JPS598364B2 - Method for manufacturing polyurethane solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyurethane solution in an organic solvent. The present invention relates to a method of manufacturing, in particular a solution of polyurethane in an organic solvent suitable as a printing ink vehicle.

Polyurethane solutions have traditionally been used as printing ink vehicles, but they sometimes have insufficient adhesion to plastic films such as polyethylene, polypropylene, polyester, and nylon, or only have good adhesion to certain films. Print surface strength, non-adhesiveness,
Many had poor performance such as water resistance, oil resistance, acid resistance, and alkali resistance.

Furthermore, depending on the purpose of the printed matter, a two-component polyurethane solution is sometimes used as the printing ink vehicle because higher durability is required. This resulted in complicated management, which was disadvantageous from an industrial standpoint. As a result of intensive research to solve these problems, the inventors of the present invention have found that even as a one-component type,
The present invention has been completed by discovering a method for producing an organic solvent solution of polyurethane suitable for use as a two-component printing ink vehicle.

That is, the present invention provides a method for producing an organic solvent solution of polyurethane from a polyhydroxy compound, an organic polyisocyanate, a chain extender, a polymerization terminator, and an organic solvent. It represents an alkylene group, and R2 and R3 represent H1 hydroxyethyl group and hydroxypropyl group.

However, at least one of R2 and R3 is not H.

), and a chain extender represented by the general formula (B) (R4, R
5 represents a hydroxyethyl group or a hydroxypropyl group.

) A method for producing an organic solvent solution of polyurethane having a molecular weight of 5,000 to 100,000 and having at least two urea bonds and at least two hydroxyl groups in one molecule, the method comprising using a polymerization terminator represented by This is what we provide.

Since the polyurethane obtained in the present invention has two or more urea bonds and hydroxyl groups, it has excellent adhesion to plastic films such as polyethylene, polypropylene, polyester, and nylon, and has a sufficient molecular weight. Lower alcohols, ethyl acetate, and toluene are commonly used in printing inks because they have excellent properties such as surface strength, non-adhesiveness, water resistance, oil resistance, acid resistance, and alkali resistance, and also contain hydroxyl groups. In addition to being diluted with solvents such as polyisocyanate curing agents, when used as a so-called two-component ink vehicle, the hydroxyl groups participate in the crosslinking reaction to obtain printed materials with excellent durability. I can do it. That is, the major feature of the polyurethane organic solvent solution of the present invention is that it has excellent physical properties as a printing ink vehicle and can be used as a one-component or two-component solution.

The polyhydroxy compound used in the present invention is an oligomer.
Including polyols and monomeric polyols, oligomer polyols include polyether polyols such as polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, etc., ethylene glycol, propylene glycol, 1,3-butanediol, 1・4-butanediol, neopentyl glycol, pentanediol, hexanediol, octanediol, 1,4-butynediol, 2-ethyl-1,3-hexanediol,
Bisphenol A1 For ring-opening polymerization of polyester polyols and cyclic ester compounds obtained by dehydration condensation reaction from saturated and unsaturated low-molecular-weight glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol and dibasic acids. In addition to the polyester polyols, polyester amides, polyacetals, polythioethers, polybutadiene glycols, etc. that are obtained, there are also glycols that are obtained by adding ethylene oxide and propylene oxide to bisphenol A, which are generally used in the production of polyurethane. Known polyols can be used, and their molecular weights generally range from 200 to 3,000.

On the other hand, representative examples of monomeric polyols include low molecular weight glycols and glycerin, which are used as raw materials for the above-mentioned polyester polyols. is preferred. The organic polyisocyanates used in the present invention include aromatic, aliphatic, and alicyclic polyisocyanates, such as 1,5-naphthylene diisocyanate,
4.4/-diphenylmethane diisocyanate, 4.4
'-Diphenyldimethylmethane diisocyanate, di- and tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzylisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, toluene diisocyanate, butane- 1・4
-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, hexane-1,6 diisocyanate, lysine diisocyanate, cyclohexane-1
・4-diisocyanate, xylene diisocyanate,
Isoborone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1-methylbenzole-2,4,6-triisocyanate, methylcyclohexylene diisocyanate, biphenyl-2,4,4'-triisocyanate, isopropylidene dicyclohexyl-4, Representative examples include 4'-diisocyanate and triphenylmethane triisocyanate.

The chain extender represented by the general formula (A) used in the present invention is an ethylene oxide or propylene oxide adduct of C2 to C6 lower alkylene diamines such as ethylene diamine, propylene diamine, butylene diamine, and hexamethylene diamine. , 2-hydroxyethylethylenediamine, di-2-hydroxyethylethylenediamine, 2-
Hydroxyethylpropylene diamine, di-2-hydroxyethylpropylene diamine, 2-hydroxyethylbutylene diamine, di-2-hydroxyethylbutylene diamine, 2-hydroxyethylhexamethylene diamine, di-2-hydroxyethylhexamethylene diamine, 2- Hydroxypropylethylenediamine, di-2-
Hydroxypropylethylenediamine, 2-hydroxypropylpropylenediamine, di-2-hydroxypropylpropylenediamine, 2-hydroxypropylbutylenediamine, di-2-hydroxypropylbutylenediamine, 2-hydroxypropylhexamethylenediamine, di-2-hydroxypropyl Hexamethylene diamine and the like are preferred.

Examples of the polymerization terminator represented by the general formula (B) used in the present invention include diethanolamine, isopropanolamine, and diisopropanolamine.

In producing the organic solvent solution of polyurethane of the present invention, it is necessary to introduce at least two urea bonds and at least two hydroxyl groups into the polyurethane molecule, and for this purpose, the above general formula ( It is necessary to use both the chain extender represented by A) and the polymerization terminator represented by general formula (B) in combination in order to significantly exhibit the features of the polyurethane of the present invention.

The solvent used in the production of the organic solvent solution of polyurethane of the present invention is preferably a solvent commonly used in printing inks, such as ethyl acetate, acetone, toluene, methyl ethyl ketone, tertiary butanol, ethanol, isopropanol, cyclohexanone, dioxane. , tetrahydrofuran, trichrene, perchrene, chlorobenzene, etc. are representative examples.

Although polyurethane can be produced without a solvent and dissolved in a solvent after polymerization, it is advantageous to carry out the polymerization in the presence of a solvent in order to obtain a uniform polymer solution.

Regarding the production method of polyurethane, there is a two-step method in which a urethane prepolymer or urethane polymer having free isocyanate groups is obtained from a polyhydroxy compound and an organic polyisocyanate, and then reacted with a chain extender and a polymerization terminator, and Any one-step method in which the hydroxy compound, organic polyisocyanate, chain extender, and polymerization terminator are reacted at once may be used, but the former method is preferred for the purpose of obtaining a uniform polymer solution.

The chain extender used in the present invention is represented by the general formula (A), but the combined use of known polyols and polyamines commonly used in the production of polyurethane means that at least two It is permissible if it can contain a urea bond and at least two hydroxyl groups.

When producing the organic solvent solution of the polyurethane of the present invention by a two-step process, it is necessary that the free isocyanate groups bonded to the urethane prepolymer or urethane polymer be equivalent to the amino groups of the chain extender and polymerization terminator. is important.

When the isocyanate group is in excess, the isocyanate group also reacts with the hydroxyl groups of the chain extender and the polymerization terminator, resulting in high solution viscosity, and at least two groups in one molecule, which are important in the structure of the present invention, may react with each other. It may become impossible to obtain polyurethane having hydroxyl groups. On the other hand, if there is an excess of amino groups, the chain extender and polymerization terminator remain unreacted, which can cause problems such as odor, gloss, and
This will have an adverse effect on adhesive properties, etc. Therefore, the hydroxyl groups in the chain extender represented by general formula (A) and the polymerization terminator represented by general formula (B) are used in the production of polyurethane.
It is important to control it so that it does not react with isocyanate groups. The molecular weight of the polyurethane of the present invention is preferably 5,000 to 100,000, and when it is less than 5,000, when it is used as a printing ink vehicle, the surface strength, non-adhesiveness, water resistance, oil resistance, etc. of the printed matter will deteriorate. On the other hand, if it is greater than 100,000, the viscosity of the polyurethane organic solvent solution is high, making it difficult to handle as a printing ink vehicle, and causing cloudiness when diluted with organic solvents commonly used in printing inks. , the viscosity may increase, more preferably 5000 to 50
000 is appropriate.

The resin content concentration of the polyurethane organic solvent solution of the present invention is not particularly limited, but is preferably 15% to 60%, and the viscosity is practically preferably 100 cps to 100,000 eps (25°C).

The organic solvent solution of polyurethane produced as described above is diluted with a solvent commonly used in printing inks as needed, and mixed with a pigment using a kneading machine such as a ball mill. The printing ink used is polyethylene,
It exhibits excellent adhesion to films such as polypropylene, polyester, and nylon, and improves the surface strength, non-adhesiveness, and
It has excellent properties such as water resistance, oil resistance, acid resistance, alkali resistance, etc. Furthermore, when used in combination with a polyisocyanate hardener, it exhibits excellent durability such as poll resistance.

As the polyisocyanate curing agent used in two-component inks, the aforementioned organic polyisocyanates can also be used, but due to handling advantages such as toxicity and pot life, low molecular weight polyols and excessive amounts of organic polyisocyanates are preferred. Preferred examples include polyisocyanates having free isocyanate groups obtained from polyisocyanates, such as triisocyanates synthesized from 1 mole of trimethylolpropane and 3 moles of tolylene diisocyanate or 1,6-hexamethylene diisocyanate. .

In addition, the one-component or two-component printing ink has excellent printability and printing effect in gravure printing, and is glossy, odorless, and has excellent drying properties. Aptitude) is also good. In the production of printing ink, the organic solvent solution of the polyurethane of the present invention can be mixed with a polymer such as nitrocellulose, polyvinyl chloride, polyamide, (meth)acrylic acid ester polymer, etc., if necessary.

Furthermore, in addition to its use as a printing ink vehicle, the polyurethane solution of the present invention in an organic solvent can be used for textile materials, paper, leather,
It can be impregnated into rubber, wood, metal, concrete, plaster, glass, glass fiber, plastics, etc., or applied to these surfaces to improve performance such as surface modification, adhesion, and texture improvement. It is also useful as a binder, adhesive, etc. for civil engineering and construction, various ceramic industries, etc.

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, but it goes without saying that the present invention is not limited thereto.

In addition, all parts and percentages in the examples are based on weight unless otherwise specified. Example 1 1508 parts of polyoxytetramethylene glycol with a molecular weight of 2011 dehydrated and dried under reduced pressure at 90°C for 2 hours and 1.
338 parts of 4-butanediol and 1 part of methyl ethyl ketone
Put 844 parts into a round bottom flask equipped with a stirrer and a thermometer, and after dissolving it uniformly, mix 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate in an 80:20 ratio under water cooling (22°C). When 921 parts of the mixture (hereinafter simply referred to as "tolylene diisocyanate") was added, the temperature rose to 55° C. in 5 minutes.

Next, the reaction was continued at 75° C. for 5 hours to obtain a urethane prepolymer solution (resin concentration: 60%) containing 1.38% of free isocyanate groups. 2 in another round bottom flask
- Add 16.5 parts of hydroxypropyl ethylene diamine, 4.66 parts of diisopropanolamine and 969 parts of methyl ethyl ketone, mix uniformly, and then add 920 parts of the above urethane prepolymer solution at 22°C to 27°C for 40 minutes. The polyurethane solution was added dropwise and reacted at 50°C for 30 minutes to obtain a homogeneous and transparent polyurethane solution with a concentration of 30% and a viscosity of 1086 cps (at 25°C).

This polyurethane solution was poured onto a polyfluoroethylene resin plate with a smooth surface and dried at room temperature to obtain a uniform transparent film with a thickness of about 1 mm.

The mechanical properties of this film (conducted according to JIS K63Ol) were as follows, and it had high tensile strength. Example 2 13.95 parts of 2-hydroxyethylethylenediamine, 3.52 parts of diethanolamine and 921 parts of methyl ethyl ketone were placed in a round bottom flask equipped with a stirrer and a thermometer and uniformly dissolved therein. 880 parts of prepolymer solution was added dropwise and reacted in the same manner as in Example 1 to obtain a concentration of 30% and a viscosity of 15,000 cps (25°C
) A homogeneous transparent polyurethane solution was obtained.

A polyurethane film was obtained in the same manner as in Example 1, and its mechanical properties were measured to obtain the following values.

Example 3 200.8 parts of polybutylene adipate glycol with a molecular weight of 1004, 54 parts of 1,4-butanediol.
A solution of a urethane prepolymer (resin concentration 60%) having 1.42% free isocyanate groups was prepared in the same manner as in Example 1 using 0 parts of tolylene diisocyanate, 159.8 parts of tolylene diisocyanate, and 276.4 parts of methyl ethyl ketone. Obtained.

Then, 2-hydroxypropylethylenediamine 14
．． In the same manner as in Example 1, 807 parts of the above urethane prepolymer solution was added to a mixed solution of 51 parts of diisopropanolamine, 4.09 parts of diisopropanolamine, and 850 parts of methyl ethyl ketone and reacted to give a concentration of 30% and a viscosity of 570 cps (at 25°C). )
A polyurethane solution was obtained.

The mechanical properties of a film produced from this polyurethane solution in the same manner as in Example 1 were as follows.

Example 4 Polyoxytetramethylene glycol (molecular weight 1989
), 177.5 parts of a propylene oxide adduct of bisphenol A (molecular weight 355), 190 parts of tolylene diisocyanate, and 1548 parts of methyl ethyl ketone in the same manner as in Example 1 to obtain 0.00 free isocyanate groups.
A solution of urethane prepolymer containing 27% (concentration 46
．． 8%).

In a separate flask, 2.57 parts of 2-hydroxypropylethylenediamine, 5.78 parts of diisopropanolamine, and 769 parts of methyl ethyl ketone were placed, and 1,353 parts of the above urethane prepolymer solution was added in the same manner as in Example 1 to react. 30%, viscosity 225 cps (25°C)
A homogeneous and transparent polyurethane solution was obtained. Example 5 880 parts of the urethane prepolymer solution obtained in Example 1 was
2-hydroxyethylethylenediamine 5.23 parts, 1
・Add to a mixed solution of 9.72 parts of 6-hexamethylene diamine, 3.52 parts of diethanolamine, and 923 parts of methyl ethyl ketone and react in the same manner as in Example 1 to obtain a polyurethane solution with a concentration of 30% and a viscosity of 1510 cps (25°C). I got it.

A film produced from this polyurethane solution in the same manner as in Example 1 had the following mechanical properties.

As is clear from the raw materials used, the polyurethane solutions shown in Examples 1 to 5 all contain at least two hydroxyl groups and at least two urea bonds in one polymer molecule. It is something.

Comparative Example 1 1353 parts of the urethane prepolymer solution (resin content 46.8%) obtained in Example 4 was added to a mixed solution of 5.87 parts of 1,3-butanediol and 772 parts of methyl ethyl ketone. React at 75°C for 70 hours to obtain a concentration of 30%.
A polyurethane solution with a viscosity of 140 cps (25° C.) was obtained.

The obtained polyurethane has hydroxyl groups at both ends of the molecule, but does not contain urea bonds. Comparative Example 2 920 parts of the urethane prepolymer solution (resin content 60%) obtained in Example 1 was added to a mixture of 16.1 parts of glycerin and 957 parts of methyl ethyl ketone, and the mixture was heated at 70°C for 6 hours.
After 0 hours of reaction, the concentration was 30% and the viscosity was 360 cps (25
A polyurethane solution of .

The mechanical properties of a film produced from this polyurethane solution in the same manner as in Example 1 were as follows.

The polyurethane obtained here contains about 12 hydroxyl groups in one molecule, but does not contain urea bonds.

Comparative Example 3 920 parts of the urethane prepolymer solution (resin content 60%) obtained in Example 1 was mixed with 11 parts of ethylenediamine and 946
When the mixture was gradually added dropwise to a mixed solution of methyl ethyl ketone at 25 to 30° C. over about 50 minutes, the viscosity of the reaction system increased and the reaction system became a gel.

Therefore, this was diluted twice with methyl ethyl ketone, but a homogeneous solution was not obtained, but instead a non-uniform solution in which the gel-like polymer was suspended in a highly viscous polyurethane solution.

Furthermore, when 100 parts of ethyl acetate was added to this, it became cloudy and it was found that it could not be used as a vehicle for printing ink. This polyurethane contains urea bonds in its molecule, but no hydroxyl groups. Comparative Example 4 341.5 parts of polyoxytetramethylene glycol with a molecular weight of 1948, 78.9 parts of 1,4-butanediol, and 1400 parts of methyl ethyl ketone were mixed, then 179.6 parts of tolylene diisocyanate was added, and the mixture was heated at 75°C. 5
The reaction was allowed to proceed for 0 hours.

In this reaction, the ratio of hydroxyl groups to 1 mol of isocyanate groups is 10194 mol, and both ends of the resulting polyurethane molecule are hydroxyl groups, and no urea bond is included. The polyurethane solution obtained here had a concentration of 30% and a viscosity of 365 cps (at 25°C).

Example 6 (Ink Test) Using the polyurethane solutions of Examples 1 to 5 and Comparative Examples 1, 2, and 4 as vehicles, printing inks were prepared according to the following formulation.

1 The above raw materials were placed in a diamond-shaped ball mill with an internal volume of 500 m1 and kneaded for 16 hours to obtain a printing ink (referred to as "one-component printing ink").

On the other hand, an ethyl acetate solution of triisocyanate, which is a reaction product of 1 mol of trimethylolpropane and 3 mol of tolylene diisocyanate ("Coronate L" manufactured by Nippon Polyurethane Industries, Ltd., concentration 7.5%, isocyanate group content 13. 2%) 2.2 parts of the above one-component printing ink 10
0 parts and mixed uniformly to obtain a printing ink (this is referred to as a "two-component printing ink").

These printing inks were used to print on polypropylene film, polyethylene film, polyester film, and nylon film that had been subjected to corona discharge treatment using a bar coater and dried at 70 to 75°C for 5 seconds using an infrared lamp to obtain printed matter. Ta.

The following tests were carried out on the obtained printed matter, and Tables 1-
The results shown in Table 4 were obtained.

(1) Sekisui Cellotape # manufactured by Sekisui Chemical Co., Ltd. on the adhesive printing surface
300 (width 24 m0) was applied, and one end of this zero tape was rapidly peeled off in a direction perpendicular to the printed surface, and the state of the printed surface was observed.

(1) Surface strength The printed surface was observed when it was hit with a melon to the extent that the film did not tear. (111) Non-adhesive The presence or absence of stickiness on the printed surface due to non-adhesive fingers was observed.

(1V Water Resistance) The surface condition of the printed matter was observed after it was immersed in water at 30°C for 24 hours.

(Oil resistance) The surface condition of the printed matter was observed after it was immersed in rapeseed oil for 24 hours at room temperature (approximately 25°C).

(VI) Acid resistance After immersing the printed matter in a 5% acetic acid aqueous solution at room temperature for 24 hours, the surface condition was observed.

(Vji) Alkali resistance After immersing the printed matter in a 5% aqueous solution of caustic soda at room temperature for 24 hours, the surface condition was observed.

) 1 rating ◎・・・Extremely good, no abnormalities ○
・・・・・・Good condition, almost no abnormalities, usable for practical use△・・・
...Slightly defective ×...Poor The one-component and two-component ink prints of Examples 1, 2, 3, and 4 in Table 4 were immersed in hot water at 90°C for 30 minutes, but no abnormalities were observed. However, in the one-component and two-component inks of Comparative Examples 1 and 2, part of the printed surface peeled off.

Claims (1)

[Claims] 1. Polyhydroxy compound, organic polyisocyanate,
In a method for producing an organic solvent solution of polyurethane from a chain extender, a polymerization terminator, and an organic solvent, the general formula ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_1 represents an alkylene group of C_2 to C_6, and R
_2 and R_3 represent H, a hydroxyethyl group, or a hydroxypropyl group. However, at least one of R_2 and R_3 is not H. ) and the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (R_4, R_5 represent hydroxyethyl group, hydroxypropyl group.) A product characterized by using a polymerization terminator represented by A method for producing an organic solvent solution of polyurethane having a molecular weight of 5,000 to 100,000 and having at least two urea bonds and at least two hydroxyl groups in the molecule.