JPH05163358A - Coating material resin and its production - Google Patents

Abstract

PURPOSE:To provide the title material which is free from the problem caused by a decrease in solubility and an increase in solution viscosity, can well disperse solid particles and can form a coating film excellent in mechanical properties and adhesion to the surface of a substrate when used as a film-forming component of a coating material. CONSTITUTION:The title resin comprises a polyacryl-polyurethane diblock copolymer or a polyacryl-polyurethane-polyacryl triblock copolymer each of which contains polar groups in the molecule.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin useful as a film-forming component for coating materials such as various paints and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, polyurethane-based resins, vinyl chloride-based resins, etc. have been used as film-forming components for various coating materials.
Various synthetic resins such as fibrin resin, polyvinyl butyral resin, polyester resin, polyacrylic resin, epoxy resin, and phenol resin are used. Among them, polyurethane resin is It is known to form a film which is flexible and has good mechanical properties.

However, a coating material using a usual polyurethane resin has insufficient adhesion to the surface to be coated, and solid particles such as pigments, fillers, aggregates, metal powders, magnetic powders, etc. When included, there is a problem that the dispersibility of these solid particles is poor.

Therefore, in recent years, polyurethane resins in which polar groups such as a carboxyl group, a sulfonic acid group, a phosphoric acid group, a tertiary amino group and a hydroxyl group are introduced into the molecule of polyurethane have appeared. According to the polyurethane-based resin containing such a polar group, when it is used as a film forming component of the coating material, due to the strong adsorption action of the polar group on the solid particle surface and the coated surface,
The advantages are that the dispersibility of the solid particles in the coating material is improved and the adhesion of the formed film to the coated surface is improved.

[0005]

However, in the above-mentioned conventional polyurethane-based resin containing a polar group, if the hard component in the molecule is increased in order to further improve the mechanical properties, the solubility decreases and -Since the preparation of the coating material is difficult and the viscosity of the solution is remarkably increased to deteriorate the coating property, there is a problem that the application field of the coating material using the coating material is limited.

[0006] In view of the above situation, the present invention is free from problems such as the decrease in solubility and increase in solution viscosity of the above-mentioned conventional polyurethane resins when used as a film forming component of a coating material, An object of the present invention is to provide a coating material resin capable of obtaining good dispersibility of particles and capable of forming a film having excellent mechanical properties and adhesiveness to a coated surface, and a method for producing the same.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have introduced a polar group into a copolymer in which an acrylic component and a urethane component are bonded in a specific form. According to the resin described above, a coating material having a low viscosity and good coatability can be easily prepared, the dispersibility of solid particles in the coating material becomes good, and the resin has excellent mechanical properties. The inventors have found that a coating film having good adhesion to the surface to be coated can be formed, and completed the present invention.

That is, the present invention comprises a polyacrylic-polyurethane diblock copolymer or a polyacrylic-polyurethane-polyacrylic triblock copolymer, and is characterized by containing a polar group in the molecule. -It relates to the resin for the towing material.

In the present invention, the polyacrylic component of the copolymer is 10 to 5 as the above coating material resin.
The composition occupying the range of 0% by weight, and the number average molecular weight of the polyacrylic component of the copolymer is 1,000 to 10,000.
A configuration of 0 is a preferable mode.

Furthermore, the method for producing a coating material resin according to the present invention comprises a one-end reactive acrylic polymer,
It is characterized in that the above-mentioned diblock copolymer or triblock copolymer is synthesized by a reaction with a urethane polymer reactive at both ends.

[0011]

Since the coating material resin of the present invention is a diblock copolymer or a triblock copolymer of a polyacrylic component and a polyurethane component, it has a hard property of the polyacrylic component and a toughness of the polyurethane component. It also has the property of being easily stretched, and exhibits a strong adsorptive effect on the surface of solid materials in the solution state due to the polar groups contained in the molecule of this copolymer, and it is also well soluble in various solvents used for general coating materials. To give a low viscosity solution.

Therefore, by using this resin, a coating material having a low viscosity and good coatability can be easily prepared, and at the same time, a pigment, a filler, an aggregate, a metal powder is added to the coating material. In the case of containing solid particles such as magnetic powder, abrasive, and conductive particles, the dispersibility of these particles becomes good. Further, the formed film has excellent mechanical properties in which the properties of both components of the copolymer are appropriately harmonized, has a very high elasticity, is tough and is not easily broken, and is not coated. In the case of showing strong adhesion to the surface and not causing delamination and containing solid particles, the particles are uniformly dispersed in the coating film.

By the way, it is considered that the formation of a pseudo network structure based on the aggregation of the hard components in the polymer molecule is greatly involved in the development of the elasticity-rich property of ordinary polyurethane resins. Also in the coating material resin of the present invention, it is necessary to facilitate generation of a similar pseudo-network structure in order to impart high elasticity. For this reason, the above block copolymer is a polyacrylic-polyurethane diblock form or It takes the form of a triblock of polyacrylic-polyurethane-polyacrylic.

That is, in such a diblock or triblock copolymer, the hard polyacrylic component is located on the end side of the polymer molecule and has a high degree of freedom, so that a pseudo network structure is likely to be formed due to aggregation, and the diblock Since the main part of the copolymer or the middle part of the triblock copolymer is composed of a highly stretchable polyurethane component, as a whole it exhibits significantly higher elasticity than conventional polyurethane resins. ..

The coating material resin of the present invention includes various kinds of polyacryl components and polyurethane components constituting the block copolymer and ratios of the two components are different from each other. It may have a polyurethaneurea structure containing a bond. However, if the proportion of the polyacrylic component in the block copolymer is too low, its hard properties will not be sufficiently expressed, and conversely if it is too high, the toughness and elongation properties based on polyurethane will be difficult to be exhibited, and the copolymer will not be exhibited. The ratio of the polyacrylic component in the composition is preferably in the range of 10 to 50% by weight, and particularly preferably in the range of 20 to 45% by weight.

The number average molecular weight of the polyacrylic component is preferably in the range of about 1,000 to 10,000 in order to exert high elasticity due to the above-mentioned pseudo network structure. If the number average molecular weight is too large or too small, the polyacrylic component is less likely to aggregate, which is not preferable.

Further, if the number average molecular weight of the coating material resin as a whole is too small, the mechanical properties are insufficient, and conversely, if it is too large, the solution viscosity when dissolved in an organic solvent is high. Therefore, 3,000 to 100,000
The range is preferably about 10,000 to 50,
A range of 000 is preferred.

On the other hand, as polar groups to be introduced into such a coating material resin, --SO ₃ M group and --OSO ₃ M group are used.
Group, —COOM group, —PO (OM) ₂ group (provided that M is a hydrogen atom, an alkali metal atom or a hydrocarbon group), a tertiary amino group, a hydroxyl group, etc., and these are in the molecule of the block copolymer. It may contain two or more kinds. The position of introduction of these polar groups may be anywhere in the block copolymer, and the polar group may be present in only one of the polyacrylic component and the polyurethane component, or the polar group may be present in both of these components. Good.

The introduction amount of the polar group is such that the polar group is --SO.
₃ M group, -OSO ₃ M group, -COOM group, -PO (O
M) When it is either a ₂ group or a tertiary amino group, the content thereof in the block copolymer is preferably 0.0001 to 0.5 mmol / g. If the content is too small, the dispersibility of the solid particles in the coating material and the adhesion to the surface to be coated become insufficient, and conversely if the content is too large, the solution viscosity increases due to aggregation of polar groups. Invite. Further, the content in the block copolymer when the polar group is a hydroxyl group, the increase of the solution viscosity is small at most, but if too small, the dispersibility and adhesiveness similar to the above becomes insufficient, 0.05
The amount is preferably at least mmol / g, particularly preferably at least 0.5 mmol / g.

The means for synthesizing such a coating material resin is not particularly limited, but as a simple method, the following (A) and (B) components; (A) one end reactive acrylic polymer (B) A method of reacting a urethane polymer reactive at both ends to synthesize the above-mentioned diblock copolymer or triblock copolymer is recommended. In addition,
The terminal reactive group of the component (A) is preferably an amino group, a hydroxyl group, a carboxyl group or the like, whereas the both terminal reactive groups of the component (B) is preferably an isocyanate group.

Here, the one-terminal-reactive acrylic polymer as the component (A) can be synthesized, for example, by radically polymerizing an alkyl (meth) acrylate with a chain transfer agent having a reactive functional group. .. In this synthesis, by using an acrylic monomer containing a polar group together with (meth) acrylic acid alkyl ester,
It is possible to obtain a one-end reactive acrylic polymer containing a polar group.

Preferred examples of the above-mentioned (meth) acrylic acid alkyl ester include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate and lauryl. Methacrylate, stearyl methacrylate, etc. may be mentioned, and these may be used in combination of two or more kinds.

As the polar group-containing acrylic monomer, acrylic acid, methacrylic acid, dimethylaminoethyl methacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid, methacryloxyethylsulfonic acid can be used. , 2-methacryloxyethyl citrate phosphate, 2-hydroxyethyl methacrylate, and the like, and these may be used in combination of two or more kinds. Furthermore, it is also possible to copolymerize these monomers with a monomer having a reactive functional group such as glycidyl methacrylate and to introduce a new polar group by reacting the reactive functional group with another compound. It is possible.

Examples of the chain transfer agent having a reactive functional group include mercaptoethanol, aminoethanethiol, thioglycolic acid and mercaptopropionic acid.

The above (meth) acrylic acid alkyl ester and the polar group-containing acrylic monomer are radically polymerized using the above chain transfer agent, and the reactive end of the obtained polymer is reacted with another compound. A new terminal reactive group may be introduced.

On the other hand, the urethane polymer reactive at both ends of the component (B) has an organic diisocyanate compound, a polyol and, if necessary, a chain extender, and an isocyanate at both ends.
It is possible to synthesize by reacting so that the residual group remains.

At this time, by using a compound having a polar group as a part or all of each reaction component, particularly a polyol or a chain extender, both-end reactivity or one-end reactivity having a polar group in the molecule is used. It is possible to obtain the urethane polymer of. When water or a diamine is used as the chain extender, the urethane polymer has a polyurethane urea structure containing a urea bond.

Examples of the above organic diisocyanate compound include tolylene diisocyanate, 4 · 4′-
Diphenyl methane diisocyanate and hexamethylene diisocyanate are preferably used.

As the polyol, there may be mentioned carbon dioxide such as poly 1.6-hexane carbonate.
Polyolefin diol such as polybutadiene diol and hydrogenated butadiene diol, polycaprolactone diol such as 1,6-hexamethylene lactone diol, poly ε-caprolactone diol, polyethylene glycol
Polyether such as polypropylene, polypropylene glycol, polybutylene adipate, polybutylene phthalate
Polyester diol and the like such as gato are preferably used. Further, it is also possible to use a diol having a polar group, a polyester diol having a polar group in the molecule synthesized using a dicarboxylic acid, and the like.

As the chain extender, ethylene glycol,
1.3-propanediol, 1.3-butanediol, 1
.Diols such as 4-butanediol and neopentyl glycol, diamines such as ethylenediamine and tolylenediamine, those having no polar group such as water 2.2
Polar groups such as dimethylolpropionic acid, sodium bis (4-hydroxybutyl) -5-sulfoisophthalate, sodium β-glycerophosphate, N-methyldiethanolamine, potassium 2,3-dihydroxy-1-propanesulfonate There are those that have.

The types and use ratios of these organic diisocyanate compounds, polyols, and chain extenders depend on the desired physical properties, adhesiveness, dispersibility, etc. of the finally synthesized block copolymer. And adjust accordingly.

To prepare a coating material using the coating material resin of the present invention, the above-mentioned polyacrylic-polyurethane diblock copolymer or polyacrylic-polymer is used.
Coating material resin consisting of polyurethane-polyacrylic triblock copolymer, and other binder resin to be blended as necessary, and necessary additives such as various solid particles are added to the organic solvent to dissolve the resin component. do it. A desired coating film can be formed by applying or spraying this liquid onto a target surface to be coated.

Examples of the above-mentioned other binder resins include polyurethane resins, vinyl chloride resins, fibrin resins, polyvinyl butyral resins, polyester resins, polyacrylic resins, epoxy resins, Examples thereof include phenol resins, polyisocyanate compounds as cross-linking agents, and the like which have been conventionally used as binders for general coating materials. These can be used with good compatibility with the coating material resin of the present invention.

Solid particles of the additive include pigments, fillers, aggregates, metal powders, magnetic powders, abrasives, and conductive powders such as carbon black as an antistatic agent. Examples of other additives include dyes, lubricants, dispersants and the like.

Any organic solvent may be used as long as it can dissolve the above block copolymer quickly.
One or a mixture of two or more solvents such as methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, toluene, ethyl acetate, tetrahydrofuran, dioxane and dimethylformamide is used.

[0036]

The coating material resin according to the present invention is
Since the polyacrylic component and the polyurethane component are bound together in a specific form and are composed of a copolymer containing a polar group in the molecule, a coating having a low viscosity and good coatability is used as a binder. The material can be easily prepared, and if the coating material contains solid particles such as pigments, fillers, aggregates, metal powders, magnetic powders, abrasives and conductive particles, the dispersibility of these particles will be good. Moreover, the coating film formed by this coating material has excellent mechanical properties, exhibits extremely high elasticity, and is tough, non-breakable, and has strong adhesion to the coated surface. Will be things.

The polyacrylic component of the above copolymer occupies the range of 10 to 50% by weight, and the number average molecular weight of the polyacrylic component is 1,000 to 10,000.
According to the constitution of 0, there is an advantage that the coating film made of the above-mentioned copolymer has particularly good mechanical properties.

Further, according to the method for producing a coating material resin according to the present invention, since one end-reactive acrylic polymer is reacted with both end-reactive urethane polymer, the diblock copolymer Polymers or triblock copolymers can be easily synthesized.

[0039]

EXAMPLES Next, examples of the present invention will be specifically described in comparison with comparative examples. The acrylic polymer with one end reactive and the urethane polymer with both ends reactive used in Examples and Comparative Examples were each manufactured by the following method. In the following, "parts" means "parts by weight".

<One-end Reactive Acrylic Polymer A1> Methyl Methacrylate 400 parts Mercaptoethanol 17 parts Azobisisobutyronitrile 4 parts Tetrahydrofuran 400 parts Three-necked flask equipped with a reflux condenser for the above composition. put in,
After sufficiently substituting with nitrogen, heating at 60 ° C. and reacting for 2.5 hours, the reaction solution was dropped into methanol to form a precipitate, which was filtered and dried under reduced pressure to obtain a molecule. A one-terminal-reactive acrylic polymer A1 having no polar group was obtained. The number average molecular weight of this polymer A1 measured by end group titration was 4,100.

<One-End Reactive Acrylic Polymer-A2> Methyl Methacrylate 390 parts Methacrylic acid 10 parts Mercaptoethanol 17 parts Azobisisobutyronitrile 4 parts Tetrahydrofuran 400 parts Other than using the above composition, In the same manner as in the case of the acrylic polymer A1, a one-end reactive acrylic polymer A2 having a carboxyl group in the molecule was obtained. This polymer A2 has a carboxyl group content of 0.2 by titration.
9 mmol / g, number average molecular weight by end group titration of 4,
It was 300.

<One-End Reactive Acrylic Polymer-A3> Methyl Methacrylate 376 parts 2-Acrylamido-2-methyl-1-propanesulfonic acid 24 parts Mercaptoethanol 17 parts Azobisisobutyronitrile 4 parts Tetrahydrofuran 400 Part A single-end reactive acrylic polymer A3 having a sulfonic acid group in the molecule was obtained in the same manner as in the case of the acrylic polymer A1 except that the above composition was used. This polymer
A3 has a sulfonic acid group content by titration of 0.27 mmol / g and a number average molecular weight by end group titration of 4,40.
It was 0.

<One-End Reactive Acrylic Polymer A4> Methyl Methacrylate 374 Parts 2-Methacryloxyethyl Acid Phosphate 26 Parts Mercaptoethanol 17 Parts Azobisisobutyronitrile 4 Parts Tetrahydrofuran 400 Parts Above A single-end-reactive acrylic polymer A4 having a phosphoric acid group in the molecule was obtained in the same manner as in the case of the acrylic polymer A1 except that the above composition was used. This polymer-A4
Had a number average molecular weight of 4,100 as determined by end group titration.

<One-End Reactive Acrylic Polymer-A5> Methyl Methacrylate 382 parts Dimethylaminoethyl Methacrylate 18 parts Mercaptoethanol 17 parts Azobisisobutyronitrile 4 parts Tetrahydrofuran 400 parts The above composition In the same manner as in the case of the acrylic polymer A1 except that it was used, a one-terminal-reactive acrylic polymer A5 having a tertiary amino group in the molecule was obtained. This polymer
A5 had a number average molecular weight of 4,300 as determined by end group titration.

<Urethane Polymer Reactive with Both Ends>B4> 4,4′-diphenylmethane diisocyanate 250 parts Polybutylene adipate (number average molecular weight 1,000) 500 parts 1,4-butanedio -Rule 40.5 parts Cyclohexanone / toluene (1/1) mixed solvent 3,160 parts Tin octylate 0.8 parts The above composition was placed in a three-necked flask equipped with a reflux condenser,
After sufficiently substituting with nitrogen, the mixture was heated to 100 ° C. and reacted for 5 hours to obtain a solution of urethane polymer B1 having both ends reactive with no polar group in the molecule. The number average molecular weight of this polymer B1 determined by end group titration was 16,300.

<Urethane Polymer Reactive with Both Terminals>B2> 4,4′-diphenylmethane diisocyanate 250 parts Polybutylene adipate (number average molecular weight 1,000) 500 parts 1,4-butanedio -Rule 29.9 parts 2.2-Dimethylpropionic acid 15.9 parts Cyclohexanone / toluene (1/1) mixed solvent 3,180 parts Tin octylate 0.8 parts The above composition was equipped with a reflux condenser. Put in a three-necked flask,
After sufficiently substituting with nitrogen, the mixture was heated to 100 ° C. and reacted for 5 hours to obtain a solution of urethane polymer B2 having a carboxyl group in the molecule and reactive at both ends. This polymer B2
Has a carboxyl group content of 0.15 mmol / g by titration and a number average molecular weight of 15,50 by end group titration.
It was 0.

Example 1 One end reactive acrylic polymer A2 86 parts Both end reactive urethane polymer B1 solution (163 parts resin content) 815 parts Cyclohexanone / toluene (1/1) mixed solvent 344 parts Tin octylate 0.25 parts into a three-necked flask equipped with a reflux condenser,
After sufficiently substituting with nitrogen, the mixture is heated to 100 ° C. and reacted for 8 hours to obtain a polyacrylic-polyurethane-polyacrylic triblock copolymer solution having a carboxyl group on the polyacrylic component side, which is used as a coating material. did. The completion of the above reaction was confirmed by the disappearance of the peak of the isocyanate group in the infrared absorption spectrum. This triblock copolymer had a carboxyl group content by titration of 0.098 mmol / g and a number average molecular weight by GPC measurement of 22,000 in terms of polystyrene.

Example 2 One end reactive acrylic polymer A1 82 parts Both end reactive urethane polymer B2 solution (resin content 155 parts) 775 parts Cyclohexanone / toluene (1/1) mixed solvent 328 parts tin octylate 0.25 part A polyacrylic-polyurethane-polyacrylic triblock copolymer solution having a carboxyl group on the polyurethane component side was obtained in the same manner as in Example 1 except that the above composition was used. It was used as a towing material. This triblock copolymer had a carboxyl group content by titration of 0.10 mmol / g and a number average molecular weight by GPC measurement of 21,000 in terms of polystyrene.

Example 3 One end reactive acrylic polymer-A2 86 parts Both end reactive urethane polymer-B2 solution (resin content 155 parts) 775 parts Cyclohexanone / toluene (1/1) mixed solvent 328 parts Tin octylate 0.25 parts Polyacryl-polyurethane-having a carboxyl group on both the polyacrylic component side and the polyurethane component side in the same manner as in Example 1 except that the above composition was used.
A polyacrylic triblock copolymer solution was obtained and used as a coating material. This triblock copolymer is
The content of carboxyl group by titration was 0.099 mmol / g, and the number average molecular weight by GPC measurement was 19,000 in terms of polystyrene.

Example 4 One end reactive acrylic polymer-A3 88 parts Both end reactive urethane polymer B1 solution (163 parts resin content) 815 parts Cyclohexanone / toluene (1/1) mixed solvent 352 parts Tin octylate 0.25 part A triacrylic copolymer solution of polyacrylic-polyurethane-polyacrylic having a sulfonic acid group on the polyacrylic component side was obtained in the same manner as in Example 1 except that the above composition was used. It was used as a coating material. This triblock copolymer had a sulfonic acid group content by titration of 0.092 mmol / g and a number average molecular weight by GPC measurement of 22,000 in terms of polystyrene.

Example 5 One end reactive acrylic polymer-A4 82 parts Both end reactive urethane polymer-B1 solution (163 parts resin content) 815 parts Cyclohexanone / toluene (1/1) mixed solvent 328 parts Tin octylate 0.25 parts A polyacrylic-polyurethane-polyacrylic triblock copolymer solution having a phosphoric acid group on the polyacrylic component side was obtained in the same manner as in Example 1 except that the above composition was used. It was used as a coating material. This triblock copolymer had a number average molecular weight measured by GPC of 21,000 in terms of polystyrene.

Example 6 One end reactive acrylic polymer-A5 86 parts Both end reactive urethane polymer-B1 solution (163 parts resin content) 815 parts Cyclohexanone / toluene (1/1) mixed solvent 344 parts Tin octylate 0.25 part A triblock copolymer solution of polyacrylic-polyurethane-polyacrylic having a tertiary amino group on the polyacrylic component side was obtained in the same manner as in Example 1 except that the above composition was used. Was used as the coating material. This triblock copolymer had a number average molecular weight, measured by GPC, of 22,000 in terms of polystyrene.

Comparative Example 1 One end reactive acrylic polymer A1 82 parts Both end reactive urethane polymer B1 solution (163 parts resin content) 815 parts Cyclohexanone / toluene (1/1) mixed solvent 328 parts Tin octylate 0.25 parts In the same manner as in Example 1 except that the above composition was used, a polyacrylic-polyurethane-polyacrylic triblock copolymer solution having no polar group in the molecule was obtained.
This was used as a coating material. The number average molecular weight of this triblock copolymer measured by GPC was 21,000 in terms of polystyrene.

Comparative Example 2 4.4'-diphenylmethane diisocyanate 250 parts Polybutylene adipate (number average molecular weight 1,000) 500 parts 1.4-butanediol 37.8 parts 2. 2-Dimethylolpropionic acid 10.7 parts Cyclohexanone / toluene (1/1) mixed solvent 3,190 parts Tin octylate 0.8 parts The above composition was placed in a three-necked flask equipped with a reflux condenser,
After sufficiently substituting with nitrogen, the mixture was heated to 100 ° C. and reacted for 5 hours to obtain a polyurethane resin solution having a carboxyl group in the molecule, which was used as a coating material. This polyurethane resin had a carboxyl group content by titration of 0.10 mmol / g and a number average molecular weight by GPC measurement of 24,000.

Comparative Example 3 4'-Diphenylmethane diisocyanate 500 parts Polybutylene adipate (number average molecular weight 1,000) 500 parts 1.4-Butanediol 80.2 parts 2. 2-Dimethylolpropionic acid 14.7 parts Cyclohexanone / toluene (1/1) mixed solvent 3,190 parts Tin octylate 0.8 parts The above composition was placed in a three-necked flask equipped with a reflux condenser,
After sufficiently substituting with nitrogen, the mixture was heated to 100 ° C. and reacted for 5 hours to obtain a polyurethane resin solution having a carboxyl group in the molecule, which was used as a coating material. This polyurethane resin had a carboxyl group content by titration of 0.10 mmol / g and a number average molecular weight by GPC measurement of 22,000.

The coating materials of the above Examples and Comparative Examples were tested for mechanical properties of the coating film, adhesion to the surface to be coated, and dispersibility of solid particles by the following methods. The results are shown in Table 1 below.

<Mechanical properties> Each coating material has a gap 2
It was coated on a release paper with a 00 μm applicator, dried at room temperature for 24 hours, and then dried by heating at 60 ° C. for 72 hours, and then the coating film was peeled off from the release paper to obtain a sample film. This sample film was cut into a width of 5 mm, and Young's modulus, breaking strength and breaking elongation were measured by a tensile tester. The coating material of Comparative Example 3 had a high viscosity and required a special operation such as application in a heated state.

<Adhesiveness> Each coating material has a gap of 200
Apply on polyethylene terephthalate film with μm applicator, dry at room temperature for 24 hours, then 6
A coating film was prepared by heating and drying at 0 ° C. for 72 hours. Cellophane tape was attached to the coating film surface of this coating film, and this tape was rapidly peeled off to examine the degree of peeling of the coating film. The results were evaluated on a three-point scale, in which the coating film which was not peeled at all was evaluated as ◯, the film which was slightly peeled was evaluated as Δ, and the film which was widely peeled was evaluated as x.

<Dispersibility> γ was added to 200 parts of each coating material.
-Fe ₂ O ₃ powder (average major axis diameter 0.4 μm, average axial ratio 1: 9) 160 parts and cyclohexanone / toluene (1 /
1) Add 400 parts of the mixed solvent and mix and disperse in a ball mill for 96 hours to prepare a magnetic coating, which has a gap of 60 μm.
Was coated on a polyethylene terephthalate film with the above application and dried with warm air to prepare a magnetic film. Observe this film with the naked eye and electron microscope,
O: When the gloss was observed and the powder particles were found to be uniformly dispersed under an electron microscope, ○; When the gloss was slightly low or when the powder was found to be slightly uneven under the electron microscope, Δ: Without a gloss, under an electron microscope The one in which many lumps of powder particles were recognized was evaluated in three levels of x.

[0060]

[Table 1]

From the results in the above table, the coating material resins (Examples 1 to 6) of the present invention, which are composed of a block copolymer of a polyacrylic component and a polyurethane component and contain a polar group in the molecule, are obtained. For example, a coating film having excellent mechanical properties can be formed, and the conventional general polar group-containing polyurethane resin (Comparative Example 2) can be used in terms of the adhesiveness of the coating film to the surface to be coated and the dispersibility of solid particles. It is clear that the same performance as the case of using () is exhibited.

On the other hand, in the conventional polar group-containing polyurethane resin (Comparative Example 3) in which the ratio of the hard component in the polymer was increased, the elastic modulus of the coating film was slightly improved, but the coating composition of the present invention was used. It can be seen that it is significantly inferior to the resin for the towing material, and the above-mentioned adhesiveness and dispersibility are deteriorated. Further, a coating material resin made of the same block copolymer but having no polar group in the molecule (Comparative Example 1) has good mechanical properties, but remarkably shows the above-mentioned adhesiveness and dispersibility. It turns out to be inferior.

Front Page Continuation (72) Inventor Kazushi Miyata 1-88, Torora, Ibaraki City, Osaka Prefecture Hitachi Maxell Co., Ltd.

Claims (4)

[Claims] 1. A coating material resin comprising a polyacrylic-polyurethane diblock copolymer or a polyacrylic-polyurethane-polyacrylic triblock copolymer, and containing a polar group in the molecule. .. 2. The polyacrylic component of the copolymer is 10 to 5
The coating material resin according to claim 1, which occupies a range of 0% by weight. 3. The coating material resin according to claim 1, wherein the polyacrylic component of the copolymer has a number average molecular weight of 1,000 to 10,000. 4. The diblock copolymer or triblock copolymer according to claim 1, which is obtained by reacting a one-terminal-reactive acrylic polymer with a both-terminal-reactive urethane polymer. A method for producing a coating material resin, which comprises synthesizing