JP2003301024A - Mold releasing agent and mold releasing film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-chain acrylic type mold releasing agent which causes no working problems, such as those associated with application, has a high hardening speed and high releasing performance for adhered surfaces and well meets characteristics required as a mold releasing agent. <P>SOLUTION: The agent has a reaction product of (A) a (meth)acrylic polymer containing specific repeated units with (B) a polyisocyanate compound in which an isocyanate group is bonded directly to both end aromatic groups each bonded through a 6C or higher aliphatic group as active ingredients. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a release agent and a release film, and more specifically, to a release agent containing a long chain alkyl group-containing acrylic copolymer as a main component, which has a small peeling force and excellent solvent resistance. The present invention relates to a mold release agent and a release film using the release agent.

[0002]

BACKGROUND OF THE INVENTION Adhesive sheets are used in many fields because they can be adhered to an adherend only by lightly pressing them, but these are usually used on the back side of a substrate having an adhesive layer on one side. A release layer is provided on the top to facilitate rewinding during use. For double-sided pressure-sensitive adhesive sheets and the like, a release film having a release layer on a support is used to facilitate protection of the pressure-sensitive adhesive surface and rewinding during use.

The release layer in the pressure-sensitive adhesive sheet or release film subjected to the back surface release treatment as described above is mainly classified into silicone type, long-chain alkyl type and wax type, and each material is selected according to the use. Are used properly. Of these, long-chain alkyl release agents do not scatter the silicone component due to heating, have a relatively high degree of freedom in synthesis such as the introduction of polar groups, and can control the physical properties of the polymer, so that oil-based ink printing is possible. It has the advantage of imparting properties, and is widely used for binding tapes, gum tapes, tapes for electronic materials that do not like silicone components, and the like.

The above long-chain alkyl releasing agent contains an acrylic copolymer having a long-chain alkyl group as a main agent, and is usually prepared as a coating solution using an organic solvent in order to secure viscosity and homogeneity. However, there is a problem with solvent resistance. In recent years, due to changes in the material system of pressure-sensitive adhesives, there has been an increasing demand for release agents having excellent peeling force and solvent resistance.

[0005]

As a method of imparting solvent resistance, a method of crosslinking an active ingredient of a release agent to form a gel component, and introducing a monomer component which is not soluble in a solvent are introduced. Examples of the method include a method of reacting a polyfunctional compound with another functional group for crosslinking. For example, a reaction between an epoxy group and a carboxylic acid or an amine, a ring-opening polymerization of an epoxy group or an oxetane group, a hydroboration reaction between an olefin compound and a hydroborane compound, and a urethanization reaction between an isocyanate compound and a hydroxyl group or an amino group are known. ing.

However, polar groups (hydroxyl group, ester group, urethane group, etc.) formed as a result of the above reaction are disadvantageous to the releasability, and all of them have a slow cross-linking and curing rate, so that the film has a releasing agent. There is a problem that it is difficult to cure the release film in a short time when the release film is coated and cured.

The present invention has been made in view of the above circumstances, and its purpose is to have no problem of workability (coating workability), excellent solvent resistance, high curing speed, and moreover, to an adhesive surface. It is an object of the present invention to provide a long-chain acrylic release agent that is excellent in release performance and sufficiently satisfies the original required properties as a release agent, and a release film using the release agent.

[0008]

That is, the first aspect of the present invention
The gist of is a (meth) acrylic polymer (A) containing each repeating unit represented by the following formulas (1) and (2).
And a polyisocyanate compound (B) in which an isocyanate group is directly bonded to both end aromatic groups bonded with an aliphatic group having 6 or more carbon atoms as an active ingredient. Exist in.

[0009]

Embedded image (1)-[CH ₂ —C (R ¹ ) COOR ² ]-(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 12 to 30 carbon atoms.) 2) - ^{_{[CH 2 -C (R 3) COOR}} 4 ] - (wherein, R ³ is a hydrogen atom or a methyl group, R ⁴ represents a hydroxyl group, an amino group, a thiol group, a functional group selected from the group consisting of carboxyl group Represents an alkyl group containing).

A second aspect of the present invention resides in a release film characterized in that a release layer containing the above-mentioned release agent is formed on at least one surface of a base film.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
First, the release agent of the present invention will be described. The release agent of the present invention is bonded to a (meth) acrylic polymer (A) containing each repeating unit represented by the above formulas (1) and (2) with an aliphatic group having 6 or more carbon atoms. The reaction product with the polyisocyanate compound (B) in which the isocyanate groups are directly bonded to the aromatic groups at both ends is used as an active ingredient.

The repeating unit represented by the formula (1) is formed from a (meth) acrylate monomer having 12 to 30 carbon atoms. Examples of such monomers include dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, cetyl (meth) acrylate, heptadeca (meth) acrylate, stearyl (meth) acrylate, icosyl (meth). Examples thereof include acrylates, docosyl (meth) acrylates, and (meth) acrylates having branched alkyl groups of these side chain alkyl groups.

On the other hand, the repeating unit represented by the formula (2) is formed from a (meth) acrylate monomer having a side chain of an alkyl group having a hydroxyl group or an amino group. The amino group is preferably a primary amine or secondary amine.
Examples of such a monomer include the following compounds.

Examples of the monomer having a hydroxyl group include 2-
Hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 2-, or 3-, or 4-hydroxycyclohexyl (meth) acrylate , 2-hydroxypropyl (meth) acrylate, 3-chloro-2
-Hydroxypropyl (meth) acrylate, tetraethylene glycol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate,
Examples include diethylene glycol (meth) acrylate, polyethylene glycol mono (meth) acrylate, N-methylol (meth) acrylamide, and the like.

On the other hand, examples of the monomer having an amino group include 2-aminoethyl (meth) acrylate, 2- (methylamino) ethyl (meth) acrylate, 2- (ethylamino) ethyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 3- (methylamino) propyl (meth) acrylate, 3- (ethylamino) propyl (meth) acrylate, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl ( Examples thereof include (meth) acrylamide, N- (2-amino) ethyl (meth) acrylamide, and N- (6-amino) hexyl (meth) acrylamide.

The (meth) acrylic polymer (A) in the present invention can be obtained by copolymerizing each of the above-mentioned monomers. At this time, the polymerization initiator is usually used in thermal polymerization. Known publicly known peroxides and azo-based initiators can be used.

In the above copolymerization, each monomer may be present in the polymerization system at the same time during the polymerization, or one of the monomers may be polymerized first, and the other monomer may be added during or after the polymerization. Monomers may be added. A random copolymer or a block copolymer can be obtained by such a method. In addition, a monomer other than the above may be gradually added during the polymerization.

The polymerization method is not limited, and melt polymerization, suspension polymerization, solution polymerization, emulsion polymerization and the like can be appropriately adopted. Therefore, the polymerization solvent is not particularly limited, and a solvent suitable for each method can be selected. Further, the copolymerization may be carried out without a solvent.

The molecular weight of the (meth) acrylic polymer (A) in the present invention is not particularly limited, but the molecular weight measured by size exclusion chromatography is 5,000.
The range of up to 500,000 is preferred.

In the (meth) acrylic polymer (A) of the present invention, the repeating unit represented by the formula (2) serves as a crosslinking unit for solvent resistance. Therefore, when the number of repeating units is large, not only gelation but also increase of peeling force due to increase of functional groups is caused, and when it is small, solvent resistance becomes insufficient. In the present invention, from the viewpoint of maintaining a balance between solvent resistance and peeling force, the repeating unit represented by the formula (1) /
The molar ratio of the repeating unit represented by the formula (2) is usually 90.
/ 10 to 99.99 / 0.01, preferably 95/5 to
It is 99.99 / 0.01.

When it is necessary to recover the polymer, a known method is used. For example, residual monomer and /
Alternatively, evaporation of the solvent, reprecipitation in a suitable solvent, filtration or centrifugation of the precipitated polymer, washing of the polymer and drying can be appropriately carried out. As the reprecipitation solvent,
Examples thereof include alcohols having 1 to 6 carbon atoms such as methanol, ethanol, and isopropyl alcohol, water, acetone, methyl ethyl ketone, and the like, with preference given to water, methanol, acetone, or a mixture thereof. The obtained polymer can be analyzed by size exclusion chromatography, NMR spectrum and the like according to well-known techniques, and can be used in the reaction with an isocyanate compound described later.

The polyisocyanate compound (B) in which an isocyanate group is directly bonded to both end aromatic groups bonded with an aliphatic group having 6 or more carbon atoms is a polyisocyanate compound (B) represented by the formula (2). Reacts with a hydroxyl group or an amino group of an alkyl group) to form a urethane bond or a urea bond.

The above polyisocyanate compound (B)
Is, for example, (i) a polyisocyanate compound having a blocked or unblocked isocyanate group, such as tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, Obtained by reacting an excess amount of a polyisocyanate compound such as paraphenylene diisocyanate with a low-molecular or high-molecular compound containing active hydrogen having 6 or more carbon atoms such as trimethylolpropane, trimethylolbutane, hexanetriol, polyolefin polyol oligomer and polylactone. Aromatic-terminated isocyanate-containing compounds, (ii) polymers of these polyisocyanate compounds, (iii) these unblocked polymers The cyanate compound polyisocyanate compound blocked the like with an isocyanate blocking agent.

In the above method of reacting a polyisocyanate compound with an active hydrogen-containing low molecular weight or high molecular weight compound having 6 or more carbon atoms, the raw material polyisocyanate compound used does not have an isocyanate group directly involved in crosslinking. In this case, it may have a unit of an aliphatic chain polyisocyanate compound such as hexamethylene diisocyanate or trimethylhexamethylene diisocyanate in the molecule, or an aliphatic cyclic polyisocyanate compound such as hydrogenated diphenylmethane diisocyanate or isophorone diisocyanate.

In the present invention, from the viewpoint of solvent resistance,
Polyisocyanate compounds having 3 or more aromatic isocyanate groups are preferred. The above polyisocyanate compounds may be used alone or in combination of several kinds.

The release agent of the present invention contains a reaction product of the above-mentioned (meth) acrylic polymer (A) and polyisocyanate compound (B) as an active ingredient, and is used in a release film described later. It That is, it is used by coating it on at least one surface of the substrate film. In this case, the above reaction (curing reaction with a polyisocyanate compound as a crosslinking agent) is carried out after applying both components to the surface of the base film. Therefore, the reaction between the (meth) acrylic polymer (A) and the polyisocyanate compound (B) will be described in the description of the release film.

Next, the release film of the present invention will be described. The release film of the present invention is characterized in that a release layer containing the release agent is formed on at least one surface of a base film.

In the present invention, the release layer is formed as follows. That is, a release agent-forming solution containing the above-mentioned (meth) acrylic polymer (A) and polyisocyanate compound (B) is prepared, which is applied and then dried and cured.

The solvent used to prepare the release agent forming solution is
Although not particularly limited, it is preferably a low boiling point. Examples of such a solvent include toluene, methyl ethyl ketone, ethyl acetate and the like.

The total concentration of the (meth) acrylic polymer (A) and the polyisocyanate compound (B) in the release agent forming solution is usually 1 to 10% by weight. Concentration is 1% by weight
When the concentration is less than 10, the release layer having a sufficient thickness is not formed on the surface of the base film, and when the concentration exceeds 10% by weight, the release layer formed on the surface of the base film is too thick. Mold release performance may decrease. Further, the releasing force can be adjusted by adding an additive or the like to the release agent forming solution.

The ratio of the (meth) acrylic polymer (A) to the polyisocyanate compound (B) used is selected according to the desired peeling force, but the hydroxyl group or amino group in the (meth) acrylic polymer (A) is used. The ratio (molar ratio) of the isocyanate group in the polyisocyanate compound (B) to the group is usually 0.90 to 1.50, preferably 0.95.
Is about 1.20. If the proportion of the polyisocyanate compound (B) is less than the above proportion, the solvent resistance may not be sufficient, and if the proportion of the polyisocyanate compound (B) exceeds the above proportion, the unreacted isocyanate group is It may remain, and the releasability may decrease.

A catalyst can be added to the release agent forming solution in order to promote crosslinking (curing) by the polyisocyanate compound (B). Examples of such a catalyst include tin compounds such as dibutyltin octanoate and dibutyltin laurate, and tertiary amines such as triethylamine. The concentration of the catalyst is not particularly limited, but is usually 10 to 1000 ppm as the concentration in the release agent forming solution.

As the substrate film, various conventionally known films such as paper, plastic laminated paper,
Cloth, plastic laminate cloth, plastic film, metal foil, foam and the like can be used.

The release agent forming solution is applied to the surface of the substrate film by an appropriate coating means such as a bar coater, a roll coater, a kiss coater, a slot die coater, a squeeze coater or a gravure coater. (Meth) acrylic polymer (A) and polyisocyanate compound (B) to be applied
The total amount of usually 0.01 to 10 g / m ^2, preferably in the range from 0.5 to 5 g / m ^2.

The reaction temperature of the (meth) acrylic polymer (A) and the polyisocyanate compound (B) is usually 50 ° C.
To 200 ° C, preferably 60 ° C to 180 ° C, more preferably 80 ° C to 150 ° C. The reaction time is usually 2 seconds to 1 minute from the viewpoint of maintaining productivity and solvent resistance.

In the release film of the present invention, the release layer is formed on one surface of the substrate film, and the adhesive layer is formed on the other surface of the base film to give a release sheet having a back surface release treatment. It can also be used.

The release film of the present invention and the above-mentioned back-side release-treated pressure-sensitive adhesive sheets do not show stickiness in the release layer, have excellent release performance on the adhesive surface, and have excellent solvent resistance. Therefore, the original required characteristics of the release layer can be sufficiently exhibited.

[0038]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the following examples, the following polyisocyanate compounds were used and the following evaluation methods were adopted.

(Polyisocyanate compound) (1) Mitsubishi Chemical Co., Ltd. "Mytec GP105A" (aromatic diisocyanate / aliphatic triol adduct (trifunctional isocyanate), 76% by weight ethyl acetate solution) (2) Mitsubishi Chemical Co., Ltd. "Mytec NY718A" (aliphatic diisocyanate / triol adduct (trifunctional isocyanate), 76 wt% butyl acetate solution)

(Evaluation method) (1) Peeling force [mN / cm]: Release film 30 m wide
m, 150 mm in length, and a commercially available adhesive tape having a width of 25 mm (“Nitto Tape N” manufactured by Nitto Denko Corporation)
o. 502 ") is reciprocated once with a rubber roller having a weight of 2 kg and reciprocated. After that, the adhesive tape was fixed by a tensile tester, the release film was peeled off by 180 ° at a speed of 300 mm / min at 23 ° C, and the peeling force (average value of two samples:
mN / cm) is measured.

(2) Retention rate [%]: The release film is immersed in toluene for 10 minutes, then taken out and dried at room temperature, and the above peel test is conducted to measure the peel force. Then, it is calculated by the following formula.

[Formula 1] Retention rate [%] = Peeling force before immersion in toluene / Peeling force after immersion in toluene 100

Production Example 1 33.5 g (99 mmol) of stearyl methacrylate, 0.13 g (1 mmol) of hydroxyethyl methacrylate and 35 g of toluene were placed in a flask equipped with a condenser substituted with nitrogen, a nitrogen introduction tube, a stirrer and a thermometer. Nitrogen was bubbled for 15 minutes. Azobisisobutyronitrile 657 mg (4 mmol) was added to this, and 75
Polymerization was carried out at ℃ for 5 hours. The number average molecular weight of the obtained copolymer was 20800 and the molecular weight distribution was 3.10 as measured by size exclusion chromatography calibrated with polystyrene standards. After completion of polymerization, acetone 500
The precipitate was reprecipitated in ml to obtain 30 g of a copolymer.

Example 1 1 g of the polymer obtained in Production Example 1 and trifunctional isocyanate "G"
11 mg of "P105A" was dissolved in 49 g of toluene, and a polyethylene terephthalate film having a thickness of 38 μm (“DIAFOIL T1” manufactured by Mitsubishi Kagaku Polyester Film Co., Ltd.)
00-38 "). It was applied at 7. This was heated at 150 ° C. for 20 seconds or 1 hour with a hot air circulation dryer to form a cured coating film, whereby a release film was prepared. The evaluation results are shown in Table 1.

Example 2 In the same manner as in Example 1 except that 0.01 g of 1,4-diazabicyclo [2,2,2] octane was further added as a catalyst, the release film was prepared in the same manner as in Example 1. Created. The evaluation results are shown in Table 1.

Comparative Example 1 In Example 1, trifunctional isocyanate was added to "NY71".
A release film was prepared in the same manner as in Example 1 except that the amount of 8A ”was changed to 21 mg. The evaluation results are shown in Table 1.

Comparative Example 2 In Example 1, trifunctional isocyanate was added to "NY71
8A ”was changed to 21 mg, and a release film was prepared in the same manner as in Example 1, except that 0.01 g of 1,4-diazabicyclo [2,2,2] octane was added as a catalyst. The evaluation results are shown in Table 1.

[0047]

[Table 1]

[0048]

EFFECTS OF THE INVENTION According to the present invention described above, there is no problem of workability (coating workability), excellent solvent resistance, fast curing speed, and excellent release performance for an adhesive surface. A long-chain acrylic release agent that sufficiently satisfies the original required properties as a release agent and a release film using the release agent are provided, and the industrial value of the present invention is great.

Continued front page    (72) Inventor Motohiro Seki             1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation             Inside the company F term (reference) 4F100 AK25B AK25K AK41A AK51B                       AT00A BA02 GB90 JB01                       JL14 JL14B                 4J034 AA01 AA06 BA03 DA01 DA02                       DA05 DA07 DC50 DP18 HA01                       HA07 HC12 HC13 HC52 HC54                       HC64 HC67 HC71 RA05 RA08

Claims (4)

[Claims] 1. A (meth) acrylic polymer (A) containing each repeating unit represented by the following formulas (1) and (2) and both ends bound by an aliphatic group having 6 or more carbon atoms. A release agent comprising a reaction product of a polyisocyanate compound (B) in which an isocyanate group is directly bonded to an aromatic group as an active ingredient. Embedded image (1)-[CH ₂ —C (R ¹ ) COOR ² ]-(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 12 to 30 carbon atoms.) 2) - ^{_{[CH 2 -C (R 3) COOR}} 4 ] - (wherein, R ³ is a hydrogen atom or a methyl group, R ⁴ represents a hydroxyl group, an amino group, a thiol group, a functional group selected from the group consisting of carboxyl group Represents an alkyl group containing). 2. The release agent according to claim 1, wherein R ⁴ in the formula (2) is a hydroxyl group or an alkyl group having an amino group. 3. A release film comprising a release layer containing the release agent according to claim 1 or 2 formed on at least one surface of a base film. 4. The release film according to claim 3, wherein the base film is a polyester film.