JPH0762240A - Molding material of polyarylene sulfide resin for powder molding - Google Patents

Abstract

PURPOSE:To obtain the subject molding material useful for hollow molded articles, tubular molded articles, etc., having improved appearance and thickness precision, excellent appearance of molded article, comprising polyarylene sulfide resin powder having a specific particle size distribution. CONSTITUTION:This molding material comprises polyarylene sulfide resin (preferably polyphenylene sulfide resin) powder, containing >=70mol% of a repeating unit of the formula [-phi-s-] (phi is p-phenylene), having a particle size distribution composed of (A) 30-70wt.% of particles not passing through a wire cloth of 32 mesh, (B) 20-60wt.% of particles passing through a wire cloth of 100 mesh and (C) <30wt.% of particles passing through a wire cloth of 32 mesh and not passing through a wire cloth of 100 mesh, having <=1,000ppm Na content.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyarylene sulfide resin molding material for powder molding.
It is possible to obtain a hollow molded product with good wall thickness accuracy.

[0002]

2. Description of the Related Art Polyphenylene sulfide (hereinafter referred to as PP
Polyarylene sulfide (hereinafter abbreviated as PAS) resins represented by S) have excellent heat resistance and chemical resistance in themselves, and among them, molding materials reinforced with a reinforcing material such as glass fiber are , Is being used as a metal substitute in the fields of automobile parts and electronics-related parts,
In recent years, demand has greatly increased.

When a hollow molded article is obtained by powder molding, the particle size of the resin molding material used is 32 mesh pass particles (particles having a particle size that passes through a 32 mesh wire net) to 100 mesh on (32 mesh wire net). It is general to use a powder having a particle size distribution composed of particles having a particle size which does not pass through. The same applies to the case where a hollow molded product made of PPS resin is obtained by powder molding.
Powder molding is performed using a PPS resin having a particle size distribution such that 80% by weight or more is contained in 100 mesh (JP-A-4-26).
7113). However, even if the PPS resin powder having such a particle size distribution is used, bubbles may remain on the surface of the molded product that is in contact with the mold, resulting in a poor appearance, and uneven thickness. The current situation is that there are problems.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have aimed to obtain a molded product made of PAS resin by a powder molding method, which has a good appearance and a uniform wall thickness. .

[0005]

The inventors of the present invention used a PAS resin powder having a very specific particle size distribution for powder molding, and thus, the appearance of the molded product was excellent and the thickness uniformity was excellent. It was found that a molded product was obtained, and the present invention was achieved.

That is, according to the present invention, (1) 30 to 70% by weight of particles that do not pass through a 32 mesh wire mesh, (2) 100
Polyarylene sulfide resin powder having a particle size distribution in which particles that pass through a mesh wire mesh are 20 to 60% by weight, and (3) particles that pass through a 32 mesh wire mesh and particles that do not pass through a 100 mesh wire mesh are less than 30% by weight. The present invention relates to a polyarylene sulfide resin molding material for powder molding, which is a body.

The PAS resin as the base material in the present invention is
A polymer containing a repeating unit represented by the general formula [-Ar-S-] (wherein -Ar- represents a divalent aromatic group containing at least one 6-membered carbon ring) in an amount of 70 mol% or more. so,
The representative substance is represented by the general formula [-φ-S-] (however, -φ-
Is a polymer containing 70 mol% or more of the repeating unit represented by p-phenylene group).

A PAS resin such as a PPS resin is generally a substantially linear PPS (for example, Japanese Examined Patent Publication No. Sho 6) by its manufacturing method.
3-33775), a PPS having a branched structure using a trifunctional monomer (for example, Japanese Patent Publication No. 54-8719), and a PPS having a crosslinked structure thermally crosslinked by heat treatment are known. In the invention, both types are effective.

The preferred PAS resin for use in the present invention is the repeating unit [-φ-S-] (provided that -φ
Is a PPS resin containing 70 mol% or more of (indicating p-phenylene group). When this repeating unit is 70 mol% or more, sufficient strength, which is a characteristic of a crystalline polymer, is obtained, and toughness and chemical resistance are excellent.

Other copolymerizable structural units that may be contained in the PPS resin include, for example,

[0011]

[Chemical 1]

[0012]

[Chemical 2]

[0013]

[Chemical 3]

[0014]

[Chemical 4]

[0015]

[Chemical 5]

[0016]

[Chemical 6]

And the like. Of these, the trifunctional unit is 1
It is also preferable that the content is mol% or less from the viewpoint of not lowering the crystallinity.

In the PAS resin powder of the present invention, as described above, (1) 30 to 70% by weight of particles that do not pass through the 32 mesh wire net, and (2) 20 to 60% by weight of particles that pass through the 100 mesh wire net. %, And (3) less than 30% by weight of particles that pass through a 32 mesh wire mesh and do not pass through a 100 mesh wire mesh. More preferably (1) 100% by weight of 5 mesh wire mesh passes, but 40 to 70% by weight of particles that pass through 5 mesh wire mesh but not 32 mesh wire mesh, and (2) pass through 100 mesh wire mesh. 20-50% by weight of particles, (3) 3
It has a particle size distribution in which particles passing through a 2-mesh wire net and not passing through a 100-mesh wire net are less than 20% by weight. That is, unlike the conventional one having a grain size having a peak between 32 and 100 mesh, it is characterized by having grain size peaks at two locations of 32 mesh or less and 100 mesh or more. When the particle size distribution of the PAS resin is within the range of the present invention as described above, the accuracy of the wall thickness of the molded product is good, and the appearance of the PAS is good with no bubbles on the surface of the molded product.
A resin powder molding is obtained.

The PAS resin powder having such a particle size distribution is obtained by sizing the PAS resin powder obtained during PAS polymerization,
You may use the thing of the range of this particle size distribution. Further, any PAS resin obtained by various polymerization methods is pelletized using an extruder and then pulverized by a freeze pulverization method or the like.
Alternatively, the PAS resin powder may be subjected to a treatment such as granulation to obtain a desired particle size distribution. Alternatively, two or more kinds of PAS resin after polymerization or PAS resin subjected to the treatment may be used, and these may be mixed so as to be within the range of the particle size distribution.

After polymerization, pulverization treatment or the like is performed to obtain two or more kinds of PAS resins having different particle size distributions, and then these are mixed to obtain a PAS resin powder having a particle size distribution range of the present invention. The following is an example of mixing the PAS resin. For example, a relatively large particle size PAS resin powder (A) having a particle size distribution in which 50% by weight or more of particles that do not pass through a 32 mesh wire mesh and less than 10% by weight of particles that pass through 100 mesh and 10 mesh There is a method of mixing with PAS resin powder (B) having a relatively small particle size having a particle size distribution in which 100% by weight of the particles pass through the wire mesh and 90% by weight or more of the particles pass through the 100 mesh. More preferably, PAS resin powder (A) having a particle size distribution in which 100% by weight of a 5-mesh wire mesh but 60% by weight or more of particles not passing through 32 mesh and less than 5% by weight of particles passing through 100 mesh are used. ) And 2
100% by weight of particles passing through a 0 mesh wire mesh is 10
Particles passing through 0 mesh may be mixed with the PAS resin powder (B) having a particle size distribution of 95% by weight or more.

When two kinds of PAS resins such as the PAS resin (A) and the PAS resin (B) are blended, what is the mixing ratio so long as it falls within the above-mentioned particle size distribution of the present invention? The ratio may be 5 to 95% by weight of the PAS resin (A) and 5 to 95% by weight of the PAS resin (B).
There is a mixing ratio consisting of weight%.

As the PAS resin used in the present invention, a PAS resin having the above-mentioned particle size distribution is a sufficiently good PA.
Although a powder molded product made of S resin is obtained, the melt viscosity of the PAS resin is 800 to 20000 poise, preferably 1000 to 15000 poise, more preferably 3000 to 8000 poise (measurement temperature: 315.
6 ° C, shear rate: 10 sec ^-1 , orifice L / D = 1
0 / 1mm, measuring machine: capillary type melt viscosity measuring machine)
Those within the range are preferably used. Melt viscosity is 2
If it exceeds 0000 poise, bubbles are likely to remain on the appearance of the molded product, and if it is less than 800 poise, the impact resistance of the molded product is poor and there is a practical problem.

When the PAS resin powder charged into the molding die is a crushed PAS resin powder, such a resin powder has a melting point of the PAS resin of 100 ° C. or higher (measured by a differential scanning calorimeter). Heat treatment at a temperature equal to or lower than the melting point). Particularly, the heat treatment is performed at 100 ° C or higher under stirring.
It is preferable to perform the treatment at a temperature not higher than the melting point of AS, preferably 120 ° C. or higher and 250 ° C. or lower for 5 minutes or longer. Such heat treatment,
Particularly, by performing heat treatment with stirring, it is possible to obtain a rotomolded product having an excellent appearance of the molded product.

Furthermore, in the present invention, the PA used
S resin, such as PPS resin, has a sodium content of 100.
If it is 0 ppm or less, preferably 500 ppm or less,
A molded article having excellent elution characteristics (for example, in ultrapure water) can be obtained. PA with a sodium content of 1000 ppm or less
To obtain the S resin, treatments such as acid treatment, hot water treatment, organic solvent washing and the like can be mentioned. Known methods can be used as these methods. For example, the hot water treatment method described in JP-A-62-153344 and the organic solvent method described in JP-A-64-26670 can be mentioned, but the method is not limited to these.

The method of powder molding in the present invention is publicly known (Plastic Processing Technology Handbook, edited by Nikkan Kogyo Shimbun, published in 1969, molding, Volume 4, No. 3, P146 1
992) and the like, and there are a stationary method, a rotation method, a rotation shaking method, and the like. Among these, the present invention is particularly applicable to the rotational molding method,
Although it is effective for the rotational vibration method, the present invention does not particularly define these molding methods and molding conditions. Specifically, the powdery PPS resin is put in a closed mold set to a temperature equal to or lower than the melting point of the PPS resin, and the melting point of the PPS resin is 450 ° C, preferably 290 to 380 ° C in the horizontal and vertical directions. While applying uniaxial or simultaneous biaxial rotation, the powder particles are adhered to the inner wall surface of the mold in a uniform layer, and melted and sintered to form a uniform continuous melt layer. At this time, if necessary, an inert gas (nitrogen, helium, argon, carbon dioxide) atmosphere is used. Next, the mold is cooled while rotating to solidify the resin layer, and then the mold is opened and the molded product is taken out.

If desired, the composition of the present invention may contain the following reinforcing materials and / or fillers. As these reinforcing materials and / or fillers,
Examples thereof include powdery grains, flat plates, scales, needles, spheres or hollows, and fibers. Specifically, calcium sulfate, calcium silicate, clay, talc, alumina, silica sand, glass powder, metal powder, graphite, silicon carbide, silicon nitride,
Powder / granular filler such as silica, boron nitride, aluminum nitride, carbon black, mica, glass plate, metal foil such as sericite, aluminum flake, flat plate-like or scale-like filler such as graphite, shirasu balloon, metal balloon Hollow fillers such as glass balloons, glass fibers,
Carbon fiber, graphite fiber, whiskers, metal fiber,
Organic fibrous fillers such as asbestos, wosnite, fibrous fillers and aromatic polyamide fibers can be mentioned.

Other thermoplastic resins may be added to the PAS resin of the present invention. Other thermoplastic resins include polyethylene, polypropylene, polystyrene, imide-modified polystyrene, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyamide, polycarbonate, ABS resin. , Imide-modified ABS resin, AES resin,
Polysulfone, polyphenylene ether, copolymer and / or mixture of polyphenylene ether and polystyrene, thermoplastic resin such as polyethersulfone, polysulfide ketone, polysulfide sulfone, polyether ether ketone, polyamideimide, polyester system, Examples include thermoplastic elastomers such as polyamide type, polyurethane type, polyolefin type and polystyrene type. Further, ethylene-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate-acrylate copolymer, ethylene-maleic anhydride-acrylate copolymer, preferably ethylene-glycidyl methacrylate copolymer, polypropylene, polybutylene terephthalate, polyamide , Polyphenylene ether, copolymers and / or mixtures of polyphenylene ether and polystyrene.

In the present invention, an inorganic flame retardant such as magnesium hydroxide, aluminum hydroxide and antimony trioxide, an organic flame retardant such as a halogen type and a phosphorus type, and an antioxidant within the scope of the present invention. Additives such as a UV inhibitor, a lubricant, a dispersant, a coupling agent, a foaming agent, a cross-linking agent, and a coloring agent can be added.

As a method for mixing these thermoplastic resins and various additives, a PAS resin, another thermoplastic resin, and an additive compounded at a predetermined mixing ratio are used in a single-screw extruder, a twin-screw extruder, It is preferable that the mixture is heated and melt-mixed with a mixer such as a Banbury mixer, and the pelletized product is pulverized by a method such as freeze pulverization and then used as a molding material for powder molding.

When a filler or a reinforcing material is used, the above-mentioned method may be used or the PAS resin powder may be directly mixed and used as a powder molding material.

[0031]

EXAMPLES The present invention will be further described below with reference to examples.
FIG. 1 shows a schematic diagram of an experimental apparatus used in Examples and Comparative Examples of the present invention. As shown in the schematic diagram of FIG. 1, 50 g of a material containing PPS resin powder as a main component is put in a cylindrical mold 1 (diameter 7 cm) of a rotary molding apparatus, and nitrogen is supplied to expel air to remove nitrogen. Put in an atmosphere. The mold 1 is supported by a rotating shaft 2 and is horizontally rotated by a motor 3. The mold 1 is placed in the heating furnace 4 after the materials are put therein. The heating furnace 4 is previously held below the melting point of the PPS resin. After installing the mold 1 containing the material in the heating furnace 4,
The heating furnace 4 is heated to a predetermined temperature equal to or higher than the melting point of the PPS resin, and after reaching the predetermined temperature, left for a predetermined time. Then, the heating furnace 4 is air-cooled to 200 ° C. The mold 1 is taken out of the heating furnace 4, cooled with water and cooled to room temperature, and then the molded product is taken out.

Evaluation of Molded Product (1) Thickness Unevenness of Molded Product The difference between the maximum value and the minimum value of the thickness of the molded product was measured.

(2) Appearance of molded product Evaluation was made based on the presence or absence of air bubbles on the surface of the molded product which is in contact with the mold.

Measurement of Melt Viscosity A sample of about 15 g was dried at 120 ° C. for 3 hours, and then a capillary type melt viscosity set to a predetermined temperature (315.6 ° C.) using an orifice having a diameter of 1.0 mm and a length of 10 mm. It is put into a measuring machine (manufactured by Toyo Seiki), air bubbles are removed, and after preheating for 5 minutes, shear rate is changed and measurement is performed.

Measurement of sodium (Na) content The polymer is decomposed with sulfuric acid and then measured by an atomic absorption method.

In the following examples, the mesh passes when the powder passes through the mesh used for the measurement, and the mesh is on when the powder does not pass.

Examples 1 to 4, Comparative Examples 1 to 4 PP having a resin type and a particle size distribution as shown in Table-1.
After preparing S resin powder and drying at 150 ° C / 2 hours, 2
Put 50g of material into a mold that has been preheated in a heating furnace set at 30 ° C, and rotate while rotating at 60rpm.
The temperature was raised to 30 ° C. in about 6 minutes, and the mixture was left standing while rotating at 330 ° C. for 5 minutes. Next, it was cooled to 180 ° C. in about 10 minutes, the mold was taken out, and after cooling with water, the molded product was taken out, and the thickness of the molded product and the appearance of the molded product (existence of bubbles on the surface in contact with the mold) were examined. . As is apparent from the results, the present invention has an excellent appearance of the molded product and has little thickness unevenness.

[0038]

[Table 1] Resin type L: Linear PPS (melt viscosity 5000 poise, Na content 150
ppm) B: Branched-type PPS (melt viscosity 5000 poise, Na content 1
75ppm) C: Heat-crosslinking type PPS (melt viscosity 5,000 poise, Na content
250ppm)

Reference Example 1 A substantially linear PPS resin having a particle size distribution shown in Table 2 and a melt viscosity of 1500 poise, a Na content of 215 ppm and a melting point of 281 ° C. (hereinafter referred to as PPS (B-1)). )
Was melt-kneaded at 300 ° C. using a twin-screw extruder, and the pelletized product was freeze-pulverized to obtain a PPS resin powder having a particle size distribution as shown in Table-2. This is PPS (A
-1).

Reference Example 2 A cross-linked PPS resin (hereinafter referred to as PPS (B-2)) having a particle size distribution shown in Table 2 and a melt viscosity of 7,000 poise, a Na content of 250 ppm and a melting point of 282 ° C. is used as a reference example. The pelletized product was frozen and pulverized in the same manner as in 1 to obtain a PPS resin powder. This is designated as PPS (A-2).

Reference Example 3 A branched PPS resin (hereinafter referred to as PPS (B-3)) having a particle size distribution shown in Table 2 and a melt viscosity of 6000 poise, a sodium content of 513 ppm and a melting point of 278 ° C. was used. Thereafter, a PPS resin powder was obtained in the same manner as in Reference Example 1. This is designated as PPS (A-3).

Reference Example 4 Crosslinked PPS resin PPS (B-
Using 2) a powder granulator, a granular PPS resin was obtained. This is designated as PPS (A-4).

Reference Example 5 The PPS resin pellet used in Reference Example 2 was freeze-pulverized to obtain a PPS resin powder (hereinafter referred to as PPS (C-1)).
Got

Table 2 below shows the particle size distribution of each PPS resin powder obtained in the above reference example.

[0045]

[Table 2]

Examples 5 to 8 and Comparative Examples 5 to 11 The PPS resin powders shown in Table 2 above were used as the PPS resin (A) and PPS resin (B), and the compounding ratios shown in Table 3 were used. The ingredients were blended and dried at 150 ° C. for 2 hours. Next, 50 g of the material was put into a mold that had been heated in advance in a heating furnace set at 230 ° C., the temperature was raised to 330 ° C. in about 6 minutes while rotating at 60 rpm, and the mixture was left standing while rotating at 330 ° C. for 5 minutes. Next, it was cooled to 180 ° C. in about 10 minutes, the mold was taken out, and after cooling with water, the molded product was taken out, and the thickness of the molded product and the appearance of the molded product (existence of bubbles on the surface in contact with the mold) were examined. . As is apparent from the results, the present invention has an excellent appearance of the molded product and has little thickness unevenness.

[0047]

[Table 3]

Examples 9 to 10 and Comparative Examples 12 to 13 PPS (A-4) and PPS (B) as PPS resin powders
-2) was used and blended at a blending ratio shown in Table-4, and 150
Dry for 2 hours. Next, add 50 g of the material to a mold that has been heated in advance in a heating furnace set to 230 ° C.,
The temperature was raised to 330 ° C. in about 6 minutes while rotating at 60 rpm, and left standing while rotating at 330 ° C. for 5 minutes. Then cool to 180 ° C in about 10 minutes, remove the mold,
After cooling with water, the molded product was taken out, and the thickness of the molded product and the appearance of the molded product (existence of bubbles on the surface in contact with the mold) were examined.
As is apparent from the results, the present invention has an excellent appearance of the molded product and has little thickness unevenness.

[0049]

[Table 4]

Examples 11 to 12 and Comparative Example 14 PPS (A-4) and PPS (B- as PPS resin powder
2) and PPS (C-1) were used at the compounding ratio shown in Table 5 and dried at 150 ° C. for 2 hours. 230 ° C
Material that has been preheated in the heating furnace set to
Add 50g and rotate at 60rpm, 330 ℃
The temperature was raised to about 6 minutes, and the mixture was left standing while rotating at 330 ° C. for 5 minutes. Then cool to 180 ° C in about 10 minutes,
After taking out the mold and cooling with water, the molded product was taken out, and the thickness of the molded product and the appearance of the molded product (presence of bubbles on the surface in contact with the mold) were examined. As is apparent from the results, the present invention has an excellent appearance of the molded product and has little thickness unevenness.

[0051]

[Table 5]

Examples 13 to 14 Crosslinked PPS resin powder used in Example 3 (5 mesh pass 32 mesh on: 63 wt%, 32 mesh pass 100 mesh on: 6 wt%, 100 mesh pass:
31% by weight), the mixture was heat-treated with stirring under the conditions shown in Table 6, dried at 150 ° C. for 2 hours, and then rotationally molded in the same manner as in Example 3.

The results are shown in Table-6. The present invention is excellent in the appearance of the molded product and has little thickness unevenness.

[0054]

[Table 6]

[0055]

INDUSTRIAL APPLICABILITY The PAS resin molding material for powder molding of the present invention is a PAS resin powder having a specific particle size distribution, which makes it possible to obtain a PA with excellent thickness accuracy and appearance of the molded product.
A powder molded product made of S resin can be obtained. Therefore, the PAS resin molding material of the present invention is a hollow molding product, a tubular molding product,
It is extremely useful as a molding material for powder molding for molding various containers and the like.

[Brief description of drawings]

FIG. 1 is a schematic view of a rotary molding apparatus which is one of powder molding apparatuses.

[Explanation of symbols]

 1 Cylindrical mold 2 Rotating shaft 3 Motor 4 Heating furnace

Claims (8)

[Claims] (1) 30 to 70% by weight of particles not passing through a 32 mesh wire mesh, (2) 20 to 60% by weight of particles passing through a 100 mesh wire mesh, and (3) a 32 mesh wire mesh. A polyarylene sulfide resin molding material for powder molding, which is a polyarylene sulfide resin powder having a particle size distribution in which particles that pass through and do not pass through a 100 mesh wire mesh are less than 30% by weight. 2. The molding material according to claim 1, wherein the polyarylene sulfide resin is substantially linear, branched, or heat-crosslinkable, or a mixture of one or more thereof. 3. The molding material according to claim 1, which is a polyarylene sulfide resin having a sodium content of 1000 ppm or less. 4. The polyarylene sulfide resin is a polyphenylene sulfide resin.
The molding material described. 5. The molding material according to claim 4, wherein the melt viscosity is 800 to 20000 poise under the conditions of 315.6 ° C. and a shear rate of 10 sec ⁻¹ . 6. The molding material according to claim 1, wherein a pulverized polyarylene sulfide resin powder is used. 7. The molding material according to claim 6, wherein the pulverized resin powder is heat-treated at a temperature of 100 ° C. or higher and lower than the melting point of the polyarylene sulfide resin before use. 8. The molding material according to claim 7, which is heat-treated with stirring.