KR100496040B1 - Manufacturing method of toughened epoxy resin using polyester waste chips - Google Patents

Abstract

The present invention relates to a method for producing toughened epoxy resin using polyester waste chips, which have been disposed of as a source of environmental pollution, as a modifier of an epoxy resin, and the modified epoxy resin produced has excellent heat resistance, which is inherent in epoxy resins. It is excellent in toughness while maintaining mechanical properties, and thus can be effectively applied to applications requiring both heat resistance and mechanical properties and impact resistance.

Description

Manufacturing method of toughened epoxy resin using polyester waste chips

The present invention relates to the use of polyester waste chips, and more particularly, to a method for producing toughened epoxy resins using polyester waste chips.

Recently, due to the rapid development of the industrial and economic structure, the use of plastics is rapidly increasing in all fields such as automobiles, aircrafts and general household appliances. In particular, in the case of engineering plastics, due to their excellent mechanical, chemical and electrical properties, they are widely used as industrial, medical and household materials. However, these plastics do not decompose in nature after disposal, causing serious social problems such as environmental pollution. Therefore, research on biodegradation and recycling of waste plastics has attracted attention.

PET chip chips are generated during the production process of polyester fiber chips such as polyethylene terephthalate (PET). These chips are discarded as they are not reusable during the fiber process.

These waste chips are produced by friction between chips and wall during storage and transportation of polymerized polyester chips. If these chips are passed to spinning process without separating and removing these chips, spin pack due to melt defect Increasing the pressure causes the process to become unstable, resulting in problems such as single yarns in the stretching process and uneven dyeing in the salt and processing processes.

On the other hand, epoxy resin is a representative thermosetting resin that reacts with a curing agent to become an insoluble and insoluble thermosetting resin, and is used as an adhesive, a coating agent, an electrical insulation agent, and a matrix of a composite material because of its excellent mechanical, electrical, and chemical properties. However, since epoxy resins are inherently brittle, their application has been limited to applications requiring impact resistance.

In an attempt to compensate for the brittleness of the epoxy resin, modification by liquid rubber such as carboxyl terminal butadiene acrylic rubber and amine terminal butadiene acrylic rubber, modification by engineering plastics such as polyethylene terephthalate and polyphenylene oxide, and polyetherimide Modification by super engineering plastics, such as polyether sulfone and polysulfone, is performed.

The former modification method shows a very good performance in terms of impact resistance, but has the disadvantage of lowering heat resistance and mechanical properties, which are inherent to epoxy resins. Therefore, in recent years, modifications by engineering or super engineering plastics that maintain the intrinsic properties of epoxy and develop impact resistance have been actively studied.

Here, in the case of the modification by polyethylene terephthalate, PET is a crystalline polymer, so it must be mixed by melt blending with an epoxy resin, but in order to melt the PET, this should be performed at a high temperature of 270 ° C. or higher. The curing reaction is so fast that gelation may occur during melt mixing. In the present invention, however, the epoxy resin is preheated at a temperature of about 180 ° C., and the PET powder chips are dispersed and mixed therein, so that the aforementioned problems are not caused.

In the study of the present inventors for utilizing the polyester waste chip as described above, the polyester waste chip obtained during the polyester fiber chip production process has a high melting point in a cyclic oligomer (mainly trimer) state represented by the following formula (1). It does not melt at the melting temperature of ordinary PET chips, which causes fatal damage to polyester fibers, but blending with epoxy resin makes it a filler while dispersing it in the form of powder in the epoxy matrix by utilizing the mechanical properties of PET. When the impact from the outside, the impact energy is absorbed to improve the brittle properties of the epoxy resin. On the other hand, the toughening of the epoxy resin by PET shows excellent effects in terms of flexural strength and fracture energy in the case of the minute chips having a small particle size of PET with PET dispersed in the epoxy matrix.

[Formula 1]

Therefore, an object of the present invention is to produce toughened epoxy resin using polyester waste chips as a modifier.

According to the present invention for achieving the above object, the process of adding 30 to 5% by weight of polyester waste chips to 70 to 95% by weight of the preheated epoxy resin, and adding the epoxy curing agent to the resulting mixture and curing under heating Provided is a method for producing a toughened epoxy resin using a polyester waste powder chip comprising a step of making the powder.

Hereinafter, the present invention will be described in more detail.

In the manufacturing method of this invention, it is preferable to mix | blend an epoxy resin with 70-95 weight% and polyester waste chip | tip with 30-5 weight% in the mixing of a polyester powder chip and an epoxy resin. If the blending ratio of the polyester waste chips exceeds 30% by weight, the toughness can be improved, but the heat resistance and mechanical properties, which are inherent to the epoxy resin, are lowered, and the blending ratio of the polyester waste chips is less than 5% by weight. The toughness improvement effect is insignificant. In addition, the polyester waste chip and the epoxy resin is required to be mixed with the curing agent after mixing as uniformly as possible. For this purpose, it is preferable to preheat the epoxy resin before mixing with the polyester chip.

The uniformly mixed polyester waste chip / epoxy resin mixture is mixed with a curing agent, and mixing with the curing agent is performed by lowering the temperature of the polyester waste chip chip / epoxy resin mixture slightly to prevent curing of the epoxy resin during mixing. desirable. It is preferable that the polyester waste chip / epoxy resin / curing agent mixture obtained by mixing the curing agent removes air bubbles contained in the mixture before heating to produce a uniform cured product after heating. 180-220 degreeC is suitable for the temperature at the time of heat hardening.

The modified epoxy resin prepared according to the present invention as described above, while maintaining the excellent heat resistance and mechanical properties that are inherent to the epoxy resin, the toughness is improved, so that the application range is also required for applications requiring both heat resistance and mechanical properties as well as impact resistance. It can be widened.

Features and other advantages of the present invention as described above will become more apparent from the description of the embodiments described below. Of course, the present invention is not limited to the following examples.

<Example 1>

After preheating 95 g of the bifunctional epoxy resin represented by the following Chemical Formula 2 to 180 ° C., 5 g of polyethylene terephthalate waste chips containing the cyclic trimer of Chemical Formula 1 as a main component was added and mixed well. The resultant mixture was cooled to 140 ° C., and 31 g of diphenyldiamine sulfone (DDS) was added thereto as a curing agent, and the bubbles formed during the mixing were removed by a vacuum oven. The degassed mixture was poured into a mold preheated to 180-220 ° C. and cured for 3 hours. The flexural strength and fracture energy of the obtained specimens were measured and shown in Table 1 below.

[Formula 2]

<Example 2>

The same procedure as in Example 1 was repeated except that the mixing weight ratio of epoxy resin / PET chip was 90/10.

<Example 3>

The same procedure as in Example 1 was repeated except that the mixing weight ratio of epoxy resin / PET chip was 80/20.

<Example 4>

The same procedure as in Example 1 was repeated except that the mixing weight ratio of epoxy resin / PET chip was 70/30.

<Comparative Example 1>

The specimen was prepared by curing under the same conditions as in Example 1 using only epoxy resin. The flexural strength and fracture energy of the obtained specimens were measured and shown in Table 1 below.

<Comparative Example 2>

Example 1 and the weight ratio and mixing method was repeated, except that PET pellets were used instead of PET waste chips.

TABLE 1

※ Epoxy resin / PET pallet (weight ratio)

As shown in Table 1, when the ratio of the epoxy resin / polyester powder chip is mixed in the range of 95 to 70/5 to 30 wt%, the bending strength is high and the breaking energy is also high.

As described above, the present invention makes it possible to utilize polyester waste chips that have been conventionally disposed to cause environmental pollution, and also have excellent toughness while maintaining excellent heat resistance and mechanical properties, which are inherent to epoxy resins. In addition, there is an effect of providing a high value-added modified epoxy resin that can be effectively applied to applications requiring impact resistance.

Claims (2)

Polyester waste comprising the steps of adding 30 to 5% by weight of polyester waste chips to 70 to 95% by weight of the preheated epoxy resin, and adding epoxy curing agent to the resulting mixture and curing under heating. Method for producing toughened epoxy resin using chip chips. The method for producing toughened epoxy resin using polyester waste chips according to claim 1, wherein the curing temperature is 180 to 220 캜.