JPH04178418A - Polyurethane resin and its production, use and usage - Google Patents

Abstract

PURPOSE:To obtain the subject aqueous resin, capable of exhibiting adhesion to various films and providing aqueous coating agents excellent in laminating suitability by using a polyester diol, containing a specific amount of an aromatic dicarboxylic acid component. CONSTITUTION:The objective resin is obtained by initially reacting (A) an organic diisocyanate with (B) a polyester diol, prepared from (i) a dicarboxylic acid containing >=25mol% aromatic dicarboxylic acid and (ii) a diol with side chain and having 800-3000 molecular weight, providing a prepolymer having terminal NCO, then adding a water-miscible solvent thereto, subsequently reacting (C) a polyfunctional chain extender having >=3 active hydrogens and (D) a carboxyl group-containing compound for solubilizing the polyurethane resin in water therewith and further adding water and ammonia to the prepared product. The aforementioned resin has 30-100 acid value.

Description

Detailed Description of the Invention <Field of Industrial Application> The present invention relates to a polyurethane resin useful as a binder resin for coating materials such as water-based printing inks or coating agents. The object of the present invention is to provide a polyurethane resin having excellent adhesion to and suitability for post-processing such as suitability for lamination.

<Conventional technology> In recent years, with the diversification of packaging containers and the increasing functionality of synthetic resin products such as synthetic leather, coating materials used for decoration and surface protection of plastic films, especially those coated on the surface of the film, have become more and more popular. Various coating agents are required to have sufficient adhesion to adherends, strong durability, and suitability for post-processing.

For example, in printing ink for plastic film,
They are required to have adhesion to various films, excellent printability, various durability, and furthermore, suitability for lamination processing, which gives these printed materials high added value. There are two main methods for this laminating process.
One is an extrusion lamination method in which ink is printed on a film and then a molten polymer is laminated via an anchor coating agent, and the other is a dry lamination method in which the film is laminated via an adhesive.

From the above background, as printing inks for conventional plastic films, depending on the performance required,
Organic soluble inks made of binders such as polyurethane resin, rosin/maleic acid resin, acrylic resin, and polyamide resin were used.

However, recently, from the viewpoints of environmental issues, resource conservation, labor safety, and fire safety, there has been a strong demand for water-based printing inks that minimize the use of organic abrasions.

In printing on paper, etc., many printing inks have shifted to water-based types from an early stage, but in printing on plastic films, etc., some water-based inks with binder resins such as water-based acrylic resin are used. It is just something that has been put into practical use.

Further, in this case, the applicable films are limited to polyolefins, and the suitability for lamination is not sufficient.

Therefore, water-soluble or water-dispersed polyurethane resins that have excellent adhesion and lamination suitability for various films and form flexible and tough films are being considered, but it is possible to obtain high-performance water-based polyurethane resins. The current situation is that things are extremely difficult.

Generally, an aqueous polyurethane resin is obtained by reacting an organic diisocyanate compound, a polyester type or polyether type polymeric diol, a chain extender if necessary, and a carboxyl group-containing compound. and,
In order to obtain more stable aqueous polyurethane resins, highly hydrophilic aliphatic polyester diols or polyether diols have been used among polymeric diol components for boat fishing.

However, when a water-based ink using a water-based polyurethane resin made of these components as a binder is used, there are problems such as insufficient adhesion to a polyester (PET) film.

On the other hand, a polyurethane resin using an aromatic polyester polyol as a diol component has been proposed, for example, in JP-A-61-228030.
It has been reported that the adhesion to ET film is improved.

However, when a polyester diol prepared by reacting an aromatic dicarboxylic acid with a general glycol is used, the resulting polyurethane resin forms a hard film with high crystallinity. Even if this resin film adheres to the film alone, if the printing ink contains 30% or more of hard particles such as pigments in the film, it will become an even harder film, resulting in loss of flexibility and resistance to rubbing and scratching. This method has the disadvantage that satisfactory ink performance cannot be obtained due to a decrease in properties and the like.

On the other hand, when looking at suitability for lamination processing, there are also the following problems.

Post-processing such as lamination is usually performed separately from the printing process, so even if the printing ink used for printing has become water-based due to various problems, the anchor coating agent or It is anticipated that conventional solvent-based adhesives may be used. Of course, as printing inks become increasingly water-based, it is expected that these will also become water-based.

In this way, when a conventional solvent-based anchor coating agent or adhesive is used, if a polyester diol that does not contain a specific amount of aromatic dicarboxylic acid component is used as the polymer diol, the solvent-based anchor coating agent or adhesive There are problems such as the wettability of the adhesive becomes extremely poor and good lamination suitability cannot be obtained. Therefore, as a polyurethane resin that is a binder for water-based inks, it is necessary that the anchor coating agent or adhesive used for lamination is applicable to both water-based and solvent-based types.

<Problems to be Solved by the Invention> The present invention aims to solve the above-mentioned problems in water-based coating agents or coating agents such as printing inks, and is intended to solve the above-mentioned problems with coating agents such as water-based coating agents or printing inks, and which exhibits adhesion to various films and has excellent lamination suitability. It is an object of the present invention to provide a polyurethane resin that provides an aqueous coating.

<Means for Solving the Problem> That is, the present invention provides a polyurethane resin comprising an organic diisocyanate compound, a polymeric diol compound, a chain extender, and a carboxyl group-containing compound for water solubilization, wherein the diol compound has a molecular weight of 800 to 800. 3,000 and a dicarboxylic acid containing 25 mol% or more of aromatic dicarboxylic acid and a glycol having a side chain, the chain extender is a polyfunctional chain extender having three or more active hydrogens, and It is an object of the present invention to provide a polyurethane resin characterized in that the acid value of the polyurethane resin is in the range of 30 to 100.

Hereinafter, the polyurethane resin according to the present invention will be explained in more detail.

First, the organic diisocyanate component used in this polyurethane resin includes alicyclic diisocyanate compounds such as isophorodiisocyanate, hydrogenated xylylene diisocyanate, 4゜4-dicyclohexylmethane diisocyanate, and aliphatic diisocyanate compounds such as tetramethylene diisocyanate and hexamethylene diisocyanate. Examples include diisocyanate compounds, aromatic aliphatic diisocyanate compounds such as xylylene diisocyanate and tetramethylxylylene diisocyanate, and aromatic diisocyanate compounds such as toluene diisocyanate and diphenylmethane diisocyanate. In addition, from the viewpoint of not increasing the crystallinity of the resin too much, in the organic diisocyanate component, aliphatic,
Aliphatic or aromatic aliphatic compounds are preferred.

In addition, in the acid component for obtaining a polymer diol compound, aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6- Examples include aromatic dicarboxylic acids such as naphthalene dicarboxylic acid, naphthalic acid, and biphenyl dicarboxylic acid, and their anhydrides or ester-forming derivatives.

On the other hand, examples of aliphatic or alicyclic dicarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, 1,3-cyclopentanedicarboxylic acid,
Examples include 1,4-cyclohexanedicarboxylic acid and their anhydrides.

In addition, as the glycol component to be reacted with the above acid component, side chains such as propylene glycol, dipropylene glycol, neopentyl glycol, 3-methyl-1,5-bentanediol, 2-ethyl-1°3-hexylene glycol, etc. Examples include glycols having the following.

On the other hand, when a linear glycol component (BO1) ester diol is used, the resulting polyurethane resin forms a hard film with high crystallinity compared to the above-mentioned side chain glycol component.

Furthermore, if a polyfunctional polyol is used during the synthesis of the prepolymer, the crosslinking density will become too high, causing gelation.

In order to obtain a polyester diol from the acid component and glycol component exemplified above, it is necessary that the acid component contains at least 25 mol% or more of aromatic dicarboxylic acid. If the aromatic dicarboxylic acid content is less than 25 mol%, the adhesion to films such as PET will be significantly reduced, and in terms of suitability for post-processing, wetting with solvent-based anchor coating agents or adhesives will be poor, resulting in poor lamination processing. I can't get the aptitude.

The polyester diol of the present invention is not limited to a copolymerized polyester diol containing 25 mol% or more of aromatic dicarboxylic acid, but may also be a copolymerized polyester diol containing 25 mol% or more of aromatic dicarboxylic acid; It may be a mixture.

Further, the molecular weight of the polyester diol is 800 to
3000, preferably in the range of 1000 to 2000. If the molecular weight is less than 800, the synthesized polyurethane resin will have excessive cohesive force between the resins, resulting in poor adhesiveness and lamination suitability. on the other hand,
If the molecular weight exceeds 3000, on the contrary, the cohesive force between the resins will be insufficient and blocking will easily occur. Furthermore, it becomes difficult to increase the concentration of pendant carboxyl groups introduced for making the composition aqueous, and accordingly, it becomes difficult to maintain a stable dissolution state in an aqueous system.

In addition, the carboxyl group-containing compound necessary to make this polyurethane resin water-based is a compound having a pendant carboxyl group and represented by the general formula %. can be reacted in the chain extension step. In addition, if #sake is lower than 30, it will be difficult for the obtained polyurethane resin to maintain a stable dissolution state in an aqueous system, and if it exceeds 100, it will be difficult for the obtained polyurethane resin to maintain a stable dissolution state in an aqueous system. However, the resin film obtained is hard with low water resistance, and good physical properties of the film cannot be obtained.

In addition, as chain extenders used in the present invention, aliphatic polyols such as glycerin, 1,2,3-trimethylolpropane, and pentaerythritol,
．． Examples include alicyclic polyols such as 3.5-cyclohexanetriol and aliphatic polyamines such as diethylenetriamine and triethylenetetramine, but polyol-based chain extenders are preferred.

If a linear chain extender is used for polymerization, it becomes difficult to obtain a high molecular weight polyurethane resin that is stable in an aqueous system.

When producing water-based polyurethane resin, organic diisocyanate and high molecular weight polyester diol are reacted,
Synthesizing a prepolymer having an NC○ group at the end, reacting it with a polyhydroxycarboxylic acid and a chain extender,
Furthermore, the pendant carboxyl group within the molecule can be neutralized with ammonia or an organic amine to make it aqueous.

In addition, water-miscible solvents that do not react with diisocyanate compounds during chain extension, are soluble in water, and can dissolve the above-mentioned polyurethane resin components well, such as 1-methyl-2-
By using pyrrolidone, acetone, etc. as a co-solvent, a high molecular weight and uniform polyurethane resin can be synthesized.

The molecular weight of the polyurethane resin obtained in this way is 20
000 to 200,000, more preferably 100,000 to
It is 120,000. If the molecular weight is less than 20,000, the ink film will be inflexible and brittle;
If it exceeds 00,000, the viscosity of the aqueous polyurethane resin solution increases and it becomes difficult to make it aqueous.

Examples of bases that neutralize pendant carboxyl groups in order to make polyurethane resin water-based include ammonia, triethylamine, monoethanolamine, triethanolamine, and N-methylmorpholine, but they do not affect the water resistance of the resin film after drying. When using the water-based polyurethane resin specified in the present invention synthesized from 6 or more components as a binder for printing ink or coating agent, it is preferable to use one that easily dissociates and volatilizes at room temperature or slight heating in order to increase the For the aqueous polyurethane resin solution, add various pigments as coloring agents, if necessary,
Anti-blocking agents, anti-foaming agents, cross-linking agents and other additives,
In addition, as a solvent that mixes with various other aqueous resins, such as cellulose, maleic acid resin, acrylic resin, and even water,
Water-based printing inks and coating agents can be produced by adding, dispersing, and mixing methanol, ethanol, isopropertool, methoxypropertool, etc.

The aqueous printing ink or coating agent thus obtained solves the problems of conventional aqueous polyurethane resins and has various properties such as film performance and suitability for post-processing.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In addition, parts in Examples indicate parts by weight.

<Example> 11 Colors-1 In a four-necked flask equipped with a stirrer, thermometer, Dimroth, and N2 gas inlet tube, isophthalic acid/adipic acid (molar ratio 50150) and 3-methyl-1°5-bentanediol were added. 300 parts of the obtained polyester diol with an average molecular weight of 1000 and inphorone diisocyanate)
146.5 parts, and while introducing N2 gas, 90
The reaction was carried out at ~95°C for 4 hours, and after the reaction, 1-methyl-2
- 118 parts of pyrrolidone, 11 parts of trimethylolpropane.
6 parts of dimethylol 10 bio7 rim were added, and the reaction was carried out at 140-150°C until the NCO group disappeared. After the reaction is completed, the mixture is cooled to 100°C, and 1059 parts of water and 349 parts of triethylamine are added to make it water-solubilized. The resulting resin had a solid content of 30% and a viscosity of 4.5 voids/25°.
C, M bond 38 aqueous polyurethane resin solution (resin solution A
)Met.

E11 An aqueous polyurethane resin solution (resin solution B) was produced using the following charging composition in the same manner as in Example-1.

Inphorone diisocyanate 146°5 parts Dimethylpropionic acid 46.3 parts Trimethylolpropane 11.6 parts Water
1059
part triethylamine 349 parts l-
118 parts of methyl-2-pyrrolidone The obtained resin was an aqueous polyurethane resin solution having a solid content of 30% by weight, 4.2 voids/25°C, and an acid value of 38.

Fire 11 Toni Σ An aqueous polyurethane resin solution (resin solution C) was produced using the following charging composition in the same manner as in Example-1.

Inphorone diisocyanate 146.5 parts Dimethylpropionic acid 46.3 parts Trimethylolpropane 11.6 parts Water
1059 parts Triethylamine 34.9 parts 1-methyl-2-pyrrolidone 118 parts The obtained resin had a solid content of 30% by weight, 4.6 voids/25°C, and an acid value of 3.
It was an aqueous polyurethane resin solution of No. 8.

Ruji JL2F An aqueous polyurethane resin solution (resin solution D) was produced using the following charging composition in the same manner as in Example-1.

Polycaprolactone diol (molecular weight 1200) 300 parts Isoisophorone diisocyanate 122.1 parts Dimethylolpropionic acid 38.6 parts Trimethylolpropane 9.7 parts Water
988 parts Triethylamine 29.1 parts N-methylpyrrolidone 110 parts The obtained resin was an aqueous polyurethane resin solution having a solid content of 30%, a viscosity of 4.1 voids/25°C, and an acid value of 38.

An aqueous polyurethane resin solution (resin solution E) was produced using the following charging composition in the same manner as in Example-1.

Poly-3-methylbenzene adipate (molecular weight 100
0) 300 parts Inphorone diisocyanate 146.5 parts Dimethylpropion #46.3 parts Trimethylolpropane 11.6 parts Water
1059
part triethylamine 34.9 parts l-
118 parts of methyl-2-pyrrolidone The obtained resin was an aqueous polyurethane resin solution having a solid content of 30%, a viscosity of 4.1 voids/25° C., and an acid value of 38.

salt! An aqueous polyurethane resin solution (resin solution F) was produced using the following charging composition in the same manner as in 1L- and Example-1.

Poly-3-methylpentylene adipate (molecular weight 100
0) 210 parts Isophorone diisocyanate 146.5 parts Dimethylpropionic acid 46.3 parts Trimethylolpropane
11.6 parts water
1059 parts triethylamine
34.9 parts l-methyl-2-pyrrolidone 118 parts The resulting resin had a solid content of 30%,
It was an aqueous polyurethane resin solution with a viscosity of 4.3 voids/25°C and an acid value of 38.

An aqueous polyurethane resin solution was produced using the following charging composition in the same manner as in Example-1.

Polycar 3-methylbenzene phthalate (molecular weight 1000) 300 parts Isoisophorone diisocyanate 146.5 parts Dimethylolpropion 112 23.2 parts Trimethylolpropane 30.6 parts Water
1059 parts Triethylamine 17.5 parts N-methylpyrrolidone 118 parts The obtained resin was an aqueous polyurethane resin solution with a solid content of 30%, a viscosity of 2.1 voids/25°C, and an acid value of 19, but it separated and settled over time. , it lacked stability. Therefore, it was excluded from the evaluation.

119-1 An aqueous polyurethane resin solution (resin solution G) was produced using the following charging composition in the same manner as in Example-1.

Polycarbonate 3-methylbenzene terephthalate (molecule 1
1000) 300 parts Isoisophorone diisocyanate 146.5 parts Dimethylolpropionic acid 46.3 parts Ethylene glycol 8.0 parts Water
1059 parts Triethylamine 17.5 parts N-methylpyrrolidone 118 parts The obtained resin was an aqueous polyurethane resin solution having a solid content of 30% and a viscosity of 4.6 voids/25° C. and an acid value of 38.

LfLisu1 Each of the resin solutions A to G obtained in Examples 1 to 3, Comparative Examples 1 to 3, and 5 was used as a binder for printing ink, and the performance of each resin was evaluated. Each printing ink is manufactured by mixing and kneading the following composition.

Resin solution 46.7 parts Cyanine blue 14.0 parts Water
39.3 copies of each printing ink were used to print on various films, and the adhesion and lamination suitability were evaluated. The results are shown in Table 1.

In addition, each evaluation method was performed by the following method.

1) Regarding color development, transparency, and density of pigment-dispersed printed matter, compared to commercially available solvent-based back printing inks, those that are superior are ◎, those that are equivalent are O1, those that are inferior are △, and those that are not suitable was evaluated as ×.

2) Adhesiveness When each ink was printed on a designated film using a gravure proofing machine and left for one day, sellotape was applied to the printed surface and this was rapidly peeled off, the printed film did not come off at all. Those with 80% or more remaining on the film were indicated as (◎), those with 50% to 80% remaining on the film (△), and those with only 20% or less remaining on the film were indicated as (x).

3) Extrusion lamination suitability For printed matter of each ink, imine-based and isocyanic anchor coating agents are used on OPP and PET films, molten polyethylene is laminated using an extrusion laminator, and after 3 days, the sample is cut into a 30IIlffi width. T-peel strength (Durham) was measured using a peel test manufactured by Yasuda Seiki Co., Ltd.

4) Dry lamination strength For each ink print, a solvent-based and water-dispersible urethane adhesive is used, and a dry lamination machine is used to
The P film was laminated, and the peel strength was measured in the same manner as in the measurement of the 3-day push-out laminate strength.

<Effects> As shown in the examples above, water-based inks using the water-based polyurethane resin according to the present invention C2 (in this case, various films (2) have a wide range of adhesion properties and a sinker agent). Alternatively, it can be seen that even the adhesive i1P+hydrohydric type and the container type 1 have excellent laminate strength.

Claims (1)

[Scope of Claims] 1) A polyurethane resin obtained by reacting an organic diisocyanate compound, a polymeric diol compound, a chain extender, and a carboxyl group-containing compound for water solubilization, wherein the polymeric diol compound is an aromatic dicarbonate. Molecular weight 800-3000 obtained from a dicarboxylic acid containing at least 25 mol% of acid and a glycol having a side chain
a polyester diol in the range of, the chain extender is a polyfunctional chain extender having three or more active hydrogens, and the acid value of the resin is in the range of 30 to 100. resin. 2) The polyurethane resin according to claim 1, wherein the glycol is 3-methyl-1,5-pentanediol. 3) The polyurethane resin according to claim 1, wherein the polyfunctional chain extender has three or more hydroxy groups. 4) The carboxyl group-containing compound has the general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (However, R in the formula represents a hydrogen atom or a linear or side chain alkyl group having 1 to 8 carbon atoms. ) The polyurethane resin according to claim 1, which is a compound represented by: 5) After reacting an organic diisocyanate compound, a dicarboxylic acid containing 25 mol% or more of an aromatic dicarboxylic acid, and a polyester diol obtained from a glycol having a side chain to obtain a prepolymer having terminal isocyanate groups, a water-miscible solvent is used. , reacting a polyfunctional chain extender having three or more active hydrogens and a carboxyl group-containing compound for water-based conversion, and further adding water and ammonia or an organic amine. Method 6) An aqueous coating material containing a colorant, the aqueous polyurethane resin according to claim 5, and water as main components. 7) A laminating method comprising further coating an anchor coating agent or an adhesive on the plastic film coated with the aqueous coating agent according to claim 6, and laminating a melted or film-like polymer thereon.