JP2002060474A - Method for producing unsaturated polyester resin - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To decompose waste PET bottles and the like, replace conventional organotin catalysts with organic titanium catalysts represented by alkoxytitanium compounds and zinc organic compounds represented by zinc acetate. By using an acid-based catalyst, the decomposition can be performed efficiently. SOLUTION: In a state where polyethylene terephthalate is heated and melted to a melting point (about 260 ° C.) or higher or before heat melting, an organic compound of titanium and / or an organic acid salt of zinc is added to 100 parts by mass of polyethylene terephthalate. 0.01 parts by mass or more and 3 parts by mass or less, further decompose by adding a polyhydric alcohol, and then add an unsaturated polybasic acid or an acid anhydride thereof and, if necessary, a saturated polybasic acid or an acid thereof. An anhydride is added and polycondensation is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an unsaturated polyester resin.

[0002]

2. Description of the Related Art In recent years, the technology for recycling polyethylene terephthalate (hereinafter sometimes referred to as "PET") materials has been advanced, and in particular, recovered polyethylene terephthalate (hereinafter referred to as "R-PET") such as waste PET bottles has been developed. The flakes or pellets of the final product obtained by the material recycling process have been used for recycled fibers, various containers and the like.

Although many techniques have been studied for chemical recycling, most of them are techniques for decomposing R-PET into raw materials for polyester synthesis and reusing it as a PET material. On the other hand, R-PE
There was a technique for recomposing T into glycol and resynthesizing it into an unsaturated polyester resin. However, in this case, generally, R-PET was gradually dissolved in a glycol solution heated to around 200 ° C. It was necessary to add it and decompose the glycol over a long period of time. However, this method
As described above, in addition to spending a long time in decomposition, the amount of R-PET to be added is at most 30 to the amount of glycol.
%, And when it was attempted to increase the amount of R-PET, it was solidified and precipitated, and it became impossible to stir normally, so that practical application was difficult.

That is, in the conventional method, when R-PET is glycol-decomposed to obtain a predetermined degree of decomposition (degree of depolymerization), if R-PET is added to glycol at once, it cannot be contained in a container. Therefore, it was necessary to add this in portions. In addition, since it is impossible to raise the temperature above the boiling point of the glycol, the depolymerization of R-PET took an extremely long time.

On the other hand, R-PE is contained in the above glycol solution.
Instead of the method of sequentially adding T, for example,
In JP-A-7770 and JP-A-11-60707, R-PET is melted at about 280 ° C., and an organotin-based catalyst such as dibutyltin oxide is added thereto in advance with glycol. Addition methods have been proposed. According to this method, glycol can be added almost at once, and R-PET can be added in an amount of 0.1 mol to 10 mol per 1 mol of glycol.
For this reason, it is a very excellent method for decomposing glycol when performing chemical recycling of R-PET.

[0006]

The present inventors have found that, besides the above-mentioned tin-based catalysts, organic titanium-based catalysts and zinc-based organic acid-based catalysts have similar effects, although the efficiency of glycol decomposition is slightly reduced. I found that there was.

That is, the present invention uses an organic titanium-based catalyst represented by an alkoxytitanium compound or a zinc organic acid-based catalyst represented by zinc acetate instead of a conventional organic tin-based catalyst. The present invention proposes a method for efficiently decomposing R-PET such as waste PET bottles.

[0008]

According to the present invention, an organic compound of titanium and / or an organic acid salt of zinc are prepared in a state in which polyethylene terephthalate is heated and melted to a melting point (about 260 ° C.) or higher or before heat melting. , With respect to 100 parts by mass of polyethylene terephthalate, added in an amount of 0.01 to 3 parts by mass, further decomposed by adding a polyhydric alcohol, and then adding an unsaturated polybasic acid or an acid anhydride thereof. The polycondensation is carried out by adding a saturated polybasic acid or an acid anhydride thereof accordingly.

In the present invention, the polyhydric alcohol is used in an amount of from 0.1 mol to 10 mol per 1 mol of the condensed unit of polyethylene terephthalate.

That is, the present invention provides a method for melting R-PET,
By adding a desired amount of an organic compound of titanium, typically alkoxides, and / or an organic acid salt of zinc, typically zinc acetate, the disadvantages of the conventional method are eliminated, and the decomposition reaction is completed in a short time. Is found to be terminated.

That is, even if R-PET is simply melted and glycol is added thereto, a large amount of glycol may be added in a short time (depending on the scale of the reaction system, generally 30 minutes or If it is added below, the unresolved R-PET precipitates and solidifies, so that there is a limit to shortening the reaction time. However, according to the method of the present invention, even when the ratio of R-PET, which was considered impossible with the conventional method, is high (0.1 mol of glycol or more per mol of R-PET), the unsaturated polyester resin Can be manufactured. In addition, the reaction time can be remarkably reduced, and the cost merit is extremely large.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As PET (polyethylene terephthalate) used in the present invention, R-
PET is typical, but not limited thereto.

In the present invention, an organic compound of titanium and / or an organic acid salt of zinc are added to the PET. As the organic compound of titanium, alkoxides of titanium are particularly preferably used. Titanium chelate compounds, such as acetylacetonates, can also be used in combination, but there is a problem in coloring. Examples of titanium alkoxides include tetraethoxytitanate, tetraisopropoxytitanate and tetrabutoxytitanate, which exhibit sufficient performance to achieve the object of the present invention.

It is also possible to use an organic acid salt of zinc in combination with the organic compound of titanium or alone. As the organic acid salt of zinc, zinc acetate is typical.

The ratio of the organic compound of titanium or the organic acid salt of zinc is 0.01 to 100 parts by mass of PET.
It is necessary that the amount is not less than 3 parts by mass and not more than 3 parts by mass. 0.
If the amount is less than 01 parts by mass, the added amount is too small, and a substantial effect due to the addition cannot be expected. Conversely, even if it exceeds 3 parts by mass, further improvement in performance can no longer be expected. For this reason, a more desirable use ratio is 0.1 part by mass or more and 1 part by mass or less.

These cracking catalysts may be added after PET is heated and melted to a melting point or higher, or PET may be added in a non-molten state and then melted and homogenized.

The polyhydric alcohol, ie, glycol, used in the present invention is not particularly limited, but when it is dissolved in a monomer such as styrene after completion of esterification, it increases oil solubility. In addition, glycols having a high alkyl group, for example, propylene glycol, 1,2 butanediol, 1,3 butanediol,
Neopentyl glycol and the like are advantageous. On the other hand, a molding material in which the generated unsaturated polyester resin is crystalline and a waxy solid is required even if it contains a monomer,
For applications such as laminates, it is desirable to use a combination of glycols such as ethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol, which do not hinder crystallinity.

The proportion of the glycol used is preferably from 0.1 mol to 10 mol, and more preferably from 0.2 mol to 8 mol, per mol of the condensed unit of polyethylene terephthalate. . When the amount is less than 0.1 mol, the degree of polymerization of polyethylene terephthalate does not decrease, so that the solubility in styrene monomer or the like is extremely poor, and also as a resin molded product, the crosslink density is low and the physical strength is low. On the other hand, if it exceeds 10 moles, the material may not have sufficient performance as an unsaturated polyester resin.

Examples of unsaturated polybasic acids or acid anhydrides thereof include maleic anhydride, maleic acid, fumaric acid,
Itaconic acid is a typical example. The usage rate is PE
For a total of 10 moles of T and glycol used,
It is preferable that the amount is 1 mol or more and 9 mol or less.

If the amount is less than 1 mol, the properties of the resulting unsaturated polyester resin after curing are inferior, and the practicability is poor. If it is 9 mol or more, the use ratio of PET is reduced, and the significance of the present invention is lost.

Examples of the saturated polybasic acid or its acid anhydride include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, adipic acid, sebacic acid and the like. The saturated polybasic acid or its acid anhydride may be used as needed, and may not be used if unnecessary.

The unsaturated polyester resin using PET obtained according to the present invention can be impregnated into glass fiber and cured to form an FRP, and can be added to fillers and other necessary additives to form an SMC (sheet). Molding materials).
Its applications are wide and diverse.

[0023]

EXAMPLES Next, examples will be shown below to facilitate understanding of the present invention. (Example 1) Stirrer, reflux condenser, dropping funnel,
Flake (R-PE) of waste PET bottles was crushed in a 2-liter separable flask equipped with a gas inlet tube and a thermometer.
345 g of T) was collected and placed in a reaction flask. Next, tetrabutoxy titanate, which is a depolymerization catalyst, was added in an amount of 0.9.
g (0.2% by mass based on R-PET flake + glycol), raise the internal temperature to 280 ° C. or higher,
The ET flake was melted.

Next, 108 g of 1,2-butanediol was added to 1
Charged within 0 minutes. No precipitation of the contents occurred here. Furthermore, while maintaining the internal temperature at 210 to 220 ° C., stirring was continued for 5 hours to perform glycol decomposition.

After that, the decomposition state was examined with a glass rod every hour, and it was confirmed that the acetone could be melted and the glycol decomposition had sufficiently proceeded one hour later.
R-PET was measured by weight average molecular weight measurement by GPC analysis.
It was confirmed that the decomposition had progressed to several units of the polycondensation unit. GPC = 786.

Next, the reflux condenser was replaced with a fractionation condenser, the temperature was lowered to 210 ° C., and 110 g of maleic anhydride was melted and dropped. After the esterification was performed for 30 minutes, polycondensation was finally performed under a reduced pressure of 20 Torr for 5 hours to obtain an acid value of 13. Then, the esterification was terminated, and 0.1 g of hydroquinone was added.
A styrene monomer was added and dissolved under an air stream so that the content became 40%, whereby an unsaturated polyester resin (A) could be produced. Thereby, the Hazen color number 35
A slightly turbid unsaturated polyester resin (A) having a viscosity of 0 and a viscosity of 11.4 poise was obtained.

To 100 parts by weight of the resin (A), 1.2 parts by weight of methyl ethyl ketone peroxide, 0.5 part by weight of cobalt naphthenate (6% Co), 0.1 part by weight of dimethylaniline
Parts by weight were added. The system gelled in 11 minutes at room temperature and rapidly exothermicly hardened.

The Barcol hardness of the cured resin after standing overnight was 38. (Example 2) In the same manner as in Example 1, other depolymerization catalysts were examined.

That is, 0.3% by mass of zinc acetate was added in place of the tetrabutoxytitanate of Example 1, and the temperature was raised to 280 ° C. in the same manner as in Example 1 except for the above.
And when apparent dissolution began, 108 g of 1,
2-butanediol was gradually added. No deposition of the contents occurred here.

In this state, glycol decomposition was performed for 5.5 hours. Further, 110 g of maleic anhydride was added, and 5.5
A time esterification reaction was performed. The esterification was terminated at an acid value of 34, and a styrene monomer to which 0.1 g of hydroquinone was added was added so as to be 40% by mass, whereby an unsaturated polyester resin (B) could be produced.

The unsaturated polyester resin (B) had a Hazen color number of 300 and a viscosity of 13.9 poise. The Percoll hardness of the resin cured under the same conditions as in Example 1 was 39. (Example 3) Into the same apparatus as in Example 1, 334 g of flakes (R-PET) obtained by pulverizing a waste PET bottle was charged.
After dissolving at 265 to 270 ° C, 1 g of tetraisopropoxytitanium and 1.6 g of zinc acetate were added and uniformly dissolved. Thereafter, 266 g of propylene glycol was added in 5 minutes. A slight agar-like precipitate was observed in the contents, but there was no problem with stirring. Then, after glycol decomposition was carried out at 200 ° C. for 5.5 hours, the reflux condenser was changed to a fractionation condenser, and 196 g of maleic anhydride and 148 g of phthalic anhydride were added. And 2
Polycondensation was carried out at 00 to 205 ° C, and after 5 hours, the mixture was kept under reduced pressure of 10 Torr for 30 minutes to obtain an acid value of 29.4. Thereafter, the temperature was lowered to 150 ° C., 0.1 g of hydroquinone was added, and then the styrene monomer was added so as to be 40% by mass. As a result, Hazen color number 2 with almost no turbidity
As a result, an unsaturated polyester resin (C) having a viscosity of 50 and a viscosity of 13.1 poise was obtained. The Barcol hardness of the resin cured in the same manner as in Example 1 was 42.

[0032]

As described above, according to the present invention, an organic compound of titanium and / or an organic acid salt of zinc are mixed with polyethylene terephthalate in a state in which polyethylene terephthalate is heated and melted to a melting point or higher or before heat melting. 0.01 parts by mass or more and 3 parts by mass or less with respect to parts by mass, further decomposed by adding a polyhydric alcohol,
Then, while adding an unsaturated polybasic acid or its acid anhydride, and adding a saturated polybasic acid or its acid anhydride as needed, and performing polycondensation, it is considered impossible to carry out the conventional method. Even when the ratio of R-PET is high, (R
-0.1 mol of glycol or more per mol of PET),
It becomes possible to produce unsaturated polyester resins.
In addition, the reaction time can be significantly reduced, and the cost merit is extremely large.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nobu Yoshimura 4-115-304 Hashimoto, Sagamihara-shi, Kanagawa F-term (reference) 4J029 AA07 AB04 AE01 BA03 BA05 BA07 BA08 BA09 BA10 BD06A BE07 CA02 CA06 CB04A CB05A CB06A GA12 GA13 GA14 GA17 HD01 JE162 JF181 JF321 KB02 KB03 KB05 KG00

Claims (2)

[Claims] 1. An organic compound of titanium and / or an organic acid salt of zinc in a state in which polyethylene terephthalate is heated and melted to a melting point or higher or before heat melting, in an amount of 0.01 parts by weight based on 100 parts by weight of polyethylene terephthalate Not less than 3 parts by mass and further decomposed by adding a polyhydric alcohol, and then adding an unsaturated polybasic acid or an acid anhydride thereof and, if necessary, adding a saturated polybasic acid or an acid anhydride thereof. And performing polycondensation of the unsaturated polyester resin. 2. The process for producing an unsaturated polyester resin according to claim 1, wherein the proportion of the polyhydric alcohol is from 0.1 mol to 10 mol per 1 mol of the condensed unit of polyethylene terephthalate.