JPH02169616A - Production of curable resin - Google Patents

Abstract

PURPOSE:To obtain a curable resin which is rigid and excellent in heat resistance, elongation and an ability to absorb energy by introducing (co) polymerizable unsaturated bonds into the side chain of a specified graft copolymer. CONSTITUTION:An isocyanate polymer obtained by copolymerizing an unsaturated isocyanate (e.g. isocyanatoethyl methacrylate) with a copolymerizable monomer (e.g. styrene) is polymerized with an active hydrogen monomer reactive with the isocyanate group (e.g. acrylic acid) ad optionally other monomers to obtain a graft polymer having residual isocyanate groups (a) or residual active hydrogen groups (b). This polymer is reacted with an active hydrogen monomer (e.g. 2-hydroxyethyl acrylate when this polymer has component (a) or with an unsaturated isocyanate (e.g. 2,4-tolylene diisocyanate/2-hydroxyethyl methacrylate reaction product) when this polymer has component (b) to introduce (co)polymerizable unsaturated bonds into the side chain of the graft polymer.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention has excellent physical properties that are useful in the fields of fiber reinforced plastics (hereinafter abbreviated as FRP), casting, paints, and adhesives. The present invention relates to a method for producing a radically curable resin. In particular, the present invention relates to a method for producing a curable resin that has excellent heat resistance and mechanical properties.

[Prior art and ili! Radical curable resins include polyester resins, oligoacrylates represented by vinyl ester resins, and diallyl phthalate resins, which are widely used.

Generally speaking, these existing resins are hard, but have a tendency to break brittle, which is a characteristic of thermosetting resins.On the other hand, soft types are rubber-like elastic bodies, but have relatively low strength. Its elongation rate is also not as high as that of rubber.

Vinyl ester resins generally have high strength, and even the hard type exhibits a level of toughness, but it cannot be said that casting resin alone has a large energy absorption capacity.

On the other hand, thermoplastic resins such as ABS have a large impact value and have energy absorption ability, but a common weakness of thermoplastic polymers is that they tend to have large creep when heated.
It is difficult to compare it with thermosetting resins.

The present invention improves the drawbacks of these existing resins and produces a thermosetting resin that is hard, has a high elongation rate, and has energy absorption ability that was not found in conventional resins. It is about the method.

[Means to solve the problem]

The present inventors had previously attempted to establish a method for synthesizing a polymer having (meth)acryloyl groups in the polymer side chain (Japanese Patent Application No. 63-252032), but even with this type of single or copolymerized polymer, It has not always been easy to strike a balance between hardness, heat resistance, and energy absorption ability. Therefore, as a result of further studies, it was discovered that the object could be achieved by the following method, and the present invention was completed.

That is, the present invention provides a polymer having isocyanate groups (III
), a monomer (IV) having an active hydrogen capable of reacting with an isocyanate group, and other monomers as necessary are used in combination to obtain a graft polymer (V), and this graft polymer is composed of (a) residual isocyanate. or (b) has a residual active hydrogen group, and in the case of (a), the monomer further has active hydrogen (V
l) is reacted, and in the case of (b), unsaturated isocyanate (Vll
) to provide a method for producing a curable resin, which comprises imparting a polymerizable or copolymerizable unsaturated bond to the side chain portion of a graft polymer.

By adopting such a method, it has become possible to impart properties that cannot be obtained with a single polymer (including copolymers), such as properties that are hard but have toughness. That is, by changing the type and physical properties of the polymer (III) containing an isocyanate group (hereinafter referred to as a pace polymer) that is first synthesized, and further by reacting and graft polymerizing a monomer having an active hydrogen group, Part of the graft polymer (hereinafter referred to as the side chain part of the graft polymer)
By changing the type and physical properties of the material, it is possible to significantly change its properties.

Therefore, the following types of monomer components constituting the present invention are necessary: (1) unsaturated isocyanate (1v) a monomer having active hydrogen; II).

Examples of unsaturated isocyanates that can be used in the present invention include isocyanate ethyl methacrylate CH river-C0-CHz CHt NCO-isopropenyl-α. Examples include α-dimethylbenzyl isocyanate and methacryloyl isocyanate.

Among them, ease of handling, isocyanate group, r')Ff
.

From the viewpoint of reactivity, isocyanate ethyl methacrylate is preferred.

Although it is not impossible to polymerize the unsaturated isocyanate (1) alone to form a pace polymer (<Iff), it is preferable to copolymerize it with another monomer (II) copolymerizable with it to form a base polymer. The monomers used in these copolymerizations to obtain the desired polymer are not particularly limited, and commercially available monomers can be used as they are.

Examples of these monomers (II) include styrene, vinyltoluene, α-methylstyrene, methyl methacrylate and methacrylic esters, methyl acrylate and acrylic esters, acrylonitrile, methacrylateryl, vinyl acetate and its homologues. , vinyl chloride, vinylidene chloride, butadiene, ethylene, etc.

The proportion of unsaturated isocyanate used in the production of the base polymer is 0.001 parts or more and 10 parts or less, preferably 0.001 parts or more and 10 parts or less per 100 parts by weight of the produced polymer (weight is omitted hereafter).
．． The content ranges from 01 parts to 3 parts, and varies depending on the molecular weight of the polymer.

Examples of monomers having active hydrogen (tV>) include, for example, 2
-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, methylolacrylamide, allyl alcohol, acrylic acid, methacrylic acid, and itaconic acid.

The monomers that are copolymerized with these active hydrogen-containing monomers to obtain the desired polymer are not particularly limited, and the monomers listed above as monomer (+1) can be used as they are.

Existing polymerization methods can be used to polymerize these monomers.

Monomer (Vl) having active hydrogen for reacting with the remaining isocyanate groups of the graft side chain polymer (V)
may be the same as or different from (TV) above, and examples thereof include the same as above.

Unsaturated isocyanate mr for introducing an unsaturated group into the polymer side chain by reacting with the active hydrogen of the grafted partial polymer For example, a type obtained by the following formula can also be used.

(Reaction product of 2,4 tolylene diisocyanate and 2-hydroxyethyl methacrylate) The amount of unsaturated isocyanate reacted with the resulting graft polymer is equal to or less than the mole of active hydrogen in the polymer.

For the reaction between isocyanate and active hydrogen, it is advantageous to use an organic tin compound and tertiary amines, which are generally called urethanization catalysts, and to prevent gelation during the reaction, a polymerization inhibitor is required. It is also effective to use

It goes without saying that the polymer having an unsaturated bond in the side chain according to the present invention can be used in combination with reinforcing agents, fillers, thermoplastic polymers, colorants, mold release agents, etc., as required. For example, organic peroxides, azo compounds, photoreaction initiators, etc. are used.

Next, the present invention will be further explained by examples.

Copolymer of butyl acrylate 1055y, acrylonitrile 80g, and isocyanate ethyl methacrylate 7g synthesized with 50% ethyl acetate solution (
Weigh out 300g of the average molecular weight (approximately 140,000) into a 21 separable flask equipped with a stirrer, fractionation condenser, gas inlet tube, and thermometer, add 936g of styrene, and add approximately 450g of styrene.
Ethyl acetate was distilled off under reduced pressure of Torr, and when the residual ratio of ethyl acetate became 0.5 (%) or less, 130 g of 2-hydroxyethyl methacrylate and styrene lost by volatilization during this operation were removed. In order to replenish 1
05I? was added, and the solid concentration reached 4 at 125-130°C.
After thermal polymerization was carried out in a nitrogen stream until the polymerization concentration reached 8 (%), 0.5 g of hydroquinone was added to stop the polymerization.

Then 140 g of isocyanate ethyl methacrylate,
Dibutyltin dilaurate 511 was added and reacted at 65-70°C under dry air for 5 hours.

As a result of infrared analysis, it was observed that free isocyanate groups had completely disappeared.

A graft type side chain unsaturated polymer (A) was obtained which was slightly cloudy and pale yellow in color and had a viscosity of about 91 voids.

As a comparative example, styrene and 2-hydroxyethyl methacrylate were similarly added to a polymer obtained by copolymerizing 1055y of butyl acrylate and 80y of acrylonitrile without using isocyanate ethyl methacrylate. The polymer was polymerized and reacted with isocyanate ethyl methacrylate to obtain a cloudy liquid unsaturated polymer (B).

100 each of polymer (A) and polymer (B)
Add 1 part of benzoyl peroxide to parts by weight (hereinafter, weight is omitted), cast into a desired mold, and then heat at 80°C for 2 hours and at 120°C.
It was cured by heating for a period of time.

Table 1 shows the physical properties of the cured resin.

Table 1: Mu-Improbenil α,α dimethyl isocyanate produced by emulsion polymerization (Product name: M-TM, manufactured by Shikinichi Yakuhin Co., Ltd.)
An emulsion consisting of a monomer composition of 240 parts by weight (hereinafter, weight is omitted) of I), 1024 parts of butyl acrylate, and 5.3 parts of acrylonitrile was salted out, washed with water, and dried to obtain an acrylic rubber having isocyanate groups (molecular weight: approximately 3).
00,000).

The above acrylic rubber 600 was placed in a 21 separable flask equipped with a stirrer, thermometer, reflux condenser, and gas introduction tube.
fI was weighed, 600 g of methyl methacrylate, 1011 of 2-hydroxyethyl methacrylate, and 5 g of dibutyltin dilaurate were added and dissolved uniformly. After thermal polymerization for 5 hours under reflux of methyl methacrylate in a nitrogen gas stream, the temperature was lowered to 75 0.5 g of methylhydroquinone, 2-
Add 50g of hydroxyethyl methacrylate, 75
The reaction was continued for an additional 5 hours at ~80°C.

As a result of infrared analysis, it was confirmed that free isocyanate groups had disappeared.

50 g of acrylic M and 250 g of methyl methacrylate were added to obtain a graft type unsaturated polymer (C) in the form of a slightly cloudy pale yellow liquid.

The bonded part of two steel plates was prepared by mixing 2 parts of benzoyl peroxide and 0.3 parts of dimethyl paratoluidine with 000 parts of polymer (C000 parts), sanding with #1000 sandpaper, and cleaning with 1,1.1-triclene. Area of 3.2016'
It was coated and bonded together. It was fixed after about 10 minutes, and after being left at room temperature for 24 hours, the adhesive strength by tensile shear reached 214 to 261 kg/c U2.

〔Effect of the invention〕

Since the present invention is constructed as described above, it has a balance between heat resistance and energy absorption ability, and although it is a thermosetting resin, it is hard, has a high elongation rate, and has high energy absorption properties that were not found in conventional resins. This made it possible to produce resin with absorption capacity.

Patent applicant: Showa Kobunshi Co., Ltd.

Claims (1)

[Claims] A polymer (III) containing an isocyanate group, which is obtained by copolymerizing an unsaturated isocyanate (I) with a copolymerizable monomer (II), contains active hydrogen that can react with the isocyanate group. The graft polymer (V) is obtained by polymerizing the monomer (IV) having the above-mentioned monomer (IV) and other monomers as necessary, and this graft polymer has (a) a residual isocyanate group, or (b) a residual isocyanate group. has an active hydrogen group, or in the case of (a), a monomer (V
I) is reacted, and in the case of (b), unsaturated isocyanate (VII) is further reacted.
A method for producing a curable resin, which comprises imparting a polymerizable or copolymerizable unsaturated bond to a side chain portion of a graft polymer by reacting the above.