JP2005307182A - Heat-resistant polyurethane film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new heat-resistant polyurethane film capable of steadfastly maintaining excellent heat resistance, without being molten, nor thermally deteriorated, even when the film is exposed to a temperature at which a hot-melt layer is molten in case being laminated with the hot-melt layer, and capable of exhibiting excellent weather resistance, water resistance, and chemical resistance as well. <P>SOLUTION: This heat-resistant polyurethane film is formed by using a polyurethane resin composition which contains a polyurethane resin (A) obtained from a polyol (a) having two or more groups reactive with isocyanate groups and a molecular weight of 60-140, a polyol (b) having two or more hydroxy groups and a number-average molecular weight of 140-4000, and an alicyclic and/or an aromatic diisocyanate (c), silica (B) formed by a wet process, an ultraviolet absorber (C), and a polyisocyanate (D) having three or more isocyanate groups as constituents, wherein the diisocyanate (c) is contained in the polyurethane resin (A) in an amount 10-40 mass % based on a solid content of the resin (A) and the polyisocyanate (D) is contained in an amount of 5-30 pts.wt. based on 100 pts.wt. of the solid content of the polyurethane resin (A). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat resistant polyurethane film. More specifically, a film made of a specific polyurethane resin composition, for example, when the film is multi-layered with a hot melt layer, the film melts even under temperature conditions at which the hot melt layer can melt. Alternatively, the present invention relates to a novel heat-resistant polyurethane film that maintains excellent heat resistance without thermal deterioration and also exhibits excellent weather resistance, water resistance, and chemical resistance.

  Conventionally, polyurethane resins have been used in a wide range of applications such as adhesive materials, molding materials, synthetic leather, artificial leather, surface treatment agents, paints, films, and sheets because they have excellent properties such as mechanical strength and elasticity. It was. In particular, when attention is focused on film applications, it has been mainly used for bonding processing of fibers, sheets, and the like because it has a good feel and a soft texture due to the elasticity unique to polyurethane resins.

However, even if the polyurethane film obtained by the conventional production method has good heat resistance, it is inferior in weather resistance, and therefore yellowed in a short time with time, and has poor practicality.
On the other hand, in the conventional polyurethane film, even if the weather resistance is good, the heat resistance is inferior. For example, the temperature at which the hot melt layer is melted when multilayered with the hot melt layer (usually 130 to 180 ° C. However, it has a problem of melting or breaking.
Furthermore, the polyurethane film as described above has a problem that it is inferior in water resistance and chemical resistance.

In order to improve such a problem, for example, a thermoplastic polyurethane resin, a polyvinyl chloride resin, a plasticizer, fine powder synthetic silica, and other additives are mixed, dissolved in a solvent to obtain a uniform solution or dispersion, Alternatively, it is kneaded under heating to form a uniform composition, formed into a film, heated in boiling water or steam, and then rapidly cooled, and a method for producing the film (Patent Document 1). Has been proposed.
However, such a film made of a thermoplastic polyurethane resin is still unsatisfactory in terms of heat resistance, chemical resistance, water resistance and the like, and is not satisfactory in practice.
As described above, the actual situation is that a polyurethane film having excellent performance such as heat resistance, weather resistance, water resistance, and chemical resistance has not been developed yet.

JP-A-5-239235

  It is an object of the present invention to maintain excellent heat resistance without melting or thermal deterioration even under temperature conditions where the hot melt layer can be melted when it is formed into a film and multilayered with the hot melt layer. Another object of the present invention is to provide a novel heat-resistant polyurethane film that exhibits excellent weather resistance, water resistance, and chemical resistance.

  As a result of intensive studies to solve the above problems, the present inventors have found that a specific polyurethane resin (A), a wet process silica (B), an ultraviolet absorber (C), and an isocyanate group in the molecule. A polyurethane resin composition comprising three or more polyisocyanate (D) as an essential constituent component provides a heat resistant polyurethane film having excellent characteristics such as excellent heat resistance, weather resistance, water resistance, and chemical resistance. As a result, the present invention has been completed.

  That is, the present invention relates to a polyol (a) having two or more groups having reactivity with isocyanate groups in the molecule and a molecular weight in the range of 60 to 140, and a number average molecular weight having two or more hydroxyl groups in the molecule. A polyol (b) in the range of 140 to 4000, at least one polyurethane resin (A) obtained from an alicyclic diisocyanate and / or an aromatic diisocyanate (c), a wet process silica (B), and an ultraviolet absorber. (C) and a polyisocyanate (D) having three or more isocyanate groups in the molecule are essential constituents, and the content of diisocyanate constituent units in the solid content of the polyurethane resin (A) is 10 to 40% by mass. And the polyisocyanate (D) is isophorone diisocyanate, cyclohexane diisocyanate, dicyclohexylmedium. Trimethylolpropane adducts obtained from alicyclic diisocyanates such as diisocyanates, and diisocyanates in which an isocyanate group is bonded via an methylene group to an aromatic ring such as xylylene diisocyanate and tetramethylxylylene diisocyanate, Or at least one selected from the group consisting of isocyanurates, wherein the content of the polyisocyanate (D) is in the range of 5 to 30 parts with respect to 100 parts of the solid content of the polyurethane resin (A). A heat resistant polyurethane film characterized by using a resin composition is provided.

The heat-resistant polyurethane film of the present invention has excellent characteristics such as heat resistance, weather resistance, water resistance, and chemical resistance.For example, deterioration due to heat history is also caused during molding processing such as film formation. Very few, stable continuous production is possible, and productivity is excellent.
Further, when the heat-resistant polyurethane film of the present invention is multilayered with a hot melt layer, the heat-resistant polyurethane film maintains excellent heat resistance without being melted or thermally deteriorated even under a temperature condition at which the hot melt layer can be melted. And excellent weather resistance, water resistance, and chemical resistance.

The matters necessary for carrying out the present invention are described below.
The heat-resistant polyurethane film of the present invention comprises at least one polyurethane resin (A), a wet process silica (B), an ultraviolet absorber (C), and a polyisocyanate (D) having three or more isocyanate groups in the molecule. Is a polyurethane resin composition comprising as an essential component.

First, the essential components of the polyurethane resin composition used in the production of the heat-resistant polyurethane film of the present invention will be described below.
The polyurethane resin (A) used in the present invention is a polyol (a) having two or more groups having reactivity with isocyanate groups in the molecule and a molecular weight in the range of 60 to 140, and two hydroxyl groups in the molecule. The polyol (b) having a number average molecular weight in the range of 140 to 4000 and an alicyclic diisocyanate and / or an aromatic diisocyanate (c) can be obtained by a conventionally known reaction method, and particularly limited. do not do.

  As an isocyanate group-reactive compound used as a raw material for synthesizing the polyurethane resin (A) used in the present invention, a polyol having a molecular weight of 60 to 140 having two or more groups having reactivity with an isocyanate group in the molecule ( a) and a polyol (b) having two or more hydroxyl groups in the molecule and having a number average molecular weight of 140 to 4000 as an essential component, and at least one selected from alkanolamines and polyamines depending on the purpose You may use together. By using the polyol (a) and the polyol (b) in combination, an excellent performance polyurethane film having both flexibility and toughness can be obtained.

  Polyol (a), which is one of the raw materials for synthesizing the polyurethane resin (A), having two or more groups reactive with isocyanate groups in the molecule and having a molecular weight in the range of 60 to 140, and alkanolamine, or Examples of the polyamine include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, cyclohexane-1 , 4-dimethanol, glycerin, trimethylo Polyols such as propane, trimethylolethane, hexanetriol, pentaerythritol, sorbitol, methylglycoside, or monoethanolamine, diethanolamine, triethanolamine, N-methylmonoethanolamine, N-butylmonoethanolamine, N-methyldiethanolamine, Alkanolamines such as N-butyldiethanolamine, ethylenediamine, 1,3-propylenediamine, 1,2-propylenediamine, hexamethylenediamine, hydrazine, piperazine, N, N′-diaminopiperazine, 2-methylpiperazine, 4,4 '-Diaminodicyclohexylmethane, isophoronediamine, diaminobenzene, diphenylmethanediamine, methylenebisdichloroaniline, etc. Such as one or more mixtures of Riamin thereof. Among these compounds, glycols are preferable, linear glycols are more preferable, and 1,4-butanediol is particularly preferable.

  Polyol (a), which is one of the raw materials for synthesizing the polyurethane resin (A), having two or more groups having reactivity with isocyanate groups in the molecule and having a molecular weight in the range of 60 to 140, depending on the purpose The content of the polyurethane resin (A) in the solid content of 100 parts with at least one selected from the selected alkanolamine and polyamine is preferably in the range of 1 to 15 parts. If the polyurethane resin (A) contains the polyol (a) in such a range, a polyurethane film having excellent toughness and heat resistance can be obtained.

  Examples of the polyol (b), which is one of the raw materials for synthesizing the polyurethane resin (A), having two or more hydroxyl groups in the molecule and having a number average molecular weight in the range of 140 to 4000, include, for example, polyester polyols and polyethers. Examples thereof include polyols, polyester ether polyols, and mixtures thereof. These may be used alone or in combination of two or more.

Examples of the polyester polyol include, but are not limited to, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl- 1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1, One or more polyhydric alcohols such as 4-diol, cyclohexane-1,4-dimethanol, glycerin, trimethylolpropane, trimethylolethane, hexanetriol, pentaerythritol, sorbitol, methylglycoside, Succinic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, glutaric anhydride, maleic acid, Examples thereof include polybasic acids such as maleic anhydride and hexahydroisophthalic acid, lower alkyl esters such as methyl ester compounds, and condensates with one or more of acid anhydrides.
Moreover, ring-opening polymers such as γ-butyrolactone and ε-caprolactone using the polyol as an initiator, and poly (hexamethylene carbonate) diol are also included.

  Although it does not specifically limit as said polyether polyol, For example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, etc. which use the 1 type (s) or 2 or more types of the said polyol and polyamine as an initiator individually or 2 types or more And a ring-opening polymer.

  Although it does not specifically limit as said polyester ether polyol, For example, the copolymer of the polyol chosen from the 1 type (s) or 2 or more types of the said polyester polyol and polyether polyol, etc. are mentioned.

  The solid content 100 of the polyurethane resin (A), which is one of the synthetic raw materials for the polyurethane resin (A), is the polyol (b) having two or more hydroxyl groups in the molecule and having a number average molecular weight in the range of 140 to 4000. The content in the part is preferably in the range of 40 to 80 parts. When the polyurethane resin (A) contains the polyol (b) in such a range, a film material having excellent flexibility can be obtained.

  The alicyclic diisocyanate and / or aromatic diisocyanate (c), which is one of the raw materials for synthesizing the polyurethane resin (A), includes, for example, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, phenylene diisocyanate, lysine diisocyanate and the like. An isocyanate group is bonded to an aromatic diisocyanate, or an alicyclic diisocyanate such as cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, or an aromatic ring such as xylylene diisocyanate, tetramethylxylylene diisocyanate via a methylene group. Diisocyanates may be used, and one or a mixture of two or more of these may be used.

  The content of the diisocyanate structural unit in the solid content of the polyurethane resin (A) is preferably in the range of 10 to 40% by mass. If the said polyurethane resin (A) has the said diisocyanate structural unit in this range, the film material which has the outstanding toughness and heat resistance can be obtained.

It is preferable that a bisphenol A-alkylene oxide adduct is bonded in the molecule of the polyol (a) and / or polyol (b), which is a raw material for the synthesis of the polyurethane resin (A). Examples of the oxide adduct include n-mol adducts of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and tetramethylene oxide of bisphenol A (where n is a number exceeding 0). It is done.
Among these bisphenol A-alkylene oxide adducts, an ethylene oxide 2 mol adduct of bisphenol A is more preferable because it can further improve characteristics such as heat resistance.

  The content of the bisphenol A-alkylene oxide adduct in 100 parts of the polyurethane resin (A) is preferably in the range of 1 to 20 parts. If the bisphenol A-alkylene oxide adduct is bonded under such conditions, the resulting heat-resistant polyurethane film is multilayered with, for example, a hot melt layer, even under temperature conditions where the hot melt layer can melt. The film can maintain excellent heat resistance without melting or heat deterioration, and can also exhibit excellent weather resistance.

The polyurethane resin (A) has two or more groups having reactivity with isocyanate groups in the molecule, a polyol (a) having a molecular weight in the range of 60 to 140, and two or more hydroxyl groups in the molecule. It was obtained from polyol (b) having an average molecular weight in the range of 140 to 4000 and alicyclic diisocyanate and / or aromatic diisocyanate (c), and the content of the diisocyanate (c) was in the range of 10 to 40% by mass. These compounds can be reacted with the raw material by a known and conventional method, and as the reaction method, for example, various methods such as a solution reaction, a non-aqueous dispersion reaction, and an aqueous dispersion reaction can be adopted, and there is no particular limitation. However, among these, the solution reaction is preferable because the reaction can be easily controlled.
As the method of the solution reaction, for example, the polyol (b) is diluted with a solvent that does not inhibit the reaction, and then the polyol (a) is used in combination with at least one selected from alkanolamine and polyamine depending on the purpose. , A method of adding a isocyanate and reacting under appropriate reaction conditions (for example, reaction at 80 ° C. for 3 hours) to obtain a solution of the polyurethane resin (A), but is particularly limited thereto. is not.

  In addition to the polyurethane resin (A) that is the main component of the polyurethane resin composition used in the heat-resistant polyurethane film of the present invention, other resins that can be used are particularly limited as long as they do not impair the object of the present invention. For example, an acrylic resin, a polyester resin, a polyamide resin, an ethylene-vinyl acetate resin (EVA), a rosin ester, and the like may be used. These may be used alone or in combination of two or more.

The solvent used in producing the polyurethane resin (A) is not particularly limited as long as it does not inhibit the reaction. Examples thereof include esters such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate, acetone. , Ketones such as methyl ethyl ketone, methyl butyl ketone and cyclohexanone, ether esters such as methyl cellosolve acetate and butyl cellosolve acetate, aromatic hydrocarbon solvents such as toluene and xylene, and amides such as dimethylformamide and dimethylacetamide These may be used alone or in combination of two or more.
Moreover, the usage-amount of the solvent at the time of manufacturing a polyurethane resin (A) will not be specifically limited if it is a range which does not inhibit reaction.

Next, the wet process silica (B), which is an essential component of the polyurethane resin composition used in the heat resistant polyurethane film of the present invention, will be described below.
In general, synthetic silica is classified into wet process silica and dry process silica.
Wet process silica is a mixture of sodium silicate and sulfuric acid to produce a silicate sol. There are two types of wet process silica. One is the one in which primary particles of silicate sol are formed, then a three-dimensional secondary aggregate is formed and gelled, and this is pulverized. The average particle size is usually in the range of 2-5 μm. The other is a silicate sol secondary aggregate that has stopped growing and settled, and is called “precipitated silica” and has an average particle size of 0.1 μm or less. On the other hand, dry process silica is produced by combustion hydrolysis in the air layer, and has an average particle size of 0.1 μm or less.

  As the silica used in the heat-resistant polyurethane film of the present invention, wet method silica (B) is preferable, and gel method silica having an average particle diameter in the range of 2 to 5 μm is more preferable. If the average particle diameter of the wet process silica (B) is within the range, the heat-resistant polyurethane film of the present invention exhibits an excellent anti-blocking effect in the winding process, and is extremely effective in preventing troubles in the production process. is there.

  The content of the wet process silica (B) is preferably in the range of 5 to 30 parts, more preferably in the range of 7 to 20 parts with respect to 100 parts of the polyurethane resin (A). If the heat-resistant polyurethane film contains the wet process silica (B) in such a range, the film has an excellent effect in preventing blocking at the time of winding the film, and the productivity of the film is improved. A polyurethane film can be obtained.

Next, the ultraviolet absorbent (C), which is an essential component of the polyurethane resin composition used for the heat resistant polyurethane film of the present invention, will be described below.
Although it does not specifically limit as an ultraviolet absorber (C) used for the heat resistant polyurethane film of this invention, For example, benzotriazole represented by methylhydroxyphenyl benzotriazole, butylmethyl hydroxyphenyl benzotriazole, dibutyl hydroxyphenyl benzotriazole, etc. And hindered amine compounds represented by bis (tetramethylpiperidyl) sebacate, bis (pentamethylpiperidyl) sebacate, and the like.

  The content of the ultraviolet absorber (C) is preferably in the range of 0.1 to 7 parts with respect to 100 parts of the polyurethane resin (A). If the heat-resistant polyurethane film contains the ultraviolet absorber (C) in such a range, for example, when used as a multilayer film, a film material having no discoloration and high quality and high added value can be obtained.

  Furthermore, the polyisocyanate (D) having 3 or more isocyanate groups in the molecule, which is an essential component of the polyurethane resin composition used in the heat resistant polyurethane film of the present invention, is isophorone diisocyanate, cyclohexane diisocyanate, dicyclohexylmethane diisocyanate. Trimethylolpropane adducts, burettes, or isocyanates obtained from alicyclic diisocyanates such as, and diisocyanates in which an isocyanate group is bonded via an methylene group to an aromatic ring such as xylylene diisocyanate and tetramethyl xylylene diisocyanate At least one selected from the group consisting of nurate is preferable, and among these polyisocyanates, performance such as heat resistance, weather resistance, water resistance, and chemical resistance is further improved. In view possible, trimethylolpropane adduct of xylylene diisocyanate (XDI-TMP) is more preferable.

  The content of the polyisocyanate (D) is preferably in the range of 5 to 30 parts with respect to 100 parts of the polyurethane resin (A). If the heat-resistant polyurethane film contains polyisocyanate (D) in such a range, for example, when a film having a thickness in the range of 20 to 60 μm is formed, at least 3 in 150% elongation at 180 ° C. in the heat resistance test. Before and after the implementation of a 200-hour accelerated test with a sunshine weather meter (watering once at 120 minutes at an atmospheric temperature of 63 ° C. for 18 minutes) in a weather resistance test. The film has excellent weather resistance such that the yellowing degree of the film is 20 or less in the difference of ΔN of the colorimeter (that is, the difference of ΔN = ΔN value after 200 hours−ΔN value of 0 hour), For example, when a multilayer with a hot melt layer is used, the film maintains excellent heat resistance without melting or thermal deterioration even under temperature conditions at which the hot melt layer can be melted. A film material having weather resistance, water resistance, and chemical resistance, high quality and high added value can be obtained.

Since the heat-resistant polyurethane film of the present invention has excellent heat resistance and weather resistance as described above, for example, when the heat-resistant polyurethane film is multilayered with the hot-melt layer in the processing step, the hot-melt layer It can be sufficiently tolerated without melting or thermal deterioration even under temperature conditions where it can be melted, and it can be used without any problem in practice without any significant deterioration in performance even under severe climatic environments.
In addition, the heat resistance test as used in the field of this invention evaluates the film created using the polyurethane resin composition on the conditions mentioned later using a hotplate.
The weather resistance test referred to in the present invention is an evaluation of a film prepared using a polyurethane resin composition under the conditions described later using a sunshine weather meter.

The polyurethane resin composition used in the heat-resistant polyurethane film of the present invention includes at least one selected from the group consisting of various pigments such as titanium oxide and carbon black, or various dyes such as azo dyes and anthraquinone dyes, It can mix | blend preferably in the range of 1-40 parts with respect to 100 parts of polyurethane resins (A), and it can color to the color according to a use by selecting and mix | blending these suitably.
In the heat-resistant polyurethane film of the present invention, if titanium oxide is used as a pigment and the blending amount is set in the above range, excellent concealability can be imparted.

Furthermore, the polyurethane resin composition used in the heat-resistant polyurethane film of the present invention may contain a leveling agent, such as an acrylic polymer, an amine salt of an acrylic polymer, a silicon compound, a higher alcohol, a vinyl type. Examples include at least one selected from the group consisting of a polymer and a silicone, and among these, an acrylic polymer is preferable.
The blending amount of the leveling agent in the polyurethane resin composition is preferably in the range of 0.01 to 5 parts, more preferably in the range of 0.05 to 2 parts, relative to 100 parts of the polyurethane resin (A). is there.
In general, when a pigment or the like is added to a solution of a polyurethane resin composition and coated on a release paper, bubbles may be difficult to escape from the coated resin solution. If a leveling agent is used in the range of this compounding quantity, the film which is excellent in surface property can be obtained.

In the polyurethane resin composition used for the heat-resistant polyurethane film of the present invention, various additives such as stabilizers and fillers can be used alone or in combination of two or more, as long as the object of the present invention is not impaired.
As the stabilizer, known and commonly used stabilizers can be used, and examples thereof include antioxidants such as hindered phenol compounds and hydrolysis inhibitors such as carbodiimide compounds, and are not particularly limited.
As the filler, known and commonly used fillers can be used, and examples thereof include calcium carbonate, talc, clay, bentonite and the like, and are not particularly limited.

  As a method for producing the heat-resistant polyurethane film of the present invention, a publicly known and commonly used production method can be adopted and is not particularly limited, and examples thereof include an extrusion molding method and a laminating method. Among these, as a precise manufacturing method, a laminating method is preferable. For example, a wet process silica (B), an ultraviolet absorber (C), and a crosslinking agent are added to a polyurethane resin (A) solution obtained by a solution reaction. As a method, after blending polyisocyanate (D) and other additives, it is cast on a release paper, dried after the solvent is dried, and then wound up.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to these Examples.
In the text, “parts” and “%” are based on mass unless otherwise specified.
Various characteristics were evaluated by the methods described below.

[Method for making heat-resistant polyurethane film]
A polyurethane resin composition for film containing a polyurethane resin (A), a wet process silica (B), an ultraviolet absorber (C), a polyisocyanate (D), and other additives as required is a release paper. , Dried at 70 ° C. for 2 minutes, then dried at 140 ° C. for 4 minutes, and further aged for 2 days at 35 ° C. under a relative humidity of 50%. A film was created.

[Evaluation method of heat resistance test]
A 150% stretched heat resistant polyurethane film (width 1 cm) was pressed against the end of a hot plate set at 180 ° C. for 3 seconds to determine whether or not the heat resistant polyurethane film was cut.
Criteria for heat resistance.
A: Restores the original state without cutting.
○: The original state is restored without cutting, but a white shape remains in the restored and restored part.
Δ: Not cut, but not restored from the stretched state ×: Cut.

[Evaluation method of weather resistance test]
Using a sunshine super long life weather meter (manufactured by Suga Test Instruments Co., Ltd.), in accordance with JIS Z-9105, an irradiance allowable range of 255 ± 45 W / m ² for 200 hours accelerated test (test conditions; ambient temperature 63 ° C. The water-resistant polyurethane film was evaluated for yellowing by the difference of ΔN of a color difference meter (spectral color meter CM3500-D manufactured by Minolta).
In addition, before the acceleration test, the ΔN value of the heat resistant polyurethane film was measured in advance, and the value was taken as the ΔN value for 0 hour.
ΔN difference = ΔN value after 200 hours−ΔN value at 0 hour

[Method for evaluating water resistance and solvent resistance (toluene resistance)]
A hot melt polyurethane resin (E) solution prepared in Synthesis Example 5 described later is cast on a release paper so that the resin thickness after drying is 50 μm, dried at 70 ° C. for 3 minutes, and then at 130 ° C. Drying for 3 minutes gave a polyurethane hot melt film. Between two heat-resistant polyurethane film 10cm × 10cm, 9cm × 7cm of narrowing scissors hot melt film, a hot press set at 0.99 ° C., the multilayer film and pressed for 5 seconds surface pressure of 1 kg / cm ² Got. Using the obtained multilayer film, it was immersed in water and toluene at 25 ° C. for 12 hours, the surface appearance (floating, peeling, etc.) was visually observed, and four-stage evaluation was performed according to the following criteria.
Evaluation criteria for water resistance and solvent resistance (toluene resistance).
A: No floating or peeling.
○: Floating and slightly peeled.
Δ: Floating in about half and peeling.
X: Dropped after treatment.

[Evaluation method for anti-blocking test]
A heat-resistant polyurethane film is cut into a size of 5 cm × 5 cm to form a test piece, which is superposed, subjected to a load of 200 g / cm ² under a 70 ° C. atmosphere, peeled off after 24 hours, and evaluated by whether or not it is peeled off. .
Evaluation criteria for blocking resistance.
○: Peel ×: Do not peel

[Measurement method of number average molecular weight]
Measurement model: GPC HLC8220 manufactured by Tosoh Corporation
Column: Tosohel HXL series used Measurement conditions: Measurement solvent THF solution, Measurement temperature 40 ° C

[Synthesis Example 1] << Preparation of solution of polyurethane resin (A-1) >>
100 parts of polybutylene adipate diol having a number average molecular weight (Mn) of 2000 are diluted with a mixed solvent of dimethylformamide (DMF) / methyl ethyl ketone (MEK) = 50/50 mass ratio to obtain 1,4-butanediol (BG). 8.4 parts and 35.0 parts of diphenylmethane diisocyanate (MDI) were allowed to react at 80 ° C. for 3 hours, and then the required amount of MDI was further added, the resin concentration was 50%, and the viscosity at 25 ° C. A solution of 30,000 mPa · s polyurethane resin (A-1) (diisocyanate structural unit content = 24 mass%) was obtained.

[Synthesis Example 2] << Preparation of solution of polyurethane resin (A-2) >>
A mixed solvent of 100 parts of polybutylene adipate diol having a number average molecular weight (Mn) of 2000 and 12 parts of bisphenol A-ethylene oxide 2-mole adduct in a dimethylformamide (DMF) / methyl ethyl ketone (MEK) = 50/50 weight ratio. After adding 6 parts of 1,4-butanediol (BG) and 38.0 parts of diphenylmethane diisocyanate (MDI), the mixture was reacted at 80 ° C. for 3 hours. A solution of a polyurethane resin (A-2) having a concentration of 50% and a viscosity at 25 ° C. of 31,000 mPa · s (content of diisocyanate structural unit = 24% by mass) was obtained.

[Synthesis Example 3] << Preparation of polyurethane resin (A-3) solution >>
The compound was synthesized in the same manner as in Synthesis Example 2 except that 33.0 parts of isophorone diisocyanate (IPDI) was used instead of diphenylmethane diisocyanate (MDI), the resin concentration was 50%, and the viscosity at 25 ° C. was 33,000 mPa · A solution of polyurethane resin (A-3) (isocyanate content = 22%) was obtained.

[Synthesis Example 4] << Preparation of solution of polyurethane resin (A-4) >>
Synthesis was conducted in the same manner as in Synthesis Example 2 except that 25.0 parts of hexamethylene diisocyanate (HDI) was used instead of diphenylmethane diisocyanate (MDI), the resin concentration was 50%, and the viscosity at 25 ° C. was 32,000 mPas. A solution of polyurethane resin (A-4) of s (content of diisocyanate structural unit = 17% by mass) was obtained.

[Synthesis Example 5] << Preparation of solution of polyurethane resin (A-5) >>
100 parts of polybutylene adipate diol having a number average molecular weight (Mn) of 2000 are diluted with a mixed solvent of dimethylformamide (DMF) / methyl ethyl ketone (MEK) = 50/50 mass ratio, and diphenylmethane diisocyanate (MDI) is 5.0. In addition, after reacting at 80 ° C. for 3 hours, a necessary amount of MDI was further added, and a polyurethane resin (A-5) (diisocyanate) having a resin concentration of 50% and a viscosity at 25 ° C. of 20,000 mPa · s. A solution having a constitutional unit content of 9% by mass was obtained.

[Synthesis Example 6] << Preparation of solution of polyurethane resin (E) for hot melt film >>
100 parts of polybutylene adipate diol having a number average molecular weight (Mn) of 600 is diluted with a mixed solvent of dimethylformamide (DMF) / methyl ethyl ketone (MEK) = 30/70 weight ratio to obtain 1,4-butanediol (BG). 0.74 parts and 42.5 parts of diphenylmethane diisocyanate (MDI) were reacted at 80 ° C. for 3 hours, and the necessary amount of MDI was further added. The resin concentration was 50%, and the viscosity at 25 ° C. was 25. A solution of polyurethane resin (E) for hot melt film of 1,000 mPa · s was obtained.

[Example 1]
(1) Preparation of heat-resistant polyurethane film 100 parts (solid content) of polyurethane resin (A-1) prepared in Synthesis Example 1 and wet method silica (trademark; manufactured by Tosoh Silica Co., Ltd .; nip gel, particle size 2.2) ˜2.8 μm), 14 parts of hindered amine, and 14 parts of xylylene diisocyanate trimethylolpropane adduct (XDI-TMP). The polyurethane resin composition solution thus obtained was cast on a release paper so that the resin thickness after drying was 50 μm, dried at 70 ° C. for 2 minutes, then dried at 140 ° C. for 4 minutes, and further 35 The heat-resistant polyurethane film of the present invention was obtained by aging at 50 ° C. and 50% relative humidity for 2 days.
(2) Preparation of hot melt film The solution of the polyurethane resin for hot melt (E) prepared in Synthesis Example 5 was cast on a release paper so that the resin thickness after drying was 50 μm, and then at 70 ° C. for 3 minutes. Drying was followed by drying at 130 ° C. for 3 minutes to obtain a polyurethane hot melt film.
(3) Preparation of multilayer film The 9 cm × 7 cm hot melt film prepared in (2) above is sandwiched between two 10 cm × 10 cm heat resistant polyurethane films prepared in (1) above, and the temperature is increased to 150 ° C. The multilayer film was obtained by press-bonding at a surface pressure of 1 kg / cm ² for 5 seconds with the set hot press.
The evaluation results of various films obtained as described above are shown in Table 1.

[Example 2] to [Example 5]
The raw material composition shown in Table 1 was blended by the same operation as in Example 1 to prepare a polyurethane resin composition, and the heat resistant polyurethane film of the present invention was prepared using the polyurethane resin composition. The evaluation results of various heat-resistant polyurethane films obtained as described above are shown in Tables 1 and 2.

[Comparative Example 1] to [Comparative Example 6]
The raw material compositions shown in Table 1 and Table 2 were blended by the same operation as in Example 1 to obtain a polyurethane resin composition, and a polyurethane film was further prepared. Although the evaluation result was shown in Table 2 and Table 3 as Comparative Examples 1-5, it was remarkably inferior in the balance of various characteristics, such as heat resistance and a weather resistance.

Note 1)
XDI-TMP; Trimethylolpropane adduct of xylylene diisocyanate IPDI-TMP; Trimethylolpropane adduct of isophorone diisocyanate

Note 2)
Composition of multilayer film: heat resistant polyurethane film / hot melt film / heat resistant polyurethane film

Note 3)
HDI-TMP; trimethylolpropane adduct of hexamethylene diisosonate

Note 4)
MDI-TMP; trimethylolpropane adduct of diphenylmethane diisocyanate

The heat-resistant polyurethane film of the present invention is excellent in heat resistance, weather resistance, water resistance, and solvent resistance, and is extremely useful for a wide range of applications such as coating films, multilayer films, and clothing.

Claims (6)

A polyol (a) having two or more groups having reactivity with an isocyanate group in the molecule and a molecular weight in the range of 60 to 140, and a number average molecular weight in the range of 140 to 4000 having two or more hydroxyl groups in the molecule. Polyol (b), at least one polyurethane resin (A) obtained from alicyclic diisocyanate and / or aromatic diisocyanate (c), wet-process silica (B), ultraviolet absorber (C), molecule The polyisocyanate (D) having 3 or more isocyanate groups therein is an essential component, and the content of diisocyanate structural units in the solid content of the polyurethane resin (A) is in the range of 10 to 40% by mass, Polyisocyanate (D) is isophorone diisocyanate, cyclohexane diisocyanate, dicyclohexylmethane diisocyanate Trimethylolpropane adducts, burettes, or the like obtained from alicyclic diisocyanates such as thiol and diisocyanates in which an isocyanate group is bonded via an methylene group to an aromatic ring such as xylylene diisocyanate and tetramethylxylylene diisocyanate A polyurethane resin which is at least one selected from the group consisting of isocyanurates, and the content of the polyisocyanate (D) is in the range of 5 to 30 parts with respect to 100 parts of the solid content of the polyurethane resin (A). A heat-resistant polyurethane film comprising the composition. In the molecule of the polyol (a) and / or the polyol (b) of the polyurethane resin (A), a bisphenol A-alkylene oxide adduct is bonded, and the polyurethane resin of the bisphenol A-alkylene oxide adduct ( The heat-resistant polyurethane film according to claim 1, wherein the content of A) in a solid content of 100 parts is in the range of 1 to 20 parts. The heat-resistant polyurethane film according to claim 1 or 2, wherein the content of the wet process silica (B) is in the range of 5 to 30 parts with respect to 100 parts of the solid content of the polyurethane resin (A). The heat resistance according to any one of claims 1 to 3, wherein the content of the ultraviolet absorber (C) is in the range of 0.1 to 7 parts with respect to 100 parts of the solid content of the polyurethane resin (A). Polyurethane film. The heat-resistant polyurethane film according to any one of claims 1 to 4, wherein the polyisocyanate (D) is a trimethylolpropane adduct of xylylene diisocyanate. The polyurethane resin (A), the wet-process silica (B), the ultraviolet absorber (C), and a polyurethane resin composition containing the polyisocyanate (D) as essential constituent components have a thickness of 20 to 60 μm. In the heat resistance test, the film can withstand 150% elongation at 180 ° C. for at least 3 seconds, and in the weather resistance test, a 200 hour acceleration test (atmosphere) The heat-resistant polyurethane film according to any one of claims 1 to 5, wherein the yellowing degree is 20 or less in terms of ΔN difference of the color difference meter before and after the execution of water spraying at a temperature of 63 ° C once every 120 minutes for 18 minutes.