JPH0768439B2 - UV curable resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention has improved the phenomenon that a molded product of a polyethylene terephthalate resin that has not been subjected to cooling and stretching treatment becomes brittle when heated at a relatively low temperature, for example, 150 ° C. for several hours. It relates to an ultraviolet curable resin composition.

[Conventional technology]

Polyethylene terephthalate resin (hereinafter referred to as PET) is mainly used in the form of fibers, films, etc. in large amounts for electrical insulation and the textile industry. It is well known that the crystal structure of these is tough and flexible because the crystal structure is oriented and regulated by the cooling stretching process and the heat setting process, and the crystal structure does not easily change at a temperature of about 200 ° C. and the flexibility is maintained. On the street.

[Problems to be solved by the invention]

However, when this PET is integrally molded with a constituent material such as a metal, the subsequent cooling and stretching treatment is not possible, and as a result, PET is severely embrittled by heat and cannot be put to practical use.

In view of such points, the present inventors integrally molded this useful PET, which has been used for many years, with other constituent materials such as metal, and does not become embrittled by heat even without the subsequent cooling and stretching treatment. We succeeded in obtaining a PET resin composition.

Even if the PET molded product is not subjected to cooling and stretching treatment, it is highly flexible by adjusting its cooling rate, etc., but even at 150 ° C, which is relatively low compared to the processing temperature, the crystal structure changes in several hours, It becomes brittle. Therefore, we considered mixing various functional resins to prevent changes in the crystal structure and conducting cross-linking with various cross-linking agents.However, the cross-linking partially or completely progressed depending on the PET processing temperature, and during the processing The gelled product could not be obtained stably due to gelation.

However, the present inventors have found that only a composition containing a certain functional resin and a Lewis acid free photopolymerization initiator capable of initiating the polymerization of this functional resin is thermally stable, and is incorporated into PET. It was discovered that due to the plasticizing effect of the above-mentioned functional resin, the extrusion processing temperature is lowered, it is hardly decomposed at that temperature, and it can be freely molded and processed, and also retains the UV polymerization function after the fact.

Thus, by mixing the epoxy resin with the composition of the polyester resin that helps depopulation in PET, and by incorporating the Lewis acid free photopolymerization initiator, it is possible to mold freely, only after the ultraviolet treatment. It has succeeded in obtaining an excellent epoch-making resin composition which does not cause thermal embrittlement.

[Means for solving problems]

The UV-curable resin composition of the present invention comprises 25 to 70% by weight of the polyethylene terephthalate resin in a resin containing a polyethylene terephthalate resin as a main component, from a polyester resin and a polyester oligomer which soften at a relatively low temperature. Polyethylene terephthalate-based resin substituted with one or more selected from the group consisting of and one or more cationically polymerizable compounds containing an epoxy resin having two or more oxirane rings in one minute as a main component A mixture of 30% by weight or less with respect to the polyethylene terephthalate-based resin, an aromatic onium salt, which is a photopolymerization initiator of the cationically polymerizable compound that liberates a Lewis acid catalyst by ultraviolet irradiation, to the cationically polymerizable compound. On the other hand, 0.1 to 10% by weight is included.

The PET resin used in the present invention is preferably a commercially available polyethylene terephthalate resin such as a grade for films or fibers, or a grade for bottles whose degree of polymerization is increased by a solid-state polymerization method, but if the softening point is 170 ° C. or higher, isophthalic acid is used. It is also possible to use those containing the components or polybutylene terephthalate resin.

In order to improve the processability of PET at low temperatures, one of polyester-based resins represented by ELITER (manufactured by Unitika Ltd., product name) or polyester-based oligomers represented by Desmorphen (manufactured by Bayer, product name) One obtained by substituting 70% by weight or less of PET with one kind or a mixture of two or more kinds is used.

The cation-polymerizable compound used in the present invention is one or more of cation-polymerizable compounds whose main component is an epoxy resin having two or more oxirane rings in one molecule. The epoxy resin is a bisphenol A type epoxy resin. ,
A novolac type epoxy resin or the like is preferable.

Examples of the bisphenol A type epoxy resin include Epicoat 828, Epicoat 834, Epicoat 836,
Epicoat 1001 (above, product name of Shell Chemical Co., Ltd.), DE
R331, DER332, DER661, (all manufactured by Dow Chemical Co., trade name), Araldite 260, Araldite 280, Araldite 6071 (all manufactured by Ciba Geigy, trade name), etc., can be used alone or in combination. .

Examples of the novolac type epoxy resin include Epicoat 152, Epicoat 154 (all manufactured by Shell Chemical Co., trade name), Araldite EPN1138, Araldite EPN.
1139, Araldite ECN1235, Araldite ECN1273, Araldite ECN1280, Araldite ECN1299 (above, Ciba Geigy, trade name), DEN431, DEN438 (above, Dow Chemical Co., trade name), etc., and these may be used alone or in combination. Used.

A monofunctional epoxy diluent may be used for the cationically polymerizable compound as long as the curing characteristics are not deteriorated. Examples of such monofunctional epoxy diluents include phenyl glycidyl ether and t-butyl glycidyl ether.

It is also possible to use a cationically polymerizable vinyl compound mixed with the epoxy resin. Examples of such cationically polymerizable vinyl compound include styrene, allylbenzene, triallyl isocyanate, triallyl cyanate, vinyl ether and N-vinyl. Carbazole,
Examples thereof include N-vinylpyrrolidone.

The photopolymerization initiator used in the present invention to release the Lewis acid catalyst which initiates the polymerization of the cationically polymerizable compound upon irradiation with ultraviolet rays, is a photosensitive aromatic onium salt of a Group VIa element or a Group Va element. And so on.

Examples of the photosensitive aromatic onium salt of the Group VI a element or the Group V a element include the general formula (I): ▲ [(R ₁ ) _i (R ₂ ) _j (R ₃ ) _k Y] _l ⁺ _l ▼ 〔MQm〕 ^- _(mn)
[I] [In the formula, R ₁ is a monovalent aromatic organic group, R ₂ is a monovalent aliphatic organic group selected from the group consisting of an alkyl group, a cycloalkyl group and a substituted alkyl group, and R ₃ is an aliphatic group. A heterocyclic group selected from an organic group and an aromatic organic group or a polyvalent organic group forming a condensed ring structure, Y is selected from the group VIa elements of S, Se and Te or N, P, As, Sb and Bi. Group V a element, M
Is a metal or semimetal, Q is a halogen atom, i is an integer of 0 to 4, j is an integer of 0 to 2, k is an integer of 0 to 2, and (i + j + k) is equal to the valence of Y. , Y is 3 when the group VIa element, and 4 when Y is the group Va element, l = (m−n) holds, and n is 2 to 7
Is an integer equal to the valence of M, and m is an integer of 8 or less, which is greater than n.
Examples of onium salts of group elements include As the onium salt of the Group V a element,
For example And so on. Note that diazonium salts and halonium salts are known as photopolymerization initiators that liberate the Lewis acid catalyst, but the thermal stability of the catalyst is poor, and it is difficult to use in the present invention according to the experiments of the present inventors. Is.

Further, in the present invention, from the viewpoint of the thermal stability of the catalyst, the VIa
Onium salts of group elements are preferred.

The amount of the Lewis acid free photopolymerization initiator added to the cationically polymerizable compound is 0.
It is 1 to 10% by weight, preferably 1 to 5% by weight. If it is less than 0.1% by weight, the crosslinking reaction rate by ultraviolet rays becomes slow,
The treatment time tends to be too long, and if it exceeds 10% by weight, the cost of the catalyst is high and the price of the resin composition increases.

The resin composition of the present invention can be used as a constituent material integrated with a metal or the like by a molding process such as injection, extrusion or pressing, that is, a corrosion-resistant metal material, an electronic circuit substrate, an insulated wire or the like. In addition, irradiation with a light source such as a low-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, a carbon arc lamp or electron beam irradiation is used for the ultraviolet crosslinking treatment after the molding process.

Example of Invention

Next, the resin composition of the present invention will be described in detail based on examples and comparative examples, but the present invention is not limited to the following examples.

Example 1 Bellpet EFG-6 pellets 5 manufactured by Kanegafuchi Chemical Industry Co., Ltd.
Freeze-grinding 0 parts by weight, mixing 30 parts by weight of Desmorphen F-951 (low molecular weight polyester resin) and 20 parts by weight of Epicoat 828 (bisphenol A type epoxy resin), kneading with a kneader at 280 ° C. for 10 minutes, then Cooled and pelletized. 20 parts by weight of this mixture was freeze-ground, and 1.2 parts by weight of a 50% by weight propylene carbonate solution of triphenylsulfonium hexafluoroantimonate (photopolymerization initiator) in the obtained porous powder was sufficiently mixed at room temperature,
A so-called catalyst masterbatch was created. Next, 20 parts by weight of this masterbatch and the remaining 80 parts by weight of the pelletized mixture are mixed and charged into a hopper of an extruder of L / D = 20 held at a parel 220 ° C. and a head 240 ° C. With a pressure of 0.25 mm and a width of 50 mm, the thickness of the composition is 50
It was extrusion-coated with μ to obtain a copper strip integrally molded on one side.

Bending characteristics of this molded product before and after UV treatment with a diameter of 3 mm and 180 °, a steel ball with a diameter of 1.6 mm was placed on the coated surface, a load of 1 kg was applied on it, and AC 100 V was applied between the steel ball and the copper strip. Table 1 shows the softening points measured by loading and heating at a rate of about 2 ° C./min in a constant temperature bath.

Example 2 40 parts by weight of Belpet EFG-6 pellets were freeze-milled,
25 parts by weight of Elitere UE-3700 (polyester resin for hot melt manufactured by Unitika Ltd.), Desmofen F
20 parts by weight of -951 (low molecular weight polyester resin) and 15 parts by weight of Epicoat 828 were mixed and kneaded in a kneader at 280 ° C. for 10 minutes, then cooled and pelletized.

20 parts by weight of this mixture was freeze-milled, and UVI 6970 (50% by weight propylene carbonate solution of a sulfonium salt photopolymerization initiator manufactured by GE Co., Ltd.) 1.0 part by weight was sufficiently mixed with the obtained porous powder at room temperature, A catalyst masterbatch was prepared.

Next, 20 parts by weight of this master batch and 80 parts by weight of the above mixture were mixed, and L / D was maintained at a barrel 215 ° C and a head 235 ° C.
It was put into a hopper of an extruder of 20 and a T-shaped die was used to extrusion-coat a copper strip having a thickness of 0.25 mm and a width of 50 mm with a composition thickness of 50 μ to obtain a copper strip integrally molded on one side.

The bending characteristics and the softening point of the coating before and after the UV treatment of this molded article are measured according to Example 1, and the results are shown in Table 1.

Example 3 A catalyst masterbatch mixed pellet obtained in the same manner as in Example 2 was held in a barrel 215 ° C. and a head 235 ° C. L / D = 2
Charged into the hopper of the extruder of 6 and 1.0 by the crosshead
It was extruded on a copper wire having a diameter of mm with a thickness of 40μ to obtain an insulated electric wire.
Table 1 shows the results of measuring the winding flexibility and softening point of this insulated wire before and after UV treatment according to JIS C3003.

Example 4 65 parts by weight of pellets of Bellpet EFG-6 were freeze-ground,
Desmorphen F-951 (Low molecular weight polyester resin) 2
2 parts by weight, 10 parts by weight of Epicoat 828 and 3 parts by weight of Epicoat 152 (novolak type epoxy resin) were mixed, kneaded in a kneader at 280 ° C. for 10 minutes, then cooled and pelletized.

20 parts by weight of this mixture was freeze-ground, and 1.0 part by weight of UVI 6970 (photopolymerization initiator) was sufficiently mixed with the obtained porous powder at room temperature to prepare a catalyst masterbatch.

Then, 20 parts by weight of this masterbatch and the remaining 80 parts by weight of the above pelletized mixture were mixed, and barrel 220 ° C., head 2
Put into the hopper of the extruder with L / D = 26 kept at 40 ℃,
An insulated electric wire was obtained by extruding with a crosshead onto a 1.0 mm diameter copper wire with a thickness of 40 μm. Table 1 shows the results of measuring the winding flexibility and softening point of this insulated wire before and after UV treatment according to JIS C3003.

Comparative Example 1 PET pellets were kept at a barrel temperature of 250 ° C and a head of 290 ° C.
It was put into the hopper of an extruder with / D = 20, and it was extrusion-coated with a thickness of 50μ on a copper strip having a thickness of 0.25 mm and a width of 50 mm by a T-type die to obtain a copper strip integrally molded on one side. The bending characteristics and softening point obtained by the same method as in Example 1 are shown in Table 1.

Comparative Example 2 PET pellets were charged into the same extruder as in Example 3 in which the barrel temperature was 250 ° C. and the head temperature was 290 ° C., and the thickness was 4 on a 1.0 mm copper wire.
It was extruded at 0μ to obtain an insulated electric wire.

Table 1 shows the measurement results of winding flexibility and softening point in accordance with JIS C3003.

Comparative Example 3 Bellpet EFG-6 pellets (85 parts by weight) were freeze-milled,
Mix 15 parts by weight of Epikote 828 and kneader at 280 ℃
Kneading for 10 minutes, then cooling and pelletizing.

20 parts by weight of this mixture was freeze-ground, and 1.0 parts by weight of UVI6970 (photopolymerization initiator) was sufficiently mixed with the obtained porous powder at room temperature to prepare a catalyst masterbatch.

20 parts by weight of this masterbatch and 80
Part by weight was mixed and put into the hopper of an extruder with L / D = 26, and it was extruded onto a 1.0 mm diameter copper wire by a crosshead to make an insulated wire.
At ℃, the temperature was insufficient and the temperature did not discharge.
Melt discharge started at 0 ° C and head 260 ° C, but after 5 minutes, thermal decomposition of the photopolymerization initiator was observed at that temperature, and crosslinked gelation due to the released Lewis acid occurred in the barrel. However, the insulated wire was not obtained.

As is clear from the experimental results shown in Table 1, Comparative Examples 1-2
The PET-only molded product shown in (2) has a severe thermal embrittlement and cannot be put to practical use. Further, even when a sulfonium salt-based photopolymerization initiator is used, if low-molecular weight polyesters for sufficiently lowering the processing temperature of the composition are not blended, as shown in Comparative Example 3, gelation occurs during molding and molding I can't get anything. On the other hand, in Examples 1 to 4 of the present invention, gelling did not occur during the molding process, and the obtained molded products were obtained by blending the low molecular weight polyester resin, oligomer and epoxy resin that had not been irradiated with ultraviolet rays. It works as a plasticizer and has a low softening point, and the phenomenon of thermal embrittlement is also recognized. However, by irradiating it with ultraviolet light, the softening point is also improved,
It can be seen that embrittlement due to heat deterioration is almost completely improved.

It should be noted that the one obtained by subjecting the molded product using the resin composition according to the present invention to the ultraviolet irradiation treatment is also excellent in mechanical strength, electrical insulation, solvent resistance and the like, and is a very useful resin composition. confirmed.

The present invention is not limited to a composite molded product with a metal, and is also useful when the resin composition of the present invention is used alone regardless of a metal material. Therefore, it is considered that the resin composition alone is used for a sheet, a film, a bolt, etc. In this case, the ultraviolet irradiation treatment after the cooling and stretching treatment is effective.

〔The invention's effect〕

According to the present invention, the epoxy resin is mixed with the composition in which the polyester resin that aids plasticization in PET is mixed, and the Lewis acid free photopolymerization initiator is mixed, so that it can be freely molded, and ultraviolet rays after the An excellent epoch-making resin composition which does not cause thermal embrittlement can be obtained only by the treatment.

Claims (2)

[Claims] 1. A polyethylene terephthalate resin containing a polyethylene terephthalate resin as a main component,
Polyethylene terephthalate resin in which 25 to 70% by weight is substituted with one or more selected from the group consisting of polyester resins and polyester oligomers which soften at a relatively low temperature, and an oxirane ring in one molecule Two
One or a mixture of two or more cationically polymerizable compounds whose main component is an epoxy resin having not less than 30% by weight with respect to the polyethylene terephthalate resin, and further the cation which liberates a Lewis acid catalyst by ultraviolet irradiation. Aromatic onium salt, which is a photopolymerization initiator of a polymerizable compound, is contained in an amount of 0.1 to 10% by weight based on the cationically polymerizable compound.
An ultraviolet-curable resin composition comprising: 2. The photopolymerization initiator is a group VIa element or a group Va.
The ultraviolet-curable resin composition according to claim 1, which is one kind or a mixture of two or more kinds selected from the group consisting of a photosensitive aromatic onium salt of a group element.