JPH11269364A - Flame retardant polyester resin composition and molded article comprising the same and used for household electric appliance and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition maintaining excellent heat resistance, mechanical characteristics and flame retandancy and giving molded articles having good surface appearances, especially good color tones and good luster, and to obtain a molded article comprising the same and used for a household electric appliance. SOLUTION: This flame retardant polyester resin composition comprises 100 pts.wt. of an aromatic polyester, 3-60 pts.wt. of a brominated polycarbonate, and 0.01-4 pts.wt. of a phosphorous compound, wherein the phosphorous compound comprises one or more kinds of compounds selected from the group consisting of phosphate esters and phosphite esters and one or more kinds of compounds selected from the group consisting of the metal salts of phosphoric acid and phosphorous acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a molding resin having a long molding cycle, a high melting resin temperature, high thermal stability of the molten resin, excellent surface appearance, color tone and glossiness of the molded product, and rigidity and heat resistance. The present invention relates to a flame-retardant polyester resin composition having excellent heat resistance and a molded article for home electric appliances obtained by molding the composition.

[0002]

2. Description of the Related Art In the field of electric products such as home electric appliances, it is necessary to comply with the Product Liability Law (PL Law), and there is a demand for improvement in product safety.

[0003] As a part of this, there is a trend to make plastic parts flame-retardant. Such appliances include irons,
There are dryers, ovens, microwave ovens, etc., and engineering plastics are used for heat-resistant applications.

[0004] Aromatic polyester resins represented by polyethylene terephthalate and polybutylene terephthalate generally have various excellent properties such as oxidation resistance and solvent resistance, and thus have good physical and mechanical properties by injection molding. Suitable for obtaining molded articles.

[0005]

Further, in the field of electrical products in which molded products formed from these aromatic polyester resins are used for home electric appliances and the like, it is difficult to maintain heat resistance and mechanical properties while maintaining the heat resistance and mechanical properties. It is necessary to satisfy flammability, and the appearance of the product must be glossy for use as a home appliance.

When molding these molded products, the temperature of the molten resin is sometimes raised in order to lower the viscosity of the molten resin to facilitate molding. In the conventional technique of stabilizing the melting heat, various techniques have been developed with attention paid to the maintenance of mechanical properties. Therefore, a sufficient stabilizing effect was obtained at a normal molten resin temperature and a molding cycle.

However, in applications where the commercial value is impaired by fading when exposed to sunlight or fluorescent lamps, such as home appliances, for example, brominated polycarbonate flame retardants having good light discoloration resistance are preferably used. However, yellowing due to transesterification between the polyester resin and the brominated polycarbonate may occur during molding at a high temperature or during stagnation caused by a prolonged molding cycle. The degree was limited.

Further, when a flame retardant is added to obtain the flame retardancy of the molded article, the appearance of the molded article, especially the surface gloss, is deteriorated. The transferability to the mold is deteriorated, and the surface appearance of the molded product is further deteriorated. If the surface appearance of the molded article is deteriorated in this way, the value of the product as a home appliance is undesirably reduced.

The present invention has been made to solve the above-mentioned problems, and has excellent heat resistance, mechanical properties, and flame retardancy while maintaining the surface appearance of a molded product when molded, particularly color tone and gloss. It is an object of the present invention to obtain a resin composition having a good quality and a molded article for home electric appliances comprising the same.

Further, the present invention employs molding conditions of a long molding cycle and a high molten resin temperature, and uses a flame-retardant polyester resin composition having a stable molten resin viscosity under these conditions to obtain a surface appearance, particularly a color tone and gloss. It is an object to obtain a good molded product for home appliances.

[0011]

That is, the present invention comprises 3 to 60 parts by weight of a brominated polycarbonate and 0.01 to 4 parts by weight of a phosphorus compound per 100 parts by weight of an aromatic polyester. A flame-retardant polyester resin composition which is at least one selected from the group consisting of phosphoric acid ester and phosphorous acid ester, and the group consisting of phosphoric acid and phosphorous acid metal salt.

The aromatic polyester used in the present invention comprises terephthalic acid as a dicarboxylic acid component and alkylene glycol having 2 to 10 carbon atoms as a glycol component. As the alkylene glycol, ethylene glycol, tetramethylene glycol or propylene glycol is preferable.

The aromatic polyester may be one in which a part of the terephthalic acid component and / or the ethylene glycol component is replaced by a copolymerization component.

As the copolymerization component, dicarboxylic acid components such as isophthalic acid and phthalic acid; halogen-substituted phthalic acid such as tetrabromophthalic acid and tetrabromoterephthalic acid; and alkyl-substituted phthalic acid such as methyl isophthalic acid; 2,6-naphthalene dicarboxylic acid,
Naphthalene dicarboxylic acids such as 2,7-naphthalene dicarboxylic acid and 1,5-naphthalene dicarboxylic acid;
Diphenyldicarboxylic acids such as 4'-diphenyldicarboxylic acid, 3,4'-diphenyldicarboxylic acid;
Aromatic dicarboxylic acids such as 4'-diphenoxyethane dicarboxylic acid; and aliphatic or alicyclic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, decadicarboxylic acid, and cyclohexanedicarboxylic acid. Examples of the glycol component include aliphatic or alicyclic diols such as trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, and 1,4-cyclohexanedimethanol; dihydroxybenzenes such as hydroquinone and resorcin; Bisphenols such as 2,2'-bis (hydroxyphenyl) propane and 2,2'-bis (4-hydroxyphenyl) -sulfone; ether diols obtained from bisphenols and glycols such as ethylene glycol; Such aromatic diol; can be exemplified such as polyoxyalkylene glycols such as polyoxytetramethylene glycol. Furthermore, ε
-Oxycarboxylic acids such as hydroxybenzoic acid and hydroxyethoxybenzoic acid can be exemplified.

These copolymer components can be used alone or in combination of two or more, and their ratio is determined by total dicarboxylic acid (half of oxycarboxylic acid is calculated as carboxylic acid).
It is preferably at most 20 mol%, more preferably at most 10 mol%, per mol.

Further, the above-mentioned aromatic polyester may be a branched component, for example, a trifunctional acid such as tricarballylic acid, trimellicinic acid, trimellitic acid, or a tetrafunctional acid such as pyromellitic acid, or glycerin, triglycerin, or trifunctional acid. 1.0 mol% or less, preferably 0.5 mol%, of a trifunctional or tetrafunctional ester-forming alcohol such as methylolpropane or pentaerythritol.
Below, more preferably 0.3 mol% or less may be copolymerized. These aromatic polyester resins can be used alone or in combination of two or more.

As the aromatic polyester, polybutylene terephthalate and polyethylene terephthalate are particularly preferred.

[Brominated Polycarbonate] As the brominated polycarbonate used in the present invention, a brominated bisphenol A, particularly a polycarbonate obtained from tetrabromobisphenol A is preferable. Its terminal structure is 4
Examples thereof include a -t-butylphenyl group and a 2,4,6-tribromophenyl group. In order to improve the appearance gloss of the molded article of the present invention, particularly, the terminal group structure has a 2,2 group.
Those having a 4,6-tribromophenyl group are preferred.

These brominated polycarbonates preferably have an average carbonate repeating unit of 3 to 7, and have a melting point of 185 ° C. to 25 ° C.
Preferably it is 0 ° C. Polycarbonates having an average carbonate repeating unit of less than 3 also have a lower melting point,
In particular, when used together with a polyester, the molecular weight of the polyester is reduced during melting, which is not preferable.
On the other hand, when the number of repeating units exceeds 7, the melt viscosity of the polycarbonate becomes high, which causes poor dispersion in the molded product, which is not preferable because the appearance of the molded product, particularly the glossiness, is lowered. Melting point of brominated polycarbonate is 185 ° C to 2
A temperature of 50 ° C. is particularly preferable from the viewpoint of gloss of the appearance of the molded article.

The brominated polycarbonate obtained from the above brominated bisphenol A can be obtained, for example, by a usual method of reacting a brominated bisphenol with phosgene. Examples of the terminal blocking agent include an aromatic monohydroxy compound which may be substituted with a halogen or an organic group.

The amount of the brominated polycarbonate used in the present invention is 3 per 100 parts by weight of the aromatic polyester.
６０60 parts by weight, preferably 10-50 parts by weight. When the blending amount of the inorganic filler in the whole composition is increased or when a flame retardant aid described below is used, the blending amount of the flame retardant can be reduced, but even in that case, the object of the present invention is achieved. Requires at least 3 parts by weight, and if less than 3 parts by weight, the resulting composition has insufficient flame retardancy. More specifically, if the amount is less than 3 parts by weight, the thickness cannot be reached to the vertical combustion standard UL94V-0 with a thickness of 1.6 mm. On the other hand, when the amount of the brominated polycarbonate exceeds 60 parts by weight, the thermal stability at the time of melting is reduced, and the surface appearance of the molded product, particularly, the gloss is reduced.

[Phosphorus Compound] The phosphorus compound used in the present invention includes phosphoric acid, phosphoric ester, phosphite,
It is a phosphorus compound selected from the group consisting of metal salts of phosphoric acid and phosphorous acid. More specifically, as the phosphoric acid ester and the phosphite, trimethyl phosphate, methyl diethyl phosphate, triethyl phosphate, isopropyl phosphate, tributyl phosphate, triphenyl phosphate, tribenzyl phosphate, tribenzyl phosphate Phosphoric acid esters such as cyclohexyl; phosphites such as trimethyl phosphite, triethyl phosphite, tributyl phosphite, tri (δ-hydroxybutyl) phosphite, triphenyl phosphite; phosphoric acid and phosphorus phosphite Examples of the metal salt of an acid include monosodium phosphate, disodium phosphate, and trisodium phosphate.
Metal salts of phosphoric acid, such as potassium, monolithium phosphate, aluminum phosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate, and hydrates thereof, and the corresponding metal phosphite salts.

In the present invention, the phosphorus compound is at least one selected from the group consisting of phosphoric acid esters and phosphites and the group consisting of phosphoric acid and metal salts of phosphorous acid. It is necessary to be. Even if only one or more phosphorus compounds selected from any one of the above groups are blended as the phosphorus compound, the molten resin temperature is 260 ° C. or more, and when molded under molding conditions of a molding cycle of 60 seconds or more, The effect of stabilization cannot be obtained, and it is impossible to simultaneously obtain both the effect of stabilizing the appearance of the molded article and the effect of suppressing discoloration.

The phosphorus compound is an aromatic polyester resin 10
0.01 to 4 parts by weight per 0 parts by weight. 0.0
If the amount is less than 1 part by weight, the effect of stabilizing the melting and the effect of suppressing discoloration are small, and the effect of stabilizing the appearance of the molded product is also small, which is not preferable. Further, even if added in an amount exceeding 4 parts by weight, a further stabilizing effect upon melting, a discoloration suppressing effect, and a stabilizing effect on the appearance of a molded product cannot be obtained.

The phosphorus compound selected from the group consisting of phosphoric acid esters and phosphites is preferably from 20% by weight to 80% by weight per 100% by weight of the total weight of the phosphorus compound in the present invention. The phosphorus compound selected from the group consisting of metal salts of acids is preferably 20 to 80% by weight per 100% by weight of the total weight of the phosphorus compound in the present invention. Within this range, both the effect of stabilizing the appearance of the molded article and the effect of suppressing discoloration can be simultaneously obtained, which is preferable.

[Fluorine Compound] The resin composition of the present invention preferably contains a fluorine compound. Examples of the fluorine compound include a fluorine-substituted polyolefin resin, and polytetrafluoroethylene is particularly preferable. The amount of the fluorine-based compound is 0 to 4 parts by weight, preferably 0.2 to 2 parts by weight, based on 100 parts by weight of the aromatic polyester resin. Even if the amount exceeds 4 parts by weight, the effect of further improving the appearance of the molded article cannot be obtained due to the effect of reducing the flame retardant. However, if it is added in an amount of 0.2 parts by weight or more, the flame retardancy is improved and the appearance of the molded article is improved. Is preferred because of its high effect.

[Antimony Compound] In the present invention, an antimony compound can be blended as a flame retardant aid for the purpose of promoting the flame retardant effect. Examples of suitable antimony compounds include Sb ₂ O ₃ and / or _x Na ₂ O.Sb _{2
O 5 · yH 2 O (x} = 0~1, y = 0~4) and the like.

When an antimony compound is contained, its particle size is preferably from 0.02 to 5 μm. Also, if desired
Those surface-treated with an epoxy compound, a silane compound, an isocyanate compound, a titanate compound, or the like can be used. The amount of the antimony compound is from 0 to 40 parts by weight based on 100 parts by weight of the brominated polycarbonate. However, in order to effectively impart flame retardancy, the amount of the antimony compound is from 20 to 70 parts by weight based on 100 parts by weight of the brominated polycarbonate. It is preferable to mix them. If the added amount exceeds 40 parts by weight with respect to 100 parts by weight of the brominated polycarbonate, the decomposition of the resin and the compounding agent is promoted, and the properties of the molded article may be undesirably reduced.

[Other Flame Retardants] In the present invention, other flame retardants can be used in combination for the purpose of improving flame retardancy and mechanical properties. When these other flame retardants are additionally contained,
Suitable brominated bisphenol A-based compounds include brominated bisphenol A-based epoxy resins,
Suitable vinyl-based polymeric flame retardants having brominated substituents include brominated polystyrene and brominated benzyl acrylate. Among these flame retardants, brominated bisphenol A epoxy resins are particularly preferred.

[Additives] Also, for the purpose of improving flame retardancy,
An antioxidant such as a hindered phenol compound or a sulfurized compound may be added. Examples of other additives include an ultraviolet absorber, a coloring agent, an antistatic agent and the like.

Furthermore, fibrous materials such as glass fiber, asbestos, carbon fiber, aromatic polyamide fiber, potassium titanate fiber, steel fiber, ceramics fiber, Polon whisker fiber, mica, and the like are used for the purpose of improving mechanical properties. Powdery, powdery or plate-like inorganic fillers such as silica, talc, calcium carbonate, glass beads, glass flakes, clay, wollastonite and the like can also be added.

[Production Method] In general, the molding conditions preferably used for molding the flame-retardant polyester resin composition include a molten resin temperature of 250 ° C. or less and a molding cycle of 30 minutes.
Seconds or shorter, and the shorter the molding cycle, the better.However, in the case of molding a large molded product, a molded product with a complicated structure, or hot runner molding, it is necessary to increase the molten resin temperature in order to increase the fluidity of the resin. is there. However, when the usual flame-retardant polyester resin composition is molded at a molten resin temperature exceeding 250 ° C. and molding conditions of a molding cycle of 30 seconds / cycle or more, deterioration of the molten resin is promoted. In particular, when the temperature of the molten resin is 260 ° C. or more and the molding cycle is 60 seconds / cycle or more, the deterioration of the resin becomes remarkable in the ordinary flame-retardant polyester resin composition. The molten resin temperature refers to the temperature of the resin inside the molding machine cylinder.

The flame-retardant polyester resin composition of the present invention is characterized in that a resin molded product having excellent appearance and color tone can be obtained even under these poor molding conditions. That is, the flame-retardant polyester resin composition of the present invention has a melting resin temperature of 260 ° C. or more and a molding cycle of 60 seconds / cycle, which are conditions that enable molding of a large-sized molded article or a molded article having a complicated structure. Even with the above conditions,
There is a remarkable feature in that a resin molded product having excellent appearance and color tone can be obtained.

The features of the present invention, which can obtain a resin molded product having excellent appearance and color tone, are also applicable to the case of molding a resin by hot runner molding. The hot runner is a mold in which the runner portion of the mold is heated so as not to be solidified similarly to the molding machine cylinder. In the case of hot runner molding, the molten resin is maintained at a high temperature in the runner portion not only inside the cylinder but also inside the mold, and there is stagnation. When the conductive resin composition is used, a molded article excellent in appearance and color tone can be obtained.

That is, in the flame-retardant polyester resin composition of the present invention, molding conditions of a molten resin temperature of 260 ° C. or more and a molding cycle of 60 seconds or more can be used as molding conditions for large molded articles. When the flame-retardant polyester resin composition of the present invention is molded under these conditions, a large molded product having a good surface appearance or a molded product having a complicated structure is obtained when molding a large molded product such as a housing of an electric product. Can be obtained.

[0036]

Embodiments will be described below with reference to embodiments. Compositions are in parts by weight.

Examples 1-2 and Comparative Examples 1-4 Polybutylene terephthalate (intrinsic viscosity 0.86), brominated polycarbonate (polycarbonate repeating unit 3 to 4)
5), metal phosphate (sodium phosphate), phosphate (trimethyl phosphate), fluorine compound (polytetrafluoroethylene) and length 3 mm, cross-sectional diameter 13 μ
The glass chopped strands of m were uniformly mixed in the ratio (parts by weight) shown in Table 1 with a V-type blender to prepare a mixture of various resins. The obtained mixture is melt-kneaded at a barrel temperature of 260 ° C. by a twin screw extruder having a diameter of 44 mm, and the thread taken out of the die is cooled and cut to a length of 3 to 3 mm.
A pellet for molding having a diameter of 6 mm and a diameter of 2 to 4 mm was obtained.

Next, these pellets were dried with hot air at 130 ° C. for 5 hours, and then a test piece mold was attached to an 8.3 oz. Injection molding machine. The molten resin temperature was 270 ° C., the mold temperature was 60 ° C., and the injection pressure was 700 kg / cm. ^2. A flat plate specimen having a thickness of 1.0 mm, 50.0 mm × 80.0 mm was molded under molding conditions of a cooling time of 20 seconds, a total cycle of 35 seconds and 600 seconds. The results of evaluating the characteristics of these test pieces are shown in Table 1 together with the composition.

In Table 1, the surface appearance of the molded product was determined by the color difference ΔE.
And gloss. The color difference ΔE is a numerical value that expresses the characteristic of visible radiation or the appearance of visual perception whose difference in properties is recognized due to the difference in spectral energy. The value of the molded product obtained in a molding cycle of 35 seconds and the molding cycle Expressed as the difference between the values of the molded articles obtained in 600 seconds.
Gloss refers to the reflectance of visible light irradiated at an incident angle of 60 degrees. The surface appearance was determined to be good if the glossiness exceeded 80% and the color difference was 2.5 or less. On the other hand, the melt heat stability is such that the intrinsic viscosity number (η) of the molded product is 0.5.
80 or more were judged to be good. In addition, the combustion test
Performed based on the L94 standard, the thickness of the molded product is 0.7mm
It evaluated with t.

The meanings of the abbreviations used in Table 1 and in the description of the present embodiment are summarized below.

[0041]

[Table 1]

All compositions in the figures are shown in parts by weight based on 100 parts by weight of polybutylene terephthalate. Gloss is the reflectance when visible light is irradiated at an incident angle of 60 degrees, and the unit is%. The molded product surface appearance was judged to be good when the glossiness exceeded 80%. -When the intrinsic viscosity of the molded product was 0.80 or more, it was judged that the melt heat stability was good.

From Table 1, as shown in the present invention, when the metal phosphate alone is used as in Comparative Examples 1 and 2, the melt heat stability is good, but the color difference of the molded product is large and the gloss is high. 6 degrees
It is as low as 0% or less. When phosphoric acid ester was used alone as in Comparative Examples 3 and 4, the color difference of the molded product was small and the glossiness was high, but the thermal stability at the time of melting was not good, and the intrinsic viscosity of the molded product was lowered. Is big. On the other hand, when a metal phosphate and a phosphoric acid ester are used in combination as in Examples 1 and 2, the gloss of the molded product is increased to 85% or more, a color difference is small, and a molded product with a small decrease in intrinsic viscosity is obtained. Is shown.

[0044]

According to the present invention, a resin composition having excellent surface appearance, especially color tone and gloss, of a molded article while maintaining excellent heat resistance, mechanical properties, and flame retardancy, and a home appliance comprising the same are provided. A molded product for a product can be obtained. Further, a flame-retardant polyester resin composition having a stable molten resin viscosity can be obtained even under a long molding cycle and molding conditions at a high molten resin temperature.

Claims (4)

[Claims] 1. A composition comprising 3 to 60 parts by weight of a brominated polycarbonate and 0.01 to 4 parts by weight of a phosphorus compound per 100 parts by weight of an aromatic polyester, wherein the phosphorus compound is a phosphoric ester or a phosphite. And at least one flame-retardant polyester resin composition selected from the group consisting of phosphoric acid and phosphorous acid metal salts. 2. The flame-retardant polyester resin composition according to claim 1, wherein the aromatic polyester is polybutylene terephthalate and / or polyethylene terephthalate. 3. A molded article for home appliances comprising the flame-retardant polyester resin composition according to claim 1. 4. A molded article for home appliances, wherein the flame-retardant polyester resin composition according to claim 1 or 2 is molded under a molding condition of a molten resin temperature of 260 ° C. or more and a molding cycle of 60 seconds or more. Production method.