JP2527505B2 - Method for producing unsaturated polyester - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD 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, a sheet molding compound, Sheet Molding Compound (S)
MC), and 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-
It is a kind of prepolymer of about 2500,
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SUMMARY OF THE INVENTION The present inventors have proposed, as a previously untried, at least unpublished method, the deglycolization found in the production of unsaturated polyesters and in the production of polyethylene terephthalate.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). In a method for producing an unsaturated polyester by esterifying with an alcohol and then performing a deglycolization reaction, 0.01 to 3 parts by weight of an organic antimony compound is esterified or deestered with respect to 100 parts by weight of the produced unsaturated polyester. The present invention provides a method for producing an unsaturated polyester, which is characterized in that it is added at the stage of glycol reaction.

The present invention will be described in more detail below.
The reason for using the organic antimony compound in the present invention is
It is to suppress the increase of the weight average molecular weight as much as possible while increasing the number average molecular weight of the resulting unsaturated polyester, and to safely perform the synthesis reaction without gelling. The present invention, the above-mentioned organic antimony compound, while effectively acting to increase the number average molecular weight, it has been found that the tendency to increase the weight average molecular weight is less than when using a general organometallic compound Is based. Antimony compounds are very commonly used as catalysts in the synthesis of polyethylene terephthalate, but not in the production of unsaturated polyesters. The reason is that the conventional production of low molecular weight unsaturated polyester does not require a deglycolization reaction, and at least an example of synthesizing an unsaturated polyester by carrying out a deglycolization reaction at the risk of gelation has been published. You can't see it at the stage. Therefore, there is no example of using an organic antimony compound as a catalyst for the deglycolization reaction. The reason why the organic antimony compound is used as the catalyst for the deglycolization reaction according to the present invention is the first.
First, it is to improve the hue of the produced high molecular weight, and secondly, to maintain the balance between the number average molecular weight and the weight average molecular weight, and to allow the safe execution of the reaction. That is, during the synthesis of the unsaturated polyester, the number average molecular weight is increased, the increase in the weight average molecular weight is suppressed as much as possible, and the reaction can be safely performed without gelation. Further, 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 continues to increase with the reaction time and finally reaches the gel. Leading to This point is a point that is fundamentally different from thermoplastic polyester (saturated polyester).
It is also the reason why the conditions for producing unsaturated polyester cannot be known. Various kinds of organic antimony compounds can be used in the present invention, and examples thereof include trinormal butoxy antimony, triisopropyl antimony, and tributyl antimony. these
Organic antimony compounds are commercially available and preferred because they are easy to synthesize. The amount of the above-mentioned organic antimony 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 unsaturated polyester produced.

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 an α, β-unsaturated polybasic acid represented by fumaric acid or maleic anhydride or its acid anhydride is essential, and any saturated or unsaturated polybasic acid (or its anhydride) should be used in combination. In general, it is common practice to provide resin with various physical properties. In the synthesis of the unsaturated polyester according to the present invention, a general esterification is followed by a deglycolization reaction. However, the addition of the organic antimony compound may be added from the beginning of the esterification, or at the initiation time of the deglycolization reaction. Good. 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. Agent, thermoplastic polymer,
Of course, a curing agent or the like can be used in combination.

[0006]

EXAMPLES In order to facilitate understanding of the present invention, examples will be shown below.

Example 1 A 1 l separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube was charged with ethylene glycol 75.
g, dipropylene glycol 150 g, isophthalic acid 1
66 g and 1.6 g of trinormal butoxyantimony (manufactured by Nippon Kagaku Sangyo Co., Ltd.) were charged until the acid value reached 19.1.
After proceeding the esterification at 190 to 200 ° C., 102 g of adipic acid and 35 g of fumaric acid were added, and the acid value was adjusted to 7.8.
(At this time, the number average molecular weight is about 2500), the temperature is 200 to 290 ° C., and finally under a reduced pressure of 0.5 mmHg, 8
The glycol removal reaction was carried out for a period of time. As a result of measuring the refractive index, the distillate was estimated to be approximately 72% ethylene glycol and 28% dipropylene glycol. The unsaturated polyester (C) thus obtained had a number average molecular weight of 9,300, was almost colorless, and was a solid with a softness. Subsequently, 500 g of the unsaturated polyester (C) was dissolved in 500 g of styrene containing 0.1 g of hydroquinone. The polyester resin (D) thus obtained has a Hazen color number of 10
The viscosity was 0 and the viscosity was 3.9 poise. To 100 g of polyester resin (D), 1.5 g of methyl ethyl ketone peroxide, 0.5 g of cobalt naphthenate and 0.2 g of acetylcyclopentanone were added, and the mixture was cast into a 2 mm thick mold and gelled at 80 ° C. It was cured for 2 hours at 120 ° C. for 2 hours. The cured resin has a tensile strength of 3.1 kg / m
The m ² and the elongation rate were 135 to 140 (%).

[0008]

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 that has not been obtained previously, and it can be applied to a wide range of fields such as home appliances, automobiles and housing equipment. We provide high-performance polyester resins.

[Brief description of drawings]

FIG. 1 is a diagram showing a molecular weight distribution of an unsaturated polyester obtained by the present invention before and after a deglycolization reaction.

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. In a method for producing an unsaturated polyester by esterifying with an alcohol and then performing a deglycolization reaction, 0.01 to 3 parts by weight of an organic antimony compound is esterified or deestered with respect to 100 parts by weight of the produced unsaturated polyester. A method for producing an unsaturated polyester, which comprises adding at the stage of glycol reaction.