JPS6032813A - Modified saturated polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the titled composition giving a molded article having improved heat resistance without lowering the transparency, by mixing a saturated polyester resin with a compound having plural methacryloyl groups, and irradiating the mixture with ionizing radiation. CONSTITUTION:The objective composition is prepared by mixing 100pts.wt. of a saturated polyester resin such as polyethylene terephthalate with preferably 1-10pts.wt. of a compound having >=2 methacryloyl groups (preferably trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, or tetramethylolmethane tetramethacrylate), and irradiating the resultant mixture with ionizing radiation under a condition to give absorbed dose of 1-60Mrad.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to modified saturated polynisder resin compositions. More specifically, the present invention relates to a modified saturated polyester resin composition that has improved heat resistance and does not impair transparency.

In general, polyester resins, particularly polyethylene terephthalate (hereinafter abbreviated as PET), are widely used as fibers, films, and various molded products due to their excellent physical and chemical properties. In particular, molded containers made of P El' have recently attracted attention because of their excellent properties such as mechanical strength, gas barrier properties, and transparency.

However, although various molded products using PET have the above characteristics, their heat resistance is still insufficient.
Improvements have been desired for a long time.

Methods to improve heat resistance include keeping hot stones in the mold at high temperatures during conventional molding, and using compounds that promote crystallization of saturated polyesters (e.g. benzoic acid, terephthalic acid, stearic acid, phosphonic acid, or bosphinic acid). A method of adding an alkali metal salt, etc.) is known. However, the former method involves contact with the mold 11! It is difficult to say that it is an economical method of manufacturing molded products because it requires a long time.
Further, in the latter case, there were disadvantages such as whitening of the preform, making stretch blow molding difficult, and a 1q composition having an opaque appearance.

This invention was made in view of such conventional problems. The present inventors have conducted extensive studies on saturated polyester resins with good heat resistance that do not have the above-mentioned drawbacks, and have developed a composition in which a saturated polyester resin to be molded contains a compound having at least two or more methacryloyl groups. The present invention was achieved by discovering the fact that saturated polyester resin molded products and materials for molded products with improved heat resistance and good transparency can be efficiently obtained by irradiating ionizing radiation.

Even if a compound containing at least two methacryloyl groups used in this invention is actually simply added to a saturated polyester resin and a heat curing treatment is attempted, the desired composition cannot be obtained. In addition, the technology of modifying PlusDeck with ionizing radiation is also known for polyethylene, etc., but depending on the type of plastic, molecular chain collapse and disproportionation occur, resulting in uniformly good crosslinking. Therefore, it cannot necessarily be said to be an effective means of reforming. Furthermore, even if a saturated polyester resin (molded article) is simply irradiated with ionizing radiation, good crosslinking will not occur and the desired molded article will not be obtained.

In other words, the most distinctive feature of this defense lies in the combination of ionizing radiation irradiation and a specific compound, which produces good crosslinking in the saturated polyester chains and creates a saturated polyester resin (molded body). The key point is that it has made it possible to modify

Thus, according to the present invention, a modified saturated poly-1 stellate resin composition is provided, which is obtained by mixing a saturated polyester resin with a compound having at least two methacryloyl groups, and irradiating this composition with ionizing radiation. .

The above-mentioned composition includes any form, for example, it may be a molded product, that is, a form molded into a desired shape, such as granules, pellets, sheets, etc., or an amorphous plastic 4J I+ It may be in the form of

In this invention, the saturated polyester resin refers to a thermoplastic saturated polyester resin that does not have unsaturated bonds involved in curing in the molecule, which is obtained by a polycondensation reaction between a polybasic acid and a polyhydric alcohol. cover Examples of these shells include PET, P[3T (polybubulene derephthalate) ~), poly 1,4-cyclohexylene dimethylene derephthalate, polyethylene terephthalate 1~/isophthale 1~ copolymer, poly 1.
4-cyclo to 4-silenedimethylene terephthalate-1/
Examples include Isoftasy 1 to co-assembly, and various additives may be contained therein.

Examples of compounds containing at least two methacrylate[1-yl groups used in the present invention include poly-1 ethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, neA-bentyl glycol dimethacrylate, 1.6
-hexanethiol dimethacrylate 1, ■ dilene glycol dimethacrylate, di-nib-lene gelicold dimethacrylate, ]-lyethylene glycol dimethacrylate 1~, dib 1 copylene gelicol dimethacrylate, butylene glycol dimethacrylate-1 , 1,3-butanediΔ-dimethacrylate-1 to trimedylolpropane trimethacrylate, ]-limethylolethane trimethacrylate, and detramedylolmethanetetramethacrylate-1.Kasa. In particular, compounds containing a large number of methacryloyl groups are preferred. Among these, 1 to rimedylolpropane trimethacrylate, trimedylolconitane trimethacrylate and tetramethylolmethantei
~ la methacrylate is preferred.

A small amount of a compound having at least two or more methacryloyl groups is mixed into the saturated polyester resin. The mixing at this time may normally be carried out by melt mixing, and it is convenient to mix using an extruder and form pellets or granules, but it is also possible to form the desired shape by mixing using a mold.

At this time, the mixing ratio of the compound having at least two methacryloyl groups to the saturated polyester resin is 0.
The amount is 1 to 20 parts by weight, preferably 1 to 10 parts by weight. If it is less than 0.1 part by weight, the effect of addition is insufficient, and if it is more than 200 parts by weight, the molding of the composition becomes poor, which is not preferable.

The composition thus obtained is irradiated with an electric alpha 1 beam after it is directly or optionally thermoformed.Usually, the composition described above requires subsequent molding. It is preferable to mold the final product (for example, a container) using a mold or the like before irradiating it.

Examples of the electric N1 radiation radiation used in this invention include β rays, γ rays, accelerated electron beams, and radiation generated by reflection and scattering of these rays, and radiation sources include nuclear reactors, radioactive isotopes, etc. , electron beam accelerator, etc.

Irradiation is performed at room temperature, and the irradiation atmosphere is air or an inert gas (nitrogen or argon gas). The line m required for modification varies depending on the shape and size of the irradiated object, but
Absorption kneading is usually carried out to give an amount of 1 to 60 Mr'ad, preferably 1C) to 60 Mr'ad. 60M
If it exceeds rad, polymer chains such as 117i may occur, which is not preferable.

The thus obtained modified saturated polyester resin composition of the present invention has polymer chains crosslinked via a methacryloyl compound by the cooperative action of ionizing radiation and a methacryloyl compound, and has a high gel fraction. It has improved heat resistance. Furthermore, since it does not contain any compound that promotes crystallization, the transparency is not impaired in any way, and the appearance is comparable to that of conventional molded products such as PUT.

As shown from the above description, the modified saturated polynisder resin composition of the present invention can be obtained by adding a specific compound and for a short period of time (
By irradiating with ionizing radiation (usually within 10 minutes), it can be efficiently removed without the need for heat treatment or sensitizers such as radical generators, and in particular, heat resistance is required. It is useful for various purposes such as food containers and their base materials.

Examples of the present invention will be described in detail below, but the present invention is not limited thereto.

Example 1 Polyethylene derephthalate h with a number average molecular weight of 116,000
5 mm parts of each of the various additives shown in Table 1 were weighed to 100 molds and mixed in a tumbler. Next, it was put into an extruder, the solution H1lf1 was combined, and after quenching, it was formed into pellets.

The obtained pellets were irradiated with an electron beam using a 750 KV, 40 mA transformer type electron beam accelerator.

Table 1 shows the gel fraction measurement results for irradiated Belene 1 and comparative examples.
Shown below.

(Continued on next page in margin F) Table 1 Additives Irradiation fiMrad Gel fraction %A, l-limedilol-0 0 1[Ipan-56,3 trimethacrylate 10 10.4 20 15.5 30 23. 5 40 34.3 60 37.6 B, ethylene-〇〇glycol-53,8 dimethacrylate-1-107,5 2012,7 3018,6 4025,3 6034,1 Table 1 (continued) Additive M for irradiation rad Glue fraction % None OO (Comparative example) 10 0 20 0 40 0 60 0 Gel fraction is the difference with respect to the trial resin weight when the irradiated pellet is heated and dissolved in 0-chlorophenol at about 120°C. This is the ratio of dissolved residue. As is clear from Table 1, the electron beam irradiated composition does not completely dissolve M1!0-[10phenol, which is known as the best solvent for polyester. First, chemical resistance is determined by the fact that 30% or more of the material remains as insoluble matter.

Next, the irradiated pellet (30 Mrad of Example A in Table 1)
Figure 1 shows Char 1~ obtained by subjecting the char (obtained by irradiation) to thermal analysis (DSC) along with a comparative example.
Solid lines indicate comparative examples; dashed lines indicate no examples).

All comparative samples showed polynisder glass transition,
Peaks associated with crystallization and melting appear, but when the gel fraction is 2
As shown by the broken line in FIG. 1, the samples of Examples with T of 0% or more disappear from the peaks associated with glass transition and crystallization, indicating improved heat resistance.

Regarding transparency, there was no change in appearance between the unirradiated transparent molded product and the irradiated product.

[Brief explanation of drawings]

Ru.

Claims (5)

[Claims] (1) A modified saturated polynisder resin composition obtained by mixing a saturated polyester resin with a compound containing at least two methacryloyl groups, and irradiating this composition with ionizing radiation. (2) The modified saturated polyester according to claim 1, wherein the amount of the compound containing at least two methacryloyl groups is 0.1 to 20 parts by weight per 100 parts by weight of the saturated polyester resin. Resin composition. (3) The modified saturated polyester resin composition according to claim 2, wherein the compound having at least two methacryloyl groups is blended in an amount of 1 to 10 parts by weight per 100 parts by weight of the saturated polyester resin. . (4) The modified saturated polyester resin composition according to any one of claims 1 to 3, wherein the modified saturated polyester resin composition is subjected to an electric PII radiation treatment such that the absorption tfAm is 1 to 60 megarads. (5) The covering compound containing at least two methacryloyl groups is poly-1-ethylene glycol dimethacrylate-1-,
To poly 1 ethylene glycol dimethacrylate 1, 1,3-
Butylene glycol dimethacrylate, ne A pendyl glycol dimethacrylate-1-, 1,6-hekylene di A
-dimethacrylate-1~, ■dilene glycol dimethacrylate 1-, diethylene glycol dimethacrylate i~
, triethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, butylene glycol dimethacrylate-1., 1,3-butanediol dimethacrylate-1-, trimethylolpropane! 5. The modified saturated polyester resin composition according to any one of claims 1 to 4, which is trimethacrylate, trimethylolethane trimethacrylate-1 to tetramedylomethane 1 to methacrylate-h.