JPS6032814A - 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 acryloyl 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 acryloyl groups (preferably a compound having 3 acryloyl groups, e.g. trimethylolpropane triacrylate, pentaerythritol triacrylate, etc.), 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 polyester resin compositions. More specifically, the present invention relates to a modified saturated polyester resin composition that has improved heat resistance and maintains 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 PET have recently attracted attention because they have excellent properties such as mechanical strength, gas barrier properties, and transparency.

However, although various molded products using PET have the above-mentioned characteristics, their heat resistance is still insufficient, and improvement thereof has been desired for a long time.

Methods to improve heat resistance include maintaining the mold temperature at high humidity during conventional molding, and using compounds that promote the crystallization of saturated polyesters (e.g. benzoic acid, prephthalic acid, stearic acid, phosphonic acid, A method of adding an alkali metal salt of phosphinic acid, etc.) is known. However, the former method requires a long contact time with the mold, making it difficult to say that it is an industrially effective method for manufacturing molded products, and the latter method causes whitening of the preform, making stretch blow molding difficult. There were drawbacks such as the molding being difficult to form and the resulting molded product having an opaque appearance.

This invention was made in view of such conventional problems. The inventors of the present invention have conducted extensive studies on saturated polyester resins with good heat resistance that do not have the above-mentioned drawbacks. This 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 objects with ionizing radiation.

Even if a compound having at least two acryloyl groups used in the present 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, C may cause molecular chain collapse, disproportionation, etc., resulting in uniformly good crosslinking. However, it cannot be said to be an effective means of reforming. Furthermore, even if a saturated polyester resin (molded article) is simply irradiated with ionizing 11 radiation, good crosslinking will not occur and the desired molded article will not be obtained.

In other words, the most distinctive feature of this invention is the combination of irradiation with electron-111 radiation and a specific compound, thereby creating good crosslinks in the saturated polyester chains and making it possible to modify the saturated polyester resin. It's about getting used to it.

Thus, according to the present invention, a modified saturated polyester resin composition is provided in which a saturated polyester resin is mixed with a compound having at least two acryloyl groups, and this composition is irradiated with ionizing radiation.

The above-mentioned composition may be in any form, for example, it may be in the form of a molded product or a desired shape, such as granules, pellets, sheets, etc., or an irregularly shaped plastic snack. It may be in the form of a material.

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. do. Specific examples of these include PET, PBI- (poly-1-dylene terephthalate), poly-1,4-cyclohexylene dimethylene terephthalate, poly-1-dylene terephthalate-1/isophthalate copolymer, and poly-1.4-cyclohexyl. Examples include dimethylene terephthalate/isophthalate copolymer, and various additives may be included.

Examples of compounds having at least two acryloyl groups used in this invention include ethylene glycol diacrylate 1-, ethylene glycol diacrylate,
Polyethylene glycol diacrylate! ~, 1,3-butylene glycol diacrylate, 1,5-pentanediol diacrylate-1, neopentyl glycol diacrylate-1~, 1゜6-hex'' non-diA-diacrylate-1~, polypropylene glycol diacrylate, hydroxypivalic acid neopendyl glycol ester diacrylate-1~, pentaerythrityl diacrylate-1-1~
1., 1.3-butanediol diacrylate 1-. 1.
4-butanediol diacrylate 1~, triethylene glycol diacrylate, tripropylene glycol diacrylate 1~, bisdiethylene glycol phthalate 1~
~Diacrylate]~, trimedylolpropane triacrylate, pentaerythri 1-~Luna 1 to la acrylate 1, pentaerythri]--rutriacrylate, 1-
Reacryl formal, methyltri(acryloyl[1xy]xy)silane, triacryloyloxyethyl incyanurate, dipentaerythritol 1-1 pentaacrylate 1~, dipentaerythritol hexaacrylate
1-, detramedilolmethane detraacrylate-1~,
Proboxylated trimedylolpropane triacrylate 1, propo4 dilated dosphenol A
Diacrylate, ■Toxylated bisphenol Δ
diacryle-1-1], lith(acryloyloxyedyl)phosphate-1, and the like. Among these, those containing three or more acryloyl groups are preferred, and those containing three acryloyl groups are usually preferred.

A small amount of a compound having at least two or more acryloyl groups is mixed into the saturated polyester resin. Mixing at the time of mixing is usually done by melt a mixing, and it is convenient to mix using an extruder and form penta 1 or granulate, but it is also possible to form the desired shape by mixing using a mold. . In this case, the amount of the compound having at least two acryloyl groups mixed with the saturated polyester resin is 0.1 parts per 1100 filt parts of the saturated polynisder resin.
~20 parts by weight, preferably 1 to 10 parts by weight. If it is less than 0.1 parts by weight, the effect of the addition will be insufficient, and if it is more than 20 parts by weight, the moldability of the resulting composition will deteriorate, which is undesirable.

The composition prepared in this manner is irradiated with an electric rigid radiation 11.1 after being subjected to thermoforming as it is or optionally. Usually, it is preferable that the above-mentioned composition is molded into the shape of a final product (for example, a container) using a mold, etc., which does not require any subsequent molding processing, and then irradiated.

The ionizing radiation used in this invention includes β rays, γ rays,
Examples include accelerated electron beams and radiation obtained by reflection and scattering thereof, and examples of radiation sources include nuclear reactors, radioisotopes, electron beam accelerators, and the like.

The irradiation is performed at room temperature, and the irradiation atmosphere 1111 is performed in air or an inert gas (nitrogen or argon gas). The Ijlffi required for modification varies depending on the shape and size of the object to be irradiated, but is usually carried out so that the absorption line m is 1 to 60 Mrad, preferably 10 to 60 Mrad.

If it exceeds 60 M rad, it is not preferable because it may cause fragmentation of polymer chains.

The thus obtained modified saturated polyester resin composition of the present invention has polymer chains crosslinked via the acryloyl compound due to the cooperative action of lightning η1 radiation and the acryloyl compound, and has a high gel fraction. It has improved heat resistance. Furthermore, since it does not contain compounds that promote crystallization as in conventional products, transparency is not impaired in any way, and the appearance is comparable to that of ordinary molded products such as PET.

As shown from the above explanation, the modified saturated polyester resin composition of the present invention can be produced by adding a specific compound and for a short period of time (
By irradiating with ionizing radiation (usually within 10 minutes), it can be obtained efficiently without the need for heat treatment or sensitizers such as radical generators, and especially heat resistance is required. It is useful in a variety of applications, such as food containers.

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

Example 1 To 100 parts by weight of polyethylene derephthalate having a number average molecular weight of 116,000, 5 ffiffi parts of each of the various additives shown in Table 1 were weighed and mixed in a tumbler. Next, it was put into an extruder, melted and mixed, and after quenching, it was turned 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 of irradiated pellet 1- and comparative examples.
Shown below.

(Margin below, continued on next page) Table 1 Additives Irradiation ffiMracl Gel fraction %Δ, trimedylol-00 Propane-54,1 Triacrylate-1-108,3 2012,7 3021,2 4030,8 6035,2 B , De1 Hera Ethylene-00 Glycol-57,5 Diacrylate h 10 13.4 20 23.5 30 32.1 40 38.6 60 43.2 Table 1 (continued) Additive Irradiation dose M rad Glue fraction % None 00 (Comparative example) 10 0 20 0 40 0 60 0 The gel fraction is the sample resin ff1ff when the irradiation plate 1 is heated and dissolved in 0-chlorine 1 alcohol at about 120°C
It is the ratio of undissolved residue to J. As is clear from Table 1, 0-
For chlorophenol, the composition subjected to electron beam irradiation does not completely dissolve, and has kJ drug properties in which significantly more than 40% remains as insoluble matter.

Next, the irradiated pellets (obtained by 30 Mrad irradiation in Example A of Table 1) were subjected to thermal analysis (DSC), and the obtained titers are shown in Figure 1 together with comparative examples. indicates a comparative example, and a dashed line indicates an example).

In the comparison example υ sample, all polyester 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, in the sample of Example 2, the peaks associated with glass transition and crystallization disappear, indicating an improvement in heat resistance.

Regarding transparency, there was no change in appearance between the unirradiated and irradiated samples.

[Brief explanation of the drawing]

FIG. 1 is a differential thermal analysis curve illustrating the thermal properties of the modified saturated polyester resin composition of the present invention.

Claims (5)

[Claims] (1) A modified saturated polyester resin composition obtained by mixing a saturated polyester resin with a compound containing at least two acryloyl groups, and irradiating this composition with ionizing radiation. (2) The modification according to claim 1, wherein the compound having at least two acryloyl groups is blended in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the saturated polyester resin. quality saturated polyester resin composition. (3) The modified saturated polyester resin composition according to claim 2, wherein the amount of the compound covering at least two acryloyl groups is 1 to 10 parts by weight per 100 parts by weight of the saturated polyester resin. thing. (4) Ionizing radiation irradiation treatment has an absorption Min of 1 to 6
Claim 1: 0 Megarad
The modified saturated polynisder resin composition according to any one of items 1 to 3. (5) The compound containing at least 211+a or more acryloyl groups is ethylene glycol diacrylate, tetraethylene glycol diacrylate-1~, polyethylene glycol diacrylate-1~, 1,3-butylene glycol diacrylate, 1. 5-bentanediol diacrylate, neopendel glycol diacrylate, 1
, 6-hekylindiol diacrylate, polypropylene glycol diacrylate, hydroxypivalic acid neopentyl glycol ester diacrylate, pentaerythritol diacrylate, 1,3-butanediol diacrylate, 1.4-butanediA-diacrylate-1 -, triethylene glycol diacrylate, triplyne glycol diacrylate, bisdiethylene glycol phthalate diacrylate, trimethy O-
Propane triacrylate, pentaerythritolte 1-la acrylate, pentaerythritol triacrylate, triacryl formal, methyltri(acryloyloxyethoxy)silane, triacryloyloxyethyl isocyanurate, dipentaerythritol pentaacrylate, dipentaerythritol Hexaacrylate, Te1~ramedilolmethante1~laacryle-1~, propoxylated 1-rimedylol-but-1-copane triacrylate-1-, propoxylated bisphenol A diacrylate, ethoxylated bisphenol A diacrylate, or The modified saturated polyester resin composition according to any one of claims 1 to 4, which is 1-lith(acryloylogyethyl)bosphate.