JP2002161202A - Flame retardant polycarbonate resin - Google Patents

Abstract

(57) [Summary] [Object] To provide a flame-retardant polycarbonate resin which is excellent in environmental suitability without using a halogen-based flame retardant, and is also excellent in moldability, heat stability and impact resistance. [Constitution] A mixture of a polycarbonate resin (A) in which a structural unit of the following general formula (I) accounts for 50 mol% or more and a polycarbonate resin (B) in which a structural unit of the following formula (II) accounts for 50 mol% or more: A flame-retardant polycarbonate resin composition containing 5 to 25 mol% of a structural unit represented by the following general formula (I). Embedded image [In the formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 3 carbon atoms. [Chemical formula 2]

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant polycarbonate resin which is excellent in environmental suitability without using a halogen-based flame retardant, and is excellent in moldability, heat stability and impact resistance.

[0002]

2. Description of the Related Art Conventionally, polycarbonate resins are excellent in transparency, mechanical properties, heat resistance, dimensional stability, etc., and therefore are used as engineering plastics for electric / electronic parts, office equipment parts, automobile parts and the like. Widely used in the field.

[0003] In these fields, in many cases, flame retardancy is required, and conventionally, halogen-based flame retardants,
Alternatively, a method of adding an antimony-based flame retardant has been adopted, but the halogen-based flame retardant corrodes surrounding metal members, and there is a concern that the effect on the environment at the time of disposal may be caused. As a halogen-based flame retardant, for example, replacement with an organic phosphorus-based flame retardant such as triphenyl phosphate has been studied. However, these phosphorus-based flame retardants have the drawback of impairing the heat resistance, wet heat resistance, hydrolysis resistance, impact resistance, etc. of the resin. A method of copolymerizing (3,5-dimethyl-4-hydroxyphenyl) methane [tetramethylbisphenol F] has been proposed (see, for example, JP-A-60-186528). However, there are drawbacks in that the flowability of the resin is reduced, the molding processability is poor, the thermal stability such as coloring during molding is poor, and the impact resistance is further lowered.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art. Therefore, the present invention is excellent in environmental suitability without using a halogen-based flame retardant, and has good moldability and heat stability. It is an object of the present invention to provide a flame-retardant polycarbonate resin having excellent heat resistance and impact resistance.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object. That is, the present invention provides a polycarbonate resin having a structural unit represented by the following general formula (I) occupying 50 mol% or more. (A) and the structural unit of the following formula (II) is 50
A flame-retardant polycarbonate resin which is a mixture with a polycarbonate resin (B) occupying at least mol% and contains 5 to 25 mol% of a structural unit represented by the following general formula (I).

[0006]

Embedded image

[In the formula (I), R ¹ , R ² , R ³ and R ⁴
Each independently represents an alkyl group having 1 to 3 carbon atoms. ]

[0008]

Embedded image

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One polycarbonate resin (A) constituting the flame-retardant polycarbonate resin of the present invention is:
The structural unit of the general formula (I) accounts for 50 mol% or more, and it is difficult to achieve the object of the present invention with other polycarbonate resins.

Here, in the structural unit of the general formula (I), specific examples of the alkyl group of R ^{1 to} R ⁴ include a methyl group, an ethyl group and a propyl group.
Among them, R ¹ , R ² , R ³ and R ⁴ are preferably all methyl groups.

The structural unit of the general formula (I) in the polycarbonate resin (A) is represented by bis (3,5-dimethyl-4-hydroxyphenyl) methane [tetramethylbisphenol F] as a diol component described later. And the structural units other than the general formula (I) are derived from other diol components described later.

The terminal groups in the polycarbonate resin (A) can further improve the flame retardancy as a flame-retardant polycarbonate resin, so that at least 50% of all terminal groups are represented by the following general formula (III). It is preferable that at least 80% of all terminal groups have the terminal structure, and it is particularly preferable that at least 90% of all terminal groups have the terminal structure.

[0013]

Embedded image

[In the formula (III), R ⁵ and R ⁶ are each independently an alkyl group having 1 to 3 carbon atoms, a phenyl group,
Or a hydrogen atom. ]

Here, in the terminal structure of the general formula (III), specific examples of the alkyl group of R ⁵ and R ⁶ include a methyl group, an ethyl group and a propyl group. Specific examples of these terminal structures include, for example, p-i-propylphenyl, p-benzylphenyl, etc., of which p-i-propylphenyl is preferable.

The polycarbonate resin (A) is
The viscosity average molecular weight is preferably from 5,000 to 50,000, more preferably from 8,000 to 40,000, and particularly preferably from 10,000 to 30,000. When the viscosity average molecular weight is less than the above range, it tends to be difficult to obtain sufficient flame retardancy as a flame retardant polyester resin, while when the viscosity average molecular weight exceeds the above range, the moldability tends to be poor.

The other polycarbonate resin (B) constituting the flame-retardant polycarbonate resin of the present invention has the above formula (I)
The constituent unit of (I) accounts for 50 mol% or more, and it is difficult to achieve the object of the present invention with other polycarbonate resins.

The structural unit of the formula (II) is derived from 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] as a diol component described later. The structural units other than ()) are derived from other diol components described below.

Also, the terminal groups in the polycarbonate resin (B) can further improve the flame retardancy as a flame-retardant polycarbonate resin, so that 50% or more of all the terminal groups are represented by the general formula (III). It is preferable that at least 80% of all terminal groups have the terminal structure, and it is particularly preferable that at least 90% of all terminal groups have the terminal structure.

The flame-retardant polycarbonate resin of the present invention is a mixture of the above-mentioned polycarbonate resin (A) and the above-mentioned polycarbonate resin (B).
It is essential that the structural unit of (I) be contained in an amount of 5 to 25 mol%, and the structural unit of the general formula (I) is preferably contained in an amount of 10 to 25 mol%, particularly preferably 10 to 20 mol%. preferable. When the content of the structural unit represented by the general formula (I) is less than the above range, it is difficult to obtain sufficient flame retardancy as a flame-retardant polycarbonate resin, whereas, when the content is more than the above range, moldability, heat stability, and The impact resistance is inferior.

The polycarbonate resin (A) and the polycarbonate resin (B) in the flame-retardant polycarbonate resin of the present invention are basically prepared by a method of interfacial polymerization of a diol component and phosgene (phosgene method or interfacial weight). It is produced by a conventional production method of a polycarbonate resin such as a method (ester exchange method or melt polymerization method) by transesterification of a diol component and a carbonate such as diphenyl carbonate.

Here, the polycarbonate resin (A)
As the diol component in the above, a diol which forms the structural unit of the general formula (I), specifically, for example, bis (3,5-dimethyl-4-hydroxyphenyl) methane [tetramethylbisphenol F] or the like (3,5-
Dialkyl-4-hydroxyphenyl) methane [tetraalkylbisphenol F] is essential, and as other copolymerization components, for example, bis (4-hydroxyphenyl) methane [bisphenol F], 1,1-bis (4 '-Hydroxyphenyl) ethane, 2,2-bis (4'-hydroxyphenyl) propane [bisphenol A], 2,2-bis (3'-methyl-4'-hydroxyphenyl) propane [bisphenol C], 2, 2-
Bis (hydroxyphenyl) alkanes such as bis (3 ′, 5′-dimethyl-4′-hydroxyphenyl) propane and 2,2-bis (4′-hydroxyphenyl) butane; 1,1-bis (4′- Hydroxyphenyl) cyclopentane, 1,1-bis (4′-hydroxyphenyl)
Bis (hydroxyphenyl) cycloalkanes such as cyclohexane [bisphenol Z], bis (4-hydroxyphenyl) phenylmethane, 1,1-bis (4′-hydroxyphenyl) -1-phenylethane [bisphenol P], 1-bis (4'-hydroxyphenyl)
Bis (hydroxyphenyl) such as -1-phenylpropane and bis (4-hydroxyphenyl) diphenylmethane
Phenylalkanes, bis (4-hydroxyphenyl)
Bis (hydroxyphenyl) ethers such as ethers,
Bis (hydroxyphenyl) ketones such as bis (4-hydroxyphenyl) ketone, bis (hydroxyphenyl) sulfides such as bis (4-hydroxyphenyl) sulfide, and bis (hydroxyphenyl) such as bis (4-hydroxyphenyl) sulfoxide ) Sulfoxides, bis (hydroxyphenyl) sulfones such as bis (4-hydroxyphenyl) sulfone [bisphenol S],
Aromatic diols such as bis (hydroxyphenyl) fluorenes such as 9,9-bis (4′-hydroxyphenyl) fluorene; and a small amount of aliphatic diols, alicyclic diols, or pyroganol, phloroglucinol , 1,1,1-tri (4'-hydroxyphenyl) ethane, tetra (4-hydroxyphenyl) methane, etc.
A phenol having a valency or higher may be used.

As the diol component in the polycarbonate resin (B), 2,2-bis (4'-hydroxyphenyl) propane [bisphenol A] which forms the structural unit of the formula (II) is essential. Further, as other copolymerization components, the polycarbonate resin (A)
The same aromatic diols as those described above as the copolymerization component may be used, and a small amount of an aliphatic diol, an alicyclic diol, or a trivalent or higher phenol as described above may be used.

In the present invention, the method for producing the polycarbonate resin (A) and the polycarbonate resin (B) is preferably an interfacial polymerization method among the above-mentioned methods. In this case, in the polycarbonate resin (A), For example, bis (3,5-dimethyl-4-hydroxyphenyl) methane [tetramethylbisphenol F] and 2,2-bis (4′-hydroxyphenyl) propane [bisphenol A] in the polycarbonate resin (B) And phosgene is introduced into a mixed system of an aqueous phase of an aqueous alkali solution such as another copolymerization component used as necessary, and an organic phase of an inert organic solvent to form an oligomer having a chloroformate group at a terminal. Synthesized, followed by interfacial polycondensation in the presence of a polycondensation catalyst to produce a high molecular weight. You.

Examples of the aqueous alkali solution include aqueous solutions of alkali metal salts such as sodium hydroxide and potassium hydroxide. Among them, an aqueous sodium hydroxide solution is preferable. As the inert organic solvent, For example,
Examples thereof include halogen-based solvents such as methylene chloride, chloroform, carbon tetrachloride, and 1,2-dichloroethane, and aromatic solvents such as benzene, chlorobenzene, toluene, and xylene, among which methylene chloride is preferable.

Examples of the polycondensation catalyst include tertiary amine compounds such as triethylamine; quaternary ammonium compounds such as tetrabutylammonium chloride and benzyltributylammonium chloride; pyridine;
Examples thereof include pyridine compounds such as dimethylaminopyridine, among which dimethylaminopyridine is preferable.

The temperature during the polycondensation is -20 to 120 ° C.
The temperature is preferably 35 ° C. or lower when methylene chloride is used as the organic solvent, and further, bis (3,5-dimethyl-4-hydroxyphenyl) methane [tetramethylbisphenol F] is used. In the case of the polycondensation of the polycarbonate resin (A) using the above, the temperature is preferably 20 ° C. or lower.

In these polycondensations, terminal stoppers such as pi-propylphenol and p-
t-butylphenol, p-octylphenol, p-
Monohydric phenols such as benzylphenol and p-cumenylphenol may be used. Among them, both the polycarbonate resin (A) and the polycarbonate resin (B) in the present invention, preferably pi-propylphenol, p-benzylphenol, particularly preferably p-i
-Propylphenol is preferably used.
By using these terminal stoppers, the terminals of the polycarbonate resin (A) and the polycarbonate resin (B) can have the terminal structure represented by the general formula (III).

The flame-retardant polycarbonate resin of the present invention comprises
The polycarbonate resin (A) and the polycarbonate resin (B) are mixed, for example, by mixing respective powders or granules with a mixer such as a super mixer, a Henschel mixer, a tumbler, etc., and then a twin screw extruder, a kneader, a roll, etc. Can be prepared as a mixture by a known method such as a method of melt-kneading, or a method of mixing in a solution state,
Also, at that time, if necessary, usually used antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, lubricants, antiblocking agents, antifogging agents, plasticizers, coloring agents, dispersants,
Additives such as fillers are added, and the mixture is subjected to ordinary molding.

[0030]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 Production of polycarbonate resin (A-1) 100 parts by weight of bis (3,5-dimethyl-4-hydroxyphenyl) methane [tetramethylbisphenol F] as a diol component, 47 parts by weight of sodium hydroxide, A mixture of 686 parts by weight of water and 480 parts by weight of methylene chloride was charged into a reactor equipped with a stirrer, and 127 parts by weight of phosgene was blown into the reactor while stirring to react. After completion of the reaction, only a methylene chloride solution containing a polycarbonate oligomer was captured. The methylene chloride solution of the oligomers collected and obtained had an oligomer concentration of 2 as measured by the following method.
3.4% by weight, terminal chloroformate group concentration is 0.94
3 normal and the terminal phenolic hydroxyl group concentration is 0.821
It was a regulation.

Oligomer Concentration A methylene chloride solution of the oligomer was evaporated to dryness and measured. Terminal chloroformate group concentration The aniline hydrochloride obtained by reacting the oligomer with aniline was measured by neutralization titration with a 0.1 N aqueous sodium hydroxide solution. The color development when the oligomer having a terminal phenolic hydroxyl group concentration was dissolved in a methylene chloride, titanium tetrachloride, or acetic acid solution was measured by colorimetry at 546 nm.

Subsequently, the oligomer solution 126 m
1, pt-butylphenol 0.3 as a terminal stopper
62 g and methylene chloride (40 ml) were charged into a polymerization vessel equipped with a stirrer, and 25% by weight of sodium hydroxide was added while stirring.
20 ml of an aqueous solution, 32 ml of demineralized water and 1.7 ml of a 2% by weight aqueous solution of dimethylaminopyridine were added, and after interfacial polymerization was carried out for 3 hours, 248 ml of water and 161 ml of methylene chloride
The reaction mixture was separated by stirring for 30 minutes, and the methylene chloride solution containing the polycarbonate resin was washed with an aqueous sodium hydroxide solution, an aqueous hydrochloric acid solution and demineralized water, and finally the methylene chloride was evaporated to remove the resin. Was collected to prepare a polycarbonate resin (A-1) having a constitutional unit of the general formula (I) of 100 mol%. Regarding the obtained polycarbonate resin (A-1), the ratio of the pt-butylphenyl terminal to all the terminal groups measured by the method described below was such that the ratio of the pt-butylphenyl terminal to tetramethylbisphenol F was 2%. 0.2 mol%,
The ratio of the terminal (hydroxyl group) of tetramethylbisphenol F to tetramethylbisphenol F is 0.15 mol%.
Therefore, it was 93%, and the viscosity average molecular weight measured by the method shown below was 23,000.

In all terminal groups of pt-butylphenyl terminal
Proportion nuclear magnetic resonance apparatus (500MHz-NMR, Varian against
The peak derived from the methyl group hydrogen of tetramethylbisphenol F appearing at 2.258 ppm and the hydroxyl group at the terminal of tetramethylbisphenol F appearing at 2.21 ppm with respect to a sample solution using D-chloroform as a solvent using “Inova500” manufactured by KK Peaks derived from hydrogen and peaks appearing at 1.33 ppm derived from hydrogen of a methyl group at the terminal of pt-butylphenyl were measured, and the ratio of pt-butylphenyl terminal was calculated from the integrated value of these peaks.

The viscosity average molecular weight resin was dissolved in methylene chloride to give a concentration c of 6.00 g / l.
Was prepared, and the falling time t _{0 of} methylene chloride was 13
6. Using a 21 second Ubbelohde capillary viscometer.
The flowing time t ₁ of the resin solution was measured in a constant temperature water bath set at 0 ° C., and the viscosity average molecular weight was calculated according to the following equation. Relative viscosity η _rel = t ₁ / t ₀ Specific viscosity η _sp = η _rel -1 a = 0.438 × η _sp +1 b = 100 × η _sp / c Viscosity η = b / a Viscosity average molecular weight M _v = 3207 × η ^1.205

The polycarbonate resin (A) obtained above
-1) Dissolve 20 parts by weight and 100 parts by weight of a polycarbonate resin (B-1) ("Iupilon S3000" manufactured by Mitsubishi Gas Chemical Company) having a constitutional unit of the formula (II) of 100 mol% in methylene chloride. And evaporated to dryness to prepare a flame-retardant polycarbonate resin as a mixture of both resins.
Then, a test piece having a width of 6 mm, a length of 120 mm and a thickness of 3 mm was press-formed. No coloring was observed in the obtained test piece, and the flame retardancy measured by the method shown below was 28.1% in oxygen index OI, and the impact strength was 85 kgf · cm / cm.
Met.

Flame retardancy Oxygen index OI was measured using a candle burning tester D (manufactured by Toyo Seiki Seisaku-sho, Ltd.) in accordance with JIS K7201-2.
(%) Was measured. Impact strength Notched Izod impact strength at 23 ° C. was measured according to ASTM D256.

Example 2 A polycarbonate resin (A-2) containing 100 mol% of the structural unit of the general formula (I) was prepared in the same manner as in Example 1 except that pi-propylphenol was used as a terminal stopper. Manufactured. Regarding the obtained polycarbonate resin (A-2), the ratio of pi-propylphenyl terminal to all terminal groups measured by the method shown below was such that the ratio of pi-propylphenyl terminal to tetramethylbisphenol F was 2%. 0.0% by mole, and the ratio of tetramethylbisphenol F terminal (hydroxyl group) to tetramethylbisphenol F is 0.22% by mole.
The viscosity average molecular weight measured by the same method as described above is 2
It was 5,000.

All terminal groups at the terminal of pi-propylphenyl
In the same manner as in the measurement of the pt-butylphenyl terminal,
2. A peak derived from methyl hydrogen of tetramethylbisphenol F appearing at 2.258 ppm, a peak derived from hydroxyl hydrogen at the terminal of tetramethylbisphenol F appearing at 2.21 ppm, and p-i appearing at 1.25 ppm
Peaks derived from the methyl group hydrogen at the -propylphenyl terminal were measured, and the ratio of pi-propylphenyl terminals was calculated from the integrated values of these peaks.

Except for using this polycarbonate resin (A-2), a flame-retardant polycarbonate resin was prepared and press-molded in the same manner as in Example 1 to produce a test piece. No coloring was observed in the obtained test pieces, and the flame retardancy measured by the same method as described above was 30.3% in oxygen index OI,
The impact strength was 87 kgf · cm / cm.

Example 3 Production of polycarbonate resin (B-2) Instead of bis (3,5-dimethyl-4-hydroxyphenyl) methane [tetramethylbisphenol F] as a diol component, 2,2-bis (4 A polycarbonate oligomer was prepared in the same manner as in Example 1 except that '-hydroxyphenyl) propane [bisphenol A] was used. The methylene chloride solution of the obtained oligomer had an oligomer concentration of 22.0% by weight, a terminal chloroformate group concentration of 0.336N, and a terminal phenolic hydroxyl group concentration of 0.052N. Subsequently, a polycarbonate resin (B) containing 100 mol% of the structural unit of the formula (II) in the same manner as in Example 1 except that this oligomer solution was used and pi-propylphenol was used as a terminal stopper. -2). For the obtained polycarbonate resin (B-2), the ratio of pi-propylphenyl terminal to all terminal groups measured by the same method as described above was such that the ratio of pi-propylphenyl terminal to bisphenol A was 3. The content was 0 mol%, and the bisphenol A terminal (hydroxyl group) could not be detected by NMR. Therefore, the content was 100%, and the viscosity average molecular weight measured by the same method as described above was 22,200.

Except that 20 parts by weight of the polycarbonate resin (A-1) obtained in Example 1 and 100 parts by weight of the polycarbonate resin (B-2) were used, the flame retardancy was the same as in Example 1. A polycarbonate resin was prepared and press molded to prepare a test piece. No coloring was observed in the obtained test piece, and the flame retardancy measured by the same method as described above was 31.2% in oxygen index OI and the impact strength was 80 kgf.
Cm / cm.

Comparative Example 1 A flame-retardant polycarbonate resin was prepared in the same manner as in Example 1 except that 100 parts by weight of the polycarbonate resin (A-1) was used, and a test piece was prepared by press molding. Brown coloration was observed in the obtained test pieces, and the flame retardancy measured by the same method as described above was 31.0 in terms of oxygen index OI.
%, And the impact strength was 9.3 kgf · cm / cm.

Comparative Example 2 A test piece was prepared by press molding in the same manner as in Example 1 except that only the polycarbonate resin (B) was used.
With respect to the obtained test piece, the flame retardancy measured by the same method as described above was 22.5% in oxygen index OI, and the impact strength was 97%.
kgf · cm / cm.

[0045]

According to the present invention, excellent environmental suitability without using a halogen-based flame retardant, moldability, heat stability,
In addition, a flame-retardant polycarbonate resin having excellent impact resistance can be provided.

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Claims (4)

[Claims] 1. The structural unit of the following general formula (I) is 50 mol%
Polycarbonate resin (A) occupying the above, and the following formula (I
A flame-retardant polycarbonate, which is a mixture with a polycarbonate resin (B) in which the constitutional unit of (I) accounts for 50 mol% or more, and contains 5 to 25 mol% of the constitutional unit of the following general formula (I). resin. Embedded image [In the formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 3 carbon atoms. [Chemical formula 2] 2. The method according to claim 1, wherein R ¹ , R ² , R
The flame-retardant polycarbonate resin according to claim 1, wherein each of ³ and R ⁴ is a methyl group. 3. The flame retardant according to claim 1, wherein at least 50% of all terminal groups of the polycarbonate resin (A) and / or (B) have a terminal structure represented by the following general formula (III). Polycarbonate resin. Embedded image [In the formula (III), R ⁵ and R ⁶ are each independently
It represents an alkyl group having 1 to 3 carbon atoms, a phenyl group, or a hydrogen atom. ] 4. The flame-retardant polycarbonate resin according to claim 1, wherein the viscosity average molecular weight of the polycarbonate resin (A) is 5,000 to 50,000.