JPH06116355A - Production of polyurethane resin and molding - Google Patents

Abstract

PURPOSE:To produce a thermoplastic polyurethane resin capable of providing moldings better in appearance in extrusion molding. CONSTITUTION:A lactone-modified polyhexamethylene carbonate polyol is mixed with 1,6-hexandiol and hexamethylene diisocyanate while being stirred at a high speed, then cast into a vat and made to react and the resultant reactional product is subsequently pulverized and extruded into pellets. Thereby, the objective thermoplastic polyurethane resin capable of providing moldings better in appearance in extrusion molding is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic polyurethane resin, and more particularly to a method for producing a thermoplastic polyurethane resin capable of obtaining a molded article having an excellent appearance because less unmelted matter is generated during molding. It is about.

[0002]

2. Description of the Related Art Conventionally, thermoplastic polyurethane resins have been
Since it has many features such as high elasticity and oil resistance, it has been used in many applications as a molding material.

A thermoplastic polyurethane resin which is reacted with a high molecular weight polyol by using a polyol having a carbon number of less than 6 as a chain extender and an aliphatic diisocyanate or an alicyclic diisocyanate having excellent yellowing resistance as a diisocyanate is often prepared. Are known.

[0004]

However, the appearance of a molded article using a polyol having a carbon number of less than 6 as a chain extender is insufficient, regardless of the reaction equivalent ratio of any isocyanate group and active hydrogen. There was a problem that only molded products could be obtained.

[0005]

The inventors of the present invention have made diligent studies in view of the above situation, and as a chain extender,
It was found that, when a polyol having 6 or more carbon atoms is used instead of a polyol having less than 6 carbon atoms, a molded product having a better appearance than in the past can be obtained, and the present invention has been completed.

That is, the present invention relates to a method for producing a thermoplastic polyurethane resin, which comprises reacting an aliphatic isocyanate and / or an alicyclic isocyanate (A), a chain extender (B) and a polymer polyol (C) with the chain. Disclosed is a method for producing a thermoplastic polyurethane resin, wherein the extender (B) is a polyol having 6 or more carbon atoms.

Next, the method for producing the thermoplastic polyurethane resin of the present invention will be described in detail. As the aliphatic isocyanate and / or alicyclic isocyanate (A) used in the present invention, any conventionally known one can be used, and for example, methylene diisocyanate, ethylene diisocyanate, 1-methylethylene diisocyanate, tetramethylene diisocyanate, penta Methylene diisocyanate, 2-methylbutane-1,4-diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 2,5-dimethylhexane-1,6-diisocyanate, P, P'-cyclohexylmethane diisocyanate, 4,4'-dicyclohexylmethane Examples thereof include diisocyanate.

Among them, from the viewpoint that the thermoplastic polyurethane resin obtained has high heat resistance, for example, linear aliphatic isocyanates such as tetramethylene diisocyanate and hexamethylene diisocyanate, and alicyclic compounds such as P, P'-cyclohexylmethane diisocyanate. It is preferred to use group isocyanates. Further, it is preferable to use industrially mass-produced hexamethylene diisocyanate or the like. These isocyanates may be used alone or in combination.

As the polyol (B) having 6 or more carbon atoms, which is used in the chain extender of the present invention, any conventionally known polyol can be used. For example, 1,6-hexanediol, neopentyl glycol and octanediol can be used. , Nonanediol, decanediol, trimethylolpropane, glycerin and other aliphatic glycols, cyclohexanediol, cyclohexanedimethanol and other low molecular weight alicyclic diols, bishydroxyethoxybenzene, xylene glycol and other aromatic glycols, etc. , And mixtures thereof.

The average number of functional groups of these polyols (B) alone or in a mixture is preferably 2 or more, and the average molecular weight is preferably 50 to 400. When rubber elasticity is required for the obtained molded product, it is preferable to use an aliphatic diol. Since a chain extender having an odd number of carbon atoms in the main chain has lower physical properties and heat resistance than that of an even number, the polyol (B) is preferably a diol having 6 or more carbon atoms and an even number of carbon atoms, such as 1,6-hexane. Most preferred are diols.

A low molecular weight polyol having a main chain of 6 or more carbon atoms and a polyol having a carbon number of less than 6 can be mixed and used. In this case, the proportion of the polyol having 6 or more carbon atoms is preferably 50 mol% or more.

As the polymer polyol (C) of the present invention, any known and commonly used one can be used, and examples thereof include polycarbonate polyol, polyester polyol and polyether polyol. These polyols may be used alone or in combination. The average number of functional groups of these polymer polyols alone or in a mixture is preferably 2 or more, and the average molecular weight is 500 to
It is preferably 30,000. Particularly, the average number of functional groups is preferably about 2, and the average molecular weight is preferably 500 to 5000. Most preferred average molecular weight is 500-3
It is 000.

As the polymer polyol (C), it is particularly preferable to use a polycarbonate polyol because the thermoplastic polyurethane resin obtained is excellent in weather resistance and heat resistance.

The polycarbonate polyol can be easily obtained, for example, by subjecting a low-molecular polyol and a dialkyl carbonate or diaryl carbonate to a condensation reaction. Examples of the low molecular weight polyol include 1,6-hexanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, cyclohexanedimethanol and the like. Examples of the dialkyl carbonate or diaryl carbonate include diphenyl carbonate, dimethyl carbonate, diethyl carbonate, ethylene carbonate and the like.

As the polycarbonate polyol, for example, a lactone-modified polycarbonate polyol obtained by ring-opening addition polymerization of a lactone with a polycarbonate polyol, or a cocondensation obtained by cocondensing a polycarbonate polyol with another polyester polyol or polyether polyol, etc. Examples include polycarbonate polyols.

As the polycarbonate polyol, a lactone-modified polycarbonate polyol is preferable in that bleeding is less likely to occur during molding of the obtained thermoplastic polyurethane resin and the appearance of the film is improved.

As the polyester polyol, for example, ethylene glycol, propylene glycol, 1,4-
Butanediol, 1,5-pentanediol, 1,6-
One or more of hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, cyclohexanedimethanol or other low molecular weight diol components and, for example, glutaric acid, adipic acid, pimelic acid, suberic acid, A polycondensation product with one or more low molecular weight dicarboxylic acids such as sebacic acid, terephthalic acid, and isophthalic acid, or a lactone polyol obtained by ring-opening polymerization of a lactone, for example, polypropiolactone polyol, polycaprolactone polyol, poly Examples thereof include valerolactone polyols, but are not limited thereto.

Examples of the polyether polyol include polypropylene ether polyol, polytetramethylene ether polyol, hexamethylene ether polyol and the like.

The present invention is particularly applicable to the continuous production of a thermoplastic polyurethane resin using a highly crystalline raw material such as a polycarbonate polyol as a polymer polyol and a linear aliphatic diisocyanate as an aliphatic isocyanate / or an alicyclic diisocyanate. It is effective, and the effects of the invention are more easily exhibited.

The production of the thermoplastic polyurethane resin of the present invention can be carried out by the usual production of thermoplastic polyurethane. For example, a polymer polyol (C) with excess isocyanate (A) in advance at a temperature of 120 ° C. or lower, preferably 100 ° C. or lower, is used as a prepolymer of a terminal isocyanate and a chain extender (B). Liquid (prepolymer method), or a two-liquid (one-shot method) of a polyol compound obtained by mixing a polymer polyol (C) and a chain extender (B) and an isocyanate (A), and mixing and stirring, It can be produced by a method in which the above raw materials are weighed with a metering pump, vigorously mixed and stirred, poured on a vat, further reacted at a temperature of, for example, 80 to 200 ° C., preferably 120 to 180 ° C., and then ground.

Further, for example, the above raw materials are supplied to an extruder set at 80 to 250 ° C., preferably 120 to 250 ° C., and the raw materials are kneaded in the extruder and polymerized while being conveyed to die a thermoplastic polyurethane. It can also be manufactured by extrusion.

The effect of the present invention is that when compared to an intermittent production method such as a batch type production method, a continuous production method in which the equivalent ratio of an isocyanate group and active hydrogen is relatively liable to change over time, the effect is not produced during molding. The effect that the melt is extremely generated and the thermoplastic polyurethane resin having a better appearance of the molded product can be stably obtained is more likely to be exhibited.

In the production method of the present invention, the reaction equivalent ratio of the isocyanate group and the active hydrogen is not particularly limited, but is usually 0.95 to 1.05, preferably 0.96 to 1.
It is 04. With the above reaction equivalent ratio, a polyol having a carbon number of less than 6 is used as a chain extender, and when the reaction equivalent ratio of the isocyanate group and active hydrogen is> 1.0, unmelted matter is less likely to occur during molding and the appearance is better. Another effect is that it is easy to obtain a thermoplastic polyurethane resin that is easy to obtain a good molded product. Therefore, a thermoplastic polyurethane resin having the same performance as the conventional one can be obtained without requiring a highly accurate raw material supply device for controlling a special reaction equivalent ratio.

Further, according to the present invention, the disadvantage that the flow starting point is low and the molding is difficult because the molecular weight of the obtained thermoplastic polyurethane resin is too small has been solved.

If the active hydrogen compound [polymer polyol (C) or chain extender (B)] absorbs moisture, the strength of the polyurethane obtained by foaming becomes low. In that case, 100 ° C. in advance. It is preferable to dehydrate under reduced pressure at a temperature around.

The catalyst may or may not be used, but it often gives better results. As the catalyst, any commonly used urethanization catalyst can be used,
For example, bismuth, lead, tin, iron, antimony, uranium, cadmium, cobalt, thorium, aluminum, mercury,
Zinc, nickel, cerium, molybdenum, vanadium,
Examples thereof include organic compounds such as copper, manganese, zirconium and calcium, and inorganic compounds. Preferred catalysts are organometallic compounds, especially dialkyltin compounds. Typical organotin catalysts include, for example, stannous octoate,
Examples thereof include stannous oleate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, dibutyltin mercaptopropionate, dibutyltin dodecyl mercaptide and the like.

The amount of the catalyst used is determined according to the properties of the other raw materials, the reaction conditions, the desired reaction time, etc., and is not particularly limited, but generally the catalyst is the total weight of the reaction mixture. About 0.0001 to about 5% by weight, and preferably about 0.001 to 2% by weight, on the active hydrogen compound side.

The thermoplastic polyurethane resin obtained in the present invention has a flow starting temperature of 125 ° C. because of its excellent heat resistance.
The above is preferable.

In the thermoplastic polyurethane resin obtained in the present invention, other additives such as antioxidants, UV inhibitors, fillers and reinforcing fibers can be used as required. These auxiliary materials are usually mixed and used on the active hydrogen compound side.

The thermoplastic polyurethane resin obtained by the production method according to the present invention can be easily molded by a commonly used injection molding machine, extrusion molding machine, blow molding machine, calender molding machine or the like.

The thermoplastic polyurethane resin obtained according to the present invention is excellent in the appearance of molded articles and resistance to yellowing, and is therefore used for fibers, films, sheets, hoses, tubes, synthetic leather, various industrial parts (belts, etc.), automobile parts (dust). Can be used for covers, packing, etc.

[0032]

EXAMPLES The present invention will now be described by way of examples, which should not be construed as limiting the invention. The thermoplastic polyurethanes in Examples and Comparative Examples were evaluated by the following methods.

Appearance of extruded product: width of 10 m with a 30 mm extruder (L / D25) equipped with a film forming die.
A film having a thickness of 300 μm was prepared and the state of the unmelted material was observed.

(Evaluation Criteria) A: Almost no unmelted material is observed, surface condition is good B: Unmelted material is slightly observed, surface condition is good C: Unmelted material is often observed, surface condition is slightly defective D : Unmelted material is often seen and surface condition is poor

Mechanical strength: Using a test piece obtained by injection molding, hardness, tensile strength, elongation and modulus were measured according to JIS-K7311.

Flow starting point: Temperature rising method (Hold 120 using Shimadzu's high-performance flow tester CFT-500 type)
℃ × 10 minutes, heating rate 3 ℃ / min, die 1mmφ × 1m
ml, load 30 Kg).

Weather resistance: The test piece obtained by injection molding was measured for mechanical strength after irradiation for 500 hours with a sunshine weather orometer, and the retention of tensile strength was used for evaluation of weather resistance.

Heat resistance: The test piece obtained by injection molding was exposed in a gear oven at 120 ° C., and the mechanical strength was measured after 2 weeks, and the retention of tensile strength was used as the evaluation of heat resistance.

Example 1-1 2007 parts of lactone-modified polyhexamethylene carbonate polyol having a molecular weight of 2007 (Dainippon Ink prototype, 50% by weight of lactone), 1,6-hexanediol 2
After 36 parts and 0.9 part of dibutyltin dilaurate were mixed, 489 parts of hexamethylene diisocyanate was added, and the mixture was stirred and mixed at a high speed, cast into a vat, and reacted at 180 ° C. for 1 hour. After crushing this reaction product, it was pelletized by an extruder to obtain a thermoplastic polyurethane resin (Example 1-
1) was obtained. The above test was performed using this. The appearance of the extrusion molded product is shown in Table 1.

The abbreviations in each table below mean the following. HDI: Hexamethylene diisocyanate H ₁₂ MDI: 4,4'-dicyclohexylmethane diisocyanate 1,6HG: 1,6-hexanediol 1,4BG: 1,4-butanediol BHEB: Bishydroxyethoxybenzene CHDM: Cyclohexanedimethanol LC- PCD: Lactone modified polycarbonate polyol (Mw = 2007) Dainippon Ink and Chemicals Industrial prototype MPD / AA: 3 methyl 1,5 pentanediol adipate polyol (Mw = 1957) Dainippon Ink and Chemicals industrial prototype

Examples 1-2 to 4 and Comparative Examples 1-1 to 4 In the same manner as in Example 1-1, thermoplastic polyurethane resins as shown in Table 1 were obtained and extrusion molded in the same manner. The appearance of the product was evaluated, and the results are shown in Table 1.

[0042]

[Table 1] As shown in Table 1, it can be seen that the thermoplastic polyurethane resin using a polyol having 6 or more carbon atoms as a chain extender is excellent in extrusion molding appearance at any reaction equivalent ratio. Examples 2-1 to 4-2

[0043]

[Table 2] The results obtained by measuring the flow starting point, hardness, tensile strength, elongation, 100% modulus, heat resistance and weather resistance of the various polyurethane resins used in Examples 1 to 4 are shown in Table-
Shown in 3.

[0044]

[Table 3]

[0045]

INDUSTRIAL APPLICABILITY In the method for producing a thermoplastic polyurethane resin of the present invention, a polyol having 6 or more carbon atoms is used as a chain extender. Therefore, when a polyol having less than 6 carbon atoms is used, the extrusion molding cannot be obtained. A particularly remarkable effect is obtained in that a thermoplastic polyurethane resin capable of obtaining a molded article having an excellent appearance can be obtained from time to time.

Moreover, even in the continuous method, which requires precise control in which a change in the reaction equivalence ratio with time is unavoidable due to, for example, pressure fluctuation, as in the case of using a polyol having less than 6 carbon atoms, The desired thermoplastic polyurethane resin can now be obtained without the need for precise control.

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[Procedure amendment]

[Submission date] October 15, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 6

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

The inventors of the present invention have made diligent studies in view of the above situation, and as a chain extender,
It was found that a molded product having a better appearance can be obtained by using a polyol having 6 or more carbon atoms instead of the polyol having less than 6 carbon atoms, and has completed the present invention.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

A low molecular weight polyol having 6 or more carbon atoms and a polyol having less than 6 carbon atoms may be mixed and used. In this case, the proportion of the polyol having 6 or more carbon atoms is preferably 50 mol% or more.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

As the polycarbonate polyol, a lactone-modified polycarbonate polyol is preferable in that bleeding is less likely to occur in a molded article of the obtained thermoplastic polyurethane resin and the appearance of the molded article is better.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

The present invention is applicable to the continuous production of a thermoplastic polyurethane resin using a highly crystalline raw material such as a polycarbonate polyol as a polymer polyol, an aliphatic isocyanate and / or an alicyclic isocyanate as a linear aliphatic diisocyanate. It is particularly effective, and the effects of the invention are more likely to be exhibited.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

The production of the thermoplastic polyurethane resin of the present invention can be carried out by the usual production of thermoplastic polyurethane. For example, a polymer polyol (C) with excess isocyanate (A) in advance at a temperature of 120 ° C. or lower, preferably 100 ° C. or lower, is used as a prepolymer of a terminal isocyanate and a chain extender (B). Liquid (prepolymer method) or a method of measuring and mixing two liquids (one-shot method) of a polyol compound obtained by mixing a polymer polyol (C) and a chain extender (B) and an isocyanate (A), respectively, or The above raw materials are continuously weighed by a metering pump, vigorously mixed and stirred, and then poured onto a vat and further 80 to 200 ° C., preferably 120 to 1
It can be produced by a method of reacting at a temperature of 80 ° C. and then pulverizing.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

The abbreviations in each table below mean the following. HDI: hexamethylene diisocyanate 1,6HG: 1,6-hexanediol 1,4BG: 1,4-butanediol BHEB: bishydroxyethoxybenzene CHDM: cyclohexanedimethanol LC-PCD: lactone-modified polycarbonate polyol (Mw = 2007) large Nippon ink chemical industry prototype

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

Moreover, even in the continuous method in which the change of the reaction equivalence ratio with time is unavoidable due to the pressure change or the like like the case of using the polyol having less than 6 carbon atoms, it is desired without the need of precise control. The thermoplastic polyurethane resin of

Claims (7)

[Claims] 1. A method for producing a thermoplastic polyurethane resin, which comprises reacting an aliphatic isocyanate and / or an alicyclic isocyanate (A) with a chain extender (B) and a polymer polyol (C), wherein the chain extender ( A method for producing a thermoplastic polyurethane resin, wherein B) is a polyol having 6 or more carbon atoms. 2. The production method according to claim 1, wherein the production method of the thermoplastic polyurethane resin is a continuous production method. 3. The method according to claim 1, wherein the polymer polyol (C) is a polycarbonate polyol. 4. The method according to claim 1, wherein the isocyanate (A) is a linear aliphatic diisocyanate. 5. The method according to claim 1, wherein the chain extender (B) is 1,6-hexanediol. 6. A thermoplastic polyurethane resin is prepared so that the flow starting point is 125 ° C., the isocyanate (A),
Select the chain extender (B) and polymer polyol (C),
The production method according to claim 1, wherein they are reacted. 7. A molded article obtained by molding the thermoplastic polyurethane resin obtained by the production method according to claim 1.