JPH08229940A - Manufacture of polycarbonate resin composition - Google Patents

Abstract

PURPOSE: To provide a method for manufacture of a resin composition wherein when a compound having a -OH group in a molecule (heat stabilizer, and weathrability modifier), and a mold releasing agent are mixed with polycarbonate resin, their additional efficiency is improved without lowering the molecular weight of the resin. CONSTITUTION: When a compound having a -OH group in a molecule (heat stabilizer, and weatherability modifier), and a mold releasing agent are mixed with polycarbonate resin, a mixture of resin and an additive is melted to be kneaded with a vented extruder, and pressure of atmosphere in a space part of a vent part is 500Torr or over.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polycarbonate resin composition. More specifically, it relates to a method for producing a polycarbonate resin composition which improves the addition efficiency of a compound having a —OH group in the molecule (heat stabilizer, weather resistance improver) and a release agent and does not reduce the molecular weight of the resin.

[0002]

2. Description of the Related Art Polycarbonate resins are originally excellent in transparency, moldability, mechanical properties, heat resistance, abrasion resistance, dimensional stability, electrical insulation properties, etc. It is widely used as a molding material for electrical equipment parts and various other industrial materials. These parts are required to have excellent mechanical properties, heat resistance (including heat discoloration resistance), and appearance, and are often used outdoors as well as indoor fluorescent lamps. Since it is often used under a light ray, it is required to have excellent weather resistance. Currently, the quality of polycarbonate resin molded products is judged by the degree of improvement in heat resistance and weather resistance.

As a method for improving the heat resistance (including heat discoloration resistance) and weather resistance of a polycarbonate resin, conventionally, various stabilizers such as antioxidants and ultraviolet absorbers have been added to the base resin. Has been adopted. Also, when manufacturing molded products by injection molding or extrusion molding, it improves the fluidity of the molten resin and makes it easier to release from molds and rolls during molding, so that molds and rolls do not become dirty or In order to eliminate poor appearance of products, certain compounds are compounded as a release agent.

When adding a resin additive such as an antioxidant, an ultraviolet absorber or a release agent to a polycarbonate resin, usually, a predetermined amount of each of the raw material resin and the resin additive is weighed and mixed with a blender or the like. Then, a method of melt-kneading the obtained mixture with a kneader such as an extruder is adopted. When melt kneading, a vent type extruder is used when melt kneading with an extruder in order to remove raw resin, residual water content of resin additives, and volatile matter generated in the process of melt kneading. To be done.

[0005]

However, according to the experiments of the present inventors, when resin additives are used in combination, a compound having a specific combination, that is, a compound having an --OH group in the molecule (heat In the case of a combination of a stabilizer, a weather resistance improver), a polyhydric aliphatic alcohol, and a release agent which is a partial ester compound of a fatty acid having 10 to 22 carbon atoms, the decrease in the molecular weight of the polycarbonate resin is remarkable, In addition, it was found that it does not exhibit weather resistance and heat stability. The cause is
Although it is currently unknown, the -OH group of the compound having an -OH group in the molecule is modified to accelerate the thermal decomposition of the polycarbonate resin and change to a compound that does not exhibit weather resistance, thermal stability, etc. It is estimated that there is.

An object of the present invention is to improve the efficiency of addition of a compound having a —OH group in the molecule (heat stabilizer, weather resistance improver) and a release agent to a polycarbonate resin, Moreover, it is to provide a method for producing a polycarbonate resin composition that does not reduce the molecular weight of the resin.

[0007]

In order to solve the above-mentioned problems, the invention of claim 1 relates to a polycarbonate resin composition which comprises melt-kneading a polycarbonate resin, a compound having an --OH group in the molecule and a release agent. In the production of the above, the above raw material resin and the additive are melt-kneaded using a vent type extruder, and the pressure of the space portion atmosphere of the vent part is set to 500.
A method for producing a polycarbonate resin composition having a torque of Torr or more is characterized.

The present invention will be described in detail below. In the present invention, the polycarbonate resin is not limited to its production method. For example, (1) a phosgene method of reacting various dihydroxydiaryl compounds with phosgene,
(2) Polymers or copolymers produced by a transesterification method in which a dihydroxydiaryl compound diphenylcarbonate is reacted, or the like. A typical example of the dihydroxydiaryl compound is bisphenol A. The polycarbonate resin may be a mixture of different raw materials or different molecular weights.

The molecular weight of the polycarbonate resin is not particularly limited as long as it can be used for manufacturing various molded products.
Usually, the resulting solution is dissolved in methylene chloride, the relative viscosity at 20 ° C. is measured with a Ubbelohde viscometer, and the calculated molecular weight is 10,000 or more. Considering
It is preferable to select in the range of 20,000 to 50,000.

In the present invention, the compound having an --OH group in the molecule refers to a heat stabilizer having at least one --OH group in the molecule, a weather resistance improver and the like. What is a heat stabilizer?
It refers to a compound represented by the following general formula (I), which acts to prevent the polycarbonate resin from being colored yellow or brown by heating during the production of a molded article.

[0011]

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Specific examples of the compound represented by the general formula (I) include pentaerythrityl tetrakis [3- (4'-hydroxy-3 ', 5'-ditertiarybutylphenyl) propionate and pentaerythrityl tetrakis ( 3,5-ditertiary butylphenyl) propionate and the like.

The weather resistance improver means that when the molded article is used outdoors or when it is used indoors under the light of a fluorescent lamp, it absorbs ultraviolet rays and deteriorates due to this. UV absorbers that act to prevent Benzophenone compounds, benzotriazole compounds, and the like are suitable as the ultraviolet absorber.

Specific examples of the benzophenone compound include 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-n-octoxy-benzophenone and 4-dodecyloxy-2-hydroxy. -Benzophenone, 2-hydroxy-4-octadecyloxy-benzophenone, 2,
2'-dihydroxy-4-methoxy-benzophenone,
2,2'-dihydroxy-4,4'-dimethoxy-benzophenone, 2,2 ', 4,4'-tetrahydroxy-
Benzophenone, 2-hydroxy-4-methoxy-5
Sulfo-benzophenone, 2-hydroxy-4-methoxy-2'-carboxy-benzophenone, 2-hydroxy-4-chloro-benzophenone and the like can be mentioned.

Specific examples of the benzotriazole compound include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and 2- (2'-hydroxy-5).
′ -Ditertiarybutylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-ditertiarybutylphenyl) benzotriazole, 2- (2 ′
-Hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-ditertiarybutylphenyl)-
5-chlorobenzotriazole, 2- (2'-hydroxy-5'-octylphenyl) benzotriazole, 2
-(2'-hydroxy-3 ', 5'-ditertiary amylphenyl) benzotriazole, 2- {2'-hydroxy-3'-(3 '', 4 '', 5 '', 6 ''-tetrahydro Phthalimidomethyl) -5'-methylphenyl} benzotriazole, 2,2-methylenebis [4-
(1,1,3,3-tetramethylbutyl) -6- (2H
-Benzotriazol-2-yl) phenol and the like.

The amount of the heat stabilizer and the weather resistance improver, which are compounds having an —OH group in the molecule, with respect to the polycarbonate resin is 0.01 to 2 parts by weight per 100 parts by weight of the resin. If it is less than 0.01 parts by weight, the thermal stability and weather resistance will not be improved, and if it is more than 2 parts by weight, it may cause defective molding, coloring, bleed-out, etc., both of which are not preferable. Among the above ranges, particularly preferred is 0.05 to 0.5 parts by weight.

In the present invention, the mold release agent means to improve the fluidity of the resin at the time of melting, to facilitate the mold release from the mold or roll at the time of molding, and to prevent the mold or roll from being soiled and the appearance of the molded product from being defective. A compound that exerts the function of Examples of the release agent include aliphatic alcohols, higher fatty acids, metal soaps and waxes. Among them, polyhydric aliphatic alcohol,
Partial ester compounds with fatty acids having 10 to 22 carbon atoms are preferred.

Examples of the polyhydric aliphatic alcohol include trihydric and hexavalent aliphatic alcohols such as glycerin, trimethylolpropane, pentaerythritol, mesoerythritol, pentitolose, hexitol and sorbitol. Examples of the fatty acid having 10 to 22 carbon atoms include undecyl acid, lauric acid, dodecyl acid, myristic acid, pentadecylic acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arachidic acid and behenic acid. The carbon skeleton of these fatty acids may have a substituent such as a hydroxyl group.

The ester compound of the above polyhydric aliphatic alcohol and the above fatty acid is preferably a substantially partial ester compound. Among them, those in which 30% or more of all the hydroxyl groups in the polyhydric alcohol are left unesterified are preferred. Specific examples include glycerin monostearate, glycerin distearate, glycerin monobehenate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol monobehenate and pentaerythritol dibehenate. Such a partial ester compound is
It may be a single kind or a mixture of two or more kinds.

The compounding amount of the above-mentioned releasing agent with respect to the polycarbonate resin is 0.005 to 100 parts by weight of the resin.
1 part by weight. If the compounding amount is less than 0.005, the releasability at the time of molding and the appearance of the molded product are not improved, and if it exceeds 1 part by weight, the gas generation amount at the time of molding becomes large. Is also not preferable. Of the above ranges, 0.01 to 0.5 parts by weight is particularly preferable.

In addition to the above-mentioned two components, the polycarbonate resin may be used in combination with another thermoplastic resin which is compatible with the molded product, or in combination with another thermoplastic resin which is incompatible with the compatibilizer, depending on the use of the molded article. Resin additives other than the above may be used alone or in combination of two or more. As resin additives other than the above, plasticizers, lubricants, dyes, pigments, antistatic agents, flame retardants, glass fibers, carbon fibers, fibrous reinforcing materials such as potassium titanate whiskers, calcium carbonate, silica, alumina, gypsum. , And fillers such as clay minerals.

To blend the above-mentioned two components, another thermoplastic resin, and a resin additive other than the above into the polycarbonate resin, the polycarbonate resin, the above-mentioned two components, and the other blended components are weighed in predetermined amounts, and a tumbler and a blender are blended. , A Henschel mixer or the like, and the obtained mixture may be kneaded with an extruder.

The extruder may be either a single-screw extruder or a twin-screw extruder as long as it is a vent type extruder. In the case of a single-screw extruder, the one of the dullage type screw is preferable, and in the case of a twin-screw extruder,
It may be biaxial in the same direction or biaxial in different directions. Among the extruders, the different-direction twin-screw extruder is particularly preferable.

According to the method of the present invention, the polycarbonate resin and the additive (a compound having a --OH group in the molecule and a release agent) are melt-kneaded by using a vent type extruder, and The pressure of the atmosphere in the space is 500 Tor
r or more. According to the experiments conducted by the inventors of the present invention, when the pressure of the atmosphere in the vent space of the extruder is less than 500 Torr, the reason is unclear, but the molecular weight of the polycarbonate resin is drastically reduced, and the popper and vent parts are also reduced. Air (oxygen) enters the inside of the cylinder from the above and comes into contact with the molten polycarbonate resin, which causes yellow coloring of the resin, which is not preferable. The pressure of the atmosphere of the vent space is preferably 700 Torr or more,
Particularly preferably, the pressure is 760 Torr (1 atm) or more.

To adjust the pressure of the vent space of the extruder to 1 atm or less, a vacuum pump may be connected to the vent space to reduce the pressure. In the case of adjusting to 2, the method may be performed by injecting an inert gas such as nitrogen gas into the vent portion and sealing it. Alternatively, a method of depressurizing with a vacuum pump while injecting and sealing an inert gas into the space of the vent portion may be used. When pressurizing the space of the vent with an inert gas, the upper limit of the pressure is 50 atm or less, particularly preferably 1
It is 0 atm or less.

The polycarbonate resin composition obtained by the method of the present invention is widely used as a molding material for building material parts, automobile parts, electric equipment parts and various industrial materials used outdoors. Also, it is suitable as a molding material for daily sundries, household appliances, office supplies, office equipment parts, etc., which are used indoors under the light of a fluorescent lamp.

[0027]

INDUSTRIAL APPLICABILITY The present invention has special advantageous effects as follows, and its industrial utility value is extremely large. 1. According to the method of the present invention, a vent type extruder is used for melt kneading, and the pressure in the vent space is set to 500.
Since it is not less than Torr, the molecular weight of the polycarbonate resin does not decrease, and the -OH group of the compound having an -OH group is not modified, and the compound has an -OH group in the molecule. The heat stabilizer and the weather resistance improver sufficiently exhibit their original functions. 2. The polycarbonate resin composition obtained by the method of the present invention is colored in the molding step because a heat stabilizer, which is a compound having an —OH group in the molecule, a weather resistance improver, etc., is contained in the resin without losing its activity. Molded products with less
Even if the molded product is exposed to the outdoors, it has excellent weather resistance and there is little discoloration or deterioration of physical properties.

[0028]

EXAMPLES The present invention will be described below in detail based on Examples and Comparative Examples.
The present invention is not limited to the following description example. In the examples described below, measurement of the molecular weight of polycarbonate,
Analysis of the ultraviolet absorber in the polycarbonate resin composition,
The weather resistance test of the polycarbonate resin composition, the color tone (YI value) of the molded product, etc. are measured by the methods described below.

(1) Measurement of Polycarbonate Molecular Weight A predetermined amount of a polycarbonate resin composition was weighed and dissolved in methylene chloride, and the resulting solution was measured for relative viscosity at 20 ° C. with an Ubbelohde viscometer. According to the method of calculating the molecular weight by calculation from the measured value.

(2) Analysis of UV Absorber Polycarbonate resin composition was treated with deuterated chloroform (purity 9
Dissolved in tetrabromethane (purity 9
(9.0% or more) by adding an internal standard, and by a nuclear magnetic resonance apparatus (JEOL Ltd., #JEOL, α-400 type), 1
According to the method of measuring 1 H-NMR spectrum.

(3) Weather resistance test A test piece for measuring Izod was molded from the polycarbonate resin composition by an injection molding machine (# J75EII, manufactured by Japan Steel Works, Ltd.). This test piece was subjected to an accelerated weather resistance test using a weather o-meter (Suga Test Instruments Co., Ltd., black panel, 63 ° C, rainfall 12 minutes / 60 minutes), and irradiation for a predetermined time (3000 hours irradiation, 5000 hours irradiation) The Izod impact strength of the subsequent test piece and the color tone (YI value) of the molded product were measured. (4) Izod impact strength Measured according to ASTM D-256.

(5) Measurement of color tone (YI value) of molded product From a polycarbonate resin composition, an injection molding machine (manufactured by Japan Steel Works, # J75EII or manufactured by Meiki Seisakusho, #M) is used.
-60 / 100-ST), 60mm × 60mm × 3
Using a mold with a cavity of mm (thickness),
Cylinder temperature 300 ℃, mold temperature 80 ℃, injection pressure 6
A flat plate was formed under the condition of 00 kg / cm ² . About the obtained flat plate, a digital colorimetric color difference meter (manufactured by Suga Test Instruments Co., Ltd., # SM-
(5-CH type), XYZ tristimulus values were measured, and a YI (Yellowness Index) value was calculated by the following formula.
That is, YI = {(1.28X-1.06Z) / Y}
X100.

[Example 1] Polycarbonate (manufactured by Mitsubishi Chemical Co., ^TM Novarex # 7022PJ, molecular weight: 300)
00) 100 parts by weight of glycerin fatty acid ester (Riken Vitamin Co., Riquemal # S-100A) 0.05
Parts by weight, hindered phenol compound (heat stabilizer: manufactured by Nippon Ciba Geigy, ^TM Irganox # 1010).
10 parts by weight, benzotriazole-based compound (UV absorber: manufactured by American Cyanamid, Siasorb #U
V5411) 0.20 parts by weight were weighed and uniformly mixed with a Henschel mixer to obtain a mixture.

The mixture thus obtained was vent-type single-screw extruder (# HME-11, manufactured by Mitsubishi Heavy Industries, Ltd.) in which the vent opening was covered and a nitrogen supply pipe was connected to the base of the cylindrical vent.
5. The vent is arranged between the resin supply zone and the metering zone. ), The space of the vent was sealed with nitrogen gas, the pressure was 760 Torr (Example 1), the resin temperature was 320 ° C., and the extrusion rate was 500 kg /
Melt kneading was continuously carried out at a rate of hr to obtain pellets. The obtained pellets were subjected to molecular weight measurement, analysis of ultraviolet absorber, weather resistance test, analysis of color tone (YI value) of molded article, and evaluation test. The results are shown in Table-1.

Comparative Example 1 Pellets were obtained by the same procedure as in Example 1, except that the pressure in the vent space was changed to 20 Torr in the example described in Example 1. The obtained pellets were subjected to molecular weight measurement, analysis of ultraviolet absorber, weather resistance test, analysis of color tone (YI value) of molded article, and evaluation test. The results are shown in Table-1.

[0036]

[Table 1]

From Table-1, the following is clear. (1) In the production of the resin composition according to the present invention, the pressure in the vent space of the vent type extruder was extruded at a pressure higher than 500 Torr.
Moreover, the residual amount of the benzotriazole-based compound is large, the color tone (YI value) of the molded product after the weather resistance test is small, and the weather resistance is excellent.

(2) On the other hand, in Comparative Example 1 in which the pressure in the vent space of the vent type extruder was set as low as 20 Torr and extruded, the decrease range of the molecular weight was large and the residual amount of the benzotriazole compound was large. There are few, the color tone (YI value) of the molded product after the weather resistance test is large, and the weather resistance is poor.

[Examples 2 to 4, Comparative Examples 2 to 6] 100 parts by weight of polycarbonate (same as above), 0.10 parts by weight of hindered phenol compound (same as above), glycerin fatty acid ester (same as above) and benzotriazole compound. (Same as above) was variously changed to the amounts shown in Table 2, weighed respectively, and uniformly mixed with a Henschel mixer to obtain a mixture.

A vent type uniaxial extruder (manufactured by Isuzu Kako Co., Ltd., 30φ, the vent was a resin feed zone) was provided with a lid at the opening of the vent and a nitrogen feed pipe connected to the base of the tubular vent. And the metalling zone)), the space of the vent is sealed with nitrogen gas or not sealed, and the pressure of the vent space is also changed as shown in Table-2. Then, the resin temperature was 330 ° C., the extrusion rate was 7 kg / hr, and the mixture was continuously melt-kneaded to obtain pellets. The obtained pellets were analyzed for molecular weight, analyzed for ultraviolet absorbent, weather resistance test, etc., and evaluated. The results are shown in Table-2.

[0041]

[Table 2]

From Table 2, the following is clear. (1) According to the method of the present invention, a vent type extruder is used for melt kneading, and the atmosphere in the vent section is set to 500 Tor.
When it is r or more, the decrease in the molecular weight of the polycarbonate resin is small, and the decrease amount of the compound having an —OH group (heat stabilizer, weather resistance improver) is small (the remaining amount is large). Little coloring (see Examples 2 to 4).

(2) When the vent of the vent type extruder is sealed with nitrogen gas, the coloring during molding is further reduced (see Examples 2 to 4). (3) On the other hand, when the atmosphere in the vent portion is melt-kneaded without using the method of the present invention at 500 Torr or less, the decrease in the molecular weight of the polycarbonate resin is large, and a compound having an -OH group (heat The amount of reduction of the stabilizer and the weather resistance improver is large (the remaining amount is small), and therefore the coloring during molding is remarkable (see Comparative Examples 2 to 6).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 69/00 KKJ C08L 69/00 KKJ B29K 69:00 (72) Inventor Kenichi Haga Kitakyushu City, Fukuoka Prefecture 1-1 Kurosaki Shiroishi, Hachiman Nishi-ku, Kurosaki Development Laboratory, Mitsubishi Chemical Co., Ltd. (72) Inventor Kazumasa Morita 1-1, Kurosaki Shiroishi, Yawatanishi-ku, Kitakyushu, Fukuoka Mitsubishi Chemical Corporation, Kurosaki Development Laboratory

Claims (3)

[Claims] 1. Polycarbonate resin, --OH in the molecule
In producing a polycarbonate resin composition by melt-kneading a compound having a group, and a release agent, the raw material resin and additives are melt-kneaded using a vent-type extruder, and the space of the vent part Atmospheric pressure of 500 Torr
A method for producing a polycarbonate resin composition characterized by the above. 2. The production method according to claim 1, wherein the release agent is a partial ester compound of a polyhydric aliphatic alcohol and a fatty acid having 10 to 22 carbon atoms. 3. The manufacturing method according to claim 1, wherein the atmosphere for melting and kneading the raw material resin and the additive is sealed with an inert gas.