JP3374548B2 - Polybutylene terephthalate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polybutylene terephthalate in which an ultraviolet stabilizer is bound to the end of the main chain of a polymer by an ester bond. This polybutylene terephthalate has excellent weatherability and moldability, and is useful as a molding material for automobile parts, electric parts and the like.

[0002]

2. Description of the Related Art Polybutylene terephthalate is a resin that has a good balance of physical properties such as mechanical properties, electrical properties, heat resistance, etc., and is widely used in electrical parts such as connectors and coil bobbins, and automobile parts such as distributor caps. It is used. Recently, polybutylene terephthalate has also been used for outdoor use by taking advantage of its heat resistance and electric characteristics, for example, a breaker cover, an electric lamp component, and the like. In the field used outdoors, polybutylene terephthalate is usually blended with an ultraviolet stabilizer in order to improve weather resistance, and this is molded (JP-A-56-30460, JP-B-64-64). Fifty
No. 68, etc.).

However, there is a drawback in that polybutylene terephthalate undergoes considerable thermal deterioration in the blending and melt-kneading of the ultraviolet stabilizer, and the mechanical strength of the resulting molded article is lowered. Further, since the temperature at the time of kneading and melting the polybutylene terephthalate is as high as 230 to 280 ° C., the ultraviolet stabilizer is likely to be decomposed, and the residence time of the resin in the molding machine needs to be 10 minutes or less. Furthermore, since an ultraviolet stabilizer exists separately from polybutylene terephthalate, the ultraviolet stabilizer bleeds out from the molded product, and the molded product tends to be dusty, and the ultraviolet stabilizer is used to maintain weather resistance for a long time. It is necessary to increase the compounding amount of.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a polybutylene terephthalate having a functional group having an ultraviolet absorbing function at the terminal of the main chain of the polymer itself, which is excellent in weather resistance, and is also excellent in thermal stability and moldability. For the purpose of providing.

[0005]

The present invention relates to a polyester having butylene terephthalate as a main repeating unit , wherein the poly (butylene terephthalate) is added to a carboxyl group or a hydroxyl group of the polyester main chain.
Te of 0.008 to 1.6 wt%, a hydroxyl group, UV stabilizers selected from compounds having Ruhi Ndadoamin system structure having a selected functional groups than carboxyl groups and carboxylic acid ester groups are ester bonds The present invention provides a polybutylene terephthalate having a structure bound by Further, the present invention is mainly based on butylene terephthalate.
Polyester used as a return unit
The carboxyl or hydroxyl group of the
0.008-1.6 relative to butylene terephthalate
% By weight of hydroxyl, carboxyl and carbo groups
Hindered having a functional group selected from acid ester groups
UV stabilizer selected from compounds having amine structure
And hydroxyl group, carboxyl group and carboxylic acid
Benzotriazo having a functional group selected from ester groups
UV stabilizer, which is selected from
Polybutylene terephthalate with a structure bonded by bonding
It is provided.

[0006]

[Function] Since polybutylene terephthalate has a group having an ultraviolet absorbing function in the molecule, this polymer itself
Excellent weather resistance. Further, it does not decompose even at a high temperature of 240 to 300 ° C. and can be stably molded.

[0007]

SUMMARY OF THE INVENTION Polybutylene terephthalate The polybutylene terephthalate of the present invention comprises a structural unit of butylene terephthalate represented by the following formula (I).

[0008]

[Chemical 1]

A benzotriazole-based compound having at least one group selected from a hydroxyl group, a carboxyl group and a carboxylic acid ester group in the molecule at the molecular end of the polyester, which is a polyester containing benzophenone -Based compounds and ultraviolet stabilizers selected from compounds having a hindered amine structure have an intrinsic viscosity (η) of 0.6 to
Polybutylene terephthalate of 1.6. The amount of the UV stabilizer ester-bonded to the molecular end of this polymer was 0.008 with respect to polybutylene terephthalate.
~ 1.6% by weight, preferably 0.016 to 0.8% by weight
Is. More preferably, 0.04 to 0.64% by weight,
Most preferably, it is 0.08 to 0.4% by weight. If this amount is too small, sufficient weather resistance cannot be obtained. On the other hand, if the amount is too large, no further improvement in weather resistance can be expected, and conversely, the tensile elongation of the molded product decreases. Hydroxyl group (-O
In the ultraviolet stabilizer having H), a carboxyl group (—COOH) or a carboxylic acid ester group, examples of the carboxylic acid ester group include the following ester groups.

[0010]

## STR2 ## host lattice ～COOCH ₃ host lattice ~COOC ₂ H ₅ host lattice ~COOC (CH _{3) 3} host lattice _{~CH 2 CH 2 COO (CH 2} · CH 2 O)
_n H (where, n is an integer from 1 to 20.) host lattice _{~CH 2 CH 2 COO (CH 2} · CH 2 O)
_n COOCH ₂ CH ₂ to mother skeleton (where n is 1 to 20)
Is an integer. )

The benzotriazole compound as an ultraviolet stabilizer is a compound represented by the following formula (II).

[0012]

[Chemical 3]

[In the formula, R ¹ , R ² and R ^{3 each} have a hydrogen atom, a hydroxyl group, a carboxyl group or a carboxylic acid ester group, and at least one of them is a substituent other than a hydrogen atom. ] Specifically, Tinubin (TI
NUVIN) 213 sold under the trade name of the following formula (II
A benzotriazole compound represented by I) is preferred.

[0014]

[Chemical 4]

[In the formula, n is a number of 11-12. Further, the benzophenone-based compound as the ultraviolet stabilizer is a compound represented by the following formula (IV).

[0016]

[Chemical 5]

[Wherein R ⁴ , R ⁵ , and R ⁶ are hydrogen atoms,
It has a hydroxyl group, a carboxyl group or a carboxylic acid ester group, and at least one of them is a substituent other than a hydrogen atom. Furthermore, the compound having a hindered amine structure as an ultraviolet stabilizer is a compound represented by the following formula (V).

[0018]

[Chemical 6]

[In the formula, R ⁷ is a hydrogen atom or a lower alkyl group having 1 to 10 carbon atoms. In the formula, R ⁸ is a substituent having a hydroxyl group, a carboxyl group or a carboxylic acid ester group. ] Specifically, the following are mentioned.

[0020]

[Chemical 7]

These ultraviolet stabilizers may be used alone or in admixture of two or more. Therefore, the portion where these ultraviolet stabilizers are bound to the molecular ends of polybutylene terephthalate by an ester bond is as follows, for example.

[0022]

[Chemical 8]

[In the formula, A is an alkyle having 1 to 20 carbon atoms.
Group or a single bond. R⁹, R ^Ten, R¹¹And R
¹²Are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.
Group, arylalkyl group or halogen group. R
¹³Is a hydrogen atom or a lower alkyl group having 1 to 10 carbon atoms
is there. ] (Butylene terephthalate constitutional unit)
Polybutylene terephthalate is butylene terephthalate
Is the main repeating unit. This is
Leptalic acid is the main acid component, and 1,4-butanedio
It is a polyester whose main component is glycol.
The polybutylene terephthalate of the present invention may contain up to 25% by weight.
Other copolymerizable components such as polybasic acids, glycols,
It may contain a structural unit derived from xyxic acid. other
The polybasic acid component of is, for example, isophthalic acid or 2,6-naphthyl
Talendicarboxylic acid, 2,7-naphthalenedicarboxylic acid
Acid, 4,4-diphenyldicarboxylic acid, diphenoxy
Tan-4,4-dicarboxylic acid, diphenyl sulfone-
4,4-dicarboxylic acid, diphenyl ether-4,4-
Aromatic dicarboxylic acid such as dicarboxylic acid, or sebacic
Acids, aliphatic dicarboxylic acids such as adipic acid, etc.
To be Other glycol components include ethylene glycol
, Neopentyl glycol, trimethylene glycol
Le, hexamethylene glycol, decamethylene glycol
, Cyclohexanedimethanol, polyethylene glycol
And polytetramethylene glycol.
It Also, as the oxyacid component, p-hydroxybenzoate
Aromatic acid, m-hydroxybenzoic acid, 6-hydroxy-2-
For example, nafretane dicarboxylic acid.

(Production of Polybutylene Terephthalate) The polybutylene terephthalate having an ultraviolet absorbing functional group of the present invention can be used in the above-mentioned esterification reaction, transesterification reaction or polycondensation reaction of terephthalic acid with 1,4-butanediol. It is carried out by an esterification reaction or transesterification reaction and then polycondensation according to a conventional method except that an ultraviolet stabilizer is added.
As the catalyst for the esterification reaction or transesterification reaction, tin compounds and titanium compounds are preferable, and titanium compounds are most preferable. Titanium compound
There are titanium alcoholate, phenolate, etc., but usually titanium alcoholate is used, specifically, tetrabutyl titanate, tetraisopropyl titanate,
Tetramethyl titanate and the like can be mentioned. In the polycondensation reaction, the same catalysts as those used in the above-mentioned esterification reaction or transesterification reaction are used, and among them, titanium compounds are preferable. If necessary, antimony or germanium oxide or the like may be added. Here, the esterification reaction or transesterification reaction is usually performed under nitrogen at 150-
It is carried out at 280 ° C., preferably 180 to 260 ° C. for 2 to 4 hours. The amount of the catalyst used is 3 to 300 ppm, preferably 5 to 200 ppm, in terms of titanium metal, based on the amount of polymer produced in the esterification reaction or transesterification reaction.

The polycondensation reaction is performed at 240 to 300 ° C. for 2 to 5 hours under a reduced pressure of 3 Torr or less. The catalyst for the polycondensation reaction may be the one used in the previous step, but it is preferably further added. The amount of catalyst added is 0-300 pp
m, preferably 5 to 200 ppm. Polybutylene terephthalate obtained by melt polymerization may be further solid-phase polymerized. Solid phase polymerization is carried out at 150 to 210 ° C. under a flow of 3 Torr or less or an inert gas such as nitrogen gas. Considering the operability, the ultraviolet stabilizer is preferably added after the latter stage of the esterification reaction or transesterification reaction, particularly immediately before the polycondensation reaction. Examples of the method of adding the ultraviolet stabilizer include, for example, powder, a method of adding in a solid state such as pellets, a method of heating above a melting point and adding as a melt,
Examples include a method of dispersing in a suitable solvent such as 1,4-butanediol and adding as a slurry. The amount of the ultraviolet stabilizer added is 0.01 to 2% by weight, preferably 0.02 to 2% by weight, based on the obtained polybutylene terephthalate.
It is 1% by weight. More preferably, it is 0.05 to 0.8% by weight, most preferably 0.1 to 0.5% by weight. If this addition amount is too small, sufficient weather resistance cannot be obtained. On the other hand, if the amount is too large, further improvement of the weather resistance cannot be expected, and conversely, the tensile elongation of the molded product decreases.

(Polybutylene terephthalate having an ultraviolet absorbing functional group in the molecule) As described above, the polybutylene terephthalate obtained by the above-mentioned production method is mainly composed of repeating units of the butylene terephthalate represented by the formula (I). A unit (preferably 80 to 99.95% by weight) is present, and the ultraviolet stabilizer is present at the molecular end thereof in an amount of 0.008 to 1.6% by weight through an ester bond. The molecular weight of this butylene terephthalate was 30 in a 1: 1 weight mixture of phenol and tetrachloroethane.
It has an intrinsic viscosity (η) measured at 0 ° C of 0.6 to 1.6, preferably 0.8 to 1.2, and has a molecular weight similar to that of polybutylene terephthalate which is usually commercially available.

[0027]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not restricted by these examples as long as the gist thereof is not exceeded. The term "parts" in the examples means "parts by weight". Reference Example 1 194 parts of dimethyl terephthalate, 108 parts of 1,4-butanediol and 106 of tetrabutyl titanate.
ppm (in terms of titanium metal / dimethyl terephthalate) was added to the flask, and transesterification was performed at 150 to 210 ° C. for 2.5 hours . After an ester interchange reaction was completed, ultraviolet Nippon Ciba-Geigy Corp. of Tinuvin benzotriazole compound having a hydroxyl group at the molecular end of the formula (III) as a stabilizer (TINUVIN) 21
0.3 wt% of 3 was added to the flask (vs. prepolymer). Then, a polybutylene terephthalate having an intrinsic viscosity [η] of 0.85 is prepared in the range of 210 to 245.
The polycondensation reaction was carried out under reduced pressure at ℃. Reduced pressure from normal pressure to 3T
The pressure is gradually reduced to orr over 2 hours, and then 3 Torr
It is kept below. Then, the polymer was taken out of the flask, the obtained polymer was dissolved in a mixed solvent of hexafluoroisopropanol / chloroform = 2/3, methanol was added to precipitate the polymer, and the polymer was filtered, and the amount of the ultraviolet stabilizer in the methanol mother liquor was measured. Was hardly detected when analyzed (the ultraviolet stabilizer added at the end of the transesterification reaction is bound in the polymer).
GPC measurements were performed to confirm the fact that the UV stabilizer was attached to the polybutylene terephthalate molecular chain. UV absorption wavelength from the chain of PBT is about 330 nm
It is the following.

On the other hand, TINUVIN 213
In a mixed system of 400, the maximum absorption is at about 342 nm.
There is an absorption band from TINUVIN 213 down to nm. Therefore, when GPC measurement is performed at 342 nm, P bound with TINUVIN 213 is molecularly bonded.
The BT molecular chain can be selectively observed. Measurement column: G3000HXL, G4000HXL, G5000HXL (30 cm) manufactured by Tosoh Corporation. Eluent: Hexafluoroisopropanol / CHCl ₃ = 5/95 1 ml / min Sample: 100 ml of 1% solution Detection: UV 342 nm As a target sample (blank), tinuvin (TIN) was used.
PBT without UVIN) 213 (Comparative Example 1) was also analyzed. According to this, TINUVIN 213
In the system containing no (blank), almost no peak appears, but the tinuvin (TINUVIN) 2 of this reference example
Those containing 13 in the molecular chain show a peak with a distribution.
A GPC chart measured at 342 nm is shown in FIG.

The content of the UV stabilizer in the obtained polymer was quantified by proton-NMR (JSX GSX-400 nuclear magnetic resonance apparatus).
Were bound in the polymer (80% of the added 0.3 parts by weight are incorporated at the molecular ends of the polymer). Also, this polymer is used at a cylinder temperature of 260 ° C,
Injection molding at a mold temperature of 80 ℃, length 70 mm, width 35 m
A rectangular test piece having a thickness of m and a wall thickness of 1 mm was obtained, and the test piece was exposed to a weather meter for 100 hours and 200 hours under the following conditions, and a weather resistance test was performed. Weather meter: DEW cycle Sunshine weather meter Test condition: 60 minutes cycle (12 minutes shower ring) Light source: Carbon arc Upper SLE-U Lower SLE-L Temperature: 63 ° C ± 2 ° C The color tone (L value, a value, b value) is measured using a measurement color difference meter of Color Industry Co., Ltd.
The change rate (ΔE) of the color tone (L ₁ , a ₁ , b ₁ ) of the test piece after the exposure test with respect to the color tone (L ₀ , a ₀ , b ₀ ) of the test piece before the exposure test was calculated by the following formula.

[0030]

[Equation 1]

After 100 hours of exposure time, ΔE = 2.
After 4 and 200 hours, ΔE was 3.6. Further, using an injection molding machine (NISSEI FS-75), the polymer was molded into an ASTM test piece at a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C., and the tensile elongation at break was measured according to ASTM D638. Was 250%.

Reference Example 2 In the same manner as in Reference Example 1 , except that the addition amount of the ultraviolet stabilizer "Tinuvin 213" was changed from 0.3% by weight (based on the prepolymer) to 0.10% by weight (based on the prepolymer). Polybutylene terephthalate (η = 0.86) was obtained. Reference Example 3 In Reference Example 1 , the amount of the UV stabilizer "Tinuvin 213" added was 0.3% by weight (against the prepolymer) was 1.0% by weight.
Polybutylene terephthalate (η = 0.86) was obtained in the same manner except that the (prepolymer) was changed. Example 1 In Reference Example 1 , "Tinuvin 21" was used as an ultraviolet stabilizer.
Instead of 3 ”, the following formula (IX)

[0033]

[Chemical 9]

A compound having a hindered amine structure having a carboxylic acid ester group represented by "TINUVIN 770" manufactured by Ciba-Geigy Co., Ltd.
Polybutylene terephthalate (η = 0.85) was obtained in the same manner except that (trade name) was used . Example 2 In Reference Example 1 , the ultraviolet stabilizer "Tinuvin 213"
Instead of 0.3 wt% (to prepolymer), a mixture of "Tinuvin 213" 0.20 wt% (to prepolymer) and "Tinuvin 770" 0.10 wt% (to prepolymer) was used. Similarly, polybutylene terephthalate (η = 0.85) was obtained.

Comparative Example 1 Polybutylene terephthalate (η = 0.85) was obtained in the same manner as in Reference Example 1 , except that the ultraviolet stabilizer "Tinuvin 213" was not added. Comparative Example 2 100 parts by weight of polybutylene terephthalate having η of 0.7 obtained in Comparative Example 1 was added to Tinuvin (TI) as an ultraviolet stabilizer.
0.3 wt% of NUVIN) 213 was blended, and this was mixed using a Henschel mixer. This mixture was melt-kneaded at 260 ° C. using an extruder, extruded in a strand form from a die, and cut to obtain pellets. Using the pellets, test pieces for color tone and tensile elongation measurement were injection molded. In this pellet, tinuvin (TINUV
IN) 213 was contained in an amount of 0.3% by weight. This pellet was dissolved in a mixed solvent of hexafluoroisopropanol / chloroform = 2/3 in the same manner as the polymer of Reference Example 1 , methanol was added, the polymer was precipitated and filtered, and the ultraviolet stabilizer "Tinuvin in the methanol mother liquor was added. 21
Analysis of the amount of 3 "showed that the total amount of Tinuvin 2 in the mother liquor
13 were detected. This means that the polymerized polybutylene terephthalate is blended with a UV stabilizer having a hydroxyl group, and the two do not undergo an ester reaction even when melt-kneaded (the UV stabilizer is chemically bonded in the molecule of polybutylene terephthalate. Meaning). Comparative Example 3 In Comparative Example 2, TINUVIN 213
Instead of, a benzotriazole compound having a hydroxyl group represented by the following formula (X) [UV stabilizer of Shiraishi Calcium Co., Ltd., Cisoup UV5411 (trade name)]

[0036]

[Chemical 10]

Pellets were prepared in the same manner except that was used. It was confirmed that the polybutylene terephthalate and the UV stabilizer were not molecularly bonded to each other in the pellets.
Table 1 shows the physical properties of the obtained polymer and pellets.

[0038]

[Table 1]

[0039]

INDUSTRIAL APPLICABILITY The polybutylene terephthalate of the present invention, in which the functional group having an ultraviolet absorbing function is incorporated in the molecular chain, gives a molded article having excellent weather resistance and tensile elongation.

[Brief description of drawings]

FIG. 1 shows a GPC chart of polybutylene terephthalate obtained in Reference Example 1 at UV342 nm and a GPC chart of polybutylene terephthalate used in Comparative Example 1 at UV342 nm.

Continuation of front page (56) Reference JP-A-6-107805 (JP, A) JP-A-3-31235 (JP, A) JP-A-2-188581 (JP, A) JP-A-7-267937 (JP , A) JP-A-7-145246 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (2)

(57) [Claims] 1. A polyester comprising butylene terephthalate as a main repeating unit, wherein the polyester group has a carboxyl group or a hydroxyl group , and
Of 0.008 to 1.6 wt% with respect Chi terephthalate, selected from hydroxyl groups, compounds having Ruhi Ndadoami <br/> emissions based structure having a selected functional groups than carboxyl groups and carboxylic acid ester groups Polybutylene terephthalate having a structure in which the generated ultraviolet stabilizer is bound by an ester bond. 2. Mainly repeating butylene terephthalate
Polyester used as a unit
If the carboxyl group or hydroxyl group of the main chain is
0.008 to 1.6 weight to thylene terephthalate
% Of hydroxyl groups, carboxyl groups and carboxylic acids
Hindered amyl having functional group selected from ester group
Line of UV stabilizers selected from compounds with
Hydroxyl group, carboxyl group and carboxylic acid ester
Benzotriazole having functional group selected from ter group
UV stabilizers selected from the series of compounds form ester bonds
A more bonded structure of polybutylene terephthalate.