JPS586745B2 - Net Antica Polyester Materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyalkylene terephthalate composition that prevents thermal deterioration, and more specifically, is characterized in that a polyhydric alcohol diphosphite type compound and a monoalkylene dialkylphenol type compound are added together to polyester. The present invention relates to a thermally stabilized polyalkylene terephthalate composition.

Polyalkylene terephthalates are used in a variety of end applications as fibers, films and molded resin materials.

Polyethylene terephthalate has extremely excellent performance, especially as a material for fibers and films, and has become a main product in the textile industry.

Recently, a combination of polyethylene terephthalate and glass fiber has come to be used as a unique engineering plastic material as a molding resin material due to its extremely high heat distortion temperature and mechanical properties.

In addition, the general synthesis method of polyalkylene terephthalates such as polypropylene terephthalate and polybutylene terephthalate and their properties such as melting temperature and secondary transition temperature have already been described in J. G. J. Smith et al. Polmer Sci. 41851-59 (196
6), and these polymers appear to be more interesting as molding resin materials rather than as fibers.

That is, as estimated from the polymer structure, there is no problem of hygroscopicity compared to nylon resin, and the melting temperature and secondary transition temperature of this polymer are lower than that of polyethylene terephthalate, as described in the above literature. The crystallization temperature is lower than 29℃, and the second-order transition temperature is nearly 47℃ lower. Therefore, during injection molding, crystallization progresses sufficiently even at a low mold temperature, and polyethylene terephthalate is far superior to polyethylene terephthalate on the molding surface. This is because it is predicted that they will outperform.

In fact, polybutylene terephthalate/glass fiber resin has already been industrialized and commercially available as a molding resin material, and further development is expected.

However, a common drawback of polyalkylene terephthalates in general is that they are susceptible to moisture when melted at high temperatures and are susceptible to hydrolysis, resulting in a decrease in Cη during molding, which is a major problem.

This is particularly true for polyethylene terephthalate.

When it comes to polybutylene terephthalate, the decrease in [η] during melting is much smaller than that of PET.

Therefore, since the [η] of the molded product does not decrease significantly from the [η] during polymerization, the reduction in various properties of the molded product can be ignored.

However, polypropylene terephthalate and polybutylene terephthalate are mostly applied as engineering plastics that have extremely high heat distortion temperatures by adding reinforcing agents such as glass fibers, so it is natural that polypropylene terephthalate and polybutylene terephthalate can be used at temperatures above room temperature or 100 to 200°C. It is expected that it will be used at high temperatures.

According to the results of studies conducted by the inventors, if glass-reinforced polybutylene terephthalate or polyethylene terephthalate is molded and the molded product is left at, for example, 180°C, deterioration occurs within 2 to 5 days, discoloration occurs, and the strength decreases to 1% of its original value. It was observed that the value decreased to /2 or less.

It has been found that lowering the service temperature below this results in retention of strength for a somewhat longer period of time, but essentially a significant decrease in strength.

Even attempts to change the polymerization conditions during polymer production or to improve the degree of polymerization have not had any particular effect.

In this way, the deterioration of polyalkylene terephthalate is
Two types of deterioration can be considered: one that occurs during melt molding, and one that gradually deteriorates when the molded product is left at a high temperature below its melting point for a long time.

Although the present invention particularly relates to the latter, it also has significant effects on the former.

The linear polyester has a general formula (wherein, Indicates an organic group selected from cycloalkyl groups.

) and a polyhydric alcohol diphosphite type compound represented by the general formula (where R, R', R1, R2, R3 and R4 are each a hydrogen atom or a linear or branched aliphatic or aromatic residue). Show the basics.

) By adding 0.01 to 1% by weight of each monoalkylenedialkylphenol to the polyester, it is possible to maintain its performance extremely stably even when exposed to high temperatures in the air for a long time. A composition is provided.

In (■), R1 and R2 are alkyl, alkenyl,
1 selected from allyl, aralyl, and cycloalkyl groups
Denotes an organic group having ~32 carbon atoms.

X represents a tetrahydric alcohol residue selected from sorbitol, pentaerythritol, and dipentaerythritol.

In (n), R, R', and R1 to R4 represent hydrogen or a linear or branched aliphatic or aromatic residue.

(I), the compound of (I) was mixed with the polyalkylene terephthalate, and the compound of (I) was mixed with the polyalkylene terephthalate. 0.1-0.
It is preferable to add 5 wt%.

In this case, if the amount added exceeds 1%, the thermal stability itself will improve, but the strength of the polyalkylene terephthalate molded product itself will decrease, which is not preferable.
If the amount is less than that, the desired effect of the present invention will no longer be obtained.

Further, when (I) is added alone, an effect can be obtained in terms of heat aging resistance by increasing the amount added, but if it is added until the effect is clearly evident, the physical properties of the composition will deteriorate, which is not preferable.

Moreover, even if the compound (n) is added alone and the amount is increased, the effect will be small, and if it is left at high temperature, coloring will occur over time, which is not preferable.

The object of the present invention is achieved only when (I) and (n) are used together.

The method of adding these compounds is not particularly limited, but they can be added after the condensation reaction of polyalkylene terephthalate is completed, or polyalkylene terephthalate chips and these compounds may be mixed in a V-type blender or the like, and the mixture may be fed into the hopper of an extruder and extruded. Possible methods include a method in which chips and compounds are continuously added to the extruder hopper from a separate metered feeder.

In addition, the compound of the present invention can be added to the above-mentioned polyalkylene terephthalate alone, as well as other flame retardants,
Coloring agents and reinforcing agents and fillers such as talc, glass fibers, glass beads, carbon fibers, etc. can be used together.

This will be explained in detail below using examples.

Example 1 25 in a mixed solvent of equal amounts of tetrachloroethane and phenol
The following compound, distearyl pentaerythritol diphosphite (compound ( A); hereinafter abbreviated as (A)), 4-4'
0.15 wt% of butylidene bis(t-butyl 3-methyl)phenol (compound (a); hereinafter abbreviated as (a)) was added to polybutylene terephthalate, and V
Mix for 5 minutes with a mold blender, and mix this mixture with a 40mmψ
Pour into the hopper of a vented extruder and set the cylinder temperature to 23.
It was extruded at 0 to 255°C and shaped into pellets.

The resulting pellets, after drying, weighed 5 oz.
Using a ψ in-line screw type injection molding machine, the cylinder temperature was 250℃, the mold temperature was 60℃, and the injection pressure was 600℃.
kg/cm2, 3.2mm thick J with a molding cycle of 60 seconds
An injection molded product was formed using an ISI dumbbell and three heat deformation temperature test pieces of 3.2 and 6.4 mm thickness and a mold, and tensile strength, bending strength, HDT, etc. were measured.

The results are shown in Table 2.

The thermal oxidative deterioration resistance in Table 2 was conducted under accelerated conditions of 200°C.

Comparative Example 1 consists of 7 kg of polybutylene terephthalate and 3 kg of glass fiber, which are exactly the same as in Example 1, and are completely the same as in Example 1 except that they do not contain compounds (A) and (a). The composition and Example 1
It was molded and evaluated in exactly the same way.

From the above results, the effect of the stabilizer of this example is clear.

In addition, the compositions of Example 1 and Comparative Example 1 were heated at 27°C at a temperature of 27°C.
It was injection molded at 0,290,310°C and its bending strength was measured.

The results are shown in Table 3.

Table 3 also shows the results of measuring the polymer viscosity [η] of the molded product when molded at a cylinder temperature of 310°C.

As is clear from this example, the compound of the present invention is also effective in preventing a decrease in the degree of polymerization during high-temperature melting of polyester.

Examples 2 to 5, Comparative Examples 2 to 7 7 kg of polybutylene terephthalate with [η] of 0.93
Compound (A) and compound (a) were added to 3 kg of glass fiber in the composition shown in Table-4, and extrusion was carried out in the same manner as in Example 1 except that the amounts of these compounds were different. , was molded and evaluated.

In addition, Comparative Examples 2 to 7 show compounds (
A) and compound (a) were used alone.

Note that the heat resistance in Table-4 was conducted under accelerated conditions of 200°C, and the bending strength was 50% of the initial value.
It shows the number of days until it reaches %.

The same applies to the heat resistance in the following Examples and Comparative Examples.

As is clear from this table, when compound (A) is added alone, it has an effect on heat resistance, but the initial physical properties deteriorate.

On the other hand, when compound (a) is added alone, the physical properties of compound (a) 1
% addition, the heat resistance does not decrease, but the heat resistance improves somewhat.

However, even if 0.5% or more is added, the effect is saturated and the color changes to brown after 1 to 2 days, which is not preferable.

The effectiveness of the combination system is clear.

Example 6 The following compounds were used in place of the two compounds used in Example 1, and the same study was conducted to show the results.

The amount added is 0.15% based on PBT.

Polyhydric alcohol diphosphite monoalkylene dialkyl phenol comparative example 8 The following stabilizer was added instead of polyhydric alcohol diphosphite and the results were investigated in the same manner as in Example 1.Ta
Shown in ble6.

It was found that there was almost no effect on heat resistance.

Example 7 Using polyethylene terephthalate instead of polybutylene terephthalate in Example 1, molding was performed at a cylinder temperature of 270°C and a mold temperature of 140°C, and heat resistance was evaluated.

The results are shown in Table 7.

Moreover, Comparative Example 9 is a case where the compound of the present invention is not added.

This result shows that the composition of the present invention has extremely excellent heat resistance.

Claims (1)

[Claims] (However, X is sorbitol, pentaerythritol,
It represents a tetrahydric alcohol residue selected from dipentaerythritol, and R1 and R2 each represent an organic group selected from alkyl, alkenyl, allyl, aralyl, and cycloalkyl groups having 1 to 32 carbon atoms. ) and a polyhydric alcohol diphosphite type compound represented by the general formula (where R, R', R1, R2, R3 and R4 are each a hydrogen atom or a linear or branched aliphatic or aromatic residue). A heat-stabilized polyester composition characterized in that 0.01 to 1% by weight of monoalkylenedialkylphenols represented by the following formulas are added to the polyester.