JPS62292412A - Continuous manufacture of polyurethane film - Google Patents

Abstract

PURPOSE:To obtain a polyurethane film with the thickness of 25mum or less homogeneously and continuously without unevenness in the thickness of the film by a method wherein solvent solution, in which the viscosity of polyurethane polymer and solid content are specified, is coated on parting paper by employing a comma-coating device. CONSTITUTION:The solvent solution of polyurethane polymer is coated on a parting paper by employing a comma-coating device 3, subsequently, the parting paper is passed through a drying oven 5 to dry the solvent, thereafter, the formed film is separated from the parting paper whereby a polyurethane film with the thickness of 25mum or less or preferably 20mum or less is manufactured continuously. The solvent solution 9 of polyurethane polymer is diluted by diluting agent such as DMF, for example, until the content of solid constituents becomes 15-80% and it is necessary to show the viscosity of about 2,000-3,000cps/20 deg.C upon coating. When the viscosity is up to 2,000cps, the leakage or repelling of side polymer is caused and the thickness of the film is not uniformized while the control of the thickness becomes difficult and the formation of a thin film becomes impossible when the viscosity exceeds 3,000cps.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for continuously producing a polyurethane film.

(Prior art) Conventionally, general film forming methods include, for example, the T-die method,
There are stretching methods, inflation methods, calendar methods, casting methods (solution casting methods), etc.

In addition, among the above urethane film forming methods, T
The die method, its stretching method, and the calender method have been used, but with these methods, it is impossible to form a uniform film with a thickness of 25 μm or less and without anisotropy. That is, it has been difficult to eliminate the anisotropy because it is difficult to stretch uniformly both vertically and horizontally.

(Problems to be Solved by the Invention) An object of the present invention is to provide a method for continuously forming a polyurethane film having a thickness of 25 μm or less.

Another object of the present invention is to provide a method for forming a homogeneous urethane film with a thickness accuracy of ±1 μm, no foreign matter, no dels, no pinholes, and no anisotropy.

(Means for Solving the Problems) The present invention uses a comma coating device to reduce the viscosity of polyurethane polymer from 2000 to 30000 cps/20.
℃, a solvent solution with a solid content of 15 to 80% is applied onto a release paper, and then passed through a drying oven to dry the solvent.
Peel the formed film from the release paper to a film thickness of 25 μm.
The present invention relates to the following method for continuously producing a polyurethane film.

In the present invention, various types of polyurethane polymers can be used, and can be obtained, for example, by reacting a polyol, a polyisocyanate, and, if necessary, a chain extender.

In the present invention, various polyester polyols, polyether polyols, and other polyols can be used as the polyol. Examples of polyester polyols include aliphatic dicarboxylic acids having 4 to 20 carbon atoms such as divic acid, superic acid, sebacic acid, and brassylic acid, terephthalic acid, and isophthalic acid as acid components, and ethylene glycol, propylene glycol, and neopentyl glycol. , aliphatic diols having 1 to 6 carbon atoms such as hexamethylene glycol, ether glycols such as diethylene glycol and dipropylene glycol, and spiroglycol M
, polyester polyol or polycaprolactone polyol containing N-furkyl dialkanolamine such as N-methyljetanolamine as a polyol component, specific examples include polyethylene adipate polyol, polybutylene adipate polyol, polyethylene bronchide polyol, etc. 7-dibate polyols such as birenanobate polyol, terephthalic acid polyols (e.g., Toyobo Co., Ltd., product names Vylon RUX, Vylon RV-20OL), polycaprolactone polyols (e.g., Daicel Chemical, product names Plaxel 212, Plaxel 220) ) etc. can be exemplified.

Specific examples of polyether polyols include polyoxyethylene polyol, polyoxypropylene polyol, polyoxytetramethylene polyol, and the like.

In addition, other polyols include polycarbonate polyols (e.g., West Germany, Bayer AG, trade name Desmoreen 2020E), polybutadiene polyols (e.g., Japan 1Tachi, trade names G-1000, G-2000, G-300).
0, Idemitsu Petrochemical, trade name PolybdR-45HT
), polypentadiene polyol, castor oil polyol, and the like. These polyols can be used alone or in combination of two or more.

Examples of the polyisocyanate used in the present invention include various polyisocyanates, such as diphenylmethanoisocyanate (MDI) and lylene diisocyanate (TD).
I),) Lysine diisocyanate) (TODI), Xylylene diisocyanate (MDI), Na7 ethylene diisocyanate (NDI), Inphorone diisocyanate) (I
PD IL to-N Sameethylene diisocyanate (HD
I), nocyclohexylmethane diisocyanate (HM
DI), diisocyanates such as lylene diisocyanate (LDI), triphenylmethane triincyanate,
Polymethylene polyphenylisocyanate (PAPI)
, carposiimide-modified MDI, and other polyisocyanates, and these can be used alone or in combination of two or more. It is also possible to use one in which a part of these incyanates is blocked with a blocking agent.

In addition, all known chain extenders can be used, such as ethylene glycol, 1,4-butanediol, neopentyl glycol, etc.
, 4-methylenebis(2-chloroaniline), isophoronediamine, piperazine, diamines such as ethylenediamine, and amino alcohols such as N-methylethanolamine and monoethanolamine.

Specific examples of the polyurethane used in the present invention are shown by trade names, such as Crisbon NB-6313, 5006 (
Examples include Dainippon Ink Chemical Co., Ltd.), Niboran 5121 (Nippon Polyurethane Co., Ltd.), and the like.

The present invention uses a comma coating device to apply a solvent solution of a polyurethane polymer onto a release paper, then passes it through a drying oven to dry the solvent, and then peels the formed film from the release paper. , a polyurethane film having a thickness of 25μ or less, preferably 20μ or less is produced. The film peeled off from the release paper may be wound up on a take-up roll or may not be wound up.

In the present invention, the solvent solution of the polyurethane polymer is diluted with a diluent such as DMF, methyl ethyl ketone (MEK), toluene, or a chlorinated solvent to a solid content of 15 to 80%, and is coated at approximately 2,000 to 30,000 cps.
It is necessary to exhibit a viscosity of /20°C, and in this case, silicone surfactants, weathering agents, pigments, and other additives may be added as appropriate. Viscosity is 20
If it is less than 30,000 cps, the side polymer may leak or repel and the thickness will not be uniform, and if it exceeds 30,000 cps, it will be difficult to control the thickness and it will be impossible to form a thin film. Further, if the solid content is less than 15%, the clearance becomes large, resulting in uneven thickness, foaming, insufficient drying, etc. Moreover, if it exceeds 80%, it becomes difficult to control the thickness to 25 μm or less. Polyethylene terephthalate (PET) is used as a release paper for applying the solvent solution of the above polyurethane polymer for coating.
Films, polyethylene laminate paper, etc. are suitable. A comma coater can be used as a continuous coating device.

FIG. 1 shows an outline of the coating process using the feed muffer of the present invention. In the figure, 1. release paper feeder; 2. Back roll, 3, comma coater, 4. Suction type feed belt, 5. Drying oven, 6. Cooling drum, 7. Suction type tension roll, 8. film winder, 9,
Solvent solution of polyurethane polymer, 10. Liquid feed pump, 11. Release paper roll ') Ill.

Depending on the application, the film can be wound together with the release paper without using the release paper winding block (11)! (8) It can be wound up. In this case, it is also possible to further process the film into a film of desired dimensions using Ike's well-known glue wine goose slitting machine or the like.

Drying of the coating film is approximately 0.5 at approximately 70 to 150'C.
It is preferable to carry out the reaction for about 2 minutes, and the thickness of the formed film needs to be 25 μm or less, more preferably 20 μm or less.

(Examples) Next, the present invention will be specifically explained based on Examples. still,
Parts or % simply refer to parts or % by weight.

Example 1 Using Plaxel 220 (2000 parts), 60 parts of ethylene glycol, MDI (505 parts) and (/DMF/)luene (4/6) so that the solid content was 30%, 8
The reaction was carried out at 0°C for 3 hours. Toluene was further added to the obtained polyurethane polymer solution to adjust the solid content to 25%,
Furthermore, 1 part of silicon was added as an additive. This solution had a viscosity of 5600 cps/20°C, and the polyurethane polymer solution was coated on a 50μ thick, 3000++ PET film coated with a release agent on one side using a comma coating machine and coated with a 200 mesh wire mesh. After coating with a clearance of 70 μm (dry film thickness, 15 μm) and then passing through a drying oven at 135-140° C. for 40 seconds at a rate of 20 [11 parts], the resulting polyurethane film was peeled off from the PET film.

(Effects of the Invention) According to the present invention, a thin polyurethane film having a thickness of 25 μm or less can be obtained without variation in thickness. In addition, the obtained film is a glossy transparent film,
In particular, it is a high-quality thin film with no foreign matter, gel, or pinholes, and no anisotropy at all, and it can be formed continuously.

[Brief explanation of the drawing]

FIG. 1 shows a schematic diagram of a comma coating apparatus suitable for producing the polyurethane film of the present invention. (Above) Patent applicant Toyo Rubber Industries Co., Ltd. Agent Patent attorney 1) Iwao Mura
1 figure

Claims (1)

[Claims] (1) Using a comma coating device, apply a solvent solution of a polyurethane polymer with a viscosity of 2,000 to 30,000 cps/20°C and a solid content of 15 to 80% onto release paper, and then pass it through a drying oven to dry the solvent. A method of continuously producing a polyurethane film having a thickness of 25 μm or less by peeling the formed film from a release paper.