JPH07108932B2 - Method for producing curable graft resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a radical having excellent physical properties useful in various fields such as fiber reinforced plastics (hereinafter abbreviated as FRP), casting, coating, and adhesion. The present invention relates to a method for producing a curable resin. In particular, the present invention relates to a method for producing a thermosetting resin which is excellent in heat resistance and various mechanical properties.

[Conventional technology and problems]

Radical curable resins include polyester resins, oligoacrylates represented by vinyl ester resins, and diallyl phthalate resins, all of which are widely used.

These existing resins are generally peculiar to thermosetting resins, and the hard type has a tendency to be hard but brittle fracture, while the soft type is a rubber-like elastic body, but has relatively low strength. The elongation is not as great as rubber.

Vinyl ester resins are generally high in strength and exhibit some toughness even in a hard type, but it cannot be said that a cast resin alone has a large energy absorption capacity.

On the other hand, a thermoplastic resin, such as ABS, has a large impact value and has an energy absorbing ability, but a common weak point of thermoplastic polymers is that creep during heating is large,
It is difficult to compare with thermosetting resins.

The present invention improves the drawbacks of these existing resins, and produces a resin which is thermosetting and has a high elongation and energy absorption capacity, which cannot be seen in the conventional resins. It is about the method.

[Means for Solving the Problems]

The present inventors have previously established a method for synthesizing a polymer having a (meth) acryloyl group in the polymer side chain (Japanese Patent Application No. 63-252032). However, even with this type of homo- or copolymer polymer, However, it has not always been easy to balance heat resistance and energy absorption capacity. Therefore, as a result of further studies, it was found that the object could be achieved by the following method, and the present invention could be completed.

That is, in the present invention, at least 1 active hydrogen is contained in one molecule.
To the polymer (I) having an unsaturated isocyanate (I
I) is reacted, vinyl monomer (III) and, if necessary, an unsaturated compound (monomer) having active hydrogen are added to carry out polymerization, and the resulting polymer is reacted with unsaturated isocyanate (IV). The present invention provides a method for producing a curable graft resin, which comprises:

By adopting such a method, it becomes possible to impart a property that cannot be obtained by a single polymer (including a copolymer), for example, a property that is hard but has toughness.

That is, the combination of the hardness and softness of the base polymer, the hardness and softness of the polymer forming the grafted portion,
We were able to realize the addition of various physical properties that could not be achieved with a single polymer containing a copolymer.

The main components of the present invention are roughly classified into the following four types.

(I) A polymer having at least one active hydrogen capable of reacting with an isocyanate group in one molecule (abbreviated as a base polymer).

The polymers belonging to this are typically classified into the following three types.

(A) A copolymer obtained by copolymerizing a monomer having an active hydrogen-containing functional group, for example, a hydroxyl group in the molecule, as a component with a desired monomer.

Examples of the monomer having active hydrogen forming these polymers (hereinafter referred to as a specific monomer) include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate,
Examples thereof include 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, methylol acrylamide, allyl alcohol, acrylic acid, methacrylic acid, and itaconic acid.

The monomers to be copolymerized with these specific monomers to obtain a desired polymer are not particularly limited, and commercially available products can be used as they are.

Examples thereof are styrene, vinyltoluene, α-methylstyrene, methyl methacrylate and methacrylic acid esters, methyl acrylate and acrylic acid esters, acrylonitrile, methacrylonitrile, vinyl acetate and its homologues, vinyl chloride, Vinylidene chloride, butadiene, ethylene and the like.

The above-mentioned specific monomer and the ratio of the monomer used are 0.01 mol (%) to 30 mol (%) of the specific monomer, preferably 0.1 mol (%).
It is from 20 mol (%) to 20 mol (%). It is sufficient for the specific monomer to be present as long as the necessary amount of unsaturated isocyanate is bonded, and the excess amount may adversely affect the physical properties of the polymer.However, when the unsaturated isocyanate is further reacted after the synthesis of the graft polymer. There is also.

(B) Polymers that do not initially have active hydrogen, but have become active hydrogen by methods such as hydrolysis and transesterification.

For example, a polymer obtained by a method such as hydrolysis of a polymer containing vinyl acetate as at least one component, or transesterification by addition of alcohol, or a derivative thereof, such as polyvinyl formal, polyvinyl acetal, polyvinyl butyral, and ethylene-vinyl acetate copolymer. Saponified product of type soluble in solvent or monomer.

(C) a polymer having a hydroxyl group in the molecular structure,
For example, (a) phenoxy resin (high molecular weight epoxy resin) (b) cellulose derivative ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate and the like.

(II) Unsaturated Isocyanate As an unsaturated isocyanate for reacting with the active hydrogen of the above-mentioned base polymer to form an active site for grafting, an unsaturated bond and an isocyanate group are shared in the same molecule. Type, eg, isocyanatoethyl methacrylate And methacryloyl isocyanate Etc. are suitable.

The proportion of unsaturated isocyanate used is based on 100 parts by weight of the base polymer having active hydrogen (weight is omitted below).
The amount is 0.001 part or more and 10 parts or less, preferably 0.01 part or more and 3 parts or less, and varies depending on the molecular weight of the polymer.

(III) Monomer component of graft part As the monomer component for forming the graft part of the present invention, the various monomers described in (I) can be used as they are.

By reacting the base polymer with unsaturated isocyanate,
One of the conditions of the present invention is to dissolve a polymer into which an unsaturated bond has been introduced into a solvent or a monomer and form a polymer of a graft portion by polymerizing an added monomer.

In the present invention, active hydrogen capable of reacting with an isocyanate group can also be introduced into this graft portion.

As the polymerization method, existing polymerization methods such as bulk polymerization, solution polymerization, pearl polymerization and emulsion polymerization are used.

The ratio of the component of the base polymer (I) to the monomer component of the graft portion of (III) obviously varies depending on the purpose of use, but as a base polymer component 95 to 5
The weight (%) is preferably 80 to 20% by weight, and the remaining amount (%) is almost a graft polymer component.

If it is out of this range, the meaning of forming a graft polymer becomes poor.

(IV) Unsaturated Isocyanate In order to introduce an unsaturated bond into the base polymer portion and / or the graft polymer portion, in addition to the unsaturated isocyanate used to form the cross-linking point of the base polymer for graft polymerization. In addition, unsaturated isocyanates are used.

As this type, in addition to the above-mentioned unsaturated isocyanate, 1 mol or more and 1.6 mol or less of unsaturated monoalcohol are reacted with 1 mol of diisocyanate to leave 0.4 equivalent or more and 1 equivalent or less of isocyanate group remaining. Different types are also available.

In this case, as the diisocyanate, isocyanates such as 2,4-tolylene diisocyanate and isophorone diisocyanate having different reactivity of two isocyanate groups are advantageous, but other diisocyanates are also preferable. It is available.

It is practical to use a reaction catalyst for the reaction between the unsaturated isocyanate and the active hydrogen in the polymer.

The resin obtained by the present invention can be used in combination with a reinforcing material, a filler, a colorant, a release agent, a thermoplastic polymer, or an oligomer, if necessary, and a radical-generating catalyst is used for curing at room temperature, Either heating, light or electron beam is used.

Next, the present invention will be further described with reference to examples.

Example 1 Synthesis of Graft Polymer (A) An acrylic rubber having a molecular weight of about 300,000, which was synthesized by an emulsion polymerization method as a base polymer, and was precipitated and dried (83 mol% butyl acrylate, 10 acrylonitrile).
(Mole%, 2-hydroxypropylmethacrylate 3 mole% composition) 200 g was weighed and charged into a 3 l separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas introduction tube, and further styrene. Add 832 g and acrylonitrile 53 g and heat to 60-65 ℃ to dissolve uniformly.

Next, 0.5 cc of isocyanate ethyl methacrylate (approx.
0.55g), dibutyltin dilaurate 1g, 60-65 ℃
And reacted for 3 hours. In this way, the side chain (meta)
A styrene / acrylonitrile mixed monomer solution (B) of an acrylic rubber having an acryloyl group was obtained.

As a result of infrared analysis, it was confirmed that in this B, the free isocyanate group disappeared.

Next, after adding 144 g of 2-hydroxypropyl methacrylate and thermally polymerizing at 120 to 125 ° C. in a nitrogen stream for 5 hours,
570 g of ethyl acetate and 12 g of azobisisobutyronitrile were added, and the mixture was polymerized at 70 to 75 ° C for 10 hours.

The polymerization rate was estimated to be about 93% by the volatilization method. Polymerization was stopped by adding 0.6 g of hydroquinone. Further, 155 g of isocyanate ethyl methacrylate was added, and the mixture was reacted at 70 to 75 ° C for 5 hours. As a result of infrared analysis, it was confirmed that the free isocyanate group had disappeared. To this, 300 g of styrene was added, and about 200 cc of ethyl acetate was distilled off under reduced pressure of 500 to 550 mmHg, then 370 g of styrene was added, and the remaining amount of ethyl acetate was distilled off under reduced pressure again. GPC
It was discontinued when the analysis showed 0.4 (%) or less, and 630 g of styrene was added to obtain a styrene solution of the graft polymer (A). This A had a viscosity of 13.1 poise and a slightly cloudy pale yellow color.

Separately, styrene 832g, acrylonitrile for comparison
After heat-polymerizing a mixed monomer of 53 g and 2-hydroxypropyl methacrylate 144 g at 120 to 130 ° C. to prepare a monomer solution of a polymer having a polymerization rate of about 46%, 155 g of isocyanate ethyl methacrylate, 3 g of dibutyltin dilaurate, 0.5 g of methyl parabenzoquinone. g was added, and the mixture was reacted at 65 to 70 ° C for 5 hours. Thus, a resin (C) having an unsaturated bond in its side chain was obtained. Infrared analysis of this (C) revealed that the free isocyanate group had disappeared. The viscosity was about 51 poise.

The graft polymer (A) of the present invention thus obtained, and the resins (B) and (C) as comparative examples, and the resin (B) and the resin (C) are also added.
1% benzoyl peroxide was added to each of the 50/50 wt% mixed resins (white turbidity), and the mixture was heated at 80 ° C. for 1 hour and at 120 ° C. for 8 hours for curing to determine the physical properties. The results are shown in Table 1. As can be seen, the graft polymer (A)
It is understood that is excellent in the balance of physical properties.

Example 2 Synthesis of Graft Polymer (E) In a 3 l separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas introduction tube, as a saturated polyester,
Toray Industries, Ltd. Chemit R-80 (Hydroxyl value approx. 30, molecular weight approx. 2500)
After uniformly dissolving 500 parts of 0) and 500 parts of ethyl acetate,
Isocyanatoethyl methacrylate (4 parts) and dibutyltin dilaurate (0.5 parts) were added, and the mixture was reacted at 70 to 75 ° C for 5 hours. As a result of infrared analysis, it was confirmed that the free isocyanate group disappeared. Then butyl acrylate 500 parts,
After adding 27 parts of acrylonitrile, 65 parts of 2-hydroxyethyl methacrylate and 5.7 parts of azobisisocybutyronitrile and polymerizing in a nitrogen stream at 70 to 75 ° C for 8 hours, 1.5 parts of azobisisobutyronitrile is further added for 4 hours. Polymerized.

A slightly cloudy syrupy polymer (ethyl acetate solution) was obtained.

Next, add 70 parts of isocyanate ethyl methacrylate, 620 parts of ethyl acetate and 2 parts of dibutyltin dilaurate,
The reaction was carried out at 0 to 75 ° C for 5 hours to obtain a graft type unsaturated polymer (E) (white turbidity). As a result of infrared analysis of this E, it was confirmed that the free isocyanate group disappeared. The viscosity was 79 poise. To 100 parts of this graft-type unsaturated polymer (E), 1 part of tert-butyl peroctoate was added as a peracid, and applied to a polyester film having a thickness of 50μ to give 50μ, and dried at 80 ° C for 10 minutes. Then, it was used as a test piece as an adhesive tape.

For comparison, unsaturated polymer (F) obtained by reacting Chemit R-80 with IEM, and 500 parts of butyl acrylate,
Unsaturated polymer (G) obtained by reacting a polymer synthesized from 27 parts of acrylonitrile and 65 parts of 2-hydroxyethyl methacrylate with 70 parts of isocyanate ethyl methacrylate.
Was adjusted, and similarly applied and dried to obtain a sample tape.

Adhere each test specimen adhesive tape to the stainless steel plate,
After press molding (pressure 5 kg / cm ² ) at 120 ° C. for 5 minutes to cure, physical properties were measured.

The results are shown in Table 2 together with the strength before curing. As can be seen, the unsaturated graft polymer (E) is
The physical properties were well balanced and good.

Example 3 Synthesis of Graft Polymer (H) A 3 l separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas inlet tube was charged with a phenoxy resin [Yukaka Shell Epoxy Co., Ltd. "Epicote OL-53-BH-35 "(Methyl ethyl ketone solvent, solid content about 35%, polymer molecular weight about
55000)], 800 parts, isocyanatoethyl methacrylate 2.5 parts, and dibutyltin dilaurate 0.5 parts,
The reaction was carried out at ℃ for 3 hours. As a result of infrared analysis, the product was found to have lost the free isocyanate group.

Then, isobutyl methacrylate 113 parts, methyl methacrylate 20 parts, 2-hydroxypropyl methacrylate 14 parts
Part, azobisisobutyronitrile 1 part, and polymerized in a nitrogen stream at 65 to 70 ° C., and when the polymerization rate became almost 50%, 153 parts of methyl ethyl ketone and 0.5 part of azobisisobutyronitrile were further added, Furthermore, it reacted until the polymerization rate became about 90%.

Polymerization was stopped by adding 0.05 part of methylparabenzoquinone.

Separately prepared unsaturated isocyanate (an addition product of 1 mol of isophorone diisocyanate and 1.3 mol of 2-hydroxyethyl methacrylate, 0.7% of unsaturated isocyanate and 50% methyl ethyl ketone containing 0.3 mol of unsaturated diurethane). (Solution) (360 g) was added and the mixture was reacted at 65 to 70 ° C. for 5 hours to give a slightly cloudy pale yellowish brown unsaturated polymer (H) (methyl ethyl ketone solution). This H
As a result of infrared analysis, it was confirmed that the free isocyanate group disappeared.

To this unsaturated polymer H, as a photopolymerization initiator, "Darocure # 1173", a product of Merck Co., was added in an amount of 1 part per 100 parts of the unsaturated polymer (H) (methyl ethyl ketone solution) so that 100 µm was obtained on the Bonderite steel plate. After coating with a bar coater, the solvent was volatilized by heating at 80 ° C. for 2 hours.

Irradiation energy of about 2000 mJ / cm ² was applied to cure the coating film.

The pencil hardness of the coating film is 2H, and the adhesion test is 100 /
No cracks or peeling were found in the 100 and 90 degree bending tests.

〔The invention's effect〕

Since the present invention is configured as described above, it is a thermosetting resin that balances heat resistance and energy absorption capacity, and is hard to be found in conventional resins, yet has high elongation and energy. It is possible to produce a resin having an absorption capacity.

Claims (1)

[Claims] 1. 100 parts by weight of a polymer (I) having at least one active hydrogen in one molecule is reacted with 0.001 to 3 parts by weight of an unsaturated isocyanate (II), and a vinyl monomer (III), And a method for producing a curable graft resin, which comprises adding an unsaturated compound (monomer) having active hydrogen to carry out polymerization, and reacting the obtained polymer with an unsaturated isocyanate (IV).