JPH02160819A - Polyurethane resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in elastic properties, low- temperature properties and heat resistance by reacting a specified modified polyoxytetramethylene glycol with a polyisocyanate compound and an active hydrogen compound reactive with an isocyanate group. CONSTITUTION:A modified polyoxytetramethylene glycol having a main chain comprising repeating structural units comprising a polyoxytetramethylene group of the formula (wherein n is 3-28) and a dioxycarbonyl group [-OC(O)O-] and containing 75.5-99.3mol% oxytetramethylene group [-O(CH2)4-] and 0.7-24.5mol% dioxycarbonyl group is reacted with a polyisocyanate compound (e.g. 4,4'- diphenylmethane diisocyanate) and an active hydrogen compound reactive with an isocyanate group (e.g. 1,4-butanediol).

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to polyurethane resin compositions.

(Prior Art) Polyether is often used as a soft segment component of polyurethane resins. Among them, polyurethane resins using polyoxytetramethylene glycol are attracting particular attention because of their excellent elastic properties, low-temperature properties, and hydrolysis resistance.

However, polyoxytetramethylene glycol (hereinafter P
TMEG) has a molecular weight of 500, which is useful for polyurethane.
~4,000 and has a melting point in the range of 14 to 40°C, which crystallizes at temperatures around room temperature and becomes a wax-like solid, making it difficult to handle and work, as well as paints and coatings that require curing at room temperature. This has become a major problem in the fields of elastomers, binders, etc. This is because crystallization of PTMEG occurs during the curing reaction stage, resulting in phase separation and the reaction does not progress.

Conventionally, the solution to this problem was to add an appropriate organic solvent, but from the standpoint of pollution prevention and rationality, non-solvent systems have been trending in recent years, and these have strongly improved the crystallinity of PTMEG. desired.

On the other hand, polyurethane resin made of PTMEG is known to have poor heat resistance, which limits its field of use.
There is also a strong demand for improvement.

Tetrahydrofuran/propylene oxide copolyether is known to improve crystallinity, but [Journal of Polymer Science, ■, 857-853 (196
2) LThis polyol is a copolymer with propylene oxide, so like polypropylene oxide polyol,
It has a secondary hydroxyl group at the end, has low reactivity with isocyanate groups, and has poor polyurethane physical properties. On the other hand, JP-A-6
A copolymer of tetrahydrofuran and 3-alkyltetrahydrofuran as described in Japanese Patent No. 3-235320 has a low melting point, high reactivity with isocyanates, and the physical properties of polyurethane are comparable to those of polyurethane using PTMEG.

However, the methine proton at the side chain position of the 3-alkyltetrahydrofuran-based unit in this copolymer
Since it is relatively unstable to radicals, the heat resistance of polyurethane is not always satisfactory. Polycarbonate diol is well known as a polyol that provides a polyurethane resin with good heat resistance, but it also has a high melting point and is inferior to PTMEG-based polyurethane properties such as elastic properties, low-temperature properties, and water resistance.

(Problems to be Solved by the Present Invention) Therefore, an object of the present invention is to use a polyol that has a low melting point, is liquid at room temperature, and has high reactivity with isocyanate groups, and while maintaining the characteristics of PTMEG. The purpose is to provide a polyurethane resin with excellent heat resistance.

(Means for Solving the Problems) In view of the above-mentioned circumstances, the present inventors have made extensive studies and found that modified polyoxytetramethylene glycerol in which polyoxytetramethylene groups are linked with dioxycarbonyl groups can be used at room temperature. The polyurethane resin, which is composed of the polyol, polyisocyanate compound, and active hydrogen atom compound, maintains a liquid state and has high reactivity with isocyanate groups, and has excellent rubber elasticity and low-temperature properties, as well as excellent heat resistance, like PTMEG-based products. Heading The present invention has been arrived at.

That is, the present invention provides a repeating structure in which the main chain is composed of a polyoxytetramethylene group (0(CH2)4), (in the formula, n is 3 to 2]I8) and a dioxycarbonyl group -0CO-, Tetramethylene group -〇
Modified polyoxytetramethylene glycol containing 75.5 to 99.3 mol% of (CH2)4- and 24.5 to 0.7 mol% of dioxycarbonyl group, polyisocyanate compound, and activity to react with isocyanate groups This is a polyurethane resin composition comprising a hydrogen atom-containing compound.

The modified polyoxytetramethylene glycol which is the main component of the present invention is disclosed in Japanese Patent Application No. 63-78135 or Japanese Patent Application No. 63-78135.
161010, the composition of the main chain is 75.5 to 99.3 mol% of oxytetramethylene groups and 24.5 to 0.7 mol% of dioxycarbonyl groups. This is a condition for realizing the present invention, and the effect of the present invention is not sufficient in a composition range other than this.

The modified polyoxytetramethylene glycol has a melting point of about 10° C. or lower and is a colorless and transparent liquid at room temperature, and since it has a primary hydroxyl group at its terminal, it is highly reactive with isocyanate groups. The molecular weight is not particularly limited and is determined depending on the desired physical properties of the polyurethane resin. Generally molecular weight 500~
5000 will be selected.

On the other hand, polyisocyanate compounds have two or more isocyanate groups in the molecule, such as tolylene diisocyanate (TDI), 44-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and naphthyl diisocyanate. , hydrogenated diphenylmethane diisocyanate, etc. - polyisocyanate compounds used in the synthesis of polyurethane resins for boat fishing, and these may be used alone or in combination of two or more.

Compounds containing active hydrogen atoms that react with isocyanate groups include compounds having one or more hydroxyl or amino groups such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, xylylene glycol, and glycerin. , trimethylolpropane, ethylenediamine, propylenediamine, phenylenediamine, diaminodiphenylmethane, methylenebis(2chloroaniline), hydrazine compounds, water, and other compounds used as chain extenders in the synthesis of polyurethane resins. In addition, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, N-hydroxymethyl (meth)acrylamide, glycerin mono(di)(meth)acrylate, trimethylol mono( Di)(meth)acrylate and the like can also be mentioned.

The polyurethane resin composition of the present invention can be prepared by reacting, for example, a modified polyoxytetramethylene glycol with a polyisocyanate compound to obtain an isocyanate group-containing precursor (
It can be obtained by synthesizing a prepolymer (prepolymer) and then reacting with an active hydrogen atom compound, that is, by a two-step method, or by a conventional polyurethane resin manufacturing method such as a one-shot method in which three components are reacted simultaneously.

The reaction temperature in the above synthesis varies depending on the process, application, etc., but in the case of boat fishing it is carried out at a temperature in the range of 50 to 200°C, but in the case of the present invention, the reaction temperature is 50°C because the melting point of the modified polyoxytetramethylene glycol is low. The reaction is possible at temperatures below °C and even at room temperature.

On the other hand, although the composition ratio of each component varies depending on the target polyurethane resin, the prepolymer must contain isocyanate groups, and the isocyanate group of the polyisocyanate compound is 1 equivalent or more per 1 equivalent of hydroxyl group of the modified polyol compound, It is preferably set to 1.2 or more.

In either method, the mixing ratio of the final reactants is such that the total active hydrogen atom equivalent of the modified polyol and chain extension compound is 0.8 or more per equivalent of isocyanate group. When the active hydrogen atom-containing compound is a compound having a polymerizable unsaturated group, it is a urethane acrylate prepolymer having a polymerizable unsaturated group at the end, and is cured by irradiation with ultraviolet rays or electron beams, or by heat. In this case, the photopolymerization initiator may be benzoin, benzoin methyl ether, benzoin methyl ether, benzoin n-propyl ether, benzoin n-butyl ether, acetophenone, anthraquinone, etc. (tertiary amines, alkyl phosphines, thio'ethers, etc. if necessary). It is common to use a photo-sensitizing agent such as the following: benzoyl peroxide, di-butyl hydroperoxide, azobisisobutyl nitrile, etc. as a catalyst for thermal polymerization.

The photopolymerization reaction is often carried out at room temperature, and the modified polyoxytetramethylene glycol that constitutes the main composition of the present invention has a low melting point and is liquid at room temperature, so that the effects of the present invention can be fully realized. Urethane acrylates are useful as paints, coatings, inks, and coatings.

In the reaction, a catalyst, a stabilizer, etc. can be added as necessary. Examples of urethanization catalysts include triethylamine, tributylamine, dibutyltin dilaurate, and stannous octylate, and examples of stabilizers include ionol (BHT), distearyl dipropionate, tri(dinonyl zero phenyl) phosphite, Furthermore, when it has a polymerizable unsaturated group, a polymerization inhibitor such as hydroquinone, t-
Butylhydro, quinone, etc. can be added. Of course, inert solvents can also be used.

The polyurethane resin obtained from the modified polyoxytetramethylene glycol of the present invention has superior physical properties compared to polypropylene oxide polyols and THF/propylene oxide copolyether polyols that are liquid at room temperature, and also exhibits properties similar to those of PTMEG systems. , and has good heat resistance.

(Example) Next, the present invention will be explained in more detail with reference to Examples. In the examples, the melting point (Tm) and thermal decomposition temperature (T
d) are each DSC (DSC-8230 manufactured by Rigaku Denki).
), TO (TC; -8110), and viscoelasticity measurements were made using Rheopyblon DDV-2 (manufactured by Orientic Co., Ltd.).

The tensile test was conducted in accordance with JIS K6301 (No. 3 dumbbell).

Example 1 Modified polyoxytetramethylene glycol (molecular weight 19
93, oxytetramethylene group, 93 mol%, dioxycarbonyl group, 7 mol% L59゜9g1 Weigh 196 g of dehydrated dimethylformamide (DMF) into a 500 cc separable flask, and attach a stirring device, thermometer, and dehydration tube. Finally, N2 purge was performed and sealed. After mixing well by stirring, 22.5 g of 4.4"-diphenylmethane diisocyanate (MDI) was dissolved in 51 g of DMF and added over 30 minutes at 30°C. Thereafter, the reaction was carried out at this temperature for 1 hour, and the isocyanate was dissolved. A terminal prepolymer solution was obtained (NCO=1.32 t%).

To this solution was added 4.2 g of 1,4-butanediol (NCO1
0H=0.95 equivalent) was dissolved in 34 g of DMF and added to perform a chain extension reaction. The obtained polyurethane solution was cast into a 18 x 25 x 3 nm glass mold and heated at 60°.
After putting it in a constant temperature dryer for 118 hours and performing DMF removal and curing, it was about 0.2nuaJ! A transparent sheet was obtained. This sheet was kept at a temperature of 20° C. and a humidity of 65% for 4 days or more, and was subjected to physical property measurements.

The TG, viscoelasticity data, and tensile test results of this polyurethane resin sheet are shown in Table 1.

Comparative Example Polyoxytetramethylene glycol rPTGJ (Hodogaya Chemical Industry ■ product) (molecular weight 1945, oxytetramethylene group 100%) 56.4g, dehydrated DMF 194
DMF with an MDI of 22.5 g, with g being the same as in Example 1.
60 g solution was added to obtain a prepolymer solution (NGO
= 1.30gt%). Add this to 1゜4-butanediol 4
．． 1 g (DMF21 per NGO10H=0.95
A chain extension reaction was carried out with g solution, and a polyurethane resin sheet was obtained under the same conditions and procedures as in Example 1, and the physical properties were measured.

The measurement results are also shown in Table-1.

From the results in Table 1, the polyurethane using the modified PTMEG of the present invention has a high thermal decomposition temperature and excellent heat resistance;
It can be seen that it is an excellent elastic body similar to polyurethane resin using MEG.

Example 2 Modified polyoxytetramethylene glycol (molecular weight 19
93, oxytetramethylene group, 93 mol%, dioxycarbonyl group, 7 mol%), 1°Og was placed in a 200 cc separable flask equipped with a dehydration tube, a thermometer, and an ink-type stirring blade, and heated at 100°C. Dehydration was performed under reduced pressure for an hour, followed by vacuum break and sealing with dry N2. Temperature 70°C when left to cool
and 24-tolylene diisocyanate (TDI) 17
．． 3g was added, and a prepolymerization reaction was carried out at 70°C for 5 hours (NGO = 3.5svt%). To this, 12.4g of molten methylenebis(2-chloroaniline) was added under vigorous stirring, and the mixture was heated at 80 to 90°C. Optical mixing for 3 minutes at C, 18X2
It was poured into a 5 x 2 mm glass mold and cured at 110°C for 16 hours. The resulting translucent rubber sheet was kept at 20°C/65% RT for one week and its physical properties were measured. The results are shown in Table-2.

Table-2 Hardness 82 (TIS-^) Modulus 100% 45 (kgf/CT1)3
00% 70 (〃) Breaking strength 310 (〃) Elongation 630 (%) Example 3 Modified polyoxytetramethylene glycol (molecular weight 45
06, oxytetramethylene group, 91 mol%, dioxycarbonyl group, 9%) was placed in a 21 separable flask equipped with a condenser, a thermometer, and a stirrer, 58 g of tolylene diisocyanate, 1 hydroquinone monomethyl ether 0.6 g, and air 80° below the blowing
The reaction was carried out at C for 5 hours. Further, 25.7 g of 2-hydroxylethyl acrylate was added and reacted at 80°C for 5 hours to obtain a viscous urethane-modified prepolymer containing polymerizable unsaturated groups.

100 g of this urethane acrylate, 100 g of n-butyl acrylate, and 5 g of benzoin isobutyl ether.
were mixed to prepare a liquid resin for photocuring.

This polymer was coated on a glass plate to a thickness of about 100μ, and exposed to an ultraviolet irradiation device (conditions: output 80 w/c).
Curing was performed using a high-pressure mercury lamp (ozone-less diffused light type, irradiation distance: 6 cm, conveyor speed: 180 cm/min). The physical properties of the film using a No. 3 dumbbell and a tensile speed of 200 mm/sin are shown below.

Young's modulus 5 (kgf/c) breaking strength
18 (〃) 〃 Growth 600 (%) Hodogaya Chemical Industry Co., Ltd.

Claims (1)

[Claims] The main chain is a polyoxytetramethylene group ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, n is 3 to 28
) and a dioxycarbonyl group ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ In the repeating structure consisting of 0.7-24.5 mol%
A polyurethane resin composition obtained from a modified polyoxytetramethylene glycol, a polyisocyanate compound, and an active hydrogen atom-containing compound that reacts with the isocyanate group.