JP2015160867A - Film having self-repairing property and production method of the same, and adhesive sheet using the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film having excellent transparency, heat resistance, weather resistance, strength, and flexibility and having excellent self-repairing property that the film repairs an incision flaw such as a cut and a large flaw by receiving heat.SOLUTION: The film comprises an acrylic polymer (A) containing at least a nitrogen-containing monomer (a1) as a monomer unit, and a crosslinked urethane polymer (B), in which the acrylic polymer (A) and the crosslinked urethane polymer (B) constitute a sea-island structure composed of a sea part and an island part. The island part is formed of the crosslinked urethane polymer (B), while the sea part is formed of the acrylic polymer (A).

Description

  The present invention relates to a film having self-healing properties, a method for producing the same, and an adhesive sheet using the film. More specifically, the film has the advantages and characteristics inherent in acrylic polymers and urethane polymers, is excellent in transparency, heat resistance, weather resistance, strength and flexibility, and has a self-repairing property that self-repairs by heating, and The manufacturing method and the adhesive sheet using the film are related.

  Self-healing materials that can be self-repaired even if some kind of scratch is made have been attracting much attention in recent years as intelligent materials. In recent years, active research has been conducted to naturally recover scratches and dents caused by pressure by using urethane-based materials with adjusted cross-link density and giving shape memory properties such as elastic stress and stress recovery. Yes.

For example, Patent Document 1 discloses a soft material composed of a base material layer containing a polycarbonate resin as a main component, a polymethyl methacrylate resin layer formed on the front and back surfaces of the base material layer, and a polyurethane resin having self-healing properties. A self-healing film having a resin layer is disclosed.
Patent Document 2 discloses a technique of using urethane (meth) acrylate obtained by reacting polyol, polyisocyanate, and hydroxyl group-containing (meth) acrylate as a self-healing material.
In Patent Document 3, a self-healing layer including a urethane (meth) acrylate or polyester (meth) acrylate curable resin and a thermoplastic resin dispersed therein is provided on a base material layer. A laminate is disclosed.

JP2013-144391A JP 2013-49839 A JP 2013-154631 A

The self-restoring film described in Patent Document 1 has a laminated structure of three or more layers, and the thickness of the urethane layer is limited. Therefore, the self-repairing property is limited, and small scratches disappear, but there is a problem that it is difficult to eliminate deep scratches and large scratches. Moreover, even with the technique described in Patent Document 2, there remains a problem that a cut wound or a large wound such as a cut is not restored.
The laminate described in Patent Document 3 is also effective for deep scratches that cannot be repaired by the stress recovery function of a conventional urethane material, but has a curable (meth) acrylic group at the end. Since the resin and the thermoplastic resin need to be dissolved and applied in a solvent, the compatibility between the two becomes important and the combination is limited. Moreover, it is necessary to dissolve the resin uniformly in a solvent, and there are problems such as requiring a large amount of an organic solvent and limiting the thickness. In addition, the process is complicated, and there is a problem that it takes time and cost.

  Therefore, the object of the present invention is to combine the advantages and characteristics inherent in acrylic polymers and urethane polymers, and is excellent in transparency, heat resistance, weather resistance, strength and flexibility, and cut scratches such as cuts and large scratches. It is to provide a film having self-healing property that self-repairs by heating, a method for producing the film, and an adhesive sheet using the film.

  As a result of intensive studies, the present inventor forms a sea-island structure by phase-separating an acrylic polymer (A) containing a specific monomer as a monomer unit and a crosslinked urethane polymer (B). The inventors have found that the above problems can be solved, and have completed the present invention.

That is, the present invention is achieved by the following [1] to [9].
[1] An acrylic polymer (A) containing at least a nitrogen-containing monomer (a1) as a monomer unit, and a crosslinked urethane polymer (B),
The acrylic polymer (A) and the crosslinked urethane polymer (B) form a sea-island structure composed of a sea part and an island part, and the island part is the crosslinked urethane polymer (B), The sea portion is the acrylic polymer (A).
[2] The content of the nitrogen-containing monomer (a1) is in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the total monomer units of the acrylic polymer (A). 1].
[3] The ratio of the acrylic polymer (A) and the crosslinked urethane polymer (B) is a mass ratio of the acrylic polymer (A) / crosslinked urethane polymer (B). [1] or [1], wherein the ratio of the component having a weight average molecular weight of 1 million or more in the acrylic polymer (A) is in the range of 3 to 10% by mass. The film according to [2].
[4] The film according to any one of [1] to [3], wherein the film self-repairs by heating.
[5] A method for producing the film according to any one of [1] to [4],
A first step of preparing a first mixture containing at least a partial polymer obtained by polymerizing a monomer component containing at least a nitrogen-containing monomer (a1), a polyol (b1) and a polyisocyanate (b2);
In the first mixture, the partial polymer is further polymerized to form an acrylic polymer (A), which contains at least an acrylic polymer (A), a polyol (b1), and a polyisocyanate (b2). A second step of preparing a mixture of the two,
A third step of obtaining a film by reacting at least the polyol (b1) and the polyisocyanate (b2) in the second mixture to form a crosslinked urethane polymer (B);
A method for producing a film, comprising:
[6] The film production as described in [5] above, wherein in the first step, a ratio of a component having a weight average molecular weight of 1 million or more in the partial polymer is in a range of 3 to 10% by mass. Method.
[7] The method for producing a film as described in [5] or [6], wherein in the first step and the second step, polymerization is performed by energy beam irradiation.
[8] In the second step, after the first mixture is coated on a support, the partial polymer is further polymerized by irradiation with energy rays to form the acrylic polymer (A), and then The method for producing a film according to any one of [5] to [7], wherein a film formed on the support is obtained by performing the third step.
[9] A pressure-sensitive adhesive sheet comprising the film according to any one of [1] to [4] and a pressure-sensitive adhesive layer provided on at least one surface of the film.

  The film of the present invention separates each function by phase-separating an acrylic polymer containing at least a nitrogen-containing monomer as a monomer unit and a crosslinked urethane polymer to form a sea-island structure. In other words, the acrylic polymer in the sea part has self-healing properties due to thermoplasticity, and the cross-linked urethane polymer in the island part has self-healing properties due to the stress recovery effect, so that cuts such as cuts and large scratches can be prevented. However, excellent self-repairing properties can be expressed. In addition, the film of the present invention can satisfy both of the advantages and characteristics inherent in both the transparency, heat resistance and weather resistance of the acrylic polymer, and the excellent stress recovery of the urethane polymer. Therefore, according to the present invention, a film having excellent self-healing properties, which is excellent in transparency, heat resistance, weather resistance, strength and flexibility, and capable of self-healing cuts and large scratches such as cuts by heating, and production thereof A method can be provided. Moreover, the adhesive sheet which provided the adhesive layer in the at least one surface of the said film can be provided.

(A) is a figure which shows the TEM image of magnification 10000 times of the film A obtained in Example 1, (b) is a figure which shows the TEM image of magnification 25000 times of the film A. (A) is a figure which shows the TEM image of magnification 10000 times of the film C obtained in Example 3, (b) is a figure which shows the TEM image of magnification 25000 times of the film C.

Hereinafter, the present invention will be described in more detail.
In the present invention, the term “film” includes a sheet, and the term “sheet” includes a film.

The film of the present invention comprises an acrylic polymer (A) containing at least a nitrogen-containing monomer (a1) as a monomer unit, and a crosslinked urethane polymer (B), the acrylic polymer (A) and The crosslinked urethane polymer (B) forms a sea-island structure composed of a sea part and an island part, the island part is the crosslinked urethane polymer (B), and the sea part is the acrylic polymer. It is (A).
In the film of the present invention, as described above, the acrylic polymer (A) and the crosslinked urethane polymer (B) form a sea-island structure composed of a sea part and an island part by phase separation. In the sea-island structure, island portions that are independent phases are dispersed in sea portions that are continuous phases. The acrylic polymer (A) constitutes a sea portion as a continuous phase, and the crosslinked urethane polymer (B) constitutes an island portion as an independent phase.

<Acrylic polymer (A)>
The acrylic polymer (A) in the present invention contains at least a nitrogen-containing monomer (a1) as a monomer unit. The said acrylic polymer (A) comprises the sea part of the sea island structure which the film of this invention has.

Examples of the nitrogen-containing monomer (a1) include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N-butyl (meth). (Meth) acrylamide monomers such as acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, (meth) acryloylmorpholine; for example, aminoethyl (meth) acrylate, N (meth) acrylic acid, N-dimethylaminoethyl, amino group-containing monomer having primary, secondary or tertiary at the terminal, such as t-butylaminoethyl (meth) acrylate; for example, cyano group-containing monomer such as acrylonitrile, methacrylonitrile; N -Vinylpyrrolidone, N- (1-Me Pyrrolidone monomers such as ruvinyl) pyrrolidone; for example, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, Vinyl group-containing heterocyclic compounds such as N-vinylmorpholine; Vinylcarboxylic acid amide compounds such as N-vinylacetamide; Maleimides such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide Monomer; for example, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexitaconimide, N-cyclohexylitaconimide, N Itaconic imide monomers such as lauryl itaconimide; for example, N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyoctamethylene succinimide, etc. Other examples include succinimide monomers; sulfonic acid group-containing (meth) acrylamide monomers such as 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, and diacetone acrylamide. These monomers can be used alone or in combination of two or more.
In the present specification, “(meth) acryl” means acryl and / or methacryl, and “(meth) acryloyl” means acryloyl and / or methacryloyl.

  Among these, from the viewpoint of easily forming a sea-island structure and imparting better self-healing properties, the nitrogen-containing monomer (a1) is preferably a pyrrolidone monomer, a (meth) acrylamide monomer, or a vinyl group-containing heterocyclic compound. Pyrrolidone monomers having a heterocyclic skeleton and vinyl group-containing heterocyclic compounds are more preferred.

  The content of the nitrogen-containing monomer (a1) is preferably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the total monomer units of the acrylic polymer (A). When the content of the nitrogen-containing monomer (a1) is within the above range, an effect of easily forming a sea-island structure and imparting better self-repairability can be achieved. The content of the nitrogen-containing monomer (a1) is more preferably 1 to 25 parts by mass, and further preferably 5 to 20 parts by mass.

  In the present invention, a monomer component other than the nitrogen-containing monomer (a1) is further used as a monomer component for forming the acrylic polymer (A) as long as the formation of the sea-island structure of the film of the present invention is not hindered. May be. Examples of such monomer components include acrylic monomers (a2) and vinyl monomers.

  The acrylic monomer (a2) is contained for controlling the glass transition temperature (Tg) of the acrylic polymer (A). Acrylic monomers (a2) can be combined with various types of monomers, making it easier to control the glass transition temperature (Tg) and enabling self-healing by heating below temperatures that do not cause thermal decomposition of the polymer. Become. If the glass transition temperature (Tg) of the acrylic polymer (A) is too high, the polymer will be thermally decomposed and the resulting film will not have self-healing properties. Specifically, the preferable glass transition temperature (Tg) is in the range of 20 to 200 ° C, more preferably in the range of 30 to 150 ° C.

The acrylic monomer (a2) is preferably an acrylic monomer having a radical polymerizable group that is cured by energy rays. For example, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n- Butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, Carboxyl group-containing monomers such as dodecyl (meth) acrylate and n-octadecyl (meth) acrylate; monomers having an alicyclic structure such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate . Moreover, cyanoacrylate monomers such as acrylonitrile and methacrylonitrile, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, fluorine (meth) acrylate, silicone Examples include acrylic acid ester monomers such as (meth) acrylate and 2-methoxyethyl (meth) acrylate; monomers such as methyl (meth) acrylate and octadecyl (meth) acrylate. These monomers can be used alone or in combination of two or more. These acrylic monomers are appropriately determined in kind, combination, amount of use, and the like in consideration of the polymerizability upon curing by energy beam irradiation and the characteristics of the high molecular weight obtained.
In the present specification, “(meth) acrylate” means acrylate and / or methacrylate.

  The content of the acrylic monomer (a2) is preferably in the range of 70 to 99 parts by mass with respect to 100 parts by mass of the total monomer units of the acrylic polymer (A). When the content of the acrylic monomer (a2) is within this range, the excellent transparency, heat resistance and weather resistance inherent in the acrylic polymer can be more effectively maintained. Moreover, it is easy to form a sea-island structure, and the effect of imparting better self-repairing properties can also be achieved. The content of the acrylic monomer (a2) is more preferably 75 to 99 parts by mass, and further preferably 80 to 95 parts by mass.

  In the present invention, the monomer component for forming the acrylic polymer (A) may further include a monomer component other than the above-described monomer as long as the formation of the sea-island structure of the film of the present invention is not hindered. Good. Examples of such monomer components include vinyl monomers such as vinyl acetate, N-vinyl pyrrolidone, N-vinyl carboxylic acid amides, N-vinyl caprolactam, and the like.

<Crosslinked urethane polymer (B)>
The crosslinked urethane polymer (B) in the present invention (hereinafter also referred to as “crosslinked urethane polymer (B)”) constitutes an island portion of the sea-island structure possessed by the film of the present invention. The crosslinked urethane polymer (B) in the present invention is formed by reacting at least the polyol (b1) and the polyisocyanate (b2). That is, the crosslinked urethane polymer (B) may be formed by reacting only the polyol (b1) and the polyisocyanate (b2), or by reacting the crosslinking agent together with the polyol (b1) and the polyisocyanate (b2). A crosslinked urethane polymer (B) may be formed.
For the crosslinking, known crosslinking methods such as a crosslinking method by heating can be employed.

  As the polyol (b1), those having two or more hydroxyl groups in one molecule are desirable. Examples of the low molecular weight polyol include divalent alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and hexamethylene glycol, and trivalent or tetravalent alcohols such as trimethylolpropane, glycerin, and pentaerythritol. Examples of the polymer polyol include polyether polyol, polyester polyol, polycarbonate polyol, polyolefin polyol, and polyacryl polyol. The number average molecular weight of the polymer polyol is usually 500 or more, preferably 500 to 10,000, more preferably 550 to 4000. Polyol (b1) can be used alone or in combination of two or more.

  Examples of the polyether polyol include polyalkylene ether glycols such as polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol (PTMG), and a plurality of alkylene oxides as monomer components such as an ethylene oxide-propylene oxide copolymer. (Alkylene oxide-other alkylene oxide) copolymer containing etc. are mentioned.

  Examples of the polyester polyol include a condensation polymer of a polyhydric alcohol and a polyvalent carboxylic acid; a ring-opening polymer of a cyclic ester (lactone); a reaction by three kinds of components: a polyhydric alcohol, a polyvalent carboxylic acid, and a cyclic ester. Things can be used. In the condensation polymerization product of polyhydric alcohol and polycarboxylic acid, examples of polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1 , 3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, glycerin, trimethylolpropane, trimethylolethane, cyclohexanediol (Such as 1,4-cyclohexanediol), cyclohexanedimethanols (such as 1,4-cyclohexanedimethanol), bisphenols (such as bisphenol A), sugar alcohols (such as xylitol and sorbitol), etc. Kill. On the other hand, examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids such as malonic acid, maleic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; 1,4-cyclohexanedicarboxylic acid, etc. And aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid and trimellitic acid. In the ring-opening polymer of cyclic ester, examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone. In the reaction product of the three types of components, those exemplified above can be used as the polyhydric alcohol, polycarboxylic acid, and cyclic ester.

  Examples of the polycarbonate polyol include a reaction product of a polyhydric alcohol and phosgene, chloroformate, dialkyl carbonate or diaryl carbonate; a ring-opening polymer of a cyclic carbonate (such as alkylene carbonate). Specifically, in the reaction product of polyhydric alcohol and phosgene, the polyhydric alcohol includes the polyhydric alcohols exemplified above (for example, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol). , Neopentyl glycol, 1,6-hexanediol, etc.) can be used. In the ring-opening polymer of cyclic carbonate, examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, hexamethylene carbonate, and the like. In addition, the polycarbonate polyol should just be a compound which has a carbonate bond in a molecule | numerator, and the terminal is a hydroxyl group, and may have an ester bond with a carbonate bond. Representative examples of polycarbonate polyols include polyhexamethylene carbonate diol, diol obtained by ring-opening addition polymerization of lactone to polyhexamethylene carbonate diol, and co-condensate of polyhexamethylene carbonate diol with polyester diol or polyether diol. Etc.

  The polyolefin polyol is a polyol having an olefin as a component of the skeleton (or main chain) of the polymer or copolymer and having at least two hydroxyl groups in the molecule (particularly at the terminal). The olefin may be an olefin having a carbon-carbon double bond at the terminal (for example, an α-olefin such as ethylene or propylene), or an olefin having a carbon-carbon double bond at a position other than the terminal. (For example, isobutene and the like) and diene (for example, butadiene, isoprene and the like) may be used. Typical examples of polyolefin polyols include butadiene homopolymers, isoprene homopolymers, butadiene-styrene copolymers, butadiene-isoprene copolymers, butadiene-isoprene copolymers such as butadiene-modified polymers modified with hydroxyl groups at the ends. .

The polyacrylic polyol is a polyol having (meth) acrylate as a component of the polymer (or copolymer) skeleton (or main chain) and having at least two hydroxyl groups in the molecule (particularly at the terminal). As the (meth) acrylate, (meth) acrylic acid alkyl ester [for example, (meth) acrylic acid C _1-20 alkyl ester, etc.] is preferably used.

  These polyols (b1) can be used alone or in combination of two or more. Moreover, in this invention, it is preferable to use diol as a polyol (b1) from a viewpoint of the intensity | strength of the film which has a self-restoring property. Preferred examples of these polyols (b1) include polyether polyols, polycarbonate polyols, and polyester polyols. Among them, particularly preferred examples include polytetramethylene ether glycol (PTMG).

Examples of the polyisocyanate (b2) include aromatic, aliphatic and alicyclic diisocyanates, dimers and trimers of these diisocyanates. Aromatic, aliphatic, and alicyclic diisocyanates include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate. 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4 -Diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methyl Cyclohexane diisocyanate, m- tetramethylxylylene diisocyanate. Moreover, these dimers, trimers, and polyphenylmethane polyisocyanate are used. Examples of the trimer include isocyanurate type, burette type, and allophanate type, and can be used as appropriate.
These polyisocyanates (b2) can be used alone or in combination of two or more. From the viewpoints of urethane reactivity, compatibility with acrylic, and the like, the type and combination of polyisocyanates may be appropriately selected. From the viewpoint of prompt reaction with the polyol and suppression of the reaction with water, it is preferable to use an alicyclic diisocyanate.

  In the present invention, the ratio of the polyol (b1) and the polyisocyanate (b2) used to form the crosslinked urethane polymer (B) is not particularly limited. For example, NCO / OH (equivalent ratio) is 1 It is preferably 0.0 or more, more preferably 1.0 or more and 3.0 or less. If NCO / OH is less than 1.0, the molecular chain length of the urethane polymer cannot be extended sufficiently, and the film strength and elongation tend to decrease. Moreover, if NCO / OH is 3.0 or less, sufficient flexibility can be ensured.

  In forming the crosslinked urethane polymer (B) in the film of the present invention, in addition to the above-described polyol (b1) and polyisocyanate (b2), if necessary, a crosslinking agent may be further reacted to form a crosslinked structure. Good.

As the crosslinking agent, a conventionally known crosslinking agent can be used, and among them, a polyfunctional isocyanate is preferable.
The said crosslinking agent may be used individually by 1 type, or may mix and use 2 or more types.
Specifically, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene diisocyanate trimer adduct (trade name “ Isocyanate adducts such as coronate HL "manufactured by Nippon Polyurethane Industry Co., Ltd., isocyanurate of hexamethylene diisocyanate (trade name" Coronate HX "manufactured by Nippon Polyurethane Industry Co., Ltd.); polyether polyisocyanate, polyester polyisocyanate, and various kinds thereof Examples include adducts with polyols; polyisocyanates polyfunctionalized with isocyanurate bonds, burette bonds, allophanate bonds, and the like.

The use ratio of the crosslinking agent is preferably 10 to 50 parts by mass, and more preferably 20 to 40 parts by mass with respect to 100 parts by mass of the polyol (b1).
The use ratio of the crosslinking agent is preferably 10 parts by mass or more, which is preferable in terms of the strength of the self-repairing film, and it is preferably 50 parts by mass or less in terms of ensuring transparency.

  The ratio of the acrylic polymer (A) and the crosslinked urethane polymer (B) in the film of the present invention is 60/40 as a mass ratio of the acrylic polymer (A) / crosslinked urethane polymer (B). It is preferable that it is in the range of ˜95 / 5 from the viewpoint of self-repairing, more preferably in the range of 65/35 to 95/5, and in the range of 70/30 to 90/10. Particularly preferred.

  In the film of the present invention, the shape of the island portion made of the crosslinked urethane polymer (B) can take any geometric shape such as a circular shape or an elliptical shape, and is not particularly limited. . The size of the island portion is preferably 500 nm or less from the viewpoint of increasing the transparency of the film. Here, the size of the island portion can be appropriately adjusted depending on the molecular weight of the acrylic syrup, the ratio of the prepolymer, and the like. A more preferable size of the island portion is 10 to 500 nm. In addition, the size of the island part in this invention means the average diameter of arbitrary island parts observed when the film of this invention is observed with an electron microscope. The average diameter is calculated by performing analysis processing on the obtained image.

  In addition, the film of the present invention may contain, as necessary, commonly used additives such as ultraviolet absorbers, anti-aging agents, fillers, pigments, colorants, flame retardants, antistatic agents, and light stabilizers. It can add within the range which does not inhibit the effect of this invention. These additives are used in normal amounts depending on the type.

  Although the thickness of the film of this invention should just be determined suitably according to a use, it is 10-500 micrometers, for example, Preferably it is 30-300 micrometers.

<The manufacturing method of the film of this invention>
Next, an aspect of the film production method of the present invention will be described.
The film of the present invention is, for example, a step of preparing a first mixture containing at least a partial polymer obtained by polymerizing a monomer component containing at least a nitrogen-containing monomer (a1), a polyol (b1) and a polyisocyanate (b2). (First step) and in the first mixture, the partial polymer is further polymerized to form an acrylic polymer (A), and at least the acrylic polymer (A), polyol (b1) and poly A step of preparing a second mixture containing isocyanate (b2) (second step), and a urethane polymer crosslinked by reacting at least polyol (b1) and polyisocyanate (b2) in the second mixture (B) is formed, and it can manufacture by the manufacturing method including the process (3rd process) which obtains a film.

(First step)
In the first step, first, a first mixture containing at least a partial polymer obtained by polymerizing a monomer component containing at least a nitrogen-containing monomer (a1), a polyol (b1), and a polyisocyanate (b2). Prepare.

First, the partial polymer in the first mixture will be described.
The partial polymer is obtained by polymerizing a monomer component containing at least a nitrogen-containing monomer (a1). In forming the partial polymer, from the viewpoint of formation of the sea-island structure, it is preferable to polymerize 1 to 15% by mass of all monomer components for forming the acrylic polymer (A), It is more preferable to polymerize 3 to 10% by mass.

  Examples of the polymerization method for forming the partial polymer include polymerization by energy beam irradiation, solution polymerization, and emulsion polymerization. From the viewpoint of increasing the molecular weight of the partial polymer, polymerization by energy beam irradiation is preferable. Energy rays used for polymerization by irradiation with energy rays include radiation such as ultraviolet rays (UV), ionizing radiation such as α rays, β rays, γ rays, neutron rays, electron rays, and visible rays. Also good. At that time, a photopolymerization initiator is used. At this time, in order to avoid polymerization inhibition due to oxygen, the oxygen concentration may be reduced by filling the reaction vessel with an inert gas such as nitrogen. In addition, you may perform a vacuum defoaming process before superposition | polymerization for bubble removal.

  Examples of the photopolymerization initiator include a benzoin ether photopolymerization initiator, an acetophenone photopolymerization initiator, an α-ketol photopolymerization initiator, an aromatic sulfonyl chloride photopolymerization initiator, and a photoactive oxime photopolymerization initiator. Agents, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, and the like can be used. . A photoinitiator can be used individually or in combination of 2 or more types.

  Specifically, examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether. Examples of the acetophenone-based photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone [for example, trade name “Irgacure 184” (manufactured by Ciba Specialty Chemicals, etc.), 2,2-diethoxyacetophenone, 2,2-dimethoxy. -2-phenylacetophenone, 4-phenoxydichloroacetophenone, 4- (t-butyl) dichloroacetophenone and the like. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one, and the like. . Examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalene sulfonyl chloride. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the benzyl photopolymerization initiator include benzyl. Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinyl benzophenone, α-hydroxycyclohexyl phenyl ketone, and the like. Examples of the ketal-based photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one [for example, trade name “Irgacure 651” (manufactured by Ciba Specialty Chemical Co., Ltd.]) and the like. . Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like. As the acylphosphine oxide photopolymerization initiator, for example, trade name “Lucirin TPO” (manufactured by BASF) or the like can be used.

  Although it does not restrict | limit especially as the usage-amount of a photoinitiator, For example, 0.01-5 mass parts (preferably 0.05-3 weight part) with respect to 100 mass parts of the monomer whole quantity which comprises an acryl-type monomer. You can choose from a range of

The irradiation energy, irradiation time, irradiation method and the like of the energy beam are not particularly limited as long as the partial polymer can be formed by activating the photopolymerization initiator and causing the reaction of the monomer component.
For example, the irradiation amount of ultraviolet rays or the like can be arbitrarily set according to the required degree of partial polymerization. Generally, the dose of ultraviolet rays, 100~5000mJ / cm ^2, preferably not 1000~4000mJ / cm ^2, more preferably a 2000~4000mJ / cm ^2. When the dose of ultraviolet ray is less than 100 mJ / cm ^2, may not sufficient polymerization rate can be obtained, when it is more than 5000 mJ / cm ^2, there is a possibility that the polymerization becomes too advanced.
Moreover, there is no restriction | limiting in particular also about the irradiation time of an ultraviolet-ray, Although it can set arbitrarily according to an irradiation amount, Usually, an ultraviolet-ray is irradiated within 1 to 10 minutes.
Also, the temperature at the time of ultraviolet irradiation is not particularly limited and can be set arbitrarily. However, if the temperature is too high, a termination reaction due to polymerization heat tends to occur, which tends to cause deterioration of characteristics. The temperature is usually 80 ° C. or lower, preferably 70 ° C. or lower, more preferably 60 ° C. or lower.
Moreover, the weight average molecular weight of the whole partial polymer obtained is 100000-5 million, for example, Preferably it is 100000-4 million.
Moreover, from the viewpoint of the strength of the film having self-healing properties, the proportion of the component having a weight average molecular weight of 1 million or more in the formed partial polymer is preferably in the range of 3 to 10% by mass. More preferably, it is in the range of mass%.

  In preparing the first mixture, for example, a monomer component containing at least a nitrogen-containing monomer (a1) is first polymerized to form a partial polymer, and then a polyol (b1) and a polyisocyanate (b2) are prepared. ) May be added. Alternatively, in the presence of a part or all of the polyol (b1) and / or the polyisocyanate (b2), a monomer component containing at least the nitrogen-containing monomer (a1) is polymerized to form a partial polymer, and then, as necessary. Accordingly, the remaining polyol (b1) and / or polyisocyanate (b2) may be added.

(Second step)
Subsequently, in the second step, the partial polymer is further polymerized in the first mixture to form an acrylic polymer (A), and at least the acrylic polymer (A), the polyol (b1) and the polyisocyanate. A second mixture containing (b2) is prepared.

Examples of the polymerization method for forming the acrylic polymer (A) include polymerization by energy beam irradiation, solution polymerization, emulsion polymerization, and the like. From the viewpoint of self-repairing, polymerization by energy beam irradiation is preferable. . Moreover, from the viewpoint of the strength of the film having self-healing ability, it is more preferable to perform polymerization by irradiation with energy rays in both the first step and the second step.
Energy rays used for polymerization by irradiation with energy rays include radiation such as ultraviolet rays (UV), ionizing radiation such as α rays, β rays, γ rays, neutron rays, electron rays, and visible rays. Also good. At that time, a photopolymerization initiator is used. At this time, in order to avoid polymerization inhibition due to oxygen, the oxygen concentration may be reduced by filling the reaction vessel with an inert gas such as nitrogen.
As a photoinitiator, the thing similar to the photoinitiator used when forming a partial polymer can be used. In addition, when performing polymerization by energy ray irradiation in both the first step and the second step, a photopolymerization initiator in an amount necessary for forming the acrylic polymer (A) is previously added in the first step. Alternatively, a part of the photopolymerization initiator in an amount necessary for forming the acrylic polymer (A) may be added in the first step, and the remaining photopolymerization initiator may be added in the second step. It may be added.
In order to suppress the generation of bubbles in the film, vacuum defoaming treatment may be performed before polymerization.

Here, the first mixture is applied onto a support that is optionally peeled off, and irradiated with energy rays according to the type of the photopolymerization initiator and the like, and the partial polymer is further polymerized to obtain an acrylic polymer ( It is preferable to carry out the second step by forming A). In the case of this embodiment, the film formed on the support body can be obtained by performing the 3rd process mentioned later after that.
At this time, in order to avoid polymerization inhibition by oxygen, a cover separator may be put on the first mixture coated on the support to block oxygen, or an inert gas such as nitrogen may be put in the reaction vessel. It may be filled to reduce the oxygen concentration.

  Here, the support may be subjected to a peeling treatment or may not be subjected to a peeling treatment, and is not particularly limited. For example, a separator can be used. The separator is not particularly limited, and a conventional release paper, a separator having a release treatment layer, a low adhesive substrate made of a fluoropolymer, a low adhesive substrate made of a nonpolar polymer, and the like can be used. Examples of the separator having the release treatment layer include a plastic film or paper surface-treated with a release treatment agent such as silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide. Examples of the fluorine-based polymer in the low adhesion substrate made of the above-mentioned fluoropolymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chloro Examples include fluoroethylene-vinylidene fluoride copolymer. Moreover, as said nonpolar polymer, olefin resin (for example, polyethylene, a polypropylene, etc.) etc. are mentioned, for example. The separator can be manufactured by a known or conventional method. Further, the thickness of the separator is not particularly limited.

  In addition, as a support body, it is preferable to use what does not inhibit permeation | transmission of an energy ray, when performing superposition | polymerization by energy ray irradiation. Further, the surface of the support is subjected to a conventional surface treatment, for example, corona treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage impact exposure, oxidation treatment by chemical or physical methods such as ionizing radiation treatment, and the like. Or a coating treatment with an undercoat agent or a release agent.

  The thickness of the support can be appropriately selected according to the strength, flexibility, purpose of use, and the like, and is generally 1 to 1000 μm, preferably 1 to 500 μm, more preferably about 3 to 300 μm. However, it is not limited to these. Note that the support may have any form of a single layer or a laminate.

  The release treatment agent is not particularly limited, and for example, a silicone release treatment agent, a fluorine release treatment agent, a long-chain alkyl release treatment agent, or the like can be used. You may use a mold release processing agent individually or in combination of 2 or more types. Note that the support subjected to the release treatment with the release treatment agent is formed by, for example, a known formation method.

  Further, the cover separator when the cover separator is placed on the first mixture coated on the support to block oxygen is not particularly limited. For example, the same separator as the support is used. be able to.

The viscosity of the first mixture (hereinafter also referred to as syrup) when applying the first mixture on the support is the temperature at which the coating is applied (for example, 10 to 40 ° C.) from the viewpoint of workability and the like. For example, 0.1 to 50 Pa · s, and the upper limit is preferably 30 Pa · s, more preferably 20 Pa · s, and the lower limit is preferably 0. .5 Pa · s, more preferably 1 Pa · s. If the viscosity is too low, the shape tends to be difficult to maintain. Conversely, if the viscosity is too high, the coating workability tends to decrease.
The coating method is not particularly limited, and for example, a coater such as a Meyer bar, a blade coater, an air knife coater, a roll coater or a die coater, an extruder or a printing machine can be used.
A small amount of solvent may be added for adjusting the viscosity of the coating. The solvent can be appropriately selected from commonly used solvents, and examples thereof include ethyl acetate, toluene, chloroform, dimethylformamide and the like. The solvent may be added at any stage as long as it is before coating.

In addition, the energy ray irradiation amount, irradiation time, irradiation method, and the like when performing polymerization by energy ray irradiation are not particularly limited, and the photopolymerization initiator is activated to cause a reaction of the monomer component, thereby causing an acrylic heavy polymer. What is necessary is just to be able to form the coalescence (A).
For example, the amount of irradiation such as ultraviolet rays can be arbitrarily set according to the required film characteristics. Generally, the dose of ultraviolet rays, 100~5,000mJ / cm ^2, preferably not 1,000~4,000mJ / cm ^2, more preferably a 2,000~3,000mJ / cm ^2. When the irradiation amount of ultraviolet rays is less than 100 mJ / cm ² , a sufficient polymerization rate may not be obtained, and when it is more than 5,000 mJ / cm ² , deterioration may be caused.
Moreover, there is no restriction | limiting in particular also about the irradiation time of an ultraviolet-ray, Although it can set arbitrarily according to an irradiation amount, Usually, an ultraviolet-ray is irradiated within 1 to 10 minutes.
Also, the temperature at the time of ultraviolet irradiation is not particularly limited and can be set arbitrarily. However, if the temperature is too high, a termination reaction due to polymerization heat tends to occur, which tends to cause deterioration of characteristics. The temperature is usually 80 ° C. or lower, preferably 70 ° C. or lower, more preferably 60 ° C. or lower.
The acrylic polymer (A) thus formed has a weight average molecular weight of, for example, 100,000 to 1,000,000, preferably 200,000 to 1,000,000.

(Third step)
Subsequently, in the third step, in the second mixture, at least polyol (b1) and polyisocyanate (b2) are reacted to form a crosslinked urethane polymer (B) to obtain a film.

Here, as a polymerization method for forming the crosslinked urethane polymer (B) by reacting at least the polyol (b1) and the polyisocyanate (b2), a known polymerization method, for example, a polymerization method by heating, may be employed. Can do. The polymerization conditions by heating are appropriately adjusted depending on the types and amounts of the polyol (b1) and polyisocyanate (b2) to be reacted, and are not particularly limited. For example, the heating temperature is 30 It is in the range of ˜200 ° C., and the heating time is 0.01 to 3 hours. Note that heat treatment may be performed a plurality of times at different heating temperatures.
Further, the atmosphere when forming the crosslinked urethane polymer (B) by reacting at least the polyol (b1) and the polyisocyanate (b2) is not particularly limited as long as the reaction is not inhibited.

Further, in performing the third step, a urethane polymer (B) which is crosslinked by reacting at least the polyol (b1) and the polyisocyanate (b2) after coating the second mixture on a support which is optionally peel-treated. ) To form a film. In the case of this embodiment, a film formed on a support can be obtained.
In addition, the viscosity of the second mixture when applying the second mixture on the support is the temperature at the time of coating (for example, a predetermined temperature within a range of 10 to 40 ° C., from the viewpoint of workability, etc. In particular, at 25 ° C., for example, 0.1 to 50 Pa · s, the upper limit is preferably 30 Pa · s, more preferably 20 Pa · s, and the lower limit is preferably 0.5 Pa · s, more preferably. Is 1 Pa · s. If the viscosity is too low, the shape tends to be difficult to maintain. Conversely, if the viscosity is too high, the coating workability tends to decrease.
The coating method is not particularly limited, and for example, a coater such as a Meyer bar, a blade coater, an air knife coater, a roll coater or a die coater, an extruder or a printing machine can be used.
A small amount of solvent may be added for adjusting the viscosity of the coating. The solvent can be appropriately selected from commonly used solvents, and examples thereof include ethyl acetate, toluene, chloroform, dimethylformamide and the like. The solvent may be added at any stage as long as it is before coating.

  For example, the film of the present invention can be produced by the above-described film production method. In the case where a film formed on a support is produced, the film of the present invention can be obtained by peeling the film from the support, or the film formed on the support can be used as it is. And the film of the present invention can be integrated.

In the film of the present invention, as described above, the acrylic polymer (A) and the crosslinked urethane polymer (B) form a sea-island structure composed of a sea part and an island part by phase separation. And by combining the self-healing property due to the thermoplasticity of the acrylic polymer in the sea part and the self-healing property due to the stress recovery effect of the cross-linked urethane polymer in the island part, cutting wounds such as cuts and large scratches are prevented. Can also be self-repaired by heating.
For example, the self-repairing property by heating can be expressed even for a cut wound or a large wound having a wound length of 10 mm or more and / or a wound depth of 30 μm or more. The function of self-repairing such cuts and large scratches is an excellent function of the film of the present invention that cannot be achieved by the prior art. In addition, as heating temperature at the time of performing self-repair by heating, depending on the length and depth of the wound, the type of material constituting the film, and the like, it is not particularly limited, for example, 30 to 200 ° C., The heating time is preferably 50 to 150 ° C., and the heating time is, for example, 10 minutes or less, preferably 1 to 10 minutes.

  In addition, the film of the present invention has self-healing property by heating, and is excellent in transparency, heat resistance, weather resistance, strength and flexibility.

  The film of the present invention can protect the surface of such articles by directly or using an adhesive on the surface of articles to be protected, for example, optical members such as touch panels, car bodies such as automobiles, and building materials. Useful as a film.

  In the present invention, depending on the article to be protected, for example, in the second step, after applying the first mixture on the surface of the article instead of the support, the same method as described above is used. It is also possible to form a coating directly on the surface of the article. Alternatively, in the third step, after the second mixture is applied on the surface of the article instead of the support, a coating film can be directly formed on the surface of the article by the same method as described above. The film of the present invention includes a coating film directly formed on the surface of the article to be protected in this way.

  Moreover, this invention also provides the adhesive sheet which provided the adhesive layer on the at least one surface of the film of this invention. By sticking the pressure-sensitive adhesive sheet to an article to be protected through a pressure-sensitive adhesive layer, the pressure-sensitive adhesive sheet can be used as a protective pressure-sensitive adhesive sheet. In addition, in order to express the self-repairing property by heating which the film of this invention has more effectively, it is preferable to provide an adhesive layer only on one side of the film of this invention.

  The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, and general materials such as acrylic, rubber-based, and silicon-based materials can be used. However, adhesiveness at low temperature, retention at high temperature, and cost. In consideration of the surface and the like, an acrylic adhesive is preferable.

  As an acrylic pressure-sensitive adhesive, an acrylic copolymer obtained by copolymerizing a monomer component mainly composed of an acrylate ester and a monomer component having a functional group such as a carboxyl group or a hydroxyl group (may be two or more types) An acrylic pressure-sensitive adhesive containing can be used.

  Examples of acrylic esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec- Butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) Acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) Acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, Nonadecyl (meth) acrylate, eicosyl (meth) acrylate, isobornyl (meth) acrylate, 1-adamantyl (meth) acrylate, and the like can be given. These alkyl (meth) acrylates can be used alone or in combination of two or more.

  The following monomer components can be copolymerized with the alkyl (meth) acrylate. Examples of copolymerizable monomer components include monomers containing carboxyl groups such as (meth) acrylic acid, itaconic acid, maleic acid, crotonic acid, fumaric acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, and the like. ; 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxy (meth) acrylate Hydroxyl group-containing monomers such as octyl, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) -methyl (meth) acrylate; glycidyl (meth) acrylate, methylglycidyl (Meta Glycidyl group-containing monomers such as acrylate; Cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethyl (meta ) Acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, (meth) acryloylmorpholine, N-vinyl-2-piperidone, N-vinyl-3- Morpholinone, N-vinyl-2-caprolactam, N-vinyl-2-pyrrolidone, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-cyclohexylmaleimide, N- Phenylmaleimide N- acryloyl pyrrolidine, t- butyl aminoethyl (meth) nitrogen-containing monomers such as acrylates, styrene derivatives and styrene, monomers such as vinyl acetate and the like. One or more of these monomers can be used by copolymerizing with (meth) acrylic acid ester as required.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited and can be arbitrarily set, but is usually preferably 20 μm or more, more preferably 30 μm or more, and particularly preferably 40 μm or more. However, the upper limit is usually preferably about 1000 μm.

  In the present invention, the pressure-sensitive adhesive layer can be formed, for example, by directly applying a solvent-based or emulsion-based pressure-sensitive adhesive to the film of the present invention and drying the film. A method of applying an adhesive layer to the film of the present invention and the like can be applied.

  Until the pressure-sensitive adhesive sheet is used, the surface of the pressure-sensitive adhesive layer may be protected with a release liner, and the pressure-sensitive adhesive sheet may be used by peeling the release liner during use. In addition, as a release liner, the thing similar to the above-mentioned cover separator can be used, for example.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not restrict | limited to the following example. In addition, the concrete test method implemented here is as follows.

<Measurement of weight average molecular weight>
GPC measurement conditions: The syrup was diluted with THF, filtered through a 0.45 μm membrane filter, and GPC measurement was performed. As an analyzer, HLC-8120GPC manufactured by TOSOH was used. The measurement conditions are as follows.
Column: TSKgel, superHZN-H / HZ4000 / HZ3000 / HZ2000
Column size: 6.0 mmI. D. × 150mm
Eluent: THF
Flow rate: 0.6ml / min
Detector: RI
Column temperature: 40 ° C
Injection amount: 20 μm
The molecular weight was produced in terms of polystyrene (PS).

Example 1
In a vessel equipped with a stirrer, a reflux condenser and a nitrogen introduction tube, 100 g of isobornyl acrylate, 80 g of methyl acrylate and 80 g of butyl acrylate as acrylic monomers, 40 g of N-vinylpyrrolidone as a nitrogen-containing monomer, photopolymerization initiator As a result, Irgacure 651 and Irgacure 184 (both manufactured by Ciba Specialty Chemicals) were added 0.2 g each, and nitrogen was blown in with stirring to remove dissolved oxygen. Ultraviolet irradiation was performed with a spot type ultraviolet irradiator (HOYA CANDEO OPTORONICS Co., Ltd.) to obtain a partial polymer (hereinafter abbreviated as syrup). The ratio of components having a weight average molecular weight of 1 million or more in the syrup was 7% by mass.
7 g of this syrup, 2 g of polytetramethylene ether glycol (trade name: PTMG650, manufactured by Mitsubishi Chemical Corporation, molecular weight of about 650) as a diol, 1 g of polyfunctional isocyanate (trade name: Coronate HX, manufactured by Mitsui Chemicals), urethanization reaction catalyst After adding 0.001 g of dibutyltin dilaurate and mixing uniformly, the thickness is applied to a polyethylene terephthalate base material (trade name: MRF38, Mitsubishi Plastics, Inc.) (hereinafter abbreviated as PET separator) that has been subjected to a silicone-based release treatment. The coating was applied to a thickness of 0.2 mm, and a light-peeling type PET separator (MRE38) was covered as a cover separator, followed by irradiation for 5 minutes with the same ultraviolet irradiator for polymerization. The cover separator was peeled off, and subjected to a urethanization reaction by heat treatment at 120 ° C. for 5 minutes and 150 ° C. for 5 minutes to obtain a film A.
The film A was analyzed by a transmission electron microscope (hereinafter abbreviated as TEM). As a result, a sea-island structure was formed by phase separation, the sea part was an acrylic polymer (A), and the island part was crosslinked urethane. It was found to be a union (B). The average size of the island portions was 600 nm. FIGS. 1A and 1B show a TEM image of film A at a magnification of 10,000 times and a TEM image at a magnification of 25,000 times, respectively.

(Example 2)
An experiment was performed under the same conditions as in Example 1 except that acryloylmorpholine (trade name: ACMO, manufactured by Kojin Co., Ltd.) was used as the nitrogen-containing monomer, and film B was obtained.
When film B was analyzed by TEM, it was found that a sea-island structure was formed by phase separation, the sea part was an acrylic polymer (A), and the island part was a crosslinked urethane polymer (B). did. The average size of the island portions was 320 nm.

(Example 3)
An experiment was performed under the same conditions as in Example 1 except that PTMG650 was changed to 1.8 g and 1,4-butanediol 0.2 g (manufactured by Wako Pure Chemical Industries, Ltd.), and a film C was obtained.
When film C was analyzed by TEM, it was found that a sea-island structure was formed by phase separation, the sea part was an acrylic polymer (A), and the island part was a crosslinked urethane polymer (B). did. The average size of the island portions was 280 nm. FIGS. 2A and 2B show a TEM image of film C with a magnification of 10,000 times and a TEM image with a magnification of 25,000 times, respectively.

(Comparative Example 1)
An experiment was performed under the same conditions as in Example 1 except that 40 g of acrylic acid was used instead of the nitrogen-containing monomer, and a film D was obtained. In addition, when the film D was analyzed by TEM, the sea-island structure was not confirmed but it was a compatible state.

(Comparative Example 2)
Polyethylene terephthalate base material (product) to which 0.05 g of 1,6 hexanediol diacrylate (HDDA, manufactured by Daicel-Cytec) is added as a crosslinking agent to 10 g of the syrup prepared in Example 1 and subjected to a silicone-based release treatment Name: MRF38 (Mitsubishi Resin Co., Ltd.) (hereinafter abbreviated as PET separator) is coated to a thickness of 0.2 mm, covered with a light release type PET separator (MRE38) as a cover separator, and 5 with an ultraviolet irradiator. Polymerization was performed by irradiation for 1 minute to obtain a film E.

<Evaluation of self-healing>
The obtained films A to E were cut into 5 cm in length and 2 cm in width, and after making five scratches with a crack length of about 4 cm and a crack depth of about 50 μm with a cutter, the film was made at 100 ° C. for 5 minutes or at 120 ° C. for 5 minutes. The degree of difficulty of seeing the scratches was scored by a five-step evaluation by visual inspection. The results are shown in Table 1.
〔Evaluation criteria〕
5 points (no visible scratches)
3 points (slightly visible scratches)
1 point (scratches still remain)
In addition, 4 points | pieces are evaluations between 5 points | pieces and 3 points | pieces, and 2 points | pieces are evaluations between 3 points | pieces and 1 point | pieces.

<Evaluation of film strength>
The obtained films A to E were cut to 5 cm in length and 1 cm in width, and tested according to JIS-C-2318-72 using “Autograph-1kNG” (manufactured by Shimadzu Corporation) as a tensile tester. The sample was subjected to a tensile test at a tensile speed of 200 mm / min, a distance between chucks of 20 mm, and room temperature (23 ° C.) to obtain a stress-strain curve, and tensile strength, elastic modulus, and elongation at break were measured. The results are shown in Table 1.

From the results in Table 1, the films A to C of the present invention obtained in Examples 1 to 3 are excellent in strength and flexibility, and are excellent in self-healing that self-repairs by cutting a wound such as a cut or a large scratch by heating. It was found to have sex.
On the other hand, since the film D of the comparative example 1 did not use the nitrogen-containing monomer, it resulted in inferior self-repairability.
The conventional film E of Comparative Example 2 was inferior in self-repairability.

  The film of the present invention is excellent in transparency, heat resistance, weather resistance, strength and flexibility, and has an excellent self-repairing property that self-repairs a cut wound or a large scratch by heating, for example, a touch panel. It is useful as a surface protective film (or protective coating film) for an optical member such as a car body or a building material such as an automobile.

Claims (9)

An acrylic polymer (A) containing at least a nitrogen-containing monomer (a1) as a monomer unit, and a crosslinked urethane polymer (B),
The acrylic polymer (A) and the crosslinked urethane polymer (B) form a sea-island structure composed of a sea part and an island part, and the island part is the crosslinked urethane polymer (B), The sea portion is the acrylic polymer (A).   The content of the nitrogen-containing monomer (a1) is in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the total monomer units of the acrylic polymer (A). Film.   The ratio of the acrylic polymer (A) and the crosslinked urethane polymer (B) is 60/40 to 95 in terms of mass ratio of acrylic polymer (A) / crosslinked urethane polymer (B). The ratio of components having a weight average molecular weight of 1,000,000 or more in the acrylic polymer (A) is in the range of 3 to 10% by mass. The film described.   The film according to any one of claims 1 to 3, wherein the film is self-repaired by heating. A method for producing the film according to any one of claims 1 to 4,
A first step of preparing a first mixture containing at least a partial polymer obtained by polymerizing a monomer component containing at least a nitrogen-containing monomer (a1), a polyol (b1) and a polyisocyanate (b2);
In the first mixture, the partial polymer is further polymerized to form an acrylic polymer (A), which contains at least an acrylic polymer (A), a polyol (b1), and a polyisocyanate (b2). A second step of preparing a mixture of the two,
A third step of obtaining a film by reacting at least the polyol (b1) and the polyisocyanate (b2) in the second mixture to form a crosslinked urethane polymer (B);
A method for producing a film, comprising:   6. The method for producing a film according to claim 5, wherein in the first step, a ratio of a component having a weight average molecular weight of 1,000,000 or more in the partial polymer is in a range of 3% to 10%.   The method for producing a film according to claim 5 or 6, wherein in the first step and the second step, polymerization is performed by irradiation with energy rays.   In the second step, after the first mixture is coated on a support, the partial polymer is further polymerized by irradiation with energy rays to form the acrylic polymer (A), and then the first The method for producing a film according to any one of claims 5 to 7, wherein a film formed on the support is obtained by performing three steps.   A pressure-sensitive adhesive sheet comprising the film according to claim 1 and a pressure-sensitive adhesive layer provided on at least one surface of the film.