JP2008013622A - Polyarylate resin composition and its preparation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyarylate resin composition which is a resin composition comprising a polyarylate and a polyester and is yielding a transparent molded product by suppressing the formation of "wavy" patterns, and a preparation method thereof. <P>SOLUTION: In the preparation method of the polyarylate resin composition, 20-80 pts.mass polyarylate (A) and 80-20 pts.mass polyalkylene terephthalate (B) are separately and continuously fed to a twin screw extruder using a volumetric feeder and subjected to melt kneading. Here, the actual feed rates of components (A) and (B) per minute are within ±5% from the set values. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polyarylate resin composition excellent in transparency and a method for producing the same.

  In addition to being generally transparent, the resin composition comprising polyarylate and polyester is superior in heat resistance to that of the polyester resin alone, and better in chemical resistance than that of the polyarylate resin alone. Furthermore, it is excellent in gas barrier properties and ultraviolet absorption properties.

  As an application example of a resin composition comprising polyarylate and polyester, a polyester sheet is excellent in transparency, chemical resistance and secondary processability, but has insufficient heat resistance. Sheets with improved heat resistance, which are molded from a resin composition comprising the following, have been proposed (Patent Documents 1 and 2).

  In addition, hollow containers using polyester resin are excellent in transparency and mechanical properties, and are used for food such as soft drinks, mineral water, seasonings, edible oils, alcoholic beverages, and non-food such as cosmetics and detergents. Widely used in applications. However, when filling pharmaceuticals such as eye drops, sterilization at high temperature requires heat resistance of the container. However, in Patent Document 3, a resin composition comprising polyarylate and polyester is excellent in heat resistance. Therefore, it is disclosed that it can be suitably used for pharmaceutical use. Polyarylate is generally excellent in ultraviolet absorptivity, and in the case of a pharmaceutical container, a resin composition of polyarylate and polyester may be used to prevent deterioration of medicinal components due to ultraviolet rays.

  Next, regarding a method for producing a resin composition of polyarylate and polyester, Patent Document 4 discloses a method of mixing in a molten state. However, since polyarylate and polyester are not always compatible, It is disclosed that a transparent resin composition can be obtained by using a compatibilizing agent that promotes the transesterification reaction during kneading.

However, when the resin composition is melt-molded by a method such as injection molding, it should be a molded body with uniform transparency, but a “fluctuation” pattern is often seen inside the molded body. appear. Since polyarylate and polyester lack compatibility, if a compatibilizer is not used, a transparent resin composition may not be formed and white turbidity may occur. However, this “fluctuation” pattern does not refer to a phenomenon such as cloudiness when a compatibilizer is not used, but to a hazy flow pattern such as a hot flame generated in water by heat convection. This is a problem in that it is difficult to obtain a completely transparent molded product because of this “fluctuation” pattern.
JP-A-49-61247 JP 50-96652 A JP-A-53-40048 JP 58-147449 A

  The present invention solves the above problems, and in a resin composition comprising polyarylate and polyester, a “fluctuation” pattern is unlikely to occur, and a polyarylate-based resin composition capable of obtaining a transparent molded product and its Providing a manufacturing method is a technical problem.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention obtained polyarylate and polyester as a main raw material when melt-kneading polyarylate and polyester with a twin-screw extruder to obtain a resin composition. Reached the present invention by knowing that the above problem can be solved by adding a specific organic acid salt to the extruder accurately and separately, so that the mixing ratio with the polyester is always constant. did.

  That is, the gist of the present invention is as follows.

(1) A resin composition comprising 20 to 80 parts by mass of polyarylate (A) and 80 to 20 parts by mass of polyalkylene terephthalate (B), and having a thickness of 3 mm obtained by injection molding the resin composition A polyarylate-based resin composition characterized in that at least the surface of the plate does not have a wavy pattern.
(2) 20-80 parts by mass of polyarylate (A) and 80-20 parts by mass of polyalkylene terephthalate (B) are continuously fed to a twin screw extruder using separate metering devices, and melt kneaded. In the process, a method for producing a polyarylate-based resin composition, wherein the actual supply amount of each component (A) and (B) per minute is supplied with a supply error within ± 5% of the set value.
(3) For a total of 100 parts by mass of polyarylate (A) and polyalkylene terephthalate (B), 0.005 to 0.10 parts by mass of organic acid salt (C) of Group IA or IIA metal is added to polyarylate ( A) and / or a polyalkylene terephthalate (B) is mixed, The manufacturing method of the polyarylate-type resin composition as described in said (2) characterized by the above-mentioned.
(4) The method for producing a polyarylate-based resin composition as described in (2) or (3) above, wherein the polyalkylene terephthalate (B) is polyethylene terephthalate.
(5) The organic acid salt (C) of a group IA or group IIA metal is at least one selected from sodium acetate, potassium acetate, calcium stearate, and magnesium stearate (3) or The manufacturing method of the polyarylate-type resin composition as described in (4).
(6) The polyarylate (A) and the polyalkylene terephthalate (B) are supplied to a twin-screw extruder using a mass type quantitative supply device, and any one of the above (2) to (5) A method for producing a polyarylate-based resin composition.

  Since the polyarylate-based resin composition of the present invention has no “fluctuation” pattern on at least the surface of a 3 mm thick plate obtained by injection molding of this resin composition, it is more heat resistant than the polyester resin alone. In addition to the general properties of a resin composition composed of polyarylate and polyester, which is superior in chemical resistance compared to the case of polyarylate resin alone, it is possible to obtain a molded article excellent in transparency. is there.

  Moreover, according to the manufacturing method of this invention, the polyarylate-type resin composition which has said advantage can be manufactured stably, and industrial utility value is very high.

  Hereinafter, the present invention will be described in detail.

  The polyarylate-based resin composition of the present invention contains polyarylate (A) and polyalkylene terephthalate (B) as main components. First, polyarylate (A) will be described.

  The polyarylate (A) used in the present invention is an aromatic polyester polymer having a repeating unit composed of an aromatic dicarboxylic acid residue and a bisphenol residue.

  Materials for introducing aromatic dicarboxylic acid residues include terephthalic acid, isophthalic acid, phthalic acid, chlorophthalic acid, nitrophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7- Naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, methylterephthalic acid, 4,4'-biphenyldicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 4,4'-biphenyletherdicarboxylic acid, 4,4'-diphenylmethane Examples include dicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, 4,4′-diphenylisopropylidenedicarboxylic acid, 1,2-bis (4-carboxyphenoxy) ethane, and 5-sodium sulfoisophthalic acid. Terephthalic acid and isophthalic acid are preferred, and it is particularly preferred to use a mixture of both from the viewpoint of melt processability and mechanical properties. Usually, the mixing molar ratio (terephthalic acid / isophthalic acid) is arbitrarily in the range of 100/0 to 0/100, preferably 70/30 to 30/70, and most preferably 60/40 to 40/60. .

  Bisphenols as raw materials for introducing bisphenol residues are 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2 , 2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 4,4'-dihydroxydiphenylsulfone, 4,4'- Examples include dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenyl ketone, 4,4′-dihydroxydiphenylmethane, and 1,1-bis (4-hydroxyphenyl) cyclohexane. These compounds may be used alone or in combination of two or more. Among these compounds, 2,2-bis (4-hydroxyphenyl) propane (hereinafter abbreviated as bisphenol A) is preferably used, and optimally used alone.

  The inherent viscosity of the polyarylate (A) is usually 0.4 to 1.0, preferably 0.5 to 0.8, from the viewpoint of mechanical properties and fluidity. When the inherent viscosity is less than 0.4, the molecular weight of the resulting resin composition is lowered, so that the mechanical properties may be reduced. Conversely, when the inherent viscosity is more than 1.0, the melt viscosity is increased. When making a resin composition, poor dispersion may occur and transparency may be impaired.

  The polyalkylene terephthalate (B) used in the present invention is a polyester having a repeating unit composed of a terephthalic acid residue and an alkylene diol residue.

  Specific examples of raw materials for introducing an alkylene diol residue include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, Examples include aliphatic diol components such as 1,5-pentanediol, 1,6-hexanediol and neopentyl glycol, and diol components having an alicyclic group such as 1,4-cyclohexanedimethanol and 1,4-cyclohexanediethanol. The These compounds may be used alone or in combination of two or more. Among these compounds, it is preferable to use ethylene glycol, and polyethylene terephthalate obtained by using this alone is optimal for obtaining a resin composition having good heat resistance and gas barrier properties.

  The intrinsic viscosity of the polyalkylene terephthalate (B) is usually 0.5 or more, preferably 0.6 to 1.2. When the intrinsic viscosity is less than 0.5, the molecular weight of the resulting resin composition is lowered, so that the mechanical properties may be deteriorated. Conversely, when it exceeds 1.2, poor dispersion occurs during melt-kneading. Since transparency may be impaired, both are not preferable.

  The blending ratio of the polyarylate (A) and the polyalkylene terephthalate (B) is such that the (A) component is 20 to 80 parts by mass, the (B) component is 80 to 20 parts by mass, and the (A) component is 30 to 30 parts. The component (B) is preferably 70 to 30 parts by mass with respect to 70 parts by mass. When the polyarylate (A) is less than 20 parts by mass, the resulting resin composition has insufficient heat resistance, or the ultraviolet blocking effect inherent in the component (A) is weakened, and conversely exceeds 80 parts by mass. And the secondary workability of the resin composition is deteriorated, which is not preferable.

  The polyarylate-based resin composition of the present invention contains polyarylate (A) and polyalkylene terephthalate (B) as main components, and contains an organic acid salt (C) of a Group IA or Group IIA metal. Is preferred.

  The organic acid salt (C) of the Group IA or Group IIA metal used in the present invention is selected from those which are alkaline and promote the transesterification reaction and which dissolve in the resin composition and do not impair the transparency. That is, group IA or group IIA metals are sodium, potassium, lithium, calcium, magnesium, strontium, barium, etc., and organic acids are formic acid, acetic acid, propionic acid, butyric acid, valeric acid, lauric acid, myristic acid, palmitic acid Examples include acids, stearic acid, montanic acid, benzoic acid and the like. Among these combinations, sodium acetate, potassium acetate, calcium stearate, and magnesium stearate are preferable in terms of the transesterification promoting effect and the transparency and mechanical properties of the resulting resin composition.

   The compounding ratio of the organic acid salt (C) of Group IA or Group IIA metal is 0.005 to 0.10 parts by mass with respect to 100 parts by mass in total of polyarylate (A) and polyalkylene terephthalate (B), It is more preferable to set it as 0.01-0.08 mass part. When the component (C) is less than 0.005 parts by mass, the transesterification reaction is not promoted and the transparency of the resin composition tends to be impaired, and when it exceeds 0.10 parts by mass, the resulting resin composition is hydrolyzed. This is not preferable because the mechanical properties are likely to deteriorate.

  To the polyarylate-based resin composition of the present invention, pigments, weatherproofing agents, oxidative degradation inhibitors, flame retardants, mold release agents, and the like can be added as long as the properties are not impaired.

  The inherent viscosity of the polyarylate resin composition of the present invention at 25 ° C. at a concentration of 1 g / dl using a 6/4 mixture of phenol / 1,1,2,2-tetrachloroethane as a solvent is 0.50 dl / g or more. It is preferable that it is 0.55 dl / g or more. If the inherent viscosity is less than 0.50 dl / g, the mechanical properties may deteriorate, which is not preferable.

  When the polyarylate resin composition is produced, if the dispersion and transesterification of each component by melt kneading of the polyarylate (A) and the polyalkylene terephthalate (B) are sufficient, the resulting resin composition is transparent. However, when it is insufficient, the resin components are not completely compatibilized, so that the resin composition becomes opaque like a translucent or cloudy state. When evaluating such transparency, generally haze (cloudiness) calculated by the following formula (1) is used.

Haze (cloudiness) = 100 × [100-parallel light transmittance (%)] / total light transmittance (%) (1)
When there is no haze and the transparency is excellent, the haze value is small, and when there is haze and the transparency is poor as in the translucent state, the haze value is large. The polyarylate resin composition of the present invention preferably has a haze of 7.0 or less on a plate having a thickness of 3 mm. When haze exceeds 7.0, dispersion | distribution or transesterification of each resin component which comprises a resin composition is inadequate, and the transparency of the molded article using this resin composition is easy to be impaired.

  The polyarylate-based resin composition of the present invention has no “fluctuation” pattern on at least the surface of a 3 mm thick plate obtained by injection molding the resin composition, and is not on the back surface. preferable. By having such characteristics, a “fluctuating” pattern, that is, a hazy flow pattern such as a heat wave generated in water by heat convection, etc. can be seen in a transparent molded body. Therefore, if this resin composition is molded, a molded article with higher transparency can be obtained.

  Next, the manufacturing method of the polyarylate-type resin composition of this invention is demonstrated. As a method for producing a resin composition comprising polyarylate (A) and polyalkylene terephthalate (B), a melt-kneading method is preferred, and it is particularly preferable to use a twin-screw extruder, particularly a co-rotating type. It is preferable in terms of easy adjustment of the degree and easy continuous production.

  In the present invention, the polyarylate (A) and the polyalkylene terephthalate (B) can be obtained by continuously supplying from the base supply port of the extruder and melt-kneading. In particular, the polyarylate (A) and the polyalkylene terephthalate (B) can be continuously fed with high accuracy by using independent quantitative feeders so that the ratio of the components (A) and (B) is always constant. This is a point in obtaining a resin composition that is a molded article having excellent transparency.

  When the polyarylate (A) and the polyalkylene terephthalate (B) are mixed in advance and then supplied to the extruder using one fixed supply device, the resulting molded product using the resin composition has a “fluctuation” shape. May occur, which is not preferable. This is due to the occurrence of composition spots (A) and (B) due to static electricity and the difference in specific gravity during the dispensing process from the raw material mixing apparatus, the charging process to the quantitative supply apparatus, or the retention in the quantitative supply apparatus. is there. Since the polyarylate (A) and the polyalkylene terephthalate (B) have different refractive indexes and greatly different melt viscosities, both the refractive index and melt viscosity are obtained depending on the blending ratio of (A) and (B). This is presumed to be considerably different. (A) Even if it is a mixture of compositions having slightly different mixing ratios of (B), a difference in melt viscosity does not give a completely uniform composition in the molding process, and the refractive index is different. For this reason, it will be visually recognized as a “fluctuation” pattern in the molded product, and transparency will be impaired.

  Even when (A) and (B) use separate quantitative feeders, the accuracy of supply in a long time unit (long term) such as 1 hour is good, but in a shorter time unit (short term). If the supply accuracy is not good, the mixed product of (A) and (B) is not much different from the case where the mixed product is supplied all at once. As the supply accuracy of the quantitative supply device (A) and (B) in the present invention, the actual supply amount per minute should be within ± 5%, preferably within ± 3% of the set value. However, it is necessary to obtain a transparent molded body.

  Next, with respect to the organic acid salt (C) of Group IA or Group IIA metal, a single metering device may be used, or it is premixed with polyarylate (A) and / or polyalkylene terephthalate (B). May be. However, since the ratio of the component (C) to the whole is low and the amount supplied to the extruder is too small, the accuracy of the feeder may be adversely affected.

  The quantitative supply device used in the present invention can be selected from a screw feeder, a table feeder, a belt feeder, etc., but the raw material cutting mechanism of the device is automatically adjusted by mass measurement rather than the positive displacement quantitative supply device. A mass type quantitative supply device is preferable in order to improve supply accuracy.

The extrusion temperature in the twin-screw extruder of the present invention may be any temperature at which the polyarylate (A) and the polyalkylene terephthalate (B) are melted. Is preferable. Although the screw speed of the extruder differs depending on the blending ratio of (A) and (B), it cannot be unconditionally limited. However, it is possible to obtain the minimum number of revolutions that can be made transparent by melting and kneading both components. It is preferable because the molecular weight of the composition can be increased. Moreover, it is preferable to provide one or more vent ports in the extruder to reduce the pressure. Furthermore, it is preferable that (A) and (B) be dried in advance and supplied to the twin-screw extruder because a decrease in the molecular weight of the resin composition due to hydrolysis can be suppressed. In addition, if the said extruder has a side feeder, you may supply a part or all of a polyarylate (A) and / or a polyalkylene terephthalate (B) from a side feeder.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited only to an Example. In addition, the raw material used in the Example, the fixed_quantity | feed_rate supply apparatus, and the evaluation method of each characteristic are as follows.
1. Raw materials used (1) Polyarylate U polymer (Inherent viscosity 0.70) made by Unitika, consisting of bisphenol A and terephthalic acid / isophthalic acid. Hereinafter, it is referred to as “PAR”.
(2) Polyethylene terephthalate SA1206 (Intrinsic viscosity 1.07) manufactured by Unitika. Hereinafter, it is referred to as “PET”.
(3) Sodium acetate Special grade reagent manufactured by Wako Pure Chemical Industries, Ltd. of sodium acetate without crystal water. Hereinafter referred to as “NaOAc”.

2. Fixed quantity supply device (1) Mass type Loss-in-weight type twin screw meter CE-W-1 manufactured by Kubota Corporation. The screw rotational speed is automatically adjusted so that the set supply amount input to the apparatus control unit is equal to the actual supply amount.
(2) Positive displacement type KUBOTA twin screw meter CE-W-0. A calibration curve of the actual discharge amount with respect to the screw rotation number is created in advance, and the screw rotation number that sets a desired supply amount only at the start of supply is set.

3. Evaluation method for each characteristic (1) Supply error (raw material supply accuracy)
The raw material discharged from the supply device is sampled five times in succession for 1 minute each, the maximum value and minimum value are converted into the supply amount per hour, and the difference from the supply set value is expressed by the following formula (2) The value calculated in (5) was defined as the supply error.

Supply error (%) = 100 x [Actual supply amount (kg / h)-Supply set value (kg / h)] / Supply set value (kg / h) (2)
(2) Inherent viscosity Measured at a concentration of 1 g / dl and a temperature of 25 ° C. using a mixture of phenol / 1,1,2,2, -tetrachloroethane in a mass ratio of 6/4 at a temperature of 25 ° C. and expressed in units of dl / g .
(3) Haze A resin composition pellet formed by injection molding into a 3.0 mm thick plate was measured according to JIS K7361-1.
(4) Presence / absence of “fluctuation” pattern Observe the same plate used for the haze measurement in (3), see “fluctuation” pattern, and see “fluctuation” pattern. The ones that were not possible were marked with ○.

(Examples 1-4, Comparative Examples 1-3)
Made by TOSHIBA MACHINERY CO., LTD. Using a separate quantitative feeder of PAR and NaOAc that were dried at 120 ° C for 8 hours or more using a hot air dryer and PET that was also dried at 120 ° C for 8 hours or more. It was continuously supplied to the main supply port of the TEM-37BS twin screw extruder TEM-37BS. The resin component was melted and kneaded by this extruder, and the resin composition taken up in a strand form from the die orifice was immersed in a water bath to be cooled and solidified, and was cut by a pelletizer to obtain resin composition pellets. The raw materials used were 15 kg in total of PAR and PET. Combined with the mixing ratio of PAR and NaOAc, the set supply amount of those mixtures, the set supply amount of PET, the screw rotation speed of the extruder, the barrel temperature of the extruder, the feed error of the raw material, and the evaluation result of the obtained resin composition Table 1 shows.

As is clear from Table 1, the plate obtained by injection molding of the resin compositions obtained in Examples 1 to 4 has a haze of less than 7 and does not generate a “fluctuation” pattern, and is a transparent molded product. It was.

On the other hand, the resin compositions obtained in Comparative Examples 1 to 3 in which the actual supply amount per minute of polyarylate (A) and polyethylene terephthalate (B) was supplied with a supply error exceeding ± 5% of the set value, respectively. Even if the haze was more than 7 or less than 7, the plate of the object had a “fluctuation” pattern and was inferior in transparency.
(Comparative Examples 4 and 5)
Main feed port of EM-37BS co-rotating twin screw extruder manufactured by TOSHIBA MACHINE CO., LTD. Using a mass-quantitative quantitative feeder that is a uniform mixture of PAR, PET and NaOAc dried at 120 ° C for 8 hours or more using a hot air dryer Continuously fed. The resin component was melted and kneaded by this extruder, and the resin composition taken up in a strand form from the die orifice was immersed in a water bath to be cooled and solidified, and was cut by a pelletizer to obtain resin composition pellets. The raw materials used were 15 kg in total of PAR and PET. Table 2 shows the mixing ratio of PAR, PET and NaOAc, the set supply amount of these mixtures, the screw rotation speed of the extruder, the barrel temperature of the extruder, the feed error of the raw materials, and the evaluation results of the obtained resin composition. .

As is apparent from Table 2, the resin composition obtained in Comparative Examples 4 and 5 in which the polyallylate (A), polyethylene terephthalate (B), and sodium acetate (C) were uniformly mixed and supplied to the twin-screw extruder. Even if the haze exceeded 7 or less than 7, the plate of the object had a “fluctuation” pattern and was inferior in transparency.

Claims (6)

  A resin composition comprising 20 to 80 parts by mass of polyarylate (A) and 80 to 20 parts by mass of polyalkylene terephthalate (B), and at least a 3 mm thick plate obtained by injection molding the resin composition A polyarylate-based resin composition characterized in that the surface has no wavy pattern.   When the polyarylate (A) 20 to 80 parts by mass and the polyalkylene terephthalate (B) 80 to 20 parts by mass are separately supplied to a twin-screw extruder using separate metering apparatuses, and melt kneaded ( A) (B) A method for producing a polyarylate-based resin composition, wherein the actual supply amount per minute of each component is supplied with a supply error within ± 5% of the set value.   For a total of 100 parts by mass of polyarylate (A) and polyalkylene terephthalate (B), 0.005 to 0.10 parts by mass of organic acid salt (C) of Group IA or IIA metal is added to polyarylate (A) and 3. The method for producing a polyarylate-based resin composition according to claim 2, wherein the polyarylate terephthalate (B) is mixed.   The method for producing a polyarylate-based resin composition according to claim 2 or 3, wherein the polyalkylene terephthalate (B) is polyethylene terephthalate.   The organic acid salt (C) of a Group IA or Group IIA metal is at least one selected from sodium acetate, potassium acetate, calcium stearate, and magnesium stearate. A method for producing a polyarylate-based resin composition. The polyarylate-based resin composition according to any one of claims 2 to 5, wherein the polyarylate (A) and the polyalkylene terephthalate (B) are supplied to a twin-screw extruder using a mass type quantitative supply device. Manufacturing method.