JP5022578B2 - Modified styrene-fumaric acid copolymer, unsaturated polyester resin composition, unsaturated polyester resin molded article, and method of using waste plastic - Google Patents

Description

The present invention relates to a modified styrene- fumaric acid copolymer that reuses a plastic containing an unsaturated polyester resin that is used for a household product represented by a bathroom member or an aircraft member, and an unsaturated polyester resin composition using the same. Product, unsaturated polyester resin molded product, and waste plastics.

  Plastic is representative of bathroom materials because it has the advantages of light weight, high strength, resistance to rust and corrosion, free coloring, excellent electrical insulation, easy molding, and mass production. It is widely used as a member for household goods, automobiles, airplanes and the like. As the amount of plastic used increases, the amount of plastic discarded tends to increase. In order to reduce the burden on the environment, technologies for recycling waste plastic have been actively developed.

For example, a method of treating waste plastic in a large amount by decomposing and plasticizing waste plastic at high speed with subcritical water has been disclosed (see Patent Document 1). According to this method, a low molecular weight oily component generated by decomposing waste plastic is recovered as a liquid fuel, and the recovered liquid fuel is reused as a fuel for a thermal power generation boiler. However, even if the recovered liquid fuel is reused as the fuel for the thermal power generation boiler, the CO ₂ emission is not suppressed, and the environmental load cannot be reduced.

Therefore, a technique for hydrolyzing a plastic containing a thermosetting resin using subcritical water having a strong hydrolytic ability has been proposed. That is, a raw material monomer of a thermosetting resin produced by hydrolyzing a thermosetting resin with subcritical water is recovered, and the raw material monomer is reused as a resin raw material (see Patent Document 2). Using this method, an unsaturated polyester resin composed of an unsaturated polyester part formed from a polyhydric alcohol (glycol) and an unsaturated fatty acid (fumaric acid) and a cross-linking part that crosslinks the unsaturated polyester part is obtained. When processed, raw material monomers can be obtained.
Japanese Patent Laid-Open No. 10-67991 Japanese Patent Laid-Open No. 10-24274

  However, even if the above-mentioned thermosetting resin is hydrolyzed and recovered, if the recovered decomposition product is reused as it is as a raw material for the resin, the resulting resin shrinks, becomes brittle, and may deteriorate. It was. For this reason, it is desired to modify the resin recovered by hydrolysis and reuse it as a resin raw material.

The present invention has been made to solve the above problems, i.e., modified styrene of the present invention - fumaric acid copolymer, styrene obtained by decomposing the subcritical water unsaturated polyester resin - fumaric acid The gist is obtained by dehydrating a copolymer with alcohol or phenol.

Unsaturated polyester resin composition of the present invention, styrene - fumaric acid copolymer alcohols or phenols by dehydration reaction with resultant modified styrene - fumaric acid copolymer, a styrene, an unsaturated polyester, a radical The gist is to include an initiator.

  The unsaturated polyester resin molded product of the present invention is obtained by molding the unsaturated polyester resin composition.

The method of using the waste plastic of the present invention is a modified styrene- fumaric acid copolymer obtained by subjecting a styrene- fumaric acid copolymer obtained by hydrolyzing an unsaturated polyester resin with subcritical water to a dehydration reaction of alcohol or phenols. The gist is to form a resin composition by molding a resin composition in which the resulting modified styrene- fumaric acid copolymer , styrene, unsaturated polyester, and radical initiator are mixed.

According to the modified styrene- fumaric acid copolymer of the present invention, the waste plastic can be reused as a low shrinkage agent, so that resources can be effectively utilized.

  According to the unsaturated polyester resin composition of the present invention, a low shrinkage rate can be maintained.

  According to the unsaturated polyester resin molded product of the present invention, the dimensional accuracy can be increased.

  According to the method for using waste plastic of the present invention, a resin molded product having low shrinkage can be obtained by reusing waste plastic.

Hereinafter, a modified styrene- fumaric acid copolymer according to an embodiment of the present invention, an unsaturated polyester resin composition using the same, an unsaturated polyester resin molded product, and a method of using waste plastic will be described.

The modified styrene- fumaric acid copolymer according to the embodiment of the present invention can be obtained as follows.

  First, a plastic containing an unsaturated polyester resin composed of an unsaturated polyester portion and a cross-linked portion thereof is hydrolyzed using subcritical water (below 280 ° C., 7 MPa or less) that is below the temperature at which the unsaturated polyester resin is thermally decomposed. To do. Then, an aqueous glycol solution is obtained.

During glycol solution, a polyhydric alcohol which is a raw material monomer of the unsaturated polyester resin (glycol) and organic acids (fumaric acid), compounds of the bridge and an organic acid unsaturated polyester resin (scan styrene and fumaric acid Copolymer). The styrene-fumaric acid copolymer has the structure shown in Chemical Formula 1, has both a hydrophilic group and a hydrophobic group, and has properties such as a surfactant.

As a specific method of the hydrolysis, for example, a plastic containing an unsaturated polyester resin, pure water, and potassium hydroxide are charged into a reaction tube, and the inside of the reaction tube is replaced and sealed with a rare gas. After immersing the reaction tube in a thermostatic chamber (about 230 ° C), it is hydrolyzed with subcritical water for 4 hours. After filtering and separating the hydrolyzed contents, an acid (for example, hydrochloric acid, sulfuric acid, etc.) is further added to recover a copolymer of styrene and fumaric acid .

Further, the recovered styrene- fumaric acid copolymer is subjected to a dehydration reaction with alcohol or phenol to obtain a modified styrene- fumaric acid copolymer . Examples of the alcohol used herein include monohydric alcohols and polyhydric alcohols. For example, monohydric alcohols are preferably methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, etc., and polyhydric alcohols are ethylene. Glycols such as glycol, diethylene glycol, propylene glycol and dipropylene glycol are preferred. Further, as the phenols, for example, phenol, salicylic acid, naphthol, catechol, resilcinol, hydroquinone and the like are preferable.

The obtained modified styrene- fumaric acid copolymer is mixed in the resin and reused as a low shrinkage agent.

  Hereinafter, more specific description will be given using examples. Prior to describing the examples, a reference example will be described.

Reference Example Using propylene glycol as the glycol and maleic anhydride as the organic acid, both were subjected to polycondensation in equimolar amounts to obtain an unsaturated polyester resin having a weight average molecular weight of 4000 to 5000. This unsaturated polyester resin varnish (without solvent) is blended with styrene, methyl ethyl ketone peroxide as radical initiator and calcium carbonate as inorganic filler in a weight ratio of 1: 0.02: 2 to unsaturated polyester resin 1, and further Polystyrene was added as a low shrinkage material so as to be 10% by weight with respect to the total amount of the composition, and cured to obtain a cured product.

Example 1
First, 3 g of the cured product of the above reference example, 15 g of pure water, and 0.84 g of potassium hydroxide were charged into a reaction tube, and the inside of the reaction tube was replaced with argon gas. This reaction tube was immersed in a thermostatic bath at 230 ° C., and water was hydrolyzed for 4 hours in a subcritical state. Thereafter, the contents inside the reaction tube were filtered and separated, and hydrochloric acid was further added to recover a styrene- fumaric acid copolymer .

The above operation was repeated, and 50 g of the obtained styrene- fumaric acid copolymer was dissolved in 100 g of methanol and stirred for 15 minutes. Thereafter, the mixture was reacted for 18 hours under reflux conditions, and then 100 g of distilled water was added to precipitate the modified resin. This was a low shrinkage agent.

  Next, the varnish of the unsaturated polyester resin used in the reference example was mixed in an approximately equivalent amount with styrene, and a varnish / styrene / calcium carbonate blending system obtained by adding calcium carbonate was used. The modified resin was blended so as to be 10 parts by weight and then cured to obtain a cured product.

Comparative Example First, 3 g of the cured product of the above reference example, 15 g of pure water, and 0.84 g of potassium hydroxide were charged into a reaction tube, and the inside of the reaction tube was replaced with argon gas. This reaction tube was immersed in a constant temperature bath at 230 ° C., and the decomposition reaction was carried out for 4 hours with water in a subcritical state. Thereafter, the contents inside the reaction tube were filtered and separated, and hydrochloric acid was further added to recover a styrene- fumaric acid copolymer .

By repeating the above operation, the resulting styrene- fumaric acid copolymer was used as a low shrinkage agent.

Next, the varnish of the unsaturated polyester resin used in the reference example was mixed in an approximately equivalent amount with styrene, and a varnish / styrene / calcium carbonate blending system obtained by adding calcium carbonate was used. After blending so that the styrene- fumaric acid copolymer would be 10 parts by weight, it was cured to obtain a cured product.

  For each cured product obtained from the above Examples, Comparative Examples, and Reference Examples, the following measurement methods were used to measure the reaction rate, shrinkage rate, flexural modulus, bending strength, and Izod impact value. Physical properties were evaluated.

  The reaction rate was calculated from the amount of unreacted recovered by hot water reflux extraction.

  The shrinkage was calculated from the dimensional change after the compounded resin was poured into a 100 mm square mold and cured.

  The bending strength and flexural modulus were in accordance with JIS-K7017. Specifically, the strength associated with the variation of the indenter at the center of the test piece was measured, the elastic modulus at which the linear relationship between the variation and the strength was established was determined, and the bending strength was determined from the strength at the yield point. The dimensions of the test piece used here were a thickness of 2 mm, a width of 12 mm, a length of 80 mm, a fulcrum distance of 50 mm, and a test speed of 2 mm / min.

  The Izod impact test conformed to JIS-K7062. Specifically, after fixing one side of the test piece, the impact property was evaluated from the energy required for breaking by hitting with a hammer. The dimensions of the test piece used here were 2 mm thick, 12 mm wide, and 80 mm long.

The obtained results are shown in Table 1.

From the results shown in Table 1, in the comparative example using a styrene- fumaric acid copolymer that does not undergo a dehydration reaction with alcohol or phenols as a low shrinkage agent, a number of lumps are found on the surface of the cured product when the appearance is observed. Furthermore, the shrinkage rate was as high as 4%, and it was found that the properties of the obtained resin deteriorated because it shrinks when the resin is cured. On the other hand, on the surface of the cured product of the example, it was confirmed that a cured product having no lumps, a shrinkage rate, a bending elastic modulus, a bending strength, and an Izod impact value, which is comparable to the reference example, can be obtained. It was done.

As described above, according to the embodiment of the present invention, the styrene- fumaric acid copolymer obtained by hydrolyzing the waste plastic containing the unsaturated polyester resin with subcritical water is dehydrated with alcohol or phenols. It was found that waste plastic can be reused by using it as a low shrinkage agent after reaction, and the low shrinkage of the resulting resin can be maintained.

Claims (4)

A modified styrene- fumaric acid copolymer obtained by subjecting a styrene- fumaric acid copolymer obtained by hydrolyzing an unsaturated polyester resin with subcritical water to a dehydration reaction of alcohol or phenol. A modified styrene- fumaric acid copolymer obtained by dehydrating a styrene- fumaric acid copolymer with alcohol or phenol, styrene, an unsaturated polyester, and a radical initiator. Saturated polyester resin composition.   An unsaturated polyester resin molded product obtained by molding the unsaturated polyester resin composition according to claim 2. A styrene- fumaric acid copolymer obtained by hydrolyzing an unsaturated polyester resin with subcritical water is subjected to a dehydration reaction of alcohol or phenol to obtain a modified styrene- fumaric acid copolymer ,
Use of a waste plastic characterized by molding a resin composition obtained by mixing the resulting modified styrene- fumaric acid copolymer , styrene, unsaturated polyester, and radical initiator into a resin molded product Method.