JPH0570570B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a polyurethane film. More specifically, the present invention relates to a simplified method for producing a polyurethane film by integrating the urethanization reaction/film formation steps.

[Conventional technology and problems]

Generally, polyurethane films have high strength, excellent abrasion resistance, and moisture permeability, and are therefore used in the fields of clothing, sanitary materials, and various elastic films. However, the conventional method for producing polyurethane film is to synthesize thermoplastic polyurethane from polyol and polyisocyanate, pelletize it, and then form it into a film by extrusion molding. This makes the manufacturing process complicated and causes high costs. In addition, since the conventional method uses a method of melt extrusion molding polyurethane, the polyurethane used is limited to thermoplastic types, and it is not possible to make thermosetting polyurethane films with higher strength and excellent abrasion resistance. It has the disadvantage that it is not.

[Means for solving problems]

As a result of extensive research aimed at solving the above-mentioned drawbacks, it was discovered that the urethanization reaction/film formation steps could be integrated, and the present invention was achieved.

That is, in the present invention, a polyol component and a polyisocyanate compound, which are raw materials for polyurethane, are mixed and stirred, the mixture is injected into a twin-screw extruder, polymerized, and the film is passed through a die attached to the twin-screw extruder via a metering pump. The present invention provides a method for producing a polyurethane film characterized by the following.

In the method of the present invention, the polyol component has a number average molecular weight of 500 to 5000 and an average number of functional groups (f) of 2.
It is necessary to use high molecular weight polyols with ≦f<4 and those containing chain extenders and/or crosslinkers. When the molecular weight is less than 500, the viscosity is too low and operability is poor. Moreover, the final physical properties of the obtained polyurethane are also not good. On the other hand, when the molecular weight exceeds 5000, the viscosity is too high and mixing becomes difficult. The average number of functional groups (f) is f
= 1, it becomes a monol and does not polymerize, while f≧5
However, it is not preferable because it is too polyfunctional and the viscosity of the polymer increases and the physical properties deteriorate.

Conventionally known components can be used for producing the polyurethane according to the present invention. Examples of high molecular weight polyols include polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polyoxytetramethylene glycol, and polyether type polyols such as alkylene oxide adducts such as bisphenol A and glycerin with ethylene oxide and propylene oxide; Dibasic acids such as adipic acid, phthalic anhydride, isophthalic acid, maleic acid, fumaric acid, succinic acid and ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, Examples include polyester type polyols obtained by polycondensation reaction with glycols such as trimethylolpropane, polycaprolactone diol, polycarbonate diol, and the like.

The number average molecular weight of these high molecular weight polyols is
The range is from 500 to 5000, particularly preferably from 1000 to 3000.

Further, as polyisocyanate compounds, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, 1,4-cyclohexane diisocyanate , isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and the like.

These polyols and polyisocyanate compounds may be reacted by any of the one-shot method, pseudo-prepolymer method, and prepolymer method employed in conventional polyurethane production methods, but the pseudo-prepolymer method or polypolymer method may be used. The properties of the product obtained will be better when used.

Furthermore, as a chain extender, ethylene glycol,
Mention may be made of low molecular weight diols such as 1,4-butanediol, diethylene glycol, 1,6-hexanediol, neopentyl glycol and N-methyldiethanolamine, and diamines such as ethylenediamine, hexamethylenediamine and isophoronediamine. Preferably, low molecular weight diols are used.

Furthermore, trimethylolpropane, triethanolamine, glycerin, and ethylene oxide and propylene oxide adducts thereof may be added as polyfunctional components if necessary. In the production of the polyurethane of the present invention, the OH group/NCO group equivalent ratio is preferably in the range of 0.95 to 1.05, preferably in the range of 0.98 to 1.02, in view of the physical properties of the polyurethane produced.

Furthermore, the present invention is not limited only to polyurethane, and it is also possible to add various thermoplastic resins and/or inorganic and organic fillers.

The twin screw extruder used in the present invention is L/D
(length/diameter ratio) must be in the range of 30 to 70. Moreover, it is preferable that the rotation speed is 30 to 400 rpm. Examples of commercially available twin screw extruders include
PCM-45 (Ikegai Iron Works Co., Ltd.), ZSK-57 (West German Werner
), TEM-50A (Toshiba Machine Co., Ltd.), BT-40-S (Plastic Engineering Research Institute), TEX44-30AW-2V
(Japan Steel Works) etc. In the present invention, a metering pump is installed between the twin-screw extruder and the die in order to improve the metering feedability in film production. By using this metering pump, the process from reaction to film formation can be integrated, and there is no need to re-melt the polyurethane, so there is less risk of side reactions occurring, and the quality of polyurethane is highly stable. It has remarkable effects such as improving sexual performance. Further, a single screw extruder may be provided between the die and the twin screw extruder. As the die, a T-die is preferable because of the simplicity of the device.

In view of the reaction time during polyurethane synthesis, the barrel temperature of the twin-screw extruder is preferably set at 150° to 250°C.

Furthermore, in order to prevent the finished polyurethane film from blocking together, a release paper or a finely powdered mold release agent such as aloesil may be used.

As described above, the method of the present invention makes it possible to simultaneously polymerize and form a film from polyurethane raw materials instead of forming a film by melt extrusion of thermoplastic polyurethane. It has become possible to manufacture a simplified and thermosetting type polyurethane film.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

Production examples of the polyol component and isocyanate compound used in Examples 1 to 4 are shown below.

Production example 1 (A) 15 kg of polybutylene adipate with a number average molecular weight of 1000, 30 kg of polybutylene adipate with a number average molecular weight of 2000, and 4.24 kg of 1,4-butanediol
Kg was put into a 50 ml reaction vessel and stirred and mixed at 80°C in a nitrogen stream. The resulting polyol mixture had a hydroxyl value of 175.7 KOHmg/g.

(B) 24.8 kg of diphenylmethane diisocyanate, 9 kg of polybutylene adipate with a number average molecular weight of 1000, and 18 kg of polybutylene adipate with a number average molecular weight of 2000 were placed in a 50-liter reaction vessel and stirred at 70°C in a nitrogen stream for 3 hours. A prepolymer was obtained by the reaction. The free isocyanate groups of the obtained prepolymer was 13.2%.

Production example 2 (A) 42 kg of polyoxytetramethylene glycol with a number average molecular weight of 2000, 1,4-butanediol
5.05Kg and 0.83Kg of trimethylolpropane 50
The mixture was added to a reaction vessel and stirred and mixed at 80°C in a nitrogen stream. The resulting polyol mixture had a hydroxyl value of 202.5 KOHmg/g.

(B) 25Kg of diphenylmethane diisocyanate and 23.8Kg of polyoxytetramethylene glycol with a number average molecular weight of 2000 were placed in a 50mm reactor and reacted with stirring at 70℃ for 3 hours in a nitrogen stream to obtain a prepolymer. . The free isocyanate groups of the obtained prepolymer was 15.2%.

Production Example 3 (A) 31 kg of polyoxytetramethylene glycol with a number average molecular weight of 1000 and 18.1 kg of N-methyldiethanolamine were placed in a 50-liter reaction vessel and heated in a nitrogen stream.
The mixture was stirred and mixed at 80°C. The resulting polyol mixture had a hydroxyl value of 414.4 KOHmg/g.

(B) 43 kg of isophorone diisocyanate and 7.09 kg of polyoxytetramethylene glycol with a number average molecular weight of 1000 were charged into a 50-liter reaction vessel and heated in a nitrogen stream.
A prepolymer was obtained by reacting at 80°C for 5 hours with stirring. The free isocyanate groups of the obtained prepolymer was 31.3%.

Production example 4 (A) 50 kg of polyoxytetramethylene glycol with a number average molecular weight of 1000, 11.8 kg of N-methyldiethanolamine, and 43 kg of triethanolamine
The mixture was added to a reaction vessel and stirred and mixed at 80°C in a nitrogen stream. The hydroxyl value of the obtained polyol mixture is
It was 399.7KOHmg/g.

(B) 47.0 kg of methylene bis(cyclohexyl isocyanate) and 2.58 kg of polyoxytetramethylene glycol with a number average molecular weight of 1000 were placed in a 50-liter reaction vessel and reacted with stirring at 80°C for 5 hours in a nitrogen stream to obtain a prepolymer. Ta. The free isocyanate groups of the obtained prepolymer were 30.0%
It was hot.

Examples 1 to 4 were prepared using the above polyol component and polyisocyanate compound, and by the manufacturing process shown in Figure 1.
Polyurethane film was manufactured in the same way. In FIG. 1, 1 is a polyol tank, 2 is a prepolymer tank, and 3 is a quantitative mixer. Polymerization is carried out through a twin-screw extruder (No. 4), followed by a metering feed pump (5) and a T-die (6) to form a film. 7 is a pressure roll, 8 is a cooling roll,
The film 9 is wound onto a take-up roll 10.

Example 1 The polyol mixture obtained in Production Example 1A and the prepolymer obtained in Production Example 1B were sent to a mixing device at a rate of 150 g per minute through a gear wheel type pump, and in a uniformly mixed state, It is injected into the inlet tube of a twin screw extruder (L/D=45) with two shafts rotating at the same interval at 200 revolutions per minute.

The barrel temperature of the extruder was 160°C at the inlet and 200°C at the outlet.

T connected to the extruder outlet via a metering pump
- The film produced through the die was stretched using a biaxial stretching device to form a film with a thickness of 50 μm.

Example 2 A film was produced in the same manner as in Example 1 using the products obtained from Production Example 2A and Production Example 2BB.

The film had a thickness of 50 μm, a tensile strength of 400 Kg/cm ² and a tear deformation of 350%. Furthermore, the obtained film was thermosetting and insoluble in solvents such as dimethylformamide.

Example 3 A film was produced in the same manner as in Example 1 using the products obtained from Production Example 3A and Production Example 3B.

The film had a thickness of 50 μm, a tensile strength of 350 Kg/cm ² and a tear deformation of 600%.

Example 4 A film was produced in the same manner as in Example 1 using the products obtained from Production Example 4A and Production Example 4B.

The film had a thickness of 50 μm, a tensile strength of 300 Kg/cm ² and a tear deformation of 350%. Furthermore, the obtained film was thermosetting and insoluble in solvents such as dimethylformamide.

〔Effect of the invention〕

As is clear from the examples and manufacturing schematic diagrams, the manufacturing process is streamlined and it becomes possible to manufacture not only conventional thermoplastic polyurethane but also thermosetting polyurethane films, and its industrial value is extremely large.

According to the method of the present invention, polyurethane films with a high degree of crosslinking can be easily and continuously produced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the manufacturing process of the present invention. 1... Polyol tank, 2... Prepolymer tank, 4... Twin screw extruder, 5... Metering feed pump, 6... T-die.

Claims (1)

[Claims] 1 The polyol component and the polyisocyanate compound, which are raw materials for polyurethane, are polymerized through a twin-screw extruder, and then formed into a film through a die connected via a metering pump, so that the polyol component has a number average molecular weight of 500 to 5000. , containing a high molecular weight polyol with an average number of functional groups (f) of 2≦f<4, a chain extender and/or a crosslinking agent, and a twin screw extruder having an L/D (length/diameter ratio) of 30 to 70. A method for producing a polyurethane film.