JP2011132287A - Method for lowering glass transition temperature of polyarylene sulfide resin and method for producing molded article of polyarylene sulfide resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for lowering Tg of a polyarylene sulfide (PAS) resin. <P>SOLUTION: There are provided the method for lowering the glass transition temperature of the polyarylene sulfide resin by dispersing an anthraquinone compound in the polyarylene sulfide resin phase, and a method for producing a molded article of the polyarylene sulfide resin by melting and kneading the polyarylene sulfide resin composition containing the polyarylene sulfide resin and the anthraquinone compound and molding the kneaded mixture. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for lowering the glass transition temperature of a polyarylene sulfide resin, and to a method for producing a polyarylene sulfide resin molded article having a low glass transition temperature.

Polyarylene sulfide resin (hereinafter sometimes referred to as PAS resin) has excellent heat resistance, chemical resistance, flame retardancy, rigidity, and mechanical properties. As so-called engineering plastics, Widely used in automobile parts, machine parts, structural parts, etc.
A PAS resin generally has a high glass transition temperature (hereinafter sometimes referred to as Tg). For example, in the case of a polyphenylene sulfide resin (hereinafter sometimes referred to as PPS), a differential scanning calorimeter (hereinafter referred to as DSC) may be used. Tg measured by (1) is about 90 ° C. regardless of the molecular weight, cross-linking or non-cross-linking.
Since Tg has a great influence on the mechanical properties and other physical properties of the polymer, the range of use of the polymer can be greatly expanded if it can be controlled arbitrarily and efficiently. For example, since it is known that the adhesion of the polymer to other materials is improved near Tg, if the Tg can be lowered, the adhesive ability near normal temperature can be made higher than that of the conventional PPS resin. In addition, in the case where there is an amorphous (glass) region in the polymer, since the amorphous region becomes rubbery in a temperature region of Tg or higher, elasticity is exhibited. Therefore, if Tg can be significantly lowered, the temperature region indicating the rubber region Can also be lowered, and the possibility of developing a material exhibiting flexibility to the packing member or the like appears.

  As a method for reducing the Tg of the PAS resin, a method is known in which a specific amount of an organic amide compound mainly composed of N-methylpyrrolidone (hereinafter sometimes referred to as NMP) is blended with the PPS resin (see, for example, Patent Document 1). ). However, in this method, the melt kneading temperature of PPS is around 300 ° C. (in Example 1 of Patent Document 1, the cylinder temperature of the kneading apparatus is set to 260-330 ° C.), whereas NMP having a boiling point of 202 ° C. is converted into PPS. Because of the compulsory compounding, the added amount cannot be increased to 2.8% by mass at the maximum, and as a result, even if Tg is the lowest, the reduction is only 73 ° C. and less than 20 ° C. (Example of Patent Document 1) 7) The decrease in Tg is not very high. In addition, as NMP partially volatilizes during the kneading operation, the NMP content is only about 70% of the charged amount in each example, and the addition efficiency is low. The remaining 30% may be volatilized or thermally decomposed to generate voids in the molded product, or may cause lot blurring or deterioration of the working environment due to the odor peculiar to organic amide compounds. Accordingly, there has been a demand for a method that can significantly reduce Tg even by heat treatment at around 300 degrees necessary for melt kneading and molding.

  On the other hand, an anthraquinone known as a coloring material is known to be used for coloring various engineering plastics including PAS resins having a generally high melt kneading temperature. This is partly because the boiling point temperature of anthraquinone is sufficiently high at 380 ° C., and the thermal stability is excellent. For example, Patent Document 2 exemplifies anthraquinone as a colorant for PPS (paragraph 0032). However, these documents have no description except that anthraquinone is used as a colorant.

Japanese Patent Laid-Open No. 10-204293 JP 2008-31393 A

  The subject of this invention is providing the method of reducing Tg of PAS resin.

  The present inventor has found that anthraquinone used as a coloring material and its raw material lowers the glass transition temperature of the PAS resin. It has been found that Tg is lower than that of the PAS molded body that does not.

  That is, the present invention provides a method for lowering the glass transition temperature of a polyarylene sulfide resin in which an anthraquinone compound is dispersed in a polyarylene sulfide resin phase.

  Moreover, this invention provides the manufacturing method of the polyarylene sulfide resin molded object which melt-kneads the polyarylene sulfide resin composition containing a polyarylene sulfide resin and an anthraquinone compound, and is shape | molded.

  Moreover, this invention provides the glass transition temperature reducing agent of polyarylene sulfide resin represented by General formula (1).

（１）

(1)

  According to the present invention, a PAS resin molded product having a low Tg can be obtained.

(Anthraquinone)
The anthraquinone used in the present invention is an anthraquinone that is widely used as a coloring material, and is specifically represented by a structure represented by the following formula (1).

（１）

(1)

(Average particle size)
The average particle diameter of the anthraquinone used in the present invention is within the range that can be obtained, and there is no particular limitation as long as it is in the form of particles that can be easily dry blended with the PAS resin as a pre-stage of melt kneading. This is because the melting point of anthraquinone is 286 ° C., which is lower than the melt kneading temperature of a normal PPS resin (in the case of PPS resin, the melting point is about 280 ° C., and the kneading temperature is higher than 290 ° C. to 320 ° C. In many cases). Therefore, anthraquinone is in a dissolved state in the kneading temperature region of the PPS resin. For this reason, any particle size range of anthraquinone is in a dissolved state in PPS during melt kneading and can be uniformly dispersed.

(PAS resin)
The PAS resin used in the present invention is not particularly limited, and a known PAS resin can be used. Examples thereof include a random copolymer containing a repeating unit having a structure in which an aromatic ring which may have a substituent and a sulfur atom are bonded, a block copolymer, a mixture thereof or a mixture with a homopolymer.
Typical examples of these PAS resins include polyphenylene sulfide (hereinafter referred to as PPS resin). Among the PPS resins, those having a structure in which the bond of the repeating unit to the aromatic ring is in the para position are preferable in terms of heat resistance and crystallinity.

(Binding species)
In addition, the PAS resin has a meta bond, an ether bond, a sulfone bond, a sulfide ketone bond, a biphenyl bond, a phenyl sulfide bond, and a naphthyl bond with an upper limit of less than 10 mol% (however, a component containing a bond having three or more functions is copolymerized). In such a case, the upper limit may be 5 mol%).

(Molecular weight distribution)
The PAS resin used in the present invention preferably has a peak molecular weight of 20,000 or more as determined by gel permeation chromatography using 1-chloronaphthalene as a solvent, and further has a peak molecular weight of 25,000 or more. It is more preferable that In addition, the peak molecular weight in this invention is based on the numerical value calculated | required as a polystyrene conversion amount using a polystyrene as a standard substance in a gel permeation chromatograph measurement. While the number average molecular weight and weight average molecular weight change depending on how the baseline of the molecular weight distribution curve of gel permeation chromatography is taken, the peak molecular weight depends on how the baseline of the molecular weight distribution curve is taken. Is not.

(Melt viscosity)
The melt viscosity of the PAS resin used in the present invention is preferably 100 to 1000 Pa · s, particularly 200 to 500 Pa · s, at 300 ° C. and a shear rate of 500 sec ^{−1 as} measured using a cavity rheometer. It is preferable that it is s. When the melt viscosity is within this range, the dispersion of the phthalocyanine used in the present invention is good and the function as a nucleating agent is exhibited well.

(Method for producing PAS resin)
The method for producing the PAS resin is not particularly limited. For example, 1) a method in which a dihalogenoaromatic compound and, if necessary, other copolymerization components are polymerized in the presence of sulfur and sodium carbonate, 2) a dihalogenoaromatic A method of polymerizing a group compound and, if necessary, other copolymerization components in a polar solvent in the presence of a sulfidizing agent or the like, 3) p-chlorothiophenol and, if necessary, other copolymerization 4) a method in which a component is self-condensed, and 4) a method in which a sulfidizing agent, a dihalogenoaromatic compound and, if necessary, another copolymer component are reacted in an organic polar solvent.
Among these methods, the method 4) is versatile and preferable. In the reaction, an alkali metal salt of carboxylic acid or sulfonic acid or an alkali hydroxide may be added to adjust the degree of polymerization.
Among the methods 4), a hydrous sulfiding agent is introduced into a mixture containing a heated organic polar solvent and a dihalogenoaromatic compound at a rate at which water can be removed from the reaction mixture, and the dihalogenoaromatic compound and A method for producing a PAS resin by reacting with a sulfidizing agent and controlling the amount of water in the reaction system in the range of 0.02 to 0.5 mol relative to 1 mol of the organic polar solvent (for example, Those obtained by Kaihei 07-228699 are particularly preferred.

(Method for adjusting PAS resin composition)
The PAS composition of the present invention is obtained by dispersing the anthraquinone in the PAS resin. The dispersion method is not particularly limited. For example, the PAS resin powder and the anthraquinone are uniformly dry-blended with a mixer such as a tumbler or Henschel mixer, and then melt-kneaded with a uniaxial or biaxial extruder to form ( The method is generally granulated) to obtain pellets. The melt kneading temperature at this time is not particularly limited, and can be exemplified by a range of 290 to 360 ° C. higher than the melting point of the PAS resin and lower than the decomposition temperature. Since anthraquinone has a melting point of 286 ° C. and a boiling point of 380 ° C., anthraquinone is in a liquid state in the same temperature range as PPS. Accordingly, since dispersion at the molecular level becomes possible, Tg can be efficiently reduced.

(Content of anthraquinone in PAS resin composition)
The effect of lowering the Tg of anthraquinone increases according to the blending amount in the PAS resin, and it is possible to lower Tg by 30 ° C. (DSC measurement) by dispersing 30% by mass. (Refer to FIG. 1) On the other hand, even when an amount exceeding 40% by mass is added, there is almost no change in the Tg, and the rate of loss due to sublimation of anthraquinone itself tends to increase. It is preferable to disperse 3 to 40% by mass of anthraquinone with respect to 100. Even if it is less than 3% by mass, there is an effect of reducing Tg, but the effect is small.

(Reason for lowering Tg)
The reason why anthraquinone lowers the Tg of the PAS resin is not clear, but it is presumed that the anthraquinone skeleton has high planarity, that anthraquinone and the PAS resin interact with each other through a π bond, or anthraquinone and the PAS resin. It is presumed that this is due to the fact that it has a close melting point and is close to complete compatibility.
For example, a PPS molecule is known to have an α-helix structure (spiral type) structure in a crystalline state, anthraquinone enters in a molecular state between the helical structures, and the planar structure of anthraquinone is a PPS molecule. It is presumed to inhibit intermolecular binding. It is also presumed that anthraquinone, which is a low molecule, caused molecular vibrations upon heating, which also led to a decrease in Tg.

(Other ingredients)
In the present invention, various additives may be added for the purpose of improving the mechanical characteristics and improving the molding processability within a range not impairing the object of the present invention.

(Additive-1: Inorganic filler)
In the present invention, an inorganic filler can be used in combination for the purpose of improving the elastic modulus of the PAS resin composition. Specific examples include glass fiber, carbon fiber, carbon black, activated carbon, calcium titanate, potassium titanate, silicon carbide, aramid fiber, ceramic fiber, metal fiber, silicon nitride, barium sulfate, calcium sulfate, kaolin, clay, bentonite, Sericite, zeolite, mica, mica, talc, wollastonite, PMF, ferrite, aluminum silicate, calcium silicate, calcium carbonate, dolomite, magnesium oxide, magnesium hydroxide, antimony trioxide, titanium oxide, iron oxide, milled glass, There are glass beads, glass balloons, and various simple metal particles. Of these inorganic fillers, compounds having a nucleating effect such as clay and talc may be used in combination, but when it is desired to preferentially develop the nucleating effect of phthalocyanine, it is used in an amount smaller than the amount of phthalocyanine. It is preferable.

(Additive-2: Thermoplastic elastomer)
A thermoplastic elastomer may be used in combination in order to impart elongation properties to the PAS resin composition used in the present invention. The amount of these elastomers is preferably 20% by mass or less in the composition, and a particularly preferred range is 10% by mass or less.

(Method for producing PAS resin molding)
The PAS resin composition of the present invention can be preferably used as a molded article. The PAS resin molded body includes, for example, step 1 (corresponding to the above (method for adjusting the PAS resin composition)) of melt-kneading a polyarylene sulfide resin composition containing a polyarylene sulfide resin and anthraquinone, and the melt-kneading. It can be obtained by the step 2 of molding the melt-kneaded product obtained by the above process.
There is no limitation in particular in the shaping | molding method in process 2, In addition to setting it as the said pellet (granulation), it can also process into a desired shape with a shaping | molding machine. Specific examples include injection molding and press working. It can be set as a desired member by processing by these methods. Usually, the pellet is formed by a molding machine or the like. As these processing methods, known and commonly used methods are used.
Further, the mold temperature is usually 150 ° C. to 200 ° C. in many cases.

  If necessary, a cooling step is provided, but if it is desired to be amorphized, it is preferably water-cooled for rapid cooling. On the other hand, if it is desired to crystallize, the molded product is removed from the mold after solidification and air-cooled. For example, a method of leaving the mold at a temperature at which solidification occurs in the mold for a certain period of time, a method of lowering the mold temperature after molding and cooling in the mold can be exemplified.

  The following examples further illustrate the present invention. The present invention is not limited to the scope of these examples.

Example 1 Method for Producing PAS Resin Molded Body
Example 1 in Table 1 using powder of “PPS resin (product number MA-520; manufactured by DIC Corporation; peak molecular weight 45,000, linear type)” as anthraquinone and PAS resin so that the total amount becomes 5.00 g. After uniformly dry blending at a blending ratio of 1 (equivalent to 5% by mass of anthraquinone), kneading temperature is 300 ° C., rotation speed is 300 rpm, and the mixture is melted for 10 minutes using a resin melt kneading apparatus Laboplast Mill KF-6V (manufactured by Toyo Seiki Co., Ltd.) A PAS resin composition was obtained by kneading.
Then, the amorphous sheet | seat (1) was obtained by pressing at 300 degreeC using the sheet | seat type | mold with a thickness of 200 micrometers, and water-cooling. The obtained amorphous was a transparent sheet having a light red color, and anthraquinone aggregates were not seen, and the mixture was a uniform kneaded product.

The obtained amorphous sheet (1) was evaluated by the following method.
(Dynamic viscoelasticity (DMA))
RSAIII (manufactured by TA Instruments) is used as a dynamic viscoelasticity measuring device, and temperature ranges: 0 ° C. to 260 ° C., heating rate 5 ° C./min, applied frequency 1 Hz, distance between cages 25 mm, load Measurement was performed under the condition of 0.05% strain, and the dynamic viscoelastic behavior was measured. The sample used was an amorphous sheet (1) cut into 45 mm × 6 mm strips. From the dynamic viscoelasticity obtained, the peak temperature of tan δ was defined as Tg.

(Differential thermal analysis (DSC))
Using Pyris Diamond DSC (manufactured by Perkin Elmer Co., Ltd.), the measurement was performed under the temperature range of 0 ° C. to 320 ° C. and the heating rate of 10 ° C./min, and Tg was measured. The sample was used by punching the amorphous sheet (1) into a 6 mm diameter and putting it in an aluminum pan.

(Examples 2 to 6: Change of anthraquinone ratio 10 to 40% by mass)
Amorphous sheet-like PAS resin moldings (2) to (6) were obtained in the same manner as in Example 1 except that the amount of PAS resin to be used and the amount of anthraquinone were changed to those shown in Table 1. The blending ratios and evaluation results are shown in Table 1.

(Comparative Example 1; no anthraquinone)
Using 5.00 g of only the PAS resin, a sheet-like PAS resin molded body made amorphous was obtained in the same manner as in Example 1. The evaluation results are shown in Table 1.

In the table, “actual” is an abbreviation for the example, and “ratio” is an abbreviation for the comparative example. Details of the material of the symbol are as follows.
PAS resin: PPS resin (product number MA-520; manufactured by DIC Corporation; peak molecular weight 45,000, linear type)
Anthraquinone: Reagent manufactured by Kanto Chemical Co., Inc., purity 95.0% or more

  The graph of the change behavior of Tg in DSC in the amorphous sheet Examples 1 to 6 obtained in Examples and the comparative example not containing anthraquinone is shown in FIG.

  As a result, by dispersing anthraquinone in the PAS resin by melt-kneading, the amount of change in the Tg of the PAS resin could be greatly reduced to 36 ° C. for DMA measurement and 30 ° C. for DSC measurement.

It is a graph of the change behavior of Tg in DSC of the amorphous sheet | seats (1)-(6) obtained in the Example, and the sheet | seat obtained by the comparative example.

Claims (4)

A method for lowering the glass transition temperature of a polyarylene sulfide resin, comprising dispersing an anthraquinone compound in the polyarylene sulfide resin phase. The method for lowering the glass transition temperature of the polyarylene sulfide resin according to claim 1, wherein 3 to 40% by mass of the anthraquinone compound is dispersed. A method for producing a polyarylene sulfide resin molded article, comprising melting and kneading a polyarylene sulfide resin composition containing a polyarylene sulfide resin and an anthraquinone compound, and then molding the resulting mixture. A polyarylene sulfide resin glass transition temperature reducing agent represented by the general formula (1).

(1)

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