JPH0113741B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for producing a polyester resin composition, and particularly to a method for obtaining a polyester resin composition with excellent additive dispersibility. <Prior Art> Thermoplastic polyester resins, particularly polyalkylene terephthalate resins, have high heat resistance and excellent physical properties such as mechanical properties, electrical properties, and chemical resistance, and are widely used in industrial products. In addition, polyester resins containing various additives are also widely used in order to improve the drawbacks of the above-mentioned polyester resins or to further improve their properties. For example, reinforcing agents such as glass fiber or carbon fiber, talc, mica, calcium carbonate, etc. are added to improve rigidity and heat resistance, and various organic halogen flame retardants, antimony trioxide, etc. are added to impart flame retardancy. flame retardant aids, various impact modifiers to further improve impact strength, and various other additives such as antioxidants, colorants, ultraviolet absorbers, lubricants, core materials, antistatic agents, etc. agent is added. These additives may be used as a single type of additive, but they are often used in combination if multiple effects are expected. These additives are sometimes added during polyester polymerization, but when granulated using an extruder,
Alternatively, it is generally added directly during the molding step (during injection molding, extrusion molding) to obtain the final product. Although practically useful polyester molded articles can be obtained in many cases by these methods, the uniformity of dispersion of powdered additives is not always satisfactory. Especially when adding additive (B) having a higher melting point than the polyester,
(B) has a strong tendency to agglomerate, and in the thus obtained polyester molded product, the agglomerated additives may sometimes be detected as foreign matter on the product surface, reducing the commercial value due to poor appearance. Furthermore, even if aggregates are not observed on the molded surface, the presence of aggregates inside the molded material may lead to unexpected deterioration of electrical and mechanical properties. <Object of the invention> The object of the invention is to provide powder additives with excellent dispersibility,
The object of the present invention is to provide a method for producing a polyester resin composition with good properties. <Structure of the Invention> The present invention provides a method for producing a resin composition in which (A) a linear aromatic polyester and (B) a powder additive having a melting point higher than the melting point of the polyester are uniformly dispersed. This method of producing a polyester resin composition is characterized in that the additive (B) is melt-kneaded in advance with a polyester elastomer (C) and then mixed with a linear aromatic polyester (A). In the present invention, the linear aromatic polyester used as component (A) is one in which terephthalic acid or its ester-forming transparent conductor is used as the acid component, and a glycol having 2 to 10 carbon atoms or its ester-forming derivative is used as the glycol component. The main targets are the obtained linear saturated polyesters, such as polyethylene terephthalate, polypropylene terephthalate, polytetramethylene terephthalate (polybutylene terephthalate), polyhexamethylene terephthalate, polycyclohexane, 1,4-dimethylol terephthalate, polyneopentyl terephthalate, etc. Can be mentioned. Among these, polyethylene terephthalate and polybutylene terephthalate are particularly preferred. These aromatic polyesters may be used alone or as a mixture of two or more. Other polyesters may also be used, such as those in which part of the terephthalic acid component or the glycol component having 2 to 10 carbon atoms is replaced with another copolymer component as the acid component. Such copolymerization components include, for example, halogen-substituted phthalic acids such as isophthalic acid, phthalic acid, tetrabromophthalic acid, and tetrabromoterephthalic acid; alkyl-substituted phthalic acids such as methylterephthalic acid and methylisophthalic acid; 2,6
- Naphthalene dicarboxylic acids such as naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, and 1,5-naphthalene dicarboxylic acid; diphenyl dicarboxylic acids such as 4,4'-diphenyl dicarboxylic acid and 3,4'-diphenyl dicarboxylic acid; Acids; 4,
Aromatic dicarboxylic acids such as 4'-diphenoxyethane dicarboxylic acid; aliphatic or alicyclic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, decadicarboxylic acid, cyclohexane dicarboxylic acid, etc.; trimethylene glycol,
Aliphatic diols such as tetramethylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanedimethanol, etc.; dihydroxybenzenes such as hydroquinone, resorcinol, etc.; 2.
2-bis(4-hydroxyphenyl)propane,
Bisphenols such as bis(4-hydroxyphenyl) sulfone; aromatic diols such as ether diols obtained from bisphenols and glycols such as ethylene glycol; polyoxyethylene glycol, polyoxypropylene glycol, and Examples include polyoxytetramethylene glycols such as oxytetramethylene glycol; oxycarboxylic acids such as ε-oxycaproic acid, hydroxybenzoic acid, hydroxyethoxybenzoic acid, and the like. One or more of these copolymerization components can be used, and the proportion thereof is 20 mol% or less, especially 10 mol% or less, based on the total dicarboxylic acid (half of the amount of oxycarboxylic acid is calculated as carboxylic acid). It is preferable. Furthermore, these linear aromatic polyesters may contain branching components such as trifunctional acids such as tricarballylic acid, trimellisic acid, trimellitic acid, or tetrafunctional ester-type acids such as pyromellitic acid, and/or glycerin, trimethylolpropane, Alcohols with trifunctional or tetrafunctional ester form properties such as pentaerythritol, etc.
It may be copolymerized in an amount of 1.0 mol% or less, preferably 0.5 mol% or less, more preferably 0.3 mol% or less. The linear aromatic polyester used herein is preferably a polymer having an intrinsic viscosity ([η]) of 0.40 or more, particularly 0.50 or more. Here, the intrinsic viscosity is 1.2 in orthochlorophenol at 35℃.
This is a value calculated from the solution viscosity at a concentration of g/100ml. The above-mentioned linear aromatic polyester can be produced by a conventional production method, such as a melt polycondensation reaction or a method combining this with a solid phase polymerization reaction. For example, to explain an example of manufacturing polytetramethylene terephthalate, terephthalic acid or its ester-forming derivative (for example, lower alkyl ester such as dimethyl ester, monomethyl ester, etc.) and tetramethylene glycol are reacted with heat in the presence of a catalyst, and then Polytetramethylene terephthalate can be produced by a method in which the resulting glycol ester of terephthalic acid is subjected to a polymerization reaction to a predetermined degree of polymerization in the presence of a catalyst. The additive (B) used in the present invention is polyester
It is a powder with a melting point higher than that of (A). The powdered additive (B) of the present invention preferably has an average particle size of 200μ or less;
This is particularly noticeable in additives with fine particle sizes of 50μ or less. Examples of the powder additive (B) of the present invention include mica,
Inorganic fillers such as talc, silica, glass beads, glass flakes, and wollastonite, coloring agents such as carbon black and titanium oxide, flame retardant aids such as antimony trioxide, antimony pentoxide, and zinc nitrate, and decabromobiphenyl. Examples include flame retardants such as ether and halogenated polycarbonate. The polyester elastomer (C) used in the present invention is a block copolymer having rubber-like elasticity due to repeated bonding between aromatic polyester as a hard segment and polyether as a soft segment. Examples of aromatic polyesters that form hard segments include terephthalic acid, isophthalic acid,
Other aromatic dicarboxylic acids such as ethylene bis(p-oxybenzoic acid) and naphthalene dicarboxylic acid are used as acid components, and aliphatic alkylene glycols having 2 to 10 carbon atoms, 1,4-cyclohexanedimethanol, 1,4-cyclohexanedimethanol Examples include those obtained by using glycols containing an alicyclic group, such as, or glycols containing an aromatic group, such as 1,4-benzenedimethanol and 1,4-benzenedimethanol as a glycol component. Further, the acid component and the glycol component may be used singly or in combination of two or more thereof, or may contain a small amount of aliphatic dicarboxylic acid as a constituent acid component. The polyether forming the soft segment is preferably an aliphatic polyether with a molecular weight of 350 to 6000.
In particular, polyalkylene oxide glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol are preferred. The polyether may be a random copolymer or a block copolymer.
Moreover, two or more types of polyethers can also be used in combination. As the polyester elastomer (C), one in which the soft segment accounts for 10 to 90% by weight can be used, and one in which the soft segment accounts for 40 to 60% by weight is particularly preferable. In the present invention, the amount of component (B) added is 100% of component (A).
It is preferably 0.1 to 100 parts by weight. Polyester elastomer (C) is powdered additive (B)
It is used to uniformly disperse the polyester in the linear aromatic polyester (A), and basically the smaller the amount used, the better. For example, the amount of component (C) is preferably 15 parts by weight or less per 100 parts by weight of component (A). The mixing ratio of additive (B) and polyester elastomer (C) is regulated by the amount of additive ultimately required to improve the polyester. ) Considering the melt-kneading properties of polyester elastomer (C) 100
Additive (B) is preferably 1.0 to 1000 parts by weight, particularly preferably 10 to 800 parts by weight, and even more preferably 50 to 800 parts by weight.
Preferably it is 4000 parts by weight. If the amount of the additive is too small, the effect of pre-kneading will not be significant, and if it is too large, the kneading becomes difficult. The additive (B) and the molten polyester elastomer (C) can be mixed by adding the additive (B) during the production of the polyester elastomer, or by melt-kneading the additive (B) and the polyester elastomer (C) using a kneader or extruder. Although any method may be used, kneading using an extruder is the most common method. In addition to the powdery additive (B) with a high melting point, the polyester composition of the present invention can contain a fibrous additive such as glass fiber or carbon fiber, and a compound with a lower melting point than the polyester resin. Compounds used to improve the properties of the linear aromatic polyester (A) with such low melting point compounds include polyethylene, polypropylene, polystyrene, polycarbonate, ethylene vinyl acetate copolymer, ethylene acrylate copolymer, etc. Various compounds such as thermoplastic polymers, epoxy compounds obtained from halogenated bisphenol A, flame retardants such as low molecular weight halogenated polycarbonates, and epoxy compounds can be mentioned. When a polyester composition containing such a low melting point compound, a linear aromatic polyester (A), and a powder additive (B) is subjected to molding, the uniform dispersibility of the powder additive (B) is determined by the low melting point compound. Although it tends to be worse than that of compositions that do not contain
By integrating the powder additive (B) with the polyester elastomer (C) in advance, the powder additive (B)
The uniform dispersibility in the resin composition is particularly good. The mixture of the additive (B) and the polyester elastomer (C) can be further granulated with the polyester (A) by melt-kneading, and this granulated product can be subjected to extrusion molding, injection molding, or the like. Alternatively, it can be mechanically mixed with polyester (A) and then directly subjected to extrusion molding, injection molding, or the like. <Effects of the Invention> In the polyester resin composition obtained by the present invention, additives are uniformly dispersed, and a molded article having good electrical properties and mechanical properties and a beautiful appearance can be produced. <Examples> The present invention will be explained in detail below using examples. The main characteristics were measured as follows. Impact strength: ASTM standard D-256 Tensile strength: ASTM standard D-638 Flammability: UL standard Subject94 Example 1 and comparative example 1 Polytetramethylene glycol with a molecular weight of 1500
80 parts by weight of antimony trioxide having an average particle size of 0.5 μm was blended with 20 parts by weight of polyester elastomer of polytetramethylene terephthalate containing 50% by weight, and the mixture was melt-kneaded in an extruder at a cylinder temperature of 200° C. and then granulated. 5 parts by weight of the obtained granules and the intrinsic viscosity [η] (O
-Measured at 35℃ using chlorophenol as a solvent)
50 parts by weight of dry polytetramethylene terephthalate (hereinafter abbreviated as PBT) with a diameter of 0.75, length 3
30 parts by weight of glass fiber having a diameter of 1.5 mm and 15 parts by weight of polycarbonate oligomer (average degree of polymerization 4, melting point 193°C) obtained from brominated bisphenol were melt-kneaded at a cylinder temperature of 270°C to obtain pellets for molding. Using this pellet, a disk having a thickness of 3.2 mm and a diameter of 5 cm was produced using a 5 oz. injection molding machine.
The characteristics of the disc were evaluated. The results are shown in Table 1. For comparison, 4 parts by weight of the above antimony trioxide and 1 part by weight of polyester elastomer were blended into a predetermined amount of PBT, glass fiber, and brominated polycarbonate oligomer without melt-kneading in advance, and pelletized using an extruder under the same conditions. and used for comparative evaluation. The evaluation results are also shown in Table 1. It is clear from Table 1 that the molded articles obtained by the present invention are particularly excellent in uniform dispersibility of the additive (antimony trioxide).

[Table] Example 2 Polycarbonate oligomer obtained from 50 parts by weight of dry PBT with an intrinsic viscosity [η] of 0.75, 30 parts by weight of glass fiber with a length of 3 mm, and brominated bisphenol (average degree of polymerization 4, melting point 193°C) ) 15 parts by weight were melt-kneaded in the same manner as in Example 1 to obtain pellets for molding. 95 parts by weight of these pellets and 5 parts by weight of the granulated molten mixture of polyester elastomer and antimony trioxide obtained in Example 1 were mixed and subjected to direct injection molding. The number of foreign particles in the obtained molded article was one, and the dispersibility was extremely good. Examples 3, 4, 5 Comparative Examples 2, 3, 4 In Example 1, instead of antimony trioxide, talc (average particle size 8μ), silica (average particle size 15μ) and titanium oxide (average particle size 0.3μ) were used. A granular material of a melt-kneaded product of a polyester elastomer and an additive was obtained in the same manner as in Example 1 except that the mixture was used. 25 parts by weight of this granule and 75 parts by weight of PBT having an intrinsic viscosity [η]=1.03 were mixed and injection molded. On the other hand, for comparison purposes, 75 parts by weight of the above PBT, 5 parts by weight of the polyester elastomer, and 5 parts by weight of the above additives were melt-kneaded in an extruder and then injection molded to obtain a molded article for characteristic evaluation. Table 2 shows the properties of these molded products. As is clear from Table 2, the composition obtained according to the present invention has excellent uniform dispersibility and strength.

[Table] Example 6, Comparative Example 5 In Example 3, instead of talc, the average particle size
Example 3 except that 0.5μ antimony trioxide is used.
An injection molded product was obtained in the same manner as (Example 6). For comparison, an injection molded product was obtained in the same manner as Comparative Example 2 (Comparative Example 5). Table 3 shows the properties of the molded product obtained.

【table】

Claims (1)

[Claims] 1. In producing a resin composition in which a linear aromatic polyester (A) and a powdered additive (B) having a melting point higher than the melting point of the polyester are uniformly dispersed,
Add the powdered additive (B) to the polyester elastomer (C) in advance.
Linear aromatic polyester (A) is obtained by melt-kneading the
A method for producing a polyester resin composition, characterized by mixing it with a polyester resin composition.