JPH101599A - Polybutylene terephthalate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polybutylene terephthalate excellent in hue and weathering resistance and a process for producing the same. SOLUTION: This polymer mainly consists of repeating butylene terephthalate units and contains a triazine compound as an ultraviolet stabilizer. It is produced by esterifying or transesterifying an acid component based on an aromatic dicarboxylic acid and its lower alkyl ester with a glycol component based on 1,4-butanediol and polycondensing the resulting ester. Before the completion of the polycondensation reaction, 0.01-2wt.%, based on the polyester to be formed, triazine compound is added to the reaction system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to polybutylene terephthalate having excellent color tone and weather resistance, and a method for producing the same.

[0002]

2. Description of the Related Art Polybutylene terephthalate (hereinafter referred to as "P
BT ”) is a resin that balances physical properties with excellent mechanical properties, electrical properties, heat resistance, etc.
It is widely used as electric and electronic parts such as coil bobbins and automobile parts such as distributor caps. In recent years, PBT has also been used for outdoor applications, such as cover of breakers, electric light parts, etc., by utilizing its weather resistance and electric characteristics. In the field used outdoors, PBT is usually used to improve weather resistance.
Are blended with an ultraviolet light stabilizer and molded (JP-A-56-30460, JP-B-64-5068, etc.).

[0003] However, there is a drawback in that, when the ultraviolet stabilizer is blended and melt-kneaded, the resin undergoes considerable thermal deterioration, and the mechanical strength of the obtained molded product is reduced. Also, PB
Since the temperature at the time of kneading and melting of T is as high as 230 to 280 ° C., the field of the ultraviolet stabilizer is easily generated, and the residence time of the resin in the molding machine needs to be 10 minutes or less. Furthermore, since an ultraviolet stabilizer is present separately from the polymer itself, the ultraviolet stabilizer bleeds out of the molded article, and the molded article is easily dusted, and the ultraviolet stabilizer is used to maintain weather resistance for a long period of time. There is also a problem that it is necessary to increase the blending amount.

Therefore, if the subsequent kneading and mixing can be omitted by adding an ultraviolet stabilizer during the polymerization of PBT, it is possible to prevent the above-mentioned thermal deterioration of the resin and to simplify the manufacturing process. Is desirable. As an example of a means corresponding to this, a PBT having a structure in which an ultraviolet stabilizer selected from a benzotriazole-based compound, a benzophenone-based compound, and a compound having a hindered amine structure is bonded through an ester bond has been proposed (Japanese Patent Application No. Hei 6 (1994) -106686). No. 258264).

[0005] However, by adding an ultraviolet stabilizer during polymerization, the ultraviolet stabilizer is exposed to high temperature and high vacuum conditions for a long time. In the case of kneading, it is exposed to a high temperature, but it is as short as several minutes. Therefore, when an ultraviolet stabilizer is actually added at the time of polymerization, there are problems such as insufficient weather resistance of the polymer obtained by volatilization, decomposition, reaction, etc. of the ultraviolet stabilizer itself, and coloring of the polymer. It could not be a superior product.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a PBT having excellent weather resistance and good color tone.

[0007]

The present inventors have conducted intensive studies to achieve the above object. As a result, PBT containing a specific compound as an ultraviolet stabilizer can be colored even if the ultraviolet stabilizer is added during polymerization. The present invention has been found to have a good color tone without performing the method. That is, the present invention
1. Polybutylene terephthalate which is a polyester having butylene terephthalate as a main repeating unit and contains a triazine compound as an ultraviolet stabilizer,
2. Subjecting an acid component mainly composed of an aromatic dicarboxylic acid or a lower alkyl ester thereof to a glycol component mainly composed of 1,4-butanediol to an esterification reaction or a transesterification reaction, and then performing a polycondensation reaction. By the way, when producing the polyester, at the time before the end of the polycondensation reaction, 0.0 to the produced polyester
The method for producing polybutylene terephthalate according to the above item 1, wherein 1 to 2% by weight of a triazine compound is added.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The polybutylene terephthalate of the present invention is a polyester having butylene terephthalate as a main repeating unit. This is a polyester containing an aromatic dicarboxylic acid or a lower alkyl ester thereof as a main acid component and 1,4-butanediol as a main glycol component. In the present invention, examples of the aromatic dicarboxylic acid or its lower alkyl ester include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and their lower alkyl esters, among which terephthalic acid or dimethyl terephthalic acid is used. Preferably, it is used in an amount of at least 75 mol%, preferably at least 80 mol%, most preferably at least 90 mol% in the acid component. These acid components may be used alone or in combination of two or more.

[0009] In addition to the above compounds, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid and oxalic acid or lower alkyl esters thereof can be used as the copolymerization component. In addition to these, a small amount of an anhydride such as a carboxylic acid having three or more functions such as trimellitic acid or an acid such as trimellitic anhydride can be used. As the lower alkyl ester of aromatic dicarboxylic acid, the main target is a methyl ester, but one of ethyl ester, propyl ester, butyl ester and the like,
Alternatively, two or more kinds may be used in combination, and may be arbitrarily selected depending on the purpose.

In the present invention, glycol components other than 1,4-butanediol include ethylene glycol,
One or a mixture of two or more of alkylene glycols such as propylene glycol, 1,6-hexanediol, neopentyl glycol, decamethylene glycol, cyclohexanemethanol, poly (oxy) ethylene glycol, polytetramethylene glycol, and polymethylene glycol And may be arbitrarily selected depending on the purpose. Further, a small amount of a polyhydric alcohol component such as glycerin may be used, or a small amount of an epoxy compound may be used.

The proportion of the 1,4-butanediol component in the glycol component is usually at least 75 mol%, preferably at least 80 mol%, and most preferably at least 90 mol%. The polybutylene terephthalate of the present invention is characterized by containing a triazine compound as an ultraviolet stabilizer. The triazine-based compound used as an ultraviolet stabilizer in the present invention is a compound represented by the following formula (I).

[0012]

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(Wherein, R ¹ , R ² , and R ³ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group which may have a substituent.) From Japan Ciba Geigy Co., Ltd.
The compound represented by the following formula (II) which is sold under the trade name of NUVIN) 1577FF is preferred.

[0014]

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The amount of the triazine compound is 0.01 to 2% by weight, preferably 0.02 to 1% by weight, based on the produced polyester. More preferably, 0.0
The content is 5 to 0.08% by weight, most preferably 0.1 to 0.5% by weight. If the amount is too small, sufficient weather resistance cannot be obtained. On the other hand, if the amount is too large, the effect of improving the weather resistance does not change, leading to deterioration in tensile elongation and increase in cost, which is not preferable.

The polybutylene terephthalate of the present invention comprises
Subjecting an acidic component mainly composed of an aromatic dicarboxylic acid or a lower alkyl ester thereof to a glycol component mainly composed of 1,4-butanediol for an esterification reaction or a transesterification reaction, and then performing a polycondensation reaction. It is manufactured by The molar ratio of glycol component / acid component in the esterification reaction or transesterification reaction is 2.0 or less,
Preferably it is 1.0 to 1.6.

Examples of the catalyst used in the esterification reaction, transesterification reaction, and polycondensation reaction include titanium compounds such as tetraalkyl titanates, germanium compounds such as germanium dioxide, antimony compounds such as antimony trioxide, and magnesium such as magnesium acetate. Examples thereof include compounds, tin compounds such as tin acetate, and among them, use of a titanium compound is preferred because the polymerization activity is improved during the polycondensation reaction.

As a specific example of the titanium compound, tetra-
Examples thereof include n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-t-butyl titanate, tetraphenyl titanate, tetracyclohexyl titanate, and tetrabenzyl titanate. Among them, tetraalkyl titanates are preferred, and tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate and tetra-t-butyl titanate are particularly preferred. Also, two or more of these titanium compounds may be used in combination.

The amount of the catalyst to be added is 50 to 300 ppm, preferably 100 ppm, as a metal based on the produced polyester.
To 200 ppm, particularly preferably 120 to 180 ppm
It is. These catalysts may be added at the start of the esterification reaction or transesterification reaction, at the time of esterification reaction or transesterification reaction, after the esterification reaction or transesterification reaction, at the time of polycondensation reaction, or the like. It is preferable to add in portions during the transesterification reaction and after the esterification or transesterification reaction and before the start of the polycondensation reaction.

The reaction temperature during the esterification or transesterification is usually from 120 to 280 ° C., preferably from 14 to 280 ° C.
0 to 240 ° C, and the reaction time is about 2 to 4 hours. The polycondensation reaction is performed under a reduced pressure of 3 torr or less, and the reaction temperature is usually 230 to 270 ° C, preferably 245 to 26 ° C.
0 ° C., and the reaction time is about 2 to 5 hours. The polycondensation reaction is preferably performed at a reaction temperature of 270 or lower because the thermal decomposition reaction is suppressed and the number of terminal carboxyl groups is reduced. In addition, various additives such as a heat stabilizer, an antioxidant, a crystal nucleating agent, a flame retardant, an antistatic agent, and a release agent may be added as long as the characteristics of the PBT are not impaired.

In the present invention, the triazine compound as an ultraviolet stabilizer can be added at any stage during the esterification reaction or transesterification reaction, the polycondensation reaction, and the melting and kneading after the polycondensation. However, the addition at any time before the end of the polycondensation reaction, that is, in the esterification or transesterification reaction or the polycondensation reaction, eliminates the need to knead various additives into the PBT after the end of the polycondensation reaction, This is preferable because the crowding step can be omitted, leading to cost reduction. In addition, considering the operability, it is more preferable to add the compound after the latter stage of the esterification reaction or the transesterification reaction, particularly immediately before the polycondensation reaction.

The method of adding the above-mentioned ultraviolet stabilizer is not particularly limited, and includes, for example, a method of adding it in a solid state such as powder and pellets, a method of heating it to a temperature above its melting point and adding it as a melt, A method of dispersing in a suitable solvent such as butanediol or the like and adding it as a slurry may be mentioned. In the conventional method, by adding an ultraviolet stabilizer during polymerization,
Since the UV stabilizer is exposed to high temperature, long time and high vacuum conditions, the weather resistance of the polymer is insufficient due to volatilization, decomposition and reaction of the UV stabilizer itself, and the polymer is colored yellow, It could not be a product. In the present invention, a PBT with little coloring and excellent weather resistance can be obtained also by a method of adding an ultraviolet stabilizer during the production of a polymer.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the description of the examples unless it exceeds the gist. In the examples, "parts" means "parts by weight". The evaluation method of this example is described below.

(Residual rate of ultraviolet stabilizer) The content of the ultraviolet stabilizer in the obtained polymer was measured by proton NMR.
(GSX-400 nuclear magnetic resonance apparatus manufactured by JEOL Ltd.), and the ratio to the added amount was calculated as the residual ratio. (Color tone measurement) Nippon Denshoku Industries Co., Ltd. measurement color difference meter (Z-
The color tone (L value, a value, b value) was measured using a 300A model.

(Weather resistance)
Injection molding at a temperature of 260 ° C. and a mold temperature of 80 ° C.
mm, 35 mm wide, 1 mm thick rectangular test piece,
Exposure this to the weather meter for 200 hours, weather resistance
Tested. Weather meter: DEW cycle sunshine weather
-Meter Test condition: 60 minute cycle Light source: Carbon arc Upper SLEM-U
 Lower SLE-L temperature: 63 ° C. ± 2 ° C. The color tone of the test piece subjected to the weather resistance test was measured by the above method.
And the color tone (L₀, A₀, B₀)
Color (L₁, A ₁,
b₁) Was calculated by the following equation.

[0026]

ΔE = ((L ₁ −L ₀ ) ² + (a ₁ −a ₀ ) ²
+ (B ₁ −b ₀ ) ² ) ^{1/2 The} UV stabilizers used in the Examples and Comparative Examples are shown below.

[0027]

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[0028]

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Example 1 194 parts of dimethyl terephthalate, 108 parts of 1,4-butanediol and 106 pp of tetrabutyl titanate
m (in terms of titanium metal / dimethyl terephthalate) was added, and a transesterification reaction was performed at 150 ° C. to 215 ° C. for 3 hours. After the transesterification, a triazine-based compound [TIN manufactured by Nippon Ciba Geigy Co., Ltd.] is used as an ultraviolet stabilizer.
UVIN577FF (formula 1)] was added in an amount of 0.2% by weight (based on the polymer). 210-2 with [η] = 0.85 as target
The polycondensation reaction was performed under reduced pressure at 45 ° C. 1 torr from normal pressure
The pressure was gradually reduced to 85 r over 85 minutes, and at the same time, kept at 245 ° C. at 0.3 to 0.7 torr. The reaction was terminated when a predetermined stirring power was reached, and the polymer was extracted.
For the obtained polymer, the residual ratio of the ultraviolet stabilizer, the color tone (L ₀ , a ₀ , b ₀ ) and the color tone (L ₁ , a ₁ , b ₁ ) after exposure treatment with a weather meter were measured.
ΔE was calculated. The results are shown in Table 1.

Example 2 The procedure of Example 1 was repeated except that a triazine compound [TINUVIN577FF (formula 1) manufactured by Nippon Ciba Geigy Co., Ltd.] was added as an ultraviolet stabilizer in an amount of 0.4% by weight (based on polymer). . The results are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated except that a benzophenone compound [SEESORB # 1001 (formula 2) manufactured by Cipro Kasei Co., Ltd.] was added as an ultraviolet stabilizer in an amount of 0.2% by weight (based on polymer). went. (The obtained polymer was considerably colored (b value was large), and therefore, the weather resistance test was not performed.) The results are shown in Table 1.

Comparative Example 2 Same as Example 1 except that a benzophenone compound [Mark LA-51 (formula 3) manufactured by Asahi Denka Co., Ltd.] was added as an ultraviolet stabilizer in an amount of 0.2% by weight (based on polymer). I went to. (The obtained polymer was considerably colored (b value was large), and therefore, the weather resistance test was not performed.) The results are shown in Table 1.

Comparative Example 3 Same as Example 1 except that a benzotriazole-based compound [Mark LA-31 (formula 4) manufactured by Asahi Denka Co., Ltd.) was added as an ultraviolet stabilizer in an amount of 0.2% by weight (based on polymer). I went to. (The obtained polymer was considerably colored (b value was large), and therefore, the weather resistance test was not performed.) The results are shown in Table 1.

Comparative Example 4 The same procedure as in Example 1 was carried out except that 0.2% by weight (based on polymer) of a benzotriazole compound [TINUVIN 234 (formula 5) manufactured by Ciba-Geigy Japan Ltd.] was added as an ultraviolet stabilizer. Was. (The obtained polymer was considerably colored (b value was large), and therefore, the weather resistance test was not performed.) The results are shown in Table 1.

Comparative Example 5 Hindered amine compound [TINUVIN 770 (formula 6) manufactured by Nippon Ciba Geigy Co., Ltd.] as an ultraviolet stabilizer
Was performed in the same manner as in Example 1 except that 0.3% by weight (based on the polymer) was added. The results are shown in Table 1.

Comparative Example 6 A benzotriazole compound [UV5411 (formula 7) manufactured by Shiraishi Calcium Co., Ltd.] was used as an ultraviolet stabilizer in an amount of 0.3.
The same procedure as in Example 1 was carried out except that the amount by weight (based on the polymer) was added. The results are shown in Table 1.

Comparative Example 7 The procedure of Example 1 was repeated except that no ultraviolet stabilizer was added. The results are shown in Table 1.

[0038]

[Table 1]

From the above results, PBT containing a triazine compound as an ultraviolet stabilizer has a small b value and good color tone, and has a small ΔE value and excellent weather resistance. When a benzotriazole-based compound or a benzophenone-based compound is used, the b value is large and considerable coloring is observed. When a hindered amine compound is used, the b value is small, but ΔE is large and the weather resistance is poor.

[0040]

According to the present invention, by adding a specific ultraviolet stabilizer at the time of polymer production, coloring is reduced,
Polyester excellent in weather resistance can be obtained at low cost.

Claims (2)

[Claims] 1. Polybutylene terephthalate which is a polyester containing butylene terephthalate as a main repeating unit and contains a triazine compound as an ultraviolet stabilizer. 2. An esterification reaction or a transesterification reaction between an acid component containing an aromatic dicarboxylic acid or a lower alkyl ester thereof as a main component and a glycol component containing 1,4-butanediol as a main component. In producing a polyester by performing a condensation reaction, a triazine-based compound is added in an amount of 0.01 to 2% by weight based on the produced polyester before the completion of the polycondensation reaction. A process for producing the described polybutylene terephthalate.