JPS5830903B2 - Odorless solvent-free varnish composition for insulation treatment and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-volatile, odorless, unsaturated polyester-based insulation treatment varnish composition comprising a low-viscosity molecular-terminated allyl-type prepolymer and diallyl isophthalate and/or diallyl orthophthalate. be.

Generally, unsaturated polyester resins are made by dissolving a fumarate or maleate prepolymer in a monomer to form a varnish.

The prepolymer has a large molecular weight and is highly viscous to solid so that the cured product retains particularly toughness and impact resistance.

Further, the unsaturated groups in the prepolymer are difficult to homopolymerize, and are made into a varnish with styrene monomer in order to make the prepolymer liquefiable and easily curable.

These varnishes are widely used as insulation treatment varnishes, but although these varnishes are solvent-free, they are volatile and contain a large amount of styrene monomer, which has a unique strong odor. The odor makes it inferior.

For this reason, it is necessary to introduce large-scale exhaust treatment equipment and incineration equipment in order to ensure occupational safety and health and eliminate pollution.The development of high-performance odorless varnish is extremely important in terms of energy and resource conservation. There is a request.

One possibility for creating a varnish composition that meets these requirements is to use a high boiling point monomer instead of the styrene monomer.

As is well known, styrene monomer is used in a wide range of fields as a raw material for various polymers, and it is desirable to use a monomer that is highly versatile and as inexpensive as possible as an alternative monomer.

In order to realize this possibility and to realize the above-mentioned method for producing an odorless varnish as quickly as possible, the present inventors specifically selected diallyl orthophthalate (boiling point: 158°C/4mmH) as a high-boiling monomer. ) and diallyl isophthalate (boiling point: 182°C/4 mountains H&).

The viscosity of the odorless high-boiling monomer is about 10 centipoise at 30°C, which is higher than that of styrene monomer, and the prepolymer has poor dissolving power. For this reason, the high-boiling monomer must be blended very thickly.

However, in systems containing large amounts of such high-boiling monomers, which tend to undergo degenerative chain transfer, the copolymerization and crosslinking reactivity with maleate or fumarate groups is affected, resulting in cured products with poor balance of properties. You can only get low quality ones.

Therefore, it would be of great industrial significance if a high-performance varnish with low viscosity and excellent workability could be provided by effectively utilizing the highly versatile high-boiling monomer.

The present inventors have thought deeply about the above points, and as a result of intensive research, they have arrived at the present invention as explained below.

The gist of the present invention is a low-viscosity prepolymer produced by a condensation reaction between a monoallyl ester of a dibasic acid (4) and a compound with a hydroxyl group at the end of the molecule (B). The present invention relates to obtaining an odorless varnish that can be cured by blending phthalate and heating in the presence of a polymerization initiator.

The characteristics of the present invention are that the prepolymer has a polymer crosslinking group at the molecular end, so it has good curability, that the unsaturated group is derived from an allyl ester chain member, and that the prepolymer has good curability. Since it has a small molecular weight, it has excellent compatibility with the above-mentioned high-boiling monomers, and the resulting varnish has a low viscosity and good processing workability.

One of the present inventions is a terminal allyl group unsaturated prepolymer (Q
When synthesizing, a polyester polyol having a molecular weight of 200 to 1000 is introduced as a molecular chain member as the molecular terminal hydroxyl group compound (B).

The polyol chain is constructed by esterifying 2 to 1.5 moles of glycol (a) and i,0 moles of dibasic acid (b).

As the glycol (a), for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, triethylene glycol, neopentyl glycol, hydrogenated bisphenol A, etc. are used, and dibasic acids ( b)
Examples include unsaturated dibasic acids (b-1) such as maleic anhydride, itaconic anhydride, and fumaric acid, and/or (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, and lower alkyl esters of these acids; hexahydrophthalic acid; Acids, tetrahydrophthalic acid and anhydrides thereof; adipic acid, cepatic acid, (anhydrous) succinic acid, (anhydrous) malonic acid,
(Anhydrous) 1 such as saturated acid (b-2) such as geltaric acid
Species or mixtures of several species can be used.

The above-mentioned terminal allyl group unsaturated prepolymer (Q is a polyester polyol introduced as a chain member,
A varnish using the prepolymer (Q) has a high degree of freedom in controlling various properties of the cured product over an extremely wide range, and provides a high-performance, well-balanced cured structure.

The second point of the present invention is that the terminal allyl group unsaturated prepolymer (
When synthesizing C), from 50 mol% to 10% of the polyester polyol as the molecular terminal hydroxyl group compound (B)
It is characterized by replacing 0 mol % with glycol chain member (a), and the structure of such a prepolymer (Q has a large effect that it can be made into a low viscosity prepolymer, and this has a ripple effect, such as varnish. Because the concentration of terminal allyl groups in the system can be increased, it is possible to impart extremely rapid curing properties, and because the prepolymer (at stage q) has a low viscosity, it is possible to substantially reduce the amount of high-boiling monomers. This has the advantage of being able to reduce the price by becoming more expensive.

The odorless varnish of the present invention is produced as follows.

First, 1 mole of allyl alcohol and 1 mole of dibasic acid (
Monoallyl ester (4) is synthesized from b).

As the dibasic acid (b), those mentioned above can be used without particular limitation, but it is preferable to use one in the form of anhydride in order to achieve esterification in a short time under a uniform reaction.

In addition, as the acid, unsaturated dibasic acids (
b-2) or the saturated dibasic acid (b-1) may be used alone, or a mixture thereof may be used.

When the amount of unsaturated dibasic acid (b-2) is increased,
The final varnish has rapid curing properties, and the cured product has a high heat distortion temperature and is hard.

On the other hand, when the content of the saturated dibasic acid (b-1) is increased, a varnish having a long pot life can be obtained, and the cured product can also be flexible.

Usually, the monoallyl esterification reaction is carried out at 80 to 110°C.
005 to 0.01% of a polymerization inhibitor, such as hydroquinone, monomethoxyhydroquinone, quinhydrone,
The reaction is carried out in the presence of sulfur, etc., and the end point of the reaction may be determined by acid value measurement or the point at which reflux of allyl alcohol is no longer observed.

Although the product thus synthesized contains, in addition to the monoallyl ester, a small amount of diallyl ester as a by-product or a small amount of dibasic acid as an unreacted product, no special purification means are required.

The reason for this is that the by-product diallyl ester is used as is as a high-boiling monomer, and the unreacted dibasic acid reacts with glycol in the next reaction step and becomes a prepolymer chain member.

The fact that a polymeric crosslinking element can be synthesized by such a simple reaction mechanism can be cited as an excellent advantage of the present invention.

There are two routes for producing the allyl-terminated prepolymer (q) according to the first invention.

One is to first esterify 2 moles of monoallyl ester (4) synthesized as above and 2 to 1.5 moles of glycol (a), and then add 1 mole of dibasic acid (b). In this method, prepolymer 0 is synthesized by reacting (condensation) with polyester polyol, which is prepared in advance by reacting 2 to 1.5 moles of glycol (a) with 1 mole of dibasic acid (b) (B) 1 mole and monoallyl ester (A) 2 moles are esterified to synthesize a terminal allyl group prepolymer (Q).

In the former route, the prepolymer (C) is formed by a one-step reaction.
The prepolymer (C) obtained is essentially the same polyester polyol (C) as in the latter case.
B) It has a chain element in the center of the molecule.

Here, as the glycol (a) and the dibasic acid (b), those mentioned above can be used without particular limitation.

Moreover, the synthesis of the prepolymer (q) can be carried out by a normal esterification reaction, for example, at a reaction temperature of 130 to 1
The reaction is carried out at 80° C. while distilling the produced water out of the system so that the acid value becomes 20 or less.

The terminal allyl group prepolymer synthesized in this way (q is a high-boiling monomer (g)) dissolves in diallyl orthophthalate and/or diallyl isophthalate, resulting in a low-viscosity, odorless varnish.

The high boiling point monomer (b) is blended with the prepolymer (C
) It is preferable to use 50 to 20 parts by weight to 50 to 80 parts by weight.

When the amount of monomer ((t)) exceeds 50 parts by weight, the cured product tends to become brittle due to the highly rigid chemical structure of the monomer.

On the other hand, if the amount of monomer (g) is less than 20 parts by weight, the viscosity of the varnish tends to become slightly high, and for example, it takes a long time to fill the varnish into dense voids during impregnation.

Therefore, the blend of monomers (g) should be selected within the above-mentioned range.

The odorless varnish thus produced uses polymerization initiators such as benzoyl peroxide, dicumyl peroxide, tertiary butyl hydroperoxide, tertiary butyl perbenzoate, tertiary butyl perphthalate,
It can be cured by adding usually 0.5 to 5% by weight of one kind or a mixture of several kinds of organic peroxides such as acetyl peroxide and heating.

Thermal curing conditions vary depending on the heat capacity of the object to be varnished or the amount of varnish to be treated, but are usually 80 to 14
Selected from the temperature range of 0°C.

As mentioned above, the odorless varnish according to the second invention is produced by converting the polyester polyol chain member (B) of the prepolymer (q) into 50 mol% or 100 mol% of glycol ( The main ingredient is a prepolymer with an allyl terminal group having a molecular structure replaced with a).

Here, the above-mentioned replacement by glycol is 50 mol%
In the case of a prepolymer having a smaller molecular structure, the extent to which the above-mentioned favorable ripple effect appears is small.

Therefore, it is recommended that the substitution of chain member (B) with glycol be determined from the above range.

Such a prepolymer (q) was synthesized using 2 moles of monoallyl ester (A) and glycol (a) as in the first invention.
This can be carried out by esterifying 2 moles of the dibasic acid (b) and 0 to 1 mole of the dibasic acid (b).

The terminal allyl group prepolymer (q is a high boiling point monomer) synthesized in this manner because the concentration of unsaturated groups (terminal allyl group) is high and the prepolymer has a small molecular weight, so it has a low viscosity and is a high boiling point monomer. A diallyl (iso)
The phthalate content can be substantially lower than in the first invention, e.g. high boiling monomer □
□□ can be put to practical use even if the weight is 25 to 10 □.

It should be noted that other prepolymers or monomers, such as epoxy acrylate, epoxy methacrylate, glycol or polyester polyol di( It does not depart from the scope of the present invention to add small amounts of meth)acrylate, unsaturated urethane resin, glycidyl (meth)acrylate, allyl glycidyl ether, etc.

EXAMPLES The present invention will be explained in more detail below with reference to Examples, but it should be understood that the present invention is not limited to these examples.

Example 1 (a) Synthesis of monoallyl ester In a fourth flask (0,5A), 2 moles of allyl alcohol (11L9), 1 mole of maleic anhydride (98,9), and 1 mole of succinic anhydride (100fi) were added. Add 0.05% by weight of hydroquinone and heat at 100 to 140℃ for 3
A mixed monoallyl ester was synthesized by reacting for ~6 hours.

(b) Synthesis of polyester polyol 1 piece of propylene glycol in 4 bottles (0,51)
．． 75 moles (133 g), 0.25 moles of succinic anhydride (
25,! 17), maleic anhydride 0.75 mol (73,
5,9) and 0.025% by weight of hydroquinone, and after refluxing at 130 to 150°C for 1 hour, the temperature was raised while distilling off the produced water, and at 180 to 200°C, it was heated to about 95% or more of the theoretical amount. The water produced by the reaction was taken out.

The acid value of the obtained polyester polyol was 4.7, and the molecular weight measured by the freezing point depression method was 740.

(c) Production of odorless varnish In a fourth flask (0,57), 0.5 mol (78.5 g) of the monoallyl ester obtained in (a) and 0.25 mol (0.25 mol) of the polyester polyol obtained in (b) 185 g) was charged, and the water produced by the reaction was distilled out of the system at 120 to 160°C.

After removing 95% or more of the theoretical amount of reaction water, nitrogen gas is strongly blown into the reactor.

The terminal allyl group prepolymer thus obtained has an acid value of 8 and has a starch syrup-like appearance at room temperature.

Diaryl isophthalate 3 is added to 65 parts by weight of the prepolymer.
When 5 parts by weight are added and dissolved homogeneously, it is odorless and has a viscosity of 9.5.
It is a poise (25°C) varnish.

The varnish contains 1. dicumyl peroxide as a polymerization initiator.
5% by weight was added, the mixture was inserted between two glass plates (spacer cap Q, 2 mm) to which a Teflon sheet was attached, and the mixture was heated and cured at 145° C. for 3 hours to obtain a cured product in the form of a film.

The thus obtained cured product had a gel fraction of 98.7%,
Its mechanical properties were a tensile strength of 7.5 kg/ma and an elongation rate of 4%.

The gel fraction was determined by precisely measuring 1 g of the cured product, extracting it for 8 hours at the boiling point of ethyl acetate using a Soxhlet extractor, and then determining the weight loss of the film after vacuum drying.

The mechanical properties were measured at room temperature according to the method of JIS K6781 at a tick interval of 7 cIrL1 and a tensile rate of ICrrL/min.

In order to compare and examine the performance of the odorless varnish produced according to the present invention, the following experiment was conducted.

That is, the polyester resin 65 synthesized in (b) above
The varnish containing 35 parts by weight of diallyl isophthalate was odorless but had a viscosity of 11 lbs. (at 25°C).
Met.

The varnish was cured in the same manner as in Example 1, and the properties of the cured product were measured. The gel fraction was as low as 75%, and the tensile strength was 1.5 kg/myi1, and the elongation rate was 1.
．． It was at a low level of 9%.

Furthermore, the polyester resin synthesized in (b) above and (
The varnish prepared by dissolving the allyl-terminated prepolymers synthesized in step (c) in styrene naturally gave off an unpleasant odor.

Example 2 2 moles (3t4.9) of the monoallyl ester synthesized in Example 1 (a) in a four-loaf flask ([)! :Propylene glycol 1 mol (76g), ethylene glycol 1
mol (62,!9), phthalic anhydride 0.3 mol (54,
4,9) and 0.2 mol of maleic anhydride (19,6,
! 9) and hydroquinone 0.025%, 130
After refluxing at ~150°C for about 2 hours, the temperature was raised while distilling the produced water out of the system, and the theoretical amount of 95%
After removing more than % of the reaction water, nitrogen gas is strongly blown into the reactor.

The terminal allyl group prepolymer thus obtained had an acid value of 5.
2 and the viscosity was 57 poise (25°C).

Diaryl isophthalate 2 is added to 80 parts by weight of the prepolymer.
Those containing 0 parts by weight are odorless and have a viscosity of 1i2. o Poise (
25°C) low viscosity varnish.

A film obtained by curing the varnish in the same manner as in Example 1 had a gel fraction of 99.0% and a tensile strength of 8.7k.
g/vt4, and elongation rate was 3.2%.

Claims (1)

[Claims] 1. 2 moles of monoallyl ester of dibasic acid and a molecular weight of 2
Terminal allyl group unsaturated prepolymer 5 obtained by esterifying 1 mol of polyester polyol of 00 to 1000
0 to 80 parts by weight, (1) 50 to 20 parts by weight of diallyl isophthalate and/or diallyl orthophthalate, and (2) 0.5 to 2% by weight of a polymerization initiator to this blend. varnish composition. 2. 1 of the polyester polyols with a molecular weight of 200 to 1000, which are constituent components of the terminal allyl group unsaturated prepolymer.
The odorless varnish composition according to claim 1, wherein 00 to 50 mol% is replaced with glycol.