KR20000007657A - Polycarbonate resin composition - Google Patents

Abstract

PURPOSE: A composition comprising a)polycarbonate as a main component, b)tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane or octadecyl-3-(3,5)-di-t-butyl-4-hydroxyphenyl)propionate as a primary antioxidant and bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite is provided which has good high temperature heat resistance and transparency. CONSTITUTION: The composition comprises 100 wt. parts of polycarbonate with a melting flow index of 1-15g/10 min and a density of 1,200-1,215, 0.02-0.18 wt. parts of tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane or octadecyl-3-(3,5)-di-t-butyl-4-hydroxyphenyl)propionate and 0.02-0.18 wt. parts of bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite. It has a good high temperature heat resistance, antiyellowing and transparency and it also can be effectively used for a product using for a long term at a high temperature.

Description

Polycarbonate Resin Composition

The present invention relates to a polycarbonate resin composition, and more particularly, to a polycarbonate resin composition useful for transparent applications, particularly for products that can be used for a long time at a high temperature due to good high temperature heat resistance, long term heat resistance, yellowing resistance and transparency.

Polycarbonate is an excellent engineering plastic with good transparency, mechanical properties, dimensional stability, electrical properties, and dimensional stability, and has been used in various fields.

In general, polycarbonate has excellent heat resistance, but when used for applications requiring transparency, it should be particularly excellent in yellowing resistance and long term heat resistance. However, when processing above the melting temperature or long-term use at a high temperature near the glass transition temperature, there is a problem that yellowing phenomenon occurs and the heat resistance is lowered.

Therefore, in order to improve this, generally, an organic phosphite-based or phosphonite-based compound is added as a heat stabilizer to prepare a polycarbonate resin. In this case, a phosphite-based compound is added alone or an organic phosphite- and phenol-based The heat stabilizer is mixed and added, and sometimes a small amount of epoxy compound is added to improve the yellowing resistance and the heat resistance of the resin.

However, phenolic antioxidants are rarely used because they form a yellow chromophore by the binding reaction of two molecules of phenolate when used alone. This phenomenon is further exacerbated at a high temperature near 300 ° C. at which polycarbonate is processed.

Specific examples of the organic phosphite thermal stabilizer include tris (nonylphenyl) phosphite, distearylpentaerythritol diphosphite, tris (2,4-di-t-butylphenyl) -phosphite or bis (2,6-di -t-butyl-4-methylphenyl) pentaerythritol diphosphite and the like.

Specific examples of the phenolic heat stabilizer used in combination with the above organic phosphite heat stabilizer include 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-sec- Butylphenol or octadecyl-3- (3,5, -di-t-butyl-4-hydroxyphenyl) propionate and the like.

In general, when the amount of these thermal stabilizers is less than 0.1 parts by weight based on the total resin composition, the thermal stability is poor rather than the addition of these, and yellowing occurs. This phenomenon is mainly caused by tris (2,4-di-t-butylphenyl) -phosphite or tetrakis- (2,4-di-t-butyl-phenyl) -4 having a large amount of phenolate among phosphite-based heat stabilizers. , 4'-bisphenylene diphosphite and the like.

The molar ratio of these intramolecular phenolates / phosphorus component is 3 and 2, respectively.

On the other hand, when the amount of the phosphite-based heat stabilizer is more than 1.0 parts by weight relative to the total resin composition, there is little increase in the effect of the addition of the heat stabilizer, which is uneconomical and reduces the overall physical properties such as impact resistance and transparency. have.

When kneading extrusion production of thermoplastic resin compositions including these, or during extrusion and injection processing for molding processing, it is required to have a high temperature of 280 to 320 ° C. At this time, the thermal stability of the thermal stabilizer itself is not sufficiently good, in particular, low molecular weight. The heat stabilizer is relatively volatile, and part of the heat stabilizer may be removed out of the resin by the vacuum accompanying the extrusion process.

Therefore, in the case of opaque products such as colored resins, resin mixtures or reinforced resins, even if the yellowing phenomenon to some extent does not significantly change the color and appearance of the product, such a thermal stabilizer can be generally used, but transparent In particular, it is difficult to improve the thermal stability or the yellowing resistance of polycarbonate resins by using these heat stabilizers when the slight yellowing phenomenon can affect the appearance of the product as in a product used for a long time at high temperature.

It is an object of the present invention to provide a polycarbonate resin composition having excellent thermal stability and yellowing resistance even when used at a high temperature for a long time by using a mixture of a phosphite-based and phenol-based thermal stabilizer having a high molecular weight, a low volatility, and a high pyrolysis temperature. have.

Polycarbonate resin composition of the present invention for achieving this purpose is 100 parts by weight of polycarbonate resin, tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane or octadecyl-3 0.02 to 0.18 parts by weight of-(3,5-di-t-butyl-4-hydroxyphenyl) propionate and bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite 0.02 It is characterized by consisting of-0.18 parts by weight.

The present invention will be described in more detail as follows.

The phosphite thermal stabilizer used in the present invention is bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, and the phenolic thermal stabilizer is octadecyl-3- (3,5, -di -t-butyl-4-hydroxyphenyl) propionate and tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane with high molecular weight, low volatility and high pyrolysis temperature to be.

Octanesyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate and tetrakisethylene (3,5-di-t-butyl-4- hydride in phenolic heat stabilizers Oxyhydrocinnamate) methanes may be used alone or in combination.

The amount of the phosphite thermal stabilizer and the phenol thermal stabilizer added is preferably 0.02 to 0.18 parts by weight based on 100 parts by weight of the polycarbonate resin.

If the content of the phosphite thermal stabilizer exceeds 0.2 parts by weight outside of the above range, the effect of improving the thermal stability is not greatly improved, and if excessively excessively added, the physical properties are reduced. If the content of the phenolic heat stabilizer is out of the above range, the effect of thermal stability is not improved, too, and there is a problem that the possibility of discoloration to yellow increases.

These heat stabilizers are melt mixed in the actual resin manufacturing process in the extrusion process after polycarbonate resin polymerization or the compounding extrusion process of polycarbonate, and other additives such as a release agent or a lubricant may be added depending on the use and need.

The present invention relates in particular to polycarbonates having excellent yellowing resistance and thermal stability, wherein the thermal stabilizers are added by a solution casting method.

On the other hand, the polycarbonate resin used in the present invention is a bisphenol A having a melt flow index of 2 to 15 g / 10 minutes measured by the ASTM D-1238 method and a density of 1.200 to 1.215 g / cm 3 measured by the ASTM D-792 method. And polycarbonate polymerized from phosgene.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Example 1

0.02 part by weight of tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane and 100 parts by weight of polycarbonate resin and bis (2,6-di-t-butyl-4-methylphenyl) 0.18 parts by weight of pentaerythritol diphosphite was added and dissolved in a methylene chloride solvent. Then, a film was prepared by a film casting method, which was then heated in a forced-circulation oven at 300 ° C. for 1 hour to measure properties. The results are shown in Table 1 below. Indicated.

Example 2

0.06 parts by weight of tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane and 100 parts by weight of polycarbonate resin and bis (2,6-di-t-butyl-4-methylphenyl) 0.14 parts by weight of pentaerythritol diphosphite was added to prepare a film in the same manner as in Example 1.

Example 3

0.1 parts by weight of tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane and 100 parts by weight of polycarbonate resin and bis (2,6-di-t-butyl-4-methylphenyl) 0.1 parts by weight of pentaerythritol diphosphite was added to prepare a film in the same manner as in Example 1.

Example 4

0.14 parts of tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane and 100 parts by weight of polycarbonate resin and bis (2,6-di-t-butyl-4-methylphenyl) A film was prepared in the same manner as in Example 1 by adding 0.06 parts by weight of pentaerythritol diphosphite.

Example 5

0.18 parts by weight of tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane and 100 parts by weight of polycarbonate resin and bis (2,6-di-t-butyl-4-methylphenyl) A film was prepared in the same manner as in Example 1 by adding 0.02 parts by weight of pentaerythritol diphosphite.

Example 6

0.14 parts by weight of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate and 100 parts by weight of polycarbonate resin and bis (2,6-di-t-butyl-4- Methylphenyl) pentaerythritol diphosphite 0.06 parts by weight was added to prepare a film in the same manner as in Example 1.

Example 7

0.1 part by weight of octadecyl-3- (3,5, -di-t-butyl-4-hydroxyphenyl) propionate and 100 parts by weight of polycarbonate resin and bis (2,6-di-tert-butyl- 4-methylphenyl) pentaerythritol diphosphite 0.1 part by weight was added to prepare a film in the same manner as in Example 1.

Example 8

0.06 parts by weight of octadecyl-3- (3,5, -di-t-butyl-4-hydroxyphenyl) propionate and 100 parts by weight of polycarbonate resin and bis (2,6-di-tert-butyl- 4-methylphenyl) pentaerythritol diphosphite 0.14 parts by weight was added to prepare a film in the same manner as in Example 1.

Example 9

0.1 parts by weight of tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane and 100 parts by weight of polycarbonate resin and bis (2,6-di-t-butyl-4-methylphenyl) 0.1 parts by weight of pentaerythritol diphosphite was added thereto, and a film was prepared in the same manner as in Example 1, and then heated at 140 ° C. for 30 days, and then the light transmittance was measured.

Example 10

0.1 part by weight of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate and 100 parts by weight of polycarbonate resin and bis (2,6-di-t-butyl-4- 0.1 parts by weight of methylphenyl) pentaerythritol diphosphite was added and prepared in the same manner as in Example 1, and heated at 140 ° C. for 30 days to measure light transmittance.

Comparative Example 1

The film was prepared in the same manner as in Example 1 using only polycarbonate resin.

Comparative Example 2

0.2 parts by weight of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate was added to 100 parts by weight of polycarbonate resin to prepare a film in the same manner as in Example 1.

Comparative Example 3

0.2 parts by weight of bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite was added to 100 parts by weight of polycarbonate resin to prepare a film in the same manner as in Example 1.

Comparative Example 4

0.2 parts by weight of tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane was added to 100 parts by weight of polycarbonate resin to prepare a film in the same manner as in Example 1.

Comparative Example 5

The polycarbonate resin containing no heat stabilizer was prepared in the same manner as in Example 1 and heated at 140 ° C. for 30 days to measure light transmittance.

Comparative Example 6

0.2 parts by weight of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate was added to 100 parts by weight of polycarbonate resin, and a film was produced in the same manner as in Example 1, 140. The light transmittance was measured after heating at 30 ° C. for 30 days.

Comparative Example 7

0.2 parts by weight of bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite was added to 100 parts by weight of polycarbonate resin, and a film was prepared in the same manner as in Example 1 for 30 days at 140 ° C. After heating, the light transmittance was measured by the above method.

Comparative Example 8

0.2 parts by weight of tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane was added to 100 parts by weight of polycarbonate resin, and a film was prepared in the same manner as in Example 1, at 140 ° C. After heating for 30 days, the light transmittance was measured by the above method.

(Unit: parts by weight) Polycarbonate resin Tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane Octadecyl-3- (3,5-di-t-butyl-hydroxyphenyl) propionate Bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite Example One 100 0.02 - 0.18 2 0.06 - 0.14 3 0.1 - 0.1 4 0.14 - 0.06 5 0.18 - 0.02 6 - 0.14 0.06 7 - 0.1 0.1 8 - 0.06 0.14 9 0.1 - 0.1 10 - 0.1 0.1 Comparative example One 100 - - - 2 - 0.2 - 3 - - 0.2 4 0.2 - - 5 - - - 6 - 0.2 - 7 - - 0.2 8 0.2 - -

Experimental Example

Polycarbonate film prepared according to the above Examples and Comparative Examples is a sample for measuring the yellowing index, light transmittance and molecular weight distribution, the film casting method from a methylene chloride solution containing a polycarbonate resin composition of 10% by weight at 25 ℃ The thickness was about 10 microns and it was heated in a forced circulation oven and evaluated according to the following measurement method.

(Assessment Methods)

1.Yellow Index: A solution dissolved in methylene chloride, measured according to ASTM D1925-63J.

2. Light transmittance: The light transmittance of 425 nm wavelength light beam was measured with the ultraviolet spectrometer.

3. Weight average molecular weight (Mw) and molecular weight distribution: It measured by the gel permeation chromatography method (GPC) corrected with the polystyrene standard sample using the tetrahydrofuran solution of polycarbonate.

The results are as shown in Table 2 and Table 3, respectively.

Yellowness Index (YI) Weight average molecular weight (Mw) Molecular Weight Distribution (Mw / Mn) Example One 35.4 47,300 2.15 2 29.0 38,300 2.28 3 33.8 55,200 2.45 4 31.5 62,000 2.91 5 41.0 26,100 2.93 6 26.3 44,800 1.70 7 28.5 41,500 1.67 8 28.6 39,800 1.62 Comparative example One 42.1 122,500 3.82 2 35.5 72,800 3.04 3 28.4 54,600 2.01 4 52.2 38,500 2.84

Light transmittance (%) Weight average molecular weight (Mw) Molecular Weight Distribution (Mw / Mn) Example 9 76 37,000 1.83 Example 10 75 37,000 1.63 Comparative Example 5 71 39,800 1.80 Comparative Example 6 71 39,200 1.71 Comparative Example 7 78 41,100 1.79 Comparative Example 8 72 41,000 1.79

From the results of Tables 1 and 2, the polycarbonate resin composition according to the present invention is light according to the heat and long-term heat resistance that is considered important in the product application of polycarbonate as compared to the resin composition using a single compound as a heat stabilizer according to the comparative example It can be seen that the product characteristics are excellent, such as excellent permeability and yellowing resistance, and maintenance of molecular weight and molecular weight distribution.

As described in detail above, tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane or octadecyl-3- (3,5-di- as a heat stabilizer according to the present invention. prepared by mixing a phenolic compound such as t-butyl-4-hydroxyphenyl) propionate and a phosphite compound such as bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite The polycarbonate resin composition has good high temperature heat resistance, long term heat resistance, yellowing resistance and transparency, and thus can be usefully used for transparent applications, especially for products used for a long time at high temperature.

Claims (2)

100 parts by weight of polycarbonate resin, tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane or octadecyl-3- (3,5-di-t-butyl-4-hydroxy Roxyphenyl) propionate polycarbonate resin composition consisting of 0.02 to 0.18 parts by weight and bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite 0.02 to 0.18 parts by weight. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin has a melt flow index of 2 to 15 g / 10 minutes and a density of 1.200 to 1.215 g / cm 3.