JPH0397757A - Polyphenylene sulfide resin composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a polyphenylene sulfide resin with excellent moldability, and more specifically, polyphenylene sulfide containing a specific amount of polybrobylene as a mold release agent. By incorporating this, the ability to release the molded product from the mold (mold releasability) during injection molding processing is dramatically improved regardless of whether the mold temperature is high or low, and the molding processing time is shortened. This invention relates to a polyphenylene sulfide resin sole that achieves this.

"Conventional Conventional" Polyphenylene sulfide resin (hereinafter abbreviated as PPS) has high heat resistance, chemical resistance, dimensional stability, and flame retardancy. Furthermore, it is known that advanced mechanical properties can be exhibited by incorporating reinforcing materials such as glass fiber and carbon fiber, or inorganic fillers such as calcium carbonate and mica. It is widely used in functional mechanical parts, mainly automotive electrical parts.

These parts of PPS are mainly produced by a processing method called injection molding. The biggest advantage of injection molding is
The advantage is that it is possible to produce extremely large quantities of articles of the same shape within a short period of time. The cycle of injection molding is: ■ injection time (time for filling the mold with molten resin + time for solidifying the resin), ■ cooling time (after solidifying in the mold, ■ rigidity to withstand the mold release process),
(time required to obtain strength); and (2) release time (time required to open the mold and take out the molded product using an ejector, etc.).

However, PPS resin is generally said to have poor mold release properties. There are various possible reasons for this, but the main ones include: 1. High adhesion to metal; 2. Relatively small shrinkage rate. Furthermore, as an important factor specific to PPS, the mold releasability is greatly affected by the temperature of the mold, especially at mold temperatures below 120°C, especially around 90°C, which is the glass transition point, the mold release does not occur at all. ．． Due to these shortcomings, when molding PPS resin, sufficient cooling time is required for the resin to shrink sufficiently and become strong and rigid enough to withstand high ejection force (mold release resistance). As a result, PPS is recognized as an engineering plastic with poor mold releasability and a relatively long molding cycle.

As mentioned above, the PPS resin itself has a serious drawback in mold processing, such as poor mold releasability due to the characteristics of high adhesion with the mold and low mold shrinkage rate.

As a measure to improve this defect in mold releasability, the mold cavity is sprayed with silicone oil (D', i).
A small amount of zinc stearate, etc. attached to the surface of a PPS resin pellet is expected to act as an external mold release agent, PP
Measures have been taken to add a small amount of silicone oil, polytetrafluoroethylene resin powder, etc. during the production of S resin pellets, aiming to act as an internal mold release agent.

However, while spraying silicone oil into the cavity as a measure against the above-mentioned mold release property has an extremely excellent mold release effect, it is necessary to perform spraying once or more every few shots. In addition, if there is a weld part in the precept item,
Silicone oil collects in the weld area and doubles the decline in weld strength, which is a weak point of PPS. Furthermore, when electrical or electronic parts are used in the product, a number of disadvantages have been pointed out, such as the risk of electrical contact failure due to adhering silicone oil. Furthermore, the external addition of metal soaps such as zinc stearate does not have much of an effect on improving mold release for PPS resins. Furthermore, although silicone oil, polytetrafluoroethylene resin powder, and the like can be expected to have some effect as internal mold release agents, silicone oil has the disadvantage of electrical contact failure as described above. Furthermore, polytetrafluoroethylene resin powder has the disadvantage that it does not have the effect of improving mold release unless it is added in large amounts to the PPS resin. ``Problems to be Solved by the Invention'' An object of the present invention is to provide a PPS composition having improved mold release properties compared to the above-mentioned conventional PPS composition. "A Thousand Steps to Solving the Problem" As a result of intensive research, the inventors discovered that by adding a small amount of polypropylene to PPS, they were able to improve the mold releasability in the injection and molding process, which is a major drawback of PPS. I discovered that it is possible to master the precepts. This degree of improvement in mold release property is not only superior in that a molded product can be obtained from the cavity with an extremely small mold release force of 1 to 10 or less compared to the case without polypropylene; It has been found that, compared to the case where an additive with a mold release effect is included, a superior mold release effect can be obtained in an extremely wide mold temperature range of 60 to 180°C.

That is, the present invention basically avoids adding polypropylene to PPS as a mold release agent, and if necessary, adds heat resistance, strength, and rigidity as engineering plastics to PPS containing polypropylene. A reinforced PPS can be obtained by adding a fibrous reinforcing agent, preferably glass fiber, carbon fiber, and/or various inorganic fillers such as calcium carbonate, talc, miryoku, and glass beads to the resin composition. We provide resin-made products.

In the present invention, the polypropylene used is D
According to IN standard DIN53018, the melt viscosity at 180°C is 5000mPa. A compound having a relatively low molecular weight of S or less is used. If its melt viscosity is high, PI
'Dispersion in S is not uniform, making it difficult to obtain good mold release characteristics.

The polypropylene is composed of a propylene homopolymer or a random or block copolymer of polypropylene and other olefins such as ethylene and butene.

Furthermore, the shapes of polybrobylene include powder, granules,
Both bead and granule forms can be used, but powder and granule forms are preferred in consideration of dispersion in PPS.

The amount of polypropylene to be added to PPS is preferably 0.000 to PPSIOO parts by weight. 1-6
Parts by weight, more preferably 0. It is 2 to 3 parts by weight. If the amount added is within this range, the mold release effect will be better and the mechanical performance will not deteriorate much.

Those containing 90 mol % or more of the structural unit represented by the formula are preferable; if the amount is less than 90 mol %, it is difficult to obtain a compound with excellent properties. Polymerization methods for this polymer include a method in which P-dichlorobenzene is polymerized in the presence of sulfur and sodium carbonate, a method in which P-dichlorobenzene is polymerized in the presence of sulfur and sodium carbonate, and a method in which P-dichlorobenzene is polymerized in the presence of sodium sulfide, sodium bisulfide and sodium hydroxide, or hydrogen sulfide and sodium hydroxide in a polar solvent. Examples include self-condensation of P-chlorothiophenol, and polymerization of sodium sulfide and P-dichlorobenzene in an aqueous solvent such as N-methylpyrrolidone or dimethylacetamide or a sulfonic solvent such as sulfolane. A method of reaction is suitable. At this time, in order to adjust the degree of polymerization, it is a preferable method to add an alkali metal salt of carboxylic acid or sulfonic acid, or to add alkali hydroxide. 50 mol% as copolymerization (indicating alkyl, nitro, phenyl, alkoxy groups),
The copolymerization component is preferably 40 mol% or less, as long as it does not significantly affect the crystallinity of the trifunctional phenyl sulfide bond. In particular, when trifunctional or higher functional phenyl, biphenyl, naphthyl sulfide bonds, etc. are selected for copolymerization, the amount is preferably 3 mol% or less, more preferably 5 mol% or less.

Such PPS resins can be produced by common manufacturing methods, such as (1) reaction of a halogen-substituted aromatic compound with an alkali sulfide (see U.S. Pat. No. 2,513,188, Japanese Patent Publication No. 4427671 and Japanese Patent Publication No. 45-3368) (2) Condensation reaction of thiophenols in the presence of an alkali catalyst or copper salt (US Patent No. 3,274,165, British Patent No. 116)
(Refer to No. 0660) (3) Condensation reaction of aromatic compounds with sulfur chloride in the coexistence of a Lewis acid catalyst
No. 255, Belgian Patent No. 29437), etc., and can be arbitrarily selected depending on the purpose.

Fibrous reinforcements, preferably glass fibers and carbon fibers, and/or other inorganic fillers can be added to the compositions of the invention.

Glass fibers that can be used include wire diameters of 5 to 20μ.
It is preferable that the surface of non-alkali glass fibers of 1.5 m is treated with a silane blistering agent and an organic substance called a binder for focusing, and canted to a length of 3 to 6+++ m. Further, as the carbon fiber, either polyacrylonitrile type or pitch type can be used, and it is preferable that the carbon fiber has a wire diameter of 5 to 20 μm and is surface-treated with epoxy resin, nylon resin, etc., or untreated.

Furthermore, other inorganic fillers include calcium carbonate,
Talc, kaolin, clay, mineral fiber, wolstonite, calcium sulfate, silica, glass beads, short glass fiber, milled carbon fiber, titanium oxide, graphite, processed mineral fiber, etc. can be used.

The appropriate quantitative proportion of these fibrous reinforcing materials and other inorganic fillers is 20 to 70% by weight based on the total resin composition. still,
The fibrous reinforcement and other inorganic fillers can be used individually or in combination.

Furthermore, the material of the present invention may include other thermoplastic resins such as polyphenylene ether, polyacetal, polyarylate, Teflon resin, polyamide, polycarbonate, polysulfone, polyaryl sulfone, polysulfone, etc., to the extent that the object of the present invention is not impaired. One or more of ether sulfone, polyarylate, polyacetal, polyetheretherketone, polybutylene terephthalate, polyethylene terephthalate, polyamide, polyetherimide, polyethylene, epoxy resin, etc. can be added.

Polypropylene can be added to PPS by a known method. For example, powdered or pelleted PPS resin and powdered, flaked, hard granulated, or pelleted volibropylene (if necessary, reinforcing material such as glass fiber and/or other inorganic filler such as calcium carbonate) are used. (mixed together) in advance by mechanically uniformly mixing in a mixer such as a drum tumbler, and then heating, melting, and kneading processes in a screw-type single-screw or twin-screw kneading extruder, followed by cooling and turning into belent. It is done.

In addition, the precepts of the present invention may include small amounts of coloring agents, heat stabilizers, ultraviolet stabilizers, rust preventives, etc. without departing from the purpose of the present invention.
Modifiers such as crystal nucleating agents and organic silane compounds can be added.

"Example" Next, the present invention will be further explained by giving examples.

(Example-1) Powdered PP commercially available from Phillips Oil Co., Ltd. in the United States
S resin: trade name Ryton P-4 59.7% by weight, non-oxidized granular polypropylene wax Hoechstsax commercially available from Ioechst, West Germany
TM"PP230" (viscosity at 180°C according to DIN 53018: approximately 1000 mPa.S) 0. 3% by weight and chopped glass fiber manufactured by Asahi Fiher Glass; Product name: Glass Ronchi Gopped Strand CS-0
3-MA49740% by weight, total 10kg, capacity 50
The mixture was placed in a No. 1 drum-type tumbler and mixed uniformly for about 1 minute at a speed of BO rpm.

The above mixture was kneaded in an l-shaft extruder with a diameter of 65 mm and a L/D=30 vent under the conditions of a cylinder temperature of 320°C and a screw rotation speed of 10 Orpm, and then discharged from a die with a hole diameter of φ4, and after air cooling, it was made into strands. He created a beret with a length of 3 in the cutter.

Injection molding machine 15-50 manufactured by Toshiba Machine ■ with mold clamping force of 50 tons
AM type, outer diameter φ30mm, inner diameter φ28, length 10mm, draft angle 0. A mold with a 5° cylindrical cavity was installed, the mold temperature was 150°C, and the molding machine cylinder temperature was 33°C.
The injection was performed under the conditions of 0°C, injection pressure of 800 kgf/cm2, injection time of 4 seconds, and cooling time of 15 seconds. During the mold opening and ejection process after the cooling process, a pressure sensor (Switzerland K
When the mold release force acting on the ejecting pin was measured using an ISTLER 922L pressure sensor, it was 3.5 kgf, indicating that it was possible to take out the molded product from the mold cavity with an extremely small mold release force. Ta.

(Example-2) In Example I, the mold temperature during molding was 110°C, 9
The mold release force was measured at each temperature changed from 0°C to 160°C.
．． Indicates Okgf, 10kgf, 7.0kgf,
It was confirmed that the effect was excellent.

(Example 3) In Example 1, when the amount of polypropylene added was changed to 2% by weight, excellent mold release effects were exhibited in all cases. The results are shown in Table 1.

(Comparative Example-1) In Examples 1 and 2, low molecular star polyethylene resin powder (West German [Ioechs
Hoechst wax PE520), Monchnic acid wax which is a known mold release agent, silicone oil (
As shown in Table 1, when the mold temperature is high, there is a mold release effect, but when the mold temperature is medium or low temperature, the molded product cannot be released from the mold. Or,
An extremely large mold release force was required.

(Comparative Example-2) In Length Example 1, 180 according to DIN-53018
'C melt viscosity is 20, OOOmPa, SOHoe
chst company, ttoechs twax TM PP
When 690 was used, the dispersion was poor and the expected mold release effect could not be obtained.

Claims (3)

[Claims] (1) As a mold release agent for polyphenylene sulfide resin, 50%
00mPa. A polyphenylene sulfide resin composition containing polypropylene having a melt viscosity of S or less. (2) The resin composition according to claim 1, wherein 0.1 to 6 parts by weight of polypropylene wax is added to 100 parts by weight of polyphenylene sulfide resin. (3) A reinforced polyphenylene sulfide resin composition obtained by adding a fibrous reinforcing agent and/or another inorganic filler to the polyphenylene sulfide resin composition according to claim 1.