JPH0794526B2 - Method for producing polyurethane resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyurethane-based resin, and more specifically, to a silicone-modified polyurethane-based resin excellent in non-adhesiveness, blocking resistance and flexibility. For the purpose of provision.

(Prior Art) Conventionally, polyurethane-based resins have been widely used as binders for various coating agents, paints, inks, etc., films, molded products, etc., and polyurethane-based resins suitable for each application have been proposed.

These polyurethane-based resins are basically obtained by reacting a polyol component, a polyisocyanate component and, if necessary, a chain extender, and a polyurethane-based resin having various physical properties depending on the type and combination of these components. Is provided.

(Problems to be Solved by the Invention) However, regarding the use of the polyurethane resin,
For example, like a heat-resistant layer of a heat-sensitive recording material or a magnetic recording medium,
In some cases, non-adhesion to the thermal head, blocking resistance between films, etc. are required, and in these applications, sufficient flexibility for forming a thin film is usually required at the same time.

However, in order to impart high non-adhesiveness and the like, it is necessary to introduce an aromatic component and many polar bonds in the polyurethane chain, and on the contrary, flexibility is often sacrificed.

Therefore, there is a demand for the development of a polyurethane-based resin that is excellent in high-temperature non-adhesiveness, blocking resistance, and the like, and that also has excellent flexibility.

The present inventor has solved the drawbacks of the prior art as described above, and as a result of earnest research to meet the above demand, as a result of forming a polyurethane resin using a specific polyol component, the object of the present invention was achieved. I found that.

(Means for Solving Problems) That is, according to the present invention, when a polyurethane resin is produced by reacting a polyol component, a polyisocyanate component, and optionally a chain extender component, a polyol component or a chain extender component is used. At least part of which is a siloxane polyol component represented by the following formulas (1) and / or (2).

However, R in the formula is an alkyl group, and R'is a hydrogen atom or
C _{1 to} C ₅ alkyl group, k = 1 to 250, l = 0
To 5, m in the formula (1) is 1 to 50, and n is 1 to 3
In the formula (2), m is 0 to 50, and n is 2
Is an integer from 3 to 3.

(Function) A polyurethane-based resin excellent in non-adhesiveness and blocking resistance while maintaining excellent flexibility of the polyurethane-based resin by engaging a polysiloxane bond with the main chain of the polyurethane-based resin as a pendant Will be provided.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments of the present invention.

The polyurethane resin produced in the present invention and having as a pendant the group of the siloxane compound represented by the above formula (1) and / or (2), which characterizes the present invention, is a polyol, polyisocyanate, and optionally a chain extender. Is obtained by using the siloxane compound of the above formula (1) and / or (2) as all or a part of the polyol or the chain extender when the above is reacted to obtain a polyurethane resin.

The siloxane compounds of the above formulas (1) and (2) are commercially available at present, and are easily available from the market.
Both can be used in the present invention. Further, an intermediate obtained by reacting the siloxane compound as described above with a polyisocyanate as described below so that at least one of the reactive group of the siloxane compound or the isocyanate group of the polyisocyanate group remains, for example, a bifunctional siloxane compound. And a polyfunctional polyisocyanate reacted with an isocyanate group in a rich manner, or conversely, an intermediate obtained by causing a reactive group of a siloxane compound to be reacted in a rich manner can be similarly used in the present invention.

As the polyol which may be used in combination with the siloxane compound represented by the formula (1) and / or (2), any conventionally known polyol for polyurethane may be used. For example, as a preferable one, the terminal group is a hydroxyl group and the molecular weight is 300 to
4,000 polyethylene diadipate, polyethylene propylene adipate, polyethylene butylene adipate, polydiethylene adipate, polybutylene adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, polytetramethylene ether glycol, poly-ε- Examples thereof include caprolactone diol, polyhexamethylene adipate, carbonate polyol, polypropylene glycol and the like, and those containing an appropriate amount of polyoxyethylene chain in the above polyol.

As the organic polyisocyanate, any conventionally known one can be used, but preferred examples include 4,4′-diphenylmethane diisocyanate (MDI), water-added MDI, isophorone diisocyanate, 1,3-xylylene diisocyanate, 1 , 4-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, etc., or these organic polyisocyanates Urethane prepolymers obtained by reacting low molecular weight polyols and polyamines to form terminal isocyanates can of course be used.

As the chain extender, any conventionally known one can be used, but for example, preferred are ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, ethylenediamine, 1, 2-propylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, decamethylenediamine, isophoronediamine, m-xylylenediamine, hydrazine, water and the like.

Among the polyurethane-based resins containing the siloxane compound obtained from the above-mentioned materials as pendants, particularly preferable ones are those in which the pendant of the siloxane compound accounts for about 1.0 to 50% by weight in the polyurethane resin molecule. If the pendant is less than about 1.0% by weight, the desired object of the present invention such as non-adhesiveness and blocking resistance will be insufficiently expressed, while if it exceeds 50% by weight, the flexibility of the resulting polyurethane resin will be low. Is insufficient, which is not preferable.

The preferred ones have a molecular weight of 20,000 to 500,000, and the most preferred ones have a molecular weight of 20,000 to 250,000.

Further, in the present invention, the siloxane compound and polyisocyanate are reacted in an isocyanate-rich state to obtain a polyurethane resin having at least one free isocyanate group, which is used in combination with another film-forming resin. Can also be used as a modifier thereof.

The polyurethane resin obtained in the present invention containing the above siloxane compound as a pendant can be easily obtained by a conventionally known production method. These polyurethane-based resins may be prepared without a solvent or may be prepared in an organic solvent, but in the process, by preparing in an organic solvent, the resulting solution can be directly used for various purposes. It is advantageous because it is available.

Preferred as such an advantageous solvent are methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, etc., and acetone. , Cyclohexane, tetrahydrofuran, dioxane, methanol, ethanol, isopropyl alcohol, butanol, toluene, xylene, dimethylformamide, dimethylsulfoxide, perchlorethylene, trichloroethylene, methylcellosolve, butylcellosolve, cellosolve acetate and the like can also be used.

The polyurethane resin obtained by the present invention as described above, although having excellent non-adhesiveness and blocking resistance, is easily soluble in various organic solvents and can form an excellent flexible film. it can.

Therefore, a binder for forming a magnetic layer of a magnetic recording medium such as a magnetic tape, a back coat formed on the back surface of the magnetic recording medium, a binder such as a transfer film, a heat-resistant layer for preventing adhesion of a thermal head, a material for synthetic leather. It is very useful as a fiber coating agent, a surface treatment agent, the formation of a release layer such as release paper, a paint, a binder for printing ink, and the like.

Next, one example of the use of the polyurethane resin obtained in the present invention
The formation of a heat-resistant layer of a heat-sensitive recording material such as a heat transfer film will be described as a seed.

A heat-sensitive recording material is a substrate film such as a polyester film provided with a transfer ink layer or a sublimation transfer dye layer on one surface, and an image layer is heated by a thermal head from the back side to transfer the ink layer or dye to the transfer material. Then, a mono-color or multi-color image is formed, and during transfer by the thermal head, the thermal head adheres to the back surface and causes various troubles.

The polyurethane-based resin of the present invention has excellent flexibility and, in particular, has excellent adhesiveness at elevated temperature,
It is ideal for such purposes. Of course, this example is just 1
However, the application of the polyurethane resin of the present invention is not limited to the above examples.

For the formation of the heat-resistant layer, it is preferable to use a coating material formed by dissolving the polyurethane-based resin of the present invention alone or a mixture with other resin in the medium as described above, or otherwise dispersing it. The concentration of the total film forming resin in the paint is preferably about 10 to 55% by weight, and the polyurethane resin containing the siloxane compound of the present invention as a pendant is about 1 to 100 per 100 parts by weight of these film forming resins. It can be used in a proportion of parts by weight.

As the film-forming resin, various conventionally known film-forming resins can be used in combination, and any of these can be used, for example, vinyl chloride resin, vinylidene chloride resin, vinyl chloride / vinyl acetate / vinyl alcohol. Copolymer resin, alkyd resin, epoxy resin, acrylonitrile-butadiene resin, polyurethane resin, polyurea resin, nitrocellulose resin, polybutyral resin, polyester resin, fluorine resin, melamine resin, urea System resins, acrylic resins, polyamide resins, and the like. In particular, when the polyurethane resin having the siloxane compound group of the present invention as a pendant has a free isocyanate group, in the structure thereof,
A resin having a reactive group capable of reacting with an isocyanate group is preferably used. Any of these resins may be used alone or as a mixture, and may be a solution or dispersion in an organic solvent.

The heat-resistant layer-forming coating material, as long as the above-mentioned components are essential components, other subcomponents other than the above, for example, pigments, extender pigments, plasticizers, antistatic agents, surfactants, lubricants, crosslinking agents,
It may contain any additives such as an anti-aging agent, a stabilizer, a foaming agent and an antifoaming agent.

The method itself for forming the heat-resistant layer may be the same as a conventionally known method, and it is preferable to form the heat-resistant layer to a thickness of about 0.1 to 10 μm.

As the substrate sheet to be used, any conventionally known one can be used, for example, a polyester film, a polypropylene film, a cellulose triacetate film, a cellulose diacetate film, a polycarbonate film or the like having a thickness of 5 to 50 μm is arbitrarily used. be able to.

The heat-sensitive recording material may be any known method except that the polyurethane-based resin as described above is used for forming the heat-resistant layer,
For example, the heat-sensitive recording layer can be formed from a conventionally known binder resin, a dye or pigment, an organic solvent and various necessary additives according to a conventionally known method.

For example, as the binder resin, a resin such as the above film-forming resin can be used, an organic solvent such as the above can be used as an organic solvent, and an additive such as the above can be used as an additive. , Azo-based, phthalocyanine-based, quinacridone-based, organic pigments such as polycyclic pigments, carbon black, iron oxide, yellow lead, inorganic pigments such as cadmium sulfide can be used, and as the dye, various conventionally known dyes and Sublimable dyes, disperse dyes and the like can be used.

(Effect) The polyurethane resin obtained as described above has excellent solvent solubility, gives an excellent flexible film, and has excellent high temperature non-adhesiveness, blocking resistance, etc. It is useful for various applications as described above.

(Examples) Next, the present invention will be described more specifically with reference to Examples, Comparative Examples, and Usage Examples. In the text, parts and% are based on weight.

Example 1 (K is a value at which the molecular weight becomes 5,200.) 150 parts of polydimethylsiloxane polyol (molecular weight 5,200) having the above structure and 12 parts of 1,4-butanediol, 200 parts of methyl ethyl ketone and 50 parts of dimethyl. Dissolve in a mixed solvent with formamide and mix well at 60 ° C with 42 parts of water-added MDI dissolved in 128 parts of dimethylformamide, gradually apply, and react at 80 ° C for 5 hours Then, the polyurethane resin solution of the present invention was obtained.

The solution had a viscosity of 16,500 cps (25 ° C) at 35% solids.

The film obtained from this solution has a breaking strength (kg / cm ² )
At 360, the elongation at break (%) was 350 and the softening point was 92 ° C.

Example 2 (K is a value at which the molecular weight becomes 5,200.) 75 parts of polydimethylsiloxane polyol (molecular weight 5,200) having the above structure, 75 parts of polybutylene adipate (molecular weight 2,000) and 15 parts of 1,4-butanediol are added. It is dissolved in a mixed solvent of 250 parts of methyl ethyl ketone and 50 parts of dimethylformamide, and while stirring well at 60 ° C, 56 parts of water-added MDI dissolved in 110 parts of dimethylformamide are gradually applied. After completion of the lowering, the reaction was carried out at 80 ° C. for 5 hours to obtain a polyurethane resin solution of the present invention.

This solution had a viscosity of 31,000 cps (25 ° C) at 35% solids.

The film obtained from this solution has a breaking strength (kg / cm ² )
At 460, the elongation at break (%) was 400 and the softening point was 105 ° C.

Example 3 (K is the value at which the molecular weight becomes 4,500.) 4 parts of the polydimethylsiloxane polyol (molecular weight 4,500) having the above structure, 146 parts of polybutylene adipate (molecular weight 2,000) and 10 parts of 1,4-butanediol are added. It is dissolved in a mixed solvent of 150 parts of methyl ethyl ketone and 100 parts of dimethylformamide, and while stirring well at 60 ° C, 47 parts of water-added MDI dissolved in 134 parts of dimethylformamide is gradually applied. After completion of the lowering, the reaction was carried out at 80 ° C. for 6 hours to obtain a polyurethane resin solution of the present invention.

The solution had a viscosity of 45,000 cps (25 ° C) at 35% solids.

The film obtained from this solution has a breaking strength (kg / cm ² )
At 450, the elongation at break (%) was 410 and the softening point was 90 ° C.

Example 4 (K is a value at which the molecular weight becomes 4,800.) 4 parts of polydimethylsiloxane polyol (molecular weight 4,800) having the above structure, 146 parts of polybutylene adipate (molecular weight 2,000) and 10 parts of 1,4-butanediol are added. It is dissolved in a mixed solvent of 150 parts of methyl ethyl ketone and 100 parts of dimethylformamide, and while stirring well at 60 ° C., 46 parts of water-added MDI dissolved in 134 parts of dimethylformamide is gradually applied. After completion of the lowering, the reaction was carried out at 80 ° C. for 6 hours to obtain a polyurethane resin solution of the present invention.

The solution had a viscosity of 48,000 cps (25 ° C) at 35% solids.

The film obtained from this solution has a breaking strength (kg / cm ² )
At 420, the elongation at break (%) was 430 and the softening point was 95 ° C.

Example 5 A polyurethane resin solution of the present invention was obtained in the same manner as in Example 1 except that the following siloxane compound was used in the same amount instead of the siloxane compound in Example 1.

(K is a value at which the molecular weight becomes 5,200.) This solution had a solid content of 35% and a viscosity of 48,000 cps (25 ° C.).

The film obtained from this solution has a breaking strength (kg / cm ² )
At 420, the elongation at break (%) was 430 and the softening point was 95 ° C.

Example 6 A polyurethane resin solution of the present invention was obtained in the same manner as in Example 2, except that the same amount of the following siloxane compound was used instead of the siloxane compound in Example 2.

(K is a value at which the molecular weight becomes 5,200.) This solution had a solid content of 35% and a viscosity of 48,000 cps (25 ° C.).

The film obtained from this solution has a breaking strength (kg / cm ² )
At 420, the elongation at break (%) was 430 and the softening point was 95%.

Example 7 A polyurethane resin solution of the present invention was obtained in the same manner as in Example 3 except that the following siloxane compound was used in the same amount as the siloxane compound in Example 3.

(K is a value at which the molecular weight becomes 5,200.) This solution had a solid content of 35% and a viscosity of 48,000 cps (25 ° C.).

The film obtained from this solution has a breaking strength (kg / cm ² )
At 420, the elongation at break (%) was 430 and the softening point was 95 ° C.

Example 8 A polyurethane resin solution of the present invention was obtained in the same manner as in Example 4 except that the following siloxane compound was used in the same amount in place of the siloxane compound in Example 4.

(K is a value at which the molecular weight becomes 5,200.) This solution had a solid content of 35% and a viscosity of 48,000 cps (25 ° C.).

The film obtained from this solution has a breaking strength (kg / cm ² )
At 420, the elongation at break (%) was 430 and the softening point was 95 ° C.

Comparative Example 1 Polybutylene adipate (molecular weight 2,000) 150 parts and 1,4
-Butanediol 5 parts with 5 parts 200 parts methyl ethyl ketone
Dissolved in a mixed solvent with 0 parts dimethylformamide, 6
A solution prepared by dissolving 62 parts of water-added MDI in 171 parts of dimethylformamide while stirring well at 0 ° C. was gradually applied, and after completion of the application, reaction was carried out at 80 ° C. for 6 hours.

The solution had a solids content of 35% and a viscosity of 32,000 cps (25 ° C.).

The film obtained from this solution has a breaking strength (kg / cm ² )
It had a breaking elongation (%) of 480 at 450 and a softening point of 102 ° C.

Cut the softening point film into strips, attach a cone to the lower end of the film to 450 g / cm ² and hang it in a gear oven, then raise the temperature at a rate of 2 ° C / min. To elongate the film. Is rapidly increased or the temperature is measured when the film is cut.

Comparative Example 2 100 parts of silicone resin (KS-841) manufactured by Shin-Etsu Chemical Co., Ltd. and 1 part of catalyst (PL-7) were dissolved in 1,000 parts of toluene,
It was used as a coating liquid of silicone resin.

Use Examples 1 to 8 and Comparative Use Examples 1 to 3 A coating material containing the following components was prepared, and a dried film having a thickness of 0.5 was formed on the back surface of a 15 μm-thick polyester film having a thermosensitive recording layer formed in advance. to be μm,
It was applied with a gravure coater and the solvent was dried in a dryer to form a heat resistant layer. This was cut into a predetermined width to prepare a heat-sensitive recording material using the polyurethane resin of the present invention and a heat-sensitive recording material for comparison.

Use Example 1 Resin solution of Example 1 100 parts Methyl ethyl ketone 100 parts Use example 2 Resin solution of Example 2 100 parts Methyl ethyl ketone 100 parts Use example 3 Resin solution of example 3 100 parts Methyl ethyl ketone 100 parts Use example 4 Resin of example 4 Solution 100 parts Methyl ethyl ketone 100 parts Usage example 5 Resin solution of Example 5 100 parts Methyl ethyl ketone 100 parts Usage example 6 Resin solution of example 6 100 parts Methyl ethyl ketone 100 parts Usage example 7 Resin solution of example 7 100 parts Methyl ethyl ketone 100 parts Usage example 8 Resin solution of Example 8 100 parts Methyl ethyl ketone 100 parts Comparative use example 1 Resin solution of Comparative example 1 100 parts Methyl ethyl ketone 100 parts Comparative use example 2 Resin solution of Comparative example 1 100 parts Talc 5 parts Methyl ethyl ketone 120 parts Comparative use example 3 Comparison Evaluation of 100 parts of resin liquid of Example 2 Thermal recordings obtained in Use Examples 1 to 8 and Comparative Use Examples 1 to 3 Characteristics of charges were as in Table 1 below.

The friction coefficient in Table 1 above is a measured value of the friction coefficient between the untreated surface of polyethylene terephthalate and the heat-resistant layer formed in the present invention or the comparative use example.

The sticking property was subjected to a thermal recording mounting test, and the detachability of the thermal recording material from the thermal head at the time of pressing operation between the thermal head and the thermal recording material was visually evaluated in 5 stages, and the best one was selected. It was set to 5.

As for the dirt on the head, it was subjected to a mounting test for thermal recording, and the dirt condition of the thermal head was observed.
Was evaluated in 5 levels.

From the above results, it is clear that the heat-sensitive recording material using the polyurethane resin of the present invention has a low coefficient of friction of the heat-resistant layer, low tackiness and little head contamination.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoko Goto 4-4-33 Nishi-Aoki, Kawaguchi City, Saitama Prefecture (72) Inventor Katsumi Kuriyama 1135-1, Kuri Shioma, Koshigaya City, Saitama Prefecture (56) References 63-83121 (JP, A) JP 63-289012 (JP, A) JP 62-225516 (JP, A) JP 64-75513 (JP, A)

Claims (1)

[Claims] 1. When a polyurethane resin is produced by reacting a polyol component, a polyisocyanate component and optionally a chain extender component, at least a part of the polyol component or the chain extender component is represented by the following formula (1) and And / or a siloxane polyol component represented by the formula (2), a method for producing a polyurethane resin. (Wherein R is an alkyl group, R ′ is a hydrogen atom or a C _{1 to} C ₅ alkyl group, and k = 1 to 250, l =
0 to 5, m in the formula (1) is 1 to 50, n is an integer of 1 to 3, and m in the formula (2) is 0 to 50, n
Is an integer of 2 to 3. )