JP2527506B2 - Method for producing unsaturated polyester - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high molecular weight unsaturated polyester having a molecular weight (number average molecular weight, the same applies hereinafter) of 5000 or more.

[0002]

2. Description of the Related Art Polyester resin (unsaturated polyester dissolved in a copolymerizable monomer is referred to as below) is used as a general-purpose FRP matrix resin in baths, septic tanks, vanities, etc. Residential equipment, fishing boats, leisure-related equipment and facilities, such as boats, yachts and other boats, as well as corrosion-resistant equipment, automobile parts, etc. It is also used for cast relations. For example, polyester resin is mixed with filler, glass fiber, curing agent, thickener and aged, and then sheet molding compound Sheet Molding Compaund (SM
C), it is used for housing equipment such as bathtubs, or outer panels of automobiles. However, as the applications are expanded, the physical properties of the resin are required to be higher, and it is necessary to further improve the boiling resistance, the strength, the elasticity, etc., for example. In order to meet such requirements, various methods for improving resins have been tried, but one of them is to increase the molecular weight. That is, by increasing the molecular weight of the unsaturated polyester that constitutes the polyester resin, the heat distortion temperature and the strength tend to increase. However, the current molecular weight of unsaturated polyester is 2000-2.
It is a so-called prepolymer of about 500, and as long as it depends on the esterification method, it is extremely difficult to further increase the molecular weight from the viewpoint of gelation risk. That is, in the deglycolization reaction following the esterification, the number average molecular weight does not change much from the stage where it reached a substantially constant value, while the weight average molecular weight continues to increase with the reaction time and finally gels. To reach.
This point is fundamentally different from the thermoplastic polyester (saturated polyester).

[0003]

SUMMARY OF THE INVENTION The present inventors have proposed, as a previously untried, at least unpublished method, the deglycolization found in the production of unsaturated polyesters and in the production of polyethylene terephthalate. A molecular weight of 5 is applied if the reaction is applied and the following conditions are met:
It was clarified that a high molecular weight polyester of 000 or more can be synthesized (Japanese Patent Application No. 1-292354). That is, (i) the acid value after esterification is 15 or less, preferably 10
In the following, (ii) a reduced pressure of 5 mmHg or less, preferably a reduced pressure of 1 mmHg or less, (iii) a tetraalkyl titanium compound is used as a catalyst for the deglycolization reaction. The present invention relates to a catalyst for a deglycolization reaction which replaces the above tetraalkyl titanium. That is, the present invention provides a polycarboxylic acid having or without modifying an α, β-unsaturated polybasic acid (or an acid anhydride thereof) with or without any saturated or unsaturated polybasic acid (or an acid anhydride thereof). Esterified with alcohol to an acid value of 10 or less ,
Then, a method for producing an unsaturated polyester by carrying out a deglycolization reaction, which comprises producing an unsaturated polyester 10
The esterification or alkoxy compound of 0.01 to 3 parts by weight based on 0 part by weight of an organic acid salt or alkoxy compound of at least one metal selected from the group consisting of zinc, cadmium, zirconium, cobalt, manganese, and tin is used. The present invention provides a method for producing an unsaturated polyester, which is characterized in that it is added at the stage of deglycolization reaction.

The present invention will be described in more detail below.
The reason for using the organic acid salt or alkoxy compound of the metal in the present invention is to increase the number average molecular weight of the unsaturated polyester to be produced, to suppress the increase of the weight average molecular weight as much as possible, without gelling the synthetic reaction, To do it safely. In the present invention, the above-mentioned metal organic acid salt or alkoxy compound is effective in increasing the number average molecular weight, but has less tendency to increase the weight average molecular weight as compared with the case of using a general organic metal compound. It is based on the point of finding. Some organic salts of heavy metals are useful as catalysts for deglycolization reaction, such as vanadium, iron, chromium, etc., and unsaturated polyesters obtained by using these are converted into styrene and the like. A polyester resin produced by dissolving it in a monomer is not always suitable as a catalyst because it has drawbacks such as poor storage stability, marked coloring, and impairing curability.
This is an example of what is different from the saturated polyester synthesis. As described above, one condition of the present invention is to apply a deglycolization reaction to obtain a high molecular weight of 5000 or more during the synthesis of unsaturated polyester.
Further, in the synthesis of unsaturated polyester, in the deglycolization reaction following the esterification, the number average molecular weight does not change significantly from the stage where it reached an almost constant value, while the weight average molecular weight is the reaction time. Along with that, gelation is finally reached. This is a point that is fundamentally different from the thermoplastic polyester (saturated polyester), and is the reason that the conditions for producing unsaturated polyester cannot be known from the knowledge of saturated polyester synthesis. Therefore, the catalyst for the deglycolization reaction must be of a type that suppresses an increase in the weight average molecular weight as much as possible, and the above-mentioned types can be said to be appropriate when considering the safety of the reaction. Examples of the organic acid salt of the metal that can be used in the present invention include:
Various types of organic acid salts can be used, and examples thereof include acetate, naphthenate, octylate, and oxalate. Specific examples thereof include zinc acetate, cadmium acetate, zirconium octylate, cobalt acetate, manganese acetate, stannous oxalate, dibutyltin oxide, triisopropyl zirconate, and tributyl zirconate. In addition to the above organic acid salts, alkoxy compounds of the above metals can also be used. The amount of the organic acid salt of the metal or the alkoxy compound used is 0.01 to 3 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the produced unsaturated polyester.

The raw material of the unsaturated polyester used in the present invention is not particularly limited, but has a molecular weight of 50.
In order to make it more than 00, 5 of the polyhydric alcohol used
It is preferable that the boiling point (760 mmHg) of 300 ° C. or less is 0 mol (%) or more. Use of α, β-unsaturated polybasic acid represented by fumaric acid and maleic anhydride or its acid anhydride is essential, and any saturated or unsaturated polybasic acid (or its acid anhydride) can be used in combination. Then, it is common practice to provide resin with various physical properties. In the synthesis of the unsaturated polyester according to the present invention, general esterification is followed by a deglycolization reaction, but the addition of the organic acid salt or alkoxy compound of the metal may be added from the beginning of the esterification. It may be the start time of the glycol reaction. Also, it is advantageous to add a polymerization inhibitor in order to prevent gelation during the reaction. The unsaturated polyester according to the present invention is dissolved in a copolymerizable monomer and used as a polyester resin for various purposes. At that time, if necessary, a reinforcing material, a filler, a colorant, a release agent, and a thickening agent. Of course, an agent, a thermoplastic polymer, a curing agent and the like can be used in combination.

Next, in order to help understanding of the present invention, examples will be shown below. (Example of esterification reaction) In a 30-liter stainless steel reaction vessel equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube, 8.8 kg of propylene glycol and 8.3 isophthalic acid.
After charging kg and esterifying in a nitrogen gas stream at 180 to 190 ° C to an acid value of 18.1, 5.8 kg of fumaric acid was added, the esterification temperature was set to 190 to 205 ° C, and the pressure was reduced to 10 to 12 mmHg at the end of the reaction. Was carried out for about 2 hours to give a final acid value of 6.5, 4 g of hydroquinone was added, and the mixture was allowed to flow into a metal vat and solidified. Softening point about 75 ° C, molecular weight about 2
300 light tan, solid unsaturated polyesters (I) were obtained.

Examples 1-10 Into a 1 liter separable flask equipped with a stirrer, a distilling condenser, a thermometer, and a gas introduction tube, 500 g of each of the unsaturated polyester (I) produced in the reaction example was charged, As shown in 1, an organic acid salt of the metal was added.

[0008]

[Table 1]

Each of these mixtures was melted to obtain 200
Depressurization was started at -205 ° C, the pressure was reduced from 5 mmHg to 0.5 mmHg over 6 hours, and the pressure was reduced to 0.7 to 0.5 mmHg for about 2 hours, followed by stirring to carry out a deglycol reaction. Table 2 summarizes the differences depending on the type of deglycolization catalyst. Compared to the case where no catalyst was added, all of them achieved a molecular weight of 5,000 or more, and it was judged that they have sufficient practicality from the hue and curability of the polyester resin in a 50% styrene solution.

[0010]

[Table 2]

[0011]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the deglycolization reaction can proceed without causing gelation, and it is possible to produce a high molecular weight unsaturated polyester which has not been obtained in the past. Provide high-performance polyester resin that can be applied to a wide range of fields such as automobiles and housing equipment.

Claims (1)

(57) [Claims] 1. An α, β-unsaturated polybasic acid (or its acid anhydride) is modified with or without any saturated or unsaturated polybasic acid (or its acid anhydride) to give a polyvalent polyhydric acid. esterified until an acid value of 10 or less in an alcohol, then under deglycol reaction, der process for producing an unsaturated polyester
Thus , 0.01 to 3 parts by weight of at least one metal organic acid salt or alkoxy selected from the group consisting of zinc, cadmium, zirconium, cobalt, manganese, and tin based on 100 parts by weight of the produced unsaturated polyester. A process for producing an unsaturated polyester, which comprises adding a compound at the stage of the esterification or deglycolization reaction.