JP2000303019A - Release treatment agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To aim at simultaneously improving adhesion to various substrates and follow-up properties. SOLUTION: This release treatment agent has a reaction product of an ethylene/vinyl alcohol copolymer or a polyvinyl alcohol having a Young' modulus of at least 2.0×104 kg/cm2 and a flexural modulus of at least 2.4×104 kg/cm2 with an isocyanate having an >=8C aliphatic group as the effective component. The ethylene content is preferably not greater than 55 mol%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a release agent,
In particular, the present invention relates to a release treatment agent suitably used for a pressure-sensitive adhesive tape or an adhesive sheet using a plastic film or the like as a substrate.

[0002]

2. Description of the Related Art Conventionally, as a release treatment agent used for a substrate of a pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet, there are a silicone-based release treatment agent and a non-silicone-based release treatment agent. As the silicone-based release agent, addition-type, condensation-type silicone, and the like are used.
It has excellent properties such as releasability, residual adhesiveness, and heat resistance, but it is expensive, and it is necessary to heat set the support at a high temperature. Not applicable.

On the other hand, as the non-silicone release agent, a long-chain alkyl pendant polymer or the like is used, and the non-silicone release agent has lower properties such as releasability than the silicone-based release agent. However, for example, a release treatment agent using a long-chain alkyl pendant type polymer, which is a reaction product of an ethylene-vinyl alcohol copolymer and an alkyl isocyanate, disclosed in Japanese Patent Publication No. 60-30355, is practically sufficient. High peelability. Such a release agent does not require the use of a special catalyst or heat treatment, and can be released simply by applying a solvent solution of the release agent to the support and then drying it. The peeling process can be easily performed even on a support having a low (for example, a thermoplastic).

[0004]

However, in recent years,
With the high quality of pressure-sensitive adhesive products such as pressure-sensitive adhesive tapes and adhesive sheets, not only is the release agent required to have low peel resistance at the time of peeling, but also the release agent has an adhesive layer In order to prevent the performance of the pressure-sensitive adhesive layer from deteriorating due to the transition to the above, it is required that the adhesion of the release agent to the substrate be high. Further, since a plastic base material may be deformed (e.g., expanded or contracted) by heat or stress, it is required to improve the followability of a film of a release treatment agent to the deformation of the base material. If the release agent cannot follow the deformation of the substrate, peeling is likely to occur at the interface between the substrate and the release agent layer, and the release agent that has undergone interfacial destruction from the substrate will migrate to the adhesive layer and adversely affect the adhesive performance This is because

[0005] In this respect, even if the release agent is a long-chain alkyl pendant type polymer which is a reaction product of the ethylene-vinyl alcohol copolymer and the alkyl isocyanate, it has good adhesion to a plastic substrate. The balance of followability is not always sufficiently good.

[0006] It is an object of the present invention to provide a release treatment agent capable of achieving both a high level of adhesion and conformability to a substrate of a pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that ethylene-vinyl alcohol copolymers or polyvinyl alcohols having specific physical properties can be obtained by reacting them with alkyl isocyanate compounds. When a chain alkyl pendant type polymer was used as a release treatment agent, it was found that both the adhesion to a substrate and the followability were excellent, and the present invention was completed.

According to the present invention, the Young's modulus is at least 2.0 ×
Ethylene-vinyl alcohol copolymer or polyvinyl alcohol having 10 ⁴ kg / cm ² and a flexural modulus of at least 2.4 × 10 ⁴ kg / cm ² , and an isocyanate having an aliphatic group having 8 or more carbon atoms And a release agent containing a reaction product of the above as an active ingredient.

In the present invention, the Young's modulus of the polymer as a raw material of the long-chain alkyl pendant polymer as an active ingredient of the release treatment agent is at least 2.0 × 10 ⁴ kg / cm.
^Since it is ² , the adhesion of the long-chain alkyl pendant polymer obtained by the reaction between the raw material polymer and the isocyanate compound to the substrate is improved. At the same time,
The raw polymer has a flexural modulus of at least 2.4 × 10 ⁴
Since it is kg / cm ² , the ability to follow the expansion and contraction of the base material of the long-chain alkyl pendant polymer can also be improved. Therefore, the adhesive product treated with the present release treating agent can maintain the original adhesive performance for a long period of time. As described above, according to the present invention, the adhesion and the followability of the long-chain alkyl pendant polymer having the raw material polymer as the main chain to the base material are closely related to the physical properties (Young's modulus and flexural modulus) of the raw material polymer. The present invention has been found to be related, and in the present invention, based on such knowledge, the adhesion and followability of the release treatment agent to the substrate are improved.

In the present invention, when the main chain of the polymer is constituted as an ethylene-vinyl alcohol copolymer,
The Young's modulus is at least 2.0 × 10 ⁴ kg / cm ² ,
And a flexural modulus of at least 2.4 × 10 ⁴ kg / cm
² and its ethylene content is 55 mol
It has been found that the content is preferably 1% or less. Thereby, the releasability can be further improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The Young's modulus of an ethylene-vinyl alcohol copolymer (hereinafter sometimes simply referred to as “PEVA”) or polyvinyl alcohol (hereinafter sometimes simply referred to as “PVA”) has at least 2 0.0 × 10
⁴ kg / cm ² , preferably at least 2.4 ×
It is 10 ⁴ kg / cm ² . Young's modulus is 2.0 × 10 ⁴
If it is less than kg / cm ^{2, the} adhesion of the release agent to the substrate is not sufficient.

Although the upper limit of the Young's modulus is not particularly limited, for example, at most 5.0 × 10 ⁴ kg / cm ² ,
Preferably it is at most 4.5 × 10 ⁴ kg / cm ² . In addition, as the Young's modulus is larger, especially in the case of thin film treatment, the adhesion of the release agent to the substrate can be increased, but if it is too large, the film strength of the polymer decreases, and the residual adhesion rate decreases. Not preferred.

On the other hand, the flexural modulus is at least 2.4 ×
10⁴kg / cm²And preferably at least 2.
8 × 10⁴kg / cm²It is. Flexural modulus 2.4 ×
10 ⁴kg / cm²If it is less, it will
The follow-up property to it is not enough.

The upper limit of the flexural modulus is not particularly limited, but is, for example, at most 6.0 × 10 ⁴ kg / c.
m ² , preferably at most 5.3 × 10 ⁴ kg / cm ²
It is. It should be noted that as the flexural modulus is larger, the ability of the release agent to follow the substrate can be increased. However, if the flexural modulus is too large, the mechanical strength of the polymer decreases, and the residual adhesive strength decreases.

In the present invention, the Young's modulus is AS
The measurement is based on TMD-638. The flexural modulus is based on a value measured in accordance with ASTM D-790. They are,
ASTM (American Society for Testing and Material
s American Society for Testing and Materials).

The ethylene-vinyl alcohol copolymer used in the present invention, among the copolymers of the following formula (1), further has a Young's modulus of at least 2.0 × 10 ⁴ k
g / cm ² and a flexural modulus of at least 2.4 × 1
0 ⁴ kg / cm ² a is ethylene - vinyl alcohol copolymer or polyvinyl alcohol.

Embedded image

In the above formula (1), n is 0 or an integer of 1 or more, and m is an integer of 1 or more. n + m is 10
An integer of 0 to 3,000, preferably 150 to 2,500
Is an integer. That is, in the compound represented by the formula (1), the average degree of polymerization is 100 to 3,000, preferably about 150 to 2,500.

The ratio of n / (n + m), that is, the ethylene component in the compound represented by the above formula (1) is 0 to 0.9, preferably 0.55 or less (0 to 0.
55). Therefore, the ethylene content is 0 to 90 mol% (mol%), preferably 55 mol% or less (0 to 55 mol%). When the content of ethylene is 55 mol% or less, the releasability is improved. Of course, when the ethylene content is 0, the compound represented by the formula (1) is polyvinyl alcohol (PVA), and the ethylene content is 1
In the case of the above integer, it is an ethylene-vinyl alcohol copolymer (PEVA).

The isocyanate having an aliphatic group having 8 or more carbon atoms is not particularly limited as an aliphatic group, and examples thereof include an alkyl group, an alkenyl group, and an alkynyl group, preferably an alkyl group. The aliphatic group may be branched, but is preferably linear.

The number of carbon atoms in such an aliphatic group must be at least 8, but the upper limit is not particularly limited, and is, for example, 30 or less, preferably 20 or less.

More specifically, examples of the isocyanate compound used in the present invention include octyl isocyanate, lauryl isocyanate (dodecyl isocyanate), and stearyl isocyanate (octadecyl isocyanate). The isocyanate compounds can be used alone or in combination of two or more.

The release treatment agent of the present invention is a reaction product prepared by reacting a compound having the above-mentioned properties with an isocyanate compound having the above-mentioned properties (hereinafter referred to simply as “polymer urethane”). Is an active ingredient, but more specifically, for example, it can be prepared by the following method. First, an isocyanate compound and PEVA and / or PVA having predetermined physical properties are mixed, heated (for example, to about 80 ° C.), and if necessary, a catalyst (such as dibutyltin dilaurate) is added and dissolved. Thereafter, while stirring, the temperature is raised (for example, about 90 ° C).
) And, if necessary, a solvent (a solvent in which PEVA and / or PVA is soluble, such as dimethyl sulfoxide).
Thereafter, the temperature is further increased while stirring (for example, to about 140 ° C.)
Then, it can be prepared by reacting PEVA and / or PVA with an isocyanate compound.

Here, the ratio of the isocyanate compound is
Although not particularly limited, it is 0.5 equivalent or more based on the hydroxyl group in PEVA and / or PVA (for example, 0.5 to 1.5).
Equivalent), preferably about 0.6 to 1.1 equivalent.

The completion or end point of the reaction can be confirmed, for example, by measuring the residual amount of the isocyanate compound in the reaction mixture by infrared spectroscopy.

The high molecular urethane compound of the present invention can be separated from the reaction mixture by a conventional separation method (for example, a separation method such as precipitation). For example, after cooling the reaction mixture to 80 ° C., the reaction mixture is put into an alcohol (for example, methanol, isopropyl alcohol, etc.) in an amount of 3 to 6 times the reaction mixture, and the precipitate or the precipitate is filtered. And further deposits or precipitates with alcohol (such as methanol or isopropyl alcohol)
By washing with, a high molecular urethane compound can be separated from the reaction mixture.

The urethane polymer can be used alone or in combination of two or more.

In the release treatment agent of the present invention, a high molecular urethane compound can be used as it is, but a high molecular urethane compound can be used by dissolving it in a solvent. As such a solvent, for example, an oil-soluble organic solvent such as toluene and xylene can be used. in this case,
The concentration of the high molecular urethane compound in the release treatment agent is not particularly limited, and can be selected according to the purpose of use and the type of the pressure-sensitive adhesive tape or pressure-sensitive adhesive of the pressure-sensitive adhesive sheet. Note that the organic solvent can be removed by drying or the like after being applied to the substrate.

Since the release agent of the present invention contains the above-mentioned urethane compound as an active ingredient, the release agent has excellent releasability, and has high adhesion and followability to a substrate. Therefore, the transfer of the release agent to the pressure-sensitive adhesive layer is suppressed or prevented by the temperature change or expansion and contraction of the base material, and the decrease in the adhesiveness of the pressure-sensitive adhesive product can be suppressed or prevented. In addition, storage stability is high.
Therefore, it is extremely useful as a release treatment agent for a pressure-sensitive adhesive tape or adhesive sheet.

When the release treatment agent of the present invention is used as a release treatment agent for a pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet, a conventional coating device (for example, a roll coater, a gravure coater, a Meyer bar coater, a lip coater, etc.) is used. The release agent can be applied to the back surface of the pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet (the surface in contact with the pressure-sensitive adhesive) or the predetermined surface of the protective sheet.

In the present invention, the base material of the pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet or the base material of the protective sheet is not particularly limited, and examples thereof include plastics (for example, polyethylene,
Polypropylene, polyester such as polyethylene terephthalate, cellophane such as cellulose acetate, etc.) films, papers (eg, high quality paper, kraft paper,
Various substrates such as crepe paper, glassine paper, etc., filled papers (for example, impregnated paper, plastic coated paper, etc.), and cloth can be used, but a plastic film is preferable. The surface to be coated such as a plastic film may be subjected to a surface treatment by a conventional surface treatment method such as a corona discharge treatment or a plasma treatment.

The pressure-sensitive adhesive in the pressure-sensitive pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet is not particularly limited, and for example, a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, or the like can be used.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. (Example 1) 57 parts by weight of stearyl isocyanate was placed in a reaction vessel equipped with a stirrer having a Fowler blade, a reflux condenser, and a dropping float, and capable of heating and cooling. The modulus is 2.7 × 10 ⁴ kg / cm ² and the flexural modulus is 3.
6 × 10 ⁴ kg / cm ² , and the ethylene content in the ethylene-vinyl alcohol copolymer (PEVA) is 30
Mol% and an average degree of polymerization of 1,500 (hereinafter, the ethylene-vinyl alcohol copolymer is referred to as “PEVA-27 / 3”).
6 "), and dispersed by stirring. The solution was warmed to 80 ° C. in about 30 minutes,
0.036 parts by weight of dibutyltin dilaurate was gradually added and stirred to dissolve. While stirring and raising the temperature of this solution, 10 parts by weight of dimethyl sulfoxide (hereinafter referred to as “DM
(Abbreviated as "SO") over about 30 minutes, and after completion of the addition, the reaction temperature was increased from the temperature at the end of the DMSO addition (about 90 ° C.) to 140 ° C. over 60 minutes with stirring. After the reaction temperature reached 140 ° C., the reaction was continued under further sufficient stirring.

While confirming the progress of the reaction,
After stirring for about 120 minutes, it was confirmed that the reaction was completed. The progress of the reaction can be examined by appropriately sampling the reaction solution and measuring the amount of stearyl isocyanate in the reaction solution by infrared spectroscopy.

After completion of the reaction, the reaction solution was cooled to 80 ° C.
This reaction mixture was poured into methanol five times the total amount of the reaction mixture to obtain a white precipitate. Since DMSO in the reaction solution is dissolved in methanol, DMSO can be removed from the precipitate by a filtration method. Therefore, a white precipitate was separated by filtration, and further, this white precipitate was washed with methanol, dried, and pulverized to obtain a high molecular urethane compound.

(Example 2) PEVA was used as a raw material polymer.
In place of -27/36, Young's modulus is 2.4 × 10 ⁴kg
/ Cm²And the flexural modulus is 3.4 × 10⁴kg / c
m²And the ethylene content in PEVA is 40 mol%
And an ethylene having an average degree of polymerization of 1,300.
Use vinyl alcohol copolymer and
Example 1 except that the operation was performed under the conditions shown in Table 1.
In the same manner as described above, a high molecular urethane compound was prepared.

Example 3 PEVA was used as a raw material polymer.
In place of -27/36, Young's modulus is 2.4 × 10 ⁴kg
/ Cm²And the flexural modulus is 2.8 × 10⁴kg / c
m²And the ethylene content in PEVA is 47 mol%
And an average degree of polymerization of 1,500
Use vinyl alcohol copolymer and
Example 1 except that the operation was performed under the conditions shown in Table 1.
In the same manner as described above, a high molecular urethane compound was prepared.

Example 4 PEVA was used as a raw material polymer.
The Young's modulus is 4.5 × 10 instead of -27/36 ⁴kg
/ Cm²And the flexural modulus is 5.3 × 10⁴kg / c
m²And an average degree of polymerization of 200
Table 1 shows the reaction treatment operation while using alcohol.
Except for having performed under the conditions shown, it carried out similarly to Example 1, and
A high molecular urethane compound was prepared. DMSO is used
Not.

Comparative Example 1 PEVA was used as a raw material polymer.
In place of -27/36, Young's modulus is 1.5 × 10 ⁴kg
/ Cm²And the flexural modulus is 2.4 × 10⁴kg / c
m²And the ethylene content in PEVA is 60 mol%
And an average degree of polymerization of 1,500
Use vinyl alcohol copolymer and
Example 1 except that the operation was performed under the conditions shown in Table 1.
In the same manner as described above, a high molecular urethane compound was prepared.

Comparative Example 2 PEVA was used as a raw material polymer.
In place of -27/36, Young's modulus is 1.0 × 10 ⁴kg
/ Cm²And the flexural modulus is 1.6 × 10⁴kg / c
m²And the ethylene content in PEVA is 68 mol%.
And an average degree of polymerization of 1,500
Use vinyl alcohol copolymer and
Example 1 except that the operation was performed under the conditions shown in Table 1.
In the same manner as described above, a high molecular urethane compound was prepared.

Comparative Example 3 PEVA was used as a raw material polymer.
The Young's modulus is 0.7 × 10 instead of -27/36. ⁴kg
/ Cm²And the flexural modulus is 1.2 × 10⁴kg / c
m²And the ethylene content in PEVA is 75 mol%.
And an average degree of polymerization of 1,500
Use vinyl alcohol copolymer and
Example 1 except that the operation was performed under the conditions shown in Table 1.
In the same manner as described above, a high molecular urethane compound was prepared.

[0041]

[Table 1]

In Table 1, "PEVA" indicates an ethylene-vinyl alcohol copolymer, "PVA" indicates polyvinyl alcohol, and "DMSO" indicates dimethyl sulfoxide. "RNCO / OH" is PE
The ratio (equivalent) of the isocyanate compound to the hydroxyl group in VA or PVA is shown.

(Peeling Strength Test) Each of the high molecular urethanes obtained in Examples 1 to 4 and Comparative Examples 1 to 3 was dissolved in toluene to prepare a toluene solution having a concentration of 1.0% by weight. This solution is applied to a biaxially stretched polypropylene film so as to adhere as 0.05 g / m ² as a dry solid, and dried to prepare release treatment agent-coated films.

(Peeling strength test at 23 ° C.) A 25 mm wide rubber-based pressure-sensitive adhesive tape (trade name: Carton No. 640, Nichiban Co., Ltd.) ) And an acrylic pressure-sensitive adhesive tape (trade name: polyester tape No. 31B, manufactured by Nitto Electric Industry Co., Ltd.) are pressed using a rubber roller having a weight of 2 kg to produce test pieces for measurement.

The test piece was subjected to a 180 ° peel test at 23 ° C. at a peel speed of 0.3 m / min using an autograph (Model S-100, manufactured by Shimadzu Corporation) to obtain a peel strength ( (Unit: g / 25 mm) is measured. The measurement results are shown in Table 2. In Table 2, when an acrylic pressure-sensitive adhesive tape was used, a rubber-based pressure-sensitive adhesive tape was used in the “23 ° C.” column of the “peel strength” column of “Acrylic pressure-sensitive adhesive”. Is "23" in the column of "peel strength" of "anti-rubber adhesive".
° C ".

(Peel strength test after leaving at 50 ° C.) A test piece to which the pressure-sensitive adhesive tape produced in the same manner as described above was pressed was left at 50 ° C. for 24 hours under a load of 20 g / cm ^2. After that, a constant temperature and humidity chamber (temperature: 23 ° C, humidity: 6
After leaving at 5% RH for 2 hours, the peel strength (unit: g / 25 mm) is measured in the same manner as above. In addition, the measurement results are shown in Table 2. In the case of using an acrylic pressure-sensitive adhesive tape, in the case of using a rubber-based pressure-sensitive adhesive tape in the column of "50 ° C." Is "50 in the column of" peel strength "of" rubber pressure sensitive adhesive ".
° C ".

(Peeling strength test after stretching) The high molecular urethane compounds obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were each dissolved in toluene to prepare a toluene solution having a concentration of 1.0% by weight. did. This solution is applied to a biaxially stretched polypropylene film so as to adhere as 0.05 g / m ² as a dry solid, and dried to prepare release treatment agent-coated films.

Next, the release treatment agent-coated film thus produced is stretched by 10% in its entire length using an autograph (S-100, manufactured by Shimadzu Corporation). A 25 mm-wide rubber-based adhesive tape (trade name: Carton No. 640, manufactured by Nichiban) and an acrylic-based adhesive tape (manufactured by Nitto Denko Corporation) are applied on the stretched agent-coated surface of the stretched release agent-coated film. Then, pressure is applied using a rubber roller having a weight of 2 kg to produce test pieces for measurement. The peel strength (unit: g / 25 mm) of this test piece is measured in the same manner as described above. In addition, the measurement results are shown in Table 2. In the case of using an acrylic pressure-sensitive adhesive tape, in the case of using a rubber-based pressure-sensitive adhesive tape in the column of "after stretching" in the column of "peeling strength" of "relative to acrylic pressure-sensitive adhesive" Are described in the column of "after stretching" in the column of "peel strength" of "rubber pressure-sensitive adhesive".

(Residual adhesive strength test) Peel strength test (23 ° C.
These adhesive tapes were subjected to a SUS3 test in order to measure the residual adhesive strength of the pressure-sensitive adhesive tapes peeled off in the peel strength test, the peel strength test after standing at 50 ° C., and the peel strength test after stretching.
No. 04 stainless steel plate using the rubber roller as described above, and pressurized in a constant temperature and humidity chamber (temperature: 23 ° C., humidity: 65% R).
H) and leave for 2 hours. After standing, a 180 ° peel test is performed at a peel speed of 0.3 m / min in the same manner as the peel strength test, and the peel strength (unit: g / 25 mm) is measured. g / 25mm)
The residual adhesive strength is expressed as a residual adhesive rate (%) and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2.
When an acrylic pressure-sensitive adhesive tape was used, “23 ° C.”, “5
0 ° C. ”and“ after stretching ”, when a rubber-based pressure-sensitive adhesive tape was used,“ 23 ° C. ”,“ 50 ° C. ”, and“ 50 ° C. ”in the“ residual adhesion rate ”column of“ vs. After stretching ". Evaluation criteria: An adhesive tape that was not attached to the release-treated surface was attached to a stainless steel plate of SUS304, and a peel test was performed in the same manner as the peel strength test, and the peel strength of the untreated adhesive tape was measured. The residual adhesive force according to
The evaluation is made by the ratio (residual adhesion ratio) to the peel strength of the untreated pressure-sensitive adhesive tape. Therefore, the residual adhesion rate (%) is 10
A value closer to 0 indicates that the migration of the release agent component to the pressure-sensitive adhesive layer is small.

[0050]

[Table 2]

From Table 2, it can be seen that the release agents according to the examples have a sufficient release effect when kept at room temperature and high temperature as compared with the comparative examples. Therefore, the release agent according to the example has extremely high adhesion to the substrate even at a high temperature, and can suppress or prevent the transfer of the release agent to the pressure-sensitive adhesive layer.

Further, the release agent according to the example maintains a sufficient release effect even when the coated substrate is stretched after the release agent is applied to the substrate, as compared with the comparative example. ing.
Therefore, the release agent according to the example has an extremely high follow-up property to the expansion and contraction of the base material, and the separation at the interface between the substrate and the release agent hardly occurs. Therefore, even if the base material expands and contracts, transfer of the release agent to the pressure-sensitive adhesive layer can be suppressed or prevented.

Furthermore, the release agent according to the example can be applied to a very excellent substrate even when peeled in a state where it is kept at room temperature or high temperature and after being stretched after coating. , The transfer to the pressure-sensitive adhesive layer is very small, and the adhesive has very good residual adhesiveness.

Therefore, when the release agent according to the embodiment is used, the adhesive product can maintain the original release performance for a long period of time.

[0055]

The release agent of the present invention uses the raw material polymer having the above-mentioned physical properties, so that the release agent is excellent in releasability, and at the same time, has a high level of adhesion to the substrate and conformability. I have.

Claims (2)

[Claims] 1. A material having a Young's modulus of at least 2.0 × 10 ⁴ k
g / cm ² and a flexural modulus of at least 2.4 × 1
0 4 Ethylene is ^kg / cm ² - vinyl alcohol copolymer or polyvinyl alcohol, release treatment agent comprising as an active ingredient the reaction product of an isocyanate having at least 8 aliphatic group with a carbon number. 2. The release agent according to claim 1, wherein the ethylene content is 55 mol% or less.