JPH03296577A - Polyurethane for printing ink - Google Patents

Abstract

PURPOSE:To improve the adhesiveness to objects, hydrolysis resistance and low-temperature flexibility of a polyurethane for printing ink which is obtained by reacting an organic diisocyanate, a high molecular weight polyol and a chain extender by using a specific high molecular weight polyol. CONSTITUTION:In a polyurethane for printing ink which is usually obtained by reacting an organic diisocyanate (e.g. isophorone diisocyanate), a high molecular weight polyol and a chain extender (e.g. isophoroneamine), use is made of, as the high molecular weight polyol, an aliphatic polycarbonate polyol in which repeating units of formula I and repeating units of formula II are contained in the ratio of 9:1 to 1:9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyurethane for printing ink. More specifically, the present invention relates to a polyurethane for printing ink that has excellent adhesion to a wide range of adherends such as polyester and nylon, and has excellent hydrolysis resistance and low-temperature flexibility.

[Prior art and problems to be solved by the invention] In general, polyester polyurethane has superior adhesion to various adherends compared to polyether polyurethane.
On the other hand, in applications that require hydrolysis resistance or flexibility, there are problems with crystal whitening and crystal shrinkage.
Furthermore, the adhesion to non-polar adherends tends to be poor. Although polycarbonate polyols have excellent hydrolysis resistance, they pose problems due to their crystallinity in applications that require flexibility.

[Means to solve the problem]

As a result of intensive research to solve these problems, the present inventors found that (A) ÷O+CH as a repeating unit.
2-h-OC÷ and (B) ÷ 0-(-CH2
→It consists of TOC÷, and the ratio of A and B is 1:9 to 9:1.
The present invention was completed based on the discovery that a printing ink with excellent hydrolysis resistance and low-temperature flexibility can be obtained by using a polyurethane containing an aliphatic copolycarbonate polyol as a constituent unit.

That is, the present invention provides a polyurethane for printing ink obtained by reacting an organic diisocyanate, a high molecular weight polyol, and a chain extender, in which the high molecular weight polyol has a repeating unit of (A) ÷ O-(-CHz +O
This invention relates to a polyurethane for printing ink, characterized in that it contains an aliphatic copolycarbonate polyol consisting of C÷ and (B)÷0,000 CH2±OC÷, and the ratio of A to B is from 9:1 to 1:9.

The aliphatic copolycarbonate polyol used in the present invention can be used in Polymer Review (P.
1,6 by various methods described in Vol. 9, pages 9-20 (1964).
-Synthesized from hexanediol and 1,5-bentanediol.

Further, it is necessary that the ratio of A and B is 9=1 to 1:9. If the ratio of A and B is outside this range, the aliphatic copolycarbonate polyol will become crystalline and the low temperature flexibility will not be improved.

The aliphatic copolycarbonate polyol used in the present invention has an average molecular weight of 300 to 10,000, preferably in the range of 500 to 5,000.

Further, other polyols may be used in combination without any problem as long as the effects of the present invention are not impaired. Other 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, bentanediol, hexanediol, octanediol, 1°4
- Polyester polyol obtained by dehydration condensation reaction from saturated and unsaturated low molecular weight glycol Mk dibasic acids such as butynediol, 2-ethyl-13-hexanediol, bisphenol A, diethylene glycol, triethylene glycol, dipropylene glycol, etc. Class: Known polyols such as polyester polyols obtained by ring-opening polymerization of a cyclic ester compound can be mentioned.

The organic diisocyanate used in the present invention includes 2
, 4-tolylene diisocyanate, 2゜6-tolylene diisocyanate, diphenylmethane 4.4''-'; isocyanate, naphthalene-1゜5-diisocyanate,
Aromatic diisocyanates such as 3,3'-dimethyl 4゜4'-biphenylene diisocyanate; Aromatic alicyclic diisocyanates such as xylylene diisocyanate and phenylene diisocyanate; i4.4'-methylene biscyclohexyl diisocyanate (hydrogenated MDr), hexa Examples include aliphatic diisocyanates such as methylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and cyclohexane diisocyanate (hydrogenated XDI).

Chain extenders used in the present invention include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-
Examples include diamine. In addition, diamines having a hydroxyl group in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-propylenediamine, di-2-hydroxyethylethylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine etc. can also be used in the same manner as the chain extenders described above. Furthermore, if necessary, as a polymerization terminator, a dialkylamine, for example,
Di-n-butylamine and the like can be used.

As a method for producing the polyurethane for printing ink of the present invention, a polyurethanization reaction technique known in the polyurethane industry is used. For example, by reacting a high molecular weight polyol and an organic diisocyanate at room temperature to 200°C, an NGO-terminated urethane prepolymer is synthesized,
Add a chain extender to this and further increase the molecular weight at room temperature to 200 ° C to obtain the desired urethane. Alternatively, add a high molecular weight polyol, an organic diisocyanate, and a chain extender all at once. Room temperature ~ 200°C
There is a one-shot method in which the desired urethane is obtained by reacting with In these reactions, it is of course possible to use an appropriate amount of a polymerization catalyst known in the urethanization reaction, typified by a secondary amine or an organic metal salt such as tin or titanium, if necessary. Further, these reactions are preferably carried out using a solvent; aromatic solvents such as benzene, toluene, and xylene, which are commonly known as solvents for printing inks; ester solvents such as methyl acetate and butyl acetate; acetone, methyl ethyl ketone,
Examples include ketone solvents such as methyl isobutyl ketone,
These solvents may be used alone or in combination. At this time, if necessary, a monohydric alcohol or the like may be used as a denaturing agent to adjust the molecular weight.

When the polyurethane for printing ink of the present invention is synthesized by the prepolymer method, the proportion of the chain extender and/or polymerization terminator to be used is the isocyanate present at both ends of the prepolymer, with respect to the NCO groups at both ends of the prepolymer. The total equivalent of amino groups in the chain extender and/or polymerization terminator is adjusted to 1.01 to 1.30 equivalents per equivalent of the group.

The molecular weight of the polyurethane thus obtained was 8.0
It is preferable to adjust the value within the range of 00 to 50.000.

To the polyurethane solution obtained in this way, colorants, solvents, surfactants, waxes, and other additives to improve ink fluidity and film surface properties are appropriately blended. The printing ink can be obtained using a ball mill, an attriter, a sand mill, etc. This printing ink exhibits excellent adhesion and lamination suitability to films such as polyester and nylon, and also has excellent properties such as bronking resistance, hydrolysis resistance, and low-temperature flexibility.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples.

Note that all parts and percentages used in the examples are based on weight unless otherwise specified. In addition, various measurements were made as follows.

・Adhesiveness Adhesion to polyester film and nylon film was measured. The printing inks produced in Examples and Comparative Examples were applied to each film and dried, a cut of 1 cm width was made with a cutter, cellophane tape was pressed onto the film, and then the film was peeled off and the state of peeling was visually determined.

The criteria for judgment are as follows.

Peel off cellophane tape ・・・・・・・・・ ×
Will not peel off with sellotape...○
・Hydrolysis resistance After leaving the resulting printing ink in an atmosphere with a relative humidity of 95% and a temperature of 70°C for 10 weeks, surface roughness, surface cracks, peeling, etc. were examined and judged based on the following criteria. .

No change is observed ・・・・・・・・・ ◎Slightly sticky ・・・・・・・・・ 0 There is some stickiness on the surface, but it does not reach the level of peeling.
× There are cracks and peeling with a large amount of flaking...××
- Low-temperature flexibility: The film coated with the printing ink was rubbed by hand in a thermostatic box at 30°C, and the state of the surface coated with the printing ink was visually observed and judged based on the following criteria.

No change is observed. ○ Cracks and peeling are observed. In the reactor, 1.
472 parts (4.0 mol) of 6-hexanediol and 1
．． Add 416 parts (4.0 mol) of 5-bentanediol, and add 1.84 parts (0.08 mol) of metallic sodium at 70 to 80°C.
mol) was added under stirring. After complete reaction of the sodium, 472 parts (8.0 mol) of diethyl carbonate were introduced. When the reaction temperature was raised to 95-100°C, ethanol began to distill out. The temperature was gradually increased to 160°C in about 6 hours. During this time, ethanol containing about 10% diethyl carbonate was distilled out. Thereafter, the pressure in the reactor was further reduced to 10 m+nHg or less, and the reaction was carried out at 200° C. for 4 hours with strong stirring. After cooling, the produced polymer was dissolved in dichloromethane, neutralized with dilute acid, washed with water several times, dehydrated with anhydrous sodium sulfate, the solvent was distilled off, and further 2 to 3 wHg
, and dried at 140°C for several hours.

The molecular weight of the obtained aliphatic copolycarbonate polyol was 2,000. (Referred to as PCDL-A.)
Similarly, using 1,5-bentanediol and diethyl carbonate, a molecule of 1t (2,000 PCDL-B
A PCDLC of 12,000 molecules was synthesized using 1,6-hexanediol and diethyl carbonate.

Polyurethane -4500 parts of the aforementioned PCDI and 111 parts of isophorone diisocyanate were mixed and reacted at 105°C for 6 hours to obtain a urethane prepolymer with an NC of 0% of 3.43. Next, 1020 parts of toluene and 510 parts of methyl ethyl ketone were added to make a homogeneous solution, and then 37.3 parts of isophoronediamine and 4.8 parts of di-n-butylamine were added dropwise at room temperature. After completion of the dropwise addition, the mixture was reacted at 40°C for 2 hours to obtain polyurethane resin solution A. The number average molecular weight of the obtained polyurethane was 20.000.

In the same manner, replace PCOL-A with PCDL-B.
Polyurethane resin solutions B and C1D as shown in Table 1 were synthesized using polyester polyol (manufactured by Dainippon Ink, Polylite 0DX-668) consisting of a condensate of PCOL-C, 1,4-butanediol and adipic acid. .

The number average molecular weight of each polyurethane is 20,00
It was 0.21,000.20.500.

Example 1 Using polyurethane resin solution A, the formulation shown in Table 1 was prepared. Each raw material was weighed, placed in a ball mill with an internal volume of 500 d, and kneaded for 18 hours to obtain printing ink A. The printing ink A was coated on a polyester film and a nylon film using a bar coater and then dried to obtain printed matter. The physical properties of the resulting printed material, including adhesion, ml hydrolysis, and low-temperature flexibility, were measured. The results are shown in Table 2.

Comparative Examples 1 to 3 Printing inks B, C, and D were prepared in the same manner as in Example 1, except that polyurethane resin solutions B, C, and D were used in place of polyurethane resin solution A in Example 1. Table 2 shows the results of measuring each physical property using these inks.

Table 1 Polyurethane resin solution A Pigment (titanium oxide) Coronate L" Methyl ethyl ketone Ethyl acetate toluene 10 5 17° 10° parts 5 5 * Triisocyanate which is a reaction product of 1 mole of trimethylolpropane and 3 moles of tolylene diisocyanate 75% ethyl acetate solution.

(Made by Nippon Polyurethane Industries) Margin below Margin below Table 2 Procedural amendment (voluntary) April λ6, 1990

Claims (1)

[Claims] 1. In a polyurethane for printing ink obtained by reacting an organic diisocyanate, a high molecular weight polyol, and a chain extender, the high molecular weight polyol is used as a repeating unit, (A) ▲ A mathematical formula, a chemical formula, a table, etc. ▼ and (B) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ A polyurethane for printing ink characterized by containing an aliphatic copolycarbonate polyol in which the ratio of A and B is 9:1 to 1:9. .