JPH0747615B2 - Method for producing graft polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a thermoplastic graft polymer which is useful for molded articles of thermoplastics, paints and adhesives.

[Conventional technology and problems]

In recent years, polymers have progressed from homopolymers having a single composition to copolymers and polymer blends with the progress and sophistication of applications, and also graft polymers and block polymers have come to be used. Graft polymers are one of them, and their use is being investigated when mere polymer blends are not expected to improve physical properties.

However, although various methods for forming a graft polymer have been proposed, a simple and reliable method for forming a graft polymer has not been known unexpectedly.

That is, it is difficult to easily and surely form a graft polymer by a typical method such as a method using a macromer, hydrogen abstraction by using a peroxide, and a reaction of an unsaturated epoxy compound. Even if the most reliable method is to use a macromer, its structure and molecular weight are very limited at this stage, and it cannot be generally applied. It is no exaggeration to say that the method of reliably obtaining the desired graft polymer over a wide range is not well established.

[Means for Solving the Problems]

As a result of various studies to obtain a desired polymer which is surely grafted, the present inventors have found that 100 parts by weight of a polymer having at least one active hydrogen in one molecule can react with this active hydrogen. 0.01 to 10 parts by weight of an isocyanate ethyl (meth) acrylate having an isocyanate group is reacted with an unsaturated group-copolymerizable monomer.
It was found that the desired thermoplastic graft polymer grafted reliably can be obtained by adding 10 to 90% by weight and polymerizing, and the present invention could be completed.

In order to help understanding of the present invention, the process is shown as a model in FIG.

In FIG. 1, (A) is a polymer having active hydrogen (for example, a hydroxyl group), which is reacted with the unsaturated isocyanate of (1) to produce a polymer in which the unsaturated isocyanate of (2) is added. . When the unsaturated group of the polymer (2) is reacted with a monomer copolymerizable therewith, for example, styrene, the polymer chain (B) of styrene becomes (1).
A thermoplastic polymer of the present invention, which is grafted to (A) via, is produced.

The polymers usable in the present invention have at least one active hydrogen capable of reacting with an isocyanate in the molecule, and a typical example thereof is a hydroxyl group-containing polymer.

The following various polymers can be used as the hydroxyl group-containing polymer.

(I) 2-hydroxyethyl (meth) acrylate, 2
-A polymer obtained by copolymerizing monomers having a hydroxyl group such as hydroxypropyl (meth) acrylate as one component with other monomers.

(Ii) Phenoxy resin (high molecular weight epoxy resin) (iii) Cellulose ethers, esters thereof, (iv) Polymers obtained by saponifying a polymer containing vinyl acetate as one component, and formalization thereof.
Butyralated polymers, (v) having two or more hydroxyl groups in one molecule,
Thermoplastic polyesters The weight average molecular weight (hereinafter the same) of these polymers is preferably 5000 or more. If the molecular weight is less than this range, it tends to be difficult to obtain a graft polymer having good physical properties.

The functional group having active hydrogen other than the hydroxyl group includes a carboxyl group and an acid amide group, and both can be used, but a polymer containing a hydroxyl group is particularly preferable.

An unsaturated isocyanate for introducing an unsaturated group into a polymer by reacting with a hydroxyl group is represented by the following formula: Isocyanatoethyl methacrylate is convenient.

Adducts of unsaturated alcohols and diisocyanates are also available when the polymer molecular weight is relatively low.

The ratio of the unsaturated isocyanate used depends on the hydroxyl group content of the hydroxyl group-containing polymer and the grafting ratio after the addition of the comonomer, but the polymer 10
0.01 phr or more and 10 phr or less with respect to 0 part, preferably
It is 0.1 phr or more and 3 phr or less. If the amount is less than 0.01 phr, the effect of the present invention will not be exhibited. Also, for more than 10 phr,
It is not preferable because gelation occurs.

The hydroxyl group-containing polymer can be used by dissolving it in a monomer to be grafted onto it or in a solvent, but it is convenient to dissolve it in the monomer and directly proceed to the next step.

The monomers used for the graft polymerization are of the type that are liquid at room temperature or easily liquefy under pressure, and examples thereof include the following types.

Styrene, vinyltoluene, α-methylstyrene, acrylonitrile, methacrylonitrile, methacrylic acid esters, acrylic acid esters, vinyl acetate, vinyl propionate, glycidyl methacrylate, vinylpyrrolidone and the like.

The proportion of the monomer used naturally varies depending on the purpose and required physical properties, but the monomer component is 10 to 90% by weight, preferably 30 to 70 (%) based on the total amount. Outside this range, the effect of the graft polymer is difficult to be exhibited. As the graft polymerization method, existing methods can be applied, and it is not necessary to particularly limit the method.

As a matter of course, the thermoplastic graft polymer according to the present invention can be used in combination with a reinforcing material, a coloring agent, a filler, etc., if necessary.

Next, in order to help understanding of the present invention, examples will be shown below. The parts below are parts by weight unless otherwise specified.

Example 1 A two-separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas introduction tube was used as a saturated polyester, and Chemit R-80 (Hydroxyl value: about 30, molecular weight: about 30) was used as saturated polyester
25000) and 500 parts of ethyl acetate were uniformly dissolved, 4 parts of isocyanatoethyl methacrylate and 0.5 part of dibutyltin dilaurate 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.

Next, butyl acrylate 500 parts, acrylonitrile 40
Part, 31 parts of acrylic acid, and 8 at 70-75 ℃ in a nitrogen stream
After polymerization for an hour, further azobisisobutyronitrile 1.
5 parts was added and polymerization was carried out for 4 hours.

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

(Physical properties of the graft polymer as an adhesive) 150 parts of the syrup-like polymer, 50 parts of ethyl acetate, 2,4
-Mix 1.5 parts of tolylene diisocyanate uniformly and use as sample (A). After applying this to a polyethylene terephthalate film with a thickness of 50μ to a thickness of about 80μ,
Air-dried at 0 ° C for 10 minutes to prepare an adhesive tape.

For comparison, a sample (B) in which isocyanate was similarly added to another 50% (%) ethyl acetate solution of Chemit R-80,
And butyl acrylate 500 parts, acrylonitrile 40
Part, acrylic acid 31 parts copolymer polymer (molecular weight about 9500
A sample (C) was prepared by adding an isocyanate to a 50% ethyl acetate solution of 0), and coating treatment was performed to prepare each adhesive tape.

Each adhesive tape sample was adhered to a stainless steel plate and its strength was measured. The comparison results of the three parties are shown in Table 1, and it was confirmed that the graft polymer was excellent.

Example 2 87 mol% of butyl acrylate obtained by emulsion polymerization method, 10 mol% of acrylonitrile, 3 mol% of 2-hydroxypropyl methacrylate, 200 parts of acrylic rubber having a molecular weight of about 350,000, 840 parts of styrene and 106 parts of acrylonitrile. After dissolving in a mixed monomer, add 0.7 parts of isocyanatoethyl methacrylate and 0.1 part of dibutyltin dilaurate to 70-75
The reaction was carried out at ℃ for 3 hours. As a result of infrared analysis, it was confirmed that the free isocyanate group disappeared.

Then add 10 parts of benzoyl peroxide and add a viscosity of about 1000 at 60 ℃.
After polymerizing until it became a poise, it was transferred to a stainless steel container, filled with nitrogen, and polymerized at 60 ° C. for one day and at 80 ° C. for one day.

After cooling, the obtained lump was crushed and taken out, dissolved in acetone to give a 40% solution, and this was added dropwise to a large amount of water-containing methanol to precipitate the polymer. After this, the block polymer was dried under reduced pressure to obtain a block polymer as a white powder.

The Izod impact strength of the test piece obtained by compression molding using a mold specified in JIS K6911 is 7.6 to 8.9 kgcm / cm.
(With notch). Styrene 840 for comparison
, A thermoplastic polymer prepared in the same manner from 106 parts of acrylonitrile has an Izod impact strength of 1.4 kgcm / cm.
Therefore, the product of the present invention was far superior.

〔The invention's effect〕

Since the present invention is configured as described above, it is possible to reliably produce a polymer in which a desired type of monomer is graft-polymerized in a desired ratio. Therefore, it is possible to produce a thermoplastic graft polymer having excellent physical properties, which cannot be obtained only by a polymer blend of a polymer containing a hydroxyl group and a polymer obtained from a monomer, and to produce a polymer that can be used in a wide range of applications. can do.

[Brief description of drawings]

FIG. 1 shows a model of the production process of a thermoplastic graft polymer. In FIG. 1, (A) is a polymer having active hydrogen,
(1) is an unsaturated isocyanate, (2) is a polymer to which an unsaturated isocyanate is added, and (B) is a polymer chain of a monomer.

Claims (1)

[Claims] 1. To 100 parts by weight of a polymer having at least one active hydrogen in one molecule, 0.01 to 10 parts by weight of an isocyanate ethyl (meth) acrylate having an isocyanate group capable of reacting with this active hydrogen. A method for producing a thermoplastic graft polymer, which comprises reacting and adding 10 to 90% by weight of a monomer copolymerizable with an unsaturated group and polymerizing.