ81 4J002 AA002 BN142 BN152 CC183 CG011 DA056 DE017 DE076 DE096 DE126 DE146 DE236 DE246 DE266 DE286 DH056 DJ006 DJ016 DK006 EU186 EW066 136 006 EW 136 136

Claims (2)

[Claims] 1. A resin composition comprising an aromatic polycarbonate or a resin mainly composed of an aromatic polycarbonate, and one or more non-halogen flame retardants selected from phosphorus, nitrogen, sulfur and inorganic flame retardants. A flame-retardant resin molded article obtained by molding by lowering the melt viscosity by dissolving 2. The molten resin composition in which the melt viscosity is reduced by dissolving carbon dioxide is previously pressurized in the mold cavity with carbon dioxide at a pressure higher than a pressure at which foaming does not occur at the flow front of the molten resin. 2. The flame-retardant resin injection-molded article according to claim 1, wherein the molded article is obtained by injecting into a mold cavity.