JPH0689126B2 - Method for producing high molecular weight unsaturated polyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an unsaturated polyester having a number average molecular weight of 5,000 or more, which has hitherto been considered impossible to achieve.

[Conventional technology and problems]

In general, α, β unsaturated polybasic acid or its acid anhydride, typically maleic anhydride, fumaric acid, in combination with a saturated polybasic acid or unsaturated cyclic aliphatic polybasic acid or its acid anhydride, Unsaturated polyester obtained by esterification with polyhydric alcohols is dissolved in a copolymerizable monomer to make a polyester resin (hereinafter, in order to avoid confusion, the type with the monomer added is the polyester resin, and unsaturated with no monomer added. It is well known that alkyd is called unsaturated polyester to distinguish it.

This polyester resin is a fiber reinforced plastic (FR
P), paints, casting, etc. are used in a very wide range, and the production amount reaches to over 200,000 tons per year.

Although it is an industrially important polyester resin,
The number average molecular weight (hereinafter abbreviated as “molecular weight”) of the unsaturated polyester, which is a direct component thereof, is the same as that of the thermosetting resin and is at most 1000 to 2500, and no more than 3000 is found. It was no exaggeration to say.

The cause is nothing but the conventional direct esterification method of a polybasic acid or an acid anhydride thereof and a polyhydric alcohol cannot achieve the above-mentioned molecular weight due to gelation even if an attempt is made to obtain a molecular weight higher than the above.

In the synthesis of thermoplastic polyesters, there may be cases where a general deglycolization reaction was attempted, that is, a high temperature of 250 ° C or higher, a high reduced pressure of 1 mmHg or less, and the use of a metal compound catalyst. An attempt was made to synthesize a synthetic unsaturated polyester, but gelation was unavoidable even with the addition of a large amount of a polymerization inhibitor, and it failed.

It is clear that thermosetting unsaturated polyester cannot be synthesized under the general conditions for the synthesis of thermoplastic polyester, and there is an essential difference between the two. I can't find any cases where it was announced that the polyester synthesis was successful.

For example, in the case of a thermoplastic polyester resin, both the number average molecular weight and the weight average molecular weight decrease as shown in FIGS. 1 and 2 after the optimum time of the reaction conditions. In other words, it suggests that a decomposition reaction is occurring. On the other hand, in the case of unsaturated polyester, as shown in FIG. 3, the number average molecular weight becomes a constant value when it is slightly lower than the maximum value, whereas the weight average molecular weight is shown in FIG. As you can see, it is increasing. This shows that the unsaturated polyesters are cross-linked simultaneously with the decomposition, and it is clear that there is an essential difference in the reaction from these viewpoints.

[Means for Solving the Problems]

As a result of various studies, the present inventors show the following general formula,
A method for obtaining an unsaturated polyester having a molecular weight of 5000 or more was found.

That is, the present invention includes (a) an α, β unsaturated polybasic acid or an acid anhydride thereof as one component, and any saturated or unsaturated polybasic acid or an acid anhydride thereof is used in combination with a polyhydric alcohol. To 100 parts by weight of a hydroxyl polyester having an acid value of 15 or less and a number average molecular weight of 500 or more obtained by esterification, (b) 0.01 parts by weight or more of an organotitanium compound catalyst is added, and (c) 0.005 parts by weight or more of The present invention provides a method for producing a high molecular weight unsaturated polyester, which comprises adding phosphorous acid and (d) deglycolizing under reduced pressure of 5 mmHg or less.

An example of the high molecular weight unsaturated polyester obtained in the present invention is shown below in terms of structural formula.

However, G is a residue of α-glycol represented by the following general formula, Here, R ₁ and R ₂ are H or CH ₃ , m = 1 to 9 and n = 9 to
1, M> 20.

What the present invention has found as conditions for synthesizing these high molecular weight unsaturated polyesters is summarized in the following items.

(1) The acid value is 15 or less, preferably 10 or less, the terminal group is substantially a hydroxy group, and the number average molecular weight is 5000.
The above unsaturated polyester is used. This is because if the terminal group is not a hydroxy group, the deglycolization reaction will not be carried out smoothly, and if condensation water is generated by esterification, the activity of the transesterification catalyst used will tend to be impaired. .

When a low molecular weight unsaturated polyester with a molecular weight of 5000 or less is used, it takes a long time to increase the molecular weight by deglycolization reaction (transesterification reaction), which inevitably increases the risk of gelation and stabilizes the product. In addition, it becomes difficult to obtain a high molecular weight unsaturated polyester.

At this time, as described above, even if a large amount (0.05 to 0.5 Phr) of a polymerization inhibitor generally used for gelation prevention, such as hydroquinone, benzoquinone, and phenothiazine, is added, it is hardly useful for gelation prevention.

(2) Add 0.01 parts by weight, preferably 0.05 to 0.5 parts by weight, of a catalyst having a normal transesterification capacity to 100 parts by weight of unsaturated polyester, and (3) deglycolize at a high reduced pressure of 5 mmHg, preferably 1 mmHg or less. I do.

Even if one of the above items is missing, it is difficult to stably obtain a high molecular weight unsaturated polyester.

The reaction temperature can be arbitrarily selected at 170 to 220 ° C, but 180 to 200 ° C is preferable and there is little risk of gelation. At 220 ° C or higher, gelation is inevitable, and at 170 ° C or lower, it tends to be difficult to obtain a practical reaction time.

In addition to the above findings, the present invention is based on the finding that a high molecular weight unsaturated polyester can be synthesized more safely by using an appropriate amount of phosphorous acid together.

The amount of phosphorous acid used is 0.005 parts or more per 100 parts by weight of resin
0.5 parts or less. A desirable amount is 0.01 part or more and 0.1 part or less.

Phosphorous acid may be added from the beginning of the reaction, or may be added simultaneously with the titanium-based catalyst.

The raw materials for synthesizing the high molecular weight unsaturated polyester according to the present invention are no different from those used in conventional polyester resin production.

The raw materials used are, for example, as follows.

(A) As the α, β unsaturated polybasic acid or its acid anhydride, maleic anhydride, fumaric acid, itaconic acid and the like are practically used.

(B) Saturated or unsaturated polybasic acids include those having a benzene nucleus, phthalic anhydride, isophthalic acid,
Terephthalic acid, and dimethyl ester, etc., and as aliphatic cyclic polybasic acid or its acid anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride,
Hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, hettic acid and the like, and further aliphatic dicarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid and the like.

Examples of the halogen-containing acid include tetrachlorophthalic anhydride, tetrabromophthalic anhydride, and the like, in addition to hettic acid.

The polyhydric alcohols used in combination with the above-mentioned polybasic acids typically include the following types.

Ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butanediol 1,3, butanediol 1,4, neopentyl glycol,
Pentanediol 1,5, hexanediol 1,6, and high-boiling point polyhydric alcohols of the following types, which are difficult to exchange with glycol, can be used in a partial combination.

Hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin diallyl ether, trimethylolpropane mono- or diallyl ether.

Further, an alkylene monoepoxy compound can be used. Examples thereof include ethylene oxide, propylene oxide, epichlorohydrin, phenyl glycidyl ether, allyl glycidyl ether and the like.

The esterification in the first step is carried out according to a conventional method in an inert gas stream at 160
It is carried out at a temperature of ~ 230 ° C and an acid value of 15 or less, preferably 10
The following is substantially carried out by synthesizing a hydroxy polyester.

As described above, the number average molecular weight at this time is 1,000 or more.

The deglycolization reaction (transesterification reaction) in the second step is
It is carried out in the presence of a catalyst at a high reduced pressure of 5 mmHg, preferably 1 mmHg or less.

At this time, if the acid value is 15 or more, the deglycolization reaction is not sufficiently carried out, and as a result, it becomes difficult to synthesize the desired high molecular weight unsaturated polyester. As the catalyst, an organic compound of titanium can be used. For example, tetrabutyl titanate, tetrapropyl titanate, titanium acetylacetonate. The amount used is 0.01 to 0.5 part, preferably 0.1 part or more and 0.3 part with respect to 100 parts by weight of the resin.

Styrene is typically used as a monomer for dissolving the unsaturated polyester into a polyester resin, but in addition, vinyltoluene, methyl methacrylic acid diallyl phthalate, diallyl terephthalate, etc. are used.

The high-molecular-weight polyester resin according to the present invention can be utilized in applications where conventional general-type polyester resins have been utilized, in which case fiber reinforcement, filler, colorant, release agent,
Of course, a stabilizer can be used in combination.

〔Example〕

Next, examples will be shown below to help understanding of the present invention.
In the examples, “parts” means “parts by weight” unless otherwise specified.

Example 1 A propylene glycol 350 was placed in a 2 l separable flask equipped with a stirrer, a fractionating condenser, a gas introduction tube, and a thermometer.
g, 332 g of isophthalic acid, esterified at 180-190 ℃ and reacted to an acid value of 27.0, then lowered the temperature to 150 ℃, added fumaric acid 232 g, hydroquinone 0.1 g,
When esterification was continued at 180-190 ° C and the acid value was 9.1 and the number average molecular weight was 1960, tetraisopropyl titanate was used.
2.5g and 0.4g phosphorous acid were added, and at 190-195 ℃, initially 7-10mm
The pressure was reduced to Hg and finally to 0.9 mmHg. The change in the number average molecular weight at this time is shown in FIG.

The system containing this phosphorous acid undergoes stable esterification for 8 hours or more, and the number average molecular weight after 8 hours is about 730
An unsaturated polyester [I] having a weight average molecular weight of 84,000 (Fig. 6) was obtained.

Comparative Example 1 Esterification was carried out under the same formulation and reaction conditions except that phosphorous acid was not added. The change in the number average molecular weight at this time is also shown in FIG.

The system to which phosphorous acid was not added had a number average molecular weight of 6300, a weight average molecular weight of about 120,000, and a tendency of increasing viscosity after a reaction time of 4 hours. Unsaturated polyester [II] was used as the type to which phosphorous acid was not added.

The unsaturated polyester [I] of Example 1 and the unsaturated polyester [II] of Comparative Example 1 are both reddish brown and have a melting point of about 1.
It was 90 ° C.

Dissolve both unsaturated polyesters in styrene separately.
It was a weight% solution.

The one using the unsaturated polyester [I] added with phosphorous acid was designated as the polyester resin (A), and the one using the unsaturated polyester [II] not containing phosphorous acid was designated as the resin (B).

Resin (A), resin (B), 100 parts by weight each,
Add 1.5 parts of methyl ethyl ketone peroxide, 0.3 parts of cobalt naphthenate, gel at room temperature, 80 ℃ for 2 hours, 120 ℃
Cured in 2 hours. Although there were some differences in the viscosity and heat distortion temperature of the resin liquid between the two, they seemed to have almost the same properties (Table 1).

Example 2 A stirrer, a fractionating condenser, a thermometer, and a gas introduction tube were attached.
In a 2 l separable flask, 185 g of propylene glycol,
Ethylene glycol 160g, dimethyl terephthalate 388
g and 2.5 g of zinc acetate were charged, and the reaction was allowed to proceed at 160 to 180 ° C. until no distillation of methanol was observed.

Next, 232 g of fumaric acid was added, and esterification was carried out in a nitrogen stream at 180 to 190 ° C. until the acid value reached 7.8. The number average molecular weight was 2190.

The temperature was lowered to 150 ° C., 0.15 g of hydroquinone, 1.5 g of tetrabutyl titanate and 0.4 g of phosphorous acid were added, and the pressure was reduced to 190 to 195 ° C. and finally to 0.8 mmHg.

Since the resin viscosity in the flask became 79 poises in 8 hours,
It was poured into a metal vat and solidified.

An unsaturated polyester [III] having a reddish brown color, a melting point of about 80 ° C., a number average molecular weight of 7,600 and a weight average molecular weight of 81,000 was obtained.

In addition, except that phosphorous acid was not added, under the same composition and under the same conditions, the resin in the flask showed a tendency to thicken about 4 hours after the start of depressurization, and at this time, the number average molecular weight was 6800 and the weight average molecular weight was 195,000. Met.

Gelation occurred after 4,5 hours.

50 parts of unsaturated polyester [III] was dissolved in 50 parts of styrene to prepare a polyester resin (C) having a viscosity of 21.0 poise. To 100 parts of this polyester resin (C), 1.5 parts of methyl ethyl ketone peroxide and 0.5 parts of cobalt naphthenate were added, gelled at room temperature, and then cured at 80 ° C. for 2 hours and 120 ° C. for 2 hours.

The physical properties of the cured resin are shown in Table 2.

[Advantages of the Invention] Since the present invention is configured as described above, it is possible to provide a novel high molecular weight unsaturated polyester that could not be obtained conventionally, and by utilizing its excellent physical properties, a wide range of applications Can be applied to.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the time and the number average molecular weight under the reaction conditions of a conventional thermoplastic polyester. FIG. 2 is a diagram showing the relationship between time and weight average molecular weight under conventional thermoplastic polyester reaction conditions. FIG. 3 is a diagram showing the relationship between time and number average molecular weight under conventional reaction conditions for unsaturated polyester. FIG. 4 is a diagram showing the relationship between time and weight average molecular weight under the reaction conditions of a conventional unsaturated polyester. FIG. 5 is a graph showing the relationship between time and number average molecular weight in Example 1 and Comparative Example 1. FIG. 6 is the GPC measurement result of the unsaturated polyester of Example 1.

Claims (1)

[Claims] (A) An α, β unsaturated polybasic acid or an acid anhydride thereof is included as one component, and any saturated or unsaturated polybasic acid or an acid anhydride thereof is used in combination with a polyhydric alcohol. To 100 parts by weight of a hydroxyl polyester having an acid value of 15 or less and a number average molecular weight of 500 or more obtained by esterification, (b) 0.01 parts by weight or more of an organotitanium compound catalyst is added, and (c) 0.005 parts by weight or more of A method for producing a high molecular weight unsaturated polyester, which comprises adding phosphorous acid and (d) deglycolizing under a reduced pressure of 5 mmHg or less.