JPS5844095B2 - Polyethylene terephthalate composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyethylene terephthalate composition having excellent moldability.

Although polyethylene terephthalate generally has excellent physical and mechanical properties, it has not been widely used in the field of molding materials.

The main reason for this is the poor moldability of polyethylene terephthalate, and when the molecular weight is relatively low, the melt viscosity becomes extremely low, making it difficult to mold using a normal molding machine.

For this reason, studies are being conducted to increase the degree of condensation of polyethylene terephthalate to increase its molecular weight, but if high-temperature melt polycondensation is used, thermal decomposition of the polymer will compete with the polycondensation reaction, making it difficult to obtain a high molecular weight product. is difficult.

Therefore, generally, a method is used to perform solid phase polymerization while suppressing thermal decomposition by lowering the reaction temperature, but in this case, it is necessary to distill off the free gas generated by the reaction from the solid phase.
Moreover, since polycondensation is required for an extremely long time, the manufacturing cost increases significantly.

In view of the current situation, the inventors of the present invention have conducted intensive research on a simple and economical method of thickening polyethylene terephthalate, and have found that a small amount of a modifying agent obtained by reacting a specific epoxy compound with an organic carboxylic acid is added to polyethylene terephthalate. It has become clear that the desired composition can be easily obtained by adding it to terephthalate and melting and kneading it.

Here, the specific epoxy compound is one having an incyanurate i or triazine ring ester structure, and has a remarkable thickening effect on polyethylene terephthalate, but if this epoxy compound is used alone, it may cause problems during melt-kneading. It is not suitable for practical use because insolubilization occurs.

In order to improve this point, it is effective to use an organic compound having an appropriate functional group such as a carboxyl group, amine group, incyanate group, or hydroxyl group in combination with the above epoxy compound. Polyethylene terephthalate with high polyethylene terephthalate can be stably obtained.

However, the composition obtained by directly adding the above-mentioned epoxy compound and functional organic compound to polyethylene terephthalate has a high viscosity and is stabilized, but it is said that fish eyes occur especially when molded into a film or sheet. It is difficult to say that it is necessarily satisfactory because it has some shortcomings.

Therefore, as a result of conducting more detailed research on improving this point, we found that the above epoxy compound and a functional organic compound, especially an aromatic carboxylic acid or anhydride, were melt-reacted in advance, and then added to polyethylene terephthalate and kneaded. The present invention was completed by discovering that a composition with extremely low fish eyes can be stably obtained when formed into a film or sheet with a high viscosity.

That is, the gist of the present invention is to provide an epoxy compound A having an incyanurate ring or triazine ring ester structure.
Modification obtained by melting and reacting aromatic carboxylic acid or anhydride B of the acid at a molar ratio of B/A of 0.5 to 2.0 at a temperature of 100 to 200°C for 5 to 30 minutes. In a composition consisting of agent C and polyethylene terephthalate, the epoxy compound A0.000 based on the amount charged
The composition consists of Modifier C corresponding to 5 to 0.02 mol and 100 g of polyethylene terephthalate.

The epoxy compound used in the present invention has an incyanurate i or triazine ring ester structure, and specifically, triglycidyl isocyanurate,
Triglycidyl cyanurate, N-methyl-N', N
Examples include -diglycidyl isocyanate.

The functional organic compound used in combination is preferably an aromatic carboxylic acid, and examples thereof include aromatic monocarboxylic acids such as benzoic acid, toluic acid, dimethylbenzoic acid, and ethylbenzoic acid, and aromatic dicarboxylic acids such as phthalic acid. Acid anhydrides such as benzoic anhydride and phthalic anhydride are also effective as carboxylic acid derivatives.

It is an essential requirement of the present invention that the additive modifier of the present invention is obtained by melt-reacting an epoxy compound and an aromatic carboxylic acid or an acid anhydride in advance.

Here, the aromatic carboxylic acid is preferably reacted at a molar ratio of 0.5 to 2 with respect to the epoxy compound. If the molar ratio is less than 0.5, the melt viscosity of polyethylene terephthalate becomes unstable and insolubilization occurs. , and if it exceeds 2, the thickening effect decreases, which is inappropriate.

The reaction to obtain these modifiers is achieved by charging a predetermined amount of the epoxy compound and aromatic carboxylic acid or acid anhydride into a container equipped with a cooling tube, and melting and stirring at 100 to 200°C for 5 to 30 minutes. .

If the reaction temperature is lower than 100'C, the reaction becomes non-uniform and requires a long reaction time, and if it is higher than 200'C, bonds between epoxy groups and by-products are formed, resulting in coloring of the modifier. This is not desirable as it may cause injury.

Regarding the reaction time, if the reaction time is shorter than 5 minutes, the reaction will not be sufficient, but the reaction between the epoxy group and the carboxyl group will almost reach an equilibrium state in about 30 minutes.

Therefore, even if the reaction is allowed to take longer than 30 minutes, there is no particular effect and, in fact, coloring is more likely to occur, which is not preferable.

When the reaction is carried out at a relatively high temperature for a long time, it is effective to carry out the melting reaction in a nitrogen or other inert gas stream in order to suppress inferiority and coloration of the reactant.

The molten reaction product thus obtained is preferably added to and mixed with polyethylene terephthalate as quickly as possible without cooling and solidifying.

A reactant solidified by cooling is unsuitable because it reduces the uniformity of mixing with polyethylene terephthalate, makes the thickening effect unstable, and increases the occurrence of fish eyes in film/sheet molded products.

If the molten reactant is easily solidified by cooling or is viscous,
It is preferable to use an appropriate diluting solvent in order to improve the uniformity of mixing with polyethylene terephthalate.

The diluting solvent is preferably one that is inert to the thickening reaction of polyethylene terephthalate caused by a modifier, and specific examples include chloroform, dichloroethane, tetrachloroethane, dioxane epichlorohydrin, acetonitrile, dimethylformamide, dimethyl sulfoxide, and the like.

It is preferable to add these diluting solvents after the melting reaction between the epoxy compound and the aromatic carboxylic acid or acid anhydride is completed; however, if the temperature of the reactants is higher than the boiling point of the diluting solvent used, Cool before adding.

The amount of modifier added is polyethylene terephthalate 1
0.0.9, the epoxy compound is 0.9 based on the amount charged before the melt reaction with the aromatic carboxylic acid or acid anhydride.
The amount is preferably in the range of 0.0005 to 0.02 mol.

If it is less than 0.0005 mol, the thickening effect will be low;
If the amount exceeds 0.02 mol, insolubilization and coloring will occur during kneading, and the number of fish eyes in the film/sheet molded product will increase, so it is unsuitable.

When using a diluting solvent, the amount added depends on the viscosity and amount of the molten reaction product of the epoxy compound and aromatic carboxylic acid or acid anhydride, and cannot be uniformly limited, but it is generally 0.
2 to 1.5% by weight is suitable.

The modifier and polyethylene terephthalate obtained by the melt reaction are mixed uniformly in a suitable mixer such as a tumbler, and then subjected to melt kneading.

As the melt mixing device, any commonly used device such as a Panbury mixer, a Farrel mixer, an extruder, etc. can be used, but an extruder is particularly preferred from the viewpoint of process simplicity.

When using an extruder, once the pellets have been thickened and made to have a high molecular weight, the pellets can be subjected to injection, blowing, sheet bottom shaping, etc.; It is also possible.

Although the shape of the extruder is not particularly limited, a vent-type extruder is suitable since it allows degassing and removal of diluting solvent, moisture, unreacted modifier, and other volatile by-products.

In addition, as extrusion conditions, a range of 265 to 300° C. and an average residence time of 2 to 10 minutes is appropriate.

Also, during extrusion, it is preferable to use a hopper sealed with nitrogen. By extruding under a nitrogen atmosphere, deterioration and coloring of the polymer attached to the screw and barrel is suppressed, and even after long-term continuous operation, no deterioration occurs in the discharged polymer. Contamination with other substances or colored substances will no longer be recognized.

The polyethylene terephthalate used in the present invention is a polyester in which 80 mol% or more of the repeating units are ethylene terephthalate units, and it may be copolymerized with a conventionally known acid component or oxy component to the extent that the purpose of the present invention is not impaired. There is no problem in adding coloring inhibitors, heat resistant agents, matting agents, and flame retardants.

The degree of condensation of the polyethylene terephthalate used is not particularly limited.

The present invention will be explained in more detail with reference to Examples below.

The melt index (MI), which is a standard for comparing melt viscosity, is determined by vacuum drying the pellets at 160°C for 24 hours and then drying them at 265°C for 2
．． Measured according to ASTM D-1238 under 8-load.

Example I A. Preparation of Modifier 85 g of triglycidyl isocyanurate (TGIC) and 34 g of benzoic acid (BA) were placed in a 500 CC four-piece separable flask equipped with a stirring rod, cooling tube, nitrogen introduction tube, and solvent dropping tube. ．． ! i'(
A molar ratio of 1/1) was added and the atmosphere was replaced with nitrogen for 1 minute.

Next, place the moparable flask in a 120°C oil bath,
After TGIC and BA are melted by stirring in a nitrogen stream"5
Allowed to react for minutes.

After the reaction was completed, 109 g of tetrachloroethane (TCE) kept in ice was added dropwise and stirred for 2 minutes to obtain a colorless and transparent modifier solution.

B, Extrusion of modified polyethylene terephthalate Obtained by condensation of terephthalic acid and ethylene glycol, intrinsic viscosity 0.71 (phenol/tetrachloroethane 5015
Polyethylene terephthalate (P
Immediately after pre-drying 5 kg of ET) at 80°C, 679 g of the above modification solution was added and mixed for 5 minutes in a tumbler to obtain a raw material mixture.

In the raw material mixture, the amount of TGIC added to 100 g of PET was 0.0017 mol, the molar ratio of BA to TGIC was BA/TGIC=1/1, and the amount of TCE added to PET was 0.64% by weight.

Next, the raw material mixture was heated to 30vL11Lφ with L/D=25.
The polymer was fed into a nitrogen-sealed hopper of a vent extruder, melted and kneaded under the conditions of a temperature of 275°C and an average residence time of 5 minutes, and the polymer was discharged from a T-shaped die with a thickness of 1 mm and pulled at a speed of 4 doors/second. A sheet with a thickness of 0.3 mm was obtained.

No drawdown phenomenon was observed in the discharged polymer, and the obtained sheet was transparent and uniform, and no fish eyes were observed.

When the obtained sheet was cut into pieces and the MI was measured, it was 32.9.
It was 710 minutes.

Comparative Example 1 When the same PET used in Example 1 was directly extruded without adding a modifier, the extruded polymer had a significant drawdown and could not be drawn into a sheet.

I measured the MI of the discharged polymer just to be sure, but it was 126g.
It showed a large value of 710 minutes.

Comparative Example 2 For the same PETlOI used in Example 1, T
When a tri-blend of GIC powder at a ratio of 0.0017 mol was used as a raw material mixture and extruded in the same manner as in Example 1, the melt viscosity of the extruded polymer was unstable, and the viscosity gradually increased until finally Insolubilization occurred and extrusion became impossible.

Comparative Example 3 For 100g of the same PET used in Example 1,
A tri-blend of TGIC powder and BA powder in a ratio of 0.0017 mol each was used as a raw material mixture, and extrusion was performed in the same manner as in Example 1.

Although the discharged polymer showed stable melt viscosity without drawdown and a sheet with a thickness of 0.32 mm was obtained, the sheet had noticeable fish eyes.

The MI measured from a strip of the sheet was 29 g/l 0
It was a minute.

Example 2 Modified PET was extruded to form a sheet in the same manner as in Example 1 except that the blending conditions of the modifier were changed.

Table 1 shows the relationship between the compounding conditions of the depressant and the MI and fish eye of the obtained sheet.

As the amount of BA added increases and the reaction temperature rises, M
Although there was a tendency for I to increase, the sheet moldability was generally good, the melt viscosity was stable, and the sheet was transparent and uniform without fish eyes.

Comparative Example 4 Except for using a modifier prepared under the conditions shown in Table-2,
Modified PET was extruded into a sheet in the same manner as in Example 1.

As is clear from the results in Table 2 compared with Table 1 (Example 2), when the BA/TGIC molar ratio is smaller than 0.5, insolubilization occurs, and when it is larger than 2, the melt viscosity is low and drawdown occurs. This is inappropriate because it may cause injury.

If the reaction temperature is lower than 100+*0C, MI will be unstable and fish eyes will occur, and if it is higher than 200C, the sheet will be colored.

If the reaction time exceeds 30 minutes, although there is no significant difference in MI, the sheet becomes colored, which is not preferable.

Therefore, this table shows that the preferred conditions for preparing the modifier are a BA/TGIC molar ratio of 0.5 to 2.01, a reaction degree of 100 to 200 DEG C., and a reaction time of 5 to 30 minutes.

Example 3 Using the modifier solution prepared in Example 1, the amount of TGIC added to PET10 (Bi') was 0.0005 mol, 0.005 mol, and 0.02 mol based on the amount of TGIC charged before melt reaction. A raw material mixture was prepared in such a proportion that the modified PET was extruded into a sheet.

However, the experiment was conducted under the same conditions as in Example 1 except for the amount of the modifier solution added.

In either case, the melt viscosity of the discharged polymer was stable, and a transparent and uniform sheet was obtained.

The physical properties of the sheet are shown in Table 3.

Comparative Example 5 Same as Example 3 except that TG for 100g of PET
Experiments were conducted for cases where the amount of IC added was 0.0003 mol and 0.025 mol.

The results are also listed in Table-3.

Example 4 As an epoxy compound used as a modifier, triglycidyl cyanurate and N were used instead of TGIC.
Sheet extrusion of modified PET was carried out in the same manner as in Example 1 except that -methyl-N',N//-diglycidyl isocyanurate was used.

In either case, the discharged polymer had a high viscosity and was stable, and the resulting sheet was transparent and uniform, with no fish eyes observed.

The MI measured from the sheet strips was 28 g/10 minutes and 26 g/l 0 minutes, respectively.

Example 5 A sheet of modified PET was extruded in the same manner as in Example 1, except that benzoic anhydride and phthalic anhydride were used instead of BA as the aromatic carboxylic acid used as the modifier.

In either case, the discharged polymer had a high viscosity and was stable, and the resulting sheet was transparent and uniform, with no fish eyes observed.

The MI measured from the sheet strips was 33 g/10 minutes and 37 g/10 minutes, respectively.

Claims (1)

[Claims] 1 Epoxy compound A having an isocyanurate ring or triazine ring ester structure and aromatic carboxylic acid or anhydride B of the acid are heated at 100 to 200°C at a molar ratio of B/A of 0.5 to 2.0. In a composition consisting of Modifier C and polyethylene terephthalate obtained by melting reaction at a temperature of 5 to 30 minutes, Modifier C corresponds to 0.0005 to 0.02 mole of epoxy compound A based on the amount charged. and polyethylene terephthalate IoOg.